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PREFACE

Interest in planting and managing black walnut trees

continues at a high' level. The premium prices paid for

walnut logs, the value of the nut crop, and the satisfaction

derived from tending trees all contribute to this interest

and to the resultant need for information on how to grow

walnut trees. A workshop on walnut culture held in 1966

focused on the then existing information and identified some

of the research needed to obtain additional knowledge. A

second symposium in 1973 continued this process, and in 1981

a third symposium was held to summarize current information

on walnut and to establish the direction of research for the

next several years. These proceedings are the product of the

1981 symposium.

The symposium resulted from the same cooperative effort

that proved so effective for its predecessors. Primary among

these cooperators were Purdue University, the Walnut Council,

North Central Forest Experiment Statlon, and the Northern Nut

Growers Association. Numerous other institutions, industry

representatives, and private individuals contributed significant amounts of tlme and effort. Thls cooperation produced

not only a sucessful symposium but, of equal importance,

these proceedings.

The proceedings bring together in one publication much

of the currently available information needed to successfully

grow black walnut; much of thls information is new or has

been refined since the previous symposium. The 1973 pro-

_eedings served as a guide for several thousand people. We

expect that these proceedings wlll likewise serve as the

basis for management recommendations during the next decade.
i

4

" , CONTENTS

t Pag___ee

i The walnut council 4. perspective

! Gary G. Naughton ........ 1

I Walnut in perspective: the challenge continues

R. Max Peterson ..................................... 4

•Ambrosia beetles in your black walnut plantatlon--how serious are they?

Barbara C. Weber ..................................... 7 

Variation in inherent decay resistance of black walnut

John C. Hart .... .......... 12

Epldemlology of butternut canker

N. A_ Tisserat and J. E. Kuntz .............................. 18

J

The distribution and impact of butternut canker in Wisconsin

A. J. Prey and J. E. Kuntz . . ............................ 23

Reactlonsof Juglans species to butternut canker and implications for disease resistance

L. P. Orchard, J° E° Kuntz, and K. J. Kessler, Jr ..................... 27

Dieback, decline, and stem canker of black walnut in Wisconsin

J. E° Kuntz and A° J. Prey ......................... ...... -32

Developments in disease control of walnut anthracnose

• Steven Cline ....................................... 35

Walnut root rot in seedbeds, beellng-in beds, and storage

N. A. Tisserat, J. E. Kuntz, R° P. Gurles, and R. F. Camp . .......... 38

Black walnut curcullo: a factor in walnut nut production

Larry M. Blalr ...................................... 43 

•

Physiology and silvlculture of black walnut for combined timber and nut production

J. W. Van Sambeek and George Rink ............................ 47

Nut productlon--a valuable asset in black walnut production

Harold E. Garrett and William B. Kurtz .......................... 53

The status of black walnut tree improvement programs in the north central region

George Rink and Henry E. Stelzer .......... 57

. Indiana Division of Forestry black walnut tree improvement program

Mark V. Coggesha11 and Stephen G. Pennington ....................... 61

New directions in genetic improvement: grafted black walnut plantations

Walter F. Belneke ....... 64

Some .guidelines for selectlng black walnut planting sites

Felix Ponder, Jr ..................................... 69

]

The significance of allelopathy in black walnut cultural systems

• W, J. Reltveld ........................... ........... 73

Pruning for quality

Richard C. Schlessinger .............. 87

•

Principles of managing black walnut in natural stands

.BurneU C. Fischer .......................... 92

!
Growth of black walnut in a fertilized plantation

J. M. Braun and W. R. Byrnes ............................... 

Interaction of nitrogen fertilization and chemical weed control on four-year volume

growth of a black walnut plantation

P o E. Pope, Ho Ao Holt, and Wo R. Chancy ......................... 

Effects of selected cover crops on the growth of black walnut

P. L. Roth and R. J. Mitchell .............................. 

- .Black walnut seed: from tree to seedling

Robert D. Williams ....... • ............................ 

J

A screening of vesicular-arbuscular (VA) mycorrhizal forming fungi on black walnut seedlings

M. W. Mellchar, Ho E. Garrett, and G. S. Cox ................. 

A silvlcultural-economic model for black walnut

Warren Ho Kincaid, William B. Kurtz, and H. E. Garrett .................. 

The changing status of prime agricultural land: future implications

Luther Bo Hughes, Jr ............................. 

A case study of black walnut management costs

James E. Jones ....................................... 

Black walnut management costs: results of the 1981 survey

Timothy D. Marty and William B. Kurtz .......................... 

A critical look at the expected return on investment from planting black walnut seedllngs

Dwight R. McCurdy ............................. 

Walnut resource: availability and utillzatlon

• Larry R. Frye .... •.................................. 

Buyers perspective on marketing walnut trees

Neal E. Jennings ..................................... 

Cost sharing incentives for black walnut management

Robert W. Koenig ..................................... 

°

-- - ,] .... III " U II n mnmmnl nln nn n n nn ,J .L il . .L .IL ......
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I
THE WALNUT COUNCIL IN PERSPECTIVE 1

Gary G. Naughton 2

This twelfth annual meeting of the Walnut And, the competition will always be

Council is truly an auspicious occasion. We friendly because we know that--even in the fa

have already survived almost 4 times as long of our past 12 years of organized effort--waln

as the average new business enterprise in trees are becoming increasingly scarce. The

America, our numbers are still growing, andwe strength of consumer demand for walnut produc

have a right to be truly proud of our accom- continues to assure us that our only true com

plishments, petition in this business is with time and

o nature. We are truly fortunate that we need

Those of us who have had the good fortune not hold back, selfishly, from helping each

to have been part of this Council since its other. Our combined effort to overcome commo

beginning at Indianapolis in 1970 have had the problems is the source of our strength.

opportunity to see, first hand, the finest

groves of walnut trees on the face of this This is the Third Walnut Symposium. Each

earth. Not only seeing walnut trees in all in its turn has served to focus on the curren

their glory, but getting to know them and the "State of the Art" in walnut culture and

people who own, plant, manage, harvest, and management. And, as you shall see, each has

use walnut trees are the things which make the become progressively more fruitful in bringin

walnut Council go. us toward our goal of improving the production

of walnut and its many products. The proThe Walnut Council is unique among orga- ceedings from the 19663 and 19734 symposia,

nizations. Founded on the principle of sharing along with those from this year are an invalu

knowledge and experiences for the benefit of able collection of the best information

society, our membership is open to anyone with available for persons interested in walnut.

an interest in walnut. We are neither solely

scientific nor technical nor educational nor We still have a serious task ahead of us

recreational nor financial in our interests. Many of the problems we experience in our

Yet, we are all of these things in good personal endeavors with walnut are still unmeasure. Landowners, scientists, educators, solved and pose a challenge to us for the

manufacturers, and speculators all form future.

important parts of our Council. And all contribute to the benefit of the group.

PROBLEMS

Our significant strength is that we

challenge each other. We have the audacity to We are still looking for the magic formul

• ask the hard questions, the charity to share to solve the two biggest questions that

our ideas with others, and the grace to accept foresters the world over must constantly adcriticism--all of which are part of every dress. They are: i) "How many trees should 

• meeting we have ever held. plant?", and 2) "When should we harvest?"

From the beginning, the members of this I can assure you, today, that the best

Council have expressed an attitude of friendly answers to these questions will never be the

competition. Remarks such as "It's too bad

you folks can't grow as good walnut in your

part of the country as we do in my area" are

accompanied with the unspoken belief that even 3"Black Walnut Culture", proceedings of 

poor walnut trees are good property, walnut workshop, Carbondale, Illinois, August

2-3, 1966. USDA Forest Service North Central

Forest Experiment Station. (This workshop

held before start of the Walnut Council.)

Ipaper presented at the Black Walnut 4"Black Walnut as a Crop", proceedings o

Symposium, West Lafayette, Indiana, August the black walnut symposium, Carbondale,

10,14, 1981. Illinois. August 14-15, 1973, USDA For. Ser

2Gary G. Naughton, Chairman Assistant North Central For. Exp. Stn., Gen. Tech. Rep

State Forester, Kansas. NC-4, p. 97-100.
same for all of us. We still find that it all The result is that more partially

depends on "the situation and the terrain." processed material is being exported than before and this provides more jobs at home. The

It is quite possible to start with 1,000 situation has evolved to the point now that

or more seedlings per acre and plan the final the current slump in walnut prices is more a

harvest for the age of 200 years, producing function of the strength of the U.S. dollar

as a result exceptionally high quality veneer against other currencies than it is a function

10g which would be in demand throughout the of consumer demand.

world. But we also know that there is good

profit in stands which start at 200 to 300

trees per acre and are at final harvest stage ACCOMPLISHMENTS

in 60 to 80 years.

At the risk of overlooking something of

It is my opinion that we' need both styles significance in terms of this Council's

of management systems to complement each other, accomplishments, I will address only two.

The lo_ger rotations fit nicely into forest Naturally, it is my conclusion that these two

_management systems on public lands, while accomplishments are the most significant.

the shorter rotations are a matter of economic

practicality and reality on private lands.' In One is the fact that, under the crusading

any."case, walnut management requires a pro- leadership of Don Gott, Council member and

found and unwavering sense of optimism for the former Executive Director of the Fine

future. Hardwoods--American Walnut Association, we

obtained consumer protection labelling

One of the first externalproblems ad- restrictions for walnut products on the retall

dressed by this Council was the need for a market.

realistic and consistent National policy on

the export of raw walnut logs into the These attractive tags and labels have

•International market. This has proved to be a since become a hallmark of quality and rella-

• two-edged sword--an enigma of gigantic pro- bility for the American consumer. It is my

portions. As in most situations of this sort, understanding that the FH-AWA office at

idealism gets totally entangled and confused Indianapolis dispenses over 1/2 million of

with reality. From the beginning there was these labels annually. (See Article in 1973

general recognition that a problem existed in Symposium Proceedings, page 23).

this area , but no agreement on how to solve it.

The net effect of this accomplishment is

Ideally, the valuable natural, resources to protect and stabilize the market of walnut

of a nation (walnut in this case) serve that products, and consequently the producers from

nation best when they are exported as compo- farm to mill to factory. To paraphrase a

nents of finished products rather than as raw well-known commerical advertisement--'"When you

materials. But market forces are fickle. For are number one you are prouder."

example, in International markets there are

frequently substantial Import duties levied The second and most significant accomon consumer goods--because all nations recog- plishment I want to recognize is the communinlze the differences in capital flow and cation forum that this Council has established.

employment opportunities represented by the Although imperfectly developed this is our

contrast between a log and a piece of greatest asset. Because of the unique

furniture, structure of the Walnut Council--a fact already

dlscussed--the development and transfer of

• Human nature also dictates that the knowledge and information is rapid and contlnl_downer offering timber for sale is inter- uous.

ested in getting the best cash price, sometimes

in spi_e of the nationality of the buyer. Landowners have the opportunity to meet

and question research and industry interests

I believe that this problem has been more face-to-face on a person-to-person basis.

Or less solved by default. The major walnut When the links of the chain from production,

log processing companles--many of whom have research, industry, technology, and finance

had active membership in this Council since know each other as indlviduals true communlthe beglnnlng--have developed their own cation exists.

international markets and have substantially

Increased world demand for walnut pro.ducts by But, I want to offer a word of caution

introducing them to new customers in foreign here. Members of the Executive Commlttee--past,

countries, present, and future--have been and will continue to receive mail and telephone inquiries

relating to walnut from people outside their

• 2
normal sphere of operation and influence. We

must not forget our obligation to refer such

requests to appropriate people closer to the

situation. These might be consultants, service

foresters, extension specialists, researchers,

or industry people. The proper function of

the Council in this respect is to put the

request into the best hands available not to

directly respond to requests. Except for

general inquiries which can be handled by

. sending the appropriate printed information,

it is folly for someone in Kansas to try to

• . offer advice to a walnut grower in Indiana.

THE FUTURE

J

I have spent most of this period talking

about the past and I don't apoldglze for that.

Perspective depends upon looking back to see

where you have been so that you can decide

where you ought to go in the future. So,

" having been there, where do we go next?

I belleve that, first of all, the Walnut

Council is a vlable organization with a long

future ahead of it. This assumption leads to

the following suggestions as goals:

i. We should plan now for another

" symposium, to be held sometime between 1988 and 1990 . . .

• .

2. We should make a strong effort to

trlple our membership by 1985 (approx-

. imately 2,000 members), and work hard

to reach 5,000 by 1990.

3. We should serlously consider establishing some type of endowment fund

within the Council for the purposes of

financing research and/or educatlonal

efforts on the broad spectrum of

interest relating to walnut.

4 We should begin, at the first opportunity,, to aid in the establishment

: of state walnut associations,

patterned after the Council, but

affiliated only to the extent they

. wish to formalize.

5. We should plan now to hire a part-time

Executive Director in about 1990 and

to have this position become full-time

by about 1995.

• There is our challenge. Nothlng remains

• constant very long. "We must forge ahead or

fade into obscurity.

.
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WALNUT IN PERSPECTIVE: THE CHALLENGE CONTINUES 1

R. Max Peterson 2

I congratulate You on your joint meeting, But, as you know, the situation is quite

and on the extensive program whlch you have the opposite for black walnut and other flue

underway. The wealth of information exchanged hardwoods. We have an overutillzed resource.

at this meeting is impressive, and something Demand has been greater than supply for several

you can all be proud of. years_ And that gap is projected to widen over

• the next 50 years.

This forum continues to serve as the

catalyst for excellence in cooperation among Yet, to meet that demand, we're seeing only

publi_ agencies, colleges and universities, a slight increase in walnut growing stock,

,Industry, and landowners. That type of nationwide . . . and a significant decrease in

cooperation existed before this Council was inventories for trees larger than 15 inches in

formed. But it's better because of it. diameter.

When he invited me here, Gary Naughton In some states, this decrease in walnut

made it a point to tell me that former Chief inventories is quite significant. In Iowa, for

Ed Cliff keynoted the first of these walnut example, walnut growing stock inventories have

conferences in 1966--before the Walnut Council shrunk by more than a third in twenty

was even formed . . . and that John McGulre--who years . . . and sawtlmber inventories have been

was Chief just before me--gave the keynote reduced by more than half.

speech at the second of these conferences.

In Missouri, where I grew up, black walnut

So I'm pleased to be at Purdue, and to was a well-known and respected tree that was

keynote this third walnut conference . . . and valued, not only for the wood it produced, but

the second Jolnt meeting of your two groups, also for the nut itself. The inventory of

walnut growing stock in Missouri has shrunk by

But before I left the office to come out 3 percent between 1959 and 1972 . .., sawtlmber

here, I was discouraged to look at some of the inventories have diminished by 9 percent.

walnut data assembled by our forest survey 

staff. • Now let's admit it . . . that's discouraging.

But all of that bad news doesn't reflect the

Despite two of these conferences in the work you've been doing.

last 15 years . . . which focused on what

needed to be done about the problem of de- Jack Spencer of our forest survey staff at

cl!ning walnut quality and quantity . . . the North Central Station tells me that there's a

problem doesn't seem to be getting any better, lot of walnut planting going on . . . but that

At least, not very fast. the trees aren't yet big enough to show up in

the inventory figures.

As a generality, we have a lot of hardwood timber. Anyone driving through the East And Judging by the program here, it's

• can attest to that. In some parts of the quite likely that those walnut trees will grow

Eastern United States it's difficult to find faster, be better protected, produce more nuts,

markets for a number of hardwoods. Supply be better utilized, and be worth a lot more than

Slgnlfic_tly exceeds demand. Growth is much the generation of walnut trees we've been

g=eater than removals. We have an underutillzed working with in the past.

resource in hardwoods in general.

I say that because we've learned a lot

about growing walnut over the past 20 years.

ipaper presented at the Black Walnut

Symposium, West Lafayette, Indiana, August We've learned a lot about defining suitable

10-14, 1981. walnut sites. Enough to establish a reliable

2R. Max Peterson, Chief of the Forest system for site evaluation.

Se_iue, United States Department of 

i Agriculture, to the Joint meeting of the We've come to realize the beneficial

Walnut Council and Northern Nut Growers effects of weed control on walnut growth.

_tl Association, Purdue University, Lafayette, 

_I Indiana, August ii, 1981.

i
We've learned a great deal about the ularly well-suited to multiple use manage

possibilities of interplanting walnut with So it fits well into what we are trying 

nitrogen-fixlng trees and shrubs, on the Eastern National Forests.

Through Bry Clark's early research, we've Many of these National Forests have 

learned that thinning to favor walnut in black walnut programs, particularly in t

natural stands holds good potential for accel- improvement and plantation establishment.

eratlng the growth of the remaining trees.

For example, we are cooperating with 

And through the work of Walt Beinecke, Tennessee Valley Authority, and with the 

Dave Funk, Calvin Bey, and others we've come of Indiana, Kentucky, and Tennessee, in 

along way in walnut tree improvement. We've nance and progeny testing. These tests 

defined preliminary seed collection zones and several hundred selections over much of 

established improved seed sources. Three range for Black Walnut. If successful, 

states have initiated walnut tree improvement of these experimental outplantlngs on th

programs. National Forests will be converted to fi

generation seed orchards.

Each of these advances--and many others I

haven't mentloned--can lead to greater walnut We have been disappointed with the r

production. There's ample opportunity for from introducing walnut into cutover sta

even further advances in most of these impor- with es6ablishlng black walnut on abandon

rant areas, too. fields. Therefore, we will no longer ma

• special efforts to introduce walnut as a

The record of research accomplishment and component in mixed stands until we have 

research cooperation in walnut culture and prescriptions for doing it.

utilization is one which we can all be proud

of. However, we have established nearly 

• acres of black walnut plantation on the

• But developing all of that knowledge will National Forests over the past I0 years. 

not, by itself, solve the black walnut shortage of the earlier plantations were put on p

problem . . . the problem of declining quality sites. Some of the others apparently di

and increasing cost. receive proper site preparation or follow

treatments.

That problem can be moderated in the short

run, but not solved, through improved utill- Anyway, the results of these plantati

zatlon. That aspect of your work will become can't all be considered successful, thou

even more important as walnut prices increase, we're generally pleased with the plantati

effort.

A longer-term solution will come, however,

only to the extent that we put that knowledge We will continue to establish black

to work on a wlde basis . . . that landowners walnut plantations on suitable sites. M

and forest managers recognize the opportunities these Jill be on the Daniel Boone, Wayne-

in walnut, and actively manage for it. Shawnee, Mark Twain, and Monongahela Nat

Forests.

That's how we are challenged in the next

two decades . . _ in motivating and informing And where it occurs in natural stands

landowners. It's a challenge which Ed Cliff will continue to manage and favor black 

lald out at the first walnut workshop in as a component of mixed stands.

1966 . . . and which John McGuire reiterated

and emphasized in 1973. We don't have a lot of sites on the

National Forests which are suitable for

That challenge continues today .... because intensive walnut management. However, w

we need to devote much more energy and skill to use those that are there. Because, Just 

gettlng walnut management started on a slgnlfl- you're interested in increasing black wa

cant scale. We need to motivate landowners to production, we're interested in having t

manage for walnut. And we need to give them National Forests do their share.

the informa= tion they need to do it

right . . . information such as that presented However, to change the focus of our

at this conference, attention, let me quote John McGulre fro

keynote to the 1973 walnut conference:

We want to do our share on the National

Forests, by managing appropriate sites for He said that "the success or failure 

hlgh-quallty hardwoods. Growing walnut in our program to increase production of wa

natural stands over long rotations is partlc- and other fine hardwoods will depend on 
o

degree of participation by nonindustry private : The combination of all of the factors I've

landowners who own 70 percent of the hardwood Just cited indicate an especially auspicious

sawtimber. Their land includes most of the time for walnut management on private forest

productive walnut sites and nearly all the lands.

growing stock. We need to stimulate greater

interest among the small private landowners in But we've got to point out those oppordeveloping maximum productivity of their forest tunltles.

lands."

We have to speak from the economic point

How well are we doing with these landowners? of view--to let the landowner know that walnut

management can pay if it's done right, and on

Not as well as we should be. the right sites.

Yet, it seems to me that there are several • And after spending these several days at

factors--such as the current combination of Purdue . . . talking with each other.., we'v

market, incentives, and national mood--whlch. got to go out and talk with the landowner. 

should give landowners unprecedented motivation 

to grow walnut on appropriate sites. That challenge will always be with us.

First, the nature of the tree is such that

it canbe managed in harmony With nearly any

sort of landowner objective short of wilderness.

Second, there appears to be an emerging

interest in trees which produce nuts which

people can eat. 

Third, the outlook for walnut shows future

demand exceeding supply, and continued high

; Prices..

Fourth, it seems to me that the increased

use of wood for energy has a lot of landowners

coming to realize the value of their

woodiots . . . first for firewood, then for 

other products as well. 

But there's a danger there, too. The same

axe that's used to thin a woodlot . . . can be

used to wreck it as well. We must educate

landowners to recognize high-value hardwoods 

and leave them to grow to maturity.

Fifth, as the Forest Service and cooperating universities get further along with their

Eastern Hardwood Initiative, it may well open

up some additional opportunities to manage for

fine hardwoods . . . walnut included. This

Initiative is a broad-scale effort to find

some better uses and better markets for all

eastern hardwoods, particularly where they can

take over some of the uses which are placing

such demand on softwoods. It will probably have

_ some good effects upon the supply of fine

[ hardwoods as well.

I

And sixth, let me briefly note--since you

have a.broader discussion scheduled for your

program tomorrow--that in recent years, Congress

_ has legislated a comprehensive package of tax

i incentives and other forms of encouragement to

: help landowners quickly recover many of their

costs .

6 • 
°

We'_e learned a great deal about the ularly well-suited to multiple use manage

possibilities of interplanting walnut with So it fits well into what we are trying 

nitrogen-fixing trees and shrubs, on the Eastern National Forests.

Through Bry Clark's early research, we've Many of these National Forests have 

learned that thinning to favor walnut in black walnut programs, particularly in t

natural stands holds good potential for accel- improvement and plantation establishment.

crating the growth of the remaining trees.

For example, we are cooperating with 

And through the work of Walt Beinecke, Tennessee Valley Authority, and with the 

DaveFunk, Calvin Bey, and others we've come of Indiana, Kentucky, and Tennessee, in 

along way in walnut tree improvement. We've nance and progeny testing. These tests 

defined preliminary seed collection zones and several hundred selections over much of 

established improved seed sources. Three range for Black Walnut. If successful, 

States have initiated walnut tree improvement of these experimental outplantings on th

programs. National Forests will be converted to fi

generation seed orchards.

Each of these advances--and many others I

haven't mentloned--can lead to greater walnut We have been disappointed with the r

production. There's ample opportunity for from introducing walnut into cutover sta

even further advances in most of these Impor- with establishing black walnut on abandon

rant areas, too. fields. Therefore, we will no longer ma

special efforts to introduce walnut as a

The record of research accomplishment and component in mixed stands until we have 

research cooperation in walnut culture and prescriptions for doing it.

utilization is one which we can all be proud

of. However, we have established nearly 

• acres of black walnut plantation on the

But developing all of that knowledge will National Forests over the past i0 years. 

not, by itself, solve the black walnut shortage of the earlier plantations were put on p

problem . . . the problem of declining quality sites. Some of_the others apparently di

and increasing cost. receive proper site preparation or follow

treatments.

That problem can be moderated in the short

run, but not solved, through improved utili- Anyway, the results of these plantati

• zation. That aspect of your work will become can't all be considered successful, thoug

even more important as walnut prices increase, we're generally pleased with the plantati

effort.

A longer-term solution _-ili come, however,

only to the extent that we put that knowledge We will continue to establish black

to work on a wide basis . . . that landowners walnut plantations on suitable sites. M

and forest managers recognize the opportunities these will be on the Daniel Boone, Wayne-

in walnut, and actively manage for it. Shawnee, Mark Twain, and Monongahela Nati

Forests.

That's how we are challenged in the next

two decades . . _ in motivating and informing And where it occurs in natural stands

landowners. It's a challenge which Ed Cliff will continue to manage and favor black w

laid out at the first walnut workshop in as a component of mixed stands.

1966 . . . and which John McGuire reiterated

and emphasized in 1973. We don't have a lot of sites on the

National Forests which are suitable for

That challenge continues today . . . because intensive walnut management. However, w

we need to devote much more energy and skill to use those that are there. Because, Just 

getting walnut management started on a signlfi- you're interested in increasing black wal

cant scale. We need to motivate landowners to production, we're interested in having t

manage for walnut. And we need to give them National Forests do their share.

the information = they need to do it

right . . . information such as that presented However, to change the focus of our

at this conference, attention, let me quote John McGuire from 

keynote to the 1973 walnut conference:

We want to do our share on the National

Forests, by managing appropriate sites for He said that "the success or failure 

high-quality hardwoods. Growing walnut in our program to increase production of wal

natural stands over long rotations is pattie- and other fine hardwoods will depend on 

|
°

degree of participation by nonindustry private The combination of all of the factors l've

landowners who own 70 percent of the hardwood Just cited indicate an especially auspicious

sawtimber. Their land includes most of the time for walnut management on private forest

productive walnut sites and nearly all the lands.

growing stock. We need to stimulate greater

interest among the small private landowners in But we've got to point out those oppordeveloping maximum productivity of their forest tunitles.

lands."

We have to speak from the economic point

How well are we doing with these landowners? of _rlew--to let the landowner know that walnut 

management can pay if it's done right, and on

NOt as well as we should be. the right sites.

Yet, it seems to me that there are several And after spending these several days at 

factors--such as the current combination of Purdue . . . talking with each other.., we've

market, incentives, and national mood--which got to go out and talk with the landowner. 

should give landowners unprecedented motivation 

to _g'rowwalnut on appropriate sites. That challenge will always be with us. J

First, the nature of the tree is such that

it can be managed in harmony With nearly any

sort of landowner objective short of wilderness.

Second, there appears to be an emerging

interest in trees which produce nuts which

people can eat. 

Third, the outlook for walnut shows future

demand exceeding supply, and continued high

• prices.

Fourt h , it seems to me that the increased

use of wood for energy has a lot of landowners

coming to realize the value of their

woodlots . . . first for firewood, then for 

other products as well. 

• But there's a danger there, too. The same

axe that's used to thin a woodlot . . . can be

used to wreck it as well. We must educate

landowners to recognize hlgh-value hardwoods

and leave them to grow to maturity.

Fifth, as the Forest Service and cooperating universities get further along with their

Eastern Hardwood Initiative, it may well open

up some additional opportunities to manage for

fine hardwoods . . . walnut included. This

Initiative is a broad-scale effort to find

some better uses and better markets for all

eastern hardwoods, particularly where they can

, take over some of the uses which are placing

such demand on softwoods. It will probably have

I some good effects upon the supply of fine

hardwoods as well.

i

And sixth, let me briefly note--since you

. have a broader discussion scheduled for your 

program tomorrow--that in recent years, Congress

: has legislated a comprehensive package of tax 

: incentives and other forms of encouragement to

', help landowners quickly recover many of their 

costs.

' 

i

! 6

i . 
AMBROSIA BEETLES IN YOUR BLACK WALNUT PLANTATION--

.

HOW SERIOUS ARE THEY?

Barbara C. Weber

Abstract.--The llfe history of Xylosandrus _ermanus and

its effects on black walnut trees were studied from 1976 to

1980 in two plantations, one in North Carolina and one in

_ _ Illinois. X. germanus has two generations per year with the

heaviest attack period occurring in May and June. Signs and

symptoms of attack include pinholes, basal sprouts, wilted

• leaves, and top dieback. Although tree survival is little

affected by X. germanus attacks on black walnut, growth

losses are potentially serious depending on the age of the

trees when attacked and the management goals of the plantation. Some management and silvicultural control recommendations are included.

At the last Black Walnut Symposium in 1973, SEASONAL LIFE HISTORY

one of the insect problems discussed was an

imported ambrosia beetle, Xylosandrus germanus Adult female X. germanus are black 

(Blandford), that was associated with an unex- approximately 0.I i--nch(2.5 millimeters) 

plalned dleback of young black walnut trees (fig. i). Males are brown and about 0.

(Juglans nigra Linnaeus) in Illinois and Indiana. (1.5 millimeters) long but are rarely se

At that time, little was known about the beetle, because they do not fly and usually do 

but since then we have learned much about its leave the gallery in which they live. 

llfe history and about the damage it does to immatures are white, legless, and wormli

• black walnut trees. The purpose of this paper They live in galleries made by the paren

is to briefly summarize what we have learned female in trees or other woody plants (

about the biology of X. germanus, to describe

the effects of attack on black walnut trees, and

to recommend some ways to reduce the damage by 0.04 inc

this insect. I 

Much of the information presented in this

paper comes from the study of X. _ermanus from

- 1976 to 1980 in two black walnut plantations.

One plantation is located in McDowell County,

North Carolina; the approximately 12 acres (4.9

hectares) were planted in 1973 and were attacked

byX. germanus in spring 1976 and probably also

_n 1974and 1975. Study of X. germanus was

' concentrated in a 5-acre (2.0 hectares) area

located in the center of the plantation. The

second plantation is located in Alexander

• County, Illinois; the approximately 7 acres

. (2,8 hectares) were also planted in 1973 but

were not attacked by X. germanus untll spring

• 1978.

IResearchEntomologlst, North Central

Forest Experiment Station, Forestry Sciences Figure l.--Side view drawing of adult fe

Laboratory, Carbondale, Illinois. X. germanus. (Drawing by S. W. Wilso
MAR APR MAY JU" JUL *UG SEP OCT

ADULTS _ _il

;-.r_ SaGS llll

_ .,.)_ LARVAE I1_

":'_*_'1;°"",.... ADULTS II

' _ .,:, :_. saos I

•' _III

_" "_**" " _' IS:;]';':" """ LARVAE

"_*_:_ " ";':" PUPAE I I /

t

-,. Figure 3.--Combined life history diagram of

_,__j,, -.. . ,

, ._;_ . and Illinois.

g:";":"'(:"'] DISTRIBUTION AND HOSTS

The ambrosia beetle X. _ermanus was first

"_:" '_;_ reported in the United States in 1932 on Long

_' ....._;-_,_;_;,_ Island, New York (Felt 1932). The beetle now

occurs from New York to Missouri and from

• Figure 2.--Cross section of black walnut show- Louisiana to South Carolina. It attacks several

ing X. germanus gallery, kinds of woody shrubs and trees _- In its native

country of Japan, X. germanus attacks about 160

different species of plants (Nobuchi 1981).

Adult females leave their overwlntering In the United States, Deyrup (1981) reported

sites in galleries at the bases of trees in that in Indiana alone it attacks 20 different

March and April to search for new hosts. They species of plants, including black walnut. 

fly primarily in the late afternoon and early

evening. The beetles are slow, weak flyers Miller (1973) and Kessler (1974) first

and are, therefore, easily carried by the wind. reported attacks by X. germanus on black walnut

In North Carolina, beetles in flight are present in Illinois. Since then, many more damaged

from late March until late August. In Illinois, plantations have been found (table I).

beetles in flight are present from early April

until early September. The average flying

height is 4.9 feet (1.5 meters). SYMPTOMS OF ATTACK

Once the beetles have located their new Signs and symptoms of X. germanus attack

hosts, they bore into the tree and excavate on black walnut trees include pinholes, basal

the galleries in Which they will lay their sprouts, wilting leaves, and dieback. Pinholes

eggs and produce new adults. X. germanus are approximately 1/32 inch (I millimeter) in

apparently has two generations per year. In diameter and are usually found in the lower

North Carolina, egg-laylng occurs from early trunk of attacked trees. Pinholes may also be

, May to pro_ably late June and from early June found in branches that are within about 6.5

to early September. Adults of the first feet (2 meters) from the ground. Basal sprouts

(summer) generation are present from mld-May originate from the tree trunk at or below the

to mld-Julyand those of the second (over- groundline or they may occur above the ground-

. winter£ng) generation from early July to the llne on the lower trunk. Wilting leaves and

end of the season. In Illinois, egg-laying dieback may occur over the entire aboveground

occurs from mid-May to early June and from . portion of the tree or on only one branch (fig.

late June to late July. Adults of the summer 4). Wilted and dead tops are the most easily

. generation are present from early to late June detected symptoms of attack and can be found

and those of the overwintering generation from most frequently during May and June, the period 

,_ mld-July to the end of the season (fig. 3). of heaviest attack by X. germanus. Occasionally,

The number of offspring per female ranges from cankers are also associated with beetle attacks.

2 to 53.

8
Table l.--Location, age, and height of plantation Sometimes the only symptom of attack 

black walnut trees attacked by X. 8ermanus the pinholes, but they are small and diffic

to find. In the Illinois plantation, I fo

that the percentage of trees attacked by mX

Age when Avg. ht. germanus could be estimated from the percen

Location attacked I (ft.) I of trees that had wilted leaves or dead to

Work is continuing to determine if this me

ILLINOIS of estimating the number of trees attacked 

X. germanus can be applied to all walnut p

Alexander County 5 6.0 t--ations.

Jackson County 4 5.3

INDIANA EFFECTS OF ATTACK

Daviess County - - The effect of attack by X. germanus o

Du Bois County 8 4.9 survival is less serious than first appeara

Fountain County i seedlings show, although initial tree losses may app

Green County - - high. Although the tops of attacked trees 

Hamilton County I _ seedlings die, the roots are usually still alive and 

Washington County 5 - out sprouts that can replace the original 

Approximately 350 of the 1,400 trees in th

NORTH CAROLINA North Carolina plantation were attacked by 

June 1976 and approximately 30 trees died.

McDowell County 3 5.6 About 330 of the 2,220 trees in the Illino

plantation were attacked in spring 1978. 

OHIO 75 percent of the attacked trees suffered 

dieback. All but four of the trees with t

• Scioto County 1-7 - dieback eventually sent up basal sprouts f

the still-living roots. If sprouts are pr

TENNESSEE to one per root system, the original attack

trees can be replaced by fast-growing spro

Davidson County 2 3.9 and thus reduce the effects of X. germanus 

tree losses in a plantation. However, the 

required to cut and remove beetle-lnfested

IDashed line means that the age and/or trees and to remove excess sprouts can be 

height of the trees at the time of attack were nificant and costly.

not known.

The effect of beetle attack on tree g

is potentially more serious than on tree s

vival. In the Illinois plantation, the av

_'_...... °" height of trees attacked by X. _ermanus in

..... spring 1978 was 5.7 feet (1.7 meters) comp

_ 0__ _ _ toThe 6.1average feet diameter (1.9 meters) at breast for _rees heightnot (dbh

att

i_a_ " ;j'_ trees attacked was 0.5 inch (1.3 centimeter

Jr_#_ ....... _ ,_ _ j_ i_i_ compared to 0.6 inch (1.4 centimeters) for 

,,_ _,i_' 0_'_ not attacked. After three growing seasons

•' _° _ _ _' average height of those trees attacked in 

1978 was 8.5 feet (2.6 meters) compared to 

feet (3.0 meters) for trees not attacked.

. Average dbh of attacked trees was 1.0 inch

(2.6 centimeters) compared to 1.3 inches 

centimeters) for trees not attacked. Thes

comparisons show that X. germanus apparentl

selected smaller trees and suggest that sm

trees may be more susceptible to attack th

larger ones. Younger trees may also be pr

ferred because all of the plantations in w

we found X. germanus were less than 8 year

when attacked. Black walnut trees older 

Figure 4.--Wilting leaves and top dieback of i0 years or more than about 2.5 inches (6

black walnut tree attacked by X. germanus, centimeters) in dbh probably will not be
attacked bY _" germanus. It is not known more flexible management goals, most trees

whether the smaller trees in the Illinois plan- attacked by X. germanus that are not comparable

tatlon Were attacked because they were less in size to trees not attacked will probably be

healthy than. the larger ones or whether they removed by harvest time.

were simply slow growers and were preferred by

X. germanus because of their smaller size. Another factor in assessing the seriousness of X. germanus attack is the genetic backThe comparisons of sizes of attacked and ground of the trees. The Illlnois plantatlon

not attacked trees also show that the attacked was designed to compare growth characteristics

trees, or their replacement sprouts, were not of trees from different sources in six States--

able to catch up in height and diameter growth, Arkansas, Illinois, Kansas, Kentucky, Missouri,

three growing seasons after attack, to those and Tennessee. Kansas trees were attacked

trees not attacked. The attacked trees may be least frequently (2 percent) and Kentucky trees

compared to the coppiced trees studied by were attacked significantly more often than

Schleslnger (1981). He found that 5 years trees from any of the other sources (13 percent)

after treatment (that is, removing the entire (table 2). These results suggest that genetic

abo_eground portion of copplced trees and variation in susceptibility to attackmay be

_allowlng one sprout to replace the original important. Further study in this area is

tree), coppiced trees were about 20 percent needed.

shorter in height and about 26 percent smaller

in dbhthan noncoppiced trees. Schleslnger

(1981) also found that the older the tree at Table 2.--Trees from each State attacked by X.

_he time of copplclng, the less llkely it germanus in spring 1978 in the Alexander

would be able to catch up in size to non- County, Illinois, black walnut plantation

copplced trees. Trees copplced when they were

2 years old were only about half a year "younger" in size at age ii than same-age noncopplced Total %

trees, but trees copplced when they were 5 State no. trees attacked

• years old were 3 years "younger" in size at

age !i than same age noncopplced trees. That Arkansas 233 9

is, trees coppiced at age 5 would have to grow Illinois 261 7

for 3 moreyears after the harvesting of non- Kansas 59 2

coppiced trees tO equal the size of the non- Kentucky 354 13

copplced trees. These findings suggest that Missouri 159 5

trees attacked by X. germanus when they are Tennessee 928 7

younger (for example, 2 years old) will be

• closer in size at harvest time to'trees not

@ttacked, and, thus, more likely to be selected

as harvest trees, than trees attacked by X. An aspect of concern, however, is the

germanus when they are older (for example, 5 planting of large numbers of trees from a few

years or more), seed sources (a seed source refers to the

parent tree) or grafted seedlings taken from

The seriousness of growth losses due to only one or two trees if one or more of these

X. germanus attack depends on the total number seed sources or clones are susceptible to

of trees attacked and the management goals for beetle attack. If the grafted portion is

the plantation. If a large percentage of the attacked and sprouts are produced by the root

trees has been attacked, the average tree size stock, the selected, superior growth charactermay be significantly reduced, as indicated in istlcs or nut potentlal of the grafted portion

the Illinois plantation, and result in a longer are lost and the tree's value is reduced to

time to final harvest of commerclal-sized trees, that of a normal, nursery-run tree.

If management goals require that all planl tatlon trees become final crop trees, every CONTROL RECOMMENDATIONS

tree is important. No tree loss and little

I growth loss can be tolerated. Such situations Good management and silvicultural control

, may develo p when few trees are planted origi- practices may provide the best options for

nally, on the other hand, if more trees are minimizing damage by X. germanus. Direct chem-

' planted initially than are needed for flna_ ical control of the insects on walnut trees is

crop trees, individual tree selections can be not practical because the beetles spend most

mad e periodically to keep the faster-growlng, of their llfe cycle within trees where chemical

'i straighter trees and eliminate the slower- sprays cannot penetrate. Treatment with systemic

l growing, less desirable ones. Under these insecticides may be effective during the initial 

i0 •

!

l
°

s_ages of attack, but no research has been done Schleslnger, R. C. 1982. Pruning for 

to test their effectiveness. Therefore, I Proceedings Black Walnut Symposium, 

recommend the following practices to reduce the University, West Lafayette, Indiana

effects of X. germanus on black walnut planta- 9-13, 1981. USDA For. Serv. Gen. T

tlons. NC- . North Cent. For. Exp. Stn.

Paul, MN.

I. Select planting sites that have deep,

well-drained soils; if possible, have your

local forester examine the site.

2. Plant trees at close spacing (e.g.,

i0 feet x I0 feet [3m x 3m]) to allow later

thinning and selecting for the best trees.

3. Plant trees from several locations or

seed sources to reduce the chances of severe

losses if one or two seed sources are highly

susceptible to --X. germanus attack.

4. Manage the trees, especially during

_ the first I0 years, wlth techniques known to

promote rapid growth. Examples of such techniques would be weed control and interplantlng

wlth nitrogen-flxlng plant species such as

autumn olive.

5. Treat fresh hardwood stumps within a

1/4 mlle (about 500 meters) radius of the

plantation with diesel fuel or other stump

treatment because X. germanus often live in

stumps in cutover forested areas.

6. Remove affected trees from the plantation as soon as possible after attack by X.

germanus, evidenced by wilting or dead tops.

• Destroy them to prevent population buildup

within the plantation.

LITERATURE CITED

Deyrup, M. 1981. Annotated list of Indiana

Scolytidae (Coleoptera). Great Lakes

Entomol. 14:1-9.

Felt, E. P. 1932. A new pest in greenhouse

grown grape'stems. J. Econ. Entomol. 25:

418.

Kessler, K. J., Jr. 1974. An apparent

symbiosis between Fusarium fungi and

ambrosia beetles causes canker on black

walnut stems. Plant Dls. Rep. 58:1044-1047.

Miller, W. E. 1973. Insects as related to

wood and nut production, p. 91-96. In

Black Walnut as a Crop, Black Walnut Symposlum, Carbondale, Illinois, August 14-15,

1973. USDA For. Serv. Gen. Tech. Rep. NC-4,

114 p., illus. North Cent. For. Exp. Stn.,

St. Paul, MN.

Nobuchl, A. 1981. Studies on Scolytidae XXIII.

The ambrosia beetles of the genus Xy!osandrus

Reltter from Japan (Coleoptera). Bull. of

the Forest. and For. Prod. Res. Inst 314,

p, 27-37.

• 
VARIATION IN INHERENT DECAY RESISTANCE OF BLACK WALNUT 1

.

John H. Hart2

Abstract.--Sapwood and heartwood from fast-growing black

walnut decayed at the same rate as sapwood and heartwood

collected from slow-growing trees. Based on results from 15

trees (three trees from each of five states) the sapwood was

, more decay susceptible than the heartwood. There were no

significant gradients in decay resistance of the heartwood

associated with radial or longitudinal position in the trunk.

The heartwood of individual trees from the same site varied

significantly in decay resistance. This variation is

attributed mainly to genetic variability. Similarities in

heartwood decay resistance between trees collected in

different states suggest that site is not a major factor in

determining decay resistance.

Considering that black walnut is one of species has shown that decay resistance

Our most desirablre and valuable timber decreases progressively from the outer

species, there is little information on the heartwood to the pith. Decay resistance of

chemistry and durability of its heartwood, the outer heartwood decreases progressively

Almost all available material on walnut from the base of the tree upward, whereas the

describes the heartwood as decay resistant opposite is true for inner heartwood. Varia-

(Scheffer and Cowling, 1966), but pnblished tion in decay resistance between individual

data to substantiate this claim could not be black walnut trees or within individual trees

located, has not been investigated.

Individual trees of the same species may As walnut wood is used in products that

vary considerably in their decay resistance are expected to last for years or even dec-

(Scheffer and Cowling, 1966). This variation ades, the resistance of this wood to microbial

mainly is Controlled genetically rather than deterioration of importance even though the

by differences among sites on which the trees wood is seldom used under conditions conducive

'developed. Decay resistance also varies among to decay. How durable is black walnut

different parts of the same tree (Scheffer and heartwood and does this durability vary in the

• Cowl ing_ 1966). Research with other tree different geographical areas that it inhabits?

Is the heartwood in one part of the tree more

i | . . durable than in another part of the tree?

Will heartwood from fast-growing, intensively

' Ipaper presented at the 12th Annual managed trees be as durable as that from

Meeting bf the Walnut Council, Purdue naturally-occurring trees? The purpose of

University, West Lafayette, Indiana, August this research was to collect data which would

9-14, 1981. Michigan Agricultural Experiment answer these questions.

Station Journal Article No. 10175. This

research was supported by a grant from the

U.S. Forest Service. The author thanks Helen MATERIALS AND METHODS

Haffei, Terry Kamps and Carla Thomas for

technical assistance and Linda Swain and Scott To determine the effect of growth rate of

Eisensmith for statistical assistance, walnut on decay resistance, four trees with

2professor, Departments of Botany & different rates of growth were sampled.

Plant Pathology and Forestry, Michigan State Blocks 2 cm 3 were cut 5 m above ground from

University, East Lansing, Michigan 48824. logs harvested in Lansing, Michigan. The

•

12 -.
.

number of annual rings per cm was determined thickness were cut. Blocks were cut from 

for each block. Blocks were dried at 45°C for radii so that there would be 4 sapwood, 

one week, weighed, steamed for 15 minutes, outer heartwood, 4 middle heartwood and 

placed aseptically into decay chambers con- inner heartwood blocks (fig. I). Blocks 

raining Coriolus vesicolor or Poria placenta a given cylinder were used for one of th

for eight weeks (McNabb, 1958), removed, dried fungi (P. placenta, C. versicolor or

at 80°C for one week, and reweighed. Ten Schizoph--Fllum commune) or as control bloc

blocks were used from each tree, each wood The agar-block method (McNabb, 1958) with 

type and for each decay fungus, exposure period of I0 weeks was used to

determine rates of decay. Data were obtai

from approximately 3,000 blocks which wer

analyzed statistically.

0

RESULTS

° _ Top Growth and decay rates of black waln

shown in Table I. Tree 1 was a consisten

, fast growing tree, tree 4 a consistently 

growing tree and trees 2 and 3 were growi

--s,p,o_ relative!ly fast when the heartwood tissue 

M_I, --OuteH,.,_ood formed but recent growth was only one-hal

_- Middle Hea Mwood

• i I----InnerHeartwood that of earlier growth. Analysis of vari

II revealed significant differences in decay

__ resistance between trees for a given fun

-_ !:i!_:_. but these differences were not correlated 

growth rate (Table I).

httom Table l.--Growth and decay rate of slow- 

fast-growing black walnut collected in

Michigan

Weight lo

Average no. % dry wei

• Wood type and of annual Poria C

tree number rings/cm placenta ve

Heartwood I 1.8 21.4 

Figure l.--Diagram of sampling procedure used 2 3.0 11.6 

in collecting blocks for decay studies. 3 3.7 17.4 

Samples were collected from the top, middle 4 6.5 16.1 

and bottom of the tree and, at each of these

positions, from the sapwood and heartwood as Sapwood i 2.0 29.3 

illustrated. 2 6.5 34.4 

, 3 7.0 31.1 

4 7.0 33.4 

To determine the variability in decay

resistance throughout the range of black

walnut and from different locations within a

tree, three mature walnut trees were collected To answer the question 'Does the du

' from five states: Kansas, Kentucky, Michigan, ity of the outer heartwood differ from t

Pennsylvania and Wisconsin. All trees were inner heartwood?' an analysis of variance 

•dissected within one week of cutting except run on the data for each state for each 

for the trees from Pennsylvania which were three fungi. Data for all three trees a

.... stored for 5 weeks at O°C before sampling, all three locations within the tree (top

Blocks 1.9 cm 3 were cut from three vertical middle, and bottom) were lumped for anal

• positions from each tree: 0.5-I.0# 5-6 and As expected, the sapwood was consistently 

9-10 m above ground line. All samples had to decay susceptible than the heartwood. H

be free from decay and defect; therefore, ever, outer, middle and inner heartwood 

precise sample heights were impossible. At not differ significantly from one another 

each vertical position cylinders 1.9 cm in their rates of decay (fig. 2).
CORIOLUSVERSICOLOR CORIOLUSVERSICOLOR

4O 14

37.9

3S 12

..

30 (n 10

u) u)

v) O O _,

_'- 25 I.-

z

_O __ 8

W ' tM

3 •

"-20

0 o< 5.9

o_ m 6

W 0 5.4

o <

° < 15 m 4.6

J _ uJ m >

> ' < 4 <

10

0.2 2

" 5 4.5 5.1

Top Middle . Bottom

Sapwood Outer Middle Inner

Heartwood Heartwood Heartwood

Figure 3.--Decay rates of black walnut

heartwood collected from the top, middle and

bottom of the trees when exposed to Coriolus

versicolor for I0 weeks.

Figure 2.--Decay rates of black walnut sapwood

and heartwood when exposed to Coriolus

versicolor for I0 weeks. Decay rates for PORI______APLACENTA

Poria placenta and Schizophyllum commune 

showed a similar pattern. 16.6

• " 16

A similar procedure was used to determine 14

if the sapwood or heartwood from the top, _ 12

middle and bottom of the trees differed in O 1'2 "31

their resistance to decay. Rates of decay for

the sapwood did not differ significantly with

position in the tree. Generally, the same _ 10 9.6 

pattern was true for the heartwood (fig. 3). =,

However, P. placenta was capable of causing a _ 8.1

faster rate of decay of bottom heartwood "-"

• compared to heartwood from the top for trees _ 6.8 7.1

collected from Pennsylvania and Kentucky _ i

(fig. 4). _ 

1

' o KEN TucKY PENNSYLVAN,_

Figure 4.--Decay rates of black walnut

heartwood collected from Kentucky and

Pennsylvania when exposed to Poria placenta

i_ for I0 weeks. •

14
The decay rates of the heartwood for each

tree were compared for trees collected in each

state to determine if durability varied KANSAS WALNUTTREES

between trees on the same site. Decay rates

were not significantly different between trees CORIOLUS VERSICOLOR

for either _C" versicolor or _P. placenta for

trees collected in Michigan, Kentucky or 8 7.65

Pennsylvania However, there were differences mu)

between trees collected in Kansas and O 7

_J

Wisconsin. The heartwood from tree no. 2 from _.

Kansas was significantly more decay resistant == 6 5.85

when exposed to either C versicolor or P _-" m." []

lacen figs. ta "5-5t).han either trees no. 1 or 3 _ 5

z

m 4 3.8

0

o or

UJ

18,-- KANSAS WALNUT TREES eL 3

17 | PORIA PLACENTA Om 

< 2

16 or uJ

15 15.05 > 1

•

w 14

v) 0 1 2 3

0 13 .J

)" 12 TREE .r

_0 11 iJJ

" • 10

z 9

uJ

O 8 Figure 6.--Decay rates of black walnut 

or wood collected from three trees in K

-w

eL 7 and exposed to Coriolus versicolor f

_u

(_ 6 weeks.

< 5.95

or 6

uJ

• 4 " The last comparison was between s

3 i.e. does the durability vary from one 

2 1.65 to another. Rates of decay for heartwo

all radii, positions and trees were lu

1 each state. An analysis of variance w

0 conducted to determine differences bet

1 2 3 states. Heartwood from trees collected 

• - TREE Kentucky and Pennsylvania decayed at a 

ficantly faster rate than heartwood co

Figure 5.--Decay rates of black walnut heart- in Kansas, Wisconsin and Michigan when 

' Wood collected from three trees in Kansas to C. versicolor (fig. 7). However, t

and exposed to C_oriolus versicolor for I0 were-no Significant differences in dec

weeks, between states when the heartwood was 

to P. placenta (fig. 8).

. 
°

DISCUSSION

17 -CORIOLUS VERSlCOLOR

16 The heartwood from fast-growing

15 plantation trees should be just as decay resistant as the heartwood from slower-growing

0_ 14 trees in natural stands, according to evidence

0_ 13.07 presented above. Since wood durability is

O_J 13 directly correlated with the amount and type

_- 12 of heartwood extractives formed when sapwood

3: is transferred into heartwood it appears -_ " 11

,31 heartwood formation is basically the same in

3= 10 fast and slow-growing trees. This has

_- additional significance because heartwood

z 9 8.42 uJ . extractives give walnut its distinctive color

Oe_ .8 and influence its workability.

m 7

Q. .

+ W +6 5.84 The fact that the heartwood did not vary

(9 5.39 5.37 in decay resistance radially differs from

5 previous reports (Scheffer and Cowling, 1966) e_

uJ Radial gradients in decay resistance are the

• 4

result of chemi-cal alteration (polymeriza3 tions) of the toxic components as the

2 heartwood ages. This explains, at least in

I part, why we find hollow trees in nature.

0 My results with black walnut would

KAN. WlSC. MICH. KENT. PENN. suggest that the compounds responsible for

decay resistance do not polymerize as the

Figure 7.--Decay rates of black walnut heart- heartwood ages. However, not enough is known

• wood col.lected from five states and exposed about the chemistry of decay resistance in

to Coriolus versicolor for I0 weeks, walnut to provide a conclusive explanation of

why there seems to be little chemical

alteration as the heartwood ages. The

17- PORIA PLACENTA explanation of this phenomenon of consistent

16- decay resistance will have to await further 

15 - investigation.

• 14--

0_ While variation in decay resistance of

"0_ the heartwood within individual trees differed

0 13-

_j from previous studies, variation in decay

_. 12- 11 49 11.35 resistance between individual trees and 3:

.(9 11 between trees from different sites was similar

,%1 to previous reports (Scheffer and Cowling,

3: 10 9.06 9.31 1966). It is known that individual trees of

_Z 9 the same species may vary considerably in

l,U their decay resistance and that this variation 0 8 7.55

== is primarily genetically controlled. The data

. , uJ 7 presented support these previous conclusions. I

m 6 If significant variations in decay resistance

(9 occur between trees from a given state (e.g.

< 5

tree 2 from Kansas, figs. 5-6), the variation

I , uJ 4 is most likely due to genetic differences and

I • it should not be attributed to site

< 3 differences. All trees from one state were

2 collected from the same site. On the other

1 hand, there were major site differences 

0 between states, yet decay resistance as

KAN. WlSC. MICH. KENT. PENN." measured by _P" placenta did not differ

significantly between states. Even though

Figure 8.--Decay rates of black walnut heart- there were some differences in decay rates

_, wood collected from five states and exposed caused by C. versicolor, trees from Kansas,

to Poria placenta for I0 weeks. Wisconsin and Michigan were remarkably similar

16

, 
° •

even though the sites of collection were not

similar.

Additional collection of trees will be

made during the coming year in Indiana,

= Illinois, Mississippi and North Carolina.

Hopefully, this additional sampling will help

clarify variations in decay resistance of

black walnut throughout its range.

LITERATURE CITED

Scheffer, T. C., and E. B. Cowling. 1966.

Natural resistance of wood to microbial

deterioration. Annu. Rev. Phytopathol.

4:147-170.

°

' 
°

|

EPIDEMIOLOGY OF BUTTERNUT CANKER1

N. A. Tisserat and J o E. Kuntz 2

i

Spores of Sirococcus clavigignenti-juglandacearum, the

causal fungus of butternut canker, were liberated only during

rainfall by the action of rain splash impaction on the spore

matrix of fruiting pycnidia. During rainfall, conidia were

trapped on rotorod samplers up to 30 m from cankered trees,

although observation of natural spread indicated some spores

probably travel greater distances. A high concentration of

spores were washed down the tree trunk from branch cankers in

stem-flow water. Infection and canker development following

artificial inoculation occurred throughout the sunener on

butternuts in the field. Natural infection of potted

seedlings placed under diseased trees occurred from late July

to October. The fungus continued to sporulate heavily on

recently killed, cankered trees that remained standing or that

were felled. These trees served as potential inoculum

re s ervo ir s •

\

INTRODUCTION causal organism has been identified as tke

imperfect fungus, Sirococcus clavigignentiButternut canker, first reported in juglandacearum (Nair et al., 1979).

Wisconsin in 1967 (Renlund, 1971), is the

most serious disease of butternut (Juglans A better understanding of the

cinerea L.). Since the first report, the epidemiology of butternut canker, especially 

disease has been found throughout the with regards to environmental conditions

-natural range of butternut in eastern United favorable for sporulation, spore dispersal,

States (Anderson and LaHadeline, 1977) and and infection, is needed before

threatens to eliminate this beautiful and silvicultural control measures can be

valuable hardwood in many areas of the recommended. The objectives of our research

country (Nicholls, 1979). The disease is were 1) to identify environmental conditions

especially severe in southern Wisconsin favorable for sporulation and dispersal of

where some survey plots had a disease the pathogen; 2) to examine the rate at

incidence of 80% (Prey and Kuntz, 1981). which branch and stem cankers develop; and

Symptoms of the disease include branch- 3) to evaluate the potential of dead or

mortality and multiple cankering of both the dying butternuts to serve as inoculum

• main stem and the buttress roots. The sources.

, , ,, ,,,,

Spore Liberation and Dispersal

1PaPer presented at the 1981 Joint

' Meeting of Walnut Council/Northern Nut Seasonal spore release was studied in

, Growers Association. Purdue University, pockets of diseased butternuts in the

West Lafayette, Indiana, Aug. 9-14, 1981. University of Wisconsin Arboretum, Madison,

2Graduate Research Assistant and during 1979 and 1980. Vaseline-coated

i Professor, respectively. Departments of microscope slides were placed beneath

Plant Pathology and Forestry, University of cankered trees and removed at daily or

Wisconsin-Madison, 53706. weekly intervals. The number of spores per

interval was determined by counting all S. • _=.

clavigignenti-juglandacearum spores in 20

°

18 •
random light microscopic fields at X430. water was adjusted to the original a

Spores of the fungus were liberated from stem runoff water in each sample.

cankered trees from mid-April through Concentrations greater than I00 spore

October in both years, but only during those runoff water were common and occasion

days in which there was measurable concentrations higher than I0,000 sp

rainfall. Table I indicates results for the were recorded (Table 2). Spores in

7-day period of June 15-21, 1979. Slides rainwater flowing down the stem can 

placed beneath trees directly after rainfall lodged in lenticels, bark cracks, and 

or during periods of relative humidity where they may germinate and start n

greater than 90% did not have spores infections. This may explain the mu

deposited on them. Spore collection on cankering typical of diseased buttern

rotorod and Hirst spore traps also showed especially on the lower trunk and bu

that liberation of conidia only occurred roots. Cankers of various ages and s

durin_ rainfall, commonly occur on the same tree.

Table I Number of spores trapped daily on Table 2 Mean number of S. clavi_i_ne

vaseline-coated microscope slides juglandacearum spores/ml in

placed beneath a cankered butternut stem-runoff water from two 

tree. cankered butternut trees fo

rainfall dates in 1980.

June 1979

15 16 17 18 19 20 21

....... Number of spores/ml stem-runoff 

Rainfall (inches) 0 0 .13 0 .60 .I0 0

Number of spores I/ 0 0 186 0 275 134 0 I 6/27/80 7/4/80 7

I/ Total spores on 20 fields at X430. Tree I 5.2 x 102 2.3 x 102 2.

-- Tree 2 1.3 x 104 2.2 x 104 1.

