No.110

1957

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by J. H. Staeckeief

afíi Ç. W. Jonef

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ASi^SCUlTUREHANQSOOKNO. no 195

fORISr SíRVfCE-ücS; eSPARTMENT OF AííPIICUiTyi?
(I-M)

NATIONAL

LIBRARY
474017

Forest Nursery Practice

in the

Lake States

By J. H. Stoeckeler^ forester, Lake States

Forest Experiment Station (maintained

by the U. S. Department of Agriculture in

cooperation with the University of Minnesota), and G. W. Jones, forester, North

Central Region, U. S. Forest Service.

m.

•^"^ ^~'- ' ' . err

FOREST SERVICE, U. S. DEPARTMENT OF AGRICULTURE

For sale by the Superintendent of Documents, U. S. Government Printing Ofl&ce

Washington 25, D. C. - Price $2
ACKNOWLEDGMENT

Forest nursery practices for the Lake States region have

developed through the ingenuity and research of nurserymen

engaged in the production of planting stock. Over the past 25

years many people have made substantial contributions to the

material assembled in this handbook. Forest Service nurserymen furnished willing assistance in the research, and they and

their associates, W. H. Breuer (Wisconsin Conservation Department), E. J. Eliason (New York State Department of Conservation), and Thor Bergh (Soil Conservation Service) made substantial contributions to the nursery techniques.

The helpful assistance of technical reviewers of various

sections of the manuscript is also acknowledged: Soils—S. A.

Wilde (University of Wisconsin); Insects—A. C. Hodson (University of Minnesota) and R. D. Shenefelt (University of

Wisconsin); Diseases—D. W. French (University of Minnesota),

A. J. Riker (University of Wisconsin), and F. C. Strong (Michigan State University). In addition, the authors gratefully

acknowledge the help of Forest Service co-workers who took

part in the investigations and of those who, through consultation and review, aided in preparation of the manuscript.

II
CONTENTS

Page

Introduction 1

Collection and handling of seed 3

Importance of seed source 3

Where and when to collect seed 4

Determination of seed ripeness and quality 5

Collection of seed and control of its origin 5

Handling of cones and fruits immediately after

collection 7

Extraction of conifer seed 7

Cone shaker 10

Dewinging of seed 12

Fanning and cleaning the seed _- 13

Size of seed in relation to germination and size

of seedlings produced 13

Extracting seeds of dry-fruited broadleaf species. 13

Extracting seeds of pulpy-fruited species 14

Yields and costs of seed extraction 14

Seed storage 15

Dry cold storage 15

Dry storage at room temperature 15

Moist cold storage 15

Seed dormancy and pretreatment 15

Seed testing 16

Application of germination tests to nursery seeding 17

How to select a nursery site 19

Climate 19

Topography 19

Soil texture 19

Soil fertility 19

Vegetative cover 20

Water supply 20

Labor supply 21

Trar^sportation and communication 21

Nearby sources of peat and sphagnum moss 21

Size of area as related to production needs 21

Development of the nursery site 23

Subdividing the nursery 23

Windbreak protection 23

Land development 24

Road system 24

Fences 25

Pumping and irrigation plants 25

Pumping from open water supply into an overhead irrigation system 25

Pumping from wells 25

Distributing mains 27

Irrigation, systems 29

Protection against freezing 30

Nursery buildings and other installations 30

Nursery personnel 32

Machinery, tools, and specialized equipment 33

Traction equipment 33

Ground preparation equipment 33

Seeding equipment 34

Fertilizing equipment 35

Transplanting equipment 35

Weeding and cultivating equipment 36

Lifters and root pruners 37

Sprayers 37

Seedbed boards 38

Seedbed screens 40

Handtools ^ 40

Soil management 41

Fertility of nursery soils 41

Fertilizers 44

Malnutrition symptoms 49

Page

Soil management—Continued

Dividends from nursery fertilization 49

The mycorrhiza problem 51

Experimental plots 53

Age classes of stock needed for reforestation 54

Seedbed preparation and sowing 59

Broadcast seeding 60

Drill seeding 61

Density of seeding 61

Computing the amount of seed to sow 63

Depth of seeding 64

Time of sowing 64

Seedbed mulches 65

Soil moisture and irrigation 67

Methods for measuring soil moisture 68

Improving drought resistance by regulated

watering 69

Seedbed care during germination and the seedling

stage 71

Half-shade 71

Thinning --- 72

Watering 72

Cultivation and weed control 72

Top and root pruning as a substitute for transplanting 75

Transplanting operations 79

Lifting stock for transplanting 79

Preparation of the transplant bed 80

Methods 81

Spacing 81

Hand transplanting 82

Machine transplanting 83

Care of the transplant bed 84

Hardening-off 85

Special propagation methods 86

Dormant stem cuttings 86

Root cuttings 86

Grafts 86

Nursery protection 87

Unfavorable weather conditions- 87

Mammals and birds 87

Nursery diseases 88

Damping-off 88

Cedar blight 89

Leaf diseases 90

White pine blister rust 91

Rusts of hard pines 91

Sweetfern blister rust of pitch pines 92

Snow mold 92

Molds or rots in storage or transit 92

Rots of seed in beds 92

Root rots 92

Cedar-apple rust ^ 93

Needle cast 93

Cytospora canker of poplar and willow 93

Nursery insects 93

White grubs 94

Ants 94

Strawberry root weevil 94

Wireworms 95

Grasshoppers 95

Bark aphids 95

Spruce gall aphids 95

Cutworms 95

Red spiders 96

Scale insects 96

Tip-boring insects 96

III
Page

Nursery protection—Continued

Nursery insects—Continued

Sawflies 96

Pales weevil- 97

Blister beetle 97

Cottonwood and willow leaf beetles 97

Red-humped caterpillar 97

Nut weevils 97

Nematodes 97

Mechanical injury 97

Chlorosis 97

Inventory 98

Lifting, grading, and packing of nursery stock 101

Digging 101

Pulling 101

Grading 102

Pruning 103

Packing 104

Shipping weight of trees 107

Storage and shipment of nursery stock 108

Page

Cost of tree production 111

Literature cited 112

Appendix 118

Common and scientific names of trees and shrubs

mentioned 118

Safety rules and precautions for handling, mixing,

and applying chemicals 118

Spray formulas for insecticides and fungicides 120

Mouse baits 120

Conversion factors 120

Sources of information on nursery problems 123

Sources of information on nursery machinery,

equipment, and chemicals 123

Requirements and procedures for nursery stock

inspection in the Lake States 123

Where to purchase seed 123

Where to purchase nursery stock 124

U. S. Department of Agriculture forest seed policy

(1939) 124

IV
INTRODUCTION

In 1950, Michigan, Wisconsin, and Minnesota

had an estimated 12.5 miUion acres of forest land

in need of planting (131)} A 1952 estimate,

based on a different set of criteria for plantable

area, was 8.5 million acres {180a). The latter,

more conservative estimate accounts for about

one-sixth of all the commercial forest land in the

Lakes States region. Only 10 percent of the

original pine, spruce, and fir^ forests have sur1 Italic numbers in parentheses refer to Literature Cited,

p. 112.

2 A list of common and scientific names of trees and

shrubs mentioned in this pubUcation appears in the

Appendix, p. 118.

vived logging and fire. The remainder of the

forest land is denuded or understocked, or has

converted to lower value species.

Because the region is not self-sustaining in wood

production and demands for wood products are

increasing, these understocked and denuded areas

should be restored to high productivity by tree

planting. In addition, decades of fire protection

and encouragement of natural reseeding by scientifically managed cutting of the remaining forest

will be required.

A rebuilding program is already under way and

gaining more support every year. One large

TABLE 1.—Forest tree nurseries in the Lake States operated by local public agencies, the Federal Government,

and forest industries to grow stock for reforestation and shelterbelts, 1952

State and nursery Location

Michigan:

Bogue

Chittenden

Dunbar

Hardwood State

Higgins Lake State

North Muskegon Soil Conserv. Dist_

South Muskegon Soil Conserv. Dist_

West Ottawa Soil Conserv. Dist

Russ

J. W. Tourney

Wyman

Total (11 nurseries)-

Minnesota:

Badoura

Eveleth

General Andrews _

Knife River

Lydick

Winona__

East Lansing

Wellston

Sault Ste. Marie_

Boyne Falls

Roscommon

Dalton

Fruitport

West Olive

Decatur

Watersmeet

Manistique

Ownership

class 1

Operator

S

F

S'

S

S

c

c

c

s

F

S

Total (6 nurseries).

Wisconsin:

Butternut

Clark County Transplant

Gordon State

Griffith State

Hayward State

Hugo Sauer

Marathon County Transplant.

Monico

Nepco Lake Port Edwards___-

Trout Lake Boulder Junction.

Akeley

Eveleth

Willow River _

Two HarborsCass Lake

Winona

Butternut

Neilsville

Gordon

Wisconsin Rapids _

Hayward

Rhinelander

Wausau

Monico

S

F

S

I

F

F 4

Mich. State University _

Forest Service

Mich. State University _

Mich. Dept. Conserv

do

Soil Conserv. Dist

do

doMich. State UniversityForest Service

Mich. Dept. Conserv

DeptTotal (10 nurseries)

Grand total (27 nurseries)-

F

S

S

S

s

F

S

I

I

s

Minn. Conserv.

Forest ServiceMinn. Conserv. DeptNo. Star Timber Co..

Forest Service

Soil Conserv. Serv

Trees

produced

Thousands

2, 361

4, 831

1, 660

1, 580

14, 869

500

550

1,496

849

2, 644

256

31, 596

Forest Service

Wis. Conserv. Dept.

.--_do

do

do

do

doConsohdated Water Power

& Paper Co.

Nekoosa-Edwards Paper Co.

Wis. Conserv. Dept

3,598

1, 925

3, 598

20

3, 904

13, 025

247

3,389

8, 889

3,604

2,338

110

292

1, 500

2, 634

23, 003

67, 624

iF= Federal, S = State, C = Commercial, I = Industry.

2 Recently reactivated.

3 TT^fictive

4 In 1954 this nursery was transferred to the Game Division of the Minnesota Conservation Department.

Forest Nursery Practice in the Lake States
phase of the program is the reforestation of cutover and burned-over lands. Participants include

Federal, State, county, township, and city governments, and pulp and paper mills, lumbermen, and

farmers. The trees are supplied largely by 27

nurseries located within the region and operated

by local public agencies, the Federal Government,

and forest industries (table 1). The combined

production of these nurseries in 1952 was 67.6

million trees.

As an example of the rebuilding program, some

69 thousand acres of forests and shelterbelts were

planted between July 1, 1951, and June 30, 1952.

This planting was on land in all classes of ownership, with 29 percent of it in Wisconsin, 18 percent

in Minnesota, and 53 percent in Michigan. Together, the 3 States planted 13 percent of the

national total for that year. To 1952, they had

planted about 22 percent of the national total.

The large-scale program of tree planting in this

region, which began in the 1930's, has furnished a

rich background of experience in production of

nursery stock. This pubhcation presents the

results of that experience and supplements it with

observations from a large number of nursery experiments and field-planting tests. Emphasis is on

mass production of 1- to 4-year-old nursery stock

grown from seed and suitable for reforestation.

Agriculture Handhook 110, U. S. Department of Agriculture
COLLECTION AND HANDLING OF SEED

IMPORTANCE OF SEED SOURCE

''Seed source^' refers to the geographic locaHty

and type of trees from which seed is collected. It

is desirable to use seed from well-formed, vigorous

trees of local origin wherever possible, because

trees grown from seed of distant areas often suffer

more damage from freezing, drought, insects,

disease, or physiological disturbances. Moreover,

such trees are sometimes crooked, limby, stunted,

or rapid in taper, and these defects may not show

up for 20 years or more after planting. If seed

from distant sources are used, tests should first

establish the superiority of the race.

European countries have a much broader experience than the United States on the harmful effects

of the use of seed without regard to its origin.

Some of them have passed strict laws providing

for certification of the source of seed. Germany,

particularly, developed a rigid seed certification

program which became a law in 1934 (8),

One of the early advocates of a better seed program in the Lake States was C. G. Bates (6) who

suggested certification of seed that was collected

from disease-free trees of desirable form. He also

proposed setting aside "tree seed farms" consisting

of the best natural or planted stands in various

locations and using them as seed collection areas (7).

As a supplement, he suggested standwise progeny

tests to verify the value of various geographical

strains (8).

In reviewing the experiences of European

countries, Baldwin and Shirley (S) outlined a

forest seed program for the United States. It was

based on the use of local seed of known origin and,

in case of dependence on distant sources, on

intelligent selection based on a knowledge of mean

temperature of the growing season (usually June

to September) along with a knowledge of length of

growing season.

Bates (9), in a study of frost hardiness of geographic sources of red pine, found in controlled

laboratory tests that the northern sources were

much superior to those of southern origin.

In general, species native to the Lake States

have shown much better results than exotics as

regards survival, form, and resistance to winter

injury (162). In the Lake States, as well as in the

Northeast, Scotch pine has proved to be a particularly poor species in spite of good initial growth.

Not only has it generally been surpassed in growth

by red pine, but it has tended to be heavy limbed

and often crooked boled, by comparison. It is

also more subject to attack by insects, such as the

root collar weevil, and to attack by porcupines.

Forest Nursery Practice in the Lake States

The general failure of Scotch pine in the Lake

States is attributed in large part to poor seed

source.

A great deal of work in Sweden has led to the

recommendation that the mean summer temperature of the planting site should not vary more than

about 1° C. (1.8^ F.) from that of the home of the

parent seed trees (84) • Wakeley (183) found that loblolly pine trees

from seed collected from within 50 miles of the

planting site produced 1.9 to 2.7 times as much

merchantable pulpwood as did stock grown from

seed originating 350 to 450 miles away.

On May 16, 1939, the U. S. Department of

Agriculture adopted a uniform seed policy approved by the Forest Service and the Soil Conservation Service (appendix, p. 124). It requires

these agencies to use, wherever possible, seed of

known origin from areas of similar climatic influences. This usually means collected within 100

miles and within 1,000 feet elevation of the planting

site. It further recommends keeping a record on

such seed: lot number, year of seed crop, species,

origin as to State and county locality, range of

elevation, and proof of origin.

For the more important reforestation species,

such as red, white, and jack pines, and white and

black spruces, the above policy can be followed

in the Lake States region without too much difficulty. ^^Tree seed farms'^ should be designated in

local stands of well-formed native species and

efforts made to collect seed from such areas. The

price of seed is a minor item in the ultimate cost

of a forest plantation or windbreak planting, and

it is penny-wise and pound-foolish not to take

advantage of the best seed sources.

An alternative to importing seed from other

countries would be to collect seed of nonnative

species, such as Norway spruce, European larch,

and Scotch pine, from older plantings (preferably

over 40 years of age) in the Lake States. There

are a few such plantations and windbreaks in the

region in which the trees have good form, satisfactory growth rate (50 to 80 feet high), and have

shown some natural reseeding in their new habitat.

These plantings ought to be earmarked as ^'tree

seed farms.''

In summation, a sound seed-collection policy

for the Lake States region should include the

following points:

1. Each State should be zoned into at least 3 or

4 homogeneous seed-collection zones.

2. The progeny obtained from seed collected

from a zone should be planted in that zone wherever possible.
3. The seed should be from trees and stands of

reasonably good growth rate and form, with

straight, clear stems free from internal defect and

with branches of small diameter in relation to bole.

4. Seed imported from European or Asiatic

countries should not be used to any extent in the

reforestation program. If used at all, it should

come from localities climatically similar to the

Lake States area where the trees are to be planted,

and the program should be limited to those few

species that have shown good growth and adaptability in provenience (seed-source) tests. A few

older plantations of exotics now growing in the

Lake States could qualify.

5. A tree seed certification program should be

developed with particular emphasis on a guarantee

of the origin of the seed.

WHERE AND WHEN TO COLLECT

SEED

Tree seed collection should be confined to areas

where the trees are of good form and vigor, because trees of poor form may transmit this undesirable character to the progeny. There are good

collection areas on national and State forests, and

on industrial forests and other private lands.

Windbreaks and shelterbelts offer another possible source for seed. Landowners seldom object to

the gathering of cones from standing trees or

squirrel caches by seed collectors even though the

cones collected will be sold to others. However,

the seed picker should first get permission from

the landowner.

Many species of trees produce a bumper crop

of seed only once in 4 or 5 years, and a fairly

good crop only every second or third year (180).

Therefore it is to the advantage of the collector

to concentrate seed picking in those years when

cones or fruits are plentiful and well filled. The

seed thus obtained will generally be of high viability and much cheaper per pound than lots collected in lean years. It can be stored for 4 or 5

years without losing much of its viability if proper

conditions of moisture and temperature are maintained.

The abundance of seed crops during an 8-year

period (1946-53) in Wisconsin varied widely (table

2). Red pine and tamarack had good or bumper

crops in only 1 out of 8 years, and white spruce

in only 2 out of 8 years. Lack of seed of the pine

and spruce is likely to be a bottleneck in nursery

production if a fairly good carryover of seed is not

provided. It was noted that a good or burnper

crop was rather frequently followed by a failure

or by a poor crop but that in no case were there

two complete crop failures in a row.

For tree-seed production generally, the 8 years

for Wisconsin can be rated as follows: 1946, poor;

some species fair. 1947, good; some species fair;

a few bumper. 1948, fair; quite a few species

good. 1949, a failure. 1950, bumper; quite a few

species good. 1951, fair; some species poor. 1952,

fair; some species good. 1953, fair; some species

good.

Species in the same genera, for example the

birches, often act alike as regards abundance of

seed produced. This is especially true for species

whose seed ripen at about the same time of year.