The spores of S. clavigignenti- _I/ Mean of two samples, five counts 

juglandacearum are tightly bound in a sample.

gelatinous matrix as they are extruded from

pycnidia embedded in stromatic tissue

beneath loosening outer bark, and are not

easily removed, even under windy One of the unique symptoms of th

conditions. Preliminary'experiments with is the formation of basal stem and 

blowing air, mist, and water droplets proved root cankers. Basal cankers may ext

that rain splash impaction on the matrix is the soil line to a depth of 30 cm, b

needed for liberation of the spores to progress laterally for only a few 

(Tisserat et al., m==- 1981). roots before marginal callus forms. 

girdling of the cambial regional at 

Many of the spores liberated from branch of the tree by multiple cankers is o

and stem cankers during rainfall are washed cause of tree death, rather than gir

down the tree trunk in stem flow water. The occurring higher on the trunk.

quantity of conidia in stem runoff was

determined by placing water-tight funnel Buttress roots also may become h

traps around the main trunk of two cankered cankered. Roots exposed at the soil 

trees (dbh 20 cm) at a height of I meter, been found to be cankered up to 2 m 

After periods of rainfall, stem runoff trunk, but cankers on roots below th

collected in the funnels was siphoned into I line have not been detected. The po

liter plastic bottles. The runoff water of tree-to-tree spread of the fungus 

t then was centrifuged at 8,000 g for 20 root grafts is being studied.

minutes to sediment the S. clavi_ignentijuglandacearum conidia and other The spores of S. clavigignentiparticulates. The sediment was resuspended _uglandacearum also can be carried f

in a mixture (5:1 v:v) of distilled water to tree in rainsplash droplets result

and trypan blue in lacto-phenol (-for easier new infections. Spore dispersal gra

identification of the spores). The from an isolated pocket of diseased 

concentration of S. clavi_i_nenti- were determined by placing rotorod s

juglandacearum spores in the suspension was at 7.5 m intervals to 30 m downwind 

determined with a light-field trees. The number of spores impacted 

haemacytometer, and the number of spores/ml traps during rainfall was plotted ag
|

! distance the traps were placed from the not eliminate infection since it is not known

inoculum source (Fig. I). Spore numbers whether insects or other vectors also aid in

decreased rapidly as the distance increased spore dissemination.

from the inoculum source, but some conidia

were trapped at 30 m. The curve is hollow To determine environmental conditions

Shaped, similar to curves of many airborne favorable for infection, groups of 30 potted

fungal spore and pollen dispersal gradients, butternut seedlings were placed among cankered

trees in the woods at two-week intervals (May _

" through October, 1980). After each two-week

B00 " I I period, the respective seedlings were brought

back to the greenhouse and observed for

• symptoms of butternut canker. Most naturally

invected seedlings showed initial symptoms

500-° -- within 2 weeks. Nevertheless, all seedlings

were held in the greenhouse to observe canker

, development.

400 W None of the seedlings placed in the woods

_=O prior to August I became diseased Some

seedlings placed out from August 1 through

October became infected and subsequently were

b'300 O -- killed by the fungus Leaf scars appeared to

be the major infection court, but lesions also

developed at lenticels and at the root collar

on several trees. Initial symptoms appeared

200 -- as small black necrotic flecks which rapidly expanded to dark brown ellipitical lesions.

Bark cracking was commonly observed at the

• lesions, followed by an inky exudate from the

I00 -- opening. The root collar or basal stem

lesions progressed into the root itself

causing black irregular lesions on the main

-_o_ o o tap root of young seedlings.

o [ I I Early in the summer, rainfall was sparse

O 75 15 225 30 and the weather was hot and dry. In contrast,

frequent heavy rainfalls occurred from

DISTANCE FROM INOCULUM SOURCE (m) mid-July through September. Natural infection

of the potted seedlings occurred only during

the late-summer rainy period. Rainfall _nd

• high relative humidity are optimal for spore

FigUre I. Average number of S. clavi_i_nenti- dispersal and infection by S. clavigi_nentijuglandacearum spores caught during five juglandacearum (Kuntz et al., 1979). The

rainfall periods (1980) on rotorod traps results also support the hypothesis that a

positioned up to 30 m from a diseased pocket major infection period is in the late summer

• of butternuts, and early fall. Fresh leaf scars during this

time create a suitable infection court for the

Spore dispersal curves may be useful in fungus (Kuntz et al., 1979).

determining eradication distances needed to

' prevent the influx of inoculum into healthy Canker development

, butte_ut stands. Similar curves have been

i used to define the zone for Ribes eradication Canker development was studied in a

in white pine blister rust control programs plantation of butternuts at the University of

(Van Arsdel, 1961). Based on our present Wisconsin Arlington Experimental Farm. Ten

results, we recommend that all diseased trees were inoculated bi-weekly from May I

butternuts should be cut, removed, and through October I0, 1980, by puncturing three

destroyed for at least a 60 m radius from a leaf scars on a healthy branch with a

healthy butternut stand or black walnut dissecting needle and placing approximately

plantation. Butternuts and black walnuts .05 ml of a spore suspension (I0° Sirococcus

should not be planted under or near diseased spores/ml water) on the wound. Cankers formed

butternuts. While these control measures on branches after all inoculation dates. Two

should reduce the amount of inoculum reaching types of canker development were noted. In

healthy butternuts and black walnuts, they may the first type, lesions appeared discrete,

"20
°

sunken, and were bounded by a callus layer, traveling in aerosols, or both may be i

Cankers of this type progressed slowly and the

branches were still alive after six months. Infection and canker development af

In the second type, fungus invasion and artificial inoculation can occur at any 

colonization of the branch after inoculation during the summer. Twigs and small bra

occurred rapidly. Some branches were killed can be killed in as little as one month

and hyphal pegs were produced in as little as 1980, a major infection of noninoculated

. one month after inoculation. No distinct potted seedlings placed under diseased 

canker margin was noted on these branches, occurred during rainy, humid conditions 

The reason for the difference in reaction August I through October. These dates

types _ is not known, but it was noted that corresponded with senescence and leaf d

those inoculated branches that died rapidly Fresh leaf scars are known to be infecti

were partially shaded or were located on the courts of the fungus. From such late s

lower portion of the tree. The shaded and fall infections, cankers appear and

branches may have been physiologically develop rapidly the following spring.

stressed and were more susceptible to

colonization by the fungus. In other cases, The fungus sporulates heavily on re

no cankers developed until the spring killed or cankered trees, either standi

following inoculation in late summer, felled, which serve as a potential inoc

reservior. In order to prevent inoculum

Inoculum source buildup, dead or dying trees should be 

from the site. Walnuts and butternuts 

To determine whether felled trees could not be planted under or near cankered t

serve as important inoculum sources, five

heavily cankered trees, 8-11 cm in diameter

and 8-11 m tall, were cut and placed on the LITERATURE CITED

forest floor (February , 1980). By June I,

• 1980, all cut trees showed evidence of Anderson, R. L., and LaMadeline, L. A. 

extensive colonization and sporulation by S..=. The distribution of butternut decli

clavi_i_nenti-juglandacearum, even beyond the the eastern United States. U. S. D

originial canker margins. Large quantities of Agric. For. Serv. Northeast Area S

spores were produced. Therefore, infected and Private For Surv. Rep. S-2-77. 

trees should be removed from the site to

prevent inoculum buildup. Present studies Kuntz, J. E., Prey, A. J., Jutte, S., a

seek to determine if basal stem girdling or Nair, V.M.G. 1979. The etiology,

• poisoning of diseased trees will hasten bark distribution, epidemiology, histolog

shedding and tree drying and thereby reduce impact of butternut canker in Wisco

sporulation by the fungus. Pages 69-72, in Walnut Insects and

• Diseases. Workshop Proc. U.S. Dept

Agric. For. Serv. Gen. Tech. Rept. 

CONCLUS ION I00 p.

Spores of the fungus Sirococcus Nair, V. M. G., Kostichka, C. J., and K

clavi_ignenti-juglandacearum are liberated J.E.. 1979. Sirococcus clavigigne

during rainfall by rain splash impaction. A juglandacearum: An undescribed spe

• high concentration of spores from cankered causing canker on butternut. Mycol

branches are washed down the tree trunk via 71:64]-646.

Stemflow water, leading to multiple infections

of the same tree. The multiple cankers Nicholls, T. H. 1979. Butternut canke

eventually girdle the cambium resulting in the Pages 73-82, in Walnut Insects and

death of the tree. The girdling often occurs Diseases. Workshop Proc. U.S. Dept

at the base of the tree (at the soil line) Agric. For. Serv. Gen. Tech. Rept. 

rather than higher on the trunk. I00 p.

Short distance dispersal of inoculum Prey, A. J., and Kuntz, J. E.. 1981.

Occurs when splash droplets containing spores Distribution and impact of butternut

are windblown from tree to tree. Spores have canker in Wisconsin. Proc. Joint M

been trapped 30 m from a diseased pocket of Walnut Council and Northern Nut Gro

butternuts during rainfall, although Assoc., Aug. 9-14, 1978, Purdue Uni

observations of natural spread among butternut Lafayette, IN. (To be published).

plantings indicate spores travel even greater

distances. Mechanisms of long distance

dispersal of the fungus are not known but it

has been postulated that vectors, spores
°

Renlund, D.W. 1971. Forest pest conditions

in Wisconsin, WI. Dept. Nat. Resour. Ann.

Rep. i971. 53 p.

Tisserat, N., Nicholls, T. H., and Kuntz, J.

E. 1981. Spore liberation and dispersal

of Sirococcus clavigi_nent i-_ ugl andacearum.

(Abst.) Phytopat_ology 71:261.

Van A rsdel, E.P. 1961. Growing white pine

in the Lake States to avoid blister rust.

U. S. Dept. Agric. For. Serv. Lake States

Exp. Stat. Pap. 92. II p.

i

!

!

4

i

!

,!

22 •

°
o

°

.. THE DISTRIBUTION AND IMPACT OF BUTTERNUT CANKER

IN WISCONSIN 1

A. J. Prey and J. E. Kuntz 2

Widespread dying of butternut (Juglans cinerea L.) was

, reported in 1967 in southwestern Wisconsin. Since then, this

canker-dieback disease, incited by the fungus Sirococcus

c lavigignenti-juglandacearum Nair e.._t al, has been found

• throughout eastern U.S.A. Diagnostic symptoms have been

described, the disease cycle clarified, and the host range

" expanded. Current studies concern disease epidemiology and

." possible disease resistance in butternut and other Juglans

species.

INTRODUCTION Minnesota, Ohio, and Wisconsin.

Widespread dying of butternut (Juglans An initial examination of diseased 

• • cinerea L.) first was reported in indicated that Melanconium oblongum Be

southwestern Wisconsin in 1967 (Camp, 1967; associated with branch dieback and frui

Renlund, 1971). The number and extent of abundantly on dead branches. However,

the diseased areas and the deterioration of distinct cankers also were present on 

the dead trees indicated that the disease living branches and trunks. In contrast,

had been active for several years (Kuntz e__t Graves description in 1923 (Graves, 19

al., 1977). Canker-dieback since has been the Melanconis disease in Connecticut

• found throughout the range of butternut in specifically stated that no well marked

eastern United States (Anderson, 1978; USDA, lesions or cankers were found with the

1976; USDA, 1977a; USDA, 1977b)and the Melanconis dieback. Moreover, recent

fungus pathogen has been isolated from inoculations of young butternut seedlings

diseased specimens collected in Indiana, and saplings with M_. oblongum failed t

Illinois, Iowa, Michigan, Missouri, incite either branch or stem cankers. 

_ _ fungus is considered a weak parasite tt

needs a stressed host to permit its

Ipaper presented at the 1981 Joint development (Hepting, 1971). Melanconi

Meeting of Walnut Council/Northern Nut dieback also was reported on black waln

Growers Association. Purdue University, J. nigra L., and other Juglans species

West Lafayette, Indiana, Aug. 9-14, 1981. _Graves, 1923).

2Forest Pathologist, Forest Pest

Control Section, Bureau of Forestry, Diagnostic symptoms of butternut c

Wisconsin Department of Natural Resources, include discrete, elliptical cankers o

, Madison, Wisconsin, 53711, and Professor, bark and wood of twigs, branches, stems

Departments of Plant Pathology and Forestry, even exposed buttress roots (Kuntz et 

University of Wisconsin, Madison, Wisconsin, 1977; Kuntz et al., 1979; Nicholls et 

53706. Supported in part by U.S.D.A. Forest 1979). Young cankers commonly originate 

Service, North Central Forest Experiment leaf scars, other natural openings such 

Station, Cooperative Aid Agreements No. lenticels, buds, bark wounds including

13-405 and No. 13-417. The authors express insect wounds, natural bark cracks, an

• appreciation to Robert L. Anders'on, occasionally at points apparently free 

Pathologist, S. and P.F., U.S.D.A. Forest any injury. Older cankers on trunks a

Service, for assistance in disease surveys, large, open or partly covered by shredd

• 
bark, vertically oriented, and perennial, matrix, or a spore suspension in water

Cankers Of different ages and sizes commonly incited lesions on midribs and petioles of

occur on the same tree. Some stem cankers leaves and cankers on branches, stems, and

have persisted for several years as roots of butternut and black walnut

evidenced by the repeated layers of annual seedlings and saplings (Kuntz and Prey,

callus and by differential growth-ring 1978). Both hyphal pegs and sporulating

counts. In many cases, their origin is pycnidia frequently formed on the thin

unknown. However, adventitious buds, dead fungus stroma beneath loosening outer bark

branches, and branch stubs are present in of inoculated seedlings and saplings.

the centers of some cankers.

Peeling the bark from branches and MATERIAL AND METHODS

trunks may disclose dark brown to black

inner bark and wood of undetected cankers. Wisconsin's 1968 Timber Resource Survey

Older cankers often bear shredded bark (Spencer and Thorne, 1972) was used to

ounderlain with blackened wood, may be locate forest inventory plots containing

bordered by repeated callus layers, and butternut. A maximum of five one-fifth-acre

frequently coalesce to girdle branches and plots per county was selected and examined

stems. Branch suckers and trunk sprouts by U. S. Forest Service and WDNR field crews

often develop below the.girdled portion, are in 1976. Where possible, up to 50 butternut

readily infected, and die shortly trees were examined on or adjacent to each

thereafter. Sprouts are infected commonly plot. Data were recorded as to general tree

in the fall through leaf scars and small, health, canker incidence, limb or top

irregular lesions or large dark areas dieback, and death from cankering or other

develop rapidly early the following spring, causes. Trees also were grouped into

Infection of lenticels result in tiny, poletimber (< I0 inches or 25 cm dbh) and

round, chocolate brown lesions of the bark. sawtimber (> I0 inches or 25 cm dbh)

• Initially only the outer bark is infected, classes. Dying or cankered branches were

but soon the wood is invaded (Jutte et al., collected from diseased trees in each plot.

1978). On older trees, in the spring and Isolations for possible pathogens (Kuntz ==et.=.

early summer, an inky black exudate issues al., 1977; Nicholls ==. et.=..al., ===. 1979) were made

from canker fissures; later in summer, sooty in the laboratory on acidified potato

black patches remain. Often the exudate dextrose agar (PDA) medium.

also indicates initial infections and

incipient cankers. Eventually, infected

• trees die. " RESULTS

It is now known (Jutte et al., 1978; A total of 2,882 butternut trees were

Nair et al., 1978; Nair et al., 1979) that examined on or adjacent to 83 study plots .in

under the outer bark, the causal fungus 33 counties. Of all trees examined, 44%

forms a thin, black mycelial stroma from appeared healthy, 30.9% were stem-cankered,

which arise hyphal pegs and pycnidia. 42.1% exhibited some degree of branch

Spores are extruded either in sticky masses cankering and dieback, and 8.7% already were

or as fine, hairlike cirri. Spores are dead. Of all trees examined, 61.8% were

dispersed by rain or mist and disseminated by classed as poles and 38.2% were sawtimber

wind (Nicholls, 1979; Tisserat et al., Of the poles, 34.5% were cankered; of the

1981). The role of insects and other sawtimber, 25.1% were cankered.

possible vectors remains unknown.

In several counties in northeastern

In 1969, studies were initiated on the Wisconsin, no cankered trees were

etiology and epidemiology of butternut discovered. In contrast, in southwestern

canker (Kuntz et-==.. =-==. al., 1979). The causal Wisconsin counties, as many as 80% of the

fungus, coded BN-5 and identified as a new butternuts were cankered and 32% were dead.

Sirococcus species (Nair et al, 1978; Nair The fungus pathogen was isolated from most

et ai., 1979_, was readily isolated in pure cankers collected in western and

culture on common nutrient media from both southwestern Wisconsin but not from trees in

bark and wood. The pathogen grew best at eastern Wisconsin. In addition, the fungus

24-28 C in light or dark; formed was isolated from cankered butternuts in

characteristic mycelial colonies, hyphal Iowa, Michigan, Minnesota, and Wisconsin.

pegs, and pycnidia in culture; and Meanwhile, M. oblon_um was found on many

sporulated profusely, especially when dead branches throughout the range of

growing on thin malt agar. Inoculations of butternuts in Wisconsin.

fresh wounds with mycelium, the spore

4_4
Cankers were found on all woody parts of cankered trees (Orchard, 1981). Wheth

diseased butternuts. Cankers developed on such trees are "disease escapes" or ar

trees growing on many different soils and resistant to attack by the fungus path

sites, including dry, infertile ridgetops is unknown. Branch and stem cankers 

with shallow soils as well as in moist, detected infrequently on black walnuts 

fertile bottom lands with deep soil. Trees woodlands even though artificial

° of all ages and sizes growing in mixed and inoculations have incited cankers on w

relatively pure stands were diseased, seedlings and saplings. Most cankers

Infected trees occurred either in local develop slowly, forming marginal callu

pockets or over fairly extensive areas. In However, infected branches frequently 

• these disease areas, occasional butternuts without forming distinct cankers.

appeared canker-free and healthy. So far, Hopefully, most black walnuts will rem

small branch and Sotem cankers have been canker-free. Otherwise, the increasin

detected on a few black walnuts growing in number of walnut plantings in the Midw

mixed stands with severely infected would be in grave danger.

butternuts. The fungus pathogen was

isolated from cankered walnuts. Walnut The formulation of effective contr

isolates, wound-inoculated int 9 butternut measures must await further information

and walnut seedlings and saplings, incited certain silvicultural controls already

typical perennial branch and stem cankers, indicated. Meanwhile, do not plant w

Especially with black walnuts, many or butternuts under or near infected

inoculated branches died without forming butternuts. Canker distribution and 

distinct cankers. The fungus has been in Wisconsin has been determined, the 

reisolated repeatedly during a 6-year period fungus has been identified, and its m

from perennial cankers on walnut stems, spread have been clarified. Present

research seeks to clarify conditions

favoring infection and disease develop

DISCUSSION (Kuntz et al., 1979).

Butternut occurs throughout the northern

two-thirds of eastern United States under a LITERATURE CITED

wide range of soils and climatic conditions

(Schroeder, 1972). Although it grows best Anderson, R. L., and L. A. LaMadeleine

on rich, deep moist soil, butternuts grow 1978. The distribution of buttern

faster than do walnuts on dry, rocky soil. decline in eastern United States.

• Survey Report S-3-78. U.S. Dept. 

Although, butternut is a minor species For. Serv., Northeast Area State 

in Wisconsin (18.3 million cu. ft. net Private Forestry, Broomall, PA. 

volume of growing stock) (Spencer and

Thorne, 1972), select butternut lumber is Camp, R. 1967. Personal communication 

second only to walnut in economic value correspondence.

(Peterson, 1977). In 1967, 343,000 cu. ft.

of butternut were harvested, compared to Graves, A. H. 1923. The Melanconis 

292,000 cu. ft. of black walnut (Spencer and of butternut Ju_lans cinerea L.

Thorne, 1972). In fact, Wisconsin ranks Phytopathology 13:411-435.

second in the'amount of butternut found in Hepting, G. H. 1971. Diseases of Fo

the United States and is a major producer of and Shade Trees of the United Sta

butternut lumber, used primarily for U.S. Dept. Agric., For. Serv. Han

furniture, cabinets, and other fine woodwork 386. 658 p.

(Schroeder, 1972; Spencer and Thorne, 1972).

Jutte, S. M., J. E. Kuntz, and R. N. 

In the past, butternut has suffered from 1978. Histology of butternut can

few diseases (Hepting, 1971; USDA, 1960) or (Abstr. 268) Proc. 70th Ann. Mtg. 

insect pests (Schroeder, 1972). Now, Phytopath. Soc., Phytopath. News.

however, it appears that the canker is 12(9).

potential threat to butternut throughout its

natural range (Anderson, 1978). Meanwhile, Kuntz, J. E., and A. J. Prey. 1978.

little or no regeneration of butternut has Etiology, distribution, and impac

occurred in disease areas. Both sprouts and butternut canker in eastern U.S.A

seedling trees are infected and rapidly (Abstr. 109) Proc. 3rd Intl. Congr

killed. Fortunately, an occasional Plant Pathology, Munich.

butternut remains healthy even though

growing in the midst of severely
.

Kuntz, J E., A. J. Prey, B. Ambuel, and E. For. Serv. Resource Bull. NC-15). 80 p.

Sarki s • 1977. The et£oiogy and

epidemiology of butternut canker. Tisserat, N., T. H. Nicholls, and J. E.

(Abstr. 10) Proc. 69th Ann. Mtg. Am. Kuntz, 1981. Spore liberation and

Phytopathol. Soc., p. 84. dispersal of Sirococcus

clavigignenti-juglandacearum (Abstr.)

Kuntz; J. E., A. J. Prey, S. Jutte, and Phytopathology 71:261.

V.M.G. Nair. 1979. The etiology,

distribution, epidemiology, and impact U.S. Department of Agriculture. 1960.

of butternut canker in Wisconsin. Pages Index of Plant Diseases in the United

69-72 .in=_=. Walnut Insects and Diseases. States. Agric. Handb. No. 165. 531 p.

Workshop Proceedings, June 13-14, 1978,

Carbondale, IL. U.S. Dept. of Agric. U.S. Department of Agriculture. Forest

For. Serv., Gen. Tech. Rep. NC-52. 100 Service. North Central Forest

p. Experiment Station. 1977a. Butternut

decline, progress report 1. 4 p. Mimeo.

Nair, V. M. G., C. J. Kostichka, and J. E.

Kuntz. 1978. A new species of , U.S. Department of Agriculture. Forest

Sirococcus causing canker of butternut Service. North Central Forest

in eastern U.S.A. ( Abstr. 127). Proc. Experiment Station. 1977b. Butternut

3rd Intl. Congress of Plant Pathology, canker, progress report 2. 4 p. Mimeo.

"Munich.

U. S. Department of Agriculture. Forest

Nair, V. M. G., C. J. Kostichka, and J.E. Service. 1976. Butternut Decline.

Kuntz. 1979. Sirococcus clavigignenti- Pest Alert. U. S. Government Printing

juglandacearum: an undescribed species Office. #653-647. 1 p.

causing canker on butternut. -Mycologia

LXX1:641-646.

Nicholls, T. H. 1979. Butternut canker,

Pages 73-82 in Walnut Insects and

Diseases. Workshop Proceedings, Jun

13-14, 1978, Carbondale, IL. U.S. Dept.

Agric. For. Serv., Gen. Tech., Rep.

NC-5 2. 100 p.

N_cholls, T. H., K. J. Kessler, Jr., and J.

E. Kuntz. 1979. How to identify

butternut canker. U.S. Dept. Agric.

For. Serv. Leaflet, N. Cent. For. Exp.

Stn., St. Paul, MN. 5 p.

Orchard, L P. 1981. Butternut canker:

screening seedlings for disease

reistance. (Abstr.) Phytopathology

71:247.

• Peterson, H. D. 1977. Wisconsin forest

products price review, December, 1977.

Lumber Edition. Univ. Wisconsin Ext.

Pub I, 4 p.

Renlund, D. W., ed. 1971. Forest pest

conditions in Wisconsin. Wis. Dept.

Nat. Res. Ann. Rep. 53 p.

Schroeder, J G, 1972. Butternut : an

American wood. U.S. Dept. Agric. For.

:Serv. Leaflet 223. 6 p.

Spencer, J. S. Jr., and H. J. Thorne.

1972. Wisconsin's 1968 timber resource

--a perspective. N. Cent. For. Exp. 

Stn. Bull., St. Paul, MN. (U.S.D.A.

.

.26 

, 
REACTIONS OF JUGLANS SPECIES TO BUTTERNUT CANKER AND IMPLICATIONS

FOR DISEASE RESISTANCE I

L. P. Orchard, J. E. Kuntz, and K. J. Kessler, Jr. 2

Butternut canker, caused by the fungus Sirococcus

clavigi_nenti-juglandacearum Nair et al, is the most

important disease of butternut (Juglans cinerea L.).

Infected butternuts often have many cankers and severely

cankered tree_ die. Several economically important species

belong to the genus Ju_lans. In order to determine their

relative resistance or susceptibility, :saplings of several

Ju_lans species and hybrids were wound-inoculated under field

conditions at the U.S.F.S. Tree Improvement Center,

Carbondale, Illinois. Cankers developed on all inoculated

species and hybrids including trees of J.-- nigra, J. re_ia, J. 

sieboldiana, J. regia x nigra, and J. sieboldiana x cinerea.

Nine months after inoculation the largest cankers had

developed on J. regia which appeared to be highly susceptible

• to the canker fungus pathogen.

INTRODUCTION ages, which can occur at all heights 

twigs, branches, and stems. In the sp

Butternut canker, caused by the fungus a thin black fluid exudes from cracks 

Sirococcus clavigignenti-_andacearum Nair bark; it stains the bark brown. This 

et al. (1979), is the most important disease often the easiest way to detect young

of butternut (Ju_lans cinerea L.). The cankers. The wood beneath the exudate 

disease was noticed first in Wisconsin in stained dark brown to black in a verti

1967 (Renlund, 1971). In 1978, Anderson and oriented, elliptical pattern. Young 

LaMadeleine (1978) reported its occurrence on branches appear as dark, irregularly

throughout the range of J. cinerea in the elongate, sunken areas frequently asso

eastern United States. with a leaf scar, lenticel, or various

wounds. Older cankers are perennial,

On butternut, the fungus incites fusiform, vertically oriented, and may 

perennial cankers, of various sizes and wholly or partially covered with shred

bark. The fungus produces a thin stro

the bark from which hyphal pegs and

Ipaper presented at the 1981 Joint spore-bearing pycnidia form under the

Meeting of Walnut Council/Northern Nut loosening outer bark (Kuntz et al., 1

Growers Association. Purdue University, Infected trees usually bear numerous 

West Lafayette, Indiana, Aug. 9-14, 19.81 and often die as a result.

2Graduate Research Assistant and

Professor respectively, Departments of Plant In some stands all the infected

Pathology and Forestry, University of butternut trees have died, but in othe

• Wisconsin, Madison, WI, 53706, and Kessler, stands one or several apparently healt

K. J., Jr. Principal Plant Pathologist, trees remain. These canker-free trees 

Forest Science Laboratory, Carbondale, found in infection pockets where inocu

Illinois, 62901. abundant, which suggests that they may 

resistant to the pathogen.
In addition to butternut, several inoculation. For controls, a piece of

economically important species belong to the sterile agar alone was inserted into each of

genus Ju_lans. These include black walnut the two control wounds. The wounds were

(J nigra L.), Persian walnut (J. regia L.), wrapped with wet cotton and covered loosely

and Japanese walnut (J. ailantifolia Cart.) with aluminum foil.

(Smith, 1953).

In the spring of 1980, the inoculations

In Order to determine their relative were observed for canker development, and on

resistance or susceptibility to butternut July 31, 1980, all the inoculations were

canker, trees of these species and some of examined, cankers were measured, and

their hybrids were wound-inoculated with S. symptoms were described.

clavigignenti-_uglandacearum under field

conditions at the U.S.D.A.U.S. Forest

Service Tree Improvement Center, Carbondale, RESULTS

lllinois.

. Cankers began to appear and the fungus

pathogen was reisolated in the early

MATERIALS AND METHODS spring. Both confirm our observation of

' similar fall infections and rapid canker

In October, 1979, certain JuElans development in the spring on trunk sprouts.

Species and hybrids, 10-20 years old, (Table By July 31, 1980, cankers had developed on

I) were branch-inoculated with mycelium and all species and hybrids which had been

spores of S. clavigignenti-juglandacearum, inoculated in October 1979 (Table I). The

Inoculated branches were generally 1-3 cm in cankers were distinctive for each species of

diameter, Juglans. No cankers developed at any of the 

noninoculated control wounds. J. 

Six tangential slanting knife wounds, ailantifolia is now the accepted name for

approximately 1-2 cm long, were made through Japanese walnut and is synonymous with J.

• the bark and into the sapwood on each tree sieboldiana and J. sieboldiana vat.

tested. Four wounds were used for _ cordiformis (Br£nkman, 1974; McDaniel,

inoculations, and two served as 1979). In order to preserve information,

n0ninoculated controls. Usually, the however, the taxonomic designations below

inoculated wounds Were made on one branch follow those used at the Tree Improvement

and the control wounds were made on another Center.

branch, but sometimes the control wounds

were made distal to the inoculated wounds on Characteristic symptoms and signs of

She same branch. Immediately after" butternut canker for each species were as

wounding, a piece of mycelial colony of the follows:

pathogen growing on agar was inserted into 

each of the four wounds used for 

Table I. Canker development following branch inoculations of Juglans

species and hybrids.

• Species Trees Cankers Mean canker 

• Inoculated measured I length (cm)

J. nigra 15 46 16.5

J..=. regia 15 51 19.5

J. _ x nigra 15 58 18.0

J. sieboldiana 8 28 14.0

I J. sieboldiana vat. | -=-

I cord iformis 9 34 10.5

I J. sieboldiana x

cinerea 3 8 14.0

i _' J. cordiformis x

cinerea 5 18 15.5

J. cinerea

x cord iformis 6 12 19.0

I Cankers were not measured on branches that had been killed.

28
.

J. nigra J. sieboldiana x cinerea and

J. cordiformis x cinerea

Cankers were usually externally

indistinct, but were detected as a Cankers were distinct, sunken, and

discoloration of the inner bark. Cankers slightly discolored. Small branches (2 

were elliptical; chocolate brown exudate were killed and dead branches bore hypha

and/or a dry black "soot" appeared on some pegs. Cankers resembled those formed o

canker faces; branches 1 cm in diameter or sieboldiana.

smaller were killed; and hyphal pegs were

produced beneath loosening bark on these

dead branches. J. cinerea x cordiformis m

Cankers resembled those formed on mJ

J_ regia cinerea. Cankers were smooth, slightly

sunken, light blue to gray often with a

Cankers were slightly sunken tO flat,but sooty patch, with abundant hyphal pegs, 

o with distinct margins, often appearing little callus production along the canke

blue-gray in color, elliptical in shape, and margin.

extending for roughly equal distances up and

down the branch from the inoculation point.

The bark often was cracked in the tissue DISCUSSION

alongside the canker. A chocolate brown

exudate and/or a patch of sootiness appeared The collection of Juglans species a

on some canker faces. Branches 1 cm in Tree Improvement Center at Carbondale,

diameter died, and characteristic hyphal Illinois provided trees to inoculate un

pegs developed under loosening bark on these field conditions within the known range 

dead branches. Branches 3 cm in diameter the pathogen. The potential threat of 

were approximately 3/4 girdled, c!avigignenti-juglandacearu m to Ju_lans

• species is great. With the exception o

tree (J. sieboldiana var. cordiformis),

J. regia x nigra cankers developed at every wound inocul

on every tree, or the branch was killed 

Cankers resembled those on J. regia, girdling before a discrete canker forme

Cankers were sunken, distinct, blue-gray in We realize that our technique, i.e. dir

color, with longitudinal bark cracking both inoculation of a wound with mycelium an

adjacent to and within the canker. Hyphal spores of the pathogen, may mask some

._. pegs were present occasi_nally on living mechanisms of disease resistance. Such

branches, factors as low sporulation, inability 

inoculum to spread, adverse environment, 

barriers to penetration could dramatical

J. sieboldiana and J. sieboldiana affect the course of the disease in the

- . var. cordiformis field. Nevertheless, given the high va

of the trees, a severe technique establ

Cankers varied from indistinct, slightly their resistance or susceptibility to

sunken cankers to distinct, discrete, sunken cankering once infected. Factors which 

to flat cankers. The branches often were influence disease incidence and severit

swollen in the canker region with bark these species must be the subject of fu

cracking alongside the canker. Occasionally investigations.

there was a trace of sootiness on the canker

face. On one tree of J. sieboldiana var.

, cordiformis, the inoculated wounds THE IMPORTANCE OF S. CLAVIGIGNENTIcompletely sealed and were indistinguishable JUGLANDACEARUM TO THE MAJOR

from the check wounds except that the inner JUGLANS SPECIES

bark of the inoculated wounds was discolored

• (as with all inoculations), whereas the Black Walnut

inner bark of the noninoculated checks was

not discolored Branches up to 2 cm in Kuntz et al. (1979) reported that b

diameter were killed, and hyphal pegs formed walnut is infected only infrequently in

on the dead branches, natural woodlands, but that artificial

inoculations in experimental nurseries

produce progressive, killing stem canke

black walnut seedlings and branch canke

saplings. Following our inoculations,

• 
°

cankers developed on black walnut; also Butternut

inoculated branches of black walnut were

killed more often than were those of other Butternut is highly susceptible to S.

species tested. Current studies seek to clavi_ignenti-juglandacearum in all stages

determine whether infected black walnut of growth; it may become an endangered

branches die more often and more quickly species (Anderson and LaMadeleine, 1978). 

than do infected branches of other Ju_lans Canker-free butternuts do occur in infection 

Species. If infected walnut branches do die pockets and may be resistant. Orchard et

rapidly, a hypersensitive reaction may al. (1981) and Orchard (1981) reported a

exist. Such quick killing of infected host possible form of resistance in young

tissue might restrict further development of butternut seedlings in which cankers do not

the pathogen and account for the low develop in certain infected

frequency of cankered walnuts in natural seedlings.Reasons for survival of

forest stands. Meanwhile, new plantings of asymptomatic seedlings, though infected, are

black walnuts should not be made under or sought. Whether this reaction can be a

near cankered butternuts, significant source of resistance in breeding

programs is not yet known. Butternut is an

Persian Walnut attractive and useful nut tree that is hardy 

' in the northern United States and southern

==J.. regia appears to be highly suscep- Canada, but butternut canker must be

tible to S._.clavigignenti-juglandacearum. At controlled if this species is to be

the Tree Improvement Center the longest exploited. The role of environmental

cankers developed on this species. Because conditions, especially stress factors that

of this, butternut canker may become a may favor or inhibit infection and disease

serious disease through much of the world development, and possible resistance of

where this commercially important species is selected species and hybrids also must be

grown, clarified.

Further study will continue examination

of these and other inoculations. Meanwhile SUMMARY

detection surveys of midwestern plantings " 

are needed to assess the disease potential J. nigra, J. regia, J. ailantifolia, J.

of butternut canker on J. regia, cinerea, and several of their hybrids are

susceptible to .=S.. clavigignentiHopefully the disease may not prove juglandacearum. The fact that J. regia

serious in some regions, e.g. California, proved highly susceptible to canker 

for climatic reasons. Nevertheless," .development following direct inoculation

infected material must not be transported to warns that butternut canker may well have

regions where the disease has not been international significance. Further testing

reported. Infected butternuts in the must determine the long-term course of the

vicinity of Persian walnut plantations in disease on these species, especially _J"

the eastern United States should be removed regia, the nature of the "hypersensitive"

and destroyed. Named varieties of Persian reaction in J.=.. nigra, the possibililty for

walnut must be tested for disease reaction resistance in J. ailantifolia and J.

and possible resistance, cinerea, and th-e environment and s_te

. • factors that influence disease spread,

, Japanese Walnut especially for regions where the susceptible

Ju_lans species are economically important.

Japanese walnut is not as important a

species as Persian walnut or black walnut, 

The species appears to be susceptible to the LITERATURE CITED

canker fungus. Nevertheless, the cankers

that developed on this species were Anderson, J. L., and LaMadeline, L. A.

generally smaller, and on one tree the wound 1978. The distribution of butternut

sealed and canker development was decline in the eastern United States.

restricted. Possibly this species may U.S. Dept. Agric. For. Serv.,

provide a type of resistance in breeding Northeast. Area State and Private

programs, _not only for improved Japanese Forestry Survey Rep. S-3-78. 4p.

walnut but also for butternuts, black

walnuts, and Persian walnuts. Brinkman, K. A. 1974. Juglans L. Walnut.

Pages 454-459. =in=.-. Seeds of Woody Plants

of the United States U.S. Dept. Agric.,

For. Serv. Handbook 450. 883 p.
o

Kuntz, J. E., Prey, A. J., Jutte, S., and

Nair, V. M. G.. 1979. The etiology,

distribution, epidemiology, histology,

and impact of butternut canker in

Wisconsin. Pages 69-72 in Walnut

Insects and Diseases. U. S. Dept. of

• Agric. For. Serv. Gen. Tech. Rep. NC-52.

McDaniel, J. C. 1979. Other walnuts,

including butternut, heartnut, and

_i hybrids. Pages 98-110 i_n.nR. A. Jaynes,

ed. Nut Tree Culture in North America.

Northern Nut Growers Association, Inc.,

Hamden, Conn.

Hair, V.M.G., Kostichka, C. J., an.d Kuntz,

J- E. 1979. Sirococcus clavigignentijuglandacearum: an undescribed species

causing canker on butternut. Mycologia

71: 641-646.

Orchard, L. P., Guries, R. P., and Kuntz, J.

E. 1981. Butternut canker: Screening

seedlings for disease resistance.

(Abstr.) Phytopathology 71:247.

Orchard, L. P. 1981. Butternut canker:

screening seedlings for disease

• resistance. Progress report.

• Departments of Forestry and Plant

Pathology, University of Wisconsin,

Madison.

Renlund, D. W. 1971. Forest pest conditions

in Wisconsin. Wis. Dept. Nat. Res. Ann.

Rep. 1971. 53p.

Smith, J. R. 1953. Tree crops, a permanent

agriculture. Devin-Adair, New York.

408 p.

°

,

• 
°

DIEBACK, DECLINE, AND STEM CANKER OF BLACK WALNUT

IN WISCONS IN1

J. E. Kuntz and A. J. Prey 2

Abstract.--The survival, growth, and productivity of

walnuts are limited by several deleterious agents including

l diseases, insects pests, and weeds. Although many walnut

[ , diseases cause little economic loss, several can be

[ destructive under conditions favoring infection and disease

I

development. Recently in Wisconsin (SW), Iowa (NE), and i

• Minnesota (SE), a vertical, elongate, and sometimes girdling

stem canker has severely damaged and even killed young

walnuts in plantations. Two species of Fusarium have been _

isolated consistently from representative cankers. One

Fusarium sp. has induced cankers on stem-inoculated walnut

seedlings in greenhouse studies. Meanwhile, this stem canker

-I has been complicated by branch cankers associated with a

Phomopsis species and twig dieback associated with a

Phyllosticta species. Current research seeks to clarify the

significance and relative roles of these fungus pathogens.

INTRODUCTION nurseries have greatly expanded their

seedling production (Brinkman, 1974).

Black walnut (Juglans nigra L.) is an

extremely valuable hardwood in eastern and Unfortunately, the survival, growth, and

central United States, prized for .the flavor productivity of walnuts are limited by

of its nuts (Zarger, 1969), for the beauty several deleterious agents and including

of its wood (Blyth, 1973; Clark, 1969), and diseases, insect pests, and weeds (Berry,

for its aesthetic appearance as a shade tree 1973; Bey and Williams, 1976; Johnson, 1969;

(MacDaniels, 1979). In recent years, its Miller, 1973; USDA, 1979; Weber, Anderson,

culture and management have been studied and Hoffard, 1980). Numerous plant

extensively (Clark, 1973), facilitating the pathogens, mainly fungal, attack walnuts of

establishment of numerous plantations in all ages and incite different types of

Central States (Burke and Williams, 1969; disease (USDA, 1960). Although most walnut 

' Schlesinger and Funk, 1977). To meet the diseases cause little economic loss, several

increasing demand for planting stock, forest can be destructive under conditions favoring

. infection and disease development.

1Paper presented at the 1981 Joint

Meeting of Walnut Council/Northern Nut STEM DISEASES

' Growers Association. Purdue University,

West Lafayette, Indiana, Aug. 9-14, 1981. Stem diseases of walnut are of special

2professor, Departments of Plant concern since they lower the quality and

Pathology and Forestry, University of quantity of lumber and veneer logs, reduce

Wisconsin, Madison, Wisconsin, 53706, and nut yields, and may even kill infected 

Forest Pathologist, Forest Pest Control trees. According to Hepting (1971), 

Section, Bureau of Forestry, Wisconsin perennial target canker, caused by the

Department of Natural Resources, Madison, fungus Nectria galligena Bres., seriously

Wisconsin, 53711. damages walnuts in the southern Appalachian 

region. In Wisconsin, this canker has been

of little consequence.
In contrast, recently in Wisconsin, detected infrequently on black walnuts

Iowa, and Minnesota, a vertical, elongate, growing in mixed stands with severely

and sometimes girdling stem canker has infected butternuts (Kuntz et al, 1979).

severely damaged and even killed young Nevertheless, artificial inoculations o

walnuts in plantations. (Kuntz, Orchard, young walnut seedlings, older saplings, 

and Tisserat, 1980). The sunken, elongate branches of mature walnuts have incited

cankers are of various sizes from small bark typical elliptical to fusiform, dark, s

cracks to long, vertical strips, sometimes cankers or a rapid dying of inoculated

extending from the root collar into the branches. Girdling stem cankers frequen

crown. Both bark and wood are affected. In killed inoculated walnut seedlings. Tr

old cankers, bark loosens and sloughs off. inoculations of walnut saplings incited

Infected bark is dark brown with distinct slowly progressing perennial cankers fr

margins adjacent to healthy tissue, which the fungus has been isolated

Underlying wood is brown to black. Trunk or repeatedly (presently up to 6 years).

basal sprouts frequently develop below

girdling cankers. . Meanwhile, these stem and branch

cankers, together with the crown dieback 

Two species of Fusarium have been tree decline, have been complicated by

isolated repeatedly from representative small, dark, sunken branch cankers

cankers. Pathogenicity of one Fusarium associated with a Phomopsis species and 

isolate has been demonstrated by rapid wilt and dieback of succulent sho

wound-inoculation of walnut seedlings in associated with a Phyllosticta species

greenhouse studies. Young walnut seedlings (U.S.D.A., 1960). Moreover, Melanconium

that became infected developed dark, sunken, oblon_um Beck frequently invaded dead a

elongate, stem lesions. In cases where dying branches where it fruited abundant

stems were girdled, the inoculated seedlings

died. Detection and appraisal surveys wil

continue to monitor canker-diebacks of

In two Minnesota plantings, more than walnuts and butternuts. Meanwhile, cur

50% of the trees are cankered. (DIN DNR, research seeks to clarify the role, imp

1980). Most cankers range in age from 2 to and activities of pathogens associated 

" 6 years old. Cankers may encompass either these diseases.

lateral branch pruning scars or dead branch

stubs. Fortunately, in the field, most The authors express appreciation to 

perennial stem cankers have progressed Hayes, Forest Insect and Disease Special

slowly and some cankers are closing by the MN-DNR, Rochester, MN., 55901, for loca

formation of marginal c_llus, diseased walnut stands and plantations 

Minnesota and for collecting diseased

A Fusarium canker of walnuts has been specimens.

reported in North Carolina, Indiana,

Tennessee, and Missouri (Minnesota DNR,

.. 1980). Whether this stem canker is the same LITERATURE CITED

as that reported by Kessler (1974) to occur

on walnut plantations in Illinois, Indiana, Berry, F. H. 1973. Diseases. Pages 8

Missouri, and Iowa remains to be clarified, in Black Walnut as a Crop. Black Wal

Kessler found an apparent symbiosis between Symposium, Carbondale, IL., Aug. 14-

Fusaria and ambrosia beetles, Xylosandrus 1973. U.S. Dept. Agric. For. Serv. 

germanus, which provided wounds and Tech. Rep. NC-14. l14p.

infection courts. Berry (1973) also

reported a basal canker disease in Bey, C. F., and R. D. Williams. 1976. 

. plantation walnuts where bark and cambium control in black walnut plantations. 

tissues were killed at the ground line. The S. Dept. Agric. For. Serv. Res. Note

resulting canker girdles the stem and the NC-203. 4p.

crown dies. The cause is unknown.

• Recently, several species of Fusarium are Blyth, J. E. 1973. Timber demand and 

reported to cause cankers on black walnut in Pages 7-9 in Black Walnut as a Crop.

the Midwest (Weber, Anderson, and Hoffard, Black Walnut Symposium, Carbondale, 

1980). Aug. 14-15, 1973. U. S. Dept. Agric

For. Serv. Gen. Tech. Rep. NC-14. 

A major canker of butternut, incited by

the fungus pathogen, Sirococcus

clavigignent i-j u_landacearum (Nair,

Kostichka, and Kuntz, 1979), has been

• 
o

Brinkman, K. J. 1974. I_Ju L. Walnut. Miller, W. E. 1973. Insects as related to

Pages 454-439 in Seeds of Woody Plants in wood and nut production. Pages 91-96 in

.the United States. U. S. Dept. Agr. Black Walnut as a Crop. Black Walnut

Forest Serv. Agric. Handbook 430. 833p. Symposium, Carbondale, IL.., Aug. 14-13,

1973 U.S. Dept. Agric. For. Serv.

Burke, R. D., and R D. Williams. 1973. Tech. Rep. NC-4. l14p

Establishment and early culture of

plantations. Pages 36-41 i__nR. A. Jaynes Minnesota Department of Natural Resources.

.(ed). Handbook of North American Nut 1980. 1980 Forest insect and disease

Trees. Northern Nut Growers Assoc., report. MN-DNR. DiD. For. Rep. 72p.

Knoxville. 421p.

Nair, V.M.G., C. J. Kostichka, and J. E.

Clark, F P. 1969. Growing black walnut Kuntz. 1979. Sirococcus

timber. Pages 212-213 i_=nR. A. Jaynes clavigignenti-juglandacearum: an

(ed). Handbook of North American Nut undescribed species causing canker on

Trees. Northern Nut Growers Assoc., butternut. Mycologia LXXI: 641-646.

Knoxvi 11e. 42Ip.

" Schlesinger, R. C., and D. T. Funk. 1977.

Clark, F. P. 1973. Culture: past, present, Manager's handbook for black walnut.

and future. Pages 30-32 i._n Black Walnut U.S. Dept. Agric. For. Serv. Gen. Tech.

as a Crop. Black Walnut Symposium, Rep. NC-38. 22p.

Carbondale, IL., Aug. 14-15, 1973. U.S.

Dept. Agric. For. Serv. Cert. Tech. Rep. U.S. Department of Agriculture. 1960.

NC-14. 114p. Index of Plant Diseases in the United

States. U. S. Dept. Agric. Handbook

Hepting, G. H. 1971. Diseases of Forest 165. 331p.

and Shade Trees of the United States.

U. S. Dept. Agric. For. Serv. Agric. U.S. Department of Agriculture, Forest

Handbook 386. 638p. Service. 1979. Walnut Insects and

Diseases. Workshop Proc. U. S. Dept.

Johnson, W. T. 1969. Plant pests. Pages Agric. For. Serv. Gen. Tech. Rep. NC-52.

67-136 in R. A. Jaynes (ed). Handbook of 100p.

North American Nut Trees. Northern Nut

Growers Assoc., Knoxville 421p. Weber, B. C. R. L. Anderson, and W. H.

Hoffard. 1980. How to diagnose black

Kessler, K. J., Jr. 1974. An apparent walnut damage. U. S. Dept. Agric. For.

symbiosis between Fusarium fungi, and . Serv. Gen. Tech. Rep. NC-37. 21p.

ambrosia beetles causes canker on black

walnut stems. Plant Dis. Reptr. Zarger, T. G. 1969. Black walnuts -- as

38:1044-1047. nut trees. Pages 203-211 in R. A. Jaynes

(ed). Handbook of North American Nut

Kuntz, J. E., L. P. Orchard, and N.A. Trees. Northern Nut Growers Assoc.,

TisSerat. 1980. Important diseases on Knoxville. 421p.

walnuts in Wisconsin. Proc. 1980 Ann. 

Mtg. Wis.-Mich. Section, Society of Amer.

Foresters, Sept. 18-19,. Marquette, 

Michigan.

Kuntz, J. E., A. J. Prey, S. Jutte, and 

•V.M.G. Nair. 1979. The etiology,

distribution, epidemiology, histology, 

and impact of butternut canker in

Wisconsin. Pages 69-72 i_.nnWalnut Insects

and Diseases. Workshop Proc. U. S. Dept.

Agric. For. Serv. Gen. Tech. Rep.

NC-52. lO0p.

MacDaniels, L. H. 1979. Nut trees -- a

valuable resource. Pages 1-8 in R. A.

Jaynes (ed). Nut Tree Culture in North

America. Northern Nut Growers Assoc.,

Knoxvi 1ie. 446p.

34
DEVELOPMENTS IN DISEASE CONTROL OF WALNUT ANTHRACNOSE

Steven Cline I

Abstract.--Walnut anthracnose, caused by Gnomonia leptosty!a, is the most serious foliar disease of black walnut.

Fungicide treatments, nitrogen fertilization, and mechanisms

° of disease resistance have and are currently being examined

for use in anthracnose control. Benomyl sprays can reduce

anthracnose severity but are restricted for use only on nonnutbearlng trees. Chemical analysis of nut meat tissue detected benomyl but at levels below the federal tolerane level

required for registration. Bioassays of benomyl residues on

leaves and nut hulls showed that only two timed applications

per year are necessary, provided normal rainfall conditions

exist. Disease severity may be reduced by nitrogen fertilization. Trees treated with N alone had less anthracnose than

those receiving other combinations of macronutrients. Resistance to anthracnose has been observed in juvenile leaves and

• is currently being investigated.

__ L , J •

The fungal disease, walnut anthracnose, is reduce disease incidence. The removal of 

caused by Gnomonla leptostyla (imperfect stage, fected leaf material (overwlntering site) 

Marssonlna juglandis) and has become the primary suggested to reduce the inoculum potential

important leaf pathogen of the host in the cent- forest conditions this practice is not pra

• ral and eastern United Sta_es. Berry, in the but certainly pruning could be employed by 

1960's, suggested that this disease reduced tree homeowner for shade trees. At the present 

growth through premature defoliation and that it anthracnose control in walnut plantations 

affected nut quality and quantity. Exactly how chieved with the use of protectant fungici

damaging this disease is to growth and nut prod- Alternatives to fungicide applications are 

uction is yet to be quantitatively determined, rently being investigated. Nitrogen ferti

tion seems to reduce disease severity. Wh

Studies concerning mycology (Matteoni and disease-resistant cultlvars are not curren

Neely), pathogenesis, and epidemlology (Black available to growers, studies are being c

and Neely) were done in the 1970's. The infor- to understand the nature of resistance obs

marion that was generated has paved the way to in juvenile leaves and the applicability 

better understand the host-pathogen relation- breeding for resistance.

ships and the avenues for disease control strategY,

, FUNGICIDES

. Disease control at the present time is

limited to preventive cultural practices and Of six commercial fungicides applied 

the use of protectant fungicides applied to the foliar sprays, by researchers at the Illin

foliage. Epidemlological studies indicate that Natural History Survey, benomyl (Benlate 

tree moisture is essential for infection. Prun- DuPont) at the rate of 1 ib/100 gal was t

ing trees to increase the sun's penetration and effective for anthracnose control. Sprays 

air circulation will hasten evaporation and applied twice, one on June 2 and then on 

This fungicide was statistically superior 

sin M 70 W, Manzate 200 80 W, Polyram 80 

iSteven Cline is a graduate research as- 6 F, and Trlflorine 6.5 EC, giving 97% co

over defoliation.

sistant at the Illinois Natural History Survey,

Illlnols Institute of Natural Resources, Champaign, illinois 61820.

-
I

o

The timing 7of fungicide applications is Carbondale, Illinois were soil-injected or folimportant to good control. Epidemiological Jar-sprayed with benomyl or trunk-infused with

studies in Illinois showed that infection from Lignasan BLP. Nuts collected in August and Septascospores occurred in late May while conidial ember were analyzed for the breakdown product

infections were produced in early July. To MBC (carbendazim) by gas chromatography. Results

determine how the timing of benomyl sprays is indicate that very low levels of MBC were present

important to control, a study was conducted to in several samples tested, however, in all setupexamine the persistence of this compound on lea examined, the quantities detected were well

black walnut leaves and nut hulls in 1978 and below the federal tolerance level of 0.13 ppm.

1979. Four testing sites were chosen in Illi- We, therefore, have recommended the registration

nois. FOliar sprays were applied at the rates of benomyl for use on nut-bearing trees.

of 1 Ib (IX), 2 ibs (2X), and 4 ibs (4X)/lO0

gel between late May and early .July to established trees. Fungicide bioassays were conducted FERTILIZATION

on Samples of leaf and nut hulls collected at

variousperiods following treatment. A benomyl- preliminary field testing of nitrogen fers_ensitive fungus was used to detect persisting tilizers on anthracnose severity (Neely, 1981) 

residues on these plant parts. Rainfall was from 1973-1977 showed that a reduction in dis- 

monitored over the testing periods. _ eased leaflets from 46 to 61% occurred as evaluated in August and September, respectively. This

Our resultsdetermined benomyl to be fair- was studied more intensely in 1978 and 1979 in 

ly persistent as the compound inhibited germ order to verify these trends. Tests were destube development for approximately 6 weeks on igned to establish the effect of nutrient source,

the foliar surface, provided that precipitation rate and timing of fertilizer application. Nitrodid not exceed i0 cm/week. Higher rates of ap- gen (N) alone and other combinations of nitrogen, 

plication (2X, 4X) did not persist significantly phosphorus (P), and potassium (K)were compared

longer than the IX rate, implying that these at a uniform soil surface application rate of 

higher rates w°uld n°t increase anthracn°se c°n- 29 g N/m2 (iX) (6 ibs/1000 sq ft) applied in 

trol. When benomyl persistence was studied under April, June or October. Additional applications

conditions following simulated rainfall applica- of ammonium nitrate were made at I/2X and 2X

tions, benomyl residues were inhibitory to germ rates. A foliar treatment of urea was also testtube development of the test fungus in excess ed spraying trees to run-off with three applicaOf 24 cm of rainfall. Our conclusions suggest tions in mid-May, early June, and late June at

that other factors besides rainfall cause its the i0 g/l rate.

removal or degradation under field conditions.

Black walnut is observed to be more resist-

• On nut hulls, benomyl was persistent for ant to anthracnose and there is a delay in pre5-7 weeks at the iX rate while 2X and 4X rates mature defoliation when nitrogen fertilizers are

remained effective in excess of 7 weeks. The applied. The rates of application are correlated

effect of rainfall on nut hull persistence could directly with foliage color and growth, and innot be determined, versely correlated with disease severity (table

i). Disease control increased by 20, 31, and

Based on our studies in Illinois, we recom- 52% with I/2X, IX, and 2X nitrogen treatments as

mend spray applications of benomyl fungicide to compared to the untreated controls. Soil-applled

begin in mid-to !ate-May when ascospores are ammonium sulfate, ammonium nitrate, and urea were

released. A rate of 1 15/100 gel was demonstra- equally good nitrogen sources. Early spring as

ted to be effective for control of walnut an- well as mid-summer applications are both effecthracnose. With moderate (normal) rainfall, a tive. The combination of potassium and/or phossecond spray is not generally required until phorus with nitrogen reduced the effectiveness

• early July when conldla are released. When of nitrogen applied alone. Foliar treatments

rainfall does exceed i0 cm/week, an earlier with urea were not significantly more effective

second application may be necessary than no treatment.

! The systemic action of benomyl and the un- At present, we recommend fertilizing trees

Certainty of movement into floral parts and with N-containing compounds (ammonium sulfate,

developlngnut meats limits its registration for ammonium nitrate or urea) applied at the rate of

use on non-nutbearing trees. To establish the 250 ibs/acre to reduce disease severity and stimupotential for registration, we conducted a study late tree growth. Fertilizers may be applied any

to determine the level of residue accumulation time during the year, however, best response can

Of ben0myl in nut meats following its applica- be expected when applications are made prior to

tion for disease control. In 1979, trees at bud break in the spring.

36
Table l.---Effects of nutrients applied to black and nut production. Successive years of p

walnut trees in 1978 and 1979. ture defoliation can weaken trees and reduc

energy reserves from efforts to refollate. 

ed trees are more subject to damage due to 

sects, root-rotting and other pathogens. W

Diameter

Rate Disease Color growth we recommend sound cultural practices (good 

selection, scheduled pruning and a balanced 

Treatment (g/m2). severit_ / ratin_ / (ram)' tillzation program) to reduce favorable co

None 44.0 3.1 4.3 tlons for anthracnose development, fungicid

Urea Ii sometimes the only alternative. From our 

(foliar) _-' 44.7 3.3 4.8 benomyl is the most effective chemical mean

PK 29 41.5 3.3 4.5 control when applied to the foliage at the 

NpK 29 . 36.8 3.6 6.1 of i ib/100 gal. Current IPM strategies r

NH4NO 3 14.5 35.2 3.5 5.0 that we move from pesticides to other means 

NK 29 34.3 3.9 6.7 disease control. Additional research effor

IqH4NO3 29 34.2 3.7 6.5 into alternatives are needed before they b

NP 29 33.7 3.8 5.4 valid, environmentally and economically so

NH4NO 3 29 31.1 3.9 6.0

(NH4) 2SO 4 29 30.8 _. 7 5.8

Urea 29 28.8 3.7 6.3 LITERATURE CITED

NH4NO 3 58 21.3 4.1 7.7

Berry, F. H. 1961. Etiology and control 

l--/Three foliar applications sprayed to runoff at walnut anthracnose. Ph.D. Thesis, Univer

2/10 g/l. of Maryland, College Park, Maryland. 64 

Percentage leaflets with one or more lesions. Black, W. M. 1977. Ecology and epidemiolo

--_'l=yellow green; 3=average green; 5=dark green, walnut anthracnose. Ph.D. Thesis, Unive

of Illlnois, Urbana, Illlnols. 83 pp.

Black, W. M. and D. Neely. 1978. Effects 

' RESISTANCE temperature, free moisture, and relative 

dity on the occurrence of walnut anthrac

Currently, cultivars resistant to walnut an- Phytopathology 68: 1054-1056.

thracnose are not available to foresters. Early Matteonl, J. A. 1977. Gnomonia leptostyla 

attempts by Berry (1964) to rate infected field- its pathogenesls in black walnut. Ph.D

grown trees across 40 cultivars failed to show Thesis, University of Illinois, Urbana,

conclusive evidence for disease resistance. When Illinois. 80 pp.

optimum conditions for infection were present, Matteonl, J. A. and D. Neely. 1979. Gnomo

trees that were previously thought to be less leptostyla: growth, sporulation, and he

susceptible became as severely infected as other thallism. Mycologia 71: 1034-1042.

cultivars. Attempts by Black (1977) to select Neely, D. 1981. Application of nitrogen 

for resistance among species of Juglans showed llzer to control anthracnose of black w

that a large variation in resistance exists. In Plant Disease 65: 580-581.

field studies by Neely (1981) correlations between height, diameter, and anthracnose ratings

were not significant, however, faster growing

trees tended to be more resistant.