TABLE 2.—Frequency of seed crops in Wisconsin,

1946-53

Years with seed crops rated 1o

as ^— bß o

Species a <D

.1í 4^

ft

S o

ê

2

1

1

Num- Num- Num- Num- Num- PerConifers: ber ber ber ber ber cent

Fir, balsam 2 3 0 1 2 62

Hemlock 2

0

2

3

2

4

2

0

0

1

50

Pine, jack 37

Pine, red 0 1 2 4 1 12

Pine, white 1 2 2 3 0 37

Spruce, black ^ 1 2 2 2 1 37

Spruce, white 1 1 3 1 2 25

Tamarack 1 0 3 2 2 12

White-cedar 2 2 2 1 1 50

Broadleaves:

Ash, black 1 2 2 1 2 37

Ash, white 1 3 1 1 2 50

Basswood 2 3 1 1 1 62

Birch, paper 1 3 1 1 2 50

Birch, yellow 2 2 2 1 1 50

Cherry, black 2___ 2 1 2 1 1 4;^

Elm, American 3__ 0 3 2 0 1 50

Hickory, shagbark^ 2 1 2 1 0 50

Maple, sugar 0 4 1 2 1 50

Oak, red _ 1

0

2

3

3

3

1

1

1

0

37

Oak, white 2 43

Walnut, black 4___ 0 3 2 0 Ü 60

1 Abundance is described as follows in terms of percentage of full crop: bumper, 91-100; good, 61-90; medium,

36-60; poor, 16-35; failure, 0-15.

2 Basis: 7-year record.

3 Basis: 6-year record.

4 Basis: 5-year record.

Seed crops in the Lake States are Hkely to be

less abundant on trees growing near the edge of

the natural range of the species. For instance,

good or bumper seed crops of northern red oak

were observed only 1 year out of 6 in northern

Wisconsin near the northern limit of its geographic

range, whereas in southern Wisconsin good or

bumper crops were observed in 2 out of 6 years.

Most pines require 2 years to mature cones;

hence, in late summer or fall the cone crop for the

year following can be predicted to some extent

from the number of immature first-year cones.

Weeviling or adverse weather, such as severe

drought, in the following year can, of course, upset

such estimates.

Agriculture Handhooh 110^ U. S, Department of Agriculture
DETERMINATION OF SEED

RIPENESS AND QUALITY

Seeds of most tree species ripen and are ready

for picking in the late summer or fall, but there

are exceptions. For instance, American elm and

aspen seeds ripen in May; those of red maple and

rock elm in June. Some conifers, notably white

spruce, open their cones and disperse seed the last

week of August. Such cones must be harvested

during a very short period, often no longer than

10 days in contrast to the 20 to 30 or more days

for most other conifers.

Ripeness of cones of some species can be judged

by a change in the color as from green to deep

purple or brown. For instance, red pine cones

are ripe when they turn purplish with brown on

the scale tips, and white pine cones turn yellowish

green with brown on the scale tips. Jack pine can

be collected when half or more of the cone surface

is brown. Change of color in balsam fir cones

(purpling) and in juniper berries (blue) is indicative of ripeness.

The specific gravity of freshly picked cones is

also an indication of ripeness, particularly for some

pines (130). A simple method for determining the

specific gravity of red and white pine cones is to

use separate containers with water, linseed oil,

equal parts of linseed oil and kerosene, and kerosene. If five or more freshly picked cones sink in

water, the crop is still too green for collection. If

the white pine cones float in linseed oil (specific

gravity about 0.93), they are ripe enough for collection. Red pine is not fully ripe until the cones

float in the solution of lowest specific gravity, i. e.,

kerosene, having a specific gravity of about 0.80.

However, red pine cones floating in the 50-50 mixture of linseed oil and kerosene are within 10 days

of being fully ripe.

Seeds of broadleaf species are judged to be ripe

when they have lost their watery or milky character, they are firm and fully developed, and their

color has changed from green to tan or grayish.

However, fully ripened seeds of some broadleaf

species can only be obtained with certainty by

waiting until seed dispersal begins. This applies

particularly to oaks and poplars.

Seed quality can be determined by cutting tests

made in the field. Areas producing a high percentage of hollow or weeviled seed should be

avoided.

COLLECTION OF SEED AND

CONTROL OF ITS ORIGIN

It may be more feasible for commercial nurseries

to purchase seed than to engage in collecting. Seed

can be obtained from collectors or seed dealers or

by the open-market purchase of cones. If a reliable collector or seed dealer will guarantee collection area and year of collection, seed of good

quality from stands reasonably good to excellent

in form may be obtained.

Tighter control of seed origin can be had by

hiring seed pickers to collect ripe cones or seed

from a specific timber sale area as the timber is

felled. A further refinement is to have a collectingcrew foreman designate individual trees from which

the cones or seed will be picked. Another control

method is to have an agreement with the operator

on the sale area for felling the very best seed-bearing trees at the proper time of seed ripeness prior

to the late fall or winter cutting. This procedure

is applicable to red pine, white pine, balsam fir,

and other species whose cones open or whose seed

is dispersed naturally in late September or October,

but it is of especial value for white spruce whose

cone-harvesting span is often only a 1-week period

in late August.

Cones can also be collected from squirrel caches

or from the ground as squirrels cut them. Pine

cones collected from squirrel caches or cuttings

will probably be of fairly good genetic character

if the stand as a whole is composed of trees of

good form.

Cones or fruits of some species, notably elm,

ash, and low white-cedar or junipers, can be

shaken, flailed, or stripped onto canvas or cloth.

Elm seed is occasionally swept up from streets,

sidewalks, or other hard surfaces.

Collecting from standing trees is the most diflicult. Seed pickers are usually equipped with

climbing irons or ladders, depending on height

and limbiness of the trees. The cones or seeds

are stripped off by hand and dropped into a sack

or picking bag. For species like ash, a light finetoothed rake can be used to dislodge the seed;

the seed can then be caught in a net held by the

picker or allowed to fall onto tarps or burlap.

Juniper berries and white-cedar cones can be

stripped from lower branches onto canvas by

gloved hands or with a fine-toothed rake.

Considerably more cones or seed per day can be

harvested from felled, individual trees if a large

square of burlap, old canvas, or cheesecloth is

placed where the seed-bearing top will strike.

This procedure is of value chiefly where large

amounts of seed will become detached when the

tree strikes the ground. Cutting out the heavily

laden tops of spruce or balsam fir trees at the time

of seed ripeness and dropping or lowering them to

the ground is another method of collection. The

trees are felled in the logging operation later.

The volume or weight of cones or seed that can

be collected in an 8-hour day by a picker varies

greatly according to species, character of the

s-tand and individual trees, abundance of seed,

method of collection, organization, and equipment. For instance, a picker can collect only a

bushel of cones per day from standing red pine

trees, but from felled trees, he may obtain 2 to 3

bushels. Some collectors have obtained as many

as 6 to 8 bushels in a day from squirrel caches.

Forest Nursery Practioe in the Lake States
Small cones, such as jack pine, tamarack or

white-cedar and others, are rather slow to collect.

From felled trees, when the crop is good, 1 man in

1 day can gather 2 bushels of spruce or balsam fir

cones, 1 bushel of red oak acorns, or about K to %

bushel of white oak acorns. One man in one day

can easily collect ji bushel of fruits of such species

as sugar maple, basswood, ash, and birch. Collins

(34) reported in an Ozark study that from 0.2 to

1.9 bushels of acorns were picked per man-day,

with best production obtained from recently felled

trees.

Oak seed can also be picked efficiently from the

ground after natural seed fall. The acorns that

fall earliest are often wormy, hollow, and of poor

quality. They should be avoided if possible.

To remove hollow or wormy acorns, the collection

should be dumped into a tub of water and the

floaters skimmed off and discarded. The remaining acorns and K to 1 cup of carbon disulfide

should be placed in a metal container, such as a

seed or milk can, and sealed up for about 48 hours

to kill the seed-eating larvae often found in acorns.

Miller (96) in time studies on cone collection in

Chippewa National Forest, Minn., found that

production per man-day was as follows when

handpicking from ladders: Jack pine, red pine,

and white spruce, 1^ to 2 bushels; white pine, 3

to 4 bushels. This agrees rather well with a study

made in Ontario by Richardson (118) who reported that 2.15 bushels of red pine were collected

per man-day of 9 hours when cones were picked

from the tree with hooks and bags. Miller

reported that when cones were obtained from

squirrel caches, the men were able to get from 5

to 6 bushels of white pine and up to a maximum of

8 bushels of red pine. Individual squirrel caches

may contain up to IK bushels of cones of red pine.

Recommended practice is to leave part of the

cache for the squirrels.

Cones found in squirrel caches generally are of

good size and contain well-filled seed. Squirrels

do, however, cut cones slightly before full maturity. Barton,^ in comparing red pine cones freshly

cut by squirrels with those handpicked at the

same time, noted that germination increased

somewhat between early September collections

and those made 2 to 3 weeks later:

Date collected Method of collection

Sept. 3 Squirrel-cut

3 Handpicked

17 Squirrel-cut

17 Handpicked

24 Squirrel-cut

24 Handpicked

Percent ofseed

germination

88

87

97

96

100

100

Other observations indicated that squirrels began

cutting red pine cones 10 to 14 days before the

seed had attained high germinability, but that

they did not begin to cut white pine cones until

the seed were highly germinable (ISO),

3 Hugo Sauer Nursery, Rhinelander,

lished annual report. 1938.

Wis. UnpubPicking from trees felled in logging operations

during a period when the seed is fully matured

will reduce seed collection costs. This practice

has the further advantage of allowing one to pick

from some very select, tall trees that would be

extremely difficult or risky to climb. Bryan (20)

reported that Civilian Conservation Corps men

were able to pick an average of 3 bushels of shortleaf pine cones per man-day from felled trees but

only %, bushel per man-day from standing trees.

Studies of red pine cone size in relation to seed

yield made at Rhinelander, Wis., in 1938 revealed

that medium- and large-sized cones had between

2.1 and 2.2 times as many viable seeds per bushel

as small cones, although the total weight of seed

per unit volume of each class of cones was about

the same. Small cones were defined as those with

a volume of 8 to 13 cubic centimeters per freshly

collected cone, medium cones ranged from 13 to

17, and large cones from 17 to 22. Average

volumes were 9.5, 15.0, and 18.1 cubic centimeters,

respectively, and average total number of seed per

cone was 19.6, 34.1, and 43.1, respectively.

The number of red pine seedlings produced per

cone also increased with cone volume, as follows:

ïrïlhlonei Seedlings pro-

(cvbT duced per cone I^CUOIC (rn'„mh/>r\

5 0

6 0

7 0

8 0. 7

9 1.5

10 2.2

11 3.0

12 3.6

mlhlLi Seedling, pro.

laS duced per cone

13 4.4

14 5. 0

15 5.7

16 6.3

17 7.2

18 7.9

19 8.6

20 9.3

Cones with a volume less than about 8 cubic

centimeters contained practically no viable seed,

whereas cones 15 to 20 cubic centimeters in volume

gave especially good yields. The amount of viable

seed was not as high as expected because of early

collection, but the general conclusion was that

small, runty cones should neither be collected nor

purchased.

Eliason and Heit (45) found similar results in

Scotch pine and concluded that cones less than 1.5

inches long produced smaller seed and also smaller

seedlings than three larger grades of cones ranging

from 1.5 to 2.25 inches in length.

Normally, cones are purchased by the bushel,

but there may be great variation in the number

of cones per unit of volume. As a general rule,

in the Lake States cones can be measured satisfactorily by volume if they are completely unopened at the time of delivery.

Cottonwood or aspen seeds are collected by

picking the clusters of cottony material just as the

first ones are beginning to open and drift away in

the wind. The clusters need drying for several

days on screens. They should then be rubbed

gently to separate the seed, and the seed immediately sown (19).

Agriculture Handbook 110,, Ü, S, Department of Agriculture
More details on methods of collecting various

species of tree seed are given in table 3. The

table is based on experience in a number of

nurseries in the Lake States and on seed tests in

sand flats at those nurseries as well as at other

testing laboratories (ÍSO). -

HANDLING OF CONES AND FRUITS

IMMEDIATELY AFTER COLLECTION

Practically all cones, berries, strobiles, or other

fruits must be spread out in layers on hardwarecloth trays in a cone shed or on a floor in a barn

or shed to obtain enough superficial drying to

prevent molding or heating. The layers should

not be more than 2 to 4 inches thick for cones, or

1 to 2 inches for the seed of the broadleaf species.

They should be protected from rain. This predrying will require some 3 to 10 days, depending

on drying conditions.

Predrying is especially necessary for maple,

birch, ash, and elm because they mold and heat

readily if left in collection sacks. Fruits should

be turned over daily to expedite drying, and it is

advisable to turn the soft, relatively moist fruits

of broadleaf species twice a day during the first few

days. At the Cass Lake Extractory of the United

States Forest Service, red pine cones are predried

from the time of collection until midwinter to

obtain the highest seed yield in extraction.

In most State or Federal nurseries of the Lake

States, cone storage sheds are designed with ventilators at the top to give a maximum of air circulation

(fig. 1).^ Along the sides, upward-swinging, horizontally hinged doors can be lifted to expose openings screened over with }^-inch hardware clotli.

The cones are placed in trays which vary in size

• Detailed plans for cone shed are available from the

Regional Forester, U. S. Forest Service, Milwaukee 3,

Wis,

from 4 by 4 feet to 4 by 12 feet. The trays,

usually 4 inches deep, have hardware-cloth bottoms. A tray 4 by 8 feet will hold about 4 bushels

of cones. Often 15 or more trays are stacked in a

tier, at the bottom of which is placed fine screen

to catch seeds which drop out of the cones.

Pine cones can conveniently be left in the trays

for 2 months of predrying and then dumped in

stockpiles in a corner of the warehouse or cone

shed untü ready for extraction in the kiln. Each

lot of a specific origin should be kept separate in

storage and extraction to comply with the United

States Department of Agriculture Seed Policy or

with such rules as are in line with an agency's

policies. The Forest Service in the Lake States

area keeps seed lots separate by national forests

and year collected.

EXTRACTION OF CONIFER SEED

In the Lake States most conifer seed is extracted

from cones in artificially heated, specially constructed kilns (fig. 2). Artificial heat usually

gives more complete extraction of the seed than

air-drying or solar heat. Balsam fir, however,

does not require kiln treatment. When cones of

this species are air-dried in a cone shed, the scales

break away from the central axis of the cone and

the mixture of seed and scales is then separated

by dewinging and cleaning in a fanning mill.

The temperature, humidity, and duration of

kiln treatment vary for different species (table 4).

The temperatures used in the forced-air kiln at

the Hugo Sauer Nursery (table 4) are slightly

lower than those given by Rietz {119). He recommends 140° F. for 12 hours at 17 percent

relative humidity for air-dried cones of eastern

white pine; 170° for 7 hours at 20 percent

humidity for jack pine; and 160° for 9 hours at

17 percent relative humidity for air-dry or fresh

cones of red pine.

M-29423-F

FIGURE 1.—This cone storage shed is 30 bv 70 feet

and will hold 2,300 bushels

of red pine cones on

trays. (Chittenden Nursery, Wellston, Mich.)

Forest Nursery Practice in the Lake States
TABLE 3.—Summary table for seed collection, extraction, treatment, and nursery seeding

Data on fruits and cones

Type and shape Length

Time of collection

Collection

method 1

Extraction

method 2

Number Number

2 or 4 1

2 72

2 1

2 1

2 1

2 1

2 or 5 2or 1

2 or 5 1

2 1

2 or 5 1

3 or 2 5

2 1

2 1

2 1

2 1

2 1

2 or 3 2orl

2 or 3 3 or 4

2 or 3 3 or 4

2 or 3 3 or 4

2 8

2 3

1 3

2 3

2 3

3 or 2 5

Weight

per

rough

bushel of

fruit as

picked

Clean

seed per

rough

bushel of

fruits 3

Seeds per

pound *

Cutting

test

Germination

in

laboratory

sand

flats

Number Percent Percent

40, 300 92 85

57,600 51 22

187, 000 80 38

73,900 55 40

26,000 88 70

123,000 94 68

14,840 75 54

55,000 96 85

66,000 96 44

27,000 92 64

41,000 60 35

390,000 80 50

60,000 85 70

180, 000 85 50

216,000 80 50

278,800 60 47

300,000 52 50

8 8,670 95 20

8 16,000 85 42

8 10, 200 92 50

3, 600,000 90

3,550 73 25

1,385 90 86

8 918,000 35

8 371,000 29

5,000 94 63

Approximate

ratio 1-0

nursery

stand to

laboratory

germination ^

Depth

of

seeding

Inch

0.40 %

.60 3/8

.40 %

.40 3/8

.60 Vt

.50 H

.70 1/2

.65 3/8

.70 %

.65 Vl

.60 3/8-1/2

.40 H

.35 H

.40 H

.35 1/4

.50 M

.10 /8

.75 3/

.70 /2

.70 1/2

.01 0

.30 %

.75 %

.15 1/4

.12 M

.50 1/2

Type of seed

dormancy

Season of sowing and

seed pretreatment if

spring sown 6

Conifers:

Douglas-fir,

Fir, balsam

Hemlock, eastern.

Larch, European,

Pine, Austrian

Pine, jack

Pine, ponderosa...

Pine, red

Pine, Scotch

Pine, white

Cone

Upright purplish cone_

Cone

_do-.

-do.

-do.

-do-

_do.

-do-

-doCi)

Redcedar, eastern. Blue berrylike concSpruce, black

Spruce, Norway

Spruce, western white _

Spruce, white

Cone...

--do-

-do-

-do.

Tamarack

White-cedar, northern

Broadleaves:

Ash, black

_^-do...

ConeletAsh, green.

Paddle-shaped samara.

do

Ash, white

Aspen, quaking-.

Basswood

-do.

Beech, American.

Birch, paper

Birch, yellow-.

Cherry, black.

Silky-winged seed borne

in long, pendulous

catkins.

Several grayish-brown,

round nutlets attached

to curved wing.

A 2-celled burr

Strobiles contain tiny,

flat, disklike samaras.

-.-do

Black, 1-seeded drupe...