Observations of artificially infected and

naturally infected leaves suggest that juvenile

leaves are more resistant to infection than olde_

more mature leaves. Pathogenesis testing by

Matteoni (1977) determined that leaves of all

ages exhibited some lesions but lesions on younger leaves are smaller and either have fewer or

no acervuli. Research efforts investigating

the effects of nitrogen fertilization, leaf age

andgr0wth as related to anthracnose susceptibility, are currently underway to determine the

potential applicability of this type of resistance for controlling anthracnose.

Walnut anthracnose is not well known in

terms of the economic l'oss in annual growth

• 
WALNUT ROOT ROT IN SEEDBEDS, HEELING-IN BEDS, AND STORAGE1

..

N. A. Tisserat, J. E. Kuntz, R. P. Guries, and R. F. Camp 2

Root rot can be a limiting factor in the production of

one-year-old (1-0) black walnut seedlings at the Wilson State

Nursery, Boscobel, Wisconsin. So far, root rot in seedbeds,

though present, has not caused serious damage; however,

fall-lifted seedlings held over winter in heeling-in beds are

subject to heavy losses resulting from root rot. Soil-borne

fungi commonly associated with walnut root rot in Wisconsin

included Phytophthora cltrlcola, Cylindrocladium sp., and

Fusarium spp. In most years, root rot of stored seedlings was

avoided by spring lifting. Fall-lifted seedlings stored at 4

C in heavy paper bags had a much lower incidence of root rot

and higher field survival rates than did fall-lifted,

heeled-in seedlings. Survival rates of trees stored over

winter in bags were similar to survival rates of trees that

were spring-lifted.

INTRODUCTION heaving (Schlesinger and Funk, 1977). 

In recent years, the demand for quality In Wisconsin until 1978, seedlings were 

black walnut (Juglans nig_a L.)has machine-lifted in November, hand-graded;

increased walnut plantings throughout bundled, and placed in "heel-in" beds for 

southern Wisconsin and adjacent areas of overwinter storage in preparation for spring 

central United States. Intensive management shipment. Frequently, in the heel-in beds, 

is practiced to provide optimal growth and many of the injured roots deteriorated or 

quality of the trees (Schlesinger and Funk, • rotted, resulting in extensive spring

1977). To insure proper density and culling (Tisserat et al., 1980). Although 

uniformity, new plantations are established the exact cause of root rot in Wisconsin is

with one-year-old nursery transplants rather not known, soil-borne root-rotting fungi

than'by direct seeding. In Wisconsin alone, have been associated with some of the

the state forest nurseries distribute decayed roots. Studies in other areas of 

annual!y over 300,000 black walnut seed- the country indicate that both environmental

lings. Spring planting of young seedlings (Young, 1943) and biotic agents (Green and 

is recommended since fall-planted stock is Ploetz, 1979) may be involved. Species of 

subject to winter injury and frost Cylindrocladium and Phytophthora have

incited root rot of black walnut seedlings

growing in nursery beds (Cordell and

Ipaper presented at the 1981 Joint Matuszewski, 1974; Green and Pratt, 1970;

. Meeting of Walnut Council/Northern Nut Tisserat et al., 1980) and incipient

Growers Association. Purdue University, infections by these fungi may contribute to

West Lafayette, Indiana, Aug. 9-14, 1981. subsequent root rot in the heel-in beds

2Graduate-Research Assistant and (Green and Ploetz, 1979). Root-infected

Professor's, Departments of Plant Pathology walnut transplants seldom survive

and Forestry, University of Wisconsin- outplanting to the field.

Madison, Madison, WI 53706, and R. F. Camp,

Manager, Wilson State Forest Nursery, Heavy losses of young walnuts due to

Wisconsin Department of Natural Resources, root deterioration in the heel-in beds have

Madisoni WI 53707. led managers to consider other methods of
storing_ seedlings. The purpose of our study one inch from the tip of the main tap 

was to evaluate several methods of was considered rotted. Healthy seedlings

overwinter storage and to identify some of showed little or no discoloration at th

the factors (both biotic and environmental) of the cut root, and were very firm in

contributing to this problem, texture. The cortex of healthy roots 

pearl-white in color. Discolored roots

appeared spongy and water-soaked. Thec

MATERIALS AND METHODS of the rotted roots ranged from light 

to black. In other cases, rotted roots

Studies have been conducted from 1978 showed sunken, irregular, black lesions 

through May, 1981, and are continuing, the tap root. Tissue samples were take

One-year-old black walnut seedlings raised from selected discolored roots,

at the Wilson State Forest Nursery, surface-sterilized in a 10% sodium

Boscobel, Wisconsin'were used in all hypochlorite solution for 2 minutes, a

studies. Seedlings were undercut approxi- plated on potato dextrose agar. Typical

mately 20 cm below the soil surfac_ the discolored samples also were placed dir

first week in November of each year. on VYS-PBNC, a selective medium for

' Undercut seedlings were hand-lifted, graded, Phytophthora species (Schmitthenner, 1

and bundled into groups of 20 or, 25 trees. Pathogenicity tests of the isolates we

Those trees which had a tap root of less made on one-year-old walnut seedlings

than 20 cm in length or a root system planted in 12-cm diameter clay pots in 

showing discoloration were culled prior to 2:1:1 (soil:sand:peat) mixture. Before

bundling. Spring-lifted (April) seedlings planting the seedlings, a small agar b

were handled similarly, containing mycelia of the selected fun

isolate was placed in a knife wound ma

Fall-lifted trees were stored overwinter the tap root. The seedlings were grown 

either in heel-in beds or in heavy paper the greenhouse for one month, then exam

shipping bags. The heel-in method consisted for root rot symptoms. Attempts were 

• of placing the bundled seedlings in trenches to reisolate the causal organism from 

30-45 cm deep dug in the seedbed. The roots rotted roots.

then were covered with soil. Trees were

overwintered in this manner until they were In 1979, all seedlings were outplan

lifted in the spring. Other fall-lifted, by hand at the Knap Creek Wildlife Are

bundled trees were placed in large shipping Boscobel, WI. In 1980, seedlings were

bags which were sewn or stapled shut. The outplanted at the Wilson State Forest

bags were stored over#inter in large walk-in Nursery. Transplant survival was recor

coolers maintained at a .constant 4 C. No in September of the planting year. Si

packing was added to the bagged seedlings, initial root rot and field survival we

except in one treatment where damp straw calculated as percentages of original

mulch was distributed among the bundles of seedlings, the data were transformed b

seedlings, arc sin method (Snedecor and Cochran, 

prior to analysis.

Fall-lifted seedlings were dipped in

fungicides prior to overwinter storage.

Bundled seedlings were immersed in one of • RESULTS

several experimental fungicides for

approximately ono minute in the 1978-79 Spring-lifting

experiments (Tisserat etI .... al., 1980). Two

chemicals were tested further, in the In earlier studies the incidence a

1979-80 and 1980-81 trials. The two severity of root rot were compared bet

fungicides Were benomyl (Benlate 50% WP) at fall-lifted seedlings overwintered in

5 lb active ingredient (a.i.)/100 gal water heel-in beds and undisturbed seedlings 

(6 g/l) and captafol (Difolatan 4F) at 4 Ib overwinter in the seedbeds. In some y

a.i./100 gal water (5 g/l). Seedlings not up to I00 percent loss occurred in the

treated, seedlings dipped in water only, and heel-in beds whereas little, if any, r

Spring-lifted seedlings served as controls, rot was found in spring-lifted seedling

A randomized complete block design was used. Therefore, since 1978, overwintering r

rot largely has been avoided by waiting

In all experiments, data were recorded until spring to lift the seedlings jus

on the incidence of root rot before before shipment.

outplanting and seedling survival after

outplanting. Any seedling showing root Unfortunately, seedlings left in t

lesions and/or discoloration greater than seedbed during the winter 1980-81, and
? °

spring-lifted in April, also suffered percentage (75%) of root rot. Addition of

extensive root deterioration. Surveys of

the seedbed showed that 60% of the seedlings ........

had complete root mortality and many of the

remaining trees had varying degrees of root Table I. Incidence of root rot in walnut

discoloration. Because the loss was so high seedlings following winter storage and

and identifying healthy trees was so survival after outplanting (1979-1980)

uncertain, the entire stock of black walnut

seedlings was condemned.

Storage method

Nevertheless, it appears that in most • Bagged Heel-in

years, seedlifigs may remain overwinter in 1979 1980 1979 1980

the seedbed, and may be spring-lifted Root rot_I/ 4.8 1.0 5.8 23.8

without heavy losses from root rot. However Survival 95.0 87.7 93.0 70.0

this method may be disastrous in some years,

as evidenced by the 1980-81 losses.

I/ Values are percent averages of 15

replicates, 25 seedlings per replicate,

STORAGE METHODS , 1979, and 30 replicates, 20 seedlings per

replicate, 1980.

At the time the experiments we re

conducted, there was some question as to

whether walnut seedlings would survive straw mulch (marsh hay to 60 cm depth) to

winter storage in the shipping bags. the heel-in beds resulted in reduced root

Results for all years show that fall-lifted rot. Seedlings stored in bags at 4 C had

seedlings survived overwinter storage at 4 C little or no root rot.

in Sealed bags in excellent condition. In

the 1979 plantings, little difference in Root rot incidence and subsequent

root rot incidence and survival was found survival of bagged seedlings were unaffected

between the fall-lifted and bagged seedlings by fungicide treatments (Tables 2 and 3).

or Seedlings overwintered in heel-in beds Seedlings with and without a water dip

(Table I). Seedling survival for all survived as well as did seedlings with a

heel-in treatments averaged 93% compared to fungicide dip. However, a sparse, but

95% for the bagged storage methods for that unsightly, covering of fungus mycelia 

particular year. In contrast, data from the occasionally developed on bagged seedlings.

1980 plantings indicated that the bagged Nevertheless roots were sound and the

seedlings had a lower percentage of-root rot superficial mycelia did not affect seedling

and

seedlings

a higher

from

survi

the

val

heel-in

rate t

treatments,

han did

benomyl

survival

and

after

captafol

outplan

fungicide

ting. Bot

dips

h the

red.uced

this molding of seedlings stored in the 

showed

Result

much

s from

larger

the

differences

1980-81 experiments

between

bag

treatment.

s, and may be desirable as a prestorage 

storage methods (Table 2). Fall-lifted

seedlings placed in heel-in beds to

overwinter without mulch had the highest 

Table 2 Incidence of root rot (%) of black walnut seedlings following

various overwinter storage methods and treatments, 1980-81.

Bagged Heel-in (fall)

No H20 Benomyl Captafol Straw Straw No

dip dip dip dip packing mulch mulch

I/

2. Oa 0. Oa O. Oa 1. Oa 2. Oa 7. Oa 7 5. Ob

I/ Mean percent root rot for 5 replicates, 20 seedlings per replicate.

Values not followed by the same letter differ significantly (p less than

.05.) according to FLSD test.

......

40
Table 3. Effect of chemical and cultural treatments on storage root rot

(winter 1979-80)and outplanting survival of walnut seedlings.

No dip H20 dip Straw Benomyl Captafol

Bag Hi_/ Bag Hi Bag Hi Bag Hi Bag Hi

Root rot(%) la_2/° 24d 0a 29e 0a 9b 0a 38f la 19c

Survival (%) 84b 68cd 85b 77c 94a 75c 92a 65d 83b 67d

I/ Fall-lifted heel-in treatments.

2/ Values represent an average of six replicates. Values in each row not

followed by the same letter differ significantly (p is less than .05)

according to FLSD test.

Associated Fungi study (Table I) was higher than that 

1978-79 experiments. Seedbeds during

The role of fungi in the "over winter 1978-79 had two to three feet of snow 

root rot" problem is unclear. Several fungi most of the winter while in 1979-80, 

were isolated from rotted roots stored in seedbeds had little or no snowcover t

heel-in beds during the winters of 1978-79 entire winter. Temperature extremes 

and 1979-80. The most common fungi found soil during 1979-80 and fluctuating s

were species of Fusarium, Trichoderma , and temperatures during the winter of 198

Aspergillus. Most of these fungi are not may have injured roots and predisposed 

• considered to be primary pathogens but can to attack by soil-borne microorganisms. 

cause damage to weakened or injured root contrast, bagged seedlings stored at 

systems. Primary pathogens such as (Table I) in both years had very litt

Cylindrocladium sp. and Phytophthora rot.

citricola were isolated less frequently from

decayed roots. In both these years, very

little root rot developed overwinter. CONCLUSIONS

Root rot during the 1980-81 winter was In past years, overwinter storage 

severe, resulting in the loss of the entire black walnut seedlings in heel-in beds

crop. Attempts to isolate pathogens from resulted in extensive root rot. Our 

discolored roots during April, 1981, showed suggest alternative methods for storag

that such roots were essentially sterile, black walnut seedlings during the wint

Only rarely were fungi or bacteria found in months. Spring-lifting and immediate

rotted tissue. Because no biotic agent was distribution of seedlings are preferab

isolated consistently, and the fact that the fall-lifting and heel-in method o

' fail-lifted seedlings in heavily mulched storage in avoiding overwinter root r

heel-in beds or stored in bags had very However, there is still occasional ri

little root rot (Table 2) make it doubtful involved in spring-lifting, depending 

that fungi were the primary causal agents of winter conditions. Spring-lifting sh

root rot for that year. used only where cold storage facilitie

not available. Moreover, fall-lifting 

Our results suggest that freezing cold storage may be more convenient f

temperatures or extreme fluctuations in nursery managers, enabling them to av

temperatures in the heel-in beds or even in spring rush in lifting other tree spe

seedbeds may be important factors in the

incidence of root rot. Initial studies Therefore, we believe that the be

indicated that bare-rooted seedlings exposed method of storage in Wisconsin is

to freezing temperatures (-12 C for 30 fall-lifting, placement of seedlings 

minutes) prior to storage were heavily sealed shipping bags, and overwinter 

colonized by Fusarium spp. and did not at 4 C. Care must be taken to keep t

survive outplanting the following year temperature at a constant 4 C, because

(Tisserat et al., 1980). The incidence of freezing temperatures result in direct

root rot in the heel-in beds for the 1979-80 damage to roots, a high incidence of 
i

°

I

I

rot, and poor field survival, methods for overwinter storage of black

Fungicide dip treatments of seedlings walnu 231.t Depseedlings. t. For., UniFor. versRes. ity NofoteWI.,No.

J prior to storage in bags at 4 C had little Madison. 6 p.

effect on root rot or field survival. No

dip or water dip controls also were Young, G. 1943. Root rots in storage of

, essentially free of root rot. However, the deciduous nursery stock and their

- benomyl and captafol dips did reduce control. Phytopathology 33:656-665.

: I sUperficial molding of walnut seedlings

stored in shipping bags. While the molding

did not affect survival of outplanted

seedlings, it was unsightly and could reduce

°" the marketability of bagged seedlings.

While methods for avoiding the root rot

problem during winter storage are now

available, the exact nature of the root

'deterioration is still unclear. It does

appear that c01d temperatures or extreme '

temperature fluctuations contribute to the

incidence and development of storage root

rot. either directly or indirectly. Whether

other factors such as incipient infections

by pathogenic fungi are involved is not

known. Future research will attempt to

clarify the reiative roles of abiotic

(environmental) and biotic agents.

LITERATURE CITED

Cordell, C., and Matuszewski, M. 1974.

Cylindrocladlum scoparium damaging black

walnut seedlings in Kentucky nurseries.

Plant Disease Reporter 58: 188-189.

Green, R. J., and Ploetz, R. C. 1_79. Root

rot of black walnut seedlings caused by

Phytophthora citricola. Pages 5-10 in

Walnut Insects and Diseases. Workshop

Proc., USDA For. Serv. Gen. Tech. Rep. 

• NC-52. I00 p.

Green, R. J., and Pratt, R. G. 1970. Root 

rot of-black walnut seedlings caused by

Phytophthora citricola. Plant Disease

• Reporter 54: 583-585.

Schlesinger, R. C., and Funk, D. T. 1977.

Manager's handbook for black walnut.

USDA For. Serv. Gen. Tech. Rep. NC-38. 

22 p. .

Schmitthenner, A. F. 1973. Proc. First

Woody Ornamental Disease Workshop 

11:94-110. . 

SnedecOr, G. W., and Cochran, W. G. 1967. 

Statistical Methods, 6th ed. Iowa State

Univ. Press, Ames. 593 p.

Tisserat, N., Guries, R., Kuntz, J., and

Camp, R. 1980. An evaluation of some

42
.

BLACK WALNUT CURCULIO:

A FACTOR IN WALNUT NUT PRODUCTION 1

2

Larry M. Blair

,

Abstract.--The black walnut curculio is discussed as

an important factor in premature nut loss of black walnut.

In Missouri trapping studies, nut drop resulting from curculio activity reduced potential harvestable yields by 19%

to 78% in three geographic areas of the state. Average

loss was 51%. A brief biology of the insect is presented.

J

Since World War II, new uses for nut The black walnut curcullo, Conotrach

shells and kernels of black walnut (Juglans retentus (Say), is an important insect p

ni__i_ L.) have created a growing demand for walnut nut crops (fig. I). The adult fe

black walnut nuts. Potential nut returns are new walnut shoots and leaves, and the la

an important addition to the value of the destroys developing nuts.

species. Management practices are being designed to improve growth conditions for nut

production as well as lumber. Revenues from

nut sales can be used to ease long-term

carrying costs associated with lengthy stand

rotations.

A major factor influencing demand for

nuts in recent years has been the shortage of

black walnut planting stock. Landowner

awareness of walnut values has caused a significant increase in the number of plantations

established. Most states have been unable to

produce enough seedlings to meet these de-

' mands because of nut scarcity (Grey, 1971).

The problem is complicated by competition

from the nut industry. Aside from the importance of black walnut kernels as a food item,

research has shown important uses for the

crushed Shells. Uses include filtering

agents in smoke-stack scrubbers, addltlvesto

dri11ing mud in oil-well dri11ing, and

polishing agents for chrome and automotive Figure l.--Adult walnut curcullo.

parts, among others (Cavender, 1973). In

. addition, Hammons Products Company in Previous research on this insect was lim

Stockton, Missouri, has recently been sucand revealed little about its habits and 

cessful in boosting nutritive values of history. Therefore, a research project 

cattle feed by adding low grade walnut ker- undertaken to study the curcullo's biolog

nels to a corn feed mixture. Continued reand impact on walnut nut production in

search promises addltional uses for black Missouri (Blair, 1978). walnut nuts in the future.

, LIFE HISTORY

Ipaper presented at the Black Walnut Adult curcullos spend the winter in 

Symposium, West LaFayette, Indiana, or heavy leaf litter near the base of wa

August 10-14, 1981. trees. Spring emergence is closely time

bud break, and occurs from mid to late A

2Larry M. Blair, Area Extension Newly emerged adults enter trees by craw

Forester, K.S.U. Area Extension Office, or flying. They feed on succulent foliag

South Hutchinson, Kansas. male flowers with feeding damage appearin
°

a,darkened-spot on the base of the leaf stalk. SHOOT PROBLEMS

It seldom causes leaf death, and is difficult

to detect. Other feeding damage may occa- Infrequently, eggs may be laid on develsionally appear as holes chewed in leaflets, oping shoots of black walnut. Stem mining and

However, this damage is similar to that of loss of terminal buds are potential growthother leaf-feeding beetles, and is not form problems on young trees. However, surdiagnostic, veys of Missouri walnut plantations under ten

years of age revealed no curculio activity.

Eggs are laid on developing nuts shortly Adult curculios probably do not associate with

after the female flowers are fertilized. When trees too young to bear nut crops.

nuts are small, single eggs are placed in

crescent-shaped punctures chewed from the nut

wall (fig. 2) . IMPACT ON NUT CROPS

_ := _ Missouri nut productivity studies were

..... conducted in one area in 1976, and three areas

" in 1977. The initial study involved testing

and comparison of three trapping designs at

the Dupont black walnut plantation near

Ashburn, Missouri. Trees in the plantation

were 27 years oldat the time of the study.

Thirty-slx trees were selected and sampled

with 216 cone-shaped plastic traps. Traps

were three feet in diameter, and each was suspended between two 5-foot stakes. Trap place-

_ 0_ ment was statistically designed tO accurately

estimate damage for the entire plantation from

,_ __ . sample tree collections.

_:_ _: _ ._

• ..

_ ' _........ __._._'_ ..... _:::_;" Traps were checked weekly from early June

until August, and biweekly for the remainder

Figure 2.--Oviposition mark on nut. of the season. The collected nuts were dissected to determine the reason for early drop.

Several eggs may hatch on a small nut, but Records were kept for each nut. Four factors

the most active larva consumes the others to were determined to influence premature abordefend its food supply. On larger, more tion and loss to nut crops. These included

maturenuts, single eggs are placed £n punc- curculio damage, infertility, squirrel actltures resembling pin holes. These punctures vity, and natural abortion in response to

are usually placed on the nut in clusters of moisture stress. Curculio damage had the

3 to I0. Large nuts may support the devel- greatest impact of the four factors. It acopment of several larvae, counted for 88% of the premature drop recorded 

Hatching usually occurs five days after during the two years of productivity studies.

eggs are la_d. Larvae bore into the watery Seasonal nut drop at the Dupont plantation 

•centers of developing nuts and feed exten- in 1976 occurred in two distinct periods (fig.3),

sive!y.. "June nutdrop" occurs when in-

• The "June nut drop" included all nuts Which 

fested nuts drop from trees in late May, dropped before August 17 as a result of the

June and early July. From the time the eggs four previously mentioned factors. These 

are laid, it takes about three weeks for nut nuts were lost to production. The mature nut

drop to occur. Most infested nuts abort when drop occurred from September 15 to November 5. 

, approximately _" in diameter. For this Nuts which dropped during this period were 

reason, the premature nut drop is easily harvestable. The black walnut curcullo reduced 

overlooked, the nut crop by 43% at Dupont in 1976.

Larvae remain inside hollowed-out nuts The 1977 black walnut productivity study

for an additional two weeks before entering

the soil to pupate. Nut exit holes are _" was expanded to include trapping sites in

• three geographic areas of the state. The

in diameter, and serve as evidence of cur- Dupont plantation was again used to represent

cullo activity. The pupal stage requires the northeastern part of Missouri. An unthree weeks and occurs at an average soll managed tract of black walnut near Fayette,

depth of two inches. After this, adult Missouri, was used as a central Missouri site.

curculios emerge and feed on black walnut The third site was an intensively managed

follage until leaf drop occurs. Only one black walnut fertilization plot in southwestern

generation is produced per year. Missouri, near Stockton. Sample trees were of i•!

44
°

nut, bearing age, and ranged from I0" to 12" A similar level of damage was record

DBH._ Thirty trees were randomly selected in at the Fayette trapping site (fig. 5). A

each area. Each tree was sampled with four more nuts were collected during the June 

traps, drop than during the mature drop. Sixty-six

percent of the crop was destroyed by curc

activity.

I" _ , 120"

I-

-20

110 17 24 • Lt 28 17 31 115 2 IS S

JUNI • JUD' AUG lil[Plr OCT NOV

14 28 12 26 9 14 28 12

JUNI Jul:r AUG SIEP/ OCT

Figure 3.--Seasonal distribution of black

• walnut nut drop at the Dupont plantation, Ashburn, Missouri, in 1976. Figure 5.--Seasonal distribution of black

walnut nut drop in natural forest, 

Seasonal nut drop at the Dupont planta- Fayette, Missouri, in 1977.

tion differed greatly in 1977 from that of the

previous season (fig. 4). Only a small per- The Stockton area was least affected 

centage of the nuts reached maturity. Cur- premature nut drop (fig. 6). Most of th

culio damage was responsible for a 78% reduc- crop reached maturity at this site. Curc

• tion of the potential harvestable yield, activity destroyed only 19% of the develo

nuts. 

29 115 20 29 • 1_1 27 • 31 19 20 31 14 21 S 18 28 17 • 27' 

MAr JUNE, JULY _ _ OCT MAY JUNI JUlY AUG _ O

Figure 4.--Seasonal distribution of black Figure 6.--Seasonal distribution of black 

walnut nut drop at the Dupont planta- nut nut drop at the Fox plantation,

tion, Ashburn, Missouri, in 1977. Stockton, Missouri, in 197.7.
This level of damage was not consistent with trol measures may be warranted in seed proother Missouri areas. The comparatively low duction areas, or where annual incomes from

impact was possibly linked with site distur- nut crops are desired. Continued research

bance effected by former practices in the is needed in developing a sound control pro- 

stand. Activities which affected the site gram to reduce the impact of this pest.

included annual applications of simazine and

paraquat to remove grass under trees, bulldozer work to release single trees, and the LITERATURE CITED 

Use of heavy equipment in an intensive spray

Schedule involving foliar fertilization. It Cavender, C.C. 1973. Utilization and marketis believed that the combination of compacted ing of shells. In Black Walnut as a Crop.

soil and lack of normal ground cover may have U.S. Dept. Agric. For. Service, North Cenadversely influenced curculio populations on tral For. Exp. Stn., St. Paul, Minnesota,

the site. This might explain the reduced p. 77-78.

level of curculio damage.

Grey, G.W. 1973. Seven years of growth. In

_ _ Black Walnut as a Crop. U.S. Dept. of 

CONCLUSIONS Agric. For. Service, North Central For. 

' Exp. Stn., St. Paul, Minnesota, p. 4-6. 

Seasonal nut collections in 1976 and 1977

showed that the black walnut curculio had an Blair L.M. 1978. The Bionomics of the Black

important impact on black walnut nut produc- Walnut Curcullo and its Impact on Walnut

tion in Missouri, Statewide, an average of Shoot Development and Nut Production.

51% of the nuts collected in productivity Masters Thesis, Dept. Entomology, Universtudies dropped prematurely as a result ofl sity Missouri - Columbia, 145 p.

curculio activity. This indicates that con- 

- ,

i

46
PHYSIOLOGY AND SILVICULTURE OF BLACK WALNUT FOR

COMBINED TIMBER AND NUT PRODUCTION

J. W. Van Sambeek and George Rink I

. . , .... , .-- -- _

A_stract.--Research literature was reviewed for evidence

supporting the management of black walnut plantations for

combined timber and nut production. The silviculture of the

species is discussed in relation to dual cropping. Stimulation and phenology of flowering and fruiting are reviewed.

, , , ,, , ,

Walnut growers face the same economic Initial tree spacing in plantations

vagaries as other businessmen. The recent intended for combined nut and timber productio

surges in the cost of capital have made stand- is recommended to be 15 to 20 feet square C

ard economic forecasts obsolete. Current pared to 10 to 12 feet square for timber alo

inflated interest rates may make plantation Planting trees at a close spacing provides 

establlshment costs prohibitive when projected opportunity for selection of superior crop

over the length of walnut rotations. Nut crops trees. It also necessitates an earlier thi

could provide one source of early income to (Schlesinger and Funk 1977, Funk et al. 197

offset such costs (Kincald and Kurtz 1981).

A criterion for determining the necessi

Industries marketing nut meats and shells and timing of thinning is crown competition

would llke a more regular yearly volume of nuts, factor (CCF). For nut production, the CCF

although walnut is considered a falrly consist- should not exceed 90. A CCF of 90 means th

ent bearer (Wylie 1966). Managers of seed the plantatlon will have to be thinned when 

orchards also need methods for enhancing nut total crown area covers 90 percent of the p

production if they are to annually supply nut- tation's land surface (Schleslnger and Funk

series with genetlcally improved seed. 1977). The plantatlon may have to be thinne

three or more times during a rotation. For

Evidence is presented showing that walnut example, in simulating an 80-year rotation,

can be managed for timber and improved nut Foster and Kung (1980) proposed thinning a 

yields, tatlon six times. With a 20-foot-square sp

the first thinning (around age 20) would be

after the trees have begun flowerlng and fr

MANAGEMENT STRATEGIES FOR TIMBER AND NUTS ing. Crop trees £ould be selected on the b

of seed production, seed quality and stem f

Maximizing timber yleld confllcts with

maximizing nut yields. Maximizing production Lateral pruning should begin when the 

of quality timber requires greater stem pruning are i0 to 15 feet tall (approximately age 5

and closer spacing of trees to favor a longer should be continued in stages until more th

branch-free bole, while increasing nut yleld feet of clear stemwood is obtained on every 

involves growing trees at a wider spacing to tree. The length of clear stem should not

favor larger tree crowns. Optimizing both nut exceed 50 to 60 percent of total tree heigh

and timber production involves compromises in Only crop trees need to be pruned. Correcti

spacing as well as in timing and extent of pruning will probably not be necessary beca

pruning (Schleslnger and Funk 1977). trees with poor form will be removed during

thlnnings (Schlesinger, in press).

No research data are available on comb

° nut and timber production from walnut plant

1Research Plant Physiologist and Research tlons. Using simulation techniques, Foster 

Plant Geneticist, respectlvely, North Central Kung (1980) compared the economic efficiency 

Forest Experiment Station, Forestry Sciences managing for combined nut and timber produc

Laboratory, Carbondale, Illlnols. versus managing for timber alone. They fou

.
4

that managing for combined nut and timber Foster and Kung's projection (fig. i), an 80-

production was more profitable than managing year-old walnut with an average annual diameter

for timber alone, as long as the annual com- growth rate of 0.33 in/yr should produce about

pound interest rate exceeded 6 3/4 percent and 3,100 pounds of alr-drled, hulled nuts during 

rotations were longer than 40 years. Similar its lifetime. This equals about 11,600 pounds

conclusions have been made by Wylle (1966), of unhulled nuts (Funk and Polak 1979). Life- 

Ca!lahanand Smith (1974), Garrett and Kurtz time nut production will reduce potential stem 

(1980), and Kincald and Kurtz (1981) using diameter from 27.4 to 26 inches. This reduction

different economic and tree growth assumptions, equals 4 or 5 years of growth or about 18 board

feet in the 8-foot veneer log. The value of 

Most projections for diameter growth the nut crop at current prices substantially

assume it is a linear function of age with an exceeds the value of lost diameter growth for

average annual increment of 0.33 in/yr (Naughton average grade walnut veneer logs. Shortening

1970), 0.33 to 0.5 in/yr (Garrett and Zurtz the rotation length can reduce both nut produc1980), or up to 0.56 in/yr (Wylie 1966). Pro- tion and its potential effect on diameter growth. 

jections _or nut yields as a linear function of

diameter at breast height for open-grown trees Management guidelines are now available 

are illustrated in figure 1 (Foster and Kung for improving diameter growth of black walnut 

1980, Garrett and Kurtz 1980). ' on marginal sites (Schlesinger and Funk 1977).

But what little information is available about

improving nut yields has not been tested. Before

sso- we can reasonably expect to manipulate stands to

improve nut yields, we must understand the

physiology of flowering and fruiting for walnut.

h Most research on flowering and fruiting in

Juglandaceae has been with English walnut and

= pecan, but it is assumed that much of this

•Ze so¢ - information also applies to black walnut.

a ••• 

-.. .• FLOWERING BIOLOGY

O - ••

_ " Black walnut normally begins flowering

***• about mid-April in the southern part of the

= s_ - ** range and mid-June in the northern part of the

o ** range, although within individual stands trees 

I •s •

_ .* may vary by as much as a month in flowering

** mately the same time, early enough for p6ssible 

- dates (Masters 1974, McDaniel 1956). Flower

development and leafing out occur at approxii

I I I I I l damage by late spring frosts (fig. 2). PolliI o so 2o so nation and fertilization normally occur a few

, Ononotor ot broaot honght (Inchoo) weeks after the mean frost-free date and are

i less likely to be affected by late spring frosts

Figure l--Projections of a_erage nut production Walnuts bear separate male and female

by different diameter walnut trees. Solid flowers on the same tree. Self-pollination is

line is for alr-dried weight after Foster and unlikely, however, because flowers of different

Kung (1980); dashed llne for freshly hulled sexes normally mature at different times;

weight after Garrett and Kurtz (1980). female flowers most often precede the males.

' " However, spring floral development is definitely

' temperature dependent and warm temperatures at

} one concern sometimes raised about combined the time of flowering tend to increase the over-

._ timber and nutproductlon is that potential tree lap between male and female flower maturation

, growthmay be diverted into a nut crop, possibly (Masters 1974).

- resulting insmaller trees. For apple trees

* (8 to 9 inches dbh) the stem cross sectional Male flowers are found on wood grown in

' area lost due to fruit production is approxi- the previous season; they are initiated in

' mately 0.005 square inch per pound of fruit vegetative buds during the period of rapid

(Webster and Brown 1980). Because no such wal- shoot elongation early in the growing season of

nut data are available, it will be assumed that the previous year. Female flowers are found at

the reduction in walnut growth due to fruiting the tip of the current growing shoot, developing

is similar to that of apples. According to in dormant buds set after completion of the

48
- FIRST YEAR • Female flower initiation

-- - Male flower initiation --

u. Avg. frost free date / /

80- F

" _ 60

40- t elongation

< 20 I I I I I I I I I I I 

SECOND YEAR

.

u. Pollination Nut release

at 8 0 -- :.:.:.:.: ..............

• ................... :::;:::__:i:i:

so E

e

• _ 40

• =: Fruit enlargement el S • I hardening

< 2o I I i I I I I I I I I 

January March May July September November

MONTH

- 

Figure 2.--Sequence of flower development, pollination, and nut maturation for black walnu

southern llllnois

previous year's growth (fig. 2) (Ramlna 1969, delay bud break by as much as 6 to 12 da

Masters 1974, Funk 1978). thereby decreasing the probability of da

new growth and flowers (Wolstenholme 197

Several factors influence flowering abun- Overtree irrigation in the spring will a

dance. All flowers are essentially borne on delay bud break and flowering from 5 to 

the crown surface. Any cultural practices (Belneke and Hunley 1979).

increasing the crown surface area, or number

of new branches, will increase the number of Little research has been done on th

, potential flowering sites. In English walnut of chemical sprays to alter new shoot gr

the number of female flowers increases as growth and subsequent flower production. Marth 

is increased (Link 1961). Likewise, increased Mitchell (1961) found that glbberellin t

nut yields in black walnut in response to fer- ments promoted walnut shoot elongation. 

tiiization (Ponder 1979) and weed control (Holt spray application may also increase flow

and Voeller 1973) may be related to improved production through improved branch growth

vigor resulting in more branches and branch Langrova and Sladky (1971) found that au

growth and consequently more flower production, containing sprays applied to English wal

• when male flowers were forming decreased 

Late spring frosts often reduce the num- number of catkins formed the following y

bet of flowers reaching maturity. Compared anti-auxin sprays applied after male flo

With clean cultivation, maintenance of legumi- formed increased the number of catkins, 

nous or grass covers in walnut plantations may of which contained female flowers. The

. 
°

formation Of male and female flowers is 3 weeks sooner, and the sprayed trees produce

apparently controlled by the interaction of higher quality nuts than the unsprayed trees

gibberelllns, auxins, and growth inhibitors (Martin 1971, Sibbett et el. 1974). Another

within the developing shoots (Sladky 1974). alternative may be underplanting with legumiFurther research is needed on cultural and nous winter annuals to accelerate tree dormancy

chemlcal methods to stimulate flower formation (Auchter and Knapp 1937).

and*nutdevelopment.

The minimum seed-bearing age for commercial

quantities of nuts is about 12 years, although

FRUITING BIOLOGY open-grown trees produce some seeds as early as

4 years after outplantlng (Schlesinger and Funk

Fertilization occurs within 2 to 5 days 1977). The biggest challenge in managing walof pollination, followed by a period of rapid nut for timber and nut production is to mainexpansion of the fruit during the next 5 to 6 rain regular annual yields. On open-grown

weeks (fig. 2). Fruits increase in weight sub- trees, nut crops are produced most commonly in

srantially before entering the shell-hardening an alternate-year cycle; some trees bear

stage in early July, although increases in size annually, others bear in i or 2 years out of 3,

are not noticeable at this time. During the and many bear with no regular pattern at all

latter part of the shell-hardenlng stage (late (Zarger et al. 1969). Alternate bearing is

July), the embryo and cotyledons begin to characteristic of most fruit trees with lateenlarge rapidly, incorporating most of the season fruit maturation and is related to the

pr_vlously deposited endosperm. The kernel, carbohydrate concentration in the plant (Sparks

composed of the embryo and cotyledons, usually 1979). Late-season kernel development makes a

does not developuntil 4 to 5 weeks before the high demand on available carbohydrates and

nuts are mature. By late August, some nuts stored reserves when the new female flowers

cangermlnate after stratification. Most nuts, are forming. Increasing the leaf area per unit

however, continue to increase in dry weight of fruit may decrease the alternate bearing

• and do not drop from the tree until shortly tendency (Sparks 1979). Before thinning plan- 

after leaf fall in late September or early tatlons, the manager may be able to identify

october, those trees with good form that are persi§tent

bearers or trees that produce crops during "off"

Once the nutlets are formed, nutlet loss years. Wylie (1966) suggested annually spot

is usually due to disease or insect infestations, painting trees that have above-average nut

Blair and Kearby (1979) found that more than 50 yields for a period of 5 to i0 years before

percent of the potential nut crop in Missouri thinning to facilitate crop tree selection.

walnut plantations was destroyed by-the walnut •

curculio. Epidemics of walnut anthracnose early Nut quality should also be considered when

in the growing season can cause significant nut- selecting trees for yields. Kernel percentage,

let losses; later or less severe disease out- the dry weight of kernel as a percent of the

breaks lead to poor nut filling and darkened dry weight of the entire nut, is the key factor

kernels called ambers (Funk 1979). in nut quality and should be more than 20 percent (Funk 1979). Such nuts can be expected to

Summer droughts can also lead to poor command a higher price (Garrett and Kurtz 1980).

filling of the kernels and may also delay seed

maturity (Batchelor et el.. 1945, Crane 1949).

Jones (1975) found that June, July, and August CONCLUSIONS

rainfall is an important variable in predicting

annual nut crops in southwest Missouri. Irri- Managing for nuts and timber requires a

gatlon during August and September may be lower level of stocking than for timber alone

important for high nut yields, because these to ensure rapid growth of large-crowned trees.

months often include long dry spells. The landowner must also prune trees to a minimum

clear height of 9 feet and select for higher nut

Early fall frosts can injurenew growth yielding trees before the last pre-commercial

before it is completely lignlfied, preventing thinning.

complete nut development and causing undesirable

shrivel (FUnk 1979). Thls frost danger is Managers of seed orchards must select trees

especially pertinent because recommendations for rapid growth and nut production to provide

| forcollectlng seed 200 miles south of the landowners with the desired types. Also, they

planting site for greater timber production may mayhave to select for late bud break and use

! result in immature nut crops (Sparks 1981). techniques like overtree irrigation and herbaceous 

| This problem may possibly be overcome by cheml- cover crops to delay bud break and flowering.

cal treatment. In English walnuts, fall spraying Late-summer irrigation may be needed to ensure

with ethephon produces a mature nut crop i to proper kernel development, and chemical ripeners

may be used to ensure a harvest of mature nuts.

!

"50
o

o

LITERATURE CITED Langrova, V. and Z. Sladky. 1971. The ro

of growth regulators in the differentiati

Auchter, E. C. and H. B. Knapp. 1937. Orchard of walnut buds (Juglans regia). Biol. 

and small fruit culture. 3rd ed. John Wiley 13(5-6):361-367.

and Sons, Inc., NY. 627 p. Link, H. 1961. [Information on the flower

Batchelor, L. S., O. L. Braucher, and E.F. biology of the walnut tree, Juglans re_i

Serr. 1945. Walnut production in California. Diss. Landw. Hochsch., Hohenheim. 78 p

Calif. Agrlc. Exp. Stn. Circ. 364, 34 p. McDaniel, J. C. 1957. The pollination of

Beineke, Walter F. and Jimmy L. Hunley. 1979. Juglandaceae varieties--Illinois observa

belay of floral and leaf development of and review of earlier studies. North. 

overtree irrigation in black walnut. Can. Grow. Assoc. Annu. Rep. 47(1956):118-132.

J. For. Res. 9:379-382. Marth, Paul C. and John W. Mitchell. 1961

Blair, Larry M. and WilllamH. Kearby. 1979. Growth regulators, stimulants and seeds

The black walnut curculio and its impact on p. 51-56. l__nSeeds. U. S. Dep. Agric.

nut production, p. 51-54. In Walnut Insects Yearbook for 1961.

and Diseases. Workshop Proceedlngs, June 13- Martin, G. C. 1971. 2-chloroethylphosphonic

_ _ 14, 1978, _arbondale, IL. U. S. Dep. Agric. acid as an aid to mechanical harvesting 

For. Serv. Gen. Tech. Rep. NC-52. English walnuts. Amer. Soc. Hort. Sci. 

Callahan, ° John C. and Robert P. Smith. 1974. 96(4):434-436.

An economic analysis of black walnut plan- Masters, Charles J. 1974. The controlled

ration enterprises. Purdue Univ. Res. Bull. pollination techniques and analysis of 

912, 20 p. speciflc hybrids for black walnut (Ju_la

Crane, H. L. i949. The development and filling ni_L.). Ph.D. Thesis, Purdue Univ. 

of nuts. North. Nut Grow. Assoc. Annu. Rep. Naughton, Gary G. 1970. Growth and yield 

39(1948):130-139. black walnut plantations. Kansas State 

Foster, Lawrence H. and Fan H. Kung. 1980. Ext. Serv., ii p.

Economic efficiency of two pruning heights Ponder, Felix, Jr. 1979. Fertilization a

in black walnut, p. 390-400. l_n_nCent, release increases nut production of pole

Hardwood For. Conf. III, Sept. 1980, Columbia, size black walnut, p. 138-144. In Proc

MO. ings of Symposium on Flowering and---Seed

Funk, David T. 1978. Genetics of black walnut Development in Trees (Frank Bonner, ed.)

(Juglans nlgra) (revised). U. S. Dep. Agric. Starkville, MS., May 1979.

For. Serv. Res. Pap. WO-10, 13 p. Ramlna, A. 1969. [Studies of the floral b

Funk, David T. 1979. Black walnuts for nuts and fruiting of walnuts (Juglans regia). 

and timber, p. 51-73. __InNut Tree Culture Flower bud differentiation.] Riv. Ortoin North America (Richard A. Jaynes, ed.). florofruttlc. 53:480-489.

• , North. Nut Grow. Assoc., _nc., Hamden, CT. Schiesinger, Richard C. 198 . Pruning for

Funk, David T. and David J. Polak. 1979. Notes quality. (In press.)

on the weight of black walnut. North. Nut Schlesinger, Richard C. and David T. Funk.

Grow. Assoc. Annu. Rep. 59:63-65. 1977. Manager's handbook for black waln

Funk, David T., Richard C. Schleslnger, and USDA For. Serv. GTR NC-38, 22 p. North

David J. Polak. 1978. Value gains from Central For. Exp. Stn., St. Paul, MN.

selective thinning of Juglansni_i_. p. 286- Sibbett, G. S., and others. 1974. Walnut

297. l__nnProc.Symp. on Establishment and quality and value maximized by harvest

Treatment of High-Quality Hardwood Forests management. Calif. Agric. 28(7):15-17.

• in the Temperate Climatic Region, Nancy, Sladky, Z. 1974. Experimental study of fl

France, Sept. 11-15, 1978. morphogenesis. III. Study of developmen

Garrett, H. E. and W. B. Kurtz. 1980. Black possibilities of leaf and floral prlmordi

walnut multicropping management. Walnut and the origin of fruits in Juglans regl

Council Bull. 7(1):15-19. Preslle 46(3):193-197.

Holt, Harvey A. and Jack E. Voeller. 1973. Sparks, Archie. 1981. Walnuts as a crop.

. Vegetation management increases production Walnut Council Bull. 8(1):3-4.

in nut orchards, p. 81-83. l_n_nBlackWalnut Sparks, Darrell. 1979. Physiology--site, 

as a Crop. Black Walnut Symp., Carbondale, flowering, fruiting, and nutrition, p. 

IL U.S. Dep. Agrlc. For. Serv. Gen. Tech. 239. In Nut Tree Culture in North Amerl

Rep. NC-4. (Richard A. Jaynes, ed.). North. Nut Gr

Jones, James E. _975. Factors which influence Assoc., Inc., Hamden, Ct.

regional nut production of eastern black Webster, D. H. and G. L. Brown. 1980. Tru

walnut. North. Nut Grow. Assoc. Annu. Rep. growth of apple tree as affected by crop

• 66(1):108-113. load. Can. J. Plant Scl. 60(4):1383-1391

Kincaid, Warren H. and William B. Kurtz. 1981. Wolstenholme, B. N. 1970. Pattern of bud 

Costs of black walnut management. Walnut in a pecan cultlvar/cultural experiment 

Council Bull. 8(1):5-6. dry land conditions. Agroplantae 2:61-66

0

......... l!lIII IIII I I I" IIIIIFIIII I1 I .
o

Wylie, John E. I966. Nuts and wood--dual crops

for management, p. 91-94. I__nBlack n Walnut

Culture. Proceedings of Black Walnut SymposiUm, Carbondale, IL, Augl 14-16, 1966. U.S.

Dep. Agric. For. Serv., North Cent. For. Exp.

Stn., St. Paul, DIN.

Zarger, T. G., R. E. Farmer, Jr., and K. A.

Taft, Jr. 1969. Natural variation in seed

characteristics and seed yield of black walnut in the Tennessee Valley. South. Conf.

For. Tree !mprov. Proc. 10:34-40.

52

_m
NUT PRODUCTION--A VALUABLE ASSET IN

1

. BLACK WALNUT MANAGEMENT

Harold E. Garrett and William B. Kurtz 2

Abstract.--Black walnut nut production is a viable

source of income for landowners involved in black walnut

management. An evaluation of the impact of nut production on economic yields of two management options, timber

°_ " vs. timber and nuts (timber option) and timber and wheat

vs. timber, wheat and nuts (multicropping option) revealed

greater economic returns from management regimes including

nut production. Increases in internal rate of return (IRR)

and present net worth (PNW) ranged from 0.5 to 2.2 percent

" and $438 to $2844, respectively, depending on management

option and nut prices.

Eastern black walnut is regarded as one groves. However, as high as $24.00 per 

of the most valued of American native woods, has been paid for plantation-grown nuts. 

Its wide use in the production of furniture, ferences in prices arise from difference

wall paneling, and gunstocks has resulted in percentage crackability. Nuts from natu

substantial literature detailing the economic stands, under commercial processing, yie

virtues of producing high quality veneer and average of only eight pounds of kernels 

sawlogs (Schlesinger and Funk 1977). However, cwt. of hulled nuts. With plantation c

little has been written on the economics of tions, a yield of 20 or more pounds of 

black walnut nut production. This is somewhat per cwt. is projected at a significantly 

of an anomaly in view of the fact that one of value.

the economic advantages of planting black walnut over other hardwood species is that it To evaluate the economic importance 

produces a marketable nut crop of considerable production in walnut management, potenti

value. Although Mattoon and Reed (1924) sug- gains with and without nuts from two ba

gested that "for the present the nut crop of management options (timber and multicrop

the black walnut should be regarded only as are compared.

incidental to the general farm operation--a

by-product of the farm and not a staple crop,"

this does not hold in 1981. An available MANAGE_NT ALTERNATIVES AND ASSUMPTIO

market for the sale of nuts exists in most

states Where black walnut is grown with the There are countless walnut manageme

demand for nuts exceeding the supply, tlons which can be designed to accomodat

objectives of the landowner within limi

With intensive management, black walnut of the site. For the purpose of evaluat

will produce commercial nut crops on all sites impact of nut production on economic yi

' by age 20 and will produce commercial crops on comparison was made within two basic op

many by age 15. In recent years nut values timber vs. timber and nuts (timber optio

have ranged from $3-$5.00 per hundred pound timber mud wheat vs. timber, wheat and 

• weight (cwt) for nuts collected from native (multlcropping option). These alternati

were developed using conditions relating 

black walnut production in Missouri but 

plicable throughout the natural range o

_aper presented at the Walnut Council/ species. Factors considered are site q

NNGA Symposium, West Lafayette, Indiana, diameter growth rate, number of trees p

August 9-14, 1981. per acre, pruning height and thinning r

The reader is referred to Fincaid et al

_rofessors of forestry, University of (1981) for specific details on these fa

Missouri- Co lumb ia.
For this comparison site qfiallty and ro- cover a fluctuatlng market. Nut ylelds (Table

tatlon length are held constant. A site in- 1) are also intentionally conservative in an

dex of 80 is assumed with a projected average attempt to offset the unknown cost of harvestdiameter growth rate of I/2-1nch per year. A Ing.

rotation length of 60 years was selected for

all management alternatives. Thinning recommendations are based on projected diameter Table 1.--Projected nut ylelds from black walclasses and crown competition factors (CCF- nut under plantation management.

Schleslnger and Funk 1977) resultlng in precommercial and conmerclal thlnnlngs.

AVE dbh Estlmated yield 1

Timber (inches) (pounds of hulled

• nuts/acre)

Black walnut is a species of great gene- 11.0 2128

tic variation. Because of Its variability, 13.5 2286

it_is important in timber production to utl- 15.5 2238

llze a close spacing, securing selectlon gain 18.5 2937

through thinning. While the spacing may vary' 22.5 2937

with site and specific management objective,

a spacing of 12 x 12 feet (300 stems/acre) has 27.5 2916

been selected for this analysis. Forty trees 32.5 2916

are selected for a first pruning to a height 1After ,V.lncald,W. H., 1981. Economlc-s_iviof nine feet at age eight. A second pruning

of 27 crop trees (to be selected from the culture aspects of black walnut management,

M.S. Thesis, School of Forcstry, Fisheries

orlglnal 40) is conducted at age 16 to a height

and Wildllfe, University of Missouri-Columbla.

of 17 feet. Through selective thinning, the (Yield estimates derived by llnear regression

•number of trees are reduced to 27 (approximately 40 x 40 feet) by rotation end. A maxl- from Zarger (1946) and increased by fifty

mlzatlon of log quality is achieved through percent to account for increased y_eld from

artificial prunlng, plantatlcn management .)

Timber and Nuts Timber and Wheat

Growing walnut for timber and nuts re- A timber and wheat management regime asquires the use of a wider spacing than grow- sumes plantatlon establlshment and management

practices similar to those of the timber and

Ing" trees for timber alone. This is importi ant to develop a large, relatively uninhibited nuts altematlve--i.e., number of trees per

crown. Therefore, a 40 x 10-foot spacing acre, thinning schedules, pruning heights,

growth and nut ylelds are unchanged However

i providing 108 trees per acre was selected " '

" an in_ercrop of winter wheat is grown between

As in timber production, selection gain is walnut rows for the first ten years. Although

achieved through precommerclal and commercial

thlnnlngs applied to reduce the number of wheat could be produced over a longer period

. without significant yield reductions resulting

trees to 27 by age 33. Clear-length pruning from walnut competition, in our analysis it is

Within this regime differs-from the pure timprojected for only ten years due to practical

ber regime in that the management objective considerations relative to management. In

is a shorter log with greater emphasis placed growing wheat, a minimum of three feet is left

' on crown size for nut production. At age ten, between the crop and trees. This land is re40 trees are pruned to a height of 9 feet. As moved from production to minimize competition

i in the timber management regime, 27 crop trees in the early spring and to reduce damage to

are SeleCted for a second pruning. Pruning the walnut root system that might occur during

occurs at age 20 and extends the clear length site preparation. of the stem to 15 feet.

Nut pr!cesare projected at $5,00, $9.00, Timber, Nuts and Wheat

$15.00 and $20.00 per hundred pound weight of

hulled nuts. The prices are conservative in- Timber and wheat establishment and manvlew of the fact that $24.00 per cwt has been agement practices, and costs and revenues are

paid Inrecent years for plantatlon grown nuts the same for both the timber, nuts and wheat

(personal communication, Gus Rutledge, Hammons and timber and wheat regimes. However, the

Products Co., Stockton, Missourl). However, timber, nuts and wheat regime does have the

it provides a reasonable range of prices to

54

p=sm
°

" additional benefit of nut yields which are With increased nut prices, the respe

assumed to be the same as from timber and IRRs for the two regimes including nut pr

nuts. tion would increase by i to 6 percent ove

$5.00 to $20.00 per cwt. price range (Tab

ECONOMIC EVALUATION For the timber and nuts regime an increas

PNW of $2321 per acre and for the timber, 

The economic contribution of nut produc- and wheat regime an increase in PNW of $2

tion to a black walnut management scheme was per acre would result from the increase 

assessed by comparing the internal rates of prices. Obviously, the resultant increas

return (IRR) and present net worth (PNW)gene- the financial return measures are linked 

rated by cash flows from the two basic manage- ly to the expected nut yields of the resp

ment options with and without nut production, regimes.

As indicated previously, nut prices of $5.00,

$9.00, $15.00 and $20.00 per cwt. were used The sensitivity of IRR relative to 

in evaluating the two options that included in nut yields was examined to determine 

nut production. All other prices are the same fects of such variations on the stability 

as those shown in Kincaid et al. (1981). Wal- IRR for the two regimes incorporating nut 

_nut stumpage prices for commercial thinning duction (Table 3). Since IRR is condition

and final harvest material were inflated at product price, it becomes more sensitive 

an annual rate of 1.5 percent (Hoover 1978). yield changes as nut price is increased. 

example, at the lower nut price of $5.00 

Greater economic returns were realized cwt. ann_al nut yield would have to be in

from those management regimes including nut ed by well over one-and-one-half times fo

production (Table 2). For both the timber ther regime to increase IRR by one percen

and the multicropping options nut production I_ contrast, at a nut price of $20.00 per 

accounted for an addition to IRR of from 0.5 annual nut yields would only have to incr

to 2.2 percent depending on nut prices. In a by just over one-half to increase IRR by 

similar fashion, increases in PNW ranged from percent.

$523 to $2844 per acre for the timber option

• and from $438 to $2598 per acre for the mul- Conclusions

ticropping option. The slightly higher levels

of difference in PNW for the timber option Management of black walnut stands fo

over the multicropping option are due to the production in conjunction with timber pro

additional costs incurred in establishing and tion or a multicropping alternative is cl

precommercially thinning the extra 192 trees to one's financial advantage. Higher ret

required in the timber regime--costs that are are yielded by those management regimes 

not offset by the greater stumpage yields for porating nut production in comparison to 

commercial thinning and final harvest in the which do not. Depending on assumed nut p

timber regime, increases in P NW of from $400 to $2900 pe

Table 2.--Internal rate of return I (IRR) and present net worth 2 (PNW) of four alternative blac

walnut management regimes at nut prices of $5, $9, $15, and $20 per cwt.

Management $5 $9 $15 $20

• regime IRR PNW IRR PNW IRR PNW IRR P NW

(Pct) ($ per ac.): (Pc_) ($ per ac.) (Pct) ($ per ac.) (Pct) ($ per 

Timber 6.68 2471.94 6.68 2471.94 6.68 2471.94 6.68 2471.

Timber and nuts 7.27 299_.74 7.71 3613.65 8.33 4542.03 8.81 5315.

Timber and wheat 8.20 3344.89. 8.20 3344.89 8.20 3344.89 8.20 3344.

Timber, nuts and wheat 8.74 3782.68 9.23 4358.62 9.91 5222.52 10.42 5942.

IInternal rate of return is the average interest rate earned on all costs up until the time of

investment maturity

Present net worth is the net value of the stream of costs and revenues discounted back to the

• present at a 5.0 percent interest rate.
I

Table 3.--Sensitivity of internal rate of return to changes

in nut yields for two black walnut management regimes at

nut prices of $5, $9, $15 and $20 per cwt.

Management $5 $9 $15 $20

- regime

.... .. . .. ,

........ Per cent---- "----------'

Timber and nuts 189.33 110.57 72.08 58.15

Timber, nuts and wheat 168.35 I01.14 68.52 56.79

Isensitivity is expressed as the percent increase in annual

nut yield required to increase internal rate of return by 1.0 percent.

j

acre may be attributable to the value of nuts black walnut nut meat is presently sold only 

produced over the 60-year rotation, as a flavoring agent and little or no consideration has been made for its nutritional

.Nut production in a multicropping regime value, the extractable fat from the nut meat

--timber, nuts and wheat, in this instance-- or the export market, the potential market for

offers the greatest financial returns of those eastern black walnut kernels has hardly been

alternatives considered due to the earlier re- tapped. In light of this, a market demand of

turns from crop yields, later supplemented by 200 million pounds per year is not considered 

nut yields. In comparison to the timber and to be unrealistic.

nuts management regime, the multicropping re-

• gime including nuts generates additional PNW These are encouraging results for black 

•

of $60.0 to $800 per acre depending on assumed walnut growers. By emphasizing nut production,

nut prices, an additional reliable source of income is

available for the majority of the rotation 

The financial success of managing for nut period.

production is directly linked to the price of

nuts. Obviously, the higher the price received L_TERATURE CITED

i prth_oe duc mortio e n.profiAltable thoughwillnot becommaplenagtelement y, supfpoorrtn-ut Hoover, W. L. 1978. Walnut log prices, Wall able, given the present and the anticipated nut Council Member Newsletter. March,

I supply,demand situation for black walnut nut 1978, 5(1):3-4.

! meats, it is quite likely that the price paid Kincaid, W. H., W. B. Kurtz and H. E. Garrett.

': for quality hulled nuts will experience a con- 1981. A silvicultural-economic model for 

tinued rise. black walnut. In Proceedings of Walnut

Council/NNGA symposium, West Lafayette,

Our view is based on the many potential 3ndiana, August 9-15 (in press).

" .- uses for hulls, and nut meats as well as cur- Mattoon, W. R. and C. A. Reed. 1924. Black

rent market requirements which are not being walnut for timber and nuts. USDA Farmers'

met. In good. cropyears, H-_mmons Products Bull. 1392, 30 p. Washington, D.C.

• Company, Stockton, Missouri, the Gravett Shell- Schlesinger, R. C. and D. T. Funk. 1977.

!ng Company, a Division of Hammons Products, Manager's handbook for black walnut. USDA

Gravett, Arkansas, and Funsten Nut Division of For. Serv. Gen. Tech. Rep. NC-38, 22 p.

Pet, Inc., Bolivar, Missouri, the major put- North Cent. For. Exp. Stn., St. Paul,

chasers, of eastern black walnut nuts attempt Minnesota.

to buy a total of approximately 60 million Zarger, T. G. 1946. Yield and nut quality of

pounds of hulled nuts. Only rarely is this the common black walnut in the Tennessee

achieved. In 1980, only four million pounds valley. Northern Nut Growers Association,

were available for purchase. Since eastern 37th Ann. Rep., p. 118-124.

56
°

THE STATUS OF BLACK WALNUT TREE IMPROVEMENT PROGRAMS

, .

IN THE NORTI-I CENTRAL REGION

George Rink and Henry E. Stelzer I

Abstract.--Black walnut was found to be a high priority

species for improvement in Central and North Central United

States. Most State improvement programs have as their goal

_ the ability to meet seedling requirements with improved

seed. States included in this report may have orchard acreage sufficient to,meet this goal. Anticipated year of production of improved seed from seed orchards and seedling

demand projections are presented by States.

INTRODUCTION INFORMATION SURVEY

Genetic improvement of black walnut has Questionnaires were mailed to II Sta

been advocated for at least 20 years. Although agencies or universities in the commercial

Wright (1966) outlined several approaches to range of black walnut requesting informati

• such improvement, he felt that a basic improve- on current status and future plans for th

ment program to include selection, provenance, species. States included in this informal 

and progeny testing would be the most efficient vey were Illinois, Iowa, Indiana, Kansas,

and productive approach in the long run. Kentucky, Michigan, Minnesota, Missouri, 

Tennessee, and Wisconsin. Although other

Although the feasibility of genetic states in the East and Northeast produce 

improvement of walnut is fairly well docu- nut seedlings, most of their activities a

mented by research, the application of research centered around growing walnut in an urba

results has apparently lagged behind (Bey 1973, ring or for nut production. These States 

Funk 1973). However, walnut action tree small areas that would qualify as classica

improvement programs now exist and it seems walnut sites and their seedling production 

that large-scale production of improved walnut usually lower than in the Central and Nor

seedlings will be a reality soon. Central States. Consequently, walnut tre

improvement efforts have a lower priority 

Most tree improvement programs have as the East and Northeast and they were not

their primary goal the production of faster included in this survey. Additional info

growing, pest resistant trees with better form tion was provided by USDA Forest Service,

for increased timber yield. Such improvement State and Private Forestry. 2

is accomplished by identifying and selecting

the best trees and propagating them in seed

orchards. Seed from such orchards are used to RESULTS

produce improved nursery stock for future

reforestation. From this standpoint the All ii States were involved with wal

ability of these improved trees to produce improvement, although the level of involv

nuts is critical. The essential concept of an varied from State to State. The least in

orchard involves using trees of known high sive level of involvement was represented 

genetic potential for seed production as cooperation in provenance/progeny testing

opposed to buying or collecting seed from per- while the highest level involved actual 

haps Unseen and certainly untested trees, design and progeny testing with plans for

creating second generation orchards. Mos

programs may be described as basic improv

IResearch Geneticist, North Central Forest programs (Wright 1966).

Experiment Station, Forestry Sciences Laboratory, Carbondale, Illinois, and Forest Geneticist, Division of Forestry, Missouri Depart- 2Verbal communication, Mr. Clyde M. 

ment of Conservation, Licking, Missouri. Broomall, PA, June 1981.

• 
.

Most responses to the questionnaire indi- By contrast, the seedling seed orchard

cated high priority for walnut improvement and approach is one selected by Iowa, Wisconsin,

five States ranked walnut as the number one Minnesota, and USDA Forest Service. By this

priority species (table i). Many respondents approach, single tree nut collections are used

also indicated that their long-term goal was to create progeny tests. Mother trees from

to have all State nursery production of walnut which nuts are collected for progeny tests are

from improved seed. not rigorously selected; usually they are stlp-

. ulated to be only of average or better quality.

Responses reflect two basically different Rigorous selection at this stage is avoided

approaches to seed orchards--clonal vs. seed- because it is felt that there is no way to 

llng. In a clonal walnut orchard, selected evaluate single trees for important traits withtrees are propagated by grafting while seedling out even-aged neighbor trees growing on a slmlseed orchards are created by planting seed of lar site under similar conditions. In this

select trees and subsequently thinning the approach rigorous selection is carried out at

resulting stand to retain only the best pheno- the progeny test stage.

types for seed production.

Actually, the differences between the two

In many cases, there is a fundamental approaches are not clearcut because selected

philosophical difference between the two trees are usually progeny tested in the clonal

approaches. The clonal approachusually relies approach, too. Final selection for seed orchard

upon thebellef that a certain amount of gain inclusion is usually withheld until progeny test

can be achieved by selecting superior trees in results.

the Wild and vegetatively propagating such

trees. For example, Indiana, Kansas, and The two States with the most advanced walKentucky rely upon selecting trees on the basis nut improvement programs are Indiana and Missouri.

of growth rate, straightness, branch angle, Both States expect to be producing improved seed

bole quality, and apical dominance; trees are from their first generation orchards by 1985 and

selected and cloned if they are above average both list black walnut as their first priority

tosuperior in all or most of these traits, species.

This approach is most common with tree species

growing in even-aged stands. Selection is on The Indiana program is the oldest Statethe basis of comparison of these traits with operated walnut improvement program. It is a

neighboring trees. However, due to the coordinated effort between the Indiana Departscattered distribution of walnut and its habit ment of Natural Resources and Purdue University.

I This program has placed more emphasis on selecof growing in uneven-aged stands, such comparison tree selection schemes may not be reliable tion of wild trees than in any other State.

or efficient. As a result, selectioD of walnut Selections have been propagated in a clone bank

inthe wild is usually empirical, with no and approximately 100 of 250 origlnal selectlons

formal grading system, are being progeny tested. Based on performance

Table 1.--Summary of responses from informal survey mailed to ii States

Seedling Anticipated Current

seed No. Clonal No. Progeny date of seedling

_ b State orchard I families orchard I clones test orch. prod. prod. target Priority

• " (Acres) (Acres) (Acres)

I Illinois 30 60+ 1990 500,000 i

. Iowa I0 130 i0 1995 700,000 1

! • . Indiana.. 40 35 Ii 1985 300,000 1 Kansas . 37 85 2 1987 125,000 1 !

Kentucky i0 9 2000 300,000 #I hardwood

Michigan 18 i00,000 high

Minnesota 7 150 7 1990 300,000 2

Missouri 7.3 144 I0 73 1985 500,000 1

Ohio 0 ' 0 15 250,000 low

Tennessee 0 high

Wisconsin 7 150 0 7 1988 300,000 #i hardwood

#5 overall

iActual acres presently in orchard or in the midst of establishment.

58
°

in the clone bank and progeny test, 35 of these Both Michigan and Ohio are involved 

have been propagated in seed orchards. Second cooperative USDA Forest Service provenance/

generation orchards are being planned from progeny tests. Michigan has no plans for 

selections to be made from progeny test results, nut seed orchards, while Ohio already has 

• acres of progeny tests in various parts of 

The Missouri Department of Conservation State to be converted to seed orchards. 

program consists of 73 acres of Statewide of these Ohio tests were established in 19

progeny tests to be converted to seedling seed and should be producing seed soon if they 

orchards by roguing the poorest individual properly managed. Unfortunately, the Stat

trees and families. When the progeny testing no overall tree improvement program so the

iscomplete, superior genotypes will be com- progeny tests may be neglected.

bined into a clonal orchard.

The USDA Forest Service has identified

Both Indiana and Missouri plan to maintain black walnut as a first priority species 

original selections in clone banks, tree improvement in the Central States. W

improvement in the USDA Forest Service is 

In Kansas, responsibility for walnut marily the responsibility of the North Cen

improvement rests with the Department of Forest Experiment Station and the National

Forestry, Kansas State University. 'Although Forests in the Central States. Progeny te

their seedling requirements are modest, the have been established on the Shawnee, Wayn

program is well underway with two established Hoosier, and Monongahela National Forests 

clonal orchards. The lllinols Department of the 1973-1976 period with the objective of 

Conservation and Natural Heritage is also in version to seed orchards for National Fore

the midst of establishing two clonal orchards, walnut regeneration. Trees being progeny 

These orchards will consist of selections from are of average or better quality from seed 

existing USDA Forest Service and Indiana Depart- delineated for each National Forest; a min

ment of Natural Resources progeny tests, of 50 trees are included in each progeny 

• In addition, the North Central Forest Expe

The Iowa program is administered by the Station has established two progeny tests 

Iowa Conservation Commission. The program conversion to seed orchards for the State 

consists of two 5-acre progeny tests of 130 Illinois. These tests include 87 families

plus-trees selected throughout the State. The These progeny tests will probably be produ

progeny tests were established in 1976 and are improved seed by 1990.

intended to serve as seedling seed orchards

after roguing. These areas may have to be

expanded by grafting to meet seedling produc- THE OUTLOOK FOR THE FUTURE

tion needs.

In 1966 Funk described an idealized h

Both Kentucky and Tennessee walnut improve- thetical black walnut seed orchard. Accor

ment programs are in the early stages of estab- to Funk's (1966) calculations, an orchard 

lishment. The Kentucky Division of Forestry 20-foot square spacing should be able to p

has established 17 acres of regional and State- duce 30,000 seeds per acre in the "on" yea

wide provenance tests that will serve as an assuming an 80 percent seedling percent th

interim seed source until a clonal orchard is would translate t9 24,000 seedlings per or

established. Selection of superior phenotypes acre in good years. This means that a 10-

for the clonal orchard has already been orchard should average approximately 250,0

initiated. The Tennessee Division of Forestry seedlings at least every other year. Usin

expects to begin walnut seedling production in these figures as a crude, conservative gui

1982 and within 5 to i0 years anticipates pro- line, it is clear that most States that ll

ductlon in excess of a half million seedlings walnut as their first priority species alr

per year. An orchard is being planned from have orchard acreage that may meet their s

expansion of a clone bank contalningSO plus- llng needs upon maturity (assuming a 20-fo

tree selections as well as incorporation of square spacing, which is probably too clos

66 selections in a Tennessee Valley Authority The one exception to this is Iowa, which h

clone bank. Progeny testing will accompany the highest seedling requirement but only 

seed orchard construction, acres of orchard. Iowa's orchard acreage

should be at least 3 to 4 times greater if 

The walnut improvement programs of the seedling production is to be from improved 

Minnesota and Wisconsin Departments of Natural

Resources are similar. Both call for 7-acre One source of concern is the fact tha

progeny tests to be converted to seedling seed apparently many selections are not being a

orchards. Walnut is a second priority species quate!y progeny tested. Acreage listed in

in both States. table i for progeny tests seems rather low

.

. 

m •
considering how many selections have been made

and the number of orchards being established.

Without good progeny tests, it will be difficult to demonstrate potential gains by using

improved growing stock,

..

Nevertheless, improved walnut stock will

be a reality in the near future. Once it is

shown that improved walnut seedllngs are pest

resistant and have better form as well as

providing higher survival and growth, demand

for seedllngs will llkely increase dramatically.

Conservative projections indlcate possible

growth gains of from 15 to 30 percent over

current nursery stock by using first generatlon selections. Anadded improvement of that

magnitude should be possible in subsequent

generations.

..

LITERATURE CITED

Bey, Calvln F. 1973. Genetic variation and

selectlon, p. 62-65. In Black walnut as

a crop, Black Walnut Symposium, Carbondale,

7111nols, August 14-15, 1973. USDA For.

Serv. Gen. Tech. Rep. NC-4, 114 p., illus.

. North Cent: For. Exp. Stn., St. Paul, MN.

Funk, David T. 1966. Seed orchards, p. 62-

65. .... In. Black walnut culture. USDA For.

Serv., North Cent. For. Exp. Stn., St. Paul,

MN°

, Funk, David T. 1973. Genetics and tree

! improvement, p. 59-61. In Black walnut as

a crop, Black Walnut Sympos---lum,Carbondale,

i Illlnois, August 14-15, 1973. USDA For.

! Serv. Gen. Tech. Rep. NC-4, 114 p., illus.

North Cent. For. Exp. Stn., St. Paul, MN.

Wright, J. W. 1966. Breeding better timber

i varieties, p. 53-57. l__nBlack _n walnut

Culture. USDA For. Serv., North Cent. For.

Exp. Stn., St. Paul, MN.

i •

i '

|

t

t ,

! .

°

i_o
o

°

- INDIANA DIVISION OF FORESTRY BLACK WALNUT

1

TREE IMPROVEMENT PROGRAM

Mark V. Coggeshall and Stephen G, Pennlngton 2

Abstract _The State of Indiana black walnut tree improvement program is a cooperative effort between the Department of

°_ _ Forestry, Purdue University and the Indiana Department of

Natural Resources, Division of Forestry. The program steps

include phenotyplc Selectlon, clone bank evaluation of selectlons,

half-sibprogeny testing, and clonal seed orchard establishment.

......

The Indiana Division of Forestry initiated of all selections in the clone bank, half-

a'black walnut (Juglans rdgra L.) tree improve- progeny testing of the selectlons, and clo

ment program in 1971. TBe program can be charac- the best selections into state seed orchar

terlzed as a half_slb progeny test, ¢lonal seed This paper summarizes our efforts to date 

oteha_d approach. Aclone_Bank i_included. The each of these activities.

• goal of the program is to insure that black

walnut seedlings distributed by the two state

nurserleswill provide the best performance CURRENT STATUS

posslble when outplanted by Indiana landowners.

Specifically, there are four program objectives:

1) to preserve the highest quality specimens of Annual seed requirements for the two 

black walnut trees in Indiana by grafting their nurseries is approximately 750,000 walnuts

genotypes into the clone bank and state seed An average germination rate of 50 percent 

orchards_ 2Y to counteract the effects of a cull rate of 20 percent ylelds 300,000 

dysgenlc selectlon by re-lntroduclng the llngs annually. Seed is presently collect

offspring of these superior genotypes into by nursery personnel and other Division o

Indiana woodlands through seedling distribution Forestry properties with llttle regard fo

from the state nurseries; 3) to develop tree parent tree quality, especially in poor s

varieties that exhibit a high genetic potential years.

for. such characteristics as growth rate, form,

and disease resistance; and 4) to provide a The Indiana black walnut tree improve

continuous supply of seed from this improved program will supply hlgh quality seed to 

• stock for the state nurseries, state nurseries by insuring that superior

genotypes are the seed sources for the nu

The following steps are included in the in the future. The rationale for using t

Indiana black walnut tree improvement program: half-slb, clonal seed orchard approach wi

selection of superior phenotypes, establishment clone bank is addressed by Masters and Be

(1972). Each of the steps in the black w

' tree improvement program are addressed be

Ipaper presented at the 1981 Joint Meeting

of the Walnut Council/Northern Nut Growers SELECTION OF SUPERIOR PHENOTYPES

Association, West.Lafayette, Indiana, August

9-14 1981.

• '2The authors are respectively, Tree Approximately 250 superior phenotypes 

Improvement Specialist, Vallonla State Nursery, been selected from the natural black waln

• Vallonla, IN 47281 and Reforestation Supervisor, population in Indiana. Most of these tree

Indiana Division of Forestry, Indianapolis, IN graded on a point system for such characte

46204. as growth rate, aplcal dominance, straigh

. 
_I ° "

and habitat (W.F. Beineke, personal communica- p=ogeny test plantations representing 67

tion). However, environment can influence selections have been established at 12 sites

these traits and some superior phenotypes have since 1969 by Purdue University and the Indiana

been found to be genetically inferior when Division of Forestry.

progeny tested. As a result, comparison tree

selection _n plantations has lately received

more emphasis The majority of the newer

selections now included in the program are from

plantations or open-grown locations. New

selectlonshave also been made in older half-sib

progeny tests established by Purdue University

and the Indiana Division of Forestry. To date

13 recurrent selections are included in the

program.

,

' PURDUE CLONE BANK

Selections that have been accepted into the

program are grafted and placed in the clone bank

at the Purdue University Martell Forest. The

purpose of this clone bank is fourfold: I) to

gain an insight into a selection's performance

in future seed orchard situations (le growth

rate, flower production); 2) to evaluate the

ease bywhich a selection can be grafted; 3) to

_provide a source of easily obtained scion wood

'for use in the production of grafted trees for

the State seed orchards; and 4) to preserve the 

genotypes of the best quality specimens of black

in Indiana. The clone bank is maintained by

Purdue University.

Purdue University has been conducting black

i walnut genetics research, especially _nthe

areas of selection, flowering, and progeny

s testlng, since 1968. The results of this

!

i research has led to the incorporation of tested c!onal material into state seed orchards. The

i Indiana Division of Forestry is fortunate to

have this cooperative arrangement with Purdue

UniVersity whereby intensive research efforts

will result in direct benefits to the Indiana Figure I.-- @= Locations of half-sib progeny

landowner, test plantations in Indiana established by

" Purdue University and the Indiana Division of

' Forestry. X= Locations of state seed orchards.

HALF-SIB PRO@ENY TESTING

Since 1979 progeny tests have been planted

Yhe purpose of a half-sib progeny test at a Spacing of 4 X 4 feet (Coggeshall and

(.male parent unknown_ is to evaluate the Beineke, 1979). These close-spaced, short term

selections based on the performance of their progeny tests were established to evaluate

seedling offspring. Progeny testing provides Juvenile height growth. Kung (1973) used stem

information on the genetic value of the selec- analysis from 30 year old black walnut trees to

tions. Inadditlon, recurrent selectlonscan produce Juvenile-mature correlations. He found

be made in older progeny test plantations, that the correlation between Juvenile height

and cubic foot volume at 30 years reached a

Seed collected from the selections (both plateau at age 3. In addition, McKeand (1978)

orlg_nal parent trees and older clone Bank reported that family rankings for height growth

indivfduals_ are sown at the Vallonla Nursery in previous Indiana progeny tests stabilized by

and outplanted aa 1-0 stock at various locations age 4. The tallest families at age 4 were also

throughout Indiana (_ig. I). A total of 19 the tallest at age 9. Therefore, short term

62
progeny testing is valid for black walnut. Kung, F.H. 1973. Development and use 

Rapid screening of families is essential because juvenile-mature correlations in a b

black walnut produces highly variable seed-crops walnut tree improvement program. P

and new selectionsare constantly being added South. For. Tree Improv. Conf. p. 2

to the program maklng annual progeny test Masters, C.J., and W.F. Beineke.1972. 

establishment necessary. Good black walnut vs. half-sib seedling orchards for 

sites at both state nurseries and at the Purdue walnut. Proc. 20th NE For. Tree Im

• University Martell Forest have been designated Conf. p. 52-61.

as progeny test areas. McKeand, S.E. 1978. Analysis of half-s

progeny tests of black walnut. Unpu

There are several advantages to short term thesis. Purdue University. West Lafa

progeny testing. Less site variation will be Indiana.

encountered by planting at such close spacing

and weed control problems common to standard

progeny testing will be reduced. Also landowner interest will be intensified when planting

fast growing planting stock is made available

from the state nurseries.

CLONAL SEED ORCHARDS

A seed orchard is a collection of selected

trees established and grown together under

intensive management for mass production of

genetically improved seed. Cloning achieves

the result of bringing intensively selected,

but widely scattered trees to a common location

in their original genotypes. Higher genetic

gains can be realized by using this approach

(Masters and Beineke, 1972). Each selection

is replicated several times in the seed orchard

and arranged soas to maximize outcrossing.

Selections are grafted into the seed orchards

based on progeny test results and the performance

of grafts in the clone bank- form, foliation

dates, and fecundity. Many excellent clones

are not included in the orchards because of

poor nut production.

Thirty-four acres of clonal seed orchards

have been established in 3 locations throughout

the state (fig. I). Seed orchard establishment

began in 1970. Approximately 30 to 40 clones

have been selected from the 250 original

selections to be included in the seed orchards

and20 to 25 clones are being propagated

annually at Vallonia.

LITERATURE CITED

Coggeshall, M.V., and W.F. Beineke. 1979. Short

term progeny tests for black walnut and tulip

popla r. U.S.D.A. For. Serv. State & Private

Forestry. NE Nurseryman Conf. Bloomington,

Indiana. p. 79-81. "

|

!
.

NEW DIRECTIONS IN GENETIC IMPROVEMENT:

.

GRAFTED BLACK W_T PLANTATIONS 1

Walter F. Beineke 2

Abstract.--Black walnut produces fewer seed per tree than

most tree species which leads to problems of providing

sufficient seed from traditional seed orchard production of

, genetically superior planting stock. Seedlings seldom capture

the full complement of genetic improvement possible from

parent trees particularly when the male parent is unknown or

inferior.

" Vegetatively propagated plantations provide a method to

take advantage of the complete potential improvement of an

improved selection. Patenting and licensing provide protection

for researchers who have invested time and money in developing

and proving superiority.

Gains in height, diameter, and form are discussed as well

. as risks from monoculture and containerized planting.

....

.

INTRODUCTION The number of nuts produced per tree can

be increased by selecting good nut producers,

Authors of past Walnut Symposium articles wide spacing, fertilization, and weed control,

on tree improvement have predicted promising but walnut still requires many years to

results from the genetic manipulation of black produce quantities of seed and never approaches

! walnut (Bey 1973, Brunk 1973, Funk 1966, the prolific seed production of the lightFunk 1973, and Wright 1966). Geneticists have seeded species. Thus, seed orchard programs

e

cut years from the projected time needed to for black walnut must provide for this lack of

produce improved stock, but we are still i0 seed production with increased seed orchard

i to 15 years from producing significant volumes acreage and improved management.

• oflmproved black walnut seed.

Improving trees through genetics is long- SEEDLING VS. CLONAL PROPAGATION

. term and black walnut poses some particularly

, vexing problems (Beineke 1979). Walnut, Seedlings are the product of pollination

unlike plnes, "cottonwood, sycamore, sweet gum, and fertillzatlon, a sexual process, and are

and many other species, is not a prolific seed genetically different, just as brothers and

producer. While a pine tree can produce many sisters differ, even though they have the same

thousands of seed each year, most walnut trees parents. Of course, siblings usually do have

' ' produce, at best, only several hundred seed, some resemblance to their parents and to each

and pests can claim a large share of those, other, but they are variable. That portion

From the remaining seed, nurserymen routinely of variation is one source of inherited

obtain only 50 to 60 percent germination, improvement--the additive portion. That

is the only portion that can be depended

• . on to provide improvement when sexual reproduction is used.

Ipaper presented at the Walnut CouncilNNGA Black Walnut Symposium, Purdue University, On the other hand when grafting or other

West Lafayette, IN. August 9-14, 1981. means of vegetative reproduction is used, all

2Associate Professor of Forestry, Dept. of the genetic potential (non-addltive plus

of Forestry and Natural Resources, Purdue the additive portion) of the superior tree

University , West Lafayette, IN. 47907. can be passed on to the next generation

(Libby 1977). That is, a graft is an exact

64
genetic duplicate (clone) of the selected Genetic uniformity in tree size, for

tree containing all of the improvement nut production and wood properties is a

possible from the aboveground portion of the positive factor in favor of clonal propaga

parent. For some traits such as volume growth, tion. Economic advantages accrue in the

having low additive inheritance, Zobel (1981), marketing and harvesting of uniform stand

states that, "it appears possible tO more than (Zobel 1981).

double short-term genetic gain by using

vegetative propagules rather than seed regen- At the present time, the only operat

eratlon." practical vegetative propagation technique

for black walnut is by grafting (Belneke 

Once a superior tree is identified and Todhunter, 1980). However, two other met

tested for a sufficient time, it can be may show promise in the future - rooted

multiplied by vegetative propagation at a cuttings and tissue culture.

fairly young age without waiting for seed

production to occur. In the first 12 years Rooting of cuttings is a commonly us

"it is estimated that nearly i0 times more method to propagate many plant species.

plants can be reproduced from a young walnut Major advantages of rooted cuttings are 

by grafting than from seed (table i). the plant is supported by its own genetic

, compatible root system and is cheaper tha

grafting. With few exceptions, (Carpenter

1975, Farmer 1971, Shreve and Miles 1972)

rooting of black walnut cuttings has prov

Table l.--Estimates of average numbers of to be extremely difficult. Cuttings requ

propagules available from walnut clones at a length of stem, usually with a terminal

various ages. meristem intact, thus greatly reducing th

number of propagules obtained from a tree

compared with grafting. In black walnut 

Numbers of same length of stem used for one cutting

Tree •age/ Numbers of grafting buds could produce three or four grafts.

year seed produced produced

Tissue culture, a fairly new tool, i

i 0 0 emerging as a revolutionary vegetative pr

2 0 5 gation technique for many species (Murash

3 0 15 1974, Durzan and Campbell 1974). Briefly

4 3 50 tissue culture in black walnut would prob

5 7 i00 involve removal of a vegetative bud from 

6 i0 • 200 Superior tree and placement on a sterile 

7 15 350 ing media in a petri dish. Subsequent bu

8 30 500 growth and shoot elongation would produce

9 60 650 lateral bud formation along the shoot. 

10 110 800 of these lateral buds would then be excis

ii 130 1000 and placed on media to grow and multiply

12 150 1300 proliferating a single bud into hundreds 

Total 515 4970 thousands of plantlets. Shoots for opera

Average 43 414 planting would have to be placed on speci

rooting media to induce root formation a

• growth. Plantlets would then be transfer

to containers and moved to the greenhouse 

hence to the field.

Each step in this process has an in

Also, nut production in black walnut tends ble array of problems to be solved and, 

tobe cyclic with most trees producing large present, is strictly theoretical. Howeve

Crops only once in 2 to 4 years, and the crop has been accomplished for roses, apples,

may be subject to frost and insect damage loblolly pine, and a few other woody spec

(Hasegawa 1979, Huth 1978, Mort and Amers

every year. That is why average yearly nut

productlon does not rise sharply after the 1981). The advantages of this technique 

of course, the unlimited number and rapid

first few years (table i). In contrast, new

propagation of an improved cultlvar from 

branches having graftable buds grow every buds. Once techniques became operational

year. Even following years of slow growth, tissue culture would probably be cheaper 

large amounts of grafting wood are available; grafting (McKeand 1981)

especially from trees pruned vigorously and

annually.

• 
°

PATENTING while the clonal test is at Martell Forest

near West Lafayette, in central Indiana.

The use of vegetative propagation provides Therefore, differing soils and climatic

an opportunity to patent improved clones, factors apply. The southern Indiana seedling

Plant patents grant protection from indiscrlm- test is on a marginal walnut soil while the

inant propagation of improved material. The Martell soil is a fair to good walnut soil.

rationale behind patenting is that the devel- Both sites have had fair to good weed control,

oper who took the risks and funded the work annual pruning, and occasional fertilizer

should have the opportunity to profit without appllcations of Urea or 12-12-12.

competition from those who did not have the

foresight to provide funding for the development of the new material. To obtain a plant

patent, the "unique" attributes of the plant

must be proven. Note that "genetic improve- Table 2.--Growth and form characteristics of

ment" is not necessarily a criteria for patented Purdue 1 grafts vs. checks compared

patent_ing. Proving a tree unique is a time- with Purdue 1 seedlings vs. checks.

_consuming, difficult and expensive process

which involves comparisons of traits with,

known or previously patented material of the Height DBH Volume Stem

same species. (ft.) (in.) (cu. ft.) Form I'

Patenting black walnut for timber purposes 9 years old -

had never been previously attempted until the Purdue 1 grafts 26.6 4.9 1.77 1.3

patents on Purdue 1, 2, and 3 were issued. Seedling checks 20.3 3.8 .92 3.3

After the patent is granted, the patented tree Percent gain 31 29 92 61

can be licensed for propagation and sale to

the public. Purdue i, 2, and 3 were patented ii years oldby and licensed for propagation through the Purdue i seedPurdue Research Foundation. This arrangement lings 23.9 4.4 1.36 2.7

allows the University to collect royalties Seedling checks 21.5 3.7 .92 3.3

On the sale of each tree, thus obtaining some Percent gain ii 19 48 18

return on its investment in research.

i/Rating Scale: 1 = excellent form to

The grafted clone approach differs 5 = very poor form.

greatly from the seed orchard approach outlined in previous papers at this symposium.

! The use of buds rather than seed is the basis

1 of propagation and involves several additional

! items- i.e., budwood collection, storage,

and care. Seedling production requires

only the standard nursery installation. Seedlings vs. the check do not show the

Grafted black walnut requires much more invest- percent gain of grafts vs. the check (table 2).

ment in production facilities such as green- This is an expression of several factors, inhouse, propagation areas, potting equipment, cluding the graft's ability to exploit the

•_ grafting materials, budwood storage, holding full complement of inherited superiority as

I areas for completed grafts, and skilled was discussed earlier. Another factor of

technicians to do the grafting in addition to great importance is that the seed collected

! the standard nursery to produce rootstocks from the superior tree in the natural setting

for grafting, includes an unknown male pollinator or

I several unknown pollinator components. They

i may have passed on superior genes or inferior

' GENETIC GAINS genes for growth, etc. Therefore, the

seedling mix contains a genetic component that

How much gain can be expected using is unknown and in all likllhood detrimental.

vegetative propagation rather than seedling

reproduction? Unfortunately, large, well- Form improvement is perhaps most indicadesigned, older tests are not available to rive of the value of using clones. Stem

study this crucial aspect. However, from our form was obtained by subjectively rating the

older° tests containing seedlings from patented straightness of the main stem on a scale of i

Purdue I vs. a nursery-run check and grafted to 5 with i representing a perfectly straight

patented Purdue i vs. a nursery check, some stem, 2 - slight crook or deviation of the

rough estimates can be made (table 2). The central stem, 3 - about average straightness,

seedling test is located in southern Indiana, 4 - several severe crooks or a single fork,

66
°

and5 - a very crooked, forked and/or leaning clones and seedlings are from scattered

central stem. In table 2, form improvement geographic areas, while natural stands 

from seedling progeny is good, but improvement from local, often isolated, and related

from clonal material is truly outstanding. It individuals (Belneke 1972).

is significant to note that the check trees in

both plantings had identical poorer than Unique, often unexpected problems

average stem forms, even though the two plant- accompany any new endeavor and plantatio

ings are located 150 miles apart, of grafts rather than seedlings have th

share. Most plantings of grafts have b

made with containerized milk carton stoc

RISKS The graft is usually only a few months 

The cartons are bulky and difficult to 

The alleged problems associated with the port and plant. Also, root systems are

planting of the same genotypes over large reluctant to grow from the optimum rooti

acreages, is often mentioned as a reason for media of the container into the soll of 

not using clones (Zobel 1981). Monoculture real world. Death or dleback of the gr

: invokes the specter of catastrophic 'losses to often results during the winter months 

some unknown disease, insect or climatic outplantlng. Unlike seedling dieback, 

happening. Dutch elm disease and,chestnut seldom results in any significant losses

blight are often used as examples. If a graft dieback and resprouting of the ro

disease of this magnitude invades walnut, it systemmeans that the expensive and pamp

will destroy them all whether they are of graft has become a common seedling. Th

seedllng or clonal origin. Monoculture was occurs if the graft is damaged by animal

not the reason Dutch elm disease or chestnut predation, weed control tools, or wind. 

blight spread so rapidly. Walnut is a native dieback can be reduced by holding grafts 

species well-adapted to the climate, diseases, winter, and outplanting them as dormant 

and insects of the eastern U.S. Care must be root grafts the following spring. This

taken to select only those clones that show technique allows grafts to be handled a

• some resistance or are not overly susceptible planted in the same manner as seedlings. 

to the pests that affect black walnut. Of control, pruning, fertilization and oth

course, there is risk involved in using only cultural treatments are the same for gr

a few clones but this must be balanced against plantations or seedling plantations.

potential gains in time, tree form, and nut

production.

CONCLUSIONS

Black walnut growers are not the first

long-term-tree crop orchardists to contemplate Black walnut tree improvement has 

growing a few varieties over rather large that rapid increases in growth and form 

acreage. For instance, fruit orchards usually be made and in a few years grafts and s

contain a very limlted number of clones lings from improved trees will be avalla

(cultivars) that are usually not native to the in sufficient quantities to begin to me

area. The crop is long-term and there are demand.

few reports of catastrophic tree loss due to

• monoculture. A possible exception may be Seed orchards for genetically impr

climatic losses due to varieties being planted seedling production will still provide 

outside of their hardiness zones. Fifty-year- of the black walnut seed required for r

• old grafted pecan orchards are a closer eratlon purposes far Into the future. 

comparison with black walnut and I'm sure that outlined in previous papers at this sym

many NNGA members could point to similar demand for walnut seedling stock is sta

examples of a few nut tree varieties planted Due to the investment required and the

' in rather large blocks. In fact thousands of unpredictability of propagation success,

grafted Thomas black walnut trees have been numbers of grafted trees wlll always be

planted in large blocks during the past 50 limited. Therefore, clonal propagation 

years with no reports of catastrophic disease probably remain a rather small percentag

or insect losses, total production. Grafted stock will b

available for those growers who desire 

Even so, single clone monocultures are maximum genetic improvement possible no

not recommended and mixtures of several clones are willing to pay the high cost.

and/or seedlings should be planted. Such

mixes are probably more diverse genetically Despite cutbacks in research dollar

than most natural walnut stands when you scientists involved In the genetic impr

consider that the various genetically improved of black walnut, prospects for future i

ment appear optimistic. We have Just b
o

to tap the tremendous genetic variation in McKeand, S. E. 1981• Loblolly pine tissue

growth, form, and nut-bearing capabilities in culture: present and future uses in

black walnut. New selections are presently southern forestry. School of For. Resources.

under test that may prove to be far superior N.C. State Univ. Tech. Rpt. No. 64. 50 p.

to anything now available. Studies have Mort, R. L. and H. V. Amerson. 1981. A

I indicated methods that may allow us to select tissue culture process for the clonal

• for superior growth rate at very early ages, production of loblolly pine plantlets.

, perhaps one year, making it possible to avoid North Carolina Agrlc. Res. Serv. Tech.

I some of the long-term testing presently Bul. No. 271. 14 p.

necessary. Selection, breeding and testing Murashlge, T. 1974 Plant propagation

: walnut for superiority must be a continuing through tissue culture. Ann. Rev. Plant

process. Grafted plantations will prove to Physiol. 25:135-166.

-- be a tool that will allow the landowner to Shreve, L. W. and N. W. Miles. 1972. Propatake full advantage of rapid improvement, gating black walnut clones from rooted

cuttings. Plant Propagator 18:4-7.

Wright, J. W. 1966. Breeding better timber

, LITERATURE CITED varieties. I__nnBlack Walnut Culture.

USDA For. Serv•, Carbondale, Ii• p. 53-57.

Beineke, W. F. 1979. Tree improvement in , Zobel, B. J. 1981. Vegetative propagation

the oaks. I__n.n Wright Forestry Conference in forest management operations. 16th

i Proceedings. Purdue Univ., W. Lafayette, Southern For. Tree Impr. Conf., Blacksburg,

In p. 126-132 Va (In press)

Beineke, W. F. 1972. Recent changes in the

:: population structure of black walnut. 8th

Central States Tree Impr. Conf., Columbia,

• Mo. p. 43-46.

i Beineke, W. F. and M. N. Todhunter. 1980.

! Grafting black walnut. Purdue Univ. Agric. 

• Exp. Sta. Bulletin FNR-105. 3 p.

't Bey, C. F. 1973. Genetic variation and

selection. In Black Walnut as a Crop.

• USDA For. Serv. Gen. Tech. Rpt. NC-4.

p; 62-65.

Brunk, E. L. 1973. Tree improvement action

. programs- the Missouri story. I_n.nBlack

Walnut as a Crop. USDA For. Serv. Gen.

Tech. Rpt. NC-4. p. 71-74.

Carpenter, S. B. 1975. Rooting black walnut

cuttings with Ethephon. Tree Planters

Notes 26:3,29.

Durzan, D. J. and R. A. Campbell. 1974.

Prospects for the mass production of

improved stock of forest trees by cell and

tissue culture. Can. J. For. Res.

4:151-174.

• Farmer, R. E., Jr. 1971. Rooting black walnut Cuttings. Plant Propagator 17:7-8.

Funk, D. T. 1966. Seed orchards, l__nnBlack

Walnut Culture. USDA For. Serv., Carbondale, Ii. p. 62-65.

Funk, D. T. 1973. Genetics and tree improvement. In Black Walnut as a Crop. USDA

For. Ser--v.Gen. Tech. Zpt. NC-4. p. 59-61.

Hasegawa, P.M. 1979. In vitro propagation

of rose. Hort. Sci. 14:610-612.

Huth, W. 1978. (Culture of apple plants

from apical merlstems) (Get.) Gartenbauwissenschaft 43:163-166.

Libby, W. J. 1977. Rooted cuttings in

production forests. 14th Southern For.

Tree Impr. Conf., Gainesville, FI. p. 13-19.

68
.

SOME GUIDELINES FOR SELECTING BLACK WALNUT PLANTING SITES

Felix Ponder, Jr. 1

Abstract.--Black walnut grows best on fertile, deep,

well-drained soils. Sites most often considered for growing

walnut are abandoned farms that have never supported walnut.

Therefore, soil information taken from other walnut sites

must be used to evaluate the suitability of new areas for

walnut.

Growing a crop of high-value walnut determining site quality. A mottled zone 

(Juglans nigra L.) trees is a long-term project layer that has spots or blotches of differe

that requires investments of land, time, and colors or shades of colors; it is usually

money. One of the black walnut grower's most associated with water saturation. Losche

important decisions is where to grow this (1973) concluded that an easily recognized 

valuable timber- and nut-producing hardwood, characteristic "depth to gravel layer" can 

Successful walnut plantations are rare, mainly used to rate the suitability of some floodbecause many were establlshed on unsultable plaln soils for black walnut. More recentl

soils. But from successful plantatlons on Geyer and others (1980) Showed that site

. suitable soils and from a few naturally estab- quality for black walnut was closely relate

lished stands, we have learned much about where to soll and topographic characteristics. 

.. to plant black walnut. Frankly, a lot of what found, in addition to those factors describ

we know came from failures, also. by Auten and Losche, that soil origin, surf

soll thickness, aspect, and water holding

Broadly speaking, soil variables such as capacity were also important. These factor

origin, physical condition, available water will be discussed here in detail.

during the growing season, aeration, and

• nutrient availability determine how productive

a site will be for black walnut or for any LANDFORM 

other vegetation. Losche and others (1972)

developed a guide for selecting black walnut Site position and slope aspect are ve

sites using these variables. As a result of important in site selection. Walnut grows

their work, soils in Illlnols were classifled best on deep, loose, alluvial soils, free 

as suited, questionable, and unsuited for mottling. Carmean (1966) reported that on

black walnut. However, the guide has been Sharonsilt loam, a 25-year-old plantatlon 

only partially successful, malnly because our dominant trees 84 feet tall. Such exceptio

knowledge is still too meager to measure growth exceeds all previously known growth

accurately what determines the success of a records for black walnut.

walnut plantation. But the few variables we

do know that contribute to good walnut growth Such bottomland sites are usually fla

have consistently shown to be reliable in except for depressions of a few inches or, 

' determining plantation success, most, a foot or two. Little depressions o

, indicate a tight, shallow soil that restric

Most soil site studies indicate that no water absorption. But this condition may 

single factor alone makes a site good, but corrected by deep tillage and/or subsoiling

that a combination of factors are involved.

On the other hand, one single factor might make Slope position and steepness as well 

a site unsatisfactory for black walnut. Auten total soil depth often relate closely to s

(1945)found that soil drainage, depth to face soil thickness (Geyer and others 1980

mottling, and texture were the m_Jor factors Smooth and gently rolling landscapes genera

present no critical problem. More importan

these sites are soll characteristics sucha

iResearch Soll Scientist, North Central texture and internal drainage. Shallow, h

Forest Experiment Station, Forestry Sciences textured, imperfectly drained upland soils 

Laboratory, Carbondale, Illinols. not suitable for walnut.

• 
i

°

• The better planting areas on rolling and DRAINAGE

mountainous landscapes are usually located on

the lower north- and east-faclng slopes, Walnut usually does not grow satisfactorily

stream terraces, and flood plains. These areas on poorly drained soils but it can tolerate

usually have the soil moisture and soil thick- occasional flooding of short duration. The

ness required for satisfactory walnut growth, site should be examined for evidence of

i Steep, South-facing slopes and narrow ridge restricted internal drainage which may affect

tops would generally be poor walnut sites, surface drainage. Restrictive internal drainSuch _Sites are often dry and because of their age causes poor aeration, leading to inhibited

susceptibility to erosion are generally shallow, root growth and reduced tree height and diameter

i Depending on the geographic location, water growth. Good internal drainage provides favordeficiencies on south and southwest aspects able conditions for the development of extensive

• may be intensified by high daytime temperatures root systems and more complete use of moisture

• and strong winds throughout the growing season, and nutrients.

Onutri n soientlss,having organigood c matstoierl moi tendsstureto aaccumula nd morete To estimate internal drainage, the grower

because of the more favorable conditions. But must consider soll factors including texture,

on'dry and excessively drained soils, especi- compaction, and structure. Color seems to be 

ally on hot sites, organic matter is quickly a good correlator of internal soil drainage and

Oxidized. is the easiest to recognize. The color

(mottllng) of the subsoil is usually an indication of how much air (aeration) occupies the

SOIL DEPTH spaces between soll particles (table 1). Poor

drainage due to heavy subsoil or a high water

Black walnut tends to develop a large table is llkely to produce a blue or drab color

taproot which will penetrate 4 feet in 1 year because the oxides of iron remain in the ferrous

and more than 9 feet in 3 years in well-dralned, condition. If the soil has good internal drainmedium-textured soils. Because of walnut's age, the iron compounds are oxidized to red

• deep rooting habit, Auten (1945) proposed that ferric oxides and the soil becomes red, brown,

the surface soll in planting sites should be or yellowish-brown. Soils with evidence of

at least 16 inches thick and that soils having mottling within 2 feet of the surface should

thinner surface s0il should not be considered be avoided.

for walnut planting sites. However, I recommend

that the minimum soil depth in a prospective

site should not be less than 3 feet. Shallower Table l.--Estimation of internal drainage based

soils will not hold enough water to support on soil color I

i

i -satisfactory growth. Also, the grower must •

i

i realize that even the 3-foot depth could limit

growth and the final product to be harvested. Drainage Color Possible

An effective soil depth of 5 feet (without class (mottling) topography

restrictive layer) would better ensure good

walnu t growth. Very slow Drab and blue Swampy, high

below 8" water table

TEXTURE Slow Dull yellowish- Low areas

" ' " brown

i Soil texture influences the water holding below 14"

| capacity, available water, and the ease at

which roots are able to penetrate. Black walnut Fair Yellow Level upland

i generally prefers deep well-drained silt loam 14-24"

I , soils. SUitable topsoil textures also include

sandy loam and loam. The subsoll should have Moderate Brownish-yellow Rolling upland

the same texture as the topsoil or a sandy clay below 35"

10am or clay loam. Even though no consistent

relationshl p has been found between pH and Good-fast Yellowish-brown Terraces

growth, soils with acid, clayey subsoils should

be avoided. Good plantlng sites also include Good-very fast Red-brown Moraines or

limestone soils with silt loam over clayey sub- loose sand

soils and deep rocky soils unsuitable for

Cultivation because of their rocklness. Usually 1Auten (1945) and USDA Soil Survey Manual

walnut grows poorly on coarse-textured soils. (1962).

70
Both the gravel layer and mottling zone autumn-olive with walnut increased site ind

indicate soil conditions that inhibit deeper by an average of 14 feet, changing what was

root growth. Therefore, soils with coarse sand originally considered a marginal site into 

or gravel layers and bedrock within 3 feet of medium quality site for walnut. The effect 

the surface should be avoided, autumn-olive on growth was most dramatic on

poor sites. However, care must be taken t

prevent the spread of autumn-olive onto unw

OTHER FACTORS areas. Also encouraging are the early resu

from a forage legume study being done by

Black walnut growing on bottomland sedi- researchers at Carbondale. Hairy vetch, wh

ments benefits from the greater water avail- required 2 years for establishment, signifi

ability. Comparatively, upland soils, though increased seedling growth more than Korean

well drained, usually lack the depth and lespedeza, crimson clover, and Sericea lesp

organic matter which increase the amount of did after 2 years of growth. Both hairy ve

water a soll can hold. and Sericea lespedeza controlled weeds bett

than the other legumes did (Van Sambeek and

Wind affects the establishment of black Rietveld 1981). Thus, planting companion 

walnut. Seedlings planted in level, windswept, and forage legumes on walnut sites may prov

open fields are less vigorous, have smaller an alternative to chemical weed control and

leaf areas, and suffer more foliage damage fertilization.

than those planted in similar soils in either

forest openings or protected fields (Schneider Cultural practices designed to increas

and others 1970). available soil moisture might promote walnu

growth. These practices include irrigation

Vegetation on the site may indicate the terracing, mulching, and control of undesir

fertility and/or moisture condition of the moisture using vegetation. Practices desig

soil. A sparse cover of weeds and grasses to improve subsoil drainage and aeration mi

. generally indicates low fertility, erosion, include surface and tile drainage and, in

or droughty soil conditions; such sites should addition, deep tillage may promote better 

not be planted to walnut. In contrast, a ing in the subsoil.

vigorous ground cover suggests the site may

be suitable for planting walnut. Composition

of the cover is also important. For example, SUMMARY

Sedges indicate a wet soll that probably is

unsuitable for adequate walnut growth. To summarize, these are the major soil

conditions to avoid in locating black walnu

The soils of some old "fields may contain planting sites: 

toxic substances produced by other plants

which could inhibit the nutrient uptake and Problem Indicators

growth of black walnut seedlings (see Rietveld

paper presented at this symposium). Such toxic Poorly drained Compact subsoil; mottl

substances may also affect beneficial root- 8-14"; sedges

infecting fungi and microorganisms.

Excessively dry. Bedrock, coarse sand, 

site or gravel layer <36"

SITE IMPROVEMENT below the surface; co

pact subsoil; inadequ

Now comes the ultimate question: How can infiltration

walnut be grown successfully on a parcel of

land that lacks the proper drainage, depth, or Clay and silty Compact subsoil; inade

other characteristics of an ideal walnut site? clay infiltration

Several practices have been tried in an effort

to increase the productivity of marginal sites. Growers should look for sites having 

Most attempts such as fertilizing sites following soil properties:

believed depleted of nutrients and refilling

deep trenches and tile drainage in poorly Soil _roperties Indicators

drained soil have resulted in limited success.

An alternative to fertilization may be inter- Deep, well drained Bottomland; >5

planting with nitrogen-fixing plants such as red-brown colo

autumn-olive or European alder. These plants

can biologically fix atmospheric nitrogen which Limestone-derived soil

can later be released and used by other plants.

Several studies have shown that planting Yellow, brown, or reddish Without mottle

brown subsoils >3' deep -

• 

1

-s'
i Knowing the relative productivity of soils

in potential planting areas and existing walnut

stands will enable the walnut grower to locate

new plantations on the best available soils.

Growers are urged to use state foresters, soil

SurveY information, and research data in their

search for suitable black walnut planting sites.

LITERATURE CITED

Auten, John T. 1945. Some soll factors

associated with site quality for planted

black locust and black walnut. J. For. 43:

592-598.

Carmean, Willard H 1966 Soil and water

_requlrements. p. 32-34. l_n_nWalnutCulture

Workshop Proceedings. USDA For. Serv.,

North Cent. For. Exp. Stn., St. Paul, MN. '

Geyer, WaYne A., Robert D. Marquard, and Joel F.

Barber• 1980. Black walnut site quality in

relation to soil and topographic characteristics in northeastern Kansas. J. Soil and

Water Conserv. 35:135-137.

Losche, Craig K. 1973. Black walnut grows

best on deep, well-drained bottomland soils.

USDA For. Serv. Res. Note NC-154_ 3 p. North

Cent. FOr. Exp. Stn., St. Paul, MN.

._Losche, Craig K., William M. Clark, Earl E. Voss,

and Burl S. Ashley. 1972. Guide to the

selection of soil for growing black walnut

in Illinois. Spec. Pub., Northeast. Area

State and Private Forestry, Upper Derby, PA.

38 p.

i Schneider, G., Ghaus Khattak, and John N. Bright.

i 1970. Modifying sites for the establlshment

of black walnut, p. 155-169. l__nC. T. Youngi berg and Charles B. Davey, eds. Forest Soils

Conf., Raleigh, NC.

Soil Survey Staff. 1962. Soll color, p. 189-

203. In Soll survey manual• U.S, Dep. Agric.

' Agric.-_ndb. 18. U.S. Govt. Printing Office,

Washington, DC.

van Sambeek, J. W. and W. J. Rietveld. 1981•

Seedlng forage legumes in black walnut plantations. Walnut Council-Bull. 8:6-8.

°

72
THE SIGNIFICANCE OF ALLELOPATHY IN BLACK WALNUT CULTURAL SYSTEMS

W. J. Rietveld I

Abstract.--The importance of allelopathy in black walnut

cultural systems was evaluated. Laboratory tests showed that

18 species being considered for mixed plantings with walnut

were all sensitive to juglone. In mixed, even-aged plantations

containing walnut, there is a buildup period of approximately

12-15 years before allelopathic effects become noticeable, if

they Occur at all. This allows ample time for growing shortterm co-crops, nurse crops, and cover crops with walnut.

Walnut's phytotoxic activity may even be beneficial in effecting its own release. Long-term mixed walnut/pine plantings

are not recommended. The long-term allelopathic effects in

mixed walnut/hardwood plantings are uncertain, and may be

subtle. Potential allelopathic effects of plantation weeds on

growth of walnut seedlings and saplings are considered, along

with the need for vegetation management in plantations.

• Q

Through evolution, plant species have the reported occurrences of walnut allelop

developed an array of intricate adaptations (with the important exception of conifers)

to ensure survival and perpetuation. One of involves toxicity between existing large 

these schemes--called allelopathy2--involves nut trees and vegetables, field crops, fr

the production of chemical substances which, and ornamentals. However, a subject that 

when released into the environment, directly not yet been addressed directly in the li

• or indirectly harms selected neighboring ture is: What are the implications of wa

plants. Allelopathic chemicals may control allelopathy in forestry? As silviculturis

the sequence and rate of plant succession, we are more interested in knowing the sig

cause changes in species composition, and cance of allelopathy in forest and planta

alter plant productivity. Allelopathy should situations. This paper will explore the 

not be confused with physical competition, mented and suspected allelopathic relation

because allelopathy involves a chemical com- that may occur in walnut plantations, ass

pound being added to the environment, whereas their importance to walnut culture, and r

competition involves the removal or reduction mend silvicultural treatments to avoid or 

• of some growth factor (light, water, nutrients, come their effects.

space) required simultaneously or sequentially

by some other plant sharing the environment.

II II

The term interference refers to the overall HISTORY OF BLACK WALNUT ALLELOPATHY

deleterious effects of one plant on another,

encompassing both competition and allelopathy According to Gries (1943), the first

(Muller 1969). written record of walnut toxicity can be 

back to the first century A.D., when Plin

• Black walnut (Jug lens nigra L.) is the Elder, in his Naturalis Historia wrote: 

most notorious of allelopathic trees. However, shadow of walnut trees is poison to all p

that notoriety needs qualification. Most of within its compass, and it kills whatever 

touches ."

iPrincipal Plant Physiologist; North

Central Forest Experiment Station, Forestry Up to the present time, and especiall

Sciences Laboratory, Carbondale, Illinois. during the past 50 years, walnut has been

2Recent reviews on allelopathy include reported to be toxic to a wide variety of 

those by Sondheimer and Simeone (1970), isms including herbaceous and woody plant

National Academy of Sciences (1971), Whittaker (Brooks 1951), fungi (Hedin et al. 1979), 

and Feeney (1971), Rice (1974, 1979), Fisher organisms (KraJci and Lynch 1978), insect

(1976, 1979), Horsley (1976), and Rietveld (Gilbert et al. 1967), fish (Marking 1970

. (1979). mammals (Auyong et al. 1963). The princi
chemical responsible for walnut allelopathy contact the roots of walnut, while others may

has been identified as juglone (5-hydroxy-l,4- be capable of withstanding the strong oxidizing

nap hthoquinone) (Davis 1928), which is found power of juglone.

in the leaves, fruit hulls, inner bark, and

roots of walnut (Lee and Campbell 1969). Rain

washes it from living leaves and carries it PLANT ASSOCIATIONS INVOLVING

to the soil; it is released also, along with BLACK WALNUT AND ALLELOPATHY

tannins, from dead leaves and fruits to the

soil. Juglone has been isolated from many Four types of plant associations involving

plants in the walnut family, including black black walnut can be identified:

walnut, butternut (J. cinerea L.), Persian

walnut (J. regia L.), Siebold walnut (J. i. Natural forest stands containing

ailantifolia Carr.), Manchurian walnut (J. walnut as a component.

mandShurica Maxim. ), shagbark hickory (Carya

ovata (Mill.) K. Koch), mockernut hickory (C. 2. Various species planted within the

tomentosa _Nutt.), Caucasian walnut (Pterocarya influence zone of existing large

fraxinifolia (Lain.)Spach), and pecan (C. walnut trees. 

illinoensis (Wangenh.) K. Koch) (Thomson !971,'

Graves et al, 1979). 3. Sapling plantations containing an

even-aged mixture of walnut and

Not _all reports have supported the exist- one or more other woody species.

ence of walnut toxicity, for in many cases

species thought to be sensitive were observed 4. Walnut seedlings planted admidst

co-existingwith walnut. A controversy develop- herbaceous vegetation.

ed in which the key issue was whether root

contact was necessary for toxicity to occur. The first two types of plant associations

The divergent results were best explained by are listed for completeness, but they are not

Gries (1943) as follows: the subject of this paper and will be mentioned

only briefly.

"Juglone, as such, occurs prob- 

ably only in minute quantities in A comprehensive survey of the association

the inner root bark and in the green of native vegetation with black walnut trees

husks of the nuts. These regions, was published by Brooks in 1951. His extensive

are, however, rich in a substance tables list over 218 species growing within and

known as hydrojuglone. This com- outside the root and crown spreads of walnut

pound, the colorless, non-toxic trees. While some species (e.g., blackberry,

reduced form of juglone, is immedi- blueberry, heaths, pines) are rarely associated

ately oxidized to its toxic form with walnut, others (Kentucky bluegrass, black

upon exposure to the air or some raspberry) grow better within the root zone of

oxidizing substance from the roots walnut than outside. The potential roles of

Of other plants. Upon standing in allelopathy in differentiation, patterning, and

the air, juglone again disappears, composition of natural forest stands were disbeing either changed back to hydro- cussed in a previous paper by the author

jug!one or broken down into other (Rietveld 1979).

non-toxic substances ..... It now

becomes possible for us to under- The majority of existing literature on

stand some of the discrepancies in occurrence of walnut allelopathy involves the

the studies on walnut toxicity. If second type of plant association. These numerous

walnut bark or other plant parts reports of toxicity between existing walnut

4 are allOwed to become desiccated, trees and vegetables, field crops, fruits, and

no toxicity may be found. If the ornamentals are largely responsible for walnut's

roots of plants do not contact reputation as an allelopath. The literature on

plant parts containing juglone or these associations was reviewed by Brooks (1951) 

hydrojuglone, their oxidizing and more recently by MacDanlels and Pinnow

ability cannot produce the toxin." (1976).

Thus, the occurrence of toxic effects in The latter two plant associations involving

sensitive species growing near a walnut tree black walnut in plantations are the subject of

depends on whether they are exposed to juglone this paper and are discussed at length in the

as such. Juglone is a highly reactive sub- following sections.

stance and readily breaks down in well-aerated

soil. Some plants may avoid exposure to juglone

because their root systems are too shallow to

74
°

ALLELOPATHIC POTENTIAL OF BLACK WALNUT Effects of Juglone on Seed Germination a

ON PLANTATION VEGETATION Seedling Growth of Several Herbaceous

and Woody Species

Recent research has shown that mixed

plantings of certain nltrogen-flxlng species The following recently-completed exper

with black walnut in plantations can sub- tested the effect of juglone on several pla

stantially boost growth, and possibly quality growth processes in a variety of species. 

(Funk et al. 1979a, Van Sambeek and Rietveld experiment consisted of two parts: (I) see

1981).---O_er species are being considered as germination and radicle elongation in vario

possible co-crops with walnut to diversify juglone concentrations, and (2) shoot elong

vegetation and increase overall product yields, and dry weight accumulation in hydroponic 

However, we know nothing about the sensitivity tures containing the same juglone concentra

of these species to juglone.

The experiments reported here were con- Materials and Methods

ducted to assess the allelopathic potential of

black walnut juglone to several herbaceous and The following species were tested:

woody species which are being considered for

co-crops, nurse crops, an@ cover crops in Herbaceous legumes:

intensively cultured black walnut plantations.

Crimson clover (Trifolium incarnatum L.)

CroWn vetch (Coronilla varia L.)

Effects of Juglone of the Growth Hairy vetch (Vici____a villosa Roth.)

of Coniferous Seedlings Korean lespedeza (L_espedeza _ stipulacea

Maxim. )

In an earlier experiment reported else- Sericea lespedeza (Lespedeza cuneata

where (Funk et al. 1979b), seedling growth of (Dumont) G. Don)

four conifer species was tested in the laboratory for sensitivity to juglone. Seedlings Shrubs:

of Japanese larch (Larix leptolepis (Sieb. and

Zucc. )), Norway spruce (Picea abies (L.) Ginnala maple (Acer ginnala Maxim. )

Karst.), eastern white pine (Pinus strobus L.), Siberian peashrub (Caragana arborescensand Scotch pine (P. sylvestris L.) were estab- Lain.)

fished in a hydroponic system installed in a Russian olive (Elaeagnus angustif_olia L

growth chamber. The seedlings were grown for Autumn olive (Elaeagnus umbellata Thunb.

8 to i0 weeks in a nutrient-plus-juglone solu- Amur honeysuckle (Lonicera maackii Maxim

tion at juglone concentrations ranging from

10-2 Molar (M) to I0-I0 M.3 Trees:

At concentrations at 10-2 M and 10 -3 M, White oak (_ercus alba L.)

juglone was lethal to all species; Scotch pine White ash (Fraxinus americana L.)

and Japanese larch seedlings were killed at a Yellow poplar (Liriodendron tulipifera L

concentration of 10-4 M. Juglone caused no European black alder (Alnu______ss glutinosa (

visible injury to white pine_ at concentrations Gaertn.)

• of 10-6 M and less, and i0-5 M and less for Eastern white pine (Pinus strobus L.)

the other species, but seedling growth was Scotch pine (Pinus s_ylvestris L.)

inhibited by solutions as dilute as 10-7 M.