Inches

3.0

1. 7-2. 7

.4

. 7-1. 2

2. 0-4. 0

1. 5-2.0

3.0

1. 5-2. 5

1. 2-2.0

5.0-7.0

.1- .2

.6- .9

4. 0-6. 5

1.0-2. 0

1.0-2. ë

.5- .7

.25

1.0-1. 5

1. 2-1. 5

1.2-1. 5

2. 5-3. 5

.25

.5- .7

1. 2-1. 7

. 9-1.2

. 2-. 25

Late Aug.-SeptSept

do

do

Sept.-Oct

Sept.-Nov

Sept

do

Late Sept.-NoVSept

Oct.-Nov

Oct

Sept

Late Aug.-early

Sept.

do

Sept

Late Sept-Oct __

Oct.-Nov

Sept.-Oct

do

Apr.-May

Sept.-Nov

Sept.-Oct

do..:

do

Aug.-Sept

Pounds

35

25

45

20

45

40

44

35

32

32

35

39

35

25

8 12

8 12

8 12

9 15

10

25

Í 13/.

89

55

Pounds

0.70

2.10

1.95

.93

.60

.52

1.25

.46

.50

.95

5.20

.25

.65

.40

.75

1.05

8 9.00

8 8.00

8 8.00

5.90

9.00

8 2.10

8 2.70

11.00

Embryo

do ...

do

Embryo, slight

None

do

do

do

do

Embryo

Embryo and

seedcoat.

Embryo, slight

do

None

Embryo

Embryo, slight

do

Embryo and

seedcoat.

Embryo

do

None

Embryo and

seedcoat.

Embryo

Embryo, slight

do

Embryo

Fall-sow or stratify 60

days.

Fall-sow or stratify 90

days.

Fall-sow or stratify 60

days.

Do.

Spring or fall.

Do.

Do.

Do.

Do.

Fall-sow or stratify 60

days.

Fall-sow or stratify 90

days.

Fall or spring.

Do.

Spring or fall.

Fall-sow or stratify 60

days.

Fall or spring.

Fall-sow or stratify 30

days.

Stratify in April, seed in

fall.

Fall-sow or in spring

soak in cold water 10

days, changing daily.

Fall-sow or stratify 60 to

90 days.

Sow as soon as collected.

Fall-sow; mulch for IJ^

years.

Fall-sow or stratify overwinter.

Fall-sow or stratify 30

days.

Do.

Fall-sow or stratify 120

days.
o

Oc

Ci

Cottonwood, eastern.

Elm, American

Elm, rock

Locust, black.

Maple, red...

Maple, silver..

Maple, sugar

Oak, northern redOak, white

Walnut, black.

Silky-winged seed borne

in pendulous catkins.

Flat, elliptical, winged

fruit.

do

Brown, elongated pod--

Winged samaras in pairs

...do.

Acorn „

_do_

Nut contained in darkbrown, oily husk.

2.5-4.0

.3- .4

.5- .6

3.0-4.0

.6- .8

1. 2-2. 2

. 8-1. 2

.7- .9

.7- .8

2. 5-3.0

Apr.-May

May

June

Sept.-OctMay-June

do-—.

Sept.-Oct.

do...._

do—._

Oct

2 8

3 or 6 3

2 3

3 4

2 or 6 3

2 or 6 3

2 or 6 3

1 7

1 7

1 6

15

841/2 8 3.50

8 6.00

2.50

8 9.00

6 10.00

8 12.00

45.00

58.00

10.00

350,000 95 88

8 68,000 96 74

8 6, 690 97 70

22,850 84 67

8 18, 500 87 46

8 1,400 97 76

8 6, 309 52 40

105 85 68

160 85 65

40 99 70

10 0

15 H

35 H

40 %

40 1/2

40 J/2

40 1/2

95 1

95 1

90 1

None

do

do

Seedcoat

Embryo

None

Embryo

....do

None

Embryo and

seedcoat.

Sow as soon as collected.

Do.

Do.

Spring. Scarify; 20-40

minutes sulfuric acid;

or hot-water immersion.

Fall-sow or stratify 40

days.

Sow as soon as collected.

Fall-sow.

Fall-sow or stratify overwinter.

Fall-sow.

Fall-sow or stratify overwinter.

1 Collection method:

1. Pick from ground after natural fall. If necessary, shake trees or jar limbs to remove the fruit.

2. Hand-pick from trees, or from tops after felling.

3. Flail, strip, or shake onto canvas, burlap, or cheesecloth.

4. Pick from ground after squirrel cutting.

5. Remove from squirrel caches.

6. Sweep up or rake up after natural fall on streets.

2 Extraction method:

1. Open cones with artificial heat. Tumble in cone shaker. Fan or screen to separate from cone

Fan seed to remove

2. Open by air-drying on screens. Tumble in cone shaker.

3. Screen through hardware cloth. Pick debris from screen if necessary,

impurities.

4. Run dry through macerator. Fan to remove impurities.

5. Run wet through macerator with water. Float off or screen out pulp.

6. Run through corn sheller to remove husks.

7. Float in water to remove hollow seed.

8. Pick catkins; dry on screens until open and remove capsules and stems.

3 Refers to seed with pulp, pod, or wings removed except where indicated.

^ Rough cleaned to usual standard as seed comes from extractory.

5 Assuming overhead irrigation.

6 See text for supplemental details.

7 Balsam fir does not require cone shaking treatment.

8 With wings left on seed.

^Estimated.

^
Some cones offer great resistance to complete

opening because of ^^case-hardening^' that results

from improper storage of cones or other causes.

Red pine and Scotch pine cones especially tend to

case-harden. To overcome this, the cones are

either sprayed with water or submerged in water

for 12 to 24 hours at room temperature, or they are

soaked for 5 to 20 minutes in water heated to

130° F. After such treatment they are dried

superficially for a day or two and then put into

the dry kün. Some extractories introduce live

steam into the kiln for 30 minutes to aid in opening case-hardened cones.

TABLE 4.—Drying schedule for farced hot-air kiln,

Hugo Sauer Nursery, Wis.

TABLE 5.—Drying schedule for internal-fan type of

seed extractories

Species

Fahrenheit

temperature

Relative

humidity

Time

in

kiln

Amount

of cones

per

tray 1

White pine

Red pine_-

Jack pine

White spruce

Black spruce

Norway spruce

Tamarack

Hemlock

Degrees

120

130

150

130

150

130

150

150

Percent

37

15

27

37

37

37

37

37

Hours

12

9

6

10

20

18

24

12

Bushels

V*

VA

1 Size of trays, 44>^ by 23}^ by 3 inches.

Internal-fan type extractories have a considerably faster schedule of extraction (table 5) than

do other kilns. They handle charges ranging

from 11 to 44 bushels per kiln, depending on tray

loading and spacing. At }{ bushel per tray, the

number of bushels is 16.5 at 2-inch spacing; 13.5

at 2.5 inches; and 11.0 at 3 inches. Tray loadings

may be %, %, ji, or Yzs of a bushel. The usual

tray spacing for most Lake States species is 2 or 3

inches with tray loadings of % to )^ bushel, or an

average of about 22 bushels per single kiln charge.

It is desirable to do as complete a job of extraction as possible, because of the financial loss when

seed are left in the cones. For example, in 1935

an especially recalcitrant batch of red pine cones

was encountered at the Hugo Sauer Nursery.

These cones, on which rather poor extraction was

obtained in the first run, were then soaked in vats

of water for 12 to 24 hours, spread in the sun for

24 to 48 hours, and again run through the kiln.

An additional average yield of 0.31 pound of seed

per bushel of cones was obtained.

There are as yet relatively few cone-extraction

installations that use a continuous extraction

process. The Mt. Shasta Nursery in California

uses a tumbler-type, automatic seed extractor

with infrared heat. In Ontario, Carmichael (22)

has successfully used infrared lamps for extracting

pine seed. The method is entirely feasible where

power rates are low.

10

Species

Fahrenheit

temperature 1

Relative

humidity

Time

in

kiln

Amount

of cones

per

tray 2

White pine

Red pine _

Degrees

'140

150

150

130

150

130

130

Percent

41

18

18

38

27

24

38

Hours

4-5

7

4-6

4

4-6

4-5

4

Bushel

Jack pine

White spruce

Black spruce

Tamarack

White-cedar

1 Wet bulb temperatures are held at about 92° F. for

tamarack; 100° for red pine and jack pine; 102° for white

spruce and white-cedar; 109° for black spruce; and 112®

for white pine.

2 Size of trays is 36 by 48 by 1% inches.

At the Badoura State Nursery at Akeley, Minn.,

seeds of pine and white spruce are extracted by

placing cones in a cylindrical drum 4 feet in diameter and 15 feet long. Its exterior is covered with

)^-inch mesh hardware cloth. The drum is turned

at about 5 rotations per minute for 4 to 6 hours.

Heat, from a furnace in the basement, in the range

of 130° to 180° F. depending on species, passes

through the metal-encased cylinder. The extracted seed falls into a seed hopper and is not subjected to more and perhaps unnecessary drying.

Yields and costs in this operation are fairly well in

line with those of the usual type of kiln.

A rather good job of extraction of seed has

been accomplished without a kiln. Kindt (123)

dried 1,495 bushels of white pine cones by spreading them on the floor of a shed heated to 70° F.

The cones started to open on the second day and

in 1 week^s time were well opened. A seed

dealer at Stanford, Mont., opens Douglas-fir and

other cones by placing them on heavy Kraft

paper in the sun. Methods of extraction using

solar heat or room temperatures are cheaper

for some species than kiln treatment. They are,

however, often limited because of space or weather.

CONE SHAKER

After cones have been through the kiln, they

are placed in wire-covered shakers that are from

6 to 10 sided in shape, about 5 to 8 feet in diameter, and 6 feet long (fig. 3). The wire covering is

usually )^-inch mesh hardware cloth. Inside the

shaker, 1- by 6-inch slats increase the jarring

action on the cones and expedite extraction.

A metal jacket, vented to the exterior to remove

dirt, completely covers the shaker. The shaker

operates at about 13 revolutions per minute and

is usually powered by an electric motor.

Up to 5 bushels of open cones are put into the

shaker through a trapdoor, and seed falls into a

Agriculture Handbook 110^ TJ. S. Department of Agriculture
FiouRE 2.—A, Loading kiln trays

with cones. B, Two-unit cone

kiln designed by U. 8. Forest

Products Laboratory. (Chittenden Nursery, Wellston,

Mich.)

Forest Nursery Practice in the Lake States
F-;í!}2437

]''inuKE 3.—Cone shaker.

hopper directly below the revolving drum and

into bags or containers. These bags or containers

are sometimes located in the seed-cleaning room

on the floor level directly below. In some instances the seed is conducted by delivery tube

directly to the dewinger. Extraction generally

is more complete if only a 2- to 4-bushel charge

is used.

A continuous-process cone shaker, used at the

Chittenden Nursery at Wellston, Mich., is a

truncated cone-shaped screen 8 feet long, 3 feet

in diameter at one end and 2}^ feet at the other.

Cones are fed into one end and as the screen

rotates they work their way to the other end

in about 1 minute. The screen, powered by a 1-

hp. electric motor, rotates about 30 times per

minute. The time cones remain in the screen

can be regulated by changing the pitch of the

axis of the screen.

Once a batch of cones is extracted, the trapdoor

on the drum is removed, and empty cones are

discharged into a hopper leading to a storage bin

alongside the furnace. These cones usually are

burned as part of the fuel for the extractory

furnace. In some instances extracted cones of

red and white pines are sold to commercial

firms that use them for Christmas decorations,

wreaths, and table ornaments.

DEWINGING OF SEED

In Lake States nurseries, seed of conifers are

always dewinged but those of broadleaf species

usually are not. The seed are dewinged by

machines of various types or by being nailed in

sacks. A common machine design consists of a

cylinder of tight wire screen with an interior

rotating shaft to whicli four brushes are attached.

As the seeds pass between the revolving brushes

and the wire wall, the wings are rubbed off and

fall through the screen into a box below. The

cleaned seed works its way to the end of the

machine where it is collected in a trough. A

suction fan underneath the screen aids in removal

of trash.

The brushes must be of rather soft material

and the speed of the machine rather low. The

dewinger at the Hugo Sauer Nursery has a speed

of 44 r. p. m. Some conifer seed, notably spruce

and jack pine, are subject to injury by crushing

or bruising in the dewinging process as determined by Barton.^ Damage to red pine seed

from a dewinger speed of 120 r. p. m. was reported

in New York (46). When the speed was reduced

to 60, no damage occurred.

In a comparative test of dewinging jack pine seed

by machine and by flailing in sacks, it was found

that seed yields were slightly higher and germination somewhat better in the lot dewinged by

flailing. A study made at the Lake States Station

with jack pine seed showed a difference of 25 to

3 0 percentin real germination between the following

methods, ranging from best to worst: (1) rubbing

over a screen by hand or by power-driven brushes,

(2) hand rubbing, (3) beating in a bag, (4) leaving

wings undisturbed, and (5) trampling in a sack

and then putting through a small fanning mill (180).

Olson (108) removed wings of spruce seed with

a minimum of damage in a device consisting of a

drum of webbing or burlap revolving in a hammock of the same material. A heavy elastic band

kept the hammock under proper tension. This

ä Hugo Sauer Nursery, Rhinelander, Wis. Unpublished

annual report, 1938.

12 Agriculture Handbook 110, U. S. Department of Agricultit
method removed the objectionable feature of

rubbing the seed against metal with its attendant

danger of breakage or bruising.

The Badoura State Nursery near Akeley,

Minn., removes wings of pine and spruce seeds by

moistening them slightly and then tumbling them

slowly in a small concrete mixer. The tumbling

action removes the wings.

At the Cass Lake Nursery, Minn., seeds are

placed in a grain sack which is walked on slowly,

with a circular shuíñing motion.

By flailing in sacks, George {64) has successfully

dewinged American elm fruits and made them

adaptable for mechanical seeding. The seeds of

the ashes, birches, etc., are rather difficult to sow

mechanically unless dewinged. Therefore, they

are generally sowed by hand. Maple seeds, however, can be sowed mechanically after being

dewinged because they are more nearly spherical

than the long, tapered seeds of the ashes.

At the Mt. Shasta Nursery, Calif., pine and fir

seed are dewinged without injury by adjustable

brushes that revolve against a soft, corrugated

rubber mat.

FANNING AND CLEANING THE

SEED

Once the seed of conifers such as pines, spruces,

or firs has been dewinged, the mixture of seed,

wings, and pieces of broken cone scales is passed

through a Clipper cleaner equipped with interchangeable mesh screens of various sizes. As the

mixture of seed and debris moves over two

slightly tilted screens, controlled wind velocities

aid in separating chaff from seed. A number of

runs, usually four, must be made before the seed is

quite clean. With very light-seeded species,

particularly white-cedar, no fan is used.

Screen sizes used in the fanning mill at the

Chittenden Nursery for some of the more important Lake States conifers are as follows: (1) For

white pine, a Chaffer Type A screen is used in the

bottom on all runs, with a No. 13 or 14 top screen

on the first run and a No. 12 top screen on succeeding runs; (2) for red pine, the Chaffer Type A

screen is used in the bottom on all runs, with a

No. 13 top screen on the first run and a No. 10

on succeeding runs; (3) jack pine, being smaller

than red pine, requires a Ke-inch screen in the

bottom on all runs, with No. 10 and No. 8 top

screens for the first run and succeeding runs,

respectively; (4) for white spruce, Ks- and K2-inch

screens are used in the bottom for the first and

successive runs respectively, while No. 8 and No.

6 screens, respectively, are used in the top.

If the seed have been moistened before the

dewinging process, the mixture of seed and wings

must be predried at about 80° F. for 16 hours.

After being fanned, the seed must again be

checked for moisture content, which generally will

be about 10 to 12 percent. Pine and spruce seeds

may require some additional drying to reduce the

Forest Nursery Practice in the Lake States

408189°—57 2

moisture content to about 5 to 10 percent.

Canadian practice is to lower the moisture content

of pine and spruce seeds to some 3 to 6 percent

before placing in cold storage in sealed containers {21).

SIZE OF SEED IN RELATION TO

GERMINATION AND SIZE OF

SEEDLINGS PRODUCED

It has been a general observation that the

larger seeds within any lot germinate better than

the others. Deen {41) found that only 0 to 4

percent of the lightest 11 percent by weight of

longleaf pine seed germinated, while 52 to 100

percent of the remainder of the seeds were viable.

For the great bulk of this seed, germination was

more than 96 percent.

Tests on red pine at the Hugo Sauer Nursery

in Wisconsin indicated that the larger seeds

germinated better but did not produce larger than

average seedlings. If there is any advantage in

seedling size in trees produced from larger seed,

it generally disappears within 18 years after field

planting and usually much sooner {86, 180).

The low germination of the smallest seeds is

an incentive for sufficient additional screening

and cleaning lo remove the poorest fraction.

However, there would seem to be no need in the

Lake States to grade seed into several sizes before

sowing it in the nursery.

EXTRACTING SEEDS OF DRYFRUITED BROADLEAF SPECIES

The fruits of broadleaf species are first dried

and then handled by various methods to extract

the seed. Fruits of some species, such as maples,

ashes, basswood, birches, and beech, are rubbed

through hardware screens after sticks and leaves

have been picked out. This treatment separates

the clusters of seed or breaks up the strobiles of

birches. Fanning or running the seed through a

clipper mill will remove the remaining debris.

With the oaks and similar species, nothing need

be done except to remove debris such as sticks,

stones, and leaves. Acorns require no predrying,

and they are damaged by excessive drying.

Preferably, acorns should be sowed shortly after

collection.

Fruits of black locust and other similar legumes

can be run dry through a macerator {4-7) or

through an ordinary farm threshing machine.

Sanford {135) used the latter in extracting the

seed from 3,000 bushels of black locust pods which

yielded 6,471 pounds of seed, 6,120 of which was

classed as grade 1. Using a 4-man crew, 2 men

opened bags, 1 fed pods into the machine, and

1 measured and sacked the seed. The threshing

operation required 54 man-hours. The seed was

fanned before sacking, using No. 4 screen on top

and No. 12 below.