• Certain species were not included in b

All of the conifers tested were quite tests because of problems in obtaining, str

sensitive to Juglone and death resulted when lying, or germinating seed. Seed was colle

the Juglone concentration exceeded 10 -4 M. and stored until needed. Germination tests

Short-term exposure to intermediate concentra- were run in a laboratory germinator using 

tions resulted in measurable reductions in ard recommended pregermination treatments, 

plant dry weight without the appearance of conditions, and germination criteria (Assoc

toxicity symptoms. However, the effects of ation of Official Seed Analysts 1970, Inter

long-term exposures to low and moderate juglone national Seed Testing Association 1976, USD

concentrations in the field are unknown. Forest Service 1974). Four trays of i00 se

each were germinated in each of four Juglon

" concentrations: 10-6 M, 10-5 M, 10-4 M, an

10-3 M, plus a control (0 concentration). 

tical tests were run on two media, blotter

3Equi v alent percentage concentrations paper and soil.

ranged from 0.2 to 0.000000002 percent,

respectively.

r

L_J _ [_ ii J III I _ II I _ II II I . 
°

° •

When germination was occurring at a rapid more distinct than on shoot elongation. Dry

rate, i0 germinants were retained on each tray weight of white oak seedlings was not signiflfor measUrement of radicle elongation. Radicle cantly affected by juglone. In the remaining

length was measured initially and again after species, however, concentrations of 10 -5 M

10-15 millimeters of elongation had occurred and greater significantly inhibited dry weight

in the controls, usually 2-6 days. accumulation in all species except ginnala

• maple, Russian olive, and yellow-poplar (fig.

In the second part of the experiment, 2B). Plant dry weight accumulation was also

seedling s were grown in hydroponic culture to significantly inhibited by 10-6 M juglone in

test the effects of juglone on shoot elongation serlcea lespedeza and autumn olive. In three

and dry weight accumulation. Seedlings were species (Siberian peashrub, Russian olive, a.nd

grown in sand to the first true leaf stage, yellow-poplar), dry weight of seedlings grown

then transferred to nutrient solution contain- in 10-6 M and 10 -5 M juglone was higher than

ing the same juglone concentratiohs used in the in the control, but not significantly so. These

germination tests. The apparatus was the same responses are attributed to exceptional growth

unit described in the conifer growth experiment, of a few individual seedlings. More vigorous

Solutions were changed weekly. Tests ran 4-6 seedlings are apparently more resistant to

weeks, depending on rates of growth an& symptom Juglone.

development. Seedling height was measured

initially and repeatedly during the tests. At

the end of each test, seedlings were harvested Discussion

and plant dry weight determined.

• Every species tested was found to be

sensitive to juglone. All species were killed

Results by 10 -3 M juglone, and in most species many

seedlings were killed by 10-4 M juglone. The

Seed sermination.--Only the results using species varied independently in the growth proforest soil as the germination medium are cesses affected and in their degree of sensi-

.reported, since the results using the blotter tivity. Of the species included in all of the

medium were similar. Percent germination was tests, the five most sensitive to juglone were

significantly affected by juglone in only three sericea lespedeza, amur honeysuckle, hairy

of the 14 species tested: sericea lespedeza vetch, ginnala maple, and autumn olive; the

was inhibited by the 10 -6 M °and 10-3 M con- least sensitive species were white oak and

centrations, and white oak and amur honeysuckle Russian olive.

germination were stimulated by the 10-6 M concentration (fig. IA). Data from these short-term tests are useful for comparing species sensitivity to juglone

Radicle elongation.--Radicle elongation and the relative sensitivity of different growth

wasmore sensitive to juglone than was seed processes. However, biological assays are

•germination, with six of the 14 species tested insufficient as a means of identifying the

significantly affected (fig. IB). The pattern occurrence of allelopathy and the concentrations

of response varied by species, but the 10-3 M of chemicals responsible for allelopathy in the

concentration caused the most consistent and field (Stowe 1979). It is unlikely that 10-3 M

marked reduction in elongation. Radicle elon- juglone occurs under field conditions because

gation of amur honeysuckle and black alder was it is difficult to prepare in the laboratory, 

stimulated by the 10,6 M and. 10-5 M concentra- and some Juglone usually precipitated out in

tions, respectively, hydroponic culture. More likely, the allelo- 

pathic effects observed in the field are the 

ShoOt elongation.--All species were killed result of longer-term exposures to low and

by 10-3 M, and severely inhibited by 10-4 M moderate juglone concentrations under soil con-

' juglone. Five species (crimson clover, sericea ditions which favor juglone persistence and

lespedeza, amur honeysuckle, white ash, and increase plant susceptibility. The juglone

black alder) were significantly inhibited by toxicity experiments also suggest that low

the 10-5 M concentration, and amur honeysuckle Juglone concentrations may inhibit (or stimuseedlings Were also inhibited by 10-6 M juglone late) growth for a period of time before any

(Fig. 2A). 0nly severely inhibited seedlings toxicity symptoms appear.

(10-3 M, !0-4 M) showed visible symptoms

(chlorosis) of Juglone toxicity. Crown vetch "

was omitted because of its tendency to form a Significance of Black Walnut Alleopathy

basal crown rather than elongate, in Plantations

Plant .dry welght.--Juglone effects on Although every species tested was found to

plant dry weight accumulation were greater and be sensitive to juglone under short-term

76
.

120- HERBS SHRUBS s TREES

" O

_ 1

Z Z

O.O

W

J

CC CV HV KL SL GM SiP RO AO AH WO BA WP ScP

140- HERBS SHRUBS , TREES

$

•

..

• 

21

_im:**? ::? :T? ¢1-_::? .-:? _1- cp _:'? 6i-. S o1- v..

HV GM SiP RO AO AH WO WA BA WP 

Figure l.--Effects of juglone on: (A) seed germination and (B) radicle elongation of germina

seed of several herbaceous, shrub, and tree species. Responses to the four juglone concent

tions are given as a percentage of the control (0 concentration). Species abbreviations: 

Crimson clover, CV = crown vetch, HV = hairy vetch, KL = Korean lespedeza, SL = sericea les

' GM --glnnala maple, SiP = Siberian peashrub, RO = Russian olive, AO = autumn olive, AH = am

honeysuckle, WO = white oak, WA = white ash, YP = yellow-poplar, BA = black alder, WP = eas

white pine, ScP = Scotch pine. Each value is the mean of four trays of i00 seeds on forest

soil.

, 

! .

t
1. HERBS SHRUBS TREES

.J

_-_

_8

0_

-JOW °

Ow

0

' a,.

+

, cc HViii KL S, = SP RO AO AH WOWA BA _'P

14

HERBS SHRUBS TREES

-- 1

.J

• I--O

_:0

I_ -

Z _ °

<_ I -13.-1,1

t .o,,,

t+

Figure.2.--(A) Seedling shoot elongation and (B) plant dry weight of several herbaceous, shrub,

and tree species grown for 4-6 weeks in aerated nutrient solutions containing juglone. Growth

responses to the four juglone concentrations are given as a percentage of the control (0 concentration). Species abbreviations are the same as in figure i. Each bar is the mean of 12

seedlings.

78
labOratory conditions, the occurrence of allelo- species other than pines, conifers as a g

pathy under field conditions depends on several appear to be more sensitive to juglone th

important factors: (I) size and density of the deciduous species.

walnut trees; (2) the sensitivity of associated

species to Juglone; (3) soil conditions which European black alder has received in

control the disposition of Juglone, and (4) ing interest as a nurse crop species with 

management objectives--the intended purpose walnut in plantations. It is interesting 

and duration of co-planted species, note in table 1 that allelopathy occurred 

three out of seven mixed walnut/black ald

Information on several mixed, even-aged plantations. With close spacing, the ald

walnut plantations obtained from the litera- started dying in as little as 7-8 years. 

ture and gathered through personal contacts is the juglone toxicity experiments reported 

summarized in table i. ,Although specific this paper, black alder was one of the mo

information on the compatibility of walnut with sensitive species tested (figs. 1 and 2). 

other species and the factors that affect it ever, autumn olive, a recommended nurse c

o _ is not available, some general observations species (Funk et al. 1979a), was nearly a

J from the table and speculations will be dis- sensitive to juglone (figs. i and 2) but 

cussed in the following sections. , not yet shown any noticeable allelopathic

• effects in the field (table I).

.

The Buildup Period

Soll Factors

•There is a distinct difference between

allelopathY resulting from planting species The principal factor affecting the l

near existing large walnut trees and allelo- of the buildup period appears to be soil 

pathy in'mixed, even-aged plantations contain- dltlons, speciflcally soil moisture and s

ing walnut. In the former case, toxicity may aeration. Fisher (1978) found a strong r

occur within months or a few years, while in tionship between soil moisture and the al

the latter case there is a buildup period-- pathlc activity of walnut trees. As soil

the time required for walnut trees to grow to moisture increased from dry to wet, the a

sufficient size and density to have a signlfi- of extractable juglone and allelopathic a

cant chemical effect on the environment, increased. High soll moisture creates an

Knowledge of the relative length of the build- reducing conditions that are unfavorable 

up period and of factors that affect it are the chemical and biological oxidation of 

useful for silviculturalists wanting to grow Although there is no direct evidence of m

short-term crops of other species with walnut, breakdown of juglone, it seems most probab

that it occurs (Fisher 1978). Sol1 condi

A buildup period of approximately 12-25 also influence growth rates and vigor, wh

years is needed for planted walnuts to reach turn determine tree size and juglone prod

a sufficient size and density to produce and by walnut, and are related to susceptibill

release enough Juglone to result in noticeable associated species to juglone toxicity.

allelopathlc effects (table 1). It is unknown

when and for how long toxicity occurred before The relation between soil drainage 

symptoms appeared, sifice moderate Juglone con- interrelated soil" factors) and the occurre

centrations may inhibit growth without visible of allelopathy is evident in table I. Ea

. injury, on the other hand, allelopathy may not white pine planted on well-drained, coars

occur at all, even in sensitive species, if textured soils in Wisconsin, Ontario, and 

they are growing vlgorously on we11-dralned gan are growing well with walnut after 15

sites, and 44 years, while the same species grow

moderately-drained, finer-textured soils 

where were killed in as little as 13 year

Species Sensitivity On some well-dralned sites in Ontario, wh

pine has actually shaded out the walnut o

There is no doubt that species vary in period of 20 years (personal communication 

their Sensitivity to black walnut Juglone, as Dr. Richard F. Fisher). This implies tha

evidenced by Brooks' extensive surveys (Brooks nut interference to the growth of other s

1951), the Juglon e toxicity experiments report- is due both to competitive and a11elopathi

ed here, and table I. Of the plantations sum- factors, and the effectiveness of the lat

• marized in table i, walnut/pine mixtures were factor is controlled by soil conditions.

the most frequent and showed the most consistent occurrence of a11elopathy. Pines are

commonly planted and are especially sensitive

to Juglone. Although data are scarce for

.

III--
Table 1. Summaryof available data on compatibility of various species with black walnut in mixed,

even-agedplantations. The age and stze of walnut trees are those when toxicity

was first noted, or current data where no toxicity has occurred

, " : : Black walnut trees : Sotl : :

• : drainage Condition

" State Associated species Age Diameter1-/ class2/ associated species Source

(years) (inches) _

111inois Red pine 24 well Dead and dying Mr. HowardFox (retired)

Whitepine 24 well Dead and dying SinnissipplForest

Red pine 16 well Yellowing Oregon,IL

Ontario Whitepine 35 Dead and dying Fayle (1976)

&_Itepine 4 Growingwell

•Ontario Whitepine+ ' 30 well Growingwell Fisher(1978) Red pine

White pine+ 20 moderate Poor survival

Red pine and growth

White pine+ 20 'poorly Dead o _ Redpine J

Ontario Red pine + 21 moderate Deadand dying yon AIthen (1968) N. red oak , Growing*ell

Indiana White pine 23 8.4 moderate Yellowing and

declining Dr. ClairMerritt

. White pine 17 2.5 moderate Growingwell3J De_. Forestryand Natural

, Yellow-poplar + lg 6.3 moderate Growing well3_/ Resources

Redoak 1.2 Growingwell PurdueUniversity

_ack pine 16 5.1 moderate Growing *ell W. Lafayette, IN

Indiana White pine 13 4.2 moderate Deadand dying Mr. Robert O. Burke

White pine 13 3.6 well Yellowing Pierson-HolloweI1 Co.

Black alder 12 7.0 moderate Deadand dying Martinsville, IN

Autumnolive 14 5.5 moderate Growingwell

Autumnolive 14 4.4 moderate Growingwell

Autumnoltve 1¢ 4.8 moderate Growing well

, Missouri Black alder 8 2.9 well Deadand dying Dr. Richard C. Schlesinger

Autumnolive 11 4.6 Growing well Dr. Felix Ponder, Jr.

lllinois Blackalder 11 1.8 Growingwell North'Cent.For.Exp.Stn.

Autumnolive II 4.2 Growingwell Carbondale,IL

Black alder II 3.0 Growingwell

.Autumnolive II 4.g Growingwell

Black alder 7 2.7 Dead and dying

Autumnolive II 6.1 Growingwell

Black alder IS 6.0 Growingwell

Black alder 14 3.1 Growingwell

) Wisconsin White pine 15 4.8 *e11 Growing*e11 Mr. Ken E11is,Brooklyn,WI

. •

Michigan White pine 44 lO.O well Growingwell Mr. WalterLemmien

Whitepine 35 g.O well Pines closeto MichiganStateUniversity

BW dead EastLansing,Ml

Red pine 44 12.0 well Growingwell

Honey locust 40 7.0 well Growing*ell

Whiteoak 3g 7.0 well Growing*ell

Iowa Silvermaple 16 4.0 moderate Dying backand Mr; John L. McS*eeny

dead lowaState ConservationComn.

Redpine 8 2.5 moderate Yellowing and McGregor, IA

• declining

, Redpine 24 5.0 moderate Deadand dying

-- White pine 13 3.0 moderate Growingwell

Kansas Black locust" 31 7.0 well Growing well3_/ Hr. Nelson Rogers (retired)

, Bur oak + Green North Cent. For. Exp. Stn.

ash + E. red cedar + 32 7.0 well Growing well Salem, MO

Sycamore

Iowa White ash 12 4.0 moderate Growingwell Mr. Ed Gardlner

, IowaState Conservation Comm.

Anamosa, IA

Kansas Ash + hackberry 11 -- Growing well Mr. Gary G. Naughton

KansasState University

Manhattan,KS

• North Black alder 10 6.5 well Possibly declining Mr. Dwight L. Brennen_n

Caroltna North Carolina Forest Service

. Morganton, NC

Indiana Whiteplne +

Japanese larch + 12 -- well Growing well Mr. Richard Rambo

• Red ak + Redgum

Missouri Scotch ptne+ 12 3.5 moderate Growing well Mr. John P. Slusher

Blue spruce University of Missouri

1_/ Dtamoter at breast height, 4.5 feet above the ground. ColL_btam MO

2_/ Sotl drainage class gives an indication of sotl texture and organic matter content, and ts related to the degree

of aeration and moisture availability. Classes used are well-drained (well), moderately drained (moderate), and poorly

drained (poor).

• 3_/ Host black walnut trees shaded out.

80
o

Management Objectives Many changes will eventually occur in the

artificially created stands, both competit

The importance of black walnut allelopathy and allelopathlcally induced, that will r

is greatly influenced by the silvicultural in the less competitive, intolerant, and 

goals and the duration of the species co- sensitive species and individuals being e

planted with black walnut. Allelopathy does nated. These changes are likely to be mo

not appear to be a problem for growing short- abrupt and noticeable. Although juglone 

term crops of various herbaceous and woody tivity of most eastern hardwood species a

species with black walnut in plantations. Such to be less than that of conifers, the pot

short-term crops should be either harvested or for allelopathy in mixed plantations is g

expendable after 15 years. Even sensitive than in natural stands.

species can be considered for nurse crops or

Co-crops, if the benefits are worth the investment. • ALLELOPATHIC EFFECTS OF PLANTATION VEGET

- ON BLACK WALNUT

Pines can be given serious consideration

o ;._as a short-term nurse crop for black walnut on Black walnut plantations are commonl

well-drained sites. Pines produce dense side established on ex-agricultural land and o

shade needed to encourage height growth and fields. The vegetation consists of: (i

good form in the walnuts, provide w_nd pro- walnut and nurse crop (if any) seedlings, 

tectlon (especially in winter months), and (2) a diversity of volunteer herbaceous v

help shade out plantation weeds. If their tion. The herbaceous component is by far 

shape and color are good, some of the pines most abundant; thus, young tree plantation

can be harvested after 7-10 years and marketed essentially old fields for several years.

as Christmas trees, permitting recovery of Herbaceous plant succession occurs fairly

plantation establishment costs and thus increas- rapidly, following a general pattern of b

ing returns on the investment in walnut, leaved weeds giving way to annual grasses

to perennial grasses (Rice 1974). Recent

• When nurse crops are grown with walnut, research has shown that allelopathy is an

the phytotoxic activity of walnut may prove to important factor causing plant succession 

be a benefit by providing release from over- old fields (Rice 1974, 1979).

crowding.

Many of the same genera shown by Ric

The potential of allelopathy in lonjg-term group to be allelopathic to associated ve

mixed plantings with walnut is more uncertain, tion and microorganisms have been reporte

Long-term mixed walnut/pine plantings are not other investigators to interfere with tre

• recommended because it is too uncertain whether seedlings (table 2). Because of a lack 

the pines will survive to maturity. The corn- research, there are no specific reports 

patibility between black walnut and other hard- herbaceous vegetation allelopathically in

wood species is unclear. While on the one hand ing the growth of black walnut seedlings. 

several tree species (white ash, yellow-poplar, implications are: (i) there is an increa

black alder) were found to be sensitive to number of reports of certain herbaceous 

juglone in the experiments reported here, wal- releasing substances inhibitory to tree 

nut is commonly found associated with these lings; (2) many of these herbaceous speci

and many other important forest tree species of are abundant in black walnut plantations;

the eastern hardwood region (Brinkman 1957). (3) thus, the potential for interference 

If allelopathy is involved, then it is reason- black walnut seedling growth is great.

able to suggest that the influences are a matter

of degree--i.e., relative effects on the abun- Weed control is a necessary and high

dance, vigor, and growth of other species, recommended practice for establishing bla

This may help explain why black walnut, a rather walnut plantations (Schlesinger and Funk 

poor competitor, is able to exist in mature for without it seedlings are typically su

forest stands. Apparently, the species and for many years. Recent evidence suggests 

individuals present are those that have success- more is accomplished by weed control than 

fully (at least for the present) adapted to trolling competition; allelopathic intera

accommodate each other. The unsuccessful may also be controlled without knowing t

species and individuals have disappeared incon- exist. Weeds around individual seedlings

spicuously over a period of time. should be controlled for 2-3 years after 

• pl_nting to allow the tree seedlings to b

The situation in mixed, even-aged planta- established. After weed control is curta

tions may be different. Walnut is usually the surrounding herbaceous vegetation clo

planted at higher density and/or favored in back in, and the trees are susceptible t

thinnings because it is a preferred species, interference from herbaceous vegetation u

!

i 

i! ,

1
Table 2.--Summary of literature on allelopathlc effects of herbaceous vegetation

on tree seedlings 

Producing species Receiving species References

..

Bracken fern Black cherry Horsley, 1977a, 1977b

Wild oak grass

Wr inkl ed goldenrod

Fla_-topped aster

Hay-scented fern

New York fern

Short husk grass

Club moss

_, _ Broomsedge Loblolly pine Priester and Pennington

1978

Aster Yellow-poplar Haney 1969

Goldenrod Virginia pine

Ragweed Sugar maple Fisher et al. 1978

New England aster

Daisy fleabane

Hawkweed

Timothy

Tall buttercup

Canada goldenrod

Grass-leaved goldenrod

Orange hawkweed Balsam fir Dawes and Maravolo 1973

White pine

Mountain muhly Ponderosa pine Rletveld 1975

Arizona fescue

Tall fescue Sweetgum Welters and Gilmore

1976

Giant foxtall Loblolly pine Gilmore 1980

Tall fescue Loblolly pine Wheeler and Young 1979 

•

'" Tall goldenrod Black locust Larson and Schwarz 1980 

Broomsedge -

' Crownvetch

Wild carrot

Tall rescue

Timothy

they attain sufficient size to be unaffected. Schreb.). Besides the reports summarized in

That period may extend for i0 years or more. table 2, fescue has also been reported to be

toxic to the legumes blrdsfoot trefoil (Lotus

Of the herbaceous species listed in table corniculatus L.) (Peters 1968) and Ladlno

2, those considered to have the greatest allelo- clover (Trifollum _ L. cv. Tillman).

pathic potential to inhibit growth of black Fescue is common in established walnut plantawalnut seedlings are asters, goldenrods, rescue, tions. When heavy rescue sod in part of a 9-

and broomsedge. There is a growing body of year-old pure walnut plantation was rotovated

evidence on the allelopathic activity and com- in June 1980, a noticeable growth response

petitiveness of tall fescue (Festuca arundlnacea occurred the same season. With exceptionally

82
°

good rainfall early the following summer, the An alternative method to achieve both

released walnuts greatly expanded their foliage weed control and soll conditioning is to 

and were dark green, compared with unreleased llsh companion crops in plantations, i.e.

trees which grew only modestly and were light nurse crops and herbaceous cover crops th

green in color (personal communlcatlonwlth compatible and soil-buildlng. Ideally, t

Dr. Richard C. Schlesinger). species selected (e.g., pines, successiona

" woody species, exotics, and leguminous co

Besides possible allelopathlc effects, crops) should tolerate allelopathlc chemic

fescue is especially competitive to black in the soil. They should quickly develop 

walnut seedlingsand saplings. Todhunter and dense stands which exclude weeds (possibly

Beineke (1979) reported that tall fescue is allelopathlcally), enrich the soil through

acutely competitive with walnut seedlings for nitrogen fixation and/or addition of organ

s011 water, phosphorus, and potassium. They matter, create a favorable microclimate, 

suggested that fescue's'competitlveness is due minimally compete with the planted trees.

to its dense and deep rooting habit and heavy

infection of vesicular-arbuscular mycorrhlzae. Our initial research on establishing

_ _Holt and Voeller (1975) found that removing herbaceous, nltrogen-fixing cover crops i

fescue cover increased diameter growth and nut black walnut plantations has been successf

yield of i0- to 12-year old walnut trees. This (Van Sambeek and Rietveld 1981). Hairy v

evidence justifies the recommendation that has been especially promising because it

fescue not be used as a cover crop in black effectively suppressed weeds and stimulate

walnut plantations, walnut seedling growth. However, it overt

and deformed some of the shorter walnut s

Allelopathic chemicals from herbaceous lings. Korean lespedeza was not effective 

Vegetation may also inhibit certain micro- suppressing the tall summer weeds. Crimso

organisms essential to the growth of tree clover with Korean lespedeza suppressed 

seedlings. Persidsky et al. (1965) found that tall summer weeds, but not the warm season

Water extracts of prairie soils significantly grasses, especially giant foxtail (Setarla

• inhibited oxygen uptake by mycorrhlzal short faberli Lamb.). Serlcea lespedeza and cr

roots of Monterey pine (Pinus radiata D. Don.) vetch were slow to establish, but suppress

and red pine (P. resinosa Ait.), compared with weeds beginning the second year. Their e

extracts of forest soils. Theodorou and Bowen on seedling growth remain to be determined

(197-1) found thatdecomposition products of

grass roots reduced the number of infections Another potentially important role o

of an ectotrophic mycorrhizal fungus on tain companion crops is their ability to 

Monterey pine. Rice (1972) found that broom- soil microorganisms essential for tree gr

sedge inhibits Azotobacter and Rhizoblum, two Kormanik et al. (1980) found that seeding 

important nitrogen-fixing bacteria. Since millet, sudex, and sorghum as nursery cove

broomsedge is known to compete vigorously and crops increased inoculum density of vesicu

grow well on soils of low fertility, he sug- arbuscular fungi (Glomus spp.) in nursery 

gested that inhibition of nitrogen-fixlng and These are the same fungi that form entotro

nitrifying bacteria would keep the nitrogen mycorrhizal associations with black walnut

supply low and give broomsedge a selective roots, which are considered to be importan

advantage over species that have higher nitro- tree growth. Companion crops that coloniz

gen requirements, essential microorganisms in the soil need 

be tested in plantations to determine the

Soil conditioning is needed on sites that potential benefits to transplanted black 

have been dominated by herbaceous vegetation seedlings.

for a number of years. In the forest-pralrie

ecotone of north-central Oklahoma, Petranka

and McPherson (1979) found that bottomland Vegetation Management

forest trees were unable to invade climax tallgrass prairie without the prior invasion of The planting of nurse crops and cover

sumac (Rhus copallina L.) and other shrubs, crops in plantations, orchards, etc. is n

Upland forest trees were able to invade climax new concept in agriculture and forestry. 

prairie, but the invasion was enhanced by the obvious benefits of weed suppression and

pri0rinvasion of shrubs. Carmean et al. nitrogen-flxatlon have long been known. 

• (1976) found that growth of planted .hardwood companion crops have not been utilized fo

seedlings was strikingly better on areas that years because inexpensive and more convent

had recently supported some kind of tree cover, chemical fertilizers and pesticides were 

versus areas dominated by herbaceous cover, able to do the job.

They attributed the differences to several

physical, biological, and chemical soil factors, Recent escalation of costs of materia

. including allelopathy, and labor, and environmental concerns, hav

• . 
necessitated a renewed interest in companion identified: (a) natural forest stands contain- 

planting. However, besides renewed interest ing walnut as a component, (b) various species

there is increased awareness. It is becoming planted within the influence zone of existing

increasingly clear that plantation weeds do large walnut trees, (c) mixed, even-aged sapmore than compete with tree seedlings. Our ling plantations containing walnut, and (d)

increasing knowledge of plant/plant and plant/ transplanted walnut seedlings establishing

microorganism ailelopathy has made us aware admidst herbaceous vegetation. The latter two

that besides direct inhibition of plant growth plant associations are the subject of this

there may be indirect effects on growth through paper.

inhibition of beneficial and essential soll

microorganisms. The term "interference" 3. Laboratory tests of Juglone sensitivity

appropriately describes the situation, because of 18 species being considered for mixed plantit encompasses the overall deleterious effects ings with walnut showed that all were sensitive

o_ both competition and allelopathy in inter- to juglone. Seed germination and radicle elonplant relationships (Muller 1969). gation were inhibited mainly by high Juglone

concentrations, which were unlikely to occur

While weed control with chemical herbi- in nature. However, shoot elongation and dry

c!des may eliminate interference, companion ' weight accumulation were sensitive to Juglone

plantings of appropriate species have the concentrations as low as 10-7 M. Symptom

additional potential to condition and enrich development and death occurred only at very

the soll physically, chemically, and bio- high concentrations (10-4 M and 10-3 M). Conlogically to make it more favorable for tree ditions which result in allelopathic effects

growth. The modern version of companion plant- in the field are unknown, but are likely to be

ingin black walnut cultural systems is vege- a combination of longer-term exposures to

tation management. The concept of vegetation moderate juglone concentrations combined with

management in plantation establishment recog- soil conditions that favor Juglone persistence

nizes that there will be vegetation present and increased plant susceptibility.

. that competes with the trees. However, rather

thandealing with volunteer successional vege- 4. When walnut and other species are

tation (by repeated herbicide spraying and established together in plantations, there is

m0wing), selected compatible herbaceous and a buildup period of approximately 12-25 years

woody species are co-established with the tree before allelopathic effects become evident, if

seedlings. The companion species should be they occur at all. The length of the buildup

non-allelopathic (to walnut), minimally com- period depends on the age and density of walnut

petitive, and should suppress weeds and enrich trees, juglone sensitivity and vigor of assoclthesoil. The overall potential benefits are ated species, and soil conditions. Allelopathy

soll conditioning and enrichment, elimination is more likely to occur on imperfectly drained

of allelopaths, reduction of competition, soils where chemical and microbial oxidation

reduction of disease and insect damage, growth of juglone is restricted.

Stimulation, and improvement of tree quality.

Our continuing research will determine the 5. The importance of walnut allelopathy

extent of benefits and cost effectiveness of depends on silvicultural objectives: where

plantation vegetation management and will the intention is to grow crops with walnut

provide this information to landowners and beyond 12-25 years, the tree grower should be

managers. . cognizant of possible allelopathic effects; 

but where walnut is grown as the only eventual

crop, there is little reason to be concerned

SUMMARY, CONCLUSIONS, AND RECOMMENDATIONS about allelopathy. Moreover, walnut' s selective toxic effects may be beneficial for bringThe principal points made in the paper ing about its own release. Allelopathy does

are summarized as follows: not appear to be a factor discouraging the

planting of nurse crops, even pines, during

i. There is a great deal of literature the early part of the rotation.

on the toxic effects of black walnut that

creates the false impression that few species 6. There is a growing body of evidence

can be planted with walnut. Most of these which suggests that interference from plantareports involve toxicity to vegetables, field- tlon weeds may inhibit growth of tree seedlings

crops , fruits, and ornamentals, which are of during the establishment phase. It is quite

lesser interest to foresters. This paper possible that walnut will joint the list of

evaluates the importance of walnut allelopathy species affected. It is already known that

in forestry, plantation grasses, especially rescue, are

severely competitive to walnut. Fescue is not

2. Four types of plant associations recommended as a cover crop in walnut plantainvolving black walnut and allelopathy were tions.

84
°

7. Besides eliminating competition, con- treatise. VoI. IV. Academic Press, N

trolling weeds may also avoid allelopathic Ed. by J. G. Norsfall and E. B. Cowling

influences for the first 2-3 years after plant- Fisher, R. F., R. A. Woods, and M. R. Gal

ing. After weed control is curtailed, herb- 1978. Allelopathic effects of goldenro

aceous vegetation re-establlshes, and the and aster on young sugar maple. Can. 

extent of allelopathic activity is unknown. For. Res. 8:1-9.

Recentresearch on woody nurse crops and Funk, David T., Richard C. Schlesinger, a

herbaceous cover crops in plantations has Felix Ponder, Jr. 1979a. Autumn oliv

shown that these associations smother weeds a nurse plant for black walnut. Bot. 

and stimulate tree growth. 140(Suppl.):Sll0-Sll4.

Funk, David T., Paula J. Case, W. J. Riet

8. The concept of vegetation management and Robert E. Phares. 1979b. Effects 

involves co-establlshin_ compatible and bene- juglone on the growth of coniferous se

flcial companion species with tree seedlings lings. For. Scl. 25:425-454.

in plantations. The potential benefits are Gilbert, Barry L., James E. Baker, and Da

_soll conditioning and enrichment, elimination Norris. 1967. Juglone (5-hydroxy-l,4-

of allelopa_hs, reduction of competition, naphthoquinone) from Car__ o_vata, a de

reduction of insect and disease damage, growth rent to feeding by Scolytus multistriat

stimulation, and improvement of tre_ quality. J. Insect Physiol. 13:1453-1459.

Gilmore, A. R. 1980. Phytotoxic effects 

giant_foxtall on loblolly pine seedling

LITERATURE CITED Comp. Physiol. Ecol. 5:183-192.

Graves, Clinton H., Paul A. Hedin, and Vi

Association of Official Seed Analysts. 1970. E. Langhans. 1979. A survey of juglon

Rules for testing seeds. Proc. Assoc. levels among pecan, hickory and walnut

Official Seed Analysts 60(2):1-116. p. 113-121. In Proc. 72nd Ann. Cony.

Auyong, T. K., B. A. Westfall, and R.L. Southeast. Growers Assoc., Hilton Head

• Russell. 1963. Pharmacological aspects Gries, George A. 1943. Juglone, the act

of juglone. Toxicon 1:235-239. agent in walnut toxicity. North. Nut 

Brinkman, Kenneth A. 1957. Silvical char- Assoc. Annu. Rep. 32:52-55.

acteristics of black walnut. USDA For. Haney, Alan William. 1969. Effects of g

Serv. Cent. States For. Exp. Stn. Misc. rods and asters on establishment of tu

Rel. 22, 15 p poplar and Virginia pine in two old fi

Brooks, Maurice G. 1951. Effect of black in southeastern Pennsylvania. Diss. A

walnut trees and their products on other 29B:2697.

vegetation. West Virginia Univ _ Agric. Hedin, Paul A., Victor E. Langhans, and C

Exp. Stn. Bull. 347, 31 p. H. Graves, Jr. 1979. Identification 

Carmean, Willard H., F. Bryan Clark, Robert D. Juglone in pecan as a possible factor 

Williams, and Peter R. Hannah. 1976. resistance to Fusicladium effusum. J.

Hardwoods planted in old fields favored by Agrlc. Food Chem. 27:92-94.

prior tree cover. USDA For. Serv. Res. Holt, H. A. and J. E. Voeller. 1975. In

Pap. NC-134, 16 p. ence of weed control on growth and nut 

Davis, E. F. 1928. The toxic principle of ductlon of black walnut. North. Nut G

Juglans nigra as identified with synthetic Assoc. Annu. Rep. 66:144-145.

juglone and its toxic effects on tomato and Horsley, Stephen B. 1976. Allelopathic 

alfalfa plants. Amer. J. Bot. 15:620. ference among plants. II. Physiologic

Dawes, D. S. and N. C. Maravolo. 1973. Iso- modes of action, p. 93-136. In Proc.

lation and characteristics of a possible Fourth North Amer. For. Biol. Workshop,

allelopathlc factor supporting the dominant Syracuse, NY.

role of Hieracium aurantiacum in the bracken- Horsley, Stephen B. 1977a. Allelopathic

grasslands of northern Wisconsin. Trans. inhibition of black cherry by fern, gr

Wis. Acad, Sci. 61:235-251. goldenrod, and aster. Can. J. For. Re

Fayle, David C. F. 1976. Kaleidoscope. For. 205-216.

Chron. 52:265. Horsley, Stephen B. 1977b. Allelopathic

Fisher, R. F. 1976. Allelopathic interference inhibition of black cherry. II. Inhi

among plants. I. Ecological significance, by woodland grass, ferns, and club mos

p. 73-92. In Proc. Fourth North Amer. For. Can. J. For. Res. 7:515-519.

• Biol. Workshop, Syracuse, NY. International Seed Testing Association. 

Fisher, R. F. 1978. Juglone inhibits pine International rules for seed testing. 

growth under certain moisture regimes. J. Sci. and Technol. 4:3-49, 51-177.

Soil Sci. Soc. Amer. 42:801-803. Kochhar, Medha, Udo Blum, and Robert A. R

Fisher, Richard F. 1979. Allelopathy. p. 1980. Effects of 03 and (or) fescue o

313-330. In Plant disease: an advanced clover: interactions. Can. J. Bot. 5

249.

• " 

t

I

%

:.,,#
°

i Kormanik, Paul P., W. Craig Bryan, and Richard Rietveld, W. J. 1975. Phytotoxic grass

i C. Schultz. 1980• Increasing endomycorrhi- residues reduce germination and initial

zal fungus inoculum in forest nursery soil root growth of ponderosa pine• USDA For.

with cover crops• South• J. Appl. For. 4: Serv. Res. Pap. RM-153, 15 p.

151-153. Rietveld, W. J. 1979• Ecological implications

i KraJci , W. M. and D. L. Lynch. 1978. The of allelopathy in forestry, p. 91-112. l__nn

i inhibition crude walnutofhuvallrioexustracmitcsro-and organiJusgmlsone.by Pro Foresc.tsRe, gene JohnratinS.g WriOaks ght inForesUptlarynd CoHanference rdwood ,

Microbios 4:175-181. W. Lafayette, IN.

i Lars0n, M. M. and E. L. Schwarz • 1980 • Allelo- Schlesinger, Richard C • and David T • Funk •

j pathic inhibition of black locust, red clover, 1977. Manager's handbook for black walnut• and black alder by six common herbaceous USDA For. Serv. Gen. Tech. Rep. NC-38, 22 p.

species• For. Sci. 25:511m520. Sondheimer, Ernest and John B. Simeone, eds.

• Lee, K. C. and R. W. Campbell. 1969. Nature 1970. Chemical ecology. Academic Press, NY.

occurrence Juglone _ nigra 336 p.

and of in

L. Hortsci. 4:297-298. Stowe, Lawrence G. 1979. Allelopathy and its

MacDaniels, L. H. _nd David L Pinnow• 1976. influence on the distribution of plants in

Walnut toxicity , an unsolved problem. _orth. an I11inois old field. J. Ecol. 67:1065-

Nut Growers Assoc. Annu. Rep. 67:114-121. 1085.

Marking, Lelf L. 1970. Juglone (5-hydroxy-1, Theodorou, C. and G. D. Bowen. 1971. Effects

4-naphthoquinone) as a fish toxicant. Trans. of non-host plants on growth of mycorrhizal

Amer. Fish Soc. 99:510-514. fungi of radiata pine. Aust. For. 35:17-22.

Muller, Cornelius H. 1969. Allelopathy as a Thomson, R. H. 1971. Naturally occurring

factor in ecological process • Vegetatio quinones • 2nd ed. Academic Press, NY • p •

Nation 18:34al8-35A7.cademy of Sciences• 1971• Biochemi- Todh271 unt-272 er,. Michael N. and Walter F. Beineke.

•i cDC.al i1nt34erap.ctions among plants• -Washington, 1growth• 979. Effec Treet ofPlanters' fescue onNotesblac30(3 k wa):20-2 lnut 3.

i Persidsky, D. J , H. Loewenstein, and S A United States Department of Agriculture, Forest ' • • •

Wilde. 1965. Effect of extracts of prairie Service. 1974. Seeds of woody plants of

! soils and prairie grass roots on the the United States. U. S. Dep. Agric.,'Agric.

! respiration of ectotrophic mycorrhizae. Handb. 450, 883 p.

Agron. J. 57:311-312. Van Sambeek, J. W. and W. J. Rietveld. 1981.

Peters, E. J. 1968. Toxicity of tall fescue Seeding forage legumes in black walnut planto rape and birdsfoot trefoil seeds and rations. Walnut Council Bull. 8(1):6-8.

seedlings. Crop Sci. 8:650-653.. von Althen, F. W. 1968. Incompatibility of

Petranka, James W. and James K. McPherson. black walnut and red pine. Bi-Month. Res.

1979. The role of Rhus copallina in the Notes 24(2):19.

dynamics of the forest-pralrie ecotone in Walters, D. T. and A. R. Gilmore. 1976.

north-central Oklahoma. Ecol. 60:956-965. Allelopathic effects of fescue on the growth

Priester, David S. and M. T. Pennington. 1978. of sweetgum. J. Chem. Ecol. 2:469-479.

Inhibitory effects of broomsedge extracts Wheeler, G. L. and J. F. Young. 1979. The

on the growth of young loblolly pine seed- allelopathic effect of fescue on loblolly

iings. USDA For. Serv. Res. Pap. SE-183, pine seedling growth. Arkansas Farm Res.

7 p. 28(2) :6.

Rice,_ Elroy L. 1972. Alrelopathic effects of Whittaker, R. H. and P. O. Feeney. 1971.

Andropogon virginicus and its persistence Allelochemics: chemical interactions

in old fields. Amer. J. Bot. 59:752-755. between species. Science 171:757-770.

Rice, Elroy L. 1974. Allelopathy. Academic

Press, NY. 353 p.

Rice, Elroy L. 1979. Allelopathy--an update.

B0t. Rev. 45:15-109.

86
o

PRUNING FOR QUALITY

Richard C. Schlesinger I

Abstract.--Artificlal pruning can improve tree quality

but can reduce growth and quality if incorrectly done.

Pruning causes wounds and pruning of live branches may reduce

growth. Corrective pruning is not generally useful for the

development of high-quality plantations. But lateral pruning

o _ is needed and should be done in stages beginning when the

trees are small. By understanding tree responses to pruning,

we can improve tree quality and plantation value through

proper pruning practices.

Black Walnut (Juglans nigra L.) veneer logs could be reduced growth or the tree's atte

generally command prices 8 to 9 times higher to compensate for the loss of its solar co

than saw logs. But without some artificial tors by excessive height growth or by prod

pruning, few black walnut trees develop the of new branches on the bole (sprouting).

straight, clear boles needed for veneer unless

we are willing to extend the growing period Pruning also causes wounds (Shigo et 

beYond 80 to i00 years. Although artificial 1979). While the wound is open, disease

pruning can improve tree quality, it can also organisms may gain entry and cause decay 

reduce growth and quality if carelessly or discoloration of the wood. Wound healing

incorrectly done. By understanding tree involves the isolation of the wounded area

response to pruning, the grower can determine (compartmentalization) and the closure of 

how best to prune an individual tree. wound by new wood overgrowing the wound. 

process may result in zones of weakness i

wood that can lead to ring shake.

TREE GROWTH AND.RESPONSE

Black walnut does not prune itself w

The tree has been likened to a tower sup- even under the crowded conditions that ar

porting an array of solar collectors (Wilson for natural pruning. Especially under sh

and Archer 1979). But it is much more supple rotation intensive culture, artificial pru

than a tower, especially when small. Many of live branches or dead branches and stub

young walnut trees develop straight, single will be needed for veneer production. How

stems, but others may become crooked or only those selected as potential crop tree

multiple-stemmed as the result of insect, will need to be pruned.

animal, or weather damage. Yet, there is a

tendency for such trees to straighten and for

one leader of a multileader tree to gain PRUNING PRACTICES

dominance (Schlesinger and Bey 1978). Thus,

many trees will overcome apparent form defects Corrective prunlng.--Correcting poten

by themselveS if left alone, form defects, especially multiple leader 

lems, is usually the first use of pruning 

Removing some of the tree's solar collec- walnut plantings (Bey 1976, Beineke 1977, 

tors can reduce growth. Basically, pruning of 1966). The objective is to produce trees 

• live branches is a dwarfing practice (MacDaniels straight, single stems. If two or more l

1973). The greater the proportion of the llve are competing for dominance, all but one 

crown removed, the greater the chance of an removed. When no high-quality leader is 

undesirable response by the tree. This response the tree can be cut (coppiced) near the g

• line, and the best leader can then be sel

from the resulting stump sprouts. The ma

1princlpal Silviculturist, North Central concern with corrective pruning is that r

Forest Experiment Station, Forestry Sciences too much of the llve crown of a small tre

Laboratory, Carbondale, Illinois. reduce growth or create new stem-form pro

. °

i
The l_mmediate, apparent benefits from Table 2.--Average tree size in 1978 for Illinois

corrective pruning may not last. von Althen study.

(1977) found that seedlings severely injured

by a June frost benefited from pruning or

coppicing. Three years after treatment, 42 Tree size

percent of the coppiced trees and 31 percent Diameter breast

of the pruned trees were classified as excel- height Height

lent or good, but only ii percent of the un- Year Not Not

treated trees were so classified. However, a coppiced pruned Pruned PrUned Pruned

study in southern lllinois 2 showed that the

apparent improvement in tree form soon after - - - cm ...... m ....

treatment may disappear. Trees planted in

1967 were ¢oppiced in 1969, 1970, and 1972, or Not coppiced 6.6 6.7 4.7 4.5

not at all. Half of the trees were correc- 1969 6.8 5.9 4.6 4.3

tive!y pruned as needed beginning in 1967 and 1970 6.0 6.3 4.1 4.3

continuing until 1975. Tree form ratings in 1972 4.9 4.8 3.8 3.7

1976 sho'wed no significant effects of corrective pruning but trees coppiced in 1972 had

significantlybetter form. However, by 1978

therewere no significant differences in tree Table 3.--Potential crop trees within each

quality or between any of the treatments treatment group

(table I).

Corrective pruning can have a dwarfing Crop trees I

effect. In yon Althen's study (1977), the Year Not

coppiced trees were II percent shorter and 20 cop piced pruned Pruned _

percent smaller in diameter than the control

L trees after 4 years. The pruned trees were 3 .... Percent ....

percent shorter and 4 percent smaller. In the

southern Illinois study, both tree height and Not coppiced 44 37

diameter were significantly reduced by coppicing 1969 26 32

in 1972 but not by corrective pruning (table 2). 19,70 32 32

Moreover, potential crop trees, identified on 1972 16 16

the basis of both size and quality, were more

numerous within the untreated group than within

any of the other treatment groups (table 3). iTrees that were average or above average

, in quality and size.

Table l.---Comparison of tree quality in 1978 for Illinois study

Tree_ quality_ ....

Excellent Poor and

and good I Fair impossible

Year Not Not Not

coppiced pruned Pruned pruned Pruned pruned Pruned

• Percent

Not coppiced 44 37 26 33 30 30

1969 37 37 47 16 16 47

1970 58 37 26 42 16 21

1972 58 53 26 15 16 32

iThe trees were rated on a scale of i to i0 as to their potential to develop into hlgh-quality trees.

2Study No. NC-II08, CH-422, data on file Thus, corrective pruning should be pracat the Forestry Sciences Laboratory, Carbondale, ticed with restraint, if at all. Generally

IL. ' not all trees are needed for crop trees.

88
o

°

Because_many trees will "correct" themselves Clark and Seidel (1961) found that 

within a year or two after developing a form old trees could be heavily pruned once w

problem, delay in pruning may result in the; significantly reducing growth. Ten year

disappearance of the need for it. If a tree treatment, trees pruned of 75 percent of 

is pruned, the least amount needed to do the llve crowns had grown as much in diameter 

job should be done. And coppicing in March, trees pruned by lesser amounts or left u

April, or early May Will result in less growth However, annual pruning for 6 consecutive 

loss than if done in June or July. 3 reduced tree diameter when 80 percent of 

bole was cleared (table 4). Trees plant

Lateral pruning.--The objective of lateral 1969 were first pruned in 1975. Three y

pruning is to remove obstacles (branches or of annual pruning did not reduce tree si

stubs) to the formation of clear, defect-free (Funk 1979). However, continued treatmen

wood on the lower stem of a tree. Basic to an additional 3 years resulted in smalle

the development of pruning recommendations are diameter trees when 80 percent of the bo

the following considerations: (i) tree growth cleared, although tree height was not si

should not be reduced by the removal of too cantly affected. Diameter growth at bre

oJ _ many llve branches at any one time, and (2) height during the sixth year was signific

wound healing should be encouraged, less for the 80 percent pruned trees tha

, lesser treatments (table 5).

Table 4.--Tree size after 3 and 6 years of annual pruning

Diameter at

Percent of Height Diameter at 0.3 m breast heisht

height pruned 3 years 6 years 3 years 6 years 3 years 6 years

m cm

0 3.3 4.5 7.8 ii.0 4.9 7.8

20 3.2 4.3 7.2 i0.0 4.3 7.3

40 3.4 4.5 7.5 10.4 4.8 7.7

60 3.6 4.9 7.5 10.3 5.3 8.0

80 3.6 4.8 6.5 8.6 4.5 6.6

Table 5.--Treatment response during third and The tree may respond to heavy prunin

sixth years of annual pruning producing sprouts. Clark and Seidel (19

noted sprouts on 50 percent of the trees

pruned of 75 percent of their live crown

Percent of DBH growth No. sprouts only 6 percent of the trees pruned of 25 

heisht pruned 6th year 3rd year 6th year cent of their live crowns produced sprou

Funk (1979) found an average of 6.7 spro

cm per tree for the 80 percent treatment in 

third year, and 10.7 new sprouts were pr

0 1.2 0.i 0.i during the sixth year of the study (tabl

20 1.0 0.2 0.0 This rebuilding of the live crown may he

40 0.9 0.6 0.4 tree maintain its growth rate, but it ne

60 0.8 1.3 2.9 the potential benefits of pruning for th

80 0.6 6.7 i0.7 duction of clear wood.

The wounds that result from either 

• or artificial pruning must heal cleanly 

objectives of pruning are to be met. Th

extent of fnternal defects (staining and 

shake zones) is related to the size of t

wound, the number of wounds within a seg

of the bole, and the season of year when 

wounds are made (Shigo et al. 1978, Shig

3Data on file at the Forestry Sciences al. 1979, Smith 1980). Branch collars t

Laboratory, Carbondale, IL. form around dead or dying branches are p

!

b

|

i

_j _ • ,
, the healing process, and thus removing these SUMMARY

collars rewounds the tree (Shigo et al. 1979).

Open wounds are infection courts for disease Patience and understanding are the keys

i organisms such as wood decay fungi, to pruning for quality. Generally 9 corrective

pruning appears to be of llttle or no value in

Heavy pruning can also lower tree quality, intensive culture, although there may be a few

primarily because of the additional wounds exceptions. Allowing trees to straighten

created by the pruning of sprouts. In the naturally if possible and removing the lowsprUning outhern toIllclear inois 80study, percenatnnuoafl,therepeboaletedresult- qual in aithigh-quali y trees tiyn tplan hinntiantgison.will Careful, normally tiresul melyt

i ed in significantly fewer hlgh-quality trees lateral pruning of potential crop trees will and more lower quality trees (table 6). On result in the development of clear wood and

the other hand, no pruning and clearing only high-value trees.

20percent of the bole also resulted in fewer

high-quallty trees than the 40-percent and 60-

} percent-treatments (table 6). LITERATURE CITED

Beineke, Walter F. 1977. Corrective pruning

i Table 6.--Tree quality I after 6 years of annual of black walnut for timber form. Purdue

pruning Univ. Coop. Ext. Serv. FNR-76, 5 p.

Bey, Calvin F. 1976. How to "train" black

walnut seedlings. U. S. Dep. Agric. For.

Percent of Excellent Poor and Serv. Leafl., 4 p. North Cent. For. Exp.

height pruned and good Fair impossible Stn., St. Paul, MN.

Clark, F. B. 1966. Culture of _m,_ture trees.

i Percent p. 42-46. In Black walnut culture. U.S.

Dep. Agrlc.-Tor. Serv., North Cent. For.

0 33 57 i0 Exp. Stn., St. Paul, MN.

20 28 62 I0 Clark, F. Bryan and Kenneth W. Seidel. 1961.

}! 40 54 33 13 Growth and quality of pruned black walnut •

1 .. 60 47 35 18 U.S. Dep. Agric. For. Serv., Cent. States

i 80 23 42 35 For. Exp. Stn. Tech. Pap. 180, ii p.

i • ,, • , , , Funk, David T. 1979. Stem form response to

repeated pruning of young black walnut trees.

1See footnote for table 1. Can. J. For. Res. 9:114-116.

MacDaniels, L. H. 1973. Fundamentals of tree

• pruning with special reference to the black

For best results, lateral pruning should walnut. North. Nut Grow. Assoc. Annu. Rep.

be done in stages, beginning when the trees 64:29-42.

(.and thus the branches) are small (3 to 4 m Schlesinger, Richard C. and Calvin F. Bey.

tall). Between 40 to 50 percent of the tree 1978. Natural improvement in black walnut

height should remain with branches. If clusters stem form. p. 389-400. _..._ In Proc. Cent.

of branches are present, not all branches should Hardwood For. Conf. II. West Lafayette, IN,

beremoved at one time. Pruning in the spring Nov. 14-16, 1978.

Just before bud break avoids the fall spore Schleslnger, Richard C. and David T. Funk.

production period of many disease organisms 1977. Manager's handbook for black walnut.

• and mlnlmlzes the time before the wound begins U.S. Dep. Agric. For. Serv., Gen. Tech.

tO close. And spring wounds result in less Rep. NC-38, 22 p. North Cent. For. Exp.

discolored and abnormal wood than fall wounds Stn., St. Paul, MN.

(Smlth1980). If branch collars are present, Shigo, Alex L. 1980. Branches. J. Arborlpruning Should remove the branch flush to the culture 6(11):300-304.

outer edge of the collar, not flush to the main " Shigo, Alex L., E. Allen McGinnes, Jr., David T.

stem. Funk, and Nelson F. Rogers. 1979. Internal

defects associated with pruned and nonpruned

Perlodic pruning should continue until the branch stubs in black walnut. U. S. Dep.

desired clear length is obtained. Theoretical Agric. For. Serv. Res. Pap. NE-440, 27 p.

economic analysesgenerally support a 5.2 m Northeast. For. Exp. Stn., Broomall, PA.

clear length for veneer production and a 2.6"m Shigo, Alex L., Nelson F. Rogers, E. Allen

clear length for nut production (Schleslnger McGinnes, Jr., and David T. Funk. 1978.

andFunk 1977). Black walnut on Kansas strip mine spoils:

some observations 25 years after pruning.

U. S. Dep. Agric. For. Serv. Res. Pap. NE-393,

14 p. Northeast For. Exp. Stn., Broomall, PA.

9O
smith, Desmond E. 1980. Abnormal wood

formation following fall and spring

injuries in black walnut. Wood Sci. 12:

243-251.

yon Althen, F. W. 1977. Corrective pruning

of black walnut seedlings injured by a late

" spring frost. Canadian Forestry Service,

Ontario Information Rep. 0-X-265, 8 p.

Wilson, Brayton F. and Robert R. Archer. 1979.

Tree design: some biological solutions to

mechanical problems. BioScience 29:293-298.

| '
°

!

PRINCII_.wROF MANAGINS BLACK WALNUT IN NATJRAL

i Burnell C. Fischer2

! Abstract.--_e management of black walnut in natural

stands is basically the cumbination of strategies normally

"_ employed in managing natural stands and the intensive

cultural practices developed for plantations. These.dual

strategies, if carefully thought out in the planning process

, and then implemented, can result in the successful

regeneration, growth an_ development of black walnut trees in

natural woodlands.

___

i IN_RCDUCTIDN Management Planning

The intensive culture of black walnut Most "forest management, in natural

| Plantations tends to duminate the discussion woodlands has been custodial in nature. _hat

aptroduactiwaln on uftrummeetinatng.ural wHowe oodlavendr,s tiasmbera meis,rchanttimbe abler anisd desiharvrabested le for whthene owniter, isa

management objective provides significantly new stand is then allowed to regenerate and

i more income to private, nonindustrial woodland grew as it will, and timber is again harvested

!; owners than plantations, when it becumes merchantable and advantageous

*_ to the owner. This type of management

Black walnut trees are usually a very requires little, if any planning and results

small cumponent of natural stands, generally in very few timber management expenditures for

! appearing as scattered single trees or in the woodland owner. However, custodial

.small isolated groups. However, .becauP._eof management usually results in relatively few,

its potential high timber value, full widely spaced (in time) financial returns for

oonsideration should be given to the the woodland owner. Also, such management

possibility of incorporating the intensive generally does not favor the regeneration,

•' culture of individual black walnut trees into development and growth of black walnut trees.

the management of natural woodlands. This is particularly true when the forest

management practiced is ,partial cutting",

The objectives of this paper are where a residual stand of small and/or lower

tWo,fold. First, I wish to briefly review the quality trees is left.

steps, necessary in developing a forest

management plan for a natural woodland and the Managing timber, whether in natural

special considerations that can be made for stands or plantations, is a major project

black walnut tree management. Secondly, I requiring a high degree of planning. This

will comment on several cultural practices for planning should result in the development of a

black walnut tree management in natural forest management plan for the woodland and

stands, the consideration of the position of the

woodland in relation to the other activities

(investments) of the woodland owner. Both of

. these steps are of vital importance because of

• the extended time period resources are tied up

ipaper presented at the 1981 Joint before either a return is realized or the

Meeting of Walnut Council/Northern Nut Growers accumulated wealth in the timber and land is

Association, W. Lafayette, Indiana, Aug. 9-14, passed on.

1981 "2

" Associate Professor of Silviculture, A forest management plan is essential if

Department of Forestry and Natural Resources, the woodland owner is to maximize current

Purdue University, W. Tafayette, Indiana income and wealth accumulation within the

47907. • forest's biological constraints and site

• 92
°

limit@tions, and his landownership objectives, previously contained higher population

As with the management of any investment, black walnut than at present.

professional guidance and assistance is

strongly r_ended. Unless the landowner is The second part of the inventory pro

trained in forestry he should seek the advice is the "timber cruise". The sam

and skills of professional foresters, intensity of the timber cruise is relate

Foresters working for the State, Cooperative the ownership objectives and characteri

Extension Service, Soil Conservation Service, of the woodland. The timber cruise shou

forestry consultants and industrial foresters conducted by a forestry professional. 

.can all be helpful, timber cruise the forester determines 

species, diameter, height, quality, vigor 

The development of a forest management past growth rate of sample trees. The 

plan can be explained as a four step process, collected on the timber cruise can be uti

The _ and continuing step is that made by in determining the structure (tree 

the woodland owner in clearly defining his distribution), stocking (density), pul

ownership objectives. Foresters and other and/or sawtimber volume, present value, g

professionals can aid in this decision making potential a_d earning potential of the w

' process by proposing different alternatives woodland as well as for separate por

and projected potential incomes from the (stands) of the woodland.

forest. However, itmust be emphasized that

the final objectives be those of the woodland Because of the potential high ma

owner and not the assisting forestry value: and increased management act

- professional, directed toward black walnut trees it ma

wise to more intensively sample the w

Second is the cumpletion of an inventory, tree population in a natural woodland. 

This is simply the gathering of the data ultimate would be to identify and record 

necessary to evaluate the woodland potentials walnut tree and its location in the wood

and opportunities, so that timber management This intensity may not be justified in 

. strategies such as thinning schedules, cutting situations but careful consideration shou

budgets, planting regimes, improvement given to sampling intensity by a woo

cuttings, logging road construction, timber owner and his forester. For exa

tax management, and individual black walnut intensively inventorying the more val

tree Culture can be developed. The data trees would be of great help in establi

gathering can be divided into two parts. The the financial basis should a loss of 

first part, sometimes called a reconnaissance occur.

cruise, consists of the determination of

property boundaries, an accurate calculation The third step is the actual develo

of acreage, determination of soil and of a forest management plan. This wr

topographic conditions, procurement of maps plan is the combining of the (xqn

and aerial _hotos of the woodland, an objectives and inventory data. The final 

accounting of property taxes and other should include a description of the wood

nonmanagement costs of holding the land and a a statement of c_ership objectives and g

description of the land-use history of the maps and aerial photos, sum_ries of inve

woodland. The more completely this first part data, a timber/cash fl_ analysis, and a 

' of the inventory process is carried out, the I0 year annual plan of work. A sep

moresuccessful the data collected in the portion of the plan may be devoted to the 

".timber cruise" in the second part of the intensive cultural management of indivi&_

inventory can be interpreted and utilized in groups of black walnut trees. M_st woo

developing the forest management plan, management plans appear rather standar

with little individuality, such as a sep

' To the person interested in black walnut walnut portion. This usually means 

' two aspects of the reconnaissance cruise are landowner has not identified hi_ objec

of particular importance. First is the soil but followed the ideas of a fore

survey. By delineating the differing soil Finally, additional provisions for upd

• Conditions for a woodland, the woodland owner and revising the plan, as well as 

can determine which sites are suitable for additional inventory data should be cl

black walnu£ trees. This should prevent indicated.

future errors in establishing and managing

black walnut "off-site". The second aspect is The _ and final step is a conti

• that of land-use history. A thorough analysis task for the woodland c_ner. He 

•of past timber sales, and management implement the plan. Also on a regular 

activities may indicate if the woodland he must record work progress, all expense

incumes, review and plan for future 

if i ...... |i i i.....
°

schedules, and evaluate the plan's continued Pruning of branches results in improved future

desirability, individual tree stem quality.