13
EXTRACTING SEEDS OF PULPYFRUITED SPECIES

Seeds of pulpy-fruited species (juniper, mountain ash, plum, etc.) are extracted if the fruits

are macerated in water and then the pulp floated

off. Such fruits may be softened for a few days in

water—changed several times daily to prevent

fermentation—before they are run through the

macerator. After extraction, juniper seeds can

be cleaned further in a solution of lye that helps

remove the pitchy outer layer of resinous material.

Black walnut seeds can be extracted readily if

the seeds are run through a corn sheller to remove

the husks. This method was mentioned as early

as 1900 by Sudworth (164)^

The Soil Conservation Service Nursery at

Winona, Minn., used a hammer mill to extract

seeds of pulpy-fruited species.^ The mill was run

at a speed of about 400 r. p. m., by means of a

farm tractor with flat-belt drive. The fruits were

poured into the mill with ample quantities of

water supplied by 1 or 2 garden hoses and left

there for 3 to 5 minutes. The cleaned seeds were

retained in the bottom of the mill on a screen,

along with some of the debris. After treatment

the seeds and pulp were dumped on screens to

dry. Then the material was run through a fanning

mill to remove the seeds from the debris. Juniper

6 Information furnished by Thor Bergh, former Nursery

Superintendent.

fruits can be depulped by this method except

that the seeds must be left in the mill for about

20 minutes.

YIELDS AND COSTS OF SEED

EXTRACTION

Seed yields per bushel of cones vary by species

and quality of cones. Some typical cone and

extraction costs are given in table 6. There is

considerable variation in the amount of seed

obtained per bushel not only between species but

also within species. For instance, in red pine the

yield ranged from 7.3 to 14.3 ounces per bushel

with a very close relationship between yield and

cost per bushel—the higher the yield the lower

the cost.

Johnson (73) reported that it required 0.97

man-hours per bushel to handle pine cones and

extract seed from them.

Cone costs per bushel in the 5-year period

1948-52 in the Lake States were as follows:

Red pine, $3 to $10; white pine, $1.50 to $4.20;

jack pine, $3 to $8; white spruce, $7 to $12; black

spruce, $10 to $12; and balsam fir, $4.

Costs for some nonconiferous seeds were as

follows: Eastern redcedar, $3.45 per bushel of

berries; white oak, $2.50; red oak, $3.70; black

walnut, $0.70 per bushel not hulled; and silver

maple, $0.50 per bushel.

TABLE 6.—Costs and yields in extraction of cones over a 4-year period at several Lake States extractories

Extractory and species

Bushels

extracted

Average

price

per

bushel

Seed obtained

per

bushel

of cones

Cost per

pound of

clean

seed

Year

of

crop

Class of cone crop

Chittenden:

Red pine

Number

721. 2

646. 3

155. 1

573.0

734 0

39. 7

200. 0

445.5

113. 0

235.2

1, 556. 0

583. 3

454 0

1, 534 3

23.9

885. 3

261. 0

10. 75

11.0

6. 0

Dollars

5.00

5.00

6. 00

6.00

1.75

1.75

2.00

2.00

3. 00

3.00

5. 00

6.00

1. 50

1.50

7.00

7.00

3. 50

3. 00

4. 00

Ounces

14. 3

12. 7

7. 3

10.0

15. 5

11. 1

13. 4

13. 4

9.0

6. 1

11. 3

11.7

10. 2

12.8

9.0

10. 5

11. 8

16. 7

32. 0

2 18. 6

Dollars

8.76

9.00

17. 46

11. 89

4. 16

6. 78

3.90

4. 18

8.52

12. 15

8. 57

11. 60

4. 90

3.58

13.50

12.58

8.55

6.25

3.08

3 4. 34

1951

1951

1953

1954

1951

1952

1953

1953

1951

1952

1951

1953

1951

1953

1953

1954

1948

1951

1952

1952

Good.

Do --- Do.

Do Poor.

Do_ -

White pine

Fair.

Good.

Do Poor.

Do Bumper in some areas.

Do

Jack pine Good.

Do _ Poor.i

Hugo Sauer:

Red pine Good.

Do- Fair.

White pine Do.

Do Good.

White spruce Poor.

Do _ --

Good.

Norway spruce Do.

Do Fair.

Balsam fir Poor.

Wli 1 tp-fipd ar Good.

1 About 75 percent of cones were 2 or more years old.

2 This seed was not dewinged; all other lots were.

3 Cones picked by prison crew, hence cost is not typical or comparable with others.

14 Agriculture Handhook 110^ Ü. S, Department of Agriculture
SEED STORAGE

After extraction, the moisture content should

be determined for any seed, particularly of conifers, scheduled for several years' storage. A

moisture content of 5 to 10 percent is preferred

for the seeds of pines and spruces used in Lake

States nurseries. Kiln-dried seeds often have

about this moisture content and may need no

further drying. If the seeds are still too moist,

they should be returned to the kiln for further

drying.

In Lake States forest tree nurseries seeds

usually are stored in one or more of the following

three ways: (1) Dry cold storage in sealed containers; (2) dry storage at room temperature;

(3) moist cold storage.

Dry Cold Storage

In the larger Lake States nurseries, seed

usually are stored in specially constructed seed

storage houses. The seed house at the Hugo

Sauer Nursery, for example, is a frame structure

with cinder block walls. It has a fir floor laid

over concrete which, in turn, is on a cinder fill.

The ceiling is of 1-inch insulation board with a

2-inch blanket of mineral wool. The temperature in this unrefrigerated seed house on a warm

day was found to be 23° F. cooler than the outside

temperature in the shade.

Dry cold storage at 33° to 40° F. in sealed

containers is best for prolonged storage of seeds

of all pines, spruces, firs, birches, ashes, whitecedar, junipers, larches, basswood, and hemlock. Usually the seed are stored in cylindrical

cans about 36 inches high and 18 inches in diameter, with an approximate capacity of 150 to

160 pounds of conifer seed. These cans are

sealed with a rubber gasket and a bronze screw

cap. Small batches of seed can be stored handily

in 5-gallon, rectangular oil cans that hold about

20 pounds each.

Seeds of red and jack pines have been stored

for 5 years in northern Wisconsin under situations

where summer temperature in the storage chamber was as high as 50° to 60° F., with a reduction

in germination of as little as 5 to 10 percent.

Balsam fir seed, however, rapidly loses its viability

in a few years unless held at 40° or below.

Red pine and white spruce seeds with moisture

contents of 6 to 10 percent have been held for 10

years in dry cold, sealed storage with only a 5- to

10-percent drop in germination.

George {öJj) was able to store American elm

seeds for a full year in open as well as closed

containers, after first drying them for 2 weeks

over sulfuric acid. Storage at 0° C. was better

than at 10° or 20°.

Dry Storage at Room Temperature

The seeds of some species, such as black locust,

other legumes, and basswood, can be stored under

rodentproof conditions at room temperature for a

year or two without serious losses in viability.

Seeds of pines and spruces native to the Lake

States area can also be so stored, although their

very high per-pound value warrants cold storage to

hold germination at a maximum.

Moist Cold Storage

Seeds of certain species of Lake States trees,

such as the oaks, black walnut, hickories, beech,

and silver maple, must not be dried and should be

kept at a moisture content above 35 percent. If

they are allowed to dry out, they promptly lose

their viability. By far the simplest and safest

way to handle them is to simulate nature by

sowing promptly after collection.

If for some reason the seeds cannot be sowed

until spring, they can be held in cold moist

storage, stratified in moist sand at temperatures

of 33° to 50° F., placed in outdoor pits, or held

in a root cellar for overwinter storage {77^ 150^

170). If outdoor pits are used, a well-drained

area of sandy soil should be selected and the seed

stratified in 2 or 3 parts of moist sand to 1 part of

seeds in boxes covered with rodentproof hardware

cloth. The upper part of the boxes should be

about 8 to 12 inches below the level of the top of

the covering soil. If 3-inch layers of soil and

straw are alternated for the topmost covering,

the buried boxes can be removed more easily in

early spring even if the soil is frozen. Seeds

stratified over winter must be removed promptly

in early spring to avoid premature sprouting in

storage and subsequent deformation of the seedlings in the nursery.

SEED DORMANCY AND

PRETREATMENT

Some tree seeds, such as those of jack or red

pines, germinate promptly after spring sowing

without any pretreatment. Other seeds, such

as those of white pine and white spruce, have

embryo dormancy and will have rather low

germination and a prolonged germination period

if sowed dry in the spring. Dormancy can be

overcome by a period of cold moist stratification

during which certain chemical changes take place

in the seed, making it ready for prompt germination. It should be clearly understood that

stratification is a method of treating seed to make

it germinate more promptly once seeded in the

nursery. It is not to be regarded as a means of

storing seed for 1 or more years. Expensive

Forest Nursery Practice in the Lake States 15
lots of seed have, on occasion, been ruined because

stratification was mistaken for storage.

Embryo dormancy ordinarily can be overcome

by fall seeding which often provides the necessary

cold moist pretreatment. However, stratifying

the seed in moist sand or peat for a period of 30

to 120 days (depending on species) at temperatures of 40° to 50° F. immediately preceding

spring sowing {166, 180) will bring about prompter

and often fuller germination.

Seeds of some tree species with tough or

impermeable seedcoats have seedcoat dormancy.

Black locust, for example, has a seedcoat so

impervious that water absorption is very slow and

germination may straggle along for several months

after seeding. Seedcoat dormancy can be overcome by mechanical or chemical treatments that

break, soften, or etch the impervious seedcoat and

make it readily permeable to moisture. Seeds of

some species, for example, must increase from

about 7 percent to about 45 to 65 percent in

moisture content before they can germinate {180).

Seeds with impervious coats usually are scarified

by (1) tumbling them in a drum lined with sandpaper or blowing them against a curved surface

lined with sandpaper, (2) immersing them in

concentrated sulfuric acid for a specific period

depending on the species, or (3) pouring boiling

water over them.

Black locust seeds vary considerably in seedcoat

dormancy. Some lots may be treated satisfactorily with boiling water, while others require

acid treatment for 30 minutes, more or less, or

mechanical scarification (4, 42^ 192). Mony

{100) suggests testing each lot of black locust

before pretreatment, using variable periods of

soaking in acid and a swelling test as an indicator

of the best method. He warns that seed should

not be stirred too vigorously during or after acid

treatment, that it should be washed thoroughly

after treatment, and that the temperature of the

acid containers during treatment should be held

down to avoid damage to the seed.

Chapman {26) used a modified Ames scarifier

consisting of a 12-inch forge blower with a 1-hp.

electric motor to blow black locust seed against a

6- to 8-inch-wide curved surface lined with No. 3

garnet paper. A fan speed of 1,700-2,200 r. p. m.

was required. With this device he obtained continuous scarification at the rate of 1 bushel per

minute.

Disk scarifiers are useful for small or experimental lots of seed {158).

Drum scarifiers were successfully used by Dayharsh {40) in treating eastern juniper seed, but

other methods of seed treatment have now superseded this drum-scarification procedure.

Seeds of certain tree species, such as basswood

and eastern redcedar, have both seedcoat and

embryo dormancy. Such seeds may require a

combination of scarification and stratification

(or fall sowing) to get germination the following

spring.

Basswood seeds are among the most difiicult to

germinate promptly. Under the ordinary practice of fall seeding only about 5 to 10 percent of

the seeds germinate the following spring, with an

additional 30 to 50 percent coming up the next

spring. Methods recommended to date for Lake

States nurseries have not proved successful.

A recently developed procedure, not yet tested

in Lake States nurseries, is as follows {72): (1)

Soak fruits in water for 3 days and then dry them

superficially; (2) immerse fruits in sulfuric acid

(technical grade), stirring vigorously for about 4

minutes, and cool down to 130° F., then leave

them for about 40 minutes; (3) force fruits

through a 4-mesh screen and catch material on

an 8-mesh screen, flushing well with water to

remove acid; (4) dry seeds and pericarp fragments

on absorbent material; (5) separate seeds from

debris by passing latter through 8-mesh screen;

(6) air-dry seeds thoroughly and immerse in concentrated sulfuric acid for 10 to 15 minutes, then

rinse thoroughly with water; (7) stratify seeds in

moist sand or peat at 36° to 40° F. for 110 to 130

days.

Uniformly successful germination of eastern

redcedar has been obtained in Soil Conservation

Service nurseries'' by collecting the seed in late

August and sowing it no later than the first week

in September. The soil is mulched to keep the

seedbed in moist condition. The seeds generally,

germinate promptly the following spring.

SEED TESTING

Accurate tests of the number of seeds per pound,

purity, and germination percent are necessary in

order that seed can be sowed in the nursery at

rates that will assure approximately the desired

stand per square foot. Thin stands waste space

and increase stock costs. Overdense seedbeds

produce undersized, spindly stock with a high cull

percent and poor survival or growth.

For test purposes, samples are generally taken

out of each large container of seed, or at least out

of each large lot of seed, for a specific year and

place of collection. The seed are drawn out of

the containers with a long, brass sampling tube

specially designed for this purpose. The tube

takes a uniform, equal sample from top to bottom

of the container. Several tubefuls, or enough to

constitute several ounces of seed, are needed for

an adequate sample of each 50- to 100-pound can

or separate smaller lot. This sample then must

be subdivided until a small representative sample

of 2,000 to 3,000 seeds is obtained. The sample

can be subdivided with a mechanical device or

by being successively quartered and mixed.

Purity of seed is expressed in percent and is

determined by the formula:

Purity=: Weight of clean seeds X 100

Weight of seeds plus impurities

7 Information furnished by Thor Bergh, former nursery

superintendent.

16 Agriculture Handbook 110^ U. S, Department of Agriculture
Each seed must be inspected to separate the

apparently sound seeds from the chaff, broken

wings, needles, and other debris. Purity should

generally be above 95 percent for most tree seed.

In some species, such as balsam fir, seed purity

may be low because of difficulty in removing

fragments of cone scales that are similar to the

seed in size and specific gravity.

Because the nurseryman normally sows the seed

as it comes from the seed container, he should

know the number of seeds per pound. He can

obtain this information by weighing in grams on a

sensitive balance a small sample of uncleaned seed

and then accurately counting the number of whole,

apparently sound seeds in the sample. A formula

for determining clean seeds per pound follows:

Clean seeds per Number of clean seeds counted X 454

pound of unclean seeds Weight of unclean seeds in sample, in grams

In this formula, 454 is the number of grams per

pound.

Sometimes the seeds are cut open to determine

what proportion is filled. Cutting tests are useful

as emergency guides in fall sowing of freshly collected seed that have embryo dormancy, or for

other seed that have not been tested for germination. Cutting tests are particularly useful if

previous experience sho,ws the results of past

cutting tests together with the number of seed per

pound and the germination or tree percent. In

cutting tests, several hundred representative seeds

usually are split with a sharp knife. Large-seeded

species, such as walnut or hickory, can be cracked

in a vise. Good seeds are well filled and have

white or cream-colored kernels.

Stains can also be used to determine viability,

and they are more reliable than visual estimates.

For example, indigo carmine will not affect the

color of viable seeds (98), but it will stain dead or

injured embryos (180).

Germination can be determined best if the lots

of seed are sown in sand flats, each flat usually

containing 200 or 250 seeds of any one individual

lot. The flats are filled with washed and sterilized

fine sand. A small board that fits just inside of

the flat is used to level the sand to sowing depths

from % to 1 inch below the top of the flat. The

exact number of seeds is counted out and broadcast uniformly over the sand. The seed is then

pressed lightly into the surface, sand is sifted over

it, and the surplus struck off with a slat to obtain

uniform depth. The flat is labeled with a metal

tag showing collection or accession number.

Germination tests in the Lake States are generally made on 4 or 5 replicated samples of 200 to

250 seeds each, with each replication occurring

in a separate flat. A flat usually contains four

separate properly labeled lots of seed. The reason

for having each replication in a separate flat is to

reduce the odds of having damping-off disease

wipe out all replications. This is more likely to

happen if all replications are in the same flat.

Some investigators recommend 8 replications of

100 seeds for each lot (183). This has the advanForest Nursery Practice in the Lake States

tage of providing a better average germination

percent, especially if results of 1 or 2 replications

have to be discarded.

For species with prompt seed germination, the

sand flats are placed in a greenhouse or in a germination room that can be lighted during the normal

daylight hours and heated to provide a diurnal

fluctuation from about 68° F. at night to 86°

in daytime. The flats should be watered daily.

Dormant seeds must be properly pretreated before germination will start. The seeds can be

chilled before sowing or, after sowing, the entire

flat can be placed in a cold room at the desired

temperature and left there for the period needed

to break dormancy. The flats must be watered

often enough to keep them moist while in the cold

chamber. Where large cold-storage chambers are

not available, the seed sample can be stratified

or mixed with a small quantity of moist peat or

sand, wrapped in cheesecloth, and placed in glass

jars in an ordinary refrigerator set to the proper

temperature.

Once germination starts, the seedlings can be

removed every 1 to 3 days and recorded. Ungerminated seeds remain in the flats until germination appears complete, usually 30 to 60 days.

Once germination is completed, the results of

the 4 or 5 replicated samples are pooled and averaged. If 1 or 2 of these appear badly out of line

with the average of the remainder, their results are

discarded provided there is evidence of preemergent damping-off or similar trouble. As a

general rule, results of all replications should be

used in computing an average.

One can also test germination by placing the

seeds between moist blotters in petri dishes. It

is desirable to have three glass rods or pieces of

glass tubing about three-sixteenths inch in diameter in the bottom of the petri dish to support the

layer of blotter paper. The water level should

be maintained at the approximate level of the

blotting paper. Petri dishes, blotters,' and glass

rods should be sterilized with heat or boiling water

to reduce the incidence of mold which is invariably

a problem with unsterilized petri-dish tests (172).

A Jacobsen germinator or similar device can be

used in lieu of petri-dish tests (180).

Peat mats have not been used in the Lake

States but they have been widely employed in

the South. They probably would work equally

well in the Lake States.