As the woodland c_ner evaluates his Thinnings are desirable to control stand

woodland management operation he should density, particularly in even-aged stands.

continue to include and consider the woodland Studies have shown that trees, even in older

investment as part of his total investment sawtimber sized stands, respond with increased

portfolio. _his will require the woodland diameter growth after thinning (Hilt, 1979).

owner to review his present and projected Stocking guides for a number of species

returns and expenses with his tax accountant including black walnut are presently available

and financial advisors. _his will all(M for (Sc/_esinger and Funk 1977).

the woodland owner to balance the long-term

and asset accumulation aspects of his Release cuttings, particularly to

timberland with his investment portfolio and stimulate the gr(_eh of selected hardwood crop

estate pl_ for maximum efficiency and trees in stands less than !0 years old, are of

profit@bility. ' questionable value. Such release cuttings

have not significantly improved height or

Cultural Practices diameter gr(m_c_ or length of clear stem, nor

' pcevented crown-class regression in black

Timber production inherently implies cherry and yell_ poplar following treatment

growing trees for harvest. Forest management (Smith, 1979). Some researchers nm_ suggest

pr ds on the basic assumption that the that entry into young even-aged hardwood

vegetation on any site normally tends to stands less than 20 years old may be

extend itself aggressively to occupy the unsuccessful in stimulating growth response.

available growing space. If the vegetation However, if the objective tO-enter young

fills the growing space, the only way that the stands is to change species composition (i.e.,

forest can be _mnged or controlled is by remove dominant undesirable species)then such

removing (i.e. cutting) trees. _hus, cutting a treatment may_ still be Possible.

is important not only as a means of harvesting

trees for income, it is the means by which Also, grapevine control in such young

forests are re-established and tended, stands may be required to reduce damage "and

allow future crop trees to develop.

Basically, cuttings are made to either Grapevines can be a significant hinderance to

prcmote the grm_h of desirable trees already young stands, particularly on very Productive

in existence- an intermediate cutting, or sites (Trimble and Tryon, 1979; Smith 1979).

' Provide room for the establishment of new

trees- a reproduction/ harvest cutting. Both Improvement cuttings (commonly called TSI

Of these types of cuttings can be used to if not a timber harvest)are generally made in

increase the numbers and gr(_ch of black previously unmanaged stands and take the form

walnut trees in a natural woodland, of removing cull trees or ic_-value species.

The goal of such an operation is to increase

Black walnut require nearly full sunlight future stand value by removing trees of little

to survive and grow as a seedling or sapling, or no economic value and by providing space in

In fully stocked forests it must be in a which higher quality and high-value species

..dominant or codominant crown position to can develop. Black walnut trees have been

" maintain- itself. .Thus,.cultural Practices shown to be an excellent "candidate" tree to

directed towards growing existing black walnut favor in TSI (Phares and Williams, 1971).

or the establishment of new seedlings must be

concerned with this intolerance to shading A concern that has recently arisen with

(Sch!esinger and Funk 1977). TSI is the potential problem of "flashback"

when using picloram (Tordan 101R) in stands.

Intermediate Cuttings Flashback refers to the herbicide damage to

' adjacent untreated vegetation via root grafts

Intemediate cuttings are made during the or soil moisture movement. Yellow poplar is

long time period between the establishment of particularly sensitive to picloram. Black

a new Stand of trees and its eventual harvest, walnut has generally not shown to have this

Intermediate cuttings vary in objectives, sensitivity problem. Practices that may avert

Thinnings primarily regulate stand growth by the problem include monitoring dosage rates so

-varying stand density. Release and that excess amounts of herbicide are not

improvement cuttings are designed to regulate applied to injected trees, girdling trees

the species cunposition and improve the rather than injecting herbicides and using

quality Of very young and older stands.

94
°

aiterna£iv@ herbicides such as gly_hosate crown position. A second and often 

(Roundup)." ignored cultural practice is the main

of the opening/patch clearcutting ove

Many landowners have invested time and Smaller dimension openings, whic

money in pruning because of the veneer and generally favored by woodland owne

high quality sawlog potential of black walnut, small land holdings, must be perio

Pruning in plantations is usually necessary, enlarged by cutting the border ov

especially those of wider spacing (Beineke, trees. If ignored, the subsequent gr

1977). _his is less of a problem in natural residual overstory trees bordering a 

stands, however, pruning can be considered as opening can dramatically reduce direc

an investment alternative. In theory this is radiation levels. Fischer (1979) pr

a prudent investment because as a result of that small circular forested openings 

pruning, veneer/lumber-grade recovery of and 1.0 tree height dimensions had 

individual trees can be improved, with a solar radiation reduced 21% and 17% in 

resulting value increase of pruned trees over and 71% and 30% in i0 years based on 

that of unpruned trees. However, in practice height and crown width increments of p

the landowner may not be rewarded for his trees in upland hardwoods.

pruni'ngcosts at the time of sale and harvest,

so the decision to prune, as with any

investment decision, must be carefully SgK_%Y

considered. REmember, pruning does not

increase the growth rate of the tree! Only The management of black walnut in 

the reduction of surrounding competition stands is basically the combinat

• improves individual tree growth. Pruning is strategies normally employed in m

simply a cultural treatment that should natural stands and the intensive 

increase the potential stumpage value of a practices developed for plantations. 

tree. dual strategies, if carefully thought 

• the planning process and then implemen

• Planting in Natural Stands result in the successful regeneration

and development of black walnut t

Natural woodlands usually contain natural woodlands.

relatively few black walnut trees. Yet, many

woodland sites are capable of growing black

walnut. Since the natural regeneration of LITERATJRE CITED

black walnut is a slow and "chancy" process, Beineke, W. F. 1977. Corrective pru

• many woodland owners wish to "sweeten" the mix black walnut for timber form. Purd

by planting black walnut trees after removing Coop. Ext. Serv. Publ. FNR-76, 5 p.

residual trees in a regeneration cutting. Fischer, B. C. 1979. Managing light 

selection method, p. 43-53

Clearcutting or at least the creation of Regenerating oaks in upland 

large openings (areas larger than 2-4 tree forests. Proceedings of the 1979 

heights in diameter) is recuR,ended as the Wright Forestry Conference, 

best site preparation method prior to planting University, West Lafayette, Indian

black walnut in a woodland. Such cutting p.

creates an area large enough that open Hilt, D. E. 1977. Introduction o

conditions are created. This is essential for walnut and northern red oak seedlin

black walnut. Following the planting of black upland hardwood forest in sout

walnut, the real management begins. Studies Ohio. U.S.D.A. For. Serv. Res

(Krajick 1975; Hilt 1977) and field experience NE-241, 5 p.

, continue to demonstrate that cultural Hilt, D. E. 1979. Diameter growth o

treatments to control the cumpeting dense oaks after thinning. U.S.D.A. Fo

' sprout, shrub and herbaceous cover on Res. Pap. NB-437, 12 P.

previously forested sites is required if Krajicek, J. E. 1975. Planted blac

significant numbers of planted black walnut does well on cleared forest sit

trees are to survive and grow to a dominant competition is controlled. U.S.D

' Serv. Res. Note NC-192, 4 p.

Phares, R. E. and R. D. Williams. 

• Crown release promotes faster 

. growth of pole-size black walnut. 

• 3personal communication with Dr. Harvey For. Serv. Res. Note NC-124, 4 p.

A. Holt, Associate Professor of Forestry,

Purdue University.
°

. •

Schlesinger, _R. C. and D. T. Funk. 1977.

Manager's handbook for black walnut.

U.S.D.A. For. SeEr. Gen. Tech. Rep. NC-38.

22 p.

Smith, H. C. 1979. Release of young

yellow-poplar and black cherry- I0 year

results. Southern J. of Appl. Forestry 3

(4) 161-164.

Tr'mble, Jr., G. R. and E. H. Tryon. 1979.

Silvicultural control of wild grapevines.

W. virginia Univ. Agr. and Forestry Expt.

Sta. Bull. 667, 19 p.

°

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96
GR3W]_ OF BLACK WALNUT IN A FEREILIZED _ION 1

J. M. Braun and W. R. Byrnes2

Abstract.--Height and D.B.H. growth has averaged 2.2 ft/yr

and 0.44 in/yr, respectively, for a well-managed, fertilized

walnut plantation located on a moderately fertile site.

Growth of the best 15% of the stand has averaged 2.7 ft/yr

and 0.54 in/yr for height and D.B.H., respectively. The

plantation was fertilized with N, P and K three times since

planting in 1968, and yearly measurements of height and

D.B.H. were made through 1977 and again in 1980. Statistical

analysis failed to detect any meaningful growth response

associated with fertilizer treatments, and there are no

significant trends displayed by the data. The evidence in

this study suggests that fertilizer amendments are not needed

during the establishment of black walnut plantations located

on good sites. This study is also discussed briefly as a

case history of the growth and management potential for a

walnut plantation.

_CTION Fertilization is another 

recognized as potentially significa

The intensive management of black walnut improving the growth of black walnut. 

_ L.) in natural stands and time this study was initiated, 1967, th

plantations is of concern to many people today very little information published rela

as an investment opportunity. Interest in field fertilization of black walnut. D

black Walnut has existed for many years due to study of the effects of fertilization i

the high stumpage prices that black walnut plantations was considered of pa

commands. The techniques needed to importance and interest. The purpose 

intensively manage black walnut, especially in study was to quantify the growth respo

plantations, have gradually developed during a young black walnut plantation to 

the last two decades. Improvement in rates of nitrogen, phosphorus, and po

management factors such as site selection and fertilization.

preparation, planting methods, spacing,

interplanting with various nurse and agronomic

crops, insect, disease, and weed control, L_ RKVIEW

corrective pruning, as well as the economic

.. aspects of walnut management have been Despite a broad base of experi

' researched and the results and r_dations forest fertilization in some parts 

widelydisseminated. Significant strides also world and in some regions of our 

, have been made in genetic improvement of black practical knowledge of field fertiliza

walnut, primarily through selection and black walnut is still fragmentary. Si

vegetative propagation. Finally, improved basic information on the nut

nursery management has produced higher quality requirements of black walnut is incump

' black walnut planting stock.

' Based on greenhouse experiment

black walnut, Hacskaylo et al. 

described visual nutrient deficiency s

normal leaf characteristics, and the 

ipaper presented at the 1981 Joint nutrient concentrations associated wi

Meeting of walnut Council/Northern Nut Growers condition. This basic informat

Association, W. Lafayette, Indiana, Aug. 9-14, particularly useful for validati

1981 condition of normal foliage. However

• "2Research Forester and Professor of site requirements of black walnut a

Forestry, respectively; Department of Forestry known, it is unlikely that 

and Natural Resources, Purdue University, West deficiencies severe enough to 

Lafayette, Indiana 47907. recognizable deficiency symptoms will 

L

j
a Well-located walnut plantation. If nutrient Plainfield sand; a droughty soil low in

deficiencies do occur they are more likely in organic matter. Three yearly surface

the range of "hidden hunger." In this applications of N at 2600 ib/A resulted in a

condition, nutrient deficiencies reduce gr_fch D.B.H. growth response of 254% after the third

but are not severe enough to produce year. The diameter growth rate of fertilized

distinctive visual symptums, trees amounted to 0.26 in/yr but returned to

the pre-treatment level of 0.07 in/yr within

Phares and Finn (1972) prepared a list of two years after the final fertilizer

tentative critical foliar nutrient levels for application. Treatment with a cumplete

black Walnut trees. Foliar levels below 2.00% fertilizer (N, P, and K) improved diameter

N, 0.10% P, and 0.75% K were classed as gr(_ch only 180% during the same period.

deficient for these elements, with the strong

likelyhcod of a growth response to nutrient Yon Althen (1976a) thinned and fertilized

applications. Intermediate values, where a 27-year-old plantation of black walnut

fertilizer may. or may not ellicit a response growing on former agricultural land in

were give_ as 2.00-2.60% N, 0.10-0.25% P, and Ontario, Canada. A complete fertilizer was

0-.75-1.30%K. Presentation of these critical applied at rates of 450-218-200 ib/A of N-P-K,

values is a odefinite step in the right respectively. Foliar N and P increased while

direction, but to our knuwledge these data K concentrations decreased 1-year after

have not received extensive field testing, trea_nent. By the end of the third growing

season, f01iar nutrient concentrations

The feasibility of fertilizing black returned to pre-fertilization levels. The

walnut at the time of planting appears to be trea_nent had negligible effect on trees of

related to the suitability of the site for average basal area. Huwever, considering only

walnut. Ponder (1980) studied walnut on the largest 100 trees/A (the probable future

Wakeland silt loam, a somewhat poorly drained crop trees), fertilization increased the

soil, that was a marginal site for walnut, average diameter and height by 27% and 22%,

:Fertilization at tlme-of-planting stimulated respectively.

both: height and diameter growth of the trees.

Huwever, growth did not equal that of black Maeglin et al. (1977) fertilized two 40

walnut planted on good sites. Other studies year old stands of black walnut to ascertain

on sites suitable for walnut (Byrnes 1966, the effects of nitrogen fertilizer on growth

Schneider et al. 1970, and Williams 1974) have and log quality. They concluded high

tested a Wide range of planting methods, and fertility bottunland sites should not be

weed control techniques in conjunction with fertilized as the control trees grew more then

various fertilization treatments at those fertilized. On upland sites

t'me-of-plantlng. _he consensus opinion is fertilization increased diameter growth, but

that walnut seedlings planted on good sites do not to a statistically significant degree. It

not exhibit significant or practical growth was noted that log quality of unfertilized

responses to fertilization at trees on the upland site suffered due to

time-of-planting, therefore, fertilization was sprouting along the lower bole. This

not r_ at this stage. Williams sprouting may have been suppressed by the

(1974) reported that fertilization reduced fertilization which would result in a

survival andgrowth of the planted seedlings, significant increase in the quality of those

In this case, seedling roots probably were stems.

bur_ by fertilizer salts placed in the

• planting hole (I ounce 8-32-8/tree). It was

also apparent however that competing weeds ME_fX_

stimulated by the fertilizer suppressed some

walnut seedlings. This study was located on the Martell

Experimental Forest of Purdue University about

The Managers Handbook for Black Walnut 10 miles west of West Lafayette in Tippecanoe

(Schlesinger and Funk 1977) states that County, Indiana. 'J:he soil type is Genesee

fertilization of pole-size trees is likely to silt loam (Fluventic Eutrochrept), a deep,

provide the best economic returns, neutral to slightly alkaline, wall drained

Schlesinger and Funk also caution, huwever, soil derived fram stratified loamy and silty

that "not much is yet known about alluvium washed from uplan_ areas of Wisconsin

fertilization," and "It is not possible to glacial till. The site is nearly level and

make specific recommendations for specific occupies a second terrace of the Wabash River.

soils at the present time . . ." The S.C.S. soil interpretation record for

Genesee silt loam indicates that black walnut

Neely et al. (1970) examined a is suitable for planting. Other site

22-year-old walnut plantation growing on selection criteria (Carmean 1966, Losche

98
1973aJ also indicate that this soil/site was vegetation. Chemical methods of weed con

suitable for black walnut. _he area had a were not used due to possible interact

past history of agricultural cropping and with the ferili_.ertreatments.

grazing, but had lain fallow for several years

prior to the initiation of this study. !

• ! _I_

In early April 1968, 1-0 seedlings frum _ / / \

the Indiana state nursery were planted in \\

• augered holes on an 8 by 8-foot spacing. _he 

seedlings were subjected to a severe late

frost in early May 1968, therefore, initial

fertilizer application was delayed until the

following year. Twenty-three fertilizer

treatments composed of various combinations of

N-P-K were applied in Spring 1969 (Table 1).

NUtrient elements were applied in the

following forms- N as ammonium nitrate, P as

triple superphosphate, and K as mutriate of

potash. _he 23 selected treatments comprise

an incu,plete factorial experiment in a triple

cube design with four replications. Each axis

Of the cube can be considered to represent one

of the applied nutrient elements, i.e. N, P,

or K and the amount of that element applied

indicates a point along that axis. This ""

particular design, proposed by Iowa State '_-

University statisticians, was utilized because _\

it gives good estimates of the linear and

• quadratic coefficients of the main effects

i.e. N, P, or K response as well as the

interaction between these elements.

At the time of planting, every other tree

in each row and column of the plantation was

designated as a buffer tree. Buffer trees

remained untreated, and served to isolate the

treated trees and to minimize the possibility

of fertilizer movement between trees treated

differently. The buffer trees were cut in

January 1973, resulting in the current

plantation spacing of 16 by 16-feet (fig. 1).

Repeat fertilizer treatments were applied

• during spring 1971 and spring 1975. The

fertilizer was surface-broadcast on an 8 by

8-foot square plot (64 sq. ft.) centered on Figure l.--Fertilized black walnut planta

each trea_ent tree. Each fertilizer located at Purdue University, Mar

treatment was applied to four trees within a Forest: A Block 1, Dec. 1972, 8 x 8-

block (replicate). spacing; B Block 2, March 1981, 1

16-foot spacing.

This plantation has been intensively

managed throughout its life. Prompted by the

severe freeze in 1968, the plantation received

frost protection during the spring of 1970 and

1971. This was accomplished by igniting Corrective pruning to improve stem 

petroleum-coke bricks on nights that damaging has been applied periodically since 1

frosts were anticipated. This provided a low Stem pruning also was initiated in 197

smoke cover and reduced back radiation from encourage development of clear bole wood. 

the soil. The treatment was successful in plantation has not been irrigated at any 

minimizing frost damage, and no pesticides have been used for insec

disease control. Some top breakage of t

Mechanical cultivation several times each has occurred periodically during se

s_mer has been used to control cumpeting storms.

0 
.

Table l.--Mean!I/survival, height, diameter-at-breast height (DBH), and total

volume of black walnut by fertilizer treatment in fall 1980.

Fertilizer Applied Survival • Total Height D.B.H. Total2 ,

N ' P K Volume_/

(ibs./A) " (%) (ft.) (in.) " (cu."ft.)

0 0 0 94 26.2 5.4 2.1

•0 0 140 94 28.5 5.9 2.6

0 60 0 i00 29.9 5.7 2.4

0 60 140 i00 31.2 6.3 3.0

400 0 0 i00 29.9 5.9 2.6

400 0 0 i00 28.5 5.6 2.4

400 60 0 i00 28.5 5.7 2.4

400 60 140 94 29.9 6.2 2.8

200 30 70 i00 28.9 5.7 2.4

0 30 70 i00 26.2 5.5 2.2

400 30 70 87 ' 27.9 5.8 2.4

200 0 70 100 31.5 6.0 2.7

200 60 70 . 94 25.6 4.9 i.7

200 30 0 i00 32.5 6.1 3.0

200 30 140 i00 28.9 5.6 2.4

i00 15 35 I00 30.8 5.9 2.7

300 45 105 I00 28.5 6.1 2.7

I00 15 105 i00 32.2 6.3 3.0

300 45 35 i00 26.9 5.6 2.2

300 15 35 I00 27.9 5.7 2.4

• i00 45 35 i00 31.8 6.3 3.0

i00 45 105 i00 25.6 5.2 i.9

300 15 105 i00 27.2 5.5 2.2

All treatm , ents , , J.98, 28.9 5.8 , , ,2.5

1/Mean of four replicaticns 

• 2--/Fcumn_aefrom Tcdhunter et al. (1979)

V =-2.86094 + 0.14366 _D 2 x H) + 400

where: V = total sten volume in cubic feet

D = DBH in inches

H = total height in feet

Soil samples were collected before the RESETS AND DISCUSSION

first fertilizer application in 1969, in 1970,

and again pEiOr to fertilization in 1975. Data on total height and D.B.H. of the

These samples were analyzed for available P fertilized trees was subjected to statistical

and exchangeable K.° In addition, the 197_ analysis at the P=0.05 level. The individual

samples were tested for KCI extractable NH- linear and quadratic effects for the three

and N0_. All tests were made by the soi_ nutrient elements as well as their

testing_ laboratory at Purdue University. interactions were isolated by use of multiple

regression. Not a single instance of a

The total height and D.B.H. of all statistically significant growth response

fertilized trees were measured in the fall related to fertilizer treatment of black

each year through 1977 and in 1980. The walnut was detected on these soil and site

growth response of the four trees comprising conditions.

an experimental unit was averaged and

represents the treatment response for a given In a similar analysis, year-by-year

block, height and D.B.H. growth was examined. In

100 •
fall 1975, the year of the last fertilizer group of four treated trees within a b

application, a significant height growth whereas a cumplete factorial design would 

response was noted for N and K (P=0.05). required 500 treatment units. Although 

However, these responses were not of a design is widely used for indus

practical magnitude, and there was no applications, the large variation inhere

carryover into subsequent growing seasons, biological systems reduces the ability of 

design to detect treatment differen

Table 1 displays results of the fall 1980 Thus, although treatment differences 

measurements by fertilizer treatment. For all actually exist, they are of such a 

fertilizer levels and blocks combined, the magnitude that they cannot be separated 

average values for height, D.B.H., and volume the natural variation in growth of 

are 28.9 feet, 5.8 inches, and 2.5 cubic feet, plantation.

respectively. It is evident that there is a

wide range of values about these means, and The main objective of this study 

there is no apparent relationship between the realized by concluding that fertilizatio

measured values and the applied fertilizer, young black walnut stands, less 

Survival was excellent, ranging from 87 to i00 13-years-old, planted on a good walnut 

percent among fertilizer levels, with a mean will not yield a growth response at ferti

of 98 percent for all treatments and levels used in this study. In addition, 

replicates combined, study provides the basis for an excellent 

historY of tree growth in a well ma

There are several reasons why we believe walnut plantation.

the walnut plantation in this study did not

respond to fertilization. Most importantly, Figure 2 shows the total height 

the fertilizer added during this study D.B.H. over the life of the plantation, 

amounted to only a fraction of the available to 1980. For both height and D.B.H., a ra

nutrients on this fertile site. Analysis of

surface samples collected in 1969 prior to the

• first fertilizer application indicated 54 and

168 ib/A of available P and exchangeable K, 35_

respectively. In 1970 the total soil profile

was

i.e.

analyzed

no fertil

f

izer

rom

ad

one

ded

of

. The

the

ava

con

i

t

lab

rol

le

pl

P

o

a

t

nd

s,

3o.L o Toto_ig, l t

exchangeable K in the whole profile amounted : o O BH

to 355 Ib/A and 960 ]b/A, respectively. Table 25 "-

2 presents the results of soil analysis from --

samples taken in the spring of 1975 prior to

the third fertilization. Previous fertilizer _ 2oadditions had not materially increased the zt9 

supply of available soil nutrients for any

element (P=.05). Consequently, if z 15 - 

fertilization cannot measurably alter the " 

site, it cannot be expected to measurably _ •

influence the growth of vegetation on that _o io- 

" " site. 

5- 

• Secondly, as stated above, soil analysis ' 

indicated that the native site was moderately :

to highly fertile. Thus, despite the high 09ee 19m 1972 1974 i976 1978 _9

nutrient demands that black walnut makes on a YEAR

planting site, the site was capable of

supplying these needs. The best evidence for

this is the fact that the growth of the Figure 2.--Mean total height and D

control trees has not differed significantly (diameter-at-breast-height) for ferti

(P=0.05) from trees treated with any of the black walnut by year for the p

fertilizer combinations (Table 2). 1968-1980, at Purdue Martell Forest.

Finally, there is a statistical

explanation why grouch differences were not

found. The triple cube design allowed

exaaination of all the individual factors of Ipersonal cummunication with Dr. V

interest, and their interactions. This was Anderson, Professor of Statistics, P

accumplished with only 95 treatment units (a University.
Table 2.--Soil N, P, and K, and current height, DBH, and total volume

by increasing levels of applied nutrient.

SoiiI/ Fall 1980

Fertilizer Analysis Total

_Applied Sprin_ 1975 Height D.B.H. Volume

_./A _./A ' ft. ' _. _." f_.

Ni_cx:jen

0 119 28.5 5.7 2.5

100 131 30.2 5.9 2.6

200 127 29.5 5.7 2.4

300 117 27.6 5.7 2.4

400 136 28.9 5.8 2.5

Phosphorus

0 76 28.9 5.7 2.5

15 79 ' 29.5 5.8 2.6

30 91 28.9 5.7 2.5

45 91 28.2 5.7 2.5

60 96 28.2 5.7 2.5

Potassium

0 194 29.5 5.7 2.5

35 216 29.5 5.9 2.6

70 222 27.9 5.5 2.3

105 224 28.2 5.7 2.4

140 232 29.5 5.9 2.6 ,

i/Available N and P and ex_eable K, for surface samples

25-

A 

• E2o- I

>-

relatively uniform growth rate has been _z =s- I 1

growth,rates over the 13-year peziod have been •_ 5-

2.2 ft/yr and 0.44 in/yr fOE total height and _

D.B.H., respectively. All seedlings attained _ ---J •

the D,B.H. height (4.5 feet above the ground) <18 18-2121-2424-27_-3030-3333-3636-39>39

by 1970. _he vertical bars in figure 2 HEIGHT CLASS (ft.)

represent + 1 standard deviation about the

mean;-it is evident that this variation _s e t '

increased as the trees grew older. _ 3o

'J_be distribution in total height and _25

•D.B.H. by 3-foot height and 1-1nch D.B.H. )-

classes, respectively, for all plantation _ 20

•trees in _all 1980 is sha_n in figure 3. Over '" 15

75% of the trees currently exceed 27 feet in o

height, and about one-third of the stand is ,.,IO

tiandi llercates thathat n 33 Ofveet. er 50%Dioafmethtere trdiestresibutio havean _ 5 . ]. I

D.B.H. greater than 6 inches. _3 3-4 4-5 5-6 6-7 7-8 >8

D.B.H. CLASS (in.)

In an effort to judge how well the

Martell plantation was gr_ing, growth data

from several sources was assembled for Figure 3.--Total height and D.B.H. distribuumnParison (Table 3). _he sources listed tion in fall 1980 for fertilized black walrepresent a wide range of soil and climatic nut plantation at Purdue Martell Forest.

1Q2
° ,

- 

,

..... Ill _ _ ; _III IIIII I...... IIi I _ - _LI IIII I I _ I / _ _ _
conditions, stand origin, treatments, and Losche, C. K. 1973b. Black walnut growth

intensity of management. Efforts were made to better on deep, well-drained bottumland

find and include references reporting fast soil. U.S.D.A. For. Serv. Res. Note

growth rates. It is evident that the NC-154, 3p.

fertilized walnut plantation studied here is Maeglin, R. R., H. Hallock, F. Freese, and K.

growing as well as the best walnut trees A. McDonald. 1977. Effect of nitrogen

studied elsewhere. Given the intensive fertilization on black walnut--growth, log

management this plantation has received, we quality, and wood anatumI. U.S.D.A. For.

believe the unimproved stock used in this Serv. Res. Paper FPL-294, 13p.

study has gr_ at a rate close to the maximum Neely, D., E. B. Himelick, and W. P_ Crowley,

potential rateachievable on this site. Jr. 1970. Fertilization of established

trees: A report of field studies.

Illinois Nat. Hist. Survey Bull.

Literature Cited 30(4)-235-266.

Phares, R. E. 1973. Managing immature trees

Bey, C. F. 1980. Growth gains frum moving for more high-quality logs and related

blauk walnut provenances northward. J. products, p. 49-54. In Black walnut as a

For. 78:640-645. crop. U.S.D.A. For. Serv. Gen. Tech. Rep.

Brinkman, K. A. 1966. Growth and yield 'on NC-4.

• prairie soils, p. 50-52. In Black walnut Phares, R. E. and R. F. Finn. 1972. Using

culture. U.S.D.A.N. Cent. For. Exp. Sta., foliar analysis to help diagnose nutrient

! St. Paul, Minn. deficiencies in black walnut. N. Nut

i Byrnes, W. R. 1966. Site preparation and Gr_ers Assoc. Ann. Rep. 62:98-104.

weed control, p. 20-27. In Black walnut Ponder, F., Jr. 1980. Fertilization improves

culture. U.S.D.A.N. Cent. For. Exp. Sta., black walnut growth on a poorly drained

St. Paul, Minn. site. Tree Planters Notes 31(4):17-19.

Byrnes, W. I_, J. E. Krajicek and J. I_ Sc211esinger, I_ C. and D. T. Funk. 1977.

_ Wichman. 1973. Weed control, p. 42-48. Manager's handbook for black walnut.

In Black walnut as a crop. U.S.D.A. For. U.S.D.A. For. Serv. Gen. Tech. Pep. NC-38,

Serv. Gem. Tech. Pep. NC-4. 22p.

Carmean, W. H. 1966. Soil and water Sc2meider, G., G. Khattak, and J. N. Bright.

requirements, p. 32-34. In Black walnut 1970. Modifying sites for the

culture. U.S.D.A.N. Cent. For. Exp. Sta., establishment of black walnut, p. 155-169.

St. Paul, Minn. In Youngberg, C. T. and C. B. Davey, ed.

Clark, P. M. and R. D. Williams. 1979. Black Tree growth and forest soils. Oregon State 

walnut growth increased when interplanted Univ. Press, Corvallis, Oregon.

with nitrogen-fixing shrubs and trees. Toflhunter, M. N., S. E. McKeand, and W. F.

Indiana Acad. of Science 88-88-91. Beineke. 1979. A volume equation fOE

Funk, D. T., R. C. Schlesinger and F. Ponder, seedling and sapling black walnut. "Purdue

Jr. 1979. Autumn-olive as a nurse plant Univ., Ag. Exp. Sta. Bull. 197. 3p.

for black walnut. Bot. Gaz. yon Althen, P.W. 1976a. Ten-year results of

140(Supplement)-5110-5114. thinning and fertilizing of a pole-sized

Hacskaylo, J., R_ F. Finn, and J. P. black walnut plantation. Canadian For.

Vimmerstedt. 1969. Deficiency symptums of Serv. Great Lakes For. Res. Ctr. Pap.

same forest trees. Ohio AgE. Res. and O-X-245, 17p.

Devel. Ctr. Res. Bull. 1015, 68p. yon Althen, F. W. 1976b. Effects of site

Heflin, E. L. 1965. Black walnut plantation preparation and post-planting weed control

88 Years old. •J. For. 63:700-701. on the survival and height gr_,T/_ of

• Krajicek, J. E. 1975. Planted black walnut planted hardwood seedlings. Canadian For.

does well on cleared forest sites--if Serv. Great Lakes FOr. Res. Ctr. Rep.

' competition is controlled. U.S.D.A. For. O-X-248, 15p.

Serv.Res. Note NC-192, 4p. Williams, I_ D. 1974. Planting methods and

KrajiCek, J. E. and R. D. Williams. 1971. treatments for black walnut seedlings.

Continuing weed control benefits young U.S.D.A. For. Serv. Res. Paper NC-107, 5p.

planted black walnut. U.S.D.A. For. SeEr.

Res. Note NC-122, 3p.

Losche, C. K. 1973a. Selecting the best

available soils, p. 33-35. In Black

walnut as a crop. U.S.D.A. For. Serv. Gen.

' Tech, Pep. NC-4.

104.
INTERACTION OF NITROGEN FERTILIZATION AND CHEMICAL WEED CONTROL

• ON FOUR-YEAR VOLUME GROWTH OF A BLACK WALNUT PLANTATION 1

P. E. Pope, H. A. Holt, and W. R. Chaney 2

Abstract.--Four year height, diameter and volume growth

of a 16-year-old (treated at age 12) black walnut (_

nlgra L.) plantation was significantly influenced by Nfertilization and chemical weed control. The greatest

four year cumulative diameter increment (1.75 in.) and

total volume growth .568 cu. ft.) occurred on trees

fertilized wi£h i00 ibs. nitrogen per acre in combination

with weed control. Weed control alone resulted in a 38%

increase in volume growth above untreated trees after four

years whereas weed control in conjunction with I00 ibs.

nitrogen per acre produced a 121% increase in volume growth.

Changes in foliar nitrogen levels corresponded closely with

changes in volume growth.

LNTRODUCTION planting. The intent of this research w

ascertain the growth response to nitrogen

Both private and industrial woodland fertilization and weed control of establ

owners have shown increasing interest in plantation grown black walnut trees.

planting and growing black walnut (Juglans

nigra L.). Expectations of high return on

investment are certainly a stimulus for this METHODS

activity. Cultural techniques to hasten

• growth and shorten rotation are of potential The study was established in a 12-y

value. Considerable research has been done old black walnut plantation planted in .

on genetic improvement, spacing and planting County, Indiana in the spring of 1965. 

methods, weed control, pruning, and fertiliza- trees were planted at ii x Ii ft. spacin

tion, but many questions still remain (Bey a Martinsville silt loam soil (Typic Hap

and Williams, 1976; Dickson, 1971; Holt dalfs, fine-loamy, mixed, mesic). A co_

and Voeller, 1975; KraJicek, 1971, 1975; tion of nitrogen fertilization and/or ch

• " Krajicek and Williams, 1971; Schlesinger and weed control was applied to one-half of 

Funk, 1977; and Williams, 1974). This paper plantation on May 20 and 21, 1977. The

reports a study of the effect of nitrogen experiment was arranged in a split plot 

fertilization and chemical weed control on three replications of each treatment and

growth of 12-year-old black walnut trees for unequal observations per replication. 

three years after treatment. Most studies on were analyzed by analysis of variance (

fertilization have dealt with the response and Duncan's new multiple range test. N

of trees to nutrients applied at the time of treatments constituted the whole plot (

acres) and chemical weed control was app

in 4 ft. bands down either side of the p

rows to one-half of each fertilized plot 

acres). Nitrogen as urea was broadcast 

Ipaper presented at the 1981 Walnut hand at rates equivalent to 0, 50, or !

Council Meeting--Symposium, Purdue University, of elemental nitrogen/acre. Weed contro

West Lafayette, Indiana, Aug. 9-14, 1981 • - " treatments were none and a combination o

2Authors are Assistant, Associate and glyphosate [N-(phosphonomethyl)glTclne] 

Professor, Department of Forestry and Natural simazine [2-chloro-4,6-bis(ethylamln°)-SResources, Purdue University, West Lafayette, triazine], each at 4 lb. ai/A in water. 

Indiana 47907. allow for border trees, 18 trees were =e
in each replication of no weed control treat- than those that received the same rate of

ments whereas 12 trees were measured in each nitrogen fertilization but no chemical weed

replication of weed control treatments. On control, although statlstically significant

May 1, 1977, prior to treatment application, differences at u = 0.05 were evident in only

trees averaged 20 ft. in height and 3.5 in. two of the treatment comblnatlons. The greatdiameter at 4.5 ft. above the _round and had est increase in diameter growth occurred on

a per acre volume of 283.53 ft °. Total trees fertilized with 100 lbs. nltrogen/acre

height and diameter measurements were taken with chemical weed control. These trees

after the growing season for each of four years increased in diameter 0.82 in. more than the

following treatment. These parameters were unfertilized trees with no weed control. For

used to compute volume in cubic feet and trees receiving no chemical weed control,

expressed on a per acre basis w-Ith 360 trees fertilization with urea at 100 lbs/acre

per acre. Volume computation utilized an resulted in more diameter growth than attained

equation developed for seedling and saDlln_ by trees not fertillzed or those receiving 50

black walnut; V =-2.86094 + 0.14366 CDZH+400, ibs. nitrogen/acre. The differences were

where V = total stem volume in cubic feet, D = greatest for the 1980 growing season and the

diameter at 4.5 ft. in inches, and H = helght, four year growth accumulation. Approximately

i in feet (Todhunter, et al., 1979). 50 to 65 percent of the radial increment growth

i in all treatments, including the control,

Foliage samples were collected and occurred in 1979 and 80, three and four years

i analyzed for nitrogen by micro-kJeldahl after treatment with 32-42 percent occurring

i distillation (Wilde, et al., 1972) prior to during the wet 1979 growing season.

treatment and in mid-September for two years

• following treatment. The data for 1980 are difficult to inter-

: pret. The diameter growth data suggest a

decline in the rate of incremental growth,

RESULTS however, the severe drought during the 1980

i growing season could have limited the growth

_ Average annual diameter increments and that would have been attained under more normal

total diameter increment over 4 years are conditions.

! shown in Table i. Except for the 1979 growing

season, weed control alone, without nitrogen Chemical weed control alone did not affect

fertilization, did not affect diameter growth, the height growth increment of the 12-year-old

Likewise, the total diameter increment for the (presently 16-year-old) black walnut trees

four year measurement period was not slgnifl- (Table 2) nor did nitrogen fertilization in the 

! cahtly greater than no weed control. Weed absence of weed control. Trees that received

control in conjunction with nitrogen fertill- i00 ibs. nitrogen/acre and chemical weed

zatlon did result in greater diameter growth control had a significantly greater height

over the four year measurement period. Except growth increment in 1977, 1980 and in cumulafor the 1980 growing season, trees that tlve growth for the four-year period than trees

received nitrogen and weed control grew more in plots with no fertilizer or weed control.

•

•

Table l .--Influence of N-fertillzation and chemical weed control on the

. diameter growth increment of a black walnut plantation.

Fertilizer Diameter Increment (in.)

Rate Weed ............. Year .................

_(Ibs N/A) Control '77 '78 '79 '80 Total

0 No 0.21a I/ 0.20a 0.34a 0.18a 0.93a

Yes 0.21a 0.33ab 0.555 0.20a 1.29ab

50 No 0.25a 0.18a 0.48ab 0.33b 1.24ab

Yes 0.34b 0.38b 0.5 lab 0.28ab 1.5 lb

100 No 0.32ab 0.30ab 0.61b 0.49c 1.72c

, Yes, 0.36b , 0.37. b , 0.63b. 0.39b. .... 1.75c

i/Column values not followed by the same letter are significantly different (Duncan's New Multiple Range Test, u = 0.05).

-

106
°

°

Table 2.--Effect of N fertilization and chemical weed control on

annual incremental height growth of black walnut.

Fertilizer . Height Increment (ft.) _

Rate Need .-Year............

(ibs N/A) Control '77 '78 '79 '80 Total

0 No 2.2a l/ 0.8a 2.0a 1.3a 6.6a

Yes 2.8a 0.8a 3.4ab 0.9a 7.9a

50 No 3.0a 1.3a 1.4a 2.8ab 8 .Sab

Yes 2.9a 2.0a 2.6ab 3.6b ll.10ab

100 No . 3.2ab 1.4a 4.3b 2.9ab ll.80ab

Yes 4 .Sb 2.1a 3o8ab 3.1b 13.50b

/

l_olumn values not'followed by the same letter are slgnlflcantly

different (Duncan's New Multiple Range Test, a = 0.05).

Volume increase of black walnut per acre Increased growth response in the high n

during the four-year study period, llke height weed control treatment relatlve to high 

and diameter growth, was unaffected by weed gen and no weed control was llmlted to 

control alone (Table 3). Generally, per acre first growing season following treatment

volume increment increased with increasing increased height and diameter growth co

• levels of nitrogen fertilization and weed with the multlpllcatlve characteristic 

control. Fertillzatlon at 50 ibs. nitrogen/ volume calculations accounted for the i

acre with weed control or fertilization at i00 volume of wood produced.

lbs. nltrogen/acre with or without weed control

significantly increased volume growth over that No differences in percent follar n

of untreated trees. The largest volume were evident in leaves collected on May 

increment during the four-year study period 1977, prior to treatment application (T

occurred on trees that received chemical weed At the end of the first growing season,

control and i00 ibs. nltrOgen/acre. This September 1977, increased follar nitroge

treatment resulted in an additional 311 ft3/ found in response to both weed control 

acre when compared to the control treatment nitrogen application. Weed control alo

receiving no fertillzer or weed control, resulted in increased follar nitrogen i

Table 3.--Effect of weed control and nitrogen fertillzatlon applled in a 12-

year-old black walnut plantation on annual and cumulative volume growth.

Fertilizer Per Acre Volume Increment (ft _)

• Rate Weed ............. -Year ....... ,...........

(lbs N/A) Control '77 '78 '79 '80 Total

i

0 No 60.28a I/ 39.87a 78.50a 78.28a 256.93a

Yes 68.30a 59.85ab 134.46b 91.89a 354.49ab

50 No 77.57ab 43.52a 97.3lab 142.74b 361.14ab

Yes 91.20b 85.02b ll0.41ab 169.89b 456.52b

• 100 No 92.02b 63.64ab 158.88c 212.51c 527.05c

• .......... Yes I17.01c , 84.82b JJ , ,, 154.76c 211.31c __4 567.90c-- --

-L/Column values not followed by the same letter are slgnlflcantly different

(Duncan's New Multiple Range Test, a - 0.05).

?
Table 4.--Percent foliar nitrogen in black increases in tree follar nitrogen levels.

walnut in relation to nitrogen fertilization Nitrogen application increased follar nitrogen

and weed control, levels above that of unfertilized trees around

which weeds were controlled only when done in

conjunction with weed control. Fertillzation

Fertilizer without weed control was no more effective

Rate Weed ....... Date ......... than weed control alone at the end of the first

(ibs N/A) Control May '77 Sept• '77 Sept. '78 growing season• The benefits of 50 ibs.

nltrogen/acre and weed control were lost in the

0 No 2.36a I/ 2.26a 2.48a second year after treatment. This was due to

Yes 2.51a 2.o59b 2.85b the reestablishment of competing weeds on the

weed control plots in the second year. On the

50 No 2.63a 2.66bc 2.915 plots that received 100 lbs. nltrogen/acre,

Yes 2.58a 2.95c 3.42bc luxuriant amounts of nitrogen were apparently

still available for both weeds and trees during

! i00 No 2.41a 2.495 3.46_c the second growing season.

, Yes 2.53a 2.84c 3.61c

! The increased levels of follar nitrogen

} I/Column values not followed by the same letter in response to treatments relate closely to

i are significantly different (Duncan's New the volume growth increments that were found.

i Multiple Range Test, P < .05). These results the Russell

support suggestion by

(1961) that nitrogen generally affects leaf

i area of plants and that over a considerable

' range of nitrogen supply the amount of leaf

I the first and second years after treatment.

i When 50 ibs. nltrogen/acre were added in

area available for photosynthesis in proporconjunction with weed control, the levels of tional to the nitrogen applied. Ellis and yon

i Althen (1973) who worked with 30 to 85-yeari foilar nitrogen were greater than that of old natural stands of several hardwood trees

leaves of control trees at the end of the

first season. When compared to the weed in southern Ontario also concluded that nitroi Control only treatment, weed control applied genous fertilizer increased diameter growth

with 50 .ibs. nltrogen/acre did not slgnlfi- through increased leaf area.

cantly increase follar nitrogen levels in

September, 1978. At the end of the first Nitrogen fertilization of established

growing season, i00 ibs• nltrogen/a_re with trees does not always produce increased

| weed control resulted in levels of follar growth. A 40-year-old stand of black walnut

nitrogen that were much higher than control in southern Wisconsin on an upland site did

trees and this difference existed for two not show a significant increase in diameter

years after application, growth when fertilized with 500 lbs/acre of

elemental nitrogen as ammonium nitrate The

same rate of nitrogen application on a fertile

bottomland site reduced the rate of diameter

DISCUSSION growth below that of unfertilized trees

" (Maeglln, et al., 1977). Phares 2 (unpublished

Black walnut growth response to nitrogen data) found a similar retardation of black

application was anticipated based on results walnut growth in Indiana. Trees of a 60 to

of Phares and Finn (1971). They predicted no 80-year-old stand growing on a fertile bottomprobable growth response of black walnut land site grew less when fertilized with

trees from adding nitrogen when follar level

• nitrogen than trees not fertilized. Nevertheis above 2.6 percent, some response at follar less, Schleslnger and Funk (1977) stated that

levels of 2.0 to 2.6 percent, and a likely fertilization of pole-slze trees is likely to

response at levels below 2.0 percent follar provide the best economic returns and that

nitrogen• Follar nitrogen levels for trees

in this study were in the high side of the nitrogen is the most promising nutrient to

medium range, about 2 4 to 2 6% (Table 4). apply. They suggested that it may be neces-

• " sary to refertilize approximately every 5 years

The first growing season after nitrogen

fertilizatlon_ nitrogen levels increased to- to maintain growth stimulation. They also

a point where no additional response was

expected except in those trees that did not

receive weed control. This study clearly

shows that weeds are very competitive sinks 2Robert E. Phares. USDA Forest Service, North

for available nitrogen. Weed control Central Forest Experiment Station, Carbondale,

treatments alone resulted in significant Illinois.

108
emphasize that fertillzation should be KraJicek, J. E. 1975. Planted black wal

considered a supplement to other cultural does well on cleared forest sites -- 

practices, and cannot be expected to compen- competition is controlled. USDA Fores

sate for other limiting factors such as light Service Res. Note, North Central For. 

and moisture. The results of the present Sta. No. NC-192.

study reinforce these observations since

nitrogen was found to significantly increase KraJlcek, J. E. and R. D. Williams. 1971

diameter, height, and volume growth of small Continuing weed control benefits young

pole-slze trees and was most effective when planted black walnut. USDA Forest Ser

done in combination with weed control. Res. Note, North Central For. Exp. Sta

NC-122.

CONCLUSIONS Maeglln, R. R., H. Hallock, F. Freese and 

McDonald. 1977. Effect of nitrogen 

For the specific conditions of this ization on black walnut - growth, log

study, significant increases in volume growth quality, and wood anatomy. USDA Fores

_ of a young black walnut plantation can be Service Research Paper, Forest Product

achieved by fertilizing with 100 lbs/acre Laboratory, No. FPL 294.

nitrogen. The largest volume inc£ease was

recorded for plantations fertilized with i00 Phares, R. E. and E. F. Finn. 1971. Usi

1b/acre N, plus weed control. While foliar analysis to help diagnose nutri

fertilizatlon with 50 1b/acre N and/or weed deficiencies in black walnut. 62nd An

control improve volume growth over the Rept. North. Nut Growers Assoc., Carbo

unfertilized control these growth differences 111., 98-104.

were not significantly different.

Russell, E. W. 1961. Soil conditions an

growth. J. Wiley and Sons, Inc., New 

ACKNOWLEDGEMENT 9th ed.

The authors would like to thank Pierson- Schlesinger, E. C. and D. T. Funk. 1977.

Hollowell Compauy whose cooperationmade this Manager's handbook for black walnut. 

study possible. For. Serv. Gen. Tech. Rep. NC-38, Nort

Cent. For. Exp. Stn., St. Paul, Minn.

LITERATURE CITED Todhunter, M. N., S. E. McKeand, and W. F

Belneke. 1979. A volume equation for

Bey, C. F. and R. D. Williams. 1976. Weed seedling and sapling black walnut. D

control in black walnut plantations. Forestry and Nat. Res., Agrlc. Expt. 

USDA Forest Service Research Note, North Purdue Univ., Sta. Bull. 179.

Central For. EXP. Sta. No. NC-203.

Wilde, S. A., G. K. Volgt, and J. G. Iyer

Dickson, R. E. 1971. The effects of soil 1972. Soil and plant analysis for tr

moisture, texture, and nutrient levels on culture. Oxford and IBH Publishing C

the growth of black walnut. USDA Forest New Delhi, India. p. 114-116.

Service Res. Pap., North Central For. Exp.

Sta. No. NC-66. Williams, R. D. 1974. Planting methods 

treatments for black walnut seedlings.

Ellis, R. C. and F. W. von Althen. 1973. USDA Forest Service Res. Paper, North

Fertilization of adult and Juvenile Central For. Exp. Sta., No. NC-107.

hardwoods in Ontario, pp. 174-186, IN

Proc. Syrup. Forest Fertilization, USDA

Forest Serv., N.E. Forest Expt. Sta. Gen.

Tech. Rep. NE-3.

Holt, H. A. and J. E. Voeller. 1975. Influence of weed control on growth and nut

production of black walnut. 66th Ann.

Rept. North. Nut Growers Assoc., 144-145.

Krajicek, J. E. 1971. Spacing and pruning

black walnut to produce both nuts and

lumber. 62nd Ann. Rept. North. Nut Growers

Assoc., 95-98.

.
EFFECTS OF SELECTED COVER CROPS ON THE GROWTH OF BLACK WALNUT

P. L. Roth and R. J. Mitchell

Abstract.--Thls study was initiated to investigate the

effects of selected cover crops on the growth of black

walnut (Juglaps_L.). The cover crops tested were:

Poa pratensls L., Lollummultiflorum L., Phleumpratense L.,

Festuca arundlnacea Schreb., Trlfollum repens L., Lespedeza

stipulacea Maxim., Melilotus offlclnalls (L.) Lam.,

Lespedeza cuneata Dumont Maxim. and a clean-cultlvated con-

°, * trol. Cover crops significantly affected the height and

caliper growth of black walnut throughout the study period.

i Black walnut grown in clean-cultlvated plots exhibited

superior height and diameter. Within cover crop treatments,

i the height and caliper growth of black walnut grbwnwlth

" Lespedeza cuneata was the greatest while walnut grown in

association with Festuca arundinacea showed the poorest

growth.

t

Additional Keywords.--Helght growth, caliper growth,

! cover crop, _ nlgra |

: INTRODUCTION walnut grown in association with selected

forage cover crops.

•Black walnut (Julans nigra L.) is the

most Valuable of native American woods.

Accelerated reduction in the growing stock EXPERIMENTAL METHODS

• of quality black walnut, coupled with increaslng demands placed upon the resource, Site Description

have resulted in escalatlng prices for both

logs and standing timber (Callahan and The experimental site was located at

Smith 1974). If this shortage of black the Forest Tree Improvement Center two miles

walnut lumber and veneer is to be allevi- west of Carbondale, Illlnols. The soil is

ated, methods oriented toward the intensive classified as a Hosmer Silt Loam, a light

management of this species must be investl- colored forest soil, developed from loessal

gated, parent material. The soil has a fragipan at

a depth of 0.6 m which restricts root depth

For continued good growth, walnut trees and the movement of air and water.

require deep, well drained, loamy soils

(Losche 1973). Such sites normally have the Cover Crop Establlshment

potential to produce agronomic crops such as

corn, soybeans and forage crops. Combining The cover crops consisted of: two short

the management of forage crops with black grasses, Kentucky bluegrass (Poa pratensls

walnut allows a landowner to produce short • L.) and annual ryegrass (Lollum multiflorum

term returns to supplement income, until nut L.); two tall grasses, timothy (Phleum

and woodcrops can be reallzed, pratense L.) and tall fescue (Festuca

arundinacea Schreb.); two short legumes,

A number of articles have suggested white clover (Trifollum repens L.) and comthat this type Of "multlcropplng" management mon lespedeza (Lespedeza officlnalis (L.)

is economically sound (Garrett et al. 1976, Lam.) and serlcea lespedeza (Lespedeza

Callahan and Smith 1974), although it is cuneata Dumont Maxim.). The control treatwarned that the data used for the economic ment was clean-cultlvated throughout the

analysis are "incomplete and slightly growing season. In the fall of 1973 the

t!

speculatlve (Callahan and Smith 1974). cover crops were hand sown at locally

This study was initiated to provide data recommended agronomic rates. In the spring

pertaining to the growth response of black of 1974 any areas that did not establish

-

. ._

110
were resown to establlsh 100Z cover of the RESULTS AND DISCUSSION

specific crop in each plot.

Cover Crop Assessment

Black Walnut Establishment

Species of cover crops varied grea

Seed for the study was collected in the in their ability to maintain themselves 

fall of 1973. Parent trees were located association with black walnut over the 

within a ten-mile radius of Carbondale, year study period. The degree of compa

Illinois. No standards of quality were set bility of the eight species to the mowi

for the parent trees; however, all trees treatment also varied (Table I). Kentu

were Judged to be of average quality as bluegrass and tall fescue were the gra

standing saw timber. Walnut seeds were that showed the greatest compatibility 

pregerminated and planted in the spring of black walnut. Kentucky bluegrass (a s

1974. Seeds were planted on 0.9 x 1.5 m grass) maintained itself substantially

initial spacing. At the end of the 1974 and better under the influence of the mowin

o 1979 growing season trees were removed for while all other crop species were less

root/shoot ratio determination so that final abundant in the mowed replications.

spacing was 1.8 x 1.5 m. , Apparently, the low growing morphology

resulted in a competitive advantage fo

Experimental Design Kentucky bluegrass when mowing occurred

Tall fescue maintained itself well in 

The plantation was established as a the mowed and the unmowed condition, a

spilt-split plot factorial design with ten the major invader in plots sowed to ot

replications. These replications were put crop species. Timothy and annual ryeg

in a series of five blocks. Each repllca- were essentially eliminated from the p

tlon was 28.7 m wide by 19.2 m long, and tion by stand age six. This may have 

contained nine randomly located treatments, due to the susceptibility to Juglone o

• The treatments were eight cover crop species inability to compete with the aggressiv

plus a control that was kept free of vege- rescue sod. Serlcea lespedeza was the 

tatlon through clean-cultlvatlon. Each legume that maintained itself well in 

treatment was 1.5 m wide by 19.2 m long. On unmowed plots. In the mowed plots it

five randomly selected replications (one per appeared to be more susceptible to com

block), the cover crops were mowed at three- tltlon, especlally from tall fescue. 

week intervals during the growing season, clover, white clover, and common lesped

On the remaining five replications, the were unable to maintain themselves thr

• cover crops were allowed to grow undis- the study period.

turbed.

Height and Caliper Growth

Data Collection

Significant differences in mean h

Height and caliper (10 cm above ground growth of black walnut trees associated 

llne) measurements were recorded at the end the various cover crop treatments were

of the 1974, 1978, and 1979 growing seasons, observed throughput the study (Table 2

In late June, 1979 a team of four investl- After the 1974 growing season black wa

Kators optically estimated the percent cover trees growing on the clean cultivated 

bY forage specles in each treatment, showed superior growth relative to the 

cover treatments. Differences in heig

Data Analysis black walnut among cover crop treatment

after the first growing season were sm

The data were analyzed to detect signl- although some trends may be discerned.

flcantdifferences by analysis of variance. Timothy, white clover, sweet clover, c

If significant differences were present, lespedeza and annual ryegrass tended t

Duncants Multiple Range Comparison test was pete less with black walnut than did s

' employed to perform multlple comparison lespedeza, Kentucky bluegrass and tall

among the treatments. The significance fescue. Differences in height growth 

level was set at alpha = 0.05 for all accentuated by the end of the 1978 gro

statistical tests, season, with trees grown in association 

annual rye exhibiting a slowing of hei

growth and black walnut grown in seric

lespedeza showing accelerated mean hei

development. This reduction in growth 

black walnut in annual ryegrass plots 

have been due to the failure of annual 

' 
Table l.--Cover crop percentage of relative cover in 1979, six years after seeding

Kentucky Annual

blue- rye- Tall White Sericea Sweet Common

Cover Crop grass grass Timothy rescue clover lespedeza clover lespedeza

Percentage of Relative Cover

KentUcky bluegrass 29.5 8.3 7.5 5.3 6.5 - 4.3 8.8

Annualryegrass - , .......

Timothy - 0.5 1.5 - - - 0.3 -

Tall fescue 44.5 51.6 63.0 70.0 72.3 5.3 49.0 57.0

White _61over - - - .....

Sericea lespedeza 1.7 - 0.5 7.5 1.8 87.0 2.0 1.0

Sweet clover ..... - - 8.0 3.0

Common lespedeza 1.5 - 70.5 0.3 1.5 - - -

Invadlngweedy

species 22.8 39.7 27.0 16.9 17.9 7.7 36.4 30.2

Kentucky bluegrass 53.6 9.3 9.8 14.5 4.8 8.2 15.5 8.8

Annual ryegrass ........

Timothy - 0.3 ......

Tall rescue 27.2 69.8 59.5 66.5 68.0 36.0 44.8 57.0

White clover - _ - I.0 - I.0 - - 3.0

Sericea lespedeza ..... 31.8 I0.0 1.0

Sweet clover ........

Common lespedeza - 1.5 2.3 0.8 3.0 0.5 5.5 -

Invading weedy

species 19.2 19.3 27.4 18.2 23.2 23.5 24.2 30.2

• Table 2.--Height and caliper growth of black walnut intercropped with eight

forage species and grown under clean cultivation

1974 1978 1979

Height Caliper Height Caliper Height Caliper

Cover Crop (cm) (mm) (cm) (mm) (cm) (mm)

• °

• "" I

Kentucky bluegrass 20.4 c 2.3 c 73.6 cd 14.5 cd 96.7 cd 21.1 b

Annual ryegrass 21.6 bc 2.3 c 74.2 c 12.4 d 83.5 d 15.8 c

Timothy 24.0 b 2.6 b 95.9 b 17.8 bc 115.4 bc 22.9 b

Tall rescue 20.2 c 2.2 c 63.7 d 10.6 d 81.4 d 15.8 c

White clover 22.6 bc 2.7 b 104.7 a 20.3 b 121.8 b 26.3 b

CommonJlespedeza 21.9 bc 2.3 c 102.0 b 17.9 bc 116.0 bc 23.8 b

Sweet clover 22.6 c 2.3 ¢ 102.8 b 19.0 bc 119.5 b 24.8 b

Sericea lespedeza 21.0 c 2.2 c 91.4 bc 17.2 bc 112.3 b 23.5 b

Control 30.7 a 3.9 a 123.2 a 26.0 a 148.2 a 35.2 a

IEach number followed by a common letter (a, b, c, d) is not significantly different at the

P = 0.05 confidence level.

. °

112
and the subsequent invasion of tall fescue seeding with sericea lespedeza. If t

observed in 1974. The clean cultivated plantation is subject to moderate to 

control outperformed all other treatments erosion potential the manager could k

during the 1978 and 1979 growing season, area (i m diameter minimum) around th

As a group, black walnut grown with sericea seedlings free of vegetation and seed 

lespedeza, white clover, sweet •clover, serlcea lespedeza at the time of plan

• common lespedeza and timothy treatments establishments. Tall fescue tended t

performed better than walnut grown with retard the growth of black walnut,

Kentucky bluegrass, annual ryegrass, and subsequently it is not recommended as 

tall fescue. The stunting of the growth of cover crop in black walnut plantations

black walnut when grown in association with during the early etablishment period.

rescue that was observed in this study., and

in a study by Todhunter and Beineke (1979), White clover and sweet clover we

may be due to competition for mineral able to compete with the invading tal

nutrients and water, or to an allelopathic fescue. Fertilization and liming to 

reaction. Walters and Gilmore (1976) found the fertility of the site to a more o

o _ that rescue suppressed the growth of sweet level may have resulted in the clovers 

gum(Liquidambar styraciflua L.) through an tablishing andmaintaining themselves,

allelopathic mechanism. _ although more research is necessary b

this species can be recommended for i

Mowing had no significant effect on cropping with black walnut.

height or diameter growth of black walnut.

Although mowing did affect the ability of

forage crops to maintain themselves through- LITERATURE CITED

out the study period (Table I).