APPLICATION OF GERMINATION

TESTS TO NURSERY SEEDING

Eighty to ninety-five percent of freshly collected

tree seeds of good quality often will germinate in

the laboratory where conditions are nearly ideal

for full germination. Under nursery conditions,

however, germination usually is lower and the

proportion of seeds producing usable 1-0 seedlings is still less. This reflects such obstacles as

unfavorable moisture conditions, pre-emergent or

17
post-emergent damping-oflF, too deep a soil covering, heat injury, and other losses from rodents or

birds, or from cultivation and weeding damage,

which reduce germination or survival in spite of

extreme vigilance on the part of the nurserymen.

Usually the small-seeded species have lower germination and survival than the large-seeded

species (table 3, p. 8). With large-seeded species,

such as red oak or white oak, the ratio of 1-0

nursery stand to laboratory germination may be

as high as 0.95. This means that about 95 1-yearold seedlings can be expected for every 100 viable

seeds sown, based on laboratory germination tests.

With pines and spruces the ratio is usually from

0.40 to 0.70; with birches it may be only 0.12 to

0.15.

Individual nurseries often have experience

tables giving ratio of 1-0 nursery stand to laboratory germination, as well as the number of trees

produced per pound of seed sown. In their absence the data in table 3 will serve as a general

guide to determine sowing rate.

18 Agriculture Handbook 110, Ü, S, Department of Agriculture
HOW TO SELECT A NURSERY SITE

Careful consideration must be given to the

selection of the nursery. A level, or nearly level,

well-drained site suitable for production of seedlings or transplants should be chosen in or near

the area where the trees are to be planted. Rolling, hilly areas are unsuitable for forest nurseries.

A detailed discussion of the important factors

affecting the selection of a nursery follows.

CLIMATE

The nursery should be located close to, or

slightly south of, the areas where the trees will

be field-planted. If the nursery is located too far

to the north, frozen soil may make it impossible

to dig trees at the very time when conditions for

field planting farther south are at their best. The

frequency of late spring frosts should not be overlooked. They are likely to be more severe in

basins or other low areas known as ^^frost pockets.''

TOPOGRAPHY

Level or nearly level areas are desirable so that

comparatively little money will need to be spent

for grading and leveling. Then too, mechanical

equipment, such as nursery lifters and transplanting machines, works better on level ground and

erosion is less of a problem.

For conifer seedbed areas, maximum grades

should be no more than 1 or 2 percent. All

minor depressions where water will stand, even

for a few days, require leveling; otherwise seedlings

will drown out or be damaged by ice in the winter.

Such leveling is an expensive operation. For

transplant areas, grades of 5 percent are permissible if the slopes are long and gradual and the

topography is not rolling. However, when mechanical transplanters are used, slopes even of

5 percent can be annoying because of the tendency

of the machines to creep sideways and space rows

unevenly.

SOIL TEXTURE

For conifer nurseries, soils should have a siltplus-clay content not less than 10 nor more than

25 percent. Loamy sands or light sandy loam

with 15 to 20 percent silt-plus-clay are preferred.

For hardwood nurseries the silt-plus-clay content

may be as high as 35 percent. The soil must have

adequate surface drainage and the subsoil, preferably a fine sand or loamy sand, should also have

good drainage. The land should be quite free

from stones or coarse gravel. Large numbers of

boulders, rocks, or stones create serious problems

in cultivation, transplanting, lifting, and other

operations. Their removal can be very expensive.

Light, sandy soils are well adapted for conifer

production (188), and they offer the following

advantages in contrast to heavy soils:

1. Because they are easier to work, costs are

lower for ground preparation, seeding, cultivation,

weeding, and lifting.

2. The seeds can be drilled directly into the soil

surface; sand must be brought in for covering

conifer seedbeds in heavy soils.

3. Sandy soils thaw out sooner in the spring and

operations can begin earlier; they dry up sooner

after rains.

4. Frost heaving is less in sandy soils.

5. In lifting operations, there is less chance for

root stripping or breakage in Ught soils. Better

root systems are produced.

6. Sandy soils do not puddle or become flooded

as readily as heavy soils. Flooding even for a

period of a few days may drown out the small

trees, cover them with mud, or cause damaging

ice sheets in late winter.

7. The problem of regulating acidity is not as

serious on sandy soils.

Light soils have some disadvantages—they are

more droughty than heavy soils, require more

irrigation water, are generally lower in fertility

and ability to retain soil nutrients, and are somewhat subject to wind erosion. However, their

advantages for coniferous seedhng and transplant

production far outweigh their disadvantages.

SOIL FERTILITY

A nursery site should have soil adequate in

fertility. Based on numerous soil analyses in

forest nurseries where goQd stock was being

produced, the following are minimum standards

for the top 8 inches of soil: total nitrogen 0.08

percent; available nitrogen (nitrate and ammonia

nitrogen), about 20 pounds per acre; available

phosphoric acid (as P2O5), 50 pounds per acre;

available potash (as K2O), 125 pounds per acre;

Forest Nursery Practice in the Lake States 19
replaceable calcium, 3 milliequivalents per 100

grams; and replaceable magnesium, 1.0 milliequivalents per 100 grams.

For growing the conifers commonly planted in

the Lake States, the soil acidity should be between

pH 5.2 and 5.8. For hardwood-stock production,

a pH between 5.5 and 6.5 is desirable.

Tests of the soil should be based on at least 6

to 10 individual samples taken at random over

the proposed nursery site. For details on correction of deficiencies in nutrients in either new

or well-established nursery sites, see page 41.

VEGETATIVE COVER

In the absence of detailed tests, a reliable

method for selecting a nursery site is to pick an

area of well-drained, upland, sandy soil that

supports or formerly supported red pine, good-site

jack pine, or a mixture of white and red pines.

Such soils usually will be satisfactory in fertility

and texture for producing suitable stock, despite

the fact that they may currently support aspen

or paper birch which have followed past forest fires.

A forested area is considered more desirable for

a nursery site than is a cultivated agricultural

field of the same soil texture, for these reasons: (1)

the levels of fertility and organic matter usually

are better; (2) desirable mycorrhizal and favorable

soil organisms are more abundant; (3) weeds and

weed seeds are not so numerous; (4) diseases and

insect pests usually are not so serious. The

presence of a stand 40 to 70 feet tall also makes it

possible to leave standing strips or shelterbelts of

trees for protecting the nursery seedlings (figs. 4

and 6).

These advantages of wooded lands as nursery

sites do not preclude the use of former agricultural

fields. Such fields have made satisfactory nursery

sites, and the cost of clearing them was saved.

However, they often require large amounts of

peat, compost, duff, or other types of organic

matter. Another serious disadvantage of old

fields and pastures is that they often are infested

with quackgrass and white grubs (28).

WATER SUPPLY

Sufficient water must be available to provide a

sustained flow of at least 10 gallons per minute

per acre of nursery ground. It should not contain

more than 200 parts per million of dissolved solids

{47). This is equivalent to an electrical conductivity of about 330 microhms/cm. at 25° C. (1).

Preferably, the sodium absorption ratio of the

water should be under 10, and the boron content

less than one-half part per million (1).

Lakes, rivers, or streams reasonably free from

industrial wastes may be satisfactory, or a drilled

well may suffice. Water that is alkaline or heavily

polluted with industrial wastes is especially troublesome in conifer nurseries because it increases

damping-ofï and creates soil-fertility problems.

Likewise, if too heavily laden with organic matter

or mud, it wül clog the irrigation lines or oscillators

that turn them.

Before a source of water for a nursery is developed, it is advisable to consult the State geologist

about water-bearing formations—their depth, constancy of supply, and quality—and the State laws

concerning the taking of water from open bodies

of water or streams.

In the northern Lake States the large number

of lakes and streams and huge areas of waterbearing sands usually simplify the problem of

obtaining an adequate supply of water suitable for

F-442S57

FIGURE 4.—Note shelterbelts that provide wind

protection. (Griffith

State Nursery, Wisconsin Rapids, Wis.)

20 Agriculture Handbook 110, U. S. Department of Agriculture
FiGUKE 5.—Main road into

nursery is at right. It

provides for two lanes of

travel separated by a

parkway planted to a

shelterbelt. (Lydick

Nursery, Cass Lake,

Minn.)

nursery irrigation. In the southern part of these

States and in the prairie areas of Minnesota there

IS more of a problem because waters often are

alkaline or laden with mud or industrial wastes.

LABOR SUPPLY

There must be an adequate supply of labor near

the nursery site. From April to late September an

average of 3 laborers will be required for every 10

acres of land in nurseries producing seedlings and

transplants for reforestation. In spring peak

periods, such as late Apru and May, 8 to 10

laborers per 10 acres of nursery must be available.

Women and girls have proved adept at some of the

nursery tasks such as transplanting, weeding,

sorting, and grading. They have made up 50 percent or more of the labor force in some of the

Federal nurseries.

TRANSPORTATION AND

COMMUNICATION

The nursery should bo so located that it has easy

access to railroads and highways (fig. 5). Since

some State and private nurseries often ship the

bulk of their stock by rail express, closeness to a

railhead is advantageous. Federal nurseries which

usually ship most, if not all, of their production by

truck directly from the nursery to the field planting

site must be located on or near all-weather roads.

Motortruck shipments by common carrier, or on

l)i<ls by private truckers, provide a speedy, efficient

m(>thod of shipping nursery stock. Telegraph and

telephone facilities must be available to the nursery

for exjjediting shipments and transacting other

required business. It is also necessary that

modern nurseries be located on or near a powerline.

Forent Nursery Practice in the Lake States

NEARBY SOURCES OF PEAT AND

SPHAGNUM MOSS

It is highly desirable to have adequate, easily

accessible sources of peat and duff for fertilizer and

compost, and sphagnum moss or shingle tow for

packing material. Nearby sources of sand also

are useful for stratifying seed or covering seedbeds.

Sand used for covering seedbeds should be acid in

reaction; if it effervesces when treated with a few

drops of a 10-percont solution of hydrochloric or

sulfuric acid, it should not be used.

SIZE OF AREA AS RELATED TO

PRODUCTION NEEDS

The tract selected must be large enough to

accommodate anticipated production needs.

About K to Yi of the total area can be devoted to

growing trees each year, and the other )i to % of

the area should be available for growing a soilimprovement or cover crop, such as legumes or rye.

The minimum size for a fairly large-scale public

nursery is about 20 acres, which gives a production

capacity of 3 million seedlings and transplants.

For a corporation or private nursery, the minimum size is about 10 acres.

To compute the space required for a nursery, the

production of usable plants per square foot of

nursery bed must be known. Conifer seedbeds

usually wUl produce about 50 plantable seedlings

per square foot. Mechanically transplanted conifers usually are spaced 2)i inches apart in rows 7 or

8 inches apart and commonly yield about 8 plants

per square foot. Only about 75 percent of the

nursery bed area is actually available for production, the remainder being in paths, ends of beds,

and turning areas.

21
The net space requirements vary for different

classes of coniferous nursery stock (table 7).

Seedling hardwoods, grown usually as 1-0, 2-0,

or 3-0 for field planting,^ produce about 10

plantable trees per square foot and hence require

5 times the net area estimated for seedling conifers

of the same classes of stock.

Because they vary in inherent characteristics

and in their requirements for light and space, the

species as well as the class of stock will influence

the size of the nursery required to produce a given

amount of stock. This subject is discussed in

more detail on page 61.

The size of the nursery to be developed will also

be governed by the possibilities of expanding

production and the provision for adequate rotation

of the nursery blocks so that proper soil maintenance practices can be carried out.

8 Forest nursery stock is known by a numerical system,

the first number representing number of years in the seedbed and the second, number of years transplanted. Thus,

1-year-old seedlings are called 1-0 stock, and 2-year-old

seedlings transplanted at the end of the second year and

grown 1 year in the transplant beds are known as 2-1 stock.

TABLE 7.—Net space requirements per million

conifer seedlings, excluding nonproducing areas

such as paths, turn areas, and roads ^

Class of

Net area required—

stock

1st

year

2d

year

3d

year

4th

year

5th

year

Total

l-0__

Acres

0. 46

.46

. 46

. 46

.46

. 46

. 46

. 46

.46

Acres Acres Acres Acres Acres

0. 46

2-0 5.46

.46

2.87

. 46

2.87

. 46

.46

.46

. 92

3-0 0.46 1. 38

1-1 3. 33

2-1 2. 87

2.87

2.87

. 46

2. 87

3. 79

1-2 6. 20

2-2 ___ _ 2.87

2.87

2. 87

"2."87~

2. 87

6. 66

3-2

2-3

7. 12

9. 53

1 Assuming 50 plantable seedlings produced per square

foot, and 8 plantable transplants per square foot. For

computation of gross area required, multiply the net area

in this table by 1.33 since this allows adequate margin for

nonproductive areas.

22 Agriculture Handbook 110, Ü. S. Department of Agriculture
DEVELOPMENT OF THE NURSERY SITE

An accurate survey of the nursery site and the

preparation of a topographic map should provide

the basis for a detailed development plan. Some

of the primary points to be observed in making the

plan are as follows: Location of buildings with

reference to the niu-sery area; the layout of water

distribution system ; size of subdivisions of nursery

area to allow efficient use of machinery; and the

location of roads and interior windbreaks which

should take up a minimum of space and yet allow

the most efficient use of the nursery. In regions

where snow removal is a problem, particular

attention should be given to locating the nurseryman's residence near main highways and other

buildings.

SUBDIVIDING THE NURSERY

For efficient and economical management, the

nursery should be divided into blocks or compartments of convenient size. Further division of the

compartments will depend upon the practices and

methods to be used.

Since much of the nursery work lends itself to

mechanization, there should be sufficient space at

the ends of the compartments to turn motorized

equipment. This area usually serves a dual

purpose, i. e., for turning space and for roads for

easy access to various points in the nursery. The

width and length of beds to be installed will play

an important part in determining how the nursery

should be subdivided into compartments.

The seedbed width accepted by most nurserymen is 42 to 48 inches. The length varies, depending on the size of the compartment, but a maximum length of 525 feet is recommended where

overhead irrigation is planned. Although subdividing the compartment into units is not important where flooding or a temporary surfaceirrigation system is to be used, it is extremely

important that attention be paid to planning and

laying out these units if a permanent irrigation

system is to be installed.

WINDBREAK PROTECTION

To reduce the eroding and drying effect of strong

winds, interior windbreaks often are needed.

Nurseries of only a few acres seldom require them,

but they are essential for nurseries of 20 acres or

more. Windbreaks can be provided by leaving

strips of natural tree growth (fig. 6), or by planting

strips of trees at strategic locations throughout

the nursery. They should be located on the

windward side of the nursery and parallel to the

beds to give maximum protection and yet not

interfere with nursery operations.

Because planted hedges or windbreaks do not

afford maximum protection during the first few

years after planting, natural stands should be used

wherever possible. It may be necessary to select

a species for windbreak-planting purposes that is

not commonly produced in the nursery, since some

States have laws against the use of the same

FIGURE 6.—^A natural windbreak of balsam flr,

black spruce, white

spruce, eastern hemlock,

white pine, and red pine.

When the site was cleared, these trees were left

in strips about 20 feet

wide to provide a natural

windbreak. (Manistique

Nursery, Mich.)

Forest Nursery Practice in the Lake States 23
species. Because of their small demand for field

planting, northern white-cedar, black spruce, and

junipers usually are acceptable for interior windbreaks in the Lake States.

If the selected nursery site has existing tree

growth, it is desirable to leave 20- to 30-foot wide

strips of standing trees, with a spacing of about

600 feet between the strips. A general rule is that

windbreaks have a zone of protection equal to

approximately 10 times their average height. In

the Lake States, one may expect ultimate heights

of 60 feet or more for pines. Hence, the zone of

reasonably good protection will be about 600 feet.

Natural strips of timber left as windbreaks

usually suffer considerable mortality from sudden

exposure, breakage, and uprooting in the development of a nursery site. In such cases reinforcement planting, preferably with red pine, white

spruce, or black spruce, is necessary.

If the prospective nursery site has no natural

growth, parallel shelterbelts or a gridwork of 3- to

5-row shelterbelts of red pine, jack pine, and white

spruce should be planted, using at least one row of

each and keeping the spruce on the outside. As a

supplement to this system, some nurseries use

additional shelterbelts of one row of white-cedar,

white spruce, or blue spruce spaced between the

larger shelterbelt rows. Some nurseries also use

interior hedges of trimmed white spruce or juniper

at intervals of about 100 feet. Because such

hedges suppress growth in adjoining seedbeds,

many nurserymen prefer to use slat-wire snow

fence supported on posts under every second

pipeline. The sapping effect of interior hedges

can be reduced considerably by severing their

lateral roots with a knife-blade trencher, a plow, or

rolling coulter run parallel to the hedge and several

feet away from it at 3-year intervals.

In nurseries where mechanical transplanting,

cultivation, and lifting are used, long beds or rows

are desirable; they should not be interrupted by

cross hedges or cross fences.

LAND DEVELOPMENT

The nursery should be carefully staked out on

the ground in accordance with the development

plan before clearing or leveling is started. The

areas to be used for tree production should be

defined, as well as the location of roads, natural or

planted windbreaks, building sites, and parking

areas.

Nursery development requires a variety of types

and sizes of equipment, depending upon conditions

on the site. Areas that have been in farm crops

or pasture do not present so serious a problem as do

those that must be cleared of brush, stumps, and

tree growth. To maintain uniform fertility, the

surface soil must not be disturbed more than is

necessary {71)-, therefore, heavy equipment such

as bulldozers should not be used for bunching the

trees and brush. Rather, it should be cut and the

stumps pulled or removed by blasting. The slash

should be hauled from the area and not burned in

place. ^ Burning creates a temporary alkaline

condition through release of potash and lime,

which may cause serious damping-off, and itdestroys some of the valuable humus.

The amount of leveling that is necessary will

depend upon the topography and the nursery

practices to be used, particularly the method of

irrigation. In any event, leveling should be held

to a minimum. Moving the topsoil complicates

the maintenance of a uniformly fertile nursery

soil. Therefore, when it is necessary to do a major

job of leveling, the topsoil should be pushed aside

and then spread back on the area after the subsoil

has been excavated. This operation can be

accomplished with a bulldozer, land plane, or road

maintainer.

When the site has been cleared, a heavy plow

especially designed for breaking new land should

be used. This type of plow is sturdily constructed

and stands up under use on land infested with

roots, small sturnps, and clumps of brush. After

being plowed, the land should be disked with a

heavy tandem disk to cut up the sod and hasten

deterioration of the vegetative material. Disking

should be repeated and followed by harrowing

with a spring-tooth harrow until the land is

thoroughly tilled. Pieces of stumps, roots, limbs,

and stones should be picked up and hauled off the

area. A spike-tooth harrow or drag can be used

very effectively in leveling the ground as the last

operation prior to placing the land in production.

Low areas, almost unnoticeable otherwise, often

can be detected readily after heavy rains.

It is very important that the nursery soil be in

good tilth and as free of weeds as possible for the

production of conifer seedlings. Therefore, pasturelands or areas that have been in heavy sod for

a long time preferably should be planted to a

cultivated crop or Kept fallow before being

converted to nursery use.

On areas that have considerable quackgrass,

repeated cultivation with a special cultivator is

necessary. One nurseryman solved this problem

by running a potato digger over such an area and

scooping up the quackgrass roots and stones with

a fork before doing the regular ground preparation

{28).

ROAD SYSTEM

An adequate road system, carefully laid out and

well maintained, is essential to efiicient operation

of a nursery. Major improvements such as warehouses, compost pits, and cone storage facilities

must be accessible. Where sufficient area is available and the layout of the nursery precludes planting windbreaks across the ends of the beds, a

double driveway with a hedge between the two is

a very satisfactory arrangement in the operation

of large nurseries (fig. 5, p. 21). Interior roads

should be wide enough to provide turning space

for tractor-drawn equipment. A 20-foot road

width is a minimum for operating and turning

24 Agriculture Handbook 110^ U. S. Department of Agriculture
most types of equipment. Thirty feet is recommended particularly for large nurseries where

mechanization of nursery operations is proposed.

An application of crushed rock or fine gravel

ordinarily is required for main roads. The surfacing should be confined as nearly as possible to

a 10- to 12-foot strip down the center of the road.

Care should be taken to keep the surfacing material from spreading onto the production areas

and becoming mixed with the nursery soil. This

is particularly important if the surfacing material

contains calcareous rock or fine materials that

would lower the acidity of the soil.

FENCES

A well-constructed fence around the nursery is

essential to protect the beds from livestock and

deer; it should include cattle guards to provide

easy access. For nurseries in the Lake States, a

heavy galvanized, woven-wire fence is recommended. This type requires slightly more maintenance than the ordinary barbed-wire fence, but

maintenance will be reduced if the posts are no

farther than 12 feet apart. Close spacing of posts

is particularly advantageous in areas where heavy

snows tend to pull the fence out of alinement.

PUMPING AND IRRIGATION

PLANTS

Because of the relatively light rainfall during

the growing season in the Lake States, some type

of irrigation is essential while the seeds are germinating and during periods of drought. Accordingly, an adequate supply of water should be

available at all times. Ordinarily, this is not a

serious problem in the Lake States because of the

large number of streams and lakes and the high

water table generally present.

An open water sou^rce has an advantage over a

well in that less investment is required to develop

it. Another advantage is that the nurseryman

can insure an adequate supply of water, to some

extent, by constructing a diversion dam on a

watercourse, by impounding a supply, or by

dropping the intake channel from a lake to the

pumping unit to take care of any fluctuation in

the lake level.

Well points may be adequate for small nurseries

but are not recommended where a large quantity

of water is required. Because of the frequent

fluctuations in the depth of the water table as a

result of long drought periods and the heavy

drain upon the underground water supply, it is

diflicult to maintain a satisfactory water level in

the ordinary shallow well or battery of well points.

Increasing the depth of the well as the water table

drops or constructing, at the outset, a deep well

equipped with a deep-well turbine pump will

overcome this difíiculty. A deep well usually is

more expensive than an open water supply and is

recom.mended only as a last resort.

Forest Nursery Practice in the Lake States

Pumping From Open Water Supply

Into an Overhead Irrigation System

Pumping units drawing from a lake, reservoir,

or stream should be placed a short distance back

from the water's edge and at least 3 feet above the

highest water level that is likely to occur. This

will permit the installation of a system for screening or filtering out small particles of sand or debris

that could clog the irrigation system. The water

should be pumped from a sump connected with

the main water supply by a canal or conduit. The

size of the sump needed will depend upon the

capacity of the pumping units. It should be

large enough to insure a constant supply of water

even though the flow through the connecting

channel may be reduced by the screens placed in

the channel. To insure a good head of water

passing through the filtration system, the bottom

of the sump should be from 4 to 5 feet below the

surface of the reservoir.

The number of screens required in a filtration

system is influenced by the character and amount

of material to be removed from the water. Ordinarily, 3 screens of different sized mesh, placed 16

to 24 inches apart in the channel, should suffice.

The first screen usually is of )i- or X-inch hardware

cloth and the second and third screens of much

smaller mesh, as ){&- and )áo-inch mesh which have

proved satisfactory for filtering out very fine

material.

Pumping From Wells

Water can be pumped from one or more well

points, or an open well, where the water table is

within 10 to 20 feet of the surface and the water

stratum is composed of sand and gravel. A

series of connected well points can be used effectively but an open, gravel-packed well is recommended because it is more efläcient and troublefree.

To construct a gravel-packed well (fig. 7), a

24- to 30-inch, or larger, blank casing is sunk first

to the full depth of the well. The fine material

is removed from inside the casing with a bucket

or dipper as the casing is sunk. Then a perforated

casing or well screen is placed in the center of the

larger casing. Coarse gravel is packed next to

the screen and fine gravel is placed at the outer

edge of the well. The level of the gravel should

be kept above the bottom of the outer casing as it

is raised to the top of the water-bearing strata.

A concrete slab 3 to 4 inches thick is poured on

top of the gravel to prevent infiltration of silt and

fine material into the well. A section of the outer

well casing is left in place to facilitate any maintenance work that may be necessary at a later

date. The suction pipe, equipped with a foot

valve and strainer and connected to the pump, is

placed inside the smaller well casing. This pipe

must be airtight and should be long enough to

reach within 8 to 10 inches of the bottom of the

well.

25
Concrete core

Water table

Fine screen

Water-bearing

gravel

Foot voive

FIGURE 7.—Details of a gravel-packed well.

Because of their simplicity, high efficiency, and

low operating and maintenance costs, horizontal

centrifugal pumps commonly are used in shallow

wells (fig. 8). The maximum suction lift of a

centrifugal pump is 18 to 22 feet, a fact to be considered in planning the water system. Singlestage pumps can be used where the required output is low and the total head is less than 150 feet.

The total head consists of the sum of (1) suction

lift, (2) discharge bead, (3) friction head, and

(4) velocity head. The latter can be ignored in

the ordinary installations. Wliere the total head

is more than 150 feet, and delivery of 200 gallons

or more per minute is required, a horizontal

multistage pump is generally recommended. Because the efficiency of this type of pump drops off

rapidly when the head varies from that for which

the pump is designed, the correct head should be

specified very carefully when purchasing the

pumping unit.

Where the vertical distance from the pump to

the lowest water level is more than the suction

lift, a deep-well pumping unit is necessary. Two

general types of deep-well pumps are in common

use. One, commonly used for wells where the

required output is small, is the plunger and

cylinder type. The other is the turbine type

(including centrifugal, auger, and jet pumps), and

it is used where the required output is large and

pumping must be continuous. As a rule, the

turbine-type, deep-well pump has a higher initial

cost, but, in most cases, this can be justified by

low operating costs and long life of the pumping

unit. Vertical, multistage, turbine-type pumps

have been in use in U. S. Forest Service nurseries

for a number of years and have given satisfactory

service.

Because they are simple to operate, electric

motors ordinarily are recommended as a source of

power for pumping imits. However, power costs

should be investigated thoroughly and operating

costs determined carefully before deciding on the

installation of electric motor-driven pumping

units. Squirrel cage, induction, open-type electric motors, designed for operation on 3-phase,

60-cycle, 440-volt current, are recommended

where electric power is used.

A gasoline engine power unit usually is cheaper

to install and operate than either diesel or electric

units, and it is recommended for the average

nursery. The industrial-type gasoline engine

should be chosen instead of an automobile engine

because it is more compact, more sturdily constructed, and a more efficient power unit. In

order to insure against serious losses in the seedbeds by drought or heat as a result of a breakdown of the pumping unit, a standby unit should

be installed.

FIGURE 8.—Pump on right

is a 225-gallon-per-minute, double-suction centrifugal, driven by a

15-hp., single-phase, electric motor. Pump on the

left is of the same type

and capacity but made

by a different manufacturer.

¿Ö Agi'icutture Handbook 110, Ü. S. Department of Agriculture
Distributing Mains

A well-designed system of water mains for

distributing water to the various sections of the

nursery is required for overhead irrigation. Because irrigation equipment is not in use during

the winter, the pipes need not be put down below

the frostline provided they are installed on a

slight gradient to permit draining the system in

the fall. A convenient depth is 18 to 24 inches,

which places the mains below the plow level and

affords adequate support for the risers. To provide for the contraction and expansion due to

temperature changes, an expansion joint should

be included for every 1,000 feet of main.

The size of pipe used in the system varies with

the size of the nursery, the overall length of the

mains, and the amount of water to be delivered.

For a typical 20-acre setup, 6-inch pipe is used

first; after about 600 feet, a 4-inch size is used,

and 3-inch lateral pipes are placed at right angles

to the 6- and 4-inch pipes. A nursery layout of

the water-main system for a nursery of about 50

acres is shown in figure 9.

Ordinarily, it is not necessary to sprinkle the

entire nursery at one time and, in any event, it is

not practical to install pumping facilities of

sufficient capacity to operate all of the overhead

lines simultaneously. The number of lines that

should be considered will depend upon the ability

of the proposed system to supply those farthest

from the source of supply. It is helpful in laying

out a water system to know the frictional losses

in pipes of various sizes and different discharge

rates per minute (table 8).

The following data are necessary in determining

the pipe sizes needed when water is pumped from

a well or reservoir through a system of mains and

distributed through overhead irrigation lines:

1. Working pressure required at the most

distant unit served. Pressure in pounds per

square inch can be converted to feet of head by

multiplying by 2.31.

2. The flow in gallons per minute required at the

most distant unit served.

3. Elevation difference in feet between the

water level at source of supply well or reservoir and

the point of discharge.

4. Loss in head resulting from friction as the

water flows through the pipe (see table 8).

5. Total head in feet required to deliver the

water to the point of discharge. This is the summation of the head at the outlet plus elevation

head and friction head loss expressed in feet.

Example: Assume 800 feet of pipe, including the

intake pipe, is required to deliver 200 gallons per

minute to the farthermost section to be served;

the pressure required in the pipe at the discharge

point is 30 pounds; and the difference in elevation

between water level and point of discharge is 15

feet. The total head in feet then becomes^—

Head (pressure) at point of discharge (30 x 2.31)_ 69 feet

Friction head loss, 200 g. p. m. through 800 feet

3-inch pipe (17.8 x 8) 142 feet

Elevation head 15 feet

Total head 226 feet

Experience has shown that the total head should

not exceed 275 feet and that pump capacities of

200 and 225 gallons per minute, per individual

pump, are most practical for nursery installations.

Several pumps, of course, may be needed in larger

nurseries.

The horsepower required to operate a pumping

unit is directly proportional to the total head and

6"UNDERGROUND MAIN

•2" PIPES ft RISERS

RISERS -53' O.e.

.iü

4

7

u 3?

1^1

s-^-^-^

FIGURE 9.—Diagrammatic layout of water system at Chittenden Nursery, Wellston, Mich.

Forest Nursery Practice in the Lake States 27
TABLE §>.—Losé' in head in 15-year-old ordinary iron pipe, caused by friction per 100 feet of pipe

Loss of head when pipe size was—

Discharge

(gallons

per minute) 'Ainch inch

1-

inch

1/4-

inch

1/2-

inch

2-

inch

214-

inch

3-

inch

4-

inch

5-

inch

6-

inch

•8-

inch

1

Feet

2. 1

7.4

15. 8

27.0

41. 0

147.0

Feet Feet Feet Feet Feet Feet Feet Feet Feet Feet Feet

2 1.9

4. 1

7. 0

10. 5

38. 0

80.0

136.0

3 1. 26

2. 14

3. 25

11.70

25. 00

42.00

64. 00

89.00

119. 00

152. 00

4 0.57

.84

3.05

6.50

11. 10

16.60

23. 50

31. 20

40.00

50. 00

60. 00

113. 00

0. 26

.40

1. 43

3. 00

5. 20

7.80

11.00

14. 70

18. 80

23. 20

28.40

53. 00

60. 00

102. 00

143. 00

5

10 0.50

1. 08

1. 82

2. 73

3. 84

5. 10

6. 60

8. 20

9. 90

18. 40

20.90

35. 80

50. 00

54. 00

76. 00

102. 00

129. 00

0. 17

. 36

. 61

.92

1. 29

1. 72

2. 20

2. 80

3. 32

6. 21

7. 10

12. 00

16. 80

18. 20

25.50

33. 80

43. 10

54. 30

66. 00

0. 07

. 15

. 25

.38

. 54

. 71

. 91

1. 15

1. 38

2. 57

3. 05

4. 96

7.00

7. 60

10. 50

14. 00

17. 80

22. 30

27. 20

31. 30

32. 50

38. 00

15

20

25

30

35

40 0. 22

. 28

. 34

.63

. 73

1. 22

1. 71

1. 86

2. 55

3. 44

4. 40

5.45

6. 72

7. 70

7.90

9. 30

12. 32

16. 00

19. 80

22.40

22. 96

24.00

45

50

70 0. 21

. 24

. 41

. 58

. 64

. 88

1. 18

1.48

1. 86

2. 24

2.60

2. 72

3. 14

4. 19

5.40

6.70

7. 22

7.42

8. 12

9.60

11.30

13. 20

15. 10

17. 20

75

100 0. 14

. 25

. 28

.32

. 48

. 62

. 74

. 92

1. 13

1. 15

1. 29

1. 75

2. 21

2. 65

2. 90

2.95

3. 30

3. 93

4. 70

5. 40

6. 20

7. 00

8.00

8. 95

10. 11

10. 80

12. 04

13. 30

14. 31

15.60

16. 69

18. 50

120

125

150

175

200

225

250 Ö. 22

270 .25

275 .27

300 . 32

350 . 42

400 . 54

450 . 68

470 .75

475 . 76

500 .82

550 .97

600 1. 14

650 1. 34

700 1. 54

750 1. 74

800 1. 97

850 2. 28

900 2. 46

950 2.-87

1 000 3.02

1 050 3. 21

1 100 3. 51

1 150 3. 84

1 200 4. 15

1 250 4. 45

1 500 6. 27

1 1

influences the economical operation of the unit.

Horsepower can be determined by the following

formula:

HP= G. P. M. X H

where HP=horsepower

3,950 X E

required; G. P. M. = gallons per minute to

be discharged; H = the total head in feet;

and E =efficiency of the pump.

For example: In determining the horsepower

required to operate a pump having a capacity of

225 gallons per minute, at a total head of 226 feet,

and a rated pump efficiency of 60 percent, the

formula becomes:

HP= 225 X 226

=21.45 or 22.

28

3,950X0.60"

Agriculture Handhooh 110^ Ü, S, Department of Agriculture
Irrigation Systems

It is important to develop an adequate and

efficient method of irrigation in most sections of

the Lake States because the sandy loam soil best

adapted for nursery production loses water rapidly.

To some extent, the general contour of the area

selected will dictate the method that can be used.

Ditch irrigation, a method commonly used, in

agriculture, is not satisfactory for Lake States

nurseries.

Overhead irrigation is most commonly used in

conifer nurseries. Because overhead systems are

efficient, simple to operate, and relatively cheap to

maintain, their higher installation cost usually can

be justified. Both portable and permanent types

are in common use. Where it is necessary to irrigate frequently to prevent drought, counteract

freezing, and control wind erosion, a permanent

system is recommended. Such a system, including water mains, overhead pipes, motors, pumps,

and automatic oscillators, cost about $500 to $600

per acre in 1951 ; labor and supervision for trenching water mains and installation cost about

another $150 per acre.

The portable system is equipped with quickaction couplings and connections so that it can be

taken apart easily and moved from one section of

the nursery to another. It is easier and cheaper

to install and requires only % to ji as many overhead lines as the permanent system. However,

the frequent tearing-down and re-erecting of the

system adds to maintenance costs and makes it as

expensive as the permanent type within a few

years.

The length of overhead lines and the number of

lines required for each compartment will be dictated by the length and width of the compartments. The maximum length of line that can be

used effectively is approximately 525 feet. Lines

longer than this require the use of large pipe,

which increases the weight of the fine and makes

repair more difficult. Where extremely long fines

are used as a unit, there usually is some lag in turning the relatively flexible pipe at the far end of

the line. This results in poor coverage of the

area. Although this difficulty is sometimes experienced in lines 525 feet long, the trouble can be

overcome by keeping the pipe in perfect alinement

and using a satisfactory type of pipe support.

The commonly used overhead irrigation system

consists of a series of parallel pipes usually spaced

52 to 53 feet apart and resting on pipe supports at

12-foot intervals on which turns an entire section

of coupled pipe 200 to 500 feet long.^ The pipe

supports have rollers to reduce friction. About

every 3 feet the overhead pipe has brass or other

rust-resistant nozzles that supply 7 to 8 gallons

per minute per 100 feet of line, or an inch of water

in 7 to 9 hours. An osciUator commonly turns the

Ö A spacing of 53.0 feet between pipelines is often used in

Forest Service nurseries, with a 1.0-foot path on either side

of the pipeline and a 1.22-foot path between each of the ten

4-foot-wide beds.