Data presented in Table 2 on caliper Callahan, J. C. and R. P. Smith. 19

growth of black walnutshow relationships economic analysis of black walnut 

. similar to those observed in height growth, tlon enterprises. Purdue Universit

Clean cultivation resulted in superior cali- Research Bulletin No. 912, 19 pp.

per growth of black walnut throughout the

study. The caliper growth of walnut associ- Garrett, H. E., W. B. Kurtz, J. J. Al

ated With sericea lespedeza was initially C. Hype, J. E. Jones and G. S. Rut

retarded followed by a more rapid growth in 1976. Walnut multi-cropping manag

the later stages of the study. Caliper its biology an_ economics. Procee

growth of trees associated with fescue was Fifth North American Forest Biology

the lowest of the cover, crop treatments. Workshop.

Biological and Managerial Considerations Losche, C. K. 1973. Selecting the b

available soil. Black Walnut Sym

The results of this study show signifi- Proceedings, Black Walnut as a Cro

cant differences in height and caliper USDA For. Ser. Gen. Tech. Rep. NC-

growth of walnut among cover crop treat- 33-36.

ments. Although growth rates of black walnut in the clean-cultivated control treat- Todhunter, M. N. and W. Beineke. 197

ment were superior, the energy necessary to Effect of fescue on black walnut g

maintain this condition and the potential Tree Plan. Notes 30(3):20-23.

for accelerated erosion would render this

alternative less than desirable for pro- Waiters D. T. and A. R. Gilmore. 197

longed time periods in most management Allelopathic effects of fescue on 

situations Sericea lespedeza was able to growth of sweetgum. J. Chem. Ecol

maintain itself well when grown in associa- 2(4):469-479.

tion with black walnut and walnut seedlings

exhibited their greatest growth when associated with this forage species, relative to

the other cover crop species. It is suspected that the early retardation of growth

of black walnut when grown in association

with sericea lespedeza could be eliminated

by clean-cultivation during the first few

years, allowing the walnut trees to grow to

a height above that which the sericea

lespedeza would reach (0.9 m), followed by

' 
°

BLACK WALNUT SEED: FROM TREE TO SEEDLING 1

Robert D. Williams 2

Abstract--Recommendations are given for col- 3. Choose straight, vigorous seed trees

lecting seeds. Germination of unhulled nuts to increase chances of straight,

are compared with nuts hulled in, large and vigorous progeny.

small capacity hullers. Seed testing methods,

including X-ray, are discussed; the importance 4, Collect after the husk begins to turn

of, as well as how to determine, seed moisture color.

content is shown. Results from recent seed

storage and stratification trials are pre- 5. Place collected nuts in porous bags to

sented. _ prevent heat buildup. Heat destroys

the viability of the seed.

Hog farmers brag that their consumers use

everything but the squeal. Black walnut 6. Keep seed as cool as possible untll it

growers can be Just as proud. They market the is hulled, Hulling is not essential

stem, root, and limb wood of walnut for veneer, unless the seed is to be tested.

lumber, and speciality products; the walnut

kernels are food for man and animal. The wal- 7. Don lt waste time collecting seed from

nut shells are used as abrasives for deburring, poor seed chances. Concentrate your

•cleaning, and polishing; as additives in oil efforts where seed is plentiful.

'well drilling mud; and as filterlng agents in Seed crops can be estimated by

smokestack scrubbers. 3 But the most important counting the number of trees that have

use of the nut is its role as seed, to perpet- seed in a sample of I0, and by -

uate the species. Squirrels eat much seed, but counting the number of nuts per clusthey are also responsible for most of the nat- ter. If 7 of the 10 trees have 1 nut

ural reproduction of walnut through forgotten per cluster or if 5 of the I0 trees

or unused food caches. Humans, too, consume have 2 or more nuts per clustery there

someseed as food, but they also collect tons will be an average seed crop. If 7

of seed each year (when it is available) for or more of the 10 trees have 2 or

direct seeding or for producing seedlings at more nuts per cluster, there _rlll be

nurserles, a heavy crop.3 Before collecting nuts,

crack a few from each tree. If fewer

than 6 of 10 nuts from a tree have

SEED COLLECTION good kernels, don't collect from that

tree.

Some basic principles to remember when

collectlng walnut seed are:

HULLING

1, Collect seed up to 150 miles south of

the planting site (Bey 1980) or use Walnut seed should be hulled to perform

the seed collection zones recommended the float and X-ray tests, to facilitate meby Deneke et al. (1980). chanical sowing, and to reduce bulk for seed

stratification or storage. Seed may be hulled 

2. Keep records on the performance of by hand or by mechanical huller.

progeny from individual seed trees.

Seed and seedlings from local stands Some hullers damage the germlnatlve camay perform very differently, pacity of the seed. The nuts are forced up

!Paper presented at the Joint meeting of

the Northern Nut Growers Association and the

Walnut Council. Purdue University, West

Lafayette, IN, August 13, 1981. 3personal communication with Gus Rutledge,

=Robert D. Williams, Principal 1981. Ha=sons Products Company, Stockton,

Silviculturist, North central For. Exp. Stn., MO.

Bedford, IN.

1i4
against-a metal grill which rubs off the hull, The cracking test is the cracking o

or they. are flailed with chains to break and randomly drawn number of seeds to examine 

loosen the hulls. Probably the net effect on kernels. The viability of a seedlot is e

the seed is influenced, too, by the quantity of. mated by determining the percentage of s

seed in the huller at a given time. The fewer filled with firm, well-developed, white e

the seed the more punishment they take and the sperm. Bad seed contain distinctly shriv

greater the probability that the seed will be kernels, or the kernels may be buff or t

damaged and not germinate, some may give off a rancid odor. Some ba

kernels may be watery or be filled with a 

We conducted a study to determine whether clear, or milky oozing liquid and give o

elther of the two hullers we used might destroy foul odor.

the germinatlve capacity of the seed. Our

tests were conducted wlth small seedlots, which X-raylng seed is a useful and relatl

probably biased our findings in favor of the new method to determine more precisely t

small huller. Because unhulled seed floats quality of the seed. Every seed is X-ray

and unhulled seed was one of our variables, those seeds that do not show a filled see

J none of the seed was float tested. All seed ity with well-deflned outlines of the see

was fall sown. Germination was 48 ,percent for kernel on the radiograph are discarded. 

unhulled seed, 60 percent for seed hulled in walnut seed is laborious, the film and pr

the small huller, and 25 percent for seed cesslng are expensive, and the radiologis

hulled in the big huller. 4 Although mechanical be a skilled technician to improve over 

hullers may reduce germination, I believe ger- results of the float test. For example, 

minatlon of seed hulled in the big huller of our first X-ray studies, germination w

would have been higher if the huller had been percent for unhulled seed, 60 percent for

run at normal capacity. Also, the float test hulled, 72 percent for hulled and floated

will eliminate most of the bad seed, and hulled 74 percent for hulled, floated, and X-ray

and float-tested seed will germinate more com- seed. In a later study, which contained 

pletely than unhulled seed. seed sources, germination was 70 percent 

unh_!led seed, 69 percent for hulled, 80 

for hulled and floated, and 75 percent f

SEED TESTING hulled, floated and X-rayed seed. Germin

for the ten seed sources ranged from 53 

To estimate the number of seedlings that percent.4

will be produced, any sower should know what

portion of his seed has the potential to get _ Both the float test and the X-ray te

minate. Unfortunately, short of germinating be done soon after the seed is hulled. 

the seed, only an estimate of germinative allowed to dry longer than 3 days, much 

capacity is available. Walnut seed requires a seed will float and the air pockets, whic

minimum of 90 days' stratification, so ger- one indication of bad seed, will show up 

mlnatlon tests take too long to be useful to radiographs. In one trial, after 8 days 

anyone sowing seed in the fall, immediately drylng, the float test indicated that all 

after collection. In addition to the germi- in some sources were bad. According to X

natlon test, two standard tests and one tel- and cracking tests done on the same seed 

atlvely new test estimate seed viability: pies, X-ray showed that 83 percent of the 

(1) the float test, (2) the cracking test, and was good and the cracking test showed tha

• (3) X-ray. " percent was good.4 "

The float test separates filled from The ability of the radiologist to se

unfilled seed when hulled seed is placed in good from bad seed varies by seed source 

Water. Air spaces in the unfilled seed cause drying time. Some seed sources are more 

it to float, while the filled, good seed sinks, genic than others and radiographs are mor

To be effective, the float test should be easily discernible. If dried too long, a

conducted within 3 days after the seed is pockets appear in radiographs of good see

hulled. If too dry, even good seed will float, causing them to appear bad. After 28 day

of drying, all seed appeared bad on the 

' graphs.

• SEED GERMINATION

Black walnut seed is dormant when i

from the tree, and must be stratified bef

it will germinate. In temperate climates

4Data on file at Bedford, IN. as Indiana, overwintering in the seedbed, 
fall so,ring, usually satisfies the seed's soaked seed germinated. Seed moisture content

requirement for stratification and the seed differs by seed source, too. For example,

geminates normally the following spring. Some- after 14 days of drying, moisture content of

times, however, seed does not germinate until one seed source was reduced by8 percent while

after two winters in the seedbed. Second-year moisture content of another was reduced 26

germination has been observed in nursery seed- percent.4

beds and by those direct seeding the nuts in

the field. Seed source plays an Important Moisture content is easy to determine.

role in stratification, so some of the northern First, weigh a sample of 5 nuts and a cloth

seed Sources might not germinate promptly or bag large enough to hold the nuts; crack the

completely if fall-sown in southern nurseries nuts and place all pieces in the bag; place the

without prior cold room stratification, bag of nuts in an oven preheated to 103 ° C;

leave in the oven for 16 hours, then take out

There are three primary methods of strat- and rewelgh (Bonner 1980). The formula for

ification. In addition to fall sowing, a percent moisture content is:

natural stratification of the seed, we have

used cold stratification and pit stratification. M.C. = wet weight- oven dry weight x i00

Our cold stratification was a cold storage room wet weight

i at the Va!lonia Nursery wlth a temperature of

i 37°F. Hulled seed was dipped in water, allowed To store nuts in a home refrigerator at

to draln up to 15 minutes, placed in 4 roll about 40 ° F, moisture content should be replastic bags, and closed with a wire tie before duced to about 30 percent. To store nuts in a

being placed in the cold room. home freezer where the temperature is about

• 0° F, seed moisture content should be reduced

Pit stratification was accompllshed by to about 17 percent (Williams 1971).

placlng hulled seed in pits about 3 feet deep.

In normal stratification, alternate layers of /

seed and about 2 inches of sand would be built SEED STORAGE

up to within 6 inches of the soll surface.

Reliable, inexpensive seed storage techFall-sown seed usually germinates more nlques are needed for large seed quantities.

promptly and more completely than either cold- Bumper seed crops occur locally in some years,

or pit-stratlfled seed. In a study involving but in ocher years no seed is produced. Walnut

I0 seed sources, germination of fall-sown seed seed may be scored 1 full year in cold storage

was63 percent; germination of cold- and pit- with little loss of viability (Williams 1971).

_tratified seed was 58 percent and 52 percent, However, walnut seed is so bulky that cold

respectively.4 Germination by seed source storage is too expensive for large seedlots.

! ranged from 43 to 71 percent. In another study So we have been searching for an alternative

germination was 46 percent for fall-sown seed, storage method.

42 percent for cold-, and 28 percent for pitstratified seed. 4 Because fall-sown seed ger- First, we tried ambient temperature storminates sooner in the spring, the 1-year-old age. 4 Seed was sheltered from precipitation

seedlings are usually larger than those from but subject to fluctuating temperatures in one

spring-sown stratified seed. location in Georgia, two locations in Illinois,

three locations in Indiana, and one location in

_. Length of stratification is important, Minnesota. If kept in ambient temperature storespecially for greenhouse work or for seed age over wlnter, then placed in cold storage

preparation for spring sowing. All seed until it was fall-sown, some of the seed from

sources that we tried required at least 60 each storage location germinated. But seed

days Incold stratification. However, most kept at ambient temperature the full year,

seed sources germinate more completely after did not germinate.

90 days' stratification, and seed germinates

most promptly after 120 days in stratlficatlon. 4 Next, we tried storing seed in root cellars. 4 Although there was a Sharp loss in

viability, some seed geminated after a full

MOISTURE CONTENT year in cellar storage. For example, seed

collected from 10 southern Indiana seed sources

Moisture content plays an important role in 1978 was stored in three different cellars

in the behavior of black walnut seed. Seed and in pits dug at Indiana's Vallonla Nursery.

moisture content must be reduced for cold After a full year in storage, the seed was fallstorage, and dried seed must Imbibe water before sown in the nursery. Germination of fresh seed

itwill germinate. For example, 44 percent of from the same seed sources sown in the fall of

presoaked seed with previously reduced molsture 1978, right after collectlon, ranged from 58

content geminated, but only 29 percent of non- percent for the poorest seed source to 95

•

Q
°

percent for the best. Average germination was 2. Remember that seed quality and de

81percent. After a full year in storage, _ opment of seedlings from seed tre

germination was 22, 23, and 24 percent fo_ differ within local stands.

seed stored in the three cellars and 23 percent

for seed stored in the pits. 4 Although 23 3. Collect from productive stands an

percent germination is not satisfactory, the high-quality trees.

cellar storage results are encouraging. If we

use different kinds of bags, or manipulate the 4, Hull and float test within 3 days

humidity, or provide some cooling, cellar storage may preserve seed viability at a satisfactory 5. Use a huller with care because it 

level, damage the seed and reduce its ge

native capacity.

SOWING SEED 6. Sow seed the fall it's collected 

possible, and never let the seed 

Plantations may be established by direct out excessively.

seeding or by planting seedlings. To produce

seedlings for transplanting in the field, the 7. Stratify the seed in a cold room 

seedbed should be prepared in much the same way at least 90 days before sowing wh

aspreparing soil to sow corn or beans in a fall sowing is not possible.

garden.

° 8. Try storing surplus seed in cellar

For natural stratification and best get- when cold storage is not available

mination, sow the seed in the fall. To produce

about 6 seedlings per square foot, sow 12 seeds

per square foot (3 x 4 inch spacing) if seed LITERATIYRE CITED

tests indicate 50-percent germination. Adjust

the sowing rate according to the seed quality. Bey, Calvin F. 1980. Growth gains from m

• Seed should be covered with 1 1/2 to 2 inches black walnut provenances northward. J. 

• of soil (a rule of thumb is to cover 2 times 78(10):640-645.

the diameter of the seed). If seed is sown in Bonner, Franklin T. (In press). Measureme

the spring, it should be stratified at least of seed moisture in Ca__ovata and Jugl

90 days before sowing. For example, if seed is nigra. In IUFRO Symposium on Seed Stora

to be sown March 15, the seed should be placed Petawawa_-Canada, Sept. 1980.

in cold stratification by December 15. To Deneke, Frederick J., David T. Funk, and C

protect the seed from predators, cover it with Bey. 1980. Preliminary seed collection

• wire screening or lathe fencing, zones for black walnut. U.S. For. Serv

Northeastern area state and private fore

If the seed is to be sown in the field, Broomall, PA. NA-FB/M-4, 5 p.

sow enough seed at each seed spot to ensure a Williams, Robert D. 1971. Storing black w

seedling. If germination capacity is 50 percent, seed. North. Nut Grow. Assoc. Annu. Re

sow 2 seeds per seed spot. To protect the seed 62_87-89.

from predators, cover the seed spot with manure Williams, Robert D. and David T. Funk. 19

(Williams and Funk 1979) or with wire screen Cow manure deters rodents from stealing

staked down over the seed. Sow the seed about seeded black walnut. North. Nut Grow. 

2 inches deep. Annu. Rep. 69:43-48.

To shorten the time between sowing and seed

germination, thus providing less time for ro"

dents to pilfer the nuts, sow stratified seed

in the spring. Use manure or screen wire over

the seed to protect it from squirrels.

SUMMARY

There's still much to be learned about

blackwalnut seed. But for best results we

• know to:

i. Collect seed up to 150 miles south of

the planting site.

o 

"',l.

- IIIlI ............................ _..... ' Ill I ........ _ ........ I[I _ _- III I __ LI ._ I _
I

]

A SCREENING OF VESICULAR-ARBUSCULAR (VA)

1

MYCORRHIZAL FORMING FUNGI ON BLACK WALNUT SEEDLINGS

i M.W. Mellchar*, H. E. Garrett and G. S. Cox 2

I

!

i. fungi Absontracthet.--The growth effects and developmen of VAt mycorrh of black lzal walnut forming(Ju__-

} _._lan_sn.l ra L.) were studled. Percentage infection, root

i dry weight, stem dry weight, total seedling dry weight,

stem diameter and stem height, were determined for each

: seedling. Seedlings inoculated with Glomus microcarpus,

i Glomu s microcarpus+Glomus fasclculatus, and Glomus microcarpus+Glomus etunlcatus+Glomus fasciculatus demonstrated

superior growth and development to those inoculated with

other species or left unlnoculated.

INTRODUCTION chances of natural colonization of walnut root

systems under nursery conditions is low due to

The multitude of microorganisms which seedbed sterilization and the fact that endollve on or near the feeder roots of trees, mycorrhlzal spores are disseminated only

agronomic crops and other plant types inter- through the soil. At best, recolonization of

act with the plant roots to form a functional nursery beds is a slow process following steriassociation which plays a vital role in many llzation. Without artificial reinoculation,

I physiological processes. Microbial processes the benefits of a mycorrhizal relationship are

inv ism.olveThesaprmoosphy t uni tlsvers m, alpathmut ogenuallsimsticand rela mututioal-n- ntothe fwalnu orthctomirnootg insystadv em anbcey inodif gen theousinvasi mycoonrrhoif-

| Ship Of plants is the mycorrhlzal association zal fungi at the planting site. Unfortunately,

i which involves various root-lnhabiting fungi with our limited knowledge of walnut mycorrhiand plant feeder roots, zal relationships, at present it is impossible

,

to recommend a specific organism for artiflcial

! The benefits of mycorrhlzae to plant inoculation.

! growth and development are well documented

for ectomycorrhlzal tree species (Garrett, et The objective of this study was to evalu-

! al., 1979; Marx, 1979; Vlasov, 1955). However, ate the effects of five veslcular-arbuscular

fewer studies have been made on endomycorrhizal (VA) endomycorrhlzal fungi on the growth and

Woody types (Kormanlk, et al., 1979; Starkey development of black walnut seedlings.

and Brown, 1977). In particular, little infor-

• matlon is available on the endomycorrhizal re- MATERIALS AND METHODS

lat!onshlps of black walnut (Juglans nlgra L.),

_ the premier timber species of the eastern Unl- The study was conducted within a greeni ted States (Ponder, 1979). This is unfortunate house at the University of Missouri-Columbia.

since black walnut is noted for poor growth and Natural light conditions were utilized and

development during the first two years after temperatures ranged from 25-29 degrees Centi-

_, outplanting (Williams, 1970) and could benefit grade. The greenhouse was covered with a

greatly from mycorrhizae. Moreover the shadecloth which transmitted 50 percent of full

sunlight.

' , -

Five VA mycorrhizal fungi, Glomus caleIpaper presented at the Second Joint donlus (Nicolson and Gerdemann), Glomus fasciMeeting of the Northern Nut Growers Associa- culatus (Thaxter sensu Gerdemann), Glomus mition (72nd Annual Meeting) and the Walnut crocarpus (Tulasne and Tulasne), Glomus e--------t

Council (12th Annual Meeting), West Lafayette, catus (Becker and Gerdemann) and Glomus mosseae

Ind°iana, August 9-14, 1981. (N'ic01son and Gerdemann) were used as inocula

2* '

Research Forester, Kansas State University, Manhattan, Kansas. Associate Pro- The inoculum was produced by growing each

fessor and Professor, respectively, Forestry fungus in association with soybeans (Glycine

Department, University of Missouri-Columbla. maX, Merrill) of the Clark variety. Potting

-

118
soil was steam sterilized and soybean seeds After 198 growing days, all seedling

surface sterilized in a I0 percent, sodium lifted by immersing the entire container 

hypochlorite solution to minimize contamina- water and loosening the growth medium, t

tion. These open pot cultures were maintained abling it to fall away from the root syst

in the greenhouse for Ii0 days until the soy- Care was taken to insure that the fine f

beans flowered. After flowering, the above- roots were retained. Percentage infectio

ground portion of the soybean plant was re- root dry weight, stem dry weight, stem h

moved. The remaining soil-root mixture was and stem diameter were determined for ea

allowed to dry, ground, and placed in sterile seedling. Percentage infection was asse

containers for future use as inoculum, a modification of the root-slide techniqu

Starkey (1977).

To minimize genetic variability among the

walnut seedlings, half-sib seed of the Thomas RESULTS

variety were selected for uniform size and

used in all treatments. The seed were surface Inoculation of container-grown black 

sterilized in a 10 percent hypochlorite solu- nut successfully produced viable VA endom

tion for 60 seconds, rinsed twice in distilled rhizal associations. Incorporation of s

water and pregerminated in sterile vermiculite root fragments and fungal spores grown i

prior to planting. ' pot-culture°s yielded infection percentage

greater than noninoculated controls in a

• The soil mixture consisted of equal vol- treatments. The percentage mycorrhizal 

umes of soil, peat and vermiculite. The mix- al roots ranged from a high of 66 in the 

ture was steam sterilized at i00 degrees cen- microcarvus (60)-fasciculatus (38) treatm

tigrade for a period of 45 to 60 minutes, to a low of ii in the control (Table 2). 

The mixture was then placed in five-gallon infection in the control seedlings was a

pecan cans (nine inches in diameter, 20 inches buted to a lack of complete soil steriliz

deep). The containers were watered repeatedly during steaming and not to reinvasion. 

• for a period of ten days prior to inoculation lation with G. microcarpus (60)-fasciculat

• andplanting to insure that the entire soil (38), G. caledonius, G. fasciculatus (56

profile was saturated, microcarpus (32) and G. microcarpus (48)

etunicatus (28) all resulted in significa

Inoculation consisted of thoroughly mix- increases in infection over the control. 

ing 400 milliliters of soybean VA inoculum fection percentages were 66, 61, 61 and 

throughout the sterilized soil:peat:vermicu- respectively.

lite growth medium. In addition, a tone'shaped

• area was formed at the surface of the soil mix- Inoculated seedlings also produced 

ture and filled with 150 m/lliliters of inocu- root dry weights than noninoculated contr

lure. The germinated walnut was placed directly stock. Glomus fasciculatus (56)-microcarp

on top of the inoculum to insure taproot-ino- (32), G. microcarpus (60)-fasciculatus (

culum contact. Five species of fungi, used G. microcarpus (48)-etunicatus (28) treat

either singly or in combination, were employed resulted in significant increases in dry 

as inocula. The seven treatments were Glomus of 118, 113 and 98 percent, respectively, 

caledonius, Glomus mosseae, Glomus microcar- the control. Inoculation with the relati

pus, Glomus microcarpus (60%)-Glomus fascicu- pure culture of mG. microcarpus yielded s

latus (3.8%), Glomus fasciculatus (56%)-Glomus 83 percent heavier than those produced i

microcarpus (32%), Glomus microcarpus (48%)- noninoculated treatment.

Glomus etunicatus (28%) and a noninoculated

control (Table I) -- the percentages given for An apparent correlation exists betwe

the combination treatments represent the pro- percentage infection and root dry weight. 

portion of spores present of that particular lings inoculated with G. microcarpus (60

spore type. The soll was saturated every three ciculatus (38), G. fasc--iculatus (56)-micr

to five days throughout the study so that seed- pus (32) and G. _crocarpus (48)-etunlcatu

lings were never under any degree of water (28) all demon--strated increased root dry 

• stress, as a result of increased mycorrhlzal infe

However, the root dry weight of G. caledo

A completely randomized statistical design seedlings was only 51 grams, even though 

involving the seven mycorrhizal treatments was donius produced the second highest infect

• used. Each treatment was replicated three percentage (61%). The increased absorpti

times with five seedlings in each replication, root surface area of the mycorrhizal seed

• providing 15 seedlings in each treatment. All resulted in a significant increase in to

data were subjected to analysis of variance growth.

and the means were analyzed using Duncan's New

Multiple Range Test at the 0.05 alpha level.

mm
°

Table l.--Treatments consisting of six different isolates and/or combinations of VA mycorrhlzal

fungi (Glomus sp.) and a control which were used to inoculate black walnut seedlings.

Spore types and counts* Total number of

spores per

Treatment name G. cale. G. micro. G. moss. G. fasic. G. etun. I00 ml soil

Control ......

G. caledonius 136 35 - - - 171

G. mosseae 8 - 49 3 - 60

G. microcarpus 21 89 - - - Ii0

G. micro (60)-fasic (38) 6 i00 - 63 - 169

F. fascic (56)-micro (32) 12 34 - 59 - 105

G. micro. (48)-etun (28) - 63 - 33 36 132

*Number in ( ) indicates percentages of total number of spores present of that respective spore

type for that particular treatment. G. cale.=Glomus caledonius, G. micro.=Glomus microcarpus,

G. moss.=Glomus mosseae, G__.fasclc.=Gl--omus fasclculatus, G. etun.-L-Glomus etunlcatus.

i

Table 2.--The effect of inoculation with VA mycorrhlzal fungi (singularly and in combination)

from the family Endogonaceae on growth of black walnut seedlings.

Root dry Stem dry Total dry Stem Stem

Infection weight weight weight diameter height

| Treatment _ (gin) (gin) (gin) (cm) (cm)

• G. micro (60)-faslc (3.8) 66 a 102 ab 5.5 a 118.9 a .65 ab 35.9 a

(ii3) (53) (i02) (i4) (i7)

i G. faslc (56)-mlcro (32) 61 a 105 a 5.5 a 121.3 a .68 a 34.9 ab

| . _ (118) (53) (106) (19) (13)

' G. micro (48)-etun (28) 54 abc 95 abc 4.8 ab 109.7 ab .64 ab 32.1 ab

" (98) (33) (86) (12) (4)

G. mlcrocarpus 37 bcd 88 abcd 5.6 a 121.8 a .65 ab 30.4 ab

• (83) (56) ' (107) (14) (-I) 

= G mosseae 33 bcd 70 abcd 4 0 ab 82 9 ab .60 bcd 34.0 ab

$ (46) (II) (41) (5) (i0)

G. caledonlus 61 ab 51 cd 3.5 b 61.8 b .60 bcd 31.6 ab

(6) (-3) (5) (5) (3) "

! Control II d 48 d 3.6 b 58.9 b .57 d 30.8 ab

Means not sharing the Same letter differ significantly at the alpha =0.05 level according to

' Duncan's New Multiple Range Test. Number in ( ) denotes the percentage difference from the

. . control.

Mycorrhlzal seedlings were consistently ferences were observed between any of the mylarger in diameter and of greater dry weight corrhizal treatments and the controls. Seed-

° ' than those which were not inoculated (Table lings inoculated with G. mlcrocarpus (60)-

2). The single exception was G. caledonlus fasciculatus (38), howe--veT,were 17 percent

stock which averaged 0.I g less weight than taller than the controls; G. fasciculatus (56)-

the nonmycorrhlzal seedlings. Inoculation microcarpus (32) and G. mos--seaeseedlings were

wlth G,. fasciculatus (56)-mlcrocarpu s (32), 13 and I0 percent tall--er, respectively.

_G.mlcrocarpus (60_-fasclculatus (38), G.

micr0carpus , and _G" mlcrocarpus (48)-etunl- DISCUSSION

catus (28) significantly increased stem di-

&meter 12 to 19 percent compared with con- Endomycorrhlzal inoculation of black waltrols, nut in containers is feasible under greenhouse

conditions and, in all likelihood, could also

tical Sternly byheino ightculawas tionnotasaffwerecetemany d asofdrama- the besultsaccoindi mplished cate that in nurs a suitabl ery seeedbeds. inoculumOurforreother growth features. No significant dlf- stimulation of the early development of endo120
°

mYcorrhizae on eastern black walnut may be pre- LITERATURE CITED

pared by grinding the soil and root systems of

soybeans, which have been inoculated with one Garrett, H. E., G. S. Cox, R. K. Dixon and 

of several species of Glomus. Soll sterillza- M. Wright. 1979. "Mycorrhizae and the 

tlon either by steaming or fumigation (a common tiflclal regeneration potential of oak.

nursery practice) will obviously decrease the 82-90. In: P. Pope (ed.) Proc. of the 

chance of mycorrhlzal development as demonstra- John S. Wright For. Conf., Regenerating 

ted by the control seedlings which had only ii in Upland Hardwood Forests. Purdue Uni

percent of their root systems colonized, sity, West Lafayette, Indiana.

Kormanik, P. P., W. C. Bryan and R. C. Schu

The early development of endomycorrhizae 1979. "Growth, endomycorrhizal infectio

on Walnut seedlings in this study was associ- and nutrition of seedlings of nine swee

ated with significant increases in growth and families with different VA endomycorrhiz

development. Inoculation with G. mlcrocarpus fungi." In: Fourth North American Conf

provided an 83 percent increase in root dry ence on Mycorrhizae. Fort Collins, Col

weight over the noninoculated controls, while rado. (abstract)

; a combination of G. fasciculatus (56)-microcar- Marx, D. H. 1979. "Synthesis of Pisolithus

pus (32) yielded a 118 percent increase. This tlnctorius ectomycorrhizae on white oak

increased root development is especially import- seedlings in fumigated nursery soil." 

ant in many Midwest soils, since it enables the Department of Agriculture Forest Servic

seedling to better meet its moisture and nutri- Research Note SE-280.

ent needs. Ponder; F. 1979. "Soil structure and myco

: rhlzae encourage black walnut growth on 

A complementary relationship between inoc- fields." U.S. Department of Agriculture

ulation, root development and shoot development Forest Service Research Paper NC-132.

was also pronounced after one growing season in Runov, E. V. 1955. "Experimental introduct

this study. Inoculation with G. microcarpus, of mycorrhizae into oak sowings in arid

G. fasciculatus (56)-microcarpu--s (32)and G. steppe." p. 174-186. In: A. A. Imshen

microcarpus (60)-fasciculatus (38) provided (ed.), Mycotro_hy in Plants. Academy o

Increases in stem weight of more than 50 per- Sciences of the USSR, Institute of Micr

cent and increases in stem diameter from 12 to biology. Moscow.

19 percent. Although size is not necessarily Starkey, D. A. 1977. "Effects of three ve

a criterion of physiological condition, survival ular-arbuscular mycorrhizal fungi on gr

and growth after outplanting is better with of yellow poplar." Masters thesis. Un

larger stock. A common morphological feature verslty of Missouri, Columbia. I01 pp.

used in grading nursery walnut planting stock Starkey, D. A. and M. F. Brown. 1977. "Ve

is stem diameter. Seedlings I/4-1nch (0.64 icular-arbuscular mycorrhizae of yellow

cm) or larger in diameter survive better and poplar: Effects of seedling growth in f

grow faster than smaller ones following out- est nursery soil and in an artificial r

planting (Williams, 1970). Inoculation with G. urn." p. 42. In: Third North American Co

mlcrocarpus (60)-fasciculatus (38), G. fascl--- ference on Mycorrhizae. Athens, Georgi

culatus (56)-mlcrocarpus (32), G__.mlcrocazpus (abstract)

(48)-etunicatus (28) and G. mlcrocarpus re- Vlasov, A. A. 1955. "Importance of mycorr

suited in stem diameters of 0.65, 0.68, 0.64 za for forest trees and procedures for 

and 0.65 cm, respectively. Control seedlings stimulation." p. 101-117. In: A. A. Im

averaged only 0.56 cm which is less than the netskll (ed.), Mycotrophy in Plants. A

• recommended I/4"-inch limit for culls, demy of Sciences of the USSR, Institute 

Microbiology. Moscow.

CONCLUSIONS Williams, R. D. 1970. "Planting large bla

walnut seedlings on cultivated sites." 

This study indicates that walnut seedlings Department of Agriculture Forest Servic

greater than I/4-inch in diameter can be con- Tree Planters' Notes 21(2):13-14.

sistently produced by artificially inoculating

soils with certain species of Glomus. Production of uniform nursery stock of this size

. could greatly reduce production costs by reduclng the number of cull seedlings. In addition, such stock would exhibit greater survi-

• val and growth rates when outplanted.
. •

. A SILVICULTURAL-ECONOMIC MODEL

FOR BLACK WALNUT 1

Warren H. Kincald, William B. Kurtz and H. E. Garrett 2

,

Abstract.--The level of profitability from investment

in black walnut productio;1 is directly related to the

_ level of management intensity. Five different management

regimes ranging from walnut timber only to timber, nuts,

• soybeans, winter wheatl fescue hay and grazing are evaluated in terms of internal rate of return and present net

worth. Management regimes are synthesized for two sites

(SI-80 and SI-65) which support different annual diameter

growth rates. Internal rates of return, from least-to

most-lntenslve management, ranged from 6.68 percent to

15.91 percent on the higher quality (SI-80) site and from

! 4.26 to 13.00 percent on the lower quality (SI-65) site.

!

Silvlcultural-economic relationships with- tlmatlon of parameters so necessary for the de-

! in black walnut management regimes are readily velopment of a complete silvlcultural-economic

i examined using a systems studies approach model of walnut management systems.

! (Johnson and Rausser 1977). Walnut has been ?

encompassed with a comprehensive reporting of In this paper we will present an examlna-

'_ management techniques (Funk 1966, Dillow and tion of several black walnut management reHawker 1971, Dillow 1975). Furthermore, much gimes. Earlier work (Callahan and Smith 1974,

: -informal information is available from indi- Garrett and Kurtz 1980) integrating the silvi- 

vlduals currently growing walnut, educators and cultural and economic aspects of black walnut

| researchers. Unfortunately, useful operating management have provided the building-blocks

data for evaluating economic aspects of walnut for this study.

growth responses is rather sparse. While llterature is available on growth responses to WALNUT MANAGEMENT REGIMES

many treatments, few studies have presented

adequate economic data. Moreover, few planta- The development of a complete, single sil-

....- tions of sufficient age presently exist that vicultural-economic mgdel is not possible at

have undergone management techniques currently this time due to thelack of adequate data.

recommended. Complex interactions vary re- However, separate models for different walnut

_. sponse s of many treatments and hinder the es- management schemes have been developed, with

: each model containing a number of assumptions

concerning recommended treatments and expected

growth rates. For the purposes of this analyIpaper presented at the Walnut Council/ sis, five regimes have been selected:

NNGA Symposium, West Lafayette, Indiana, I) Walnut timber (veneer logs)

August 9-14, 1981. 2) Timber and nuts

Funding for this work was provided in part 3) Timber, nuts and winter wheat

by the USDA Forest Service, North Central For- 4) Timber, nuts, soybeans, winter

est Experiment Station, Carbondale, Illinois, wheat, fescue and grazing

under Cooperative Agreement Number 13-700, As- 5) Timber, nuts and grazing

sessment of Silvlcultural-Economlc Relatlonshlps Many other regimes exist; each landowner is 

for B_ack walnut Management. limited only by land quality and his manage- 

• Forester, Missouri Department of Conser- ment preferences.

vatlon, New Madrid and professors of forestry,

• University of Missouri-Columbia, respec- The schedule of activities for each retlvely, glme and associated costs and revenues was

subjected to an investment analysis using a

i22
financial return algorithm developed by Goforth _

_nd Mills (1975). Profitability indices are ///-_,_ma,

w_d cam,m

shown in the form of internal rate of return ]__._co,__, a

and present net worth. The algorithm also pro- [8__a_mm_ .

vides a sensitivity analysis for determining _l-'_.._l=Ye_mme_aiTi

proportionate changes in presentnet worth and | -A,,u_m_,su

internal rate of return to changes in data input S. _ Revenues _ Gm_e_

Each regime is analyzed for two different

sites, medium quality (Sl 65) and high quality

(Sl 80). The high quality site is assumed to __

be capable of a DBH growth rate of 1/2 inch UmdSJ.

per assumed year,towhile be capable the medium of supporting quality site a 1/3is inch 1/Nut returns would not _ntribute 

per year growth rate. All regimes are carried walnut timber regime.

- ; to a rotation length of 60 years. This combination of options provides I0 different alter- Figure l.--The relationship between co

natives. Each analysis contains a series of revenue activities associated with th

assumptions about activity schedules, prices, timber and nuts management regime.

yields, costs and benefits associated with

. walnut management (Table I).

Trees are planted at a spacing of 

Walnut Timber feet (108 trees per acre) allowing max

crown development and some opportunity 

The walnut timber regime emphasizes wal- selection gains. Again, following thi

nut plantation management specifically for 27 trees remain for final harvest. Th

veneer logs (Figure I). Trees are planted at occur when CCF reaches 90 and each thi

a 12xl2-foot spacing (300 trees per acre) to reduces CCF to 60. This CCF range, al

allow natural pruning and increase the poten- a reduction in pruning heights from th

tlal for a straight central stem. Planting a only regime, will allow maximum develop

large number of trees allows for selection of crown area.

gains since only 27 trees per acre will remain

for final harvest. Trees are pruned to heights Timber, Nuts and Winter Wheat

that allow a 16-foot log to be taken at harvest

on excellent sites (SI 80). Prunings and thin- Multicropping management regimes 

• nings are scheduled to yield maximum benefits, the same schedule of activities as the 

. but also to minimize bole sprouting potential, and nuts regime, plus additional agricu

Thinnings are scheduled to occur when the crown activities (Figure 2). In this first 

competition factor (CCF)I/ reaches II0. Each cropping regime, walnut trees are inte

thinning will reduce CCF to 70. with winter wheat for the first I0 yea

the enterprise. While it is possible 

Timber and Nuts winter wheat could be produced longer 

Management techniques in this regime are

similar to the walnut timber regime, except

pruning and thinning schedules are changed to co,m_

provide a shorter log and a larger crown to

benefit nut production. The ultimate objective involves a series of nut yields beginning P,_ommn_l%inn|n,

• in year 20 and lasting throughout the remainder ___

, of the rotation; final harvest yields a veneer wh__l_

log that is I0 to 14 feet in length (Figure I).

NotRevenues WalnutGro

WheaYielc t _ Compon

IJ_-..._ ¢mmme._J l%innmg

• _ " I__ _,_H,,,,,_ 1/Crown competition factor is an index --- --'UmdSam.

of competition between trees in a stand. It

is expressed as a percentage of the ground Figure 2.--The relationship between co

area in the stand actually covered by tree revenue activities associated with t

crown area (Schlesinger and Funk 1977). ber, nuts and wheat regime.
i Table I. Costs and revenues of walnut management by production categories.

Category Description Price per unit ($)

Lan_ / High quality (SI 80) 1000.00/ac

• Medium quality (Sl 65) 800.00/ac

.

i Property taxes 2.50/ac/yr

Labor 6. O0/hr

Trees Establishment (equipment, manpower, stock) 1.25/tree

Weed control (chemicals and application) 45.00/ac

I • _ CMorre anagcetiv mente pruning (2 hrs/ac) 14.00 2.00//acac/yr

Pruning: 7 ft (5.0 hrs/ac) 30.O0/ac

I ' 9 ft (6.0 hrs/ac) 36.00/ac

II ft (6.8 hrs/ac) 40.80/ac

J 7-11 ft (2.4 hrs/ac) 14.40/ac

, _ 9-15 ft (3. I hrs/ac) 18.60/ac

11-17 ft (3.5 hrs/ac) 21.00/ac

Precommerclal thlnnlng:2_/ 2 inch DBH 4 86/sq ft

3 inch DBH 3.30/sq ft

4 inch DBH 2.31/sq ft

5 inch DBH 1.89/sq ft

6 inch DBH 1.47/sq ft

7 inch DBH 1.23/sq ft

8 inch DBH 1.95/sq ft

9 inch DBH .90/sq ft

I0 inch DBH .81/sq ft

Nuts 9.00 /cwt

i , Stumpage: I0 ft. log, I0.2" dibse ....

r

I0 ft. log, 13.8" dlbse 40.00 ea

I I0 ft. log, 17.0" dlbse 226.00 ea

i I0 ft. log, 19.8" dlbse 370.00 ea

log, dibse ....

14 ft. 8.9"

' 14 ft. log, 11.2" dlbse 37.00 ea

14 ft. log, 12.0" dlbse 45.00 ea

_ 14 ft. log, 14.8" dlbse 229.00 ea

i " 14 ft. log, 17.2" dibse 373.00 ea

i 14 ft. log, 22.2" dlbse 1009.00 ea • 14 ft. log, 25.9" dlbse 1446.00 ea

_ 16 ft. log, 10.5" dibse 38.00 ea

• 16 ft. log, 13.8" dibse 243.00 ea

16 ft. log, 16.0" dibse 396.00 ea

16 ft. log, 20.7" dibse 1089.00 ea

16 ft. log, 24.2" dibse 1570.00 ea

•_ Winter wheat Establishment 31.50/ac

Management 6.00 /ac

Fertilizer 33.50/a c

_ Wheat 4.50/bu

Soybean Establishment 39.50 /ac

Management 7.50/ac

Fertilizer 32.00/at

' Soybeans ll.50/bu

Fescue Es tablis hment 37.20/a c

• Management 7.50/ac

Fertilizer 25 80/ac

Seed 55.00/cwt

Hay (deduct .15/bale when seed is removed) .70/bale

• Fencing Perimeter fence: Establishment 42.00/ac

Maintenance i.25/ac/yr

Electric fence: Establishment 49.00/ac

Maintenance I.15/ac/yr

Removal 6.20/ac

Livestock SI 65 feed costs (1-15 yrs) 26.80/ac

SI 65 feed costs (16 yrs-rotatlon) 29.50/ac

°

124
Sl 65 other costs3/ (1-15 yrs) 29.40/ac

Sl 65 other costs_J! (16 yrs-rotation) 32.40/ac

Sl 65 receipts (I-15 yrs) 77.60/ac

Sl 65 receipts (16 yrs-rotation) 85.40/ac

Sl 80 feed costs (1-15 years) 29.50/ac

Sl 80 feed costs (16 yrs-rotatlon) 32.80/ac

Sl 80 other costs3__/ (1-15 yrs) 32.40/ac

SI 80 other costs3__/ (16 yrs-rotation) 36.00/ac

Sl 80 receipts (1-15 yrs) 85.40/ac

SI 80 receipts (16 yrs-rotation) 94.90/ac

Land sale price equals its purchase price to synthesize its holding cost.

Precommercial costs are determined using unpublished data on file at the

USDA Forest Service Forest Sciences Laboratory, Carbondale, IL. Cost

is a function of hourly labor rate, DBH, and the number of trees re-

^. moved. It is expressed as dollars per. sq. ft. of basal area removed.

_' _ _/Other costs include veterinary and medicine costs, labor costs, utilities

and machinery.

years due to the late spring leafing charac- ---umd_.m__- " l,---_i._,,_, \

teristic of black walnut, a conservative i0- //. W_dCo,mS _\

year estimate is used because of the lack of //% __Pmning _\

supportive data. During this period, yields /////---Cl,_r-len_m_ninqI_\\\

of winter wheat on the medium quality site /////_PrecommerciJThinning-_\\\\

(SI 65)" are expected to be i0 percent less I/////_AnnuaJExpen_----._l_\

• thermore, establishment of agricultural crops

' under a multicropping regime with black walnut

requires that approximately four feet of non- | _Fe_:_eEsml:311_ L=-,i __\\\ \

/ _r_. M_. I I 1__\\\\

oo o, iill

to facilitate management and reduce competi- C,_Uer-eee&Mgt

tion. This reduces usable agricultural land

area by approximately I0 percent. __u l___i__wm 

• Timber, Nuts, Soybeans, Winter Wheat, Fescue, s_m_m _d" _ i

, and Grazing I _vvlm...wl_e_Ylel,;-

r-_=.s.__,_ _ 7/////

_o Ho_y _ "////I

This most intensive multicropping, man- l_'"---Ca_e_e_" _////

agement regime (Figure 3) involves a schedule i__NutRmum, , ,///

that includes many aspects of agriculture-- .__ CommerciThin al Yietd.._.t//

again, these agricultural activities are per- _.. _,_H_,_ _'/

formed along with the timber and nuts activi- I.,_ndS_e,

. / ties. The proposed systems of multicropping

are designed with the needs of each crop in Figure 3.--The relationship between cost 

mind. " revenue activities associated with the 

-' her, nuts, soybeans, wheat, fescue and 

Increasing shade with increasing age of ing regime.

the walnut will reduce soybean yields in years

. . 6_I0 by an estimated 20 percent below that expected for years 1-5. Soybean yields are also soybean and winter wheat are suitable i

very sensitive to changes in site quality, crops with walnut, fescue also appears 

Yields on a medium quality site (Sl 65) are suitable companion crop once the trees 

reduced to 75 to 80 percent of the yields on enough to have a well-established root 

• a high quality site (Sl 80). Crop free rows Research has demonstrated increases in 

are maintained for the walnut trees to grow quality and quantity when grown in assoc

with a minimum of competition. Therefore, with walnut (Smith 1942, Garrett and Kur

• usable land area is reduced by about 10-20 1981). Harvest of fescue seed and hay b

percent, in year Ii and continues until year 15, 

shade substantially reduces seed yields. 

After dual cropping soybean and winter ferences in site quality also result in 

wheat for I0 years, fescue is established in percent yield reduction for fescue seed 

the areas between the rows of trees. Just as on medium quality sites (SI 65) in compa

to high quality sites (SI 80).

! ' 

i

1

,j •
°

Cattlel grazing operations begln in year Table 2.--Walnut management regimes ranked by

16 when fescue seed yields become too low to internal rate of return (IRR) within groups

add revenue to the enterprise. A perimeter of identical site indices (Sl) and rotation

fence must be constructed to contain the stock ages (RA). Present net worth is given for

and will remain to the end of the rotation, each management regime.

Interior fencing is not required since, by Regimes IRR PNW (7.5%)

year 16 or so, walnut trees should be large (percent) (dollars)

enough to withstand livestock damage. Techniques of grazing management comonly employed Sl 80, I/2 inch GR, 60 RA

in Missouri are used throughout the rest of Intensive

the rotation. multlcroppinl/= 15.91 1951.69

Timber, nuts, wheat 9.36 882.0 7

Timber, Nuts and Grazing Timber and nuts 7.71 133.88

Timber, nuts, grazing 7.44 - 42.01

Grazing operations in this regime (Fig- Walnut timber 6.68 - 575.28

ure 4) are similar to those found in the inSI 65, I/3 inch GR, 60 RA

tensive multicropping regime with the excepi tlon that grazing between rows begins soon af- Intensive i/ 13.00 778.62

ter seedlings are established. This necessi- multicropping--

tares utilization of a tree protection fence Timber, n_ts, wheat 7.76 65.16

I system, as well as the perimeter fence. Pro- Timber, nuts 5.92 - 559.47

o tective interior fencing consists of an elec- Timber, nuts, grazing 5.52 - 765.17

i trically charged wire that is suspended on Walnut timber 4.26 -1198.83

stakes positioned six feet on either side of

i

a row of trees. The interior fencing remains l--/Intensive multicropping refers to timber,

in place until the walnut trees are sufficientnuts, wheat, soybeans, rescue, and grazly large to minimize damage from grazing stock.

ing regime.

.... regimes since 300 trees per acre are planted on

i a 12xl2-foot spacing. Establishing 300 t'rees

per acre and harvesting only 27 at rotation end

provides an opportunity for selection gains to

, take place: However, the model used in this

. analysis did not consider increases in revenue

| other than those associated with an extra two

1 feet of veneer log taken at commercial thinnings

" and final harvest.

I_"_G"_ i Lower establishment costs and early reve-

_,_m [ ¢o,_o,m, ] nues from collected nuts helped to increase the

t_w_Pd_ems__ IRR of the timber and nuts regimes by about one

•I_ !. -- c_m_ 7hj.._/-//

|_i_///_ --N,t_eds _// percentage point above that observed for the

- thinnings and final harvest are shorter in

' length; but this allowed a larger crown to de-

_igure 4.--The relationship between cost and velop which increased nut yields. Nut yields

revenue activities associated with the tim- are important, not only because of the addibet, nuts and grazing regime, tional revenue they contribute, but because

of the timing of these contributions.

INVESTMENT ANALYSIS Internal rate of return can be raised 1.5

to 2.0 percent above that observed for the timRanklng of the five management options by bet and nuts regime by adding a winter wheat

internal rate of return and present net worth management objective for the first I0 years of

within identical site index and rotation age the enterprise. As with the addition of nut

groupings is shown in Table 2. Internal razes revenues, the additional revenues associated

of return for the "walnut timber only" regimes with wheat, and the timing of these revenues

Were the lowest of all regimes analyzed. This help to offset the high initial establishment

is largely due to the absence of early reve- costs.

nues from annual crops to help compensate for

thehlgh initial establishment costs. Estab- The addition of grazing operations when

llshment costs are very high for timber only establishing a timber and nuts regime provided

-

126
o

very lit-tie benefit in terms of IRR. High Garrett, H. E. and W. B. Kurtz. 1980. B

fencing costs reduce the profitability of th_s walnut multlcropplng management. Wa

regime. Grazing operations could be suspended Council Bulletin 7(I):15-19.

until approximately year 16, thus eliminating Garrett, H. E. and W. B. Kurtz. 1981. A

the need for protective fencing due to the uation of the black walnut/tall fesc

substantial size of the walnut trees, ture management system. Proceedings 

• International Grassland Congress, Le

Intensive multlcropplng is a useful prac- ton, Kentucky, June 14-24, 1981 (in 

tlce in helping to offset hlgh initial estab- Goforth, M. H. and T. J. Mills. 1975. A 

lishment costs that include high land prices clal return program for forestry inv

pald for better sites. In most cases, the -- including sensitivity of results 

higher cost pald for hlgh quality land is too errors. USDA For. Serv. Agrlc. Hdbk

extreme to be offset by added revenues from 18 p. Washington, D.C.

increased wood yields. However, this is not Johnson, S. R. and G. C. Rausser. 1977. 

true in the timber, nuts, wheat, soybeans, analysis and simulation: a survey of 

rescue and grazing regimes. Here, added reve- cations in agricultural and resource 

hues from increased wood and crop yields more nomics. In: A Survey of Agricultural 

than offset the higher land price., nomics Llte---rature,L. R. Martin (ed.

157-301. University of Minnesota Pr

CONCLUSIONs St. Paul, Minnesota.

Schlesinger, R. C. and D. T. Funk. 1977. 

Growing black walnut either for wood pro- ger's handbook for black walnut. US

ducts only, for both wood and nuts or in a Serv. Gen. Tech. Rep. NC-38, 22 p. 

multlcropplng management regime can be a pro- Cent. For. Exp. Stn., St. Paul, Minn

fltable, as well as enjoyable, endeavor. Smith, R. M. 1942. Some effects of blac

Level of profitability is closely linked to locusts and black walnuts on southeas

intensity of management. Ohlo pastures. Soll Scl. 53:14.

Quality of site also influences the level

of profitability within respective management

regimes. Obviously, the greatest influence of

the higher slte quality is apparent wlth the

most intensive multicropping regime.

Multicropping management offers the greatest returns because of its .more intensive use

of land. While slight sacrifices might be made

in agricultural crop yields and wood and nut

production, the early returns from agricultural production offset the hlgh initial cost

of walnut establishment and permits substantial

increases in profits.

' LITERATURE CITED

• Callahan, J. C. and R. P. Smith. 1974. An

economic analysis of black walnut plantation enterprises. Purdue University

Agrlc. Exp. Sta. Res. Bull. 912, 20 p.

West Lafayette, Indiana.

Dlllow, M. K. _1975. Bibliography of walnutsupplement no. 2. USDA For. Serv. Gen.

Tech. Rep. NC-13, 26 p. North Cent. For.

Exp. Stn., St. Paul, Minnesota.

Dillow, M. K. and N. L. Hawker. 1971. Annotated bibliography of walnut-supplement

no. I. USDA For. Serv. Res. Pap. NC-70,

• 23 p, North Cent. For. Exp. Stn., St.

Paul, Minnesota.

Funk, D. T. 1966. Annotated bibliography of

walnut and related species. USDA For.

Serv. Res. Pap. NC-9, 49 p. North Cent.

For. Exp _Stn., St. Paul, Minnesota.
-_ THE CHANGING STATUS OF PRIME AGRICULTURAL LAND:

!

I

.. FUTURE IMPLICATIONS

Luther B. Hughes, Jr.

Abstract.--Losses of prime agricultural land used

for food production in the U.S. continues at an alarming

rate. Losses of millions of acres of land to erosion,

' fuel and fiber crop production and conversion to nonI agricultural use, i.e: urban development, highways, etc.

occur annually. Conversion to non-agrlcultural uses

alone exceed one million acres annually. Continued losses

of this magnitude of food production potential has implications of changing the U.S. to a non-food exporting

country, a serious blow to world hunger demand.

I INTRODUCTION discussed the importance of better nutrient

efficiency and availability of nutrients for

World population is increasing at the rate future food production. Hughes (1971) stressed

_. Of more than 180,000 persons per day (Brown, the importance of proper pest control for

1978). The resulting annual increase in world maintaining high yields. However, with crop

i population is equivalent to more than one-thlrd these inputs, the availability of highly of the entire U.S. population. This population productive soils is still necessary.

; increase has caused concern about adequate

food production, especially for the future.

i Thomas Malthus, in the early 1800's, projected LOSSES IN PRIME AGRICULTURAL LAND

that human population would increase geometrically and food production would only increase Significant losses of highly productive !

arithmetically. Although the United States is prime agricultural lands are matters of great

a notable exception, the Malthusian theory has concern. Trends in U.S. land use are shown

been shown to be quite prophetic. This paper in Table i. Soil, relative to length of

attempts to point out how the potential for human llfe, is a non-renewable resource. Yet food production in the future is being danger- soils are often managed as if they are quickly

ously reduced, particularly in the U.S., by regenerated.

large losses of prime agricultural lands due

to current land use practices and changes in

land use. Cropping SYStems Alterations

, production requires many inputs, shortages brought

Petroleum in the 1970's

i_ludSng acceptable environmental and climatic additional new pressures for land use with

conditions, available nutrients, proper control suggestions of crop production for alternative

of pests including weeds and potentially fuel production. Alcohol production from grain

i_ productive soils or land. Barber (1976) crops, use of blomass and oils from crops may

eventually prove economically feasible. As

production of these "fuel crops" increases, a

subsequent decrease in available acreages for

o Ipaper presented at the Walnut Council/ food production follows. Projections of over

NNGA Symposium, West Lafayette, Indiana 20 million acres for grain for alcohol producAugust 9-14, 1981. tion alone have been reported in the National

Agricultural Land Study.

= 2The author is Associate Professor

Agronomy Department, University of Missouri- Similarly, if petroleum shortages continue,

Columbia. the manufacture of synthetic fibers may be

128
Jeopardized. Subsequent increases in fiber cropland have been occurring in recent ,

crop production may likely occur. The extent in Tennessee, Mississippi, and Missourl 

of food cropland "lost" will closely parallel in the Corn Belt, cropland losses in Iowa 

the extent of fiber crop acreage increase, exceeded 9 tons/ac/yr. These sell losseq 

dramatically reduce productivity for the

distant future. Losses of sell from the 

Table l.--Trends in Land Use. Includes United productive lands also cause additional p

States, Puerto Rico, and Virgin Islands. to consider more intensive uses of more 

Excludes Alaska. i marginal lands for producing food crops. 

more serious erosion may then result.

1958 1977 Percent Conversion to Non-Agricultural Uses

(Millions of Acres) Changed

Few losses in agricultural lands are 

Cropland 448 413 -8 permanent as losses to non-agrlcultural u

, Demands for land for urban, transportation

Pastureland, and water resource development uses exceed

native pasture, 485 541' +12 3 million acres each year. In many lnsta

and rangeland these demands have chosen the very best 

prime agricultural land. Prime agrlcu!tu

Forest land 453 370 -18 lands were removed at the rate of one mil

acres per year from 1966 to 1975 accordin

Urban land 51 90 +76 the National Agricultural Land Study. I

(over i0 acres) instances, buildings, concrete, asphalt 

water render this land permanently useles

Small areas of 7 9 +29 agricultural production.

open water

• This loss is so serious that Florida

Other 60 77 +27 Hampshire and Rhode Island will lose all 

prime agricultural land within 20 years 

Total 1,504 1,500 current loss rate continues. Many other 

will lose over ten percent of their best 

producing lands (Fields, 1980).

• . Accelerated Soil Erosion POSSIBLE SOLUTIONS

The greatest pollutant of U.S. streams National policy decisions will play

and rivers is soil. Most sediment originated large role in determining whether food p

as topsoil before detachment and removal by tion will be adequate to meet U.S. needs 

water. Few resources have been so badly future. Conversion of land to fuel and 

managed or so quickly depleted. Sell is

crops will reduce land for food productio

renewable only in geologic terms often Economics and petroleum supply may dictat

requiring hundreds of years for an inch of that decision process.

soil development from bedrock. Conversion of

land to more idtensive crop use, i.e. pasture Accelerated sell erosion cannot con

• land or forest land to row cropland, often

at present rates without greatly reducing 

preceded accelerated erosion. One-third of

soil's productivity. Advances in conserv

the present U.S. cropland has already been

tillage or reduced tillage methods will 

lost by erosion (Pimentel, et al., 1976).

fully play a strong role in reducing ero

Careful management of marginal lands wil

Natural processes of soil formation allow

tolerable or permissible erosion to average necessary. Hupe (1981) reported that wa

• production had a positive effect on fora

3-5 tons/ac/y r implying that soil formation production, especially fescue. Findings 

at that rate allows no loss in productivity this nature may help offset yield reducti

(Kohnke, 1969) However, soil erosion often due to erosion. If voluntary soil conse

far exceeds the "tolerable" limit. Average efforts do not progress, legislative act

soil losses in excess of i0 tons'per acre of

may force stringent agricultural land us

action not likely to be well-received by 

landowners.

l"Amerlca's Sell and Water: Condition

and Trends", USDA, Sell Conservation Service, Lastly, huge losses of prime agricul

December 1980. lands to non-agrlcultural uses will nece

.,

. 

ir

................ ! ......
immediate action. Table 2 show's agricultural Table 3.--Agricultural land with high and

land uses in 1977 in various regions of the medium potential for being converted to

' U.S. while in Table 3 lands with potential for cropland• by selected census regions and by

conversion to cropland are shown. However, 1977• land uses (millions of acres).I

" continued losses of 3 million acres of land

j each year will be devastating to U,S. food

production and must be reduced. As with soil

i conservation efforts, if losses of prime 1977 Land Uses

, agr•icultural land continue, legislative Census Pasture Range Forest Other Total

restrictions on land use (zoning) will likely Region land land Land

come to fruition.

' West 4.0 14.2 I.i 0.3 19.6

: .

Table 2.--Agricultural land uses in 1977 in North 1 18.8 12.5 7.0 2.0 40.3

selected census regions (millions of acres), Central

South 26.6 12.2 20.6 0.7 60.1

Other ,

Census Crop Pasture Range Forest Lands Total 1 9 - 2 2 0.5 4.6 : NorthRegions Land Land Land Land in east " "

Farms ,

Total 51.3 38.9 30.9 3.5 124.6"

! West 65.8 12.6 229.3 63.2 1.4 372.3

I *About 2 million acres of "Other Nonfarm"

i North 228.6 41.6 71.i 69.1 7.2 417,6 has potential for conversion to cropland.

Central

' South i01 6 72 7 113 6 181 7 2 0 471 6

! North_ LITERATURE CITED

" 16.9 5.8 62.3 1.5 86.5

• east "Agricultural Land Data Sheet, America's" Land

TOTALS 412 9 132 7 414 0 376 3 12 1 1,348 0* Base in 1977 " National Agricultural Lands ....... Study, Interim Report 2, 1980.

_i *Excludes i0 9 million acres of "Farmsteads " America's Soll and Water: Conditions and - " " Trends. 1980. USDA Soil Conservation 

•. Service.

Barber, S.A. 1976. Efficient Fertilizer Use.

pp. 13-29. l__n_n F.L. Patterson (ed.)

SIR4MARY Agronomy Research for Food. American

. Society of Agronomy, Madison, Wisconsin.

- .Currently, the United States is a major Brown, Lester R. 1978. Worldwatch Paper 24:

food exporting country. New developments in The Worldwide Loss of Cropland. Worldwatch

•using marginal land and in technology and Institute. p. 5.

plant breeding will likely allow higher yields Fields, Shirley F. May 1980. "Where Have the

per acre if other production factors remain Farmlands Gone?" National Agricultura'l

constant. However, losses of prime agricul- Lands Study. Washington, D.C.

tural lands to erosion, fuel and fiber Kohnke, H. and A.R. Bertrand. 1959. Soll

production, and non-agrlcultural uses threaten Conservation. McGraw-Hill Book Company,

our overall food production system. Efforts New York.

through research and conservation provide some Hughes, L.B. Jr. 1971. •"A Study of the Fate

promise for Stemming these losses. Otherwise, of Carbaryl Insecticide in Surface Waters."

Norman Berg, chief, USDA Soil Conservation Unpublished Ph.D. Dissertation. Purdue

Service, may well be correct in his statement: University. pp. 1-4.

"Ten years from now, Americans could be as Hupe, S.C. 1980. The Effects of Pole-Size

Concerned over the loss of the nation's prime Black Walnut Trees on Six Forage Species.

and important farm lands as they are today Unpublished Ph.D. Dissertation. University

over shortages of oil and gasoline" (Fields,. of Missouri. p. 78.

1980).

I,,A•gricultural Land Data Sheet, America's i,,Agricultural Land Data Sheet, America's

Land Base in 1977," National Agricultural Lands Land Base in 1977," National Agricultural

Study, Interim Report 2, 1980. Lands Study, Interim Report 2, 1980.

-

130
°

National Agricultural Lands Study. 1981.

Final Report. Washington, D.C.

Pimentel, D., Ellnor C. Terhune, Rada Dyson-

•Hudson, Stephen Rochereau, Robert Samis,

Eric A. Smith, Daniel Denman, David

Relfschneider, Michael Sheppart. "Land

Degradation: Effects on Food and Energy

Resources." In Science, October 1976,

vol. 194, p. 150.

.

°

. 

t.

, | i
A CASE STUDY OF BLACK WALNUT MANAGEMENTCOSTS 1

" James E. Jones 2

Abstract.--Intensive management is required to produce

quality eastern black walnut trees. Weed control, fertilization and pruning are three important management practices

for which the component costs are contained in this paper.

The culture of eastern black walnut Table l.--Costs of primary weed control, fer-

(Juglans nigra L.) in a multicropping program tilizatlon and pruning in a large eastern

requires intensive tree care. The tree must black walnut plantation.

be .cared for from its initial placement in

the field to insure that weeds are controlled,

Soll fertility levels are adequate, and the Weed Fertilidesire.d tree shape is maintained. Control zatlon Pruning

Costs presented in this paper have been

extracted from records maintained for Sho- (dollars per tree)

• Neff Plantation which is owned by Hammons

ProductsC0mpany of Stockton, Missouri. The Materials $0.045 $0.063 ---

project consists of 480 acres with 240 acres Labor 0.013 0.038 $0.067

planted to trees. There is a total of 19,464 Equipment 0.024 0.004 0.004

trees ranging in age from 3 to 7 years. Two Management 0.008 0.010 0.007

thousand seven hundred and ninety are planted

on a 40'x20' spacing with the remainder being TOTAL COSTS $0.090 $0.115 $0.078

on a 40'xi0' spacing.

Sho-Neff Plantation is located in south-

"west Missouri near Stockton. The project is Acceptable results have been obtained by

managed for the production of conventional applying a mixture of Roundup and Prlncep in a

agricultural crops, research, and demonstra- two and one-half foot band along each s_de of

tion within the multicropping framework, the row of trees. The chemicals are applied

In Table 1 is presented costs for a one-time with a tractor mounted sprayer and side mounttreatment of weed control, fertilization, and ed boom. The boom is equipped with electric

solenoids and no-drip nozzles to facilitate

pruning, control and minimize application to crop areas.

• CHEMICAL WEED CONTROL The rate of application is 4 pints of

Prlncep 4L and 3 pints of Roundup in a soluWeed control on the project is carried tlon of I00 gallons of water. The equipment out in several manners as conditions dictate.

is calibrated to apply this mixture to one

However, the only costs to be included here acre (8,712 feet of row length with a 2 1/2'

are for primary weed control or the appllca- band on each side).

t_on of chemicals during the spring.

Time used in application of the chemicals

required 78 man hours and 51.7 hours on the

tractor. The component costs of primary weed

control are illustrated in Table I.

Ipaper presented at the Walnut Council/

NNGA Symposium, West Lafayette, Indiana,

Augus_ 9-14, 1981.

=Director of Forestry Practices and

Management, Hammons Products Company, Stockton, Missouri.

• °

132
FERTI IX ZATI ON

Individual tree fertilization has been

performed only one time since tree establishment. The application was made during late

winter and early spring of 1980. A fertilizer blend (N-P-K) of 12-12-12 was surf ace applied wi£hin the dripline of all trees at the

rate of 1 pound of product per inch of stem

diameter.

The fertilizer was delivered to various

drop points in 50 pound bags by tractors,

then distributed by hand using buckets and

calibrated containers. One hundred sixtyone (161) man hours were required to fertilize 19,464 trees with 15,470 pounds of fertilizer. See Table I for a complete presentation of fertilizer costs. _

P RULING

Pruning is necessary for most open-grown

eastern black walnut trees. To date all pruning at Sho-Neff Plantation is done with hand

pruners, lopping shears, and hand saws.

Pruning is doneprimarily in February,

March and early April. The pruning program

includes both the conventional pruning and

tip pruning. Consequently, the time element

is greater than would normally be experienced

for trees in this age and size class. However, some trees, due to their size and condition, will no longer be tip pruned.

During the winter and spring of 1981 all

trees were individually inspected and treated. The time involved was 244.5 hours. Table

1 illustrates additional costs.

SUMMARY

Producing quality eastern black walnut

trees requires intensive management. I t is

well established that weed control and pruning are essential with the jury still out on

fertilization. However, from the standpoint

of multiple crops, it is possible that we can

justify the additional expense to maintain

the plant in a high state of vigor.

There is a definite cost advantage to

• the operation of a large planting. For small

plantings which are widely separated and operated from a central location the costs

could easily double.

!

. 

!
1

BLACK WALNUT MANAGEMENT COSTS: RESULTS OF THE 1981 SURVEY

2

Timothy D. Marty and William B. Kurtz

Abstract.--Costs are described for various cultural

practices related to the management of black walnut. Average costs were obtained from a survey of Walnut Council

members to which 91 growers responded. A cash flow for a

"typical" walnut plantation was synthesized from the average costs and timing of practices reported in the survey.

Our analysis indicates that a modest internal rate of return of 6.64 percent coula be realized on all costs made

prior to the time of investment maturity. The present

net worth of the cash flow would be $519.18 per acre,

discounted at a 5-percent interest rate.

?

J Black walnut management involves many de- Management Objectives and Motivations

clslons within the constraints of the resource

base and subject to the motivations and obJec- Walnut grower characterization is based on

tives of the individual grower. These deci- management objective and motivation. Of the

sions affect the amount and timing of costs and respondents, 45 percent named timber production

4 revenues and resulting profitability of the as their primary objective, 27.5 percent cited

! program. During the summer of 1980 a mail sur- timber and nut production, resource preservai vey was conducted with members of the Walnut tlon was valued highest by II percent, and the

Council to further define some of the costs of remaining 16.5 percent selected multicropping

i Walnut management. Results are reported in or a combination of objectives. Responses to

Kincald and Kurtz (1981). the question of management motivation were dii vlded almost evenly between three major care-

: In the summer of 1981, a similar ques- gories; personal satisfaction (26.4%), finantionnaire was mailed to Walnut Counoll members cial return from timber and/or nuts (23.1%) and

_ seeklng cost information on their walnut grow- long-term investment or speculation (22.0%).

ing operations. Ninety-one growers responded. This would indicate that while a large percen-

_ Many of the returned questionnaires had unan- tage of growers manage for timber or timber and

swered questions where treatments had not been nuts, less than one-quarter do so for financial

applied, or costs were unknown. The cumulative return. Financial profitability does not apusable response, however, offers some insight pear to be a dominant motivating factor in

into black walnut management as it is being walnut management for many growers.

practiced by members of the Council.

• Resource Base

MANAGEMENT CONSIDERATIONS

' The resource base is comprised of varia-

; Responses to the 1981 survey were coded bles representing stand area and age, and land

into 50 separate variables. These fall into value and quality (Table I). Areas of walnut

four categories giving information on the stands generally appear to be small. More than

' respondents, land and timber resources, costs half of the respondents have I0 acres or less

and revenues, of planted walnut and 90 percent have 50 acres

or less. Similarily, nearly three-fourths have

less than I0 acres of naturally occurring walnut stands, with 20 percent indicating no

Ipaper•presented at the Walnut Council/ natural stands.

NNGA Symposium, West Lafayette, Indiana,

August 9-14, 1981. Most walnut stands are also relatively

2The authors are graduate research as- young. Plantation age is less than I0 years on

sistant and professor, respectively, School 81 percent of the land, with over half being

of ForestrY , Fisheries and Wildlife, Univer- less than 5-years-old. Natural stand age is a

sity of Missouri-Columbia.

134
°

I

Table l.--Summary of black walnut management data_ 1981 survey of black walnut growers.

Standard

• Category Units Responses Mean deviation Range

(number)

Acres planted acres 85 19.25 27. II 0.0 - 137.0

Acres natural acres 69 13.54 20.22 0.0 - 85.0

Site index feet/50 years I0 67.70 8.54 55 - 88

Land purchase price S/acre 74 375.11 358.58 14.0 - 2000.0

Land current value S/acre 74 1497.97 1172.91 300.0 - 6500.0

Number of trees trees/acre 76 458.82 686.30 27.0 - 4840.0

Stock cost S/tree 64 0.28 0.89 0.0 - 7.0

Site prep cost S/acre 62 27.06 67.70 0.0- 400.0

Planting cost S/acre 56 45.48 87.60 0.0- 500.0

Weed control S/acre 44 21.91 28.28 0.0- 125.0

Corrective pruning S/acre 16 15.01 16.51 0.0 - 50.0

Corrective pruning $/tree ........

Height pruned feet 33 i0.94 5.09 3.0 - 23.0

Age pruned years 28 12.53 8.34 2.0 - 40.0

Pruning cost S/acre 9 48. Ii 55.70 0.0 - 150.0

Thinning cost S/acre 6 32.00 25.81 5.0 - 80.0

Annual tax $/acre/year 49 6.81 i0.06 0.0 - 50.0

Management cost S/acre 19 20.61 26.90 0.0- I00.0

Hourly labor wage $/hour 16 4.19 I.64 0.0 - 8.0

IRespondents to May, 1981 survey.

the course of a rotation. Cost variables 

eluded in the questionnaiFe can be grouped 

• little more evenly distributed, but still only to the general areas of site preparation, 

28 percent of the stands are older than I0 ing and establishment, weed control, pruni

years, thinning costs and annual taxes.

Only I0 respondents knew the site index I Site preparation

of their land (mean value 67.7) so the descriptive estimation of land quality provides a bet- No dominant method of site preparation 

ter estimate of the type of land being used to apparent. One-fourth of the respondents u

• grow walnut. Landowners rated their land as no site preparation at all, one-fourth use

excellent (27%), good (55%), fair (16.9%) and and disc, and the remainder used mowing, c

poor (I. 1%). Most of the respondents indicated cals or some combination of these methods. 

their land was used as pasture or crops before 45 percent of the owners listed no site pr

walnut production (79%), with only 19 percent ration cost, apparently either choosing to 

indicating woods as a predecessor to walnut, place a cost on their labor, or only a sma

Two questionnaires were returned by people percentage of their land required preparati

• growing walnut on land formerly mined, due to prior management practices (i.e., p

ture/crop). Of those who did list a cost, 

Land purchase price varied widely from average value was $27 per acre.

$14 to $2000 per acre, with an average value

of $375. Price variation is largely attribu- Planting

table to time of purchase (1916-1980); over

one-half of the respondents indicated their Planting was most frequently done wit

land had been purchased since 1970. Current spade (38%), bar (18%), machine (15g) or a

, land value was estimated at about $1500 per (15%). Over 90 percent of the respondents

acre, with the most frequent response being planted seedlings. Average seedling cost 

.$1000 per acre. Weighted mean land value was $0.25 per tree, although a large number of 

not calculated. ' divlduals indicated they had received free 

lings. Average planting cost was about $

Management Costs acre. No correlation could be found betwe

planting cost and planting method. Planti

Costs associated with black walnut opera- done at an average of 458 trees per acre, 

tions are incurred at many different times in proximately a 10-foot x 10-foot spacing. 

15 percent of the planting was contracted 

iSite index represents the average height the remainder (85%) was done by the landow

(feet) a tree will grow in 50 years, at an average time of 15 hours per acre.

' 

........................ I .............
Weed control _ Table 2.--Black walnut management cash flow.

Year(s)

Weed control most often involved some corn- Category incurred Cost

bination of mowing and chemicals (49%). This ($ per acre)

was accomplished at a cost of about $22 per Site preparation 0 27.00

acre. When chemicals were used, they were

usua!ly spot applied at an average diameter of Planting stock 0 126.00

• Planting 0 45.50

abou t 3 feet. Initial weed control 0 22.00

Weed control 1-3 22. O0

Pruning and thinning Corrective pruning 3-4 15.00

It is difficult to draw conclusions rela- Pruning (10 feet) I0 48.00

Pre-commercial thinning 15 50. O0

rive to corrective pruning because of the low Pruning (17 feet) 16 48.00

response rate. Landowners appear to either

not have practiced or lack adequate records of Thinning 30 0.00

these silvicultural treatments. Corrective Thinning 40 0.00

prunin 8 usually takes place at ages three and

four years. The cost of corrective pruning

averaged about $15 per acre, and about 9 hou'rs Category Year Revenue

Of labor per acre were required. Cost is low ($ per acre)

in relation to the labor requirement because Thinning 48 520.00

over one-third of those answering the question Final harvest 60 6102.00

asslgned no cost to their corrective pruning,

apparently counting their own labor as zero.

Pruning is generally done at the age of 12

years, to a height of II feet, at an average Our "typical" one acre stand is located on

cost of about $48 per acre. Thinning was a low- to moderate-quality site capable of susindicated by only seven landowners at an aver- raining a one-third inch per year growth rate.

• age age of 19 years and cost of $32 per acre. To obtain veneer quality material over the

It is likely that because of the young age of course of the rotation, a 60-year length was

many of the stands, as noted earlier, no thin- assumed. Initial costs include site preparaning has been needed thus far. tion ($27/acre), planting stock (450 seedlings

@ $.25/seedllng), planting ($45.50/acre) and

Taxes and management initial weed control ($22/acre). Additional

weed control would be administered in years one

Two additional costs included in the sur- through three at a cost of $.22 per acre. In

vey.were annual tax and management. "Averages years three and four corrective prunings :would

are. $6.80 per acre for annual tax and $20 per cost $15 per acre. Two prunings are planned at

acre for the management cost. Most landowners age i0 to a height of I0 feet, and at age 16 to

reported paying less than $5.00 per acre annual a height of 17 feet.

tax, but several respondents indicated paying

in excess of $20.00 per acre which inflated the A precommercial thinning at age 15 costs

average value. Further refinement is needed in $50 per acre (225 trees removed @ $.22 per

thequestionnaire to more accurately determine tree). Two self-supporting thinnings are planthese costs. Future questionnaires will list ned for years 30 and 40. In these operations

the specific items to be included as management the revenue received from the sale of removed

costs, material is presumed to offset the cost of

thinning, Seventy-five trees are removed in

ECONOMIC MODEL year 30 and II0 trees in year 40.

An economic model was developed based on A commercial thinning of 13 trees occurs

the cash flows described in the preceding sec- in year 48, returning $520. These trees should

tion. This model represents a "typical" acre average just over 16 inches dbh and contain 60

under black walnut management for veneer pro- bd. ft. per stem. A current average stumpage

duction utiiizing the timing and dollar magni- price of $.67 per board foot was used to calcutude of the various management practices ob- late the value of this thinning material. Fiserved from the Survey results. In order to nal harvest of 27 trees at rotation end in year

preserve consistency within the model, land 60 produces $6,102 in revenue. It is anticlpurchase and holding costs, annual taxes and pated that these trees will average 20 inches

management costs have not been included. The dbh and yield around I00 bd. ft. per tree. A

categories of practices in the model and their current average stumpage price of $2.13 per bd.

respective costs and times of application are ft. was used to calculate the value of the

shown in Table 2. material removed during the final harvest. All

136
o

revenues were inflated at a 1.5 percent annual treatment cost averages we have presented 

rate to arrive at the future value of stumpage important, not only to each other but also 

produced. This figure, based on observable the overall enterprise. Black walnut grow

trends within the walnut stumpage market, rep- must be familiar with their treatment cost

resents the average annual price increase over a matter of good business practice.

and above all other costs and returns (Hoover

. . 1978). LITERATURE CITED

It should be noted that no revenues from Callahan, J. C. and R. P. Smith. 1974. A

nut production were included in the model, economic analysis of black walnut plan

However, as shown by Garrett and Kurtz (1981), tion enterprises. Purdue University A

substantial increases in profitability can ac- Exp. Stn. Res. Bull. 912, 20 p. West 

crue to a walnut producing enterprise by in- yette, Indiana.

cluding nut production in the management Garrett, H. E. and W. B. Kurtz. 1981. Nu

scheme, production - a valuable asset in black 

nut management. In: Proceedings of Wa

The internal rate of return (IRR) yielded Council/NNGA symposium, West Lafayette

by this "typical" plantation was 6.64 percent. Indiana, August 9-15, (in press).

This represents the average interest rate Hoover, W. L. 1978. Walnut log prices. 

earned on all costs prior to the time of in- nut Council Member Newsletter 5(I):3-4

vestment maturity at the end of the rotation. Kincald, W. H. and W. B. Kurtz. 1981. C

Present net worth (PNW) of the investment corn- of black walnut management. Walnut Co

.-" puted at a 5 percent interest rate was $519.18 Bulletin 8(1):5-6.

per acre. This is the net value of all costs

and revenues discounted back to the present

time at a 5 percent interest rate. Obviously

if land costs exceed $500 per acre the investment, as structured here, will not yield a 5

. percent return. This finding is consistent

with returns to the "basic" black walnut enterprise model developed by Callahan and Smith

(1974).

CONCLUSIONS

Investment in black walnut as structured

for our "typical" plantation yields modest returns. Our analysis does show that walnut is

being managed in a profitable fashion. Treatment costs involve only a very small portion

(less than 10%) of all costs of the walnut enterprise. These expenditures yield substantial

benefits through increased size and higher

quality material at harvest.

Increased returns to black walnut management can be achieved from various factors not

specifically addressed in this analysis. Management for nut production and/or the adoption

of a multicropping management scheme both have

the potential for enhancing the profitability

of the basic wood producing enterprise.

Obviously, the plantation as constructed

is "typical" only in the sense that it represents an average based on the various management experiences of a group of walnut growers.

It should be kept firmly in mind that the samp!e group has widely divergent management objectives and motivations as well as different

•socioeconomic characterlstlcs. Nonetheless,

this should not deter from the usefulness of

our analysis in describing the responses to

l the 1981 The relationships of the survey.

I 

k
. A CRITICAL LOOK AT THE EXPECTED RETURN ON =

i

• INVESTMENT FROM PLANTING BLACK WALNUT SEEDLINGS

By Dwight R. McCurdy 2

Before investing money, time, and land in 5. The risks and uncertainties involved

plantln'g black walnut seedlings several fac- in growing walnut trees.

tors should be considered by anyone placing a Table I contains the estimated costs and

positive value on their money. First, a person returns per acre for an hypothetical walnut

should realize any money spent purchasing, investment. This "basic model" of a black

planting, and caring for walnut seedlings has walnut plantation was developed by Callahan

a greater cost than the out-of-pocket expen- and Smith in 1974. It should be recognized

ditures for the seedlings. To illustrate, if these costs and r:eturns were developed for a

$i00 are to be spent in purchasing and planting specific site and were based on several

seedlings , the owner before making the invest- assumptions. For example, sites vary in

ment has at least two alternatives: suitability for walnut timber production.

(I) putting the $I00 in a coffee can and The rate the trees grow and the survival rate

burying it, and (2) placing the money in a for individual trees will vary between sites.

relatively risk free federally insured These two assumptions are major factors

savings account. Assuming 40 years passes, affecting the profitability of the investment.

the amount in the coffee can (assuming it can Therefore, as a minimum a forester should conbe found) Will still be $i00. However, the duct a si_e analysis to determine the expected

money in the savings account would be $1,498 growth and survival rates relative to the

if the bank paid seven percent compounded appropriate silviculture treatments needsd

annually. To be completely accurate, the in- for walnut timber production.

vestor would only have $i,048.60 after taxes

if he was in the 30 percent income tax In critically analyzing the applicability

bracket Therefore, the person planting the of Callahan's basic model (for an hypothetical

walnut seedlings should have at least walnut investment) for other walnut investment

$i_048.60 after selling the trees and after opportunities we will first discuss Item One,

taxes (assuming no other costs). The actual Table I, land cost. It is well accepted that

amoUnt the walnut investor will receive from land values vary widely thereby making

: his investment will depend on many factors-- generalizations about the return on investment

some of which are listed below: from a given site suspect. However, it is

recommended that land values not be included

i. Th_ amount of money for which walnut in walnut investment analyses. Land in itself

• trees can be sold at maturity; is an investment and appreciates in value

regardless of use as long as its character

:2. The additional monetary costs and isn't degraded. This appreciation in land

' returns resulting from growing the value may be at a faster rate than the rewalnut trees; turns from the land's use thereby making the

combined investments of land and land use

3. Other costs and returns (externall- appear better than the investment in land use

ties) that result to the investor alone. It should be pointed out this situafrom growing walnut trees; tion is nearly i00 percent valid relative to

forest production investments. For example,

4. The opportunity for additional land values may increase at a rate of i0 perinvestment alternatives; and cent compounded annually in comparison to less

_ than 5 percent obtained from monies invested

specifically in timber production. One negaipaper presented at Walnut Council tlve aspect of leaving out land costs (or

Annual Meeting, Purdue University, West value) is that holding or opportunity costs

Lafayette, Indiana, August 13, 1981. of the land over the investment period are not

" accounted for in the analysis.

2professor of Forest Economics, Department

of Forestry, Southern Illinois University,

Carbondale, Illinois.

138
° ,

The second expense item in Table I con- Not only should the silvicultural p

rains the initial establishment costs other scriptions vary between sites (investment

than seedling and planting expenses. These situations), the costs of accomplishing 

expenses could vary from nothing to a rela- specific task such as pruning will differ 

tively large amount depending on the condition tween investors. For example, one landow

= of the land. For example, fencing to prevent may already own the equipment needed and 

grazing by cattie may be necessary, might also have the skill to perform the 

while on the other hand, another investor 

The third expense item, cost of the be required to hire the complete performa

planting stock, is a critical item since it of the task. More specifically, one pers

depends on the spacing between seedlings and may own "old" equipment resulting in a s

in turn spacing dictates the number of seed- capital investment while a second person 

lings per acre. Spacing also affects (i) the have "new" equipment with a comparatively

silvicultural treatment costs, (2) expected higher capital investment but lower opera

growth rates, and (3) quality of the harvested costs.

o _ stem. For example, spacing may vary 'from

i0 x i0 feet (435 trees per acre) to 40 x 40 A more important consideration when 

feet (27 trees per acre). , culating the expected expenses is the fa

expenses occur in the future requiring t

The fourth expense item, planting costs, vestor to be a futurist. The model as p

can also vary widely between investment oppor- by Callahan specified no increase in silv

tunities. F0r example, one site may be ture treatment costs for like tasks there

suitable for machine planting with no site assuming that today's expenses will remai

preparation expenses while at the other ex- parallel to inflation in amount. However

treme another site may require hand planting recent history has demonstrated silvicult

and then only after bulldozing a residual treatment expenses increase at a greater 

stand of undesirable trees, than inflation.

The next seven expense items are speci- Expense item 12, administrative cost

fled by a given silvicultural prescription such as taxes, insurance, etc., which oc

which should vary with site conditions. As annually seem relatively small but when

mentioned earlier, a forester should be con- accumulated, these expenses result in a 

sulted to determine the alternative silvicul- proportion of the total. In fact, a smal

rural treatments that will be needed for the variation in the amount of administrative

specific site being considered. For example, expenses can significantly effect _he pro

Callahan selected his hypothetical treatments bility of the investment.

from the following alternatives:

The final expense item in Callahan's

Method i. Completely disk the planting basic model, self-supporting thinning, wa

area and control subsequent placed at zero costs under the assumption 

weed growth by the application should be done with revenues from fence p

of chemicals. Here again, if there is no market for fen

posts, firewood, etc., the profitability 

Method 2. Completely disk the planting the investment is greatly reduced. Furth

area and control subsequent more, if proper thinnings are not perform

_eed growth by cultivation, the length of time to final harvest is si

nificantly lengthened. The time period b

Method 3. Completely disk the planting planting and final harvest is one of the 

area and limit subsequent elements in determining the size of the 

weed control to spots or on the investment.

strips around the planted

tree with weeds between On the other side of the ledger are 

treated areas controlled by revenues generated from the walnut invest

t mechanical means such as The amount of revenues is dependent to a 

, mowing or cultivation, extent on the quantity and quality of tim

| •

I available for thinning and harvest. But, 

i Method 4. Completely disk the planting mentioned earlier, timber availability is 

i area and limit subsequent weed turn dependent on site conditions, spacin

control to spot weed control silvicultural treatments and environmental

• around individual trees using conditions (climatic, disease, insect, et

' chemicals, over the life of the treatment. All thes

4

can vary dramatically for different inves

opportunities. For example, survival of

' 
planted seedlings to maturity can vary from 1. All returns should be after taxes

less than i0 percent to over 80 percent, have been deducted. Forestry, beAlso, the volume per acre at 50 years can cause of capital gains, has an

vary between 2,000 and 16,000 board feet advantage relative to land uses

depending on the site and original spacing, returning annual revenues.

Also, similar to expenses, most, if not 2. The rate of returns should be adall, revenues occur in the future thereby justed for risk and uncertainty. For

•making realistic estimates difficult. For example, the probability of not reexample, the price received from the walnut ceiving the estimated future revenues

timber varies significantly with the is generally greater with forest infollowing: vestments in comparison with most

° other land use investments.

i. The form in which the timber is

sold; such as (I) on the stump, 3. The externalities from the invest-

(2) as logs at the logging site, ments should be compared. For

or (3) as logs delivered to the example, forest investments often

buyer; , enhance the recreation values received from a tract of land.

, 2. The market conditions at the time

of the sale. The timber industry 4. If the investment is to be continued

is very cyclic relative to prices by heirs, what is the probability

_" since the demand is derived from the they will have the same time

• demand for a finished product of preference for their money as the

! much greater relative value; and original investor and an. identical

interest in forestry or natural

3. The product into which the timber resources. The rate of change in

i will be processed; such as lumber land ownership on the average indi-

| versus veneer. Veneer walnut is the cates the above probability is very

• only product having sufficient value small.

to even consider possible investment.

I If an export market is available the

• chance to receive favorable veneer CONCLUSION

prices is also enhanced since export

prices generally are much higher than When analyzing the potential return on

• domestic prices. • investment from black walnut timber production,

site and time specific estimates are needed

_- In Callahan's basic model, prices were relative to the expected costs and returns.

assumed to remain parallel to inflation as Generalizations from data published from

indicated by using 1974 prices. However, other sites and ownership conditions can lead

unlike expenses, prices over the recent past to significant differences. In most cases,

have paralleled inflation. For example, the assistance of a consulting forester is

_ average walnut prices in Illinois between advised.

1967 and 1976 increased 83 percent and the i

•wholesale price index also increased 83

percent (McCurdy, 1977). REFERENCES

When determining the return on invest- Callahan, John C., and Robert P. smith. 1974.

ment, the present or discounted value of all An Economic Analysis of Black Walnut

• , expenses must be equalled with the present Plantation Enterprises. Purdue

" value of. all revenues (Column 5, Table I). University, Agricultural Experiment

The discount or interest rate that results in Station Research Bulletin No. 912, 20 p.,

expenses equalling revenues is the rate of West Lafayette, Indiana.

return on investment. For Callahan's basic

o" model, with land values being eliminated, the McCurdy, Dwight R. 1977. Illinois Timber

rate of return was 6.5 percent. Prices 1967-76. Southern Illinois

University, Department of Forestry

: It is this 6.5 percent that the investor Publication, 39 p., Carbondale, Illinois.

Should compare with his alternative opportunities such as placing his money in a can,

savings account, etc. However, to be rational

the following adjustments must be made to the

return on investments being compared:

• 140
o

Table I. Basic Model of a Black Walnut

Plantation Investment, Per Acre.

11) 

o 1-1. o

0 1-_ rt N)

Z M I-_

= M I--; _"

Item _ _ _ v ,

J _ EXPENSES :

i. Land 0 , 350 N.A.

2. Initial Establishment 0 70 70

.." 3. Pl_ting Srock 0 30 30

4. Planting 0 25 25

5. Weed Control (Culti- 0 35 35

vation & Chemical)

6. Weed Control (Chemical) 2 15 13

Corrective Pruning i0 8

7. Weed Control (Chemical) 3 15 12

Corrective Pruning i0 8

8. Weed Control (Chemical) 4 15 ii

Corrective Pruning i0 7

9. Pruning to 8 feet 8 90 54

I0. Pruning-50 select 13 50 22

t.p.a.

Ii. Thinning 15 0 --

12. Annual Charges 1-50 I0 144

• 439

.-.....

REVENUES:

13. Thinning 25 50 i0

14. Thinning 35 200 22

I 15. Final Harvest 50 9500 407

I 16. Terminal Land Value 50 350 N.A____.

, 439

!

Source: Callahan and Smith, 1974.

/

. 

........ Ill ....... I I I_ . A ....

Im
WALNUTRESOURCE: AVAILABILITY AND UTILIZATION

Presented at the NNGA/Walnut Council Joint Meeting

.. Purdue University, West Lafayette, Indiana, August 13, 1981

Larry R. Frye, Executive Director

' Fine Hardwoods/American Walnut Association

Indianapolis, Indiana

. Abstract -- Walnut Resource: Availability and Utilization

,

High quality black walnut trees for lumber, veneer, and gunstocks are still in a somewhat short supply. The outlook for

their demand is excellent. Current hardwood forestry programs

need to reach more landowners; and hardwood forestry education

must become more effective to insure adequate supplies of these

valuable raw materials for the future. Utilization of the

entire tree is likely to continue to become a reality as the

use of wood as an energy source increases.

• When you ask a member of the industry today recognizes the necessity of landowner profits

about the walnut resource, he is likely to and knows it can and should result in more

tell you "goo d walnut trees, or for that matter, management. Unfortunately, all too often the

good trees of any species, are hard to find." landowner, or his or her heirs immediately

sold the timber and failed to return any of

In 1966 at the Walnut Workshop in Carbondale, this money back into a forest management pro:

Illinois, Steve Boyce started his speech with gram. Often with heirs, it is strictly a

a statement "large diameter, high quality case of raping the land for whatever dollar 

Veneer and sawlogs - these are the walnut value they can derive.

timber products in critical shortage." In the

abstract written for a paper presented at the As we look into the future, we feel that

1975 Black Walnut Symposium, Jim Blythe said, walnut will continue to be readily available,

; "rising prices with fluctuating demand indi- but the quality problems will continue. The

cate a scarcity of high quality walnut, a challenge to foresters and landowners is alneed. for more efficient and complete utiliza- most frightening. Somehow, we have to motivate

tion of the walnut resource, and the necessity the people who own the land growing hardwood

for reducing costs in domestic manufacturing timber to do a much better job of managing

of walnut products so they can remain competi- the trees. For nearly a hundred years we

° tire With substitutes and foreign products." have heard the cries from the wilderness that

. we are going to run out of timber and that

Here we are, not quite ten years later, and some species will become extinct. We know

we still have most of the same problems. The this can happen, but we also know there are

buyer of walnut timber, for nearly twenty years tremendous opportunities to make sure that

has had to buy trees that are smaller in both this does not happen.

diameter and in total height. He has had to

buy trees with more pin knots, frost cracks, In his report to the Indiana State Board of

spiral grain, and other factors that reduce Agriculture for year 1880, Professor C. I.

the yield" from the logs. At the same time Ingersoll of Purdue University indicated that

competition for the raw material has forced about 85% of the black walnut resource in the

the cost of logs to skyrocket upwards. State of Indiana had been disposed of. Pro-

- lessor Ingersoll warned the people of Indiana

The demand for black walnut has helped motivate not to destroy their forests. To quote him,

timber management by allowing for more profit "if the cornfield is destroyed, it can be

on the part of the landowner, and the industry restored in a single season, but when the

142
°

.

forest is destroyed, a hundred years are re- if we are going to continue to have adeq

quired for its full restoration." To continue timber supplies in America.

from Professor Ingersoll, he stated "go with

me if you please to some of the countries of The other part of my assignment is to ta

Europe and Asia, and read there the silent about utilization. I believe that we h

admonishments stamped by the absence of wood- come a long way in America, particularly 

lands for centuries." the softwoods and we are doing quite we

the hardwoods, at using almost the entire 

The lessons are well documented, unfortunately

only a few eyes have seen them. It is time in At the mill level, the progress is appar

America, particularly here in the midwest, when You rarely see the piles of bark and saw

we stand up and admit that we are not doing the In most cases you do not see the scrap 

_ job in hardwood forestry. We can kid' ourselves was once taken to the backside of the m

and we can Say that we are growing more timber and bulldozed over the hill. We are no

thanwhat we are using. We can justify reasons using the bark for landscape and mulch, 

for land clearing. We can bow dow_ to the we are not burning it along with the sa

interests of corn, soybeans, and other row and the other edges and trimmings as an

andpasture crops. We can excuse the utility energy source for the mill. We are wor

right-of ways, and the home builders and the harder to find markets for all grades of

real estate people for taking our tracts of hardwood lumber and veneer. At the Asso

timber and making them into the finest, most tion level, we have for many years been 

expensive homes in the area. We can come up volved in a character marked program to 

with many excuses, but if you are satellited mote the use of all the grades that are 

with the responsibility of finding timber to veloped in the manufacturing process.

operate a mill Monday through Friday, then

you know from your own experience and in your In the woods we still have work to do. 

own heart that the course we are on today true that we find a lot of tops, limbs, 

will not lead us to a land of plenty, unmerchantable trees still left in the w

This material will in time be used. We 

As we sit in meetings, we hear how the wilder- currently seeing interest for fuelwood. 

ness and preservation people are demanding believe the day will come when the indus

that more acres each year be locked up,'never will have a crew to chip this material 

to be managed again for multiple-use purposes, take it back to the mill to add to the 

Those of us in the timber business and many of source. We should all be thankful for 

you in the forestry profession, for the most research currently underway in this area

part, do not go along with these theories.

Yet, we sit in these same meetings and often To the growers of the resource I can say 

do not speak up, and we do not move forward the outlook is good. Raw material prices 

with programs of our own. We seem to always taken only one direction in recent years, 

be defending our actions. If the preservation that has been upward. Granted it has cy

groups continue to insist on having single - but the general trend is upward and I d

purpose management areas set aside, then we see how it can go any way other than up 

probably should demand that single-purpose now on, which is good news for you beca

areas be set aside for timber production and you can make forest management investments

timber prOduction only. It has been said with the confidence of a good return on 

many times that the best defense is a good investment.

offense. We have got to get busy, if we are

. going to remain in this ball game at all. Whether the industry can keep up with th

money market and the high prime rate is

Fortunately, it is not too late. There is questionable. Whether or not anyone can

• still time to turn hardwood forest management keep up with the prime rate is questionabl

in America around, but I challenge all the This is one of the most serious problems

landowners, all .the industry, all the individuals facing the industry. With the high prim

working in this field to stop fooling around rate and the business slow demand for t

• and get down to the business at hand of prac- is likely to soften slightly. So it is 

ticing those forest management techniques which your advantage to see the prime come dow

are already known. The day may come heaven Hopefully, at the same time inflation w

!

forbid, when we will have to legislate the be lowered, and this country will return 

practices that we know have to be incorporated a somewhat stable and normal economic si
.

] tion again.

I am optimistic that the future for hardwood i

lumber and veneer is excellent. We all know

( that the children of the population explosion

_. that Occurred in the late 1940's have now

moved into the. prime buying age bracket. They

i will be buying homes and they will be filling

__ those homes with furniture, which means more

demand .for your timber products'. With all

-Other factors being normal, we expect excellent

business throughout the 1980's. By the time

i the war babies move ,on to an older age bracket,

i where they may not buy so much, we will be

more into a worldwide market, which again will

I brighten the prospects and opportunities for

the timber growers of the midwest.

!

1

1

i

4 '

1

a

.r.

. . .

_ " ,

T

=

,

144
.

BUYERS PERSPECTIVE ON MARKETINGWALNUTTREES

Presented at the NNGAIWalnut Council Joint Meeting

Purdue University, West Lafayette, Indiana, August 13, 1981

meal E. Jennings, Timber Buyer-- Forester

Missouri Valley Walnut Company

Lincoln, Nebraska

, =.. ,

Abstract -- Buyers Perspective on Marketing Walnut Trees

Marketing walnut timber is a business transaction between

a willing buyer and a willing seller. The value the seller

receives is the approximate difference between the end

value of products produced from the tree/log mix involved

in the sale and all related costs and profit. The stumpage

value is determined by a buyer who estimates value based

upon evaluation o£ location, size, and defects

• After a sale, trees are cut, bucked into logs 4) Dollars Per Tree--The seller sets a doll

and transported to a mill for processing or value per tree standard which the buyer

re-sale. The movement from landowner to mill must meet, eg. The timber sale must av

may take several routes: $100 per tree. The buyer must then pay 

the basis of $100 per tree cut (poor pr

Landowner_._ Independent._+ Company__ Mill rice, leads to high grading).

buyer buyer

5) Grade and Yield--The buyer cuts, bucks,

• Landowner__ Company buyer.__ Mill sca'lesand grades logs. The price paid 

the seller equals the scaled volume by 

Landowner or Independent buyer__ Mill times the agreed upon price per grade.

6) Dollars Per MBF--The buyer cuts, bucks 

Timber sales are transacted in many ways, but scales logs. Payment is based on agree

in all cases the timber buyer pays for a upon price per thousand board foot. Th

• given number of trees. The most common selling seller and/or third party may assist in

methods are: scaling logs.

1) Lump Sum Sale--On a given piece of land the 7) Auction--The buyers are given an opport

buyer pays for all usable timber within to review marked trees or the sale area

given agreed upon constraints, eg. All and at a given time and place an auctio

- walnut over 16 inches, all merchantible held (rarely done).

' red oak, and hackberry over 14 inches.

. 8) Tel,eph,one Auction--The seller calls pro

2) Sealed Bids--This method is essentially the rive buyers an_itries to manipulate bid 

.i same as a lump sum sale, except sealed bids by playing buyers against each other on 

• are submitted by buyers. Bids are opened individual basis. This is a common pra

by the seller at a given place and time. rice after the seller has accepted origi

bids (sealed or otherwise). Often the 

3) Percentage--An agreement between the land- quoted in the "auction" are inaccurate

o-wrier and buyer" the buyer cuts the trees

and then sells to one or more company STUMPAGEVALUE

buyers. The buyer and seller divide

proceeds based upon predetermined per- VALUEEQUALSWHATSOMEONEWILL PAY. No wa

centage of gross receipts, buyer (at least for very long) can consisten

invest more in a purchase than he receives 

..

.
°

return. All values are based, in the final vestment. On the AVERAGE, trees from a given

analysis, upon the market value(s) of products spot (area of origin) have a different value

produced by the mill. This market value(s) than trees from another spot. For ease of disminus all transportation, processing, and met- cussion I have separated area of origin into

chandizing costs plus a reasonable profit es- four classifications.

tablishes a given average log value. This is I) REGION--Is a very general classification.

the competitive log value paid for a given log Different companies/buyers will use differdelivered to a mill. This value minus a cutting ent boundaries. In the western part of

andhauling charge, minus transportation fees the walnut range, northern and southern is

(truck or rail), minus buyers expense/profit often used and the boundary is approximately

equals the stumpage value, an east west line from St. Louis to Kansas

City. Northern logs (on the average) are

The stumpage value of walnut trees is a factor better than southern logs.

of _volume (board feet), grade and value per

board foot per grade. 2) DISTRICT--Refers to a general area within

' a region. I think of a district as the

The value of lumber logs is based upon size approximate boundaries in which a buyer

(diameter and length), quality and often usually operates. In my case, this would

general area Of origin. All three factors re- be western Iowa and eastern Nebraska. There

late back to the kind and quality of product is a considerable difference between the

produced. The higher the quality (end value) average value of logs coming from different

the greater its value to the mill. For example, districts.

larger is better than smaller, cleaner straight

is better than defective crooked, and northern 5) AREA--Refers to units within a District.

is better than southern.. Hence, a large, Host buyers will consciously or unconsciously

. clean, straight northern log is worth much differentiate between areas. I have about

more than a small, defective, crooked southern ten different areas within my District. On

log. the average, trees from different areas

have a different value. I pay a different

The value of veneer logs iS likewise a factor price for Veneer logs (lumber logs remain

of size (diameter and length), defects, area constant) depending upon area. I do not

of origin (general and specific) and a rather have a good explanation for this difference,

undefinable buyer evaluation of wood quality but assume it relates to some interaction

(Color, grain, pattern, etc.). I do not know of soil, moisture and/or other environmental

of any veneer log grading system that can be or genetic factors which affect quality.

applied to the value of veneer logs. For example, I commonly pay 5 times more for one log 4) PAST HISTORY AND SETTING--Any abuse suffered

than another even though both would fall within in the past by the tree lowers its quality,

the same general log grade. This differential Grazing (type of critter and intensidy),

is due to my evaluation of what dollar value fire, herbicides, and any type of human or

the log will ACTUALLYYIELD after processing, natural injury (equipment/storms) have a

negative affect on the health/vigor and

It should be apparent by now that there is no quality of the tree. The specific setting

answer to the question "What is a walnut tree of the tree, eg. contigious timber stand,

worth?" The question is much like asking "Wnat narrow bands of trees along field or streams,

is a used car worth.*" There are some ex- or trees in proximity to humans has an affect

ceptiOnal used cars (Elvis Presley's gold on tree quality. On the average, trees

plated cadillac) just as there are some ex- located within contigious stands are of

ceptiona_ walnut trees. One must recognize better quality than those in narrow bands

that no value for any commodity, walnut trees and both are better than those in rural

or used c.ars, can remotely be based on the or urban homesteads.

extremely rare individual, but rather has to

be based on the average of what really exists. SIZE

AREA OF ORIGIN Without exception, all other variables being

equal, larger diameter logs are worth more per

All timber buyers and/or walnut companies have board foot than smaller diameter logs. One

a tremendous backlog of experience (successes would think size is the one constant in deterand failures). As with most businesses, they mining value, but log rules and scaling methods

use this experience as a basis for future in- differ.

1.46
The walnut industry uses the Doyle Log Rule and anticipate fewer low side limbs, early shed

bases scale on" of limbs, and fewer internal limb defects.

1) Length to the nearest foot. Nine feet eight

inches is nine feet. Lengths on veneer logs Sapwood width is also a reliable indication 

are extremely important. A log bucked at log quality for essentially the same reason

8'1" has a drastically different value than as taper. Narrow sapwood indicates good l

the same log bucked at 8'5". Critical quality. The bark is a good external indilengths relate to the requirements of the cator of sapwood width. One should note t

ultimate use of produced veneer. The same through bark, taper and width of sapwood t

critical lengths apply, to standing trees, buyer tries to determine cleanness of log

- Anyone who appraises or evaluates trees (lack o£ internal limb defects). Under pr

and guesses at the length of veneer logs plantation or native stand walnut manageme

_ does a disservice to all concerned, one will often have poor bark characteristics

(to the buyer), average taper, and wide sa

2) Diameter inside the bark (DIB) at _he small- wood. As noted, these factors are not deest point in the log. Where DIB cannot be fects, but indicators of defects. Buyers/

directly measured (standing tree, log cut mills are interested in clean wood. My ad

at a limb swell, or log with crotch at small to owners is to properly prune trees to ge

end), the DIB=circumference x 0.28. This clean wood and take periodic photographs t

formula takes into account bark thickness, convince future walnut buyers of the quality

It is not always exactly accurate, but is of your product. _

very close. For logs/trees over 100 inches

in circumference (29 inches DIE and larger), LIMB DEFECTS

the formula is circumference x 0.30=DIE.

, There is a difference between limbs and lim

I have on several occasions been told that log defects. A limb is external to the bole o

buyers are cheating people by using the Doyle tree. A limb defect _s internal to the bo

Log Rule because it underestimates the actual of a tree. A buyer only concerns himself 

board footage derived from small diameter logs. the internal defects. ANY indication of a

limb defect is evaluate_"_he same as an ac

one cannot cheat anyone based on the type of log limb. I am often amused that many people

scale used. You can only cheat someone if you believe pruning limbs off a tree immediately

pay less than a fair value for the tree. It raises the value o£ the tree. In fact, la

• really does not matter what log rule is used. limbs removed from larger trees often lowe

The actual price paid for a given log is in- value due to decayldiscoloration/staining.

dependent of the log rule used to estimate The existence of a limb guarantees the pre

volume.. For example" sence of a limb defect, but the absence of

limb does not preclude the existence of a

Log Rule Lt. Dia. BF $/BF Total limb defect.

Doyle 8 14 50 0.55 $27.50 HOLLOWS

International 1⁄4" "8 14 65 0.42 27.30 I would hope that everyone recognizes a ho

tree greatly decreases in value. The hollo

Scribner Decimal C 8 14 60 0.46 27 60 normally precludes any veneer and limits i

value for lumber. The timber buyer is not

DEFECTS often fooled (with experience some trees j

. lookhollow), but I do not know any buyer w

Bark characteristics, taper and width of sapwood does not occasionally get fooled. The rea

i are not actual defects, but are reliable indi- trick for a buyer is determining the size 

i cat0rs of wood quality. "Good or bad" bark extent of the hollow. Sometimes the hollo

I

_! characteristics are impossible to describe or peaks out rapidly and sometimes it runs a

demonstrate. They also vary from area to area. the length of the tree. You know you've g

Most walnut buyers rely heavily on bark char- a problem when you stick a saw into a tree 

• acteristics to determine value. " mice come running out, but you're in real 

• . when a skunk, opossum, or racoon scampers 

Taper is an indication of the first few years of In all the trees we have cut, I have not 

height growth. Rapid initial height growth (less anything that conflicts with the research 

taper) normally indicates heavy competition when Dr. Alex Shigo's research concerning tree

trees are young. With competition one would wounds and compartmentalization.

°
LIGHTNING

Lightning is one of the worst injuries a tree

can sustain. It seldom kills the tree, but

often opens the whole length of the bole to

decay and discoloration. Even if decay has not

severely progressed, it will almost always

cause a ring shake. One should sell a light,

ning struck tree as soon as possible.

.

METAL

Timber buyers often feel paranoid about metal

in'treeS. It seems people go to great lengths

to nail fences, insulators, signs, deer stands

and g0od-luck horse shoes to trees. Besides

the obvious problems associated with damage

to mill equipment, oron oxidizes and stains

the wood a blue/black. Metal stain extends

both above and below themetal site, which

further deteriates the value.

BIRDPECK -- WORMS

Birdpeck and worms are hard to spot in a standing tree and are often difficult to see in a

cut log. Both are severe defects, especially

in veneer. One worm hole essentially lowers

the veneer value the same as a limb defect.

Birdpeck and worms are primarily a southern

logproblem but a small amount of peck and

' worms are found in northern logs. 

1.48
COST SHARING INCENTIVES FOR BLACK WALNUT MANAGEMENT I

Robert W. Koenlg 2

Abstract.--Cost Sharing Incentives have been

beneficial in encouraging black walnut management and

where common sense is applied will yield reasonable

returns on both the public and private investment. This

paper presents a "Dirt Forester's" Common Sense approach

on how cost sharing practices might best be applied. No

attempt is made to give exact cost figures or scientifically

prove what is eluded to. It is just 19 years of experience

and observation speaking!

It is indeed a pleasure to return to my practices involving black walnut leadln_ 

old Alma Mater and be able to impose a little way. In fact black walnut tree plantlng

practical, Dirt-Forestry philosophy on such a practices showed an internal rate of ret,_

-distinguished group of nut growing, nuts as (IRR) of 14%, and black walnut timber _tan

you all are. The subject of cost-sharlng improvement practices showed an IRR of 21 

incentives is one that has been near and dear

to my heart for the past 19 years, since I The first federal cost-sharlng pract_

• havebeen associated with professional Forestry specifically taylored, for black walnut ln

work in Indiana. Indiana were initiated in the early 1960', 

ACP practices A-7(B) for establlshln_ a _t

Let me say from the start that I am a of black walnut trees and B-IO(B) for l.-:

"Die-Hard Conservative" that believes in as a stand of black walnut trees. Althou_h w

little Governmental intervention in private have lived through REAP (Rural Envlron=en:d

affairs as is absolutely necessary to insure Assistance Program) in the early 1970's, 

the preservation of our free enterprise system have graduated to FIP (Forestry Incentive.

• of economics; but let me also make it crystal Program), and have changed practlces nu=be

clear (that based on my experience) little or several times, we still have the two basl:

no forestry work would ever have been started practices: Tree Planting and Timber Stanu

in the private, non-industrial forests of ImProvement with their several component p

Indiana without the ACP original cost- sharing

program and the stepped-up application of Baslcally all cost-shared forestry pr

forestry practices because of the addition of whether for walnut or any species or speci

the FIP cost-sharing program in 1974. This is mix can be divided into one of two categor

not to say there could not have been another

way to stimulate _hese badly needed activities. The first category includes those pra

But from recent studies conducted on the cost which insure the establishment of new blac

effectiveness of the first year of _IP practices walnut stands such as: site prepareatlon, 

(1974) throughout the United States-, it planting, firebreak and access road establ

certainly appears that most federal cost- and initial weed control.

' sharing has been fairly cost effective with the

The second category includes those pr

which improve the quality and quantity of 

ipresented at the NNGA/Walnut Council walnut products grown such as: corrective

Joint Meeting, Purdue University, West Lafayette, pruning, side-limb pruning, pre-commercial

Indiana, on August 13, 1981. thinning, crop tree release and maintenance 

2Assistant State Forester, Indiana firebreak and access roads.

Department of Natural Resources, Division of

Forestry, Indianapolis, IN. Undoubtedly, you have all been told 

3"Timber Yield and Financial Return black walnut is very site specific in its

Performance of the 1974 Forestry Incentives requirements for surviving and maintaining

Program", Mills, Thomas J. and Darla Cain, reasonable growth rates. That has been pr

Research Paper Rm-204, Rocky Mountain Forest unequivocably by the many plantation failu

and Range Experiment Station, U.S.D.A. that have occurred over the past 25 years 

.
before, because they were planted with no c. Bush hogging followed by

J consideration-for soil texture, soil depth, herbicide application as

rooting limitations, available soil moisture, above--use where small

slope aspect, slope percent, accessibility for trees and shrubs are present

i protection and cultural treatment, etc, etc. and likely to be competive. This same fact of "site specificity" affects

i the success of not only walnut planting but d. Bulldozing and root raking--

also all other cultural practices. For it does use only where larger trees

notreereasfroonabl m unde esgiorab od leto try compettoitrioelease n such aaswalnut weeds, problem (3" DBH and and up) only arewherethe site

shrubs, lower-valued trees or vines, if the quality is excellent--this

i walnut wrong site' tree-being This would releasedbe isa wagrowing ste of onboththetime ieconom s tooically expensive justiftoiedbe on

and money for the growth response could never anything less than the best

pay back the investment made. areas.

Assuming that site is not a problem, then 2. Tree planting-includes the cost of

_,the proper sequence of component practices that purchasing seedlings.

go into establishing a stand of black wal_ut

trees should be as follows: a. Mechanical tree planting--

best for larger plantings

I. Site preparation--this might be and areas that are level to

any one of the following treat- gently rolling and easily

ments or a combination of treat- accessible. Pre-emergence

ments to get the land ready for herbicide can normally be

the actual planting of trees, applied at the same time

It is up to the responsible further reducing costs.

forester to determine the needs

• and make an estimate of cost per b. Hand planting-small plantings,

•thousand trees to be planted steep slopes or areas withusing such treatment. Site prep- poor access for motor vehicles.

aration can run as low as just a

few dollars per thousand trees 3. Pre-emergence herbicide or initial

planted to as high as several weed control absolutely necessary

hundred dollars per thousand if the plantation is to be successful.

_ trees planted depending on the This must be applied during or

condition of the land and what immediately after planting and then

ii " needs to be remove to make it at least once every spring for the ready for planting, first five years Some of this may

_! be eliminated by proper

• a. Plow and disc firm--good interplanting or preplanting of

.... for level to gently rolling such species as Autumn Olive,

-_ old fields--costs vary European Black Alder, White Pine or

_ according to custom rates Black Locust. Almost no corrective

_ charged locally, pruning is needed if interplanting

_:_ . is used

:_r

_ - b. Herbicide application in

v_.- , bands at least two weeks 4 Walnut as an interplanting, with

before planting--good for pre-emergant herbicide spot sprayed

o_ preparing old sod fields around each interplanted walnut--

_ and weed invested areas good for rough sites, slightly

_i _ . where it is too steep to doubtful landowners, etc.

plow and no brush or trees

are present to complete, a. First plant white pine on

Either Dowpon or Roundup 10'xl0' spacing and let it

• has been used successfully, capture the site (3 to 5

All label recommendation years).

should be followed in

handling and application b. Then interplant walnut when

rates, the pine have their heads

above the major weed competition.

150

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°

Already, one can see that establishing 8. Non-commercial thinning-means 

black walnut is expensive and labor intensive of trees removed is less than 

and not for those who believe: "you just stick cost.

the damn things in the ground and let 'em grow'"

That just won't get the job done. If you do a. For plantations follow t

not intend to take care of the planting, please, Forest Service Guide "Qui

do not plant black walnut' Reference for Thinning B

Walnut" prepared by Burl

Assuming you are bound and determined to Ashley of Northeastern A

go on with it (planting and growing black State and Private Forestr

walnut), then the rest of the steps fall under Morgantown, W.V. and Rich

the category of Timber Stand Improvement and Schlesinger of North Cent

should take you up to the time when a Forest Experiment Station

commercial thinning is possible: Carbondale, IL and publi

_ by the North Central Fore

5. Fencing to keep livestock out of the Experiment Station at St

plantation or out of a stand of This uses the Crown Compe

native walnut trees is another Factor (CCF) to determine 

prerequisite for growing walnut or to thin both for veneer-s

any forest product in Indiana-- production and for nut-lo

this only includes interior fences production.

and no cost sharing is allowed on

boundary or road fences under b. For native or natural bl

either ACP or FIP. walnut stands, stocking 

should be maintained i0 

6. Corrective Pruning- is only higher than suggested fo

necessary when a tree fails to plantation after the fir

develop a straight, central stem commercial thinning to a

and does not maintain a healthy, excessive epicormic sprou

apically dominant terminal leader, and to guard against wind

Causes can be anyone of many, but damage, sun scald, etc.

usually one of these is most likely:

By the time a second pre

a. Late frost kills terminal commercial thinning is n

• bud and lateral buds try stand density should be 

to take over. to the recommended stock

level for a plantation.

• b. Casebearer moth, shoot moth,

or other insects which also 9. Maintenance of firebreaks and

kills the terminal bud. access roads--this usually pe

just to the practices needed 

c. Mechanical damage such as ice, prevent erosion and sedimentat

wind or birds breaking terminal

leader, a. Waterbars on steep slope

• b. "Thankyou Mams" or drain

d. Genetically inferior stock-- c. Box culverts

wants to be a bush rather than d. Improved stream crossings

a tree. Usually corrective e. Seeding, fertilizing, li

pruning won't work and the and mulching bare soil

bad apple has to be removed.

So far, I have deliberately faile

7. Side Limb Pruning-- Can also be mention cost-share rates and hold-down 

• lessened by interplanting-must be because in this discussion they are no

done before diameter of pruned important. What is important is that 

branches reach 2 inches and before is enough incentive to encourage peopl

bole (main stem of tree) reaches have the good walnut growing sites and 

i0 inches in diameter at breast height have the determination to do what it 

(normally side limb pruning is done grow the walnut trees we need now and 

between 3 and i0 inches DBH). future.

i

, |

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J

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i;

U.S. Department of Agriculture, Forest Service.

Black walnut for the future. Gen. Tech. Pep. NC-74.

St. Paul, MN: U.S. Department of Agriculture,

Forest Service, North Central Forest Experiment !

.. Statlon; 1982. 151 p.

Contains 33 papers presented at the third

symposium on the culture of black walnut. Papers

' s,,mmarlzethe current information on walnut timber

. and nut production.

: KEY WORDS: Insects, disease, silviculture, tree .

improvement, genetics

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_ '_ U.S. GOVERNMENT PR I NT !NG OFF ICE : 1982- 566-664/58

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