Forest Nursery Practice in the Lake States

408189°—57 3

pipe so that about 28 feet of soil on either side of

the pipeline is watered. The water, coming from

the mains and up through the riser, passes through

the oscillator. The pressure of the water makes

the whole length of overhead pipe oscillate through

90 to 110 degrees of arc, half of it on each side of

the pipeline.

A typical overhead irrigation pipeline includes

risers, oscillators, flush valves, and pipe supports

(fig. 10). Flush valves at the end of the line and

a bibb on every second riser are necessary. Bibbs

are useful for such tasks as packing stock and

watering ends of beds.

Roads and pipelines should be located with a

transit, and all underground parts and fittings

of the water system should be plotted accurately

on a map with exact distances, locations, and

dimensions. Such a map will be very useful in

draining or repairing the water system.

Overhead irrigation pipe and fittings can be

obtained from several irrigation equipment supply

companies, or it may be made up at the nursery.

If made at the nursery, the outlets in the pipe for

insertion of the small nozzles must be well alinedHowever, where a substantial amount of overhead

pipe is to be used, it ordinarily is cheaper and

more satisfactory to purchase the drilled pipe.

Wherever possible, standard pipe lengths should

be used because assembly is more rapid and

uniform, and repairs or replacements are easier.

To assure uniform distribution of water throughout the length of the overhead line, runs of various

lengths of different sizes of pipe are required. The

pipe sizes specified by most suppliers differ

slightly from the specifications set up by the

Forest Service. Forest Service specifications are

for slightly larger pipe to give good pressure at

the far end of the line (table 9). To provide for a

uniform assembly at the riser so as to facilitate

Sediment faucet

with

j hose connection

Quick action

coupling

¿X 4" G.I. nipple

2"x 1^-90° Reducing

elbow - G.

-Í—2" Galvanized pipe

Faucet with |- hose connection

2"x2"x J"G.I. tee ^--

T

¡1 :':■■'•: , „ .

/Ground line

-Underground main

FIGURE 10.—Overhead system of irrigation, showing

assembly.

29
interchanging of the turn motors which are used

for oscillating the lines, at least one length of

l^-inch pipe has been specified for each line.

TABLE 9.—Standard pipe required jor overhead

irrigation lines

l}á-inch pipe l}^-inch pipe 1-inch pipe

Total -fj

length

of line u o o;

(4-1 í^ U

0-Ö

o Qi k4

OXi

o o

(feet) o

ab s

r-4 C? O

00 s

.-H ¡y o

ce 3

a Oí

-tJ +j

b[. S =^ bû S '^ s "»

\

a

1-:!

§3 fi a s.sNum- Num- NumFeet ber Feet ber Feet ber

54 18

18

0

0

0

0

36

54

2

72^___ 3

90 18 0 0 72 4

108 18

18

18

18

18

18

0

0

0

0

0

0

0

0

0

0

0

0

90

108

126

144

162

180

5

126 6

144 7

162 8

180 9

198 10

216 18

18

18

18

18

36

36

36

36

2

2

2

2

0

18

36

54

72

72

90

108

126

0

1

2

3

4

4

5

6

7

198

198

198

198

198

198

198

198

198

234

252 _ __^

270

288

306

324

342 _,_ _

360____

378 36

54

54

54

54

72

90

108

126

2

3

3

3

3

4

5

6

7

144

144

162

180

198

198

198

198

198

8

8

9

10

11

11

11

11

11

198

198

198

198

198

198

198

198

198

396

414

432

450

468

486

504

522

Protection Against Freezing

Damage from freezing resulting in burst water

pipes and oscillators shoidd be avoided. Not only

should the oscillators on the overhead irrigation

linos be drained during the early spring and late

fall when temperatures frequently go below freezing, but the complete system also should be

drained when fieldwork is completed in the fall.

This usually is done by opening the gate valve

on the discharge side of the pump and removing

the suction pipe to allow the water to nm back

through the pump. Points in the line that cannot

be drained in this manner should be drained by

opening valves or by removing a plug at the

low points.

The pumps must also be drained by removing

the bottom plugs provided for this purpose. The

overhead lines are drained by turning them so

that the nozzles are pointing down. To insure

that the nursery is closed satisfactorily for the

winter, the nurseryman should have a list of the

various jobs to be done and check them carefully.

NURSERY BUILDINGS AND OTHER

INSTALLATIONS

The number and types of buildings required

for the efficient operation of the nursery will be

influenced by its size and permanency. Each

nursery will need certain structures for adequate

storage and protection of equipment (fig. 11).

Pumphouse.—Obviously, it is important that

the pumping equipment he protected adequately.

The building should be large enough to accommodate at least two imits and to provide sufficient

space in which to do light repair work on the

equipment. The pumphouse never should be used

for purposes that will expose the equipment to

damage.

Warehoiise.—The amount of warehouse space

required will depend to some extent upon the

amount of equipment to be stored. Som.e equipment, such as seedbed boards, bed screens, etc.,

can be stored out-of-doors, but storage room

should be provided for the mechanized equipment. Experience has shown that it is more

economical to build a large warehouse that acFinuRE 11.—Xote office in foreground, garage in center,

and field warehouse upper left. (Griffith State Nursery,

Wisconsin Rapids, Wis.)

30 Agriculture Handbook 110, Ü. S. Department of Agriculture
commodates a number of pieces of automotive

equipment and small tools than it is to build

several small buildings for special types of equipment.

For storing farm implements, a closed-shed type

of building has proved to be very satisfactory and

very economical. If a blacksmith shop is proposed,

fire protection dictates that it not be in the warehouse. Some nurseries find it advantageous to

have a repair shop in one end of the warehouse,

or in a separate building.

Office building.—The nurseryman should have

an office in which to keep his records and conduct

business with the public and nursery personnel.

In some instances it is expedient to locate the

office in one of the warehouses, but a separate

building has proved to be more satisfactory at

the Forest Service nurseries throughout the Lake

States. To handle such jobs as seed testing and

soil analyses, simple laboratory facilities are desirable in the administrative building. The office

should be convenient to the nursery work and

easily accessible to the general public.

Seed house.—A small supply of seed kept on

hand to meet production needs can be stored for

short periods in a room set off for this purpose in

one of the nursery buildings. If a large supply is

involved, the value of which is considerable, it is

desirable to have a separate building for seed

storage. The species commonly used in the Lake

States keep much better at low temperatures (33°

to 41° F.), so the seed-storage building should be

well insulated and equipped with a thermostatically controlled refrigeration unit. The size and

type of the unit will depend upon the size and

type of building and the outside temperatures

which normally exist. A competent refrigeration

engineer should be consulted about specifications

for the refrigeration unit.

Some nurserymen have found it convenient

and economical to build the seed-storage room in

the side of a hill. The temperatures to be maintained and the location of the seed-storage room

influence the type of construction and the kind of

insulation that should be used. Reinforced concrete usually is specified for underground walls,

roofs, and floors. In addition, several thicknesses

of cork board ordinarily are necessary on the

inner walls for adequate insulation, and a thick

coat of asphalt on the outer walls for moistureproofing. Ground cork and one or two thicknesses of cork board to reduce heat exchange

through the walls and ceiling are recommended

for seed-storage buildings built aboveground.

Specifications for such a building are available

from the Regional Forester, U. S. Forest Service,

Milwaukee 3, Wis.

Seed^extractory and cone-storage buildings. If

the demand for local seed is large or several nurseries are to be supplied, it is advantageous to

have an extractory. The Forest Service has two

types of extractories in the Lake States—^the convection and the internal-fan types (119). They

each require about the same kind of housing, but

the cost of equipment for the convection type is

much less than for the steam-heated, internalfan type.

The space needed for cone storage varies with

the species and the method of storing. It is important that the cone-storage sheds be located

near the extractory and connected to it by ramps

to facilitate the handling of the cones. However,

the buildings should be spaced far enough apart

to facilitate fire protection.

Compost pits.—It is desirable for each nursery

to have one or more pits in which to prepare compost. Materials stratified in a heap lose much of

their value as compost. A simple pit is a rectangular hole dug in the ground with the sides

^^cribbed up'' with poles or planks. However,

experience has proved that for long life the pit

should be built of reinforced concrete.

The floor of a concrete pit should have a slight

gradient to allow drainage toward one end where

the percolate, which contains a high concentration

of mineral fertilizers, can be recovered. Usually,

a cistern is provided as a catch basin for the runofï. At least one wall should be removable to

facilitate loading and unloading. Pits constructed

below the general level of the surrounding ground

are not so desirable as pits constructed on the

ground, because they are subject to flooding.

lEnough space should be left near the pit to permit

piling the material to be stratified and to operate

a shredding machine where necessary.

The size of the pit depends upon the annual

need for compost fertilizers. A pit 50 by 20 by 4K

feet, with a capacity of about 166 cubic yards, will

suffice for treating approximately 5 acres of seedbed at the rate of 1 cubic foot per 50 square feet

of bed, or 32.2 cubic yards per acre.

Puddled clay compost pits work reasonably well.

To make one, a shallow hole, some 15 by 20 feet,

is covered with several inches of fine clay that is

moistened and tamped or rolled with a sheep'sfoot roller. This creates a fairly impervious layer

that will retain the nutrient-laden liquids of the

compost heap.

Nursery dwelling.— Where the nurseryman must

be on 24-hour call, a modern dwelling at the nursery is desirable. However, nurserymen often

prefer to live in a neighboring town.

Cold storage building.—Nurseries that have a

large production program and a long shipping

season in the fall and spring require adequate

storage facilities. The initial cost, together with

subsequent maintenance, usually makes such plants

impractical for small nurseries.

Forest Service experience in the Lake States has

indicated that a storage capacity for 1 to 1^ naillion trees is required for nurseries having an annual

production of 5 to 8 million trees. This is based

on shipping stock during both the fall and spring.

A building 27K by 48 by 9 feet will suffice for this

Forest Nursery Practice in the Lake States 31
storage providing most of the stock is seedling age.

About 400 bundles of stock can be stored on pallets. The number of conifers per bundle for various classes of stock averages about as follows: 3.7

thousand for 2-0, 1.6 thousand for 3-0, 1.8 thousand for 2-1, and 0.6 thousand for 2-2.

The Forest Service has found that cold storage

buildings built partly underground have functioned as well as those entirely above ground.

The essentials of a satisfactory plant are an adequate refrigeration system, proper insulation, and

good construction. The walls should be moistureproofed to prevent rot in the wooden members as

a result of condensation on the walls and ceiling.

Adequate ventilation also is necessary while the

plant is standing idle.

Most hardwood species are not so sensitive to

rapid changes in weather conditions as are conifers. They can be stored satisfactorily on racks

in a building that has been properly insulated and

constructed for the control of temperature, humidity, and aeration (4^)-

Dressing room jor laborers.—'A clean room or

building in which employees can wash up and

change their clothes helps to maintain high morale

and good production. The type of a building to

provide will depend upon local conditions and

regulations governing such facilities.

Landscaping.—^It is desirable to maintain the

natural appearance of the nursery. Landscape

planting should be simple and limited to screening from view areas that would otherwise detract

from the appearance of the nursery. Areas of

lawn should be held to a minimum. Native species that grow on areas not suitable for nursery

production should be protected and encouraged.

However, undesirable species or plants that are

hosts for disease or insect pests should be removed.

Parking accommodations should be provided for

visitors where their cars will not be damaged by

traffic within the nursery nor interfere with nursery operations.

Fire protection.—^To minimize the danger of fire

loss, the nurseryman should arrange with the local

fire department to answer emergency calls. Facilities for fighting fires also should be included in

the development plan.

Cash investment in a nursery.—^The investment

in a forest nursery, including buildings, overhead

irrigation, and equipment, is substantial. The

cost of several typical Lake States nurseries of 20

to 50 acres, developed before 1937, ranged from

$70,560 to $171,500 (23).

NURSERY PERSONNEL

Much of the work in a forest tree nursery is

similar to farming or gardening, but the crop is

distinctly different. Therefore, it is important

that the nursery superintendent have some technical training in forestry or horticulture. He must

(1) have some knowledge of agronomy and the

origin and composition of soils; (2) be able to

recognize insect and disease attacks and take

prompt remedial action; (3) be capable of training

personnel, organizing and supervising crews, and

planning the various nursery projects; and (4) be

able to design and construct simple, efficient pieces

of equipment to meet special needs. A capable

assistant nurseryman is also desirable.

A few year-round key personnel are needed, and

most nurseries require some seasonal supervisory

personnel who are capable of doing a variety of

jobs and of accepting responsibility. A backlog

of work for the year-round key personnel can be

provided by postponing until fall or winter such

tasks as overhauling equipment, constructing new

equipment, building up of stocks of materials, and

extracting seed.

The importance of a local labor supply has

already been stressed. Labor recruited from distant sources usually requires living quarters and

mess at the nursery, which imposes extra work

upon the nurseryman. Also, experience has shown

that local labor is more satisfactory than transient

labor, both because local residents usually are interested in doing a better job and because there is

less of a labor turnover.

Where local labor is in short supply, it is highly

desirable for the nurseryman to develop methods

of work that will permit him to employ both men

and women. Operations that require nimble fingers usually can be performed better by women

than men. Women also are very effective on

other light work where physical endurance or

strength is not required.

32 Agriculture Handbook 110.^ JJ. S. Department of Agriculture
MACHINERY, TOOLS, AND SPECIALIZED EQUIPMENT

Mechanization of most phases of nursery operations has resulted in a marked reduction in manpower requirements. Studies in other regions

have shown a reduction up to 97 percent for seeding (92) and of 76 percent for all operations (4^).

Comparable savings doubtless have been made in

Lake States nurseries through labor-saving devices.

Many of the standard pieces of farm equipment,

such as plows, disks, and harrows, can be used

effectively in the nursery. However, special

types, including seeders, transplanters, cultivators,

root pruners, and lifters, must be constructed

locally or modified from commercial models. For

standard equipment some modification is usually

necessary because of differences in soil types.

It is important that all equipment, including

small tools, be kept in good condition. This can

be accomplished only by current inspection of each

piece and replacement of wornout or broken parts.

All equipment and machinery should be stored

under cover during the winter or other periods

when not in use.

Equipment placed in storage for long periods

should be thoroughly cleaned and oiled beforehand. In addition, a thin coat of heavy oil should

be applied to equipment surfaces that come in

contact with the soil; for example, the plow point,

moldboard and landside on a plow, and the disks

on a disk harrow.

TRACTION EQUIPMENT

Tractors and other motorized equipment have

almost completely replaced horses in Lake States

nurseries. In choosing a tractor, the nurseryman

should consider the jobs and the character of the

soil on which the tractor primarily will be used.

The job of pulling the tree lifter through the beds

at a depth of 8 to 10 inches probably will be the

heaviest job that the tractor will have. Consequently, where only one tractor is available it

should be of a size adequate for that job. If the

nursery is large enough to justify having 2 tractors,

it is best to have 1 large tractor and 1 small tractor.

The wheel-type tractor is preferred to the

crawler-type for general nursery work. This is

because it is more maneuverable and less expensive

to operate. One with 33- to 35-drawbar horsepower is satisfactory for the heavy work, such as

plowing, disking, or pulling the tree lifter; for the

light work, such as drawing a utility trailer,

mechanical seeder, or fertilizer spreader, 15- to

18-drawbar horsepower is adequate.

GROUND PREPARATION

EQUIPMENT

A sturdily constructed plow and disk harrow

usually are required for breaking new ground or

plowing old fields with brush or a heavy sod.

Following initial ground preparation, a 16-inch,

2-bottom plow, or a 26-inch disk plow with disks

10 to 12 inches apart, is a very effective tool for

turning under soil-improvement crops and doing

general tillage work. Disk plows and chisels are

favored by some as a safeguard against formation

of a plow sole.

Where dead furrows are a hindrance in maintaining a level seedbed, a two-way plow is useful.

It is fitted with both a right- and left-hand bottom

and, when plowing back and forth across the

field, it throws all of the furrows one way.

A spike-tooth harrow aids materially in breaking clods and can be used effectively for leveling

the ground. Various depths of penetration can

be obtained by adjusting the angle of the spikes.

The width of cut varies with the size of the single

section and the number of sections hooked together and pulled abreast as a unit.

The spring-tooth harrow is useful for shallow

cultivation in the final preparation of seedbeds.

It can also be used to dig out quackgrass and other

noxious weeds, and to rake debris to the surface.

Depth of penetration is governed by changing

the pressure on the teeth. This tool is made in

sections and the width of cut is governed by the

number of sections assembled as a unit.

After being cleared or cultivated, the land

usually can be leveled with a ^ afloat^' drawn across

the field at right angles to the direction traveled

earlier by the harrow. The nurseryman can

build a ^'float" by lapping four or five 10- or 12-

inch planks, 8 to 10 feet long, and securely fastening them together with bolts or spikes; they

should be braced across the top to give the unit

rigidity. Short lengths of chain fastened 24 to

30 inches from the ends of the front plank will

serve as a hitch. Extra weight or pressure can

be obtained by using stones or sandbags as ballast.

The rotary tiller is a new tool that in effect

plows, disks, and harrows in one operation.

It has proved very satisfactory for preparing

ground and working compost and green cover

crops into the soil. Also, this tiller is ideal for

preparing a very loose, friable seedbed in light

sandy soils. However, it has the disadvantage

of destroying crumb structure and so rendering

the soil more subject to wind erosion. Tests in

Forest Nursery Practice in the Lake States 33
Forest Service nurseries indicate that the rotary

tiller is effective in destroying some insects, such

as white grubs, which infest the soil and feed on

the roots of seedlings.

This tool has a high-speed rotor equipped with

tines that pulverize and thoroughly mix the soil.

The very small models are compact, self-propelled

units, and the larger ones, which vary from 3 to

6 feet in width, operate from a power takeoíí or

are powered by an engine mounted on the forward

part of the machine (fig. 12). The power is

F-464650,365838

FIGURE 12.—A, A self-propelled rotary tiller. B, A 4-foot

rotary tiller operated by power takeoff from a tractor.

transmitted by a double universal joint and spiral

bevel gear to the rotor assembly. A hood mounted

over the rotor confines the pulverized soil to the

area being tilled. Depth of tillage is accurately

controlled by adjustments provided by the rotor

lifting bar.

SEEDING EQUIPMENT

It is important that uniform stands of seedlings

or cover crops be obtained. Although broadcast

seeding by hand can be done quite successfully

by trained and experienced help, it cannot be

done with the uniformity and efficiency that is

obtainable with mechanical seeders.

The ordinary farm grain drill is used in the

Lake States nurseries to advantage for seeding

cover and green manure crops. These machines

are adaptable to sowing grain, grass, and legume

seeds, and can be adjusted to sow at desired

rates per acre. Since slightly better results can

be obtained if the seed is firmly packed, drills

equipped with packing attachments are recommended for use in sandy soils. Experience has

shown that an 8-foot drill is better adapted to

nursery requirements than either a wider or

narrower drill. Grain drills can be obtained with

attachments for fertilizing the crop at time of

drilhng the seed.

Because of the limited demand for equipment

that will handle tree seed, it usually is necessary

for nurserymen to design and construct their

own seeders. Seed drills used in the Forest

Service nurseries in the Lake States for conifer

seed (fig. 13) are composed of standard parts

available on various types of commercial equipment. The grain cups and grain tubes that convey the seed from the hopper to the seeding assembly are from a commercial farm seed drill.

34

F-464643, 464646

FIGURE 13.—A, Standard 4-foot-wide, 10-row conifer

seed drill. Seeding rate can be adjusted by changing

the size of the sprocket gears on the right side of the

machine. The machine is pulled by two men or by a

bed-straddling tractor. B, A 7-röw seed drill with

flanged roller that controls depth of seeding.

Agriculture Handbook 110, U. S. Department of Agriculture
The seeding assembly parts, including an adjustable furrow-opening shoe, a furrow coverer, and

a packing wheel mounted on a frame, are from

commercial hand seeders.

Although the basic tree seeder will sow 10

drills lengthwise of the seedbed in one operation,

fewer drills can be sown by closing off as many

grain cups as desired and spacing the seeding

assembly accordingly. The spacing between drills

where 10 drills are made per 48-inch bed is 4.6

inches. Broadcast seeding can be done with this

seeder by removing the seeding assembly and

substituting a splashboard on which the seed

strikes as it falls to the ground.

The basic seeder is designed to sow seeds of

various conifers at different densities as required.

For the larger seed, rate of sowing is regulated by

a change of gear ratios and size of the grain cup

opening by an adjustment of the hopper bottom;

for the very fine seed, grain cup reducers are

inserted.

Some nurseries use lawn seeders for broadcast

seeding of beds, subsequently covering the seed

with sand by means of a mechanical sander or,

in case of small lots, by hand. These seeders

range in width from 18 to 48 niches. The narrow

model, in two trips on each bed, seeds slightly

less than half of the bed and leaves an unseeded

strip down the middle.

A mechanical drill seeder can be used for a few

of the broadleaf species, such as mountain ash,

yellow birch, and black locust. Aiaple and ash

seeds whose wings are difficult to remove, and

acorns and nuts, can best be seeded by hand in

small, open furrows. Several simple tools are

available for makhig these furrows (fig. 14).

FIGURE 14.—A 5-ro\v furrow opener for hand-seeding

hardwood species.

FERTILIZING EQUIPMENT

It is important that fertilizers be distributed as

evenly as possible in order to produce uniform

crops of seedlings. Several types of manure

spreaders are available for distributing manures

and composts. These machines vary in capacity

but all are equipped with devices to regulate the

Forest Nursery Practice in the Lake States

rate of application. Machines that shred or

break up clods are preferred because they spread

fertilizer more evenly than other types of machines.

There are attachments, to be used on grain drills,

for applying mineral fertilizers. These devices are

satisfactory when the fertilizers are sufficiently

uniform in texture to flow evenly. If relatively

heavy applications of mineral fertilizer are

required, a spreader designed for lime or other fine

materials can be used efi^ectively. This equipment, mounted on wheels, consists of a hopper

with adjustable, slotted openings in the bottom.

An agitator mounted within the hopper and slightly above the openings maintains an oven flow of

fertilizer, and a baffle board, mounted at an angle

beneath the openings, disperses the fertilizer uniformly. Fertilizer spreaders of this type can be

obtained in widths of 2 to 10 feet with capacities

of 1 to 18 bushels.

TRANSPLANTING EQUIPMENT

Hand transplanting of nursery stock has almost

disappeared in the larger Lake States nurseries

because of the availability of agricultural equipment that can be easily modified. For small

operations, where the investment in a transplanting machine cannot be justified, hand methods and

equipment can be used very effectively (fig. 15).

The mechanical transplanter used in Lake States

nurseries is a modification of the commercial

transplanter for celery, tomato, and cabbage

plants (fig. 16). This self-propelled machine is

equipped with a self-steering device. The power

unit is a small, air-cooled, gasoline engine that can

be regulated for various speeds. Power is transmitted to the clutch shaft by a V-belt drive and

thence, by a series of sprockets and drive chains,

to the rear driving wheels. The planting devices

include revolving disks with plant pockets or

holders, a 12-incli rolling coulter, a furrow-opening

shoe, 2 packing wheels, a plant-box holder, and an

operator's seat.

The operation of the planter is relatively simple.

As the unit travels over the ground at 11 to 14

feet per minute, the coulter and shoe open a

trench 2 inches wide and 6 inches deep. The

seedlings are placed in the pockets of the revolving

plant-holding disks, with their tops toward the

center of the disks. When they reach an upright

position in the trench, they are released and

packed firmly in the ground by the packing wheels.

The 2 planting units with which the machine is

equipped arc demountable and can be adjusted to

7 positions on the drawbar to vary spacing between

rows. The machines used in Forest Service

nurseries in the Lake States will plant in two

adjacent beds at one time; this provides an even

draft and facilitates guiding the machine to

produce evenly spaced rows. Machines that

transplant a full bed of 5 or 6 rows, evenly spaced,

simultaneously, are in operation at 2 nurseries in

Ohio and 1 in Wisconsin.

35
F-473980, 409I4S

FIGURE 15.—A, A hand trencher for transplanting operations. Blade, 2 pieces of }4-inch steel 14.5 by 6.5 inches

in size, 2-inch spread at top; handle, 32.5 inches long;

handle grip, 1-inch iron pipe 13.5 inches long; braces,

^^-inch solid iron bars. B, A tractor-drawn trencher.

WEEDING AND CULTIVATING

EQUIPMENT

Although much of the weeding in conifer nurserybeds now is done with oil sprays, there still is a

need for meclianical tools for removing weeds resistant to sprays. Because of the close spacing

used in the seedbeds and the susceptibility of the

small seedlings to mechanical injury, few of the

standard mechanical garden tools can be used.

Some, however, such as the rotary type of hoe and

cultivator, and wheel-type cultivators with adjustable attachments, can be used for cultivating

conifer transplant beds and hardwood seedbeds.

Lake States nurserymen have developed a

rotary-type mechanical weeder and mulcher. This

tool has proved very effective in weeding seedbeds

during the very early period of germination when

hand-weeding methods and applications of herbicides would damage the yotmg seedlings. It consists of a battery of small rotors equipped with

metal spines that stir and mulch the ground as

they rotate. The rotors are powered by sprockets

and chains from a main drive shaft that receives

its power from a small gasoline engine mounted

forward on the frame of the machine. The frame

on which the rotors and engine are mounted is

supported on four small pneumatic-tired wheels.

Although the machine is not self-propelled, the

action of the rotors gives it a forward motion. The

additional power required to draw the machine

over the beds is furnished by two men.

Another very effective tractor-drawn mechanical

weeder was devised by the Tennessee Valley Authority and adopted by the Wisconsin ConservaFiGUBE 16.—Transplanting

machine used in the Lake

States.

36 Agriculture liandhook 110, U. S. Department of Agriculture
tioii Department (179). This tool (fig. 17) consists of a standard Planet Jr. pulverizer attachment

No. 7730X equipped with shields; each cultivator

imit is mounted independently on a rubber-tired

carrier unit. The entire battery of cultivators can

be moved to either side by wheel or lever while the

luiit is in forward motion. Thus, it is possible to

follow slight unevenTiess in rows and to compensate

for the tendency of the cultivator to creep sideways on gentle slopes. The cultivator rotors get

their chopping-knife action by forward motion of

the entire cultivator unit. This device has been

successfully used in 10-row, 4-foot-wide beds where

space between rows is about 4.5 inches.

Garden hoes, rakes that have been cut down,

and stirrup hand hoes are effective for weeding and

cultivating close to the rows of seedlings where

mechanical methods of weeding and cultivation

are impractical.

LIFTERS AND ROOT PRUNERS

Two types of tree lifters, the single-row U-blade

type and the multiple-row sled type, are effective

for removing seedlings from the beds without injury to the plant root systems. Originally lifters

were horse-drawn, but various schemes for mounting them have been worked out successfully (fig.

18). Because the U-blade type is light in weiglit,

it is easily mounted directly on a tractor. The

sled-type digger (fig. 19) can be pulled by a tractor

or it can be drawn through the beds by means of

a winch and cable. The latter method affords

better control of the tool and an additional advantage is gained through making the tractor

easily and quickly available for other work. This

tool docs a better job of stirring up the soil and

loosening the trees if short pieces of flat steel are

attached to the blade.

The separate imit sled-type lifter can bo

mounted on wheels or supported on an easily

removable skid-shoe for transportation Irom one

point to another. The latter scheme has proved

more convenient. Another type of carrier consists

of a unit of channel iron on the back of the tractor

on which the lifter can be suspended.

Where wide spacing is used in propagating hardwood seedlings, the single-row, U-blade lifter has

proved more satisfactory than the multiple-row

tree lifter. Since the crowns of most hardwood

species are larger than those of conifers and

slightly longer roots are required, the digging

tool should provide for greater crown clearance

and greater cutting depth.

The tools used for lifting are not entirely satisfactory for root pruning seedlings in place, because

a thin, sharp blade is required. A tool tliat has

been used in the Lake States nurseries with some

success is a U-shaped blade mounted on a sledtype frame similar to one on which the tree lifter

blade is mounted. The horizontal section of the

blade is made of higli-grade steel (bandsaw steel)

and is bolted to the vertical sections with cap

F-476.J83, 4763S4

FIGURE 17.—Rotary weeders for seedbeds sown in drills.

A, Overall view; B, closeup of rotary hoe units.

screws. The blade is 52.4 inches long, 1.75 inches

wide, and 0.08 inch thick. Two holes are drilled

0.75 inch from each end of the blade into which

the cap screws fit. It is kept taut by a brace

between the upright sections about one-third of

the distance from the top of the vertical sections,

and by means of a rod equipped with a turnbuckle

that connects the side pieces.

SPRAYERS

Several types and models of spraying equipment

for herbicides and insecticides are available commercially. Some nurserymen in the Lake States

mount a small pressure pump and a spray boom

directly on a tractor and carry the herbicide in a

container on the roar of the machine. Forest

Service nurseries use a commercial skid-type

sprayer. This compact and efficient unit is carried on a light tractor trailer wide enough to

straddle the beds. Although it requires loading

and unloading from the trailer and the transfer

of the herbicide from the shipping container to

the tank on the sprayer, it eliminates much of the

strenuous work and hazards connected with carrying herbicides on a tractor.

Forest Nursery Practice in the Lake States
F-153298. 464642

FinuRE 18.—A, A horsedrawn tree lifter in operation. B, A sied type

lifter.

The skid-type sprayer lias an adjustable boom

that permits treating 3 beds in 1 operation. The

boom is made in three sections, each of which can

be shut off as desired. Each section is equipped

with three mist-spray nozzles that give a uniform

coverage, and the rate of application as well as

pressure can be controlled accurately.

This sprayer can also be used for treating insect

infestations where contact sprays and liquid

stomach poisons are recommended, and for spraying noncorrosive fungicides. It can be used for

other spray work by removing the horizontal

boom and fitting the unit with the proper type of

spraying attachments.

Commercial hand sprayers are not recommended

because they are undependable for uniform coverage and are relatively inefficient when large acreages and frequent sprayings are involved.

Special equipment is required for handling

sulfuric acid and corrosive fungicides. Although

a wooden barrel equipped with a lead-pipe boom

is an inexpensive piece of equipment for applying

acids, a lead-lined wooden tank with a lead-pipe

boom is more satisfactory. The size of the tank

required will depend to some extent upon the

amount of seedbed area to be treated annually.

A wooden tank with an approximate 200-gallon

capacity, mounted on a chassis equipped with a

tractor hitch, is a safe and dependable piece of

equipment for applying chemical solutions. The

tank, filled from the top through an opening 18

by 18 inches, is fitted with a tight lid to prevent

the fungicide from splashing when the sprayer is

being used. The discharge pipe is a l^-inch

galvanized pipe and the sprinkler pipe is a 1- by

49-inch lead pipe. The latter has }^-inch outlets

drilled 1 inch apart to permit even and uniform

distribution of the fungicide. A l)^-inch gate

valve is used as a shutoft' and to regulate the flow.

The unit is also equipped with a platform on

which the operator may ride.

SEEDBED BOARDS

Seedbed boards serve as a barrier to the action

of sand across the surface of the beds during the

period of germination and early seedling stages.

They also serve as frame supports for seedbed

screens. The seedbed boards in Forest Service

nurseries are 1- by 4-inch 12-foot boards, and strap

iron stakes are used to hold them in place (fig. 20).

38 Agriculture Handhook 110, U. S. Department of Agricultuj
^"APA'^"/>¿?/fS

T o

2'

Z^rz^/z ^/^ cc/rr/A/^ JRí/A/A/S/?

^6'^

^^^^

Shakers fo be riveted on for digger and

removed wtien used as a roof pruner.

^''So//-s

FIGURE 19.—Details of construction of a sled-type tree lifter. This lifter can be used for root pruning when the

nine soil breakers are removed.

Although pine lumber is sometimes used for

seedbed boards, white-cedar gives longer service.

Rough material is favored over surfaced material

because it gives added strength and greater rigidForest Nursery Practice in tiie Laite States

ity. If pine lumber is used, preservative treatment will increase its service life. Boards treated

with creosote in the early thirties (74) have given

20 years of service and are still usable. Because

39
TYPE I TYPE n

-2"-

> '"i

W ^i"

VJ;..rap

_L

'i

ib

FiGXJRE 20.—Iron bedboard stakes: Type I (U-type) is

used where ends of boards meet; type II (clip type) is

used at midpoints. Some nurseries use type II exclusively.

creosote and pentachlorophenol are toxic to small

seedlings, treated seedbed boards should be

stacked with spacers and not used until at least

the second season following treatment.

SEEDBED SCREENS

Most forest nurseries in the Lake States use

hardware cloth screens to protect the seedbeds

from birds and rodents. The hardware cloth, 48

inches wide, is best handled in 33- to 50-foot-long

sections rolled directly on the 1- by 4-inch bedboards. The rolls are overlapped about 6 inches

and held with a turn of wire. For placing and

removing the screen, a bed-straddling, tractordrawn trailer is a useful labor-saving device. To

help hold the screen in place and to prevent its

becoming bent out of shape, 1- by 2- by 49-inch

slats are stapled at 3- or 4-foot intervals across the

width of the cloth. The screens are tacked to the

bedboards, slat side up, so that they will lie flat.

A few nurseries use the 4- by 12-foot Pettis

seedbed frame with screened sides that support a

covering screen, but their bulk in storage and cost

of maintenance, and the time-consuming effort in

installation and removal, make them somewhat

more expensive and less desirable than longer

screens used in roll form. Some nurseries use lath

racks with attached legs.

HANDTOOLS

A nursery, of course, needs the usual complement of handtools such as rakes, spades, hoes, and

rotary hand weeders. The latter are especially

useful in keeping paths clean (fig. 21).

FIGURE 21.—A 10-inch-wide rotary hand weeder suitable

for weeding paths and rows of broadleaves or transplants at 12- to 14-inch spacing in sandy nursery soils.

The blade at the lower left cuts weed roots horizontally

and the angled blades on the revolving reel pulverize

the soil.

40 Agriculture Ilandhook 110, U. S. Department of Agriculture
SOIL MANAGEMENT

One of the important steps in successful nursery

practice is proper managenaent of the soil. Its

maintenance in a condition of proper fertility,

acidity, tilth, and drainage will pay big dividends.

In the Lake States, nurseries cut out of existing

forest land produce excellent stock for about 4

years. Thereafter the size and quality of stock

decline and it is necessary to add compost or peat

and commercial fertilizer. Even after treatment,

however, the quality of stock produced is seldom

as good as that of the first crop or two. Cultivated

areas, old fields, or former pastures usually must

be fertilized heavily from the very start.

Continuous nursery production creates a considerable drain on the soil nutrients because of the

closeness at which the plants are grown and the

fact that the entire plant growth is later removed

from the soil. Based on chemical analyses of red

pine nursery stock of several age classes, Lunt

(86) calculated the annual nutrient intake per acre

in term.s of nitrogen (N), phosphorus (as P2O5),

and potassium (as K2O) as follows: 41, 14, and 18

pounds for 1-0 stock; 154, 32, and 59 pounds for

2-0 stock; and 84, 23, and 41 pounds for 2-1 stock.

He concluded that 10 parts of total N, 4 parts of

P2O5, and 5 parts K2O would provide a good balance

of soil nutrients.

An analysis of 27 samples of 2-0 jack pine from

the Hayward Nursery in Wisconsin showed the

following percents of nutrients in the plants, including needles, stem, and roots: average nitrogen,

1.65—orange from 1.48 to 1.76; average phosphorus

(as P2O5), 0.245—range from 0.213 to 0.275; and

average potassium (as K2O), 0.727—range 0.572

to 0.968. The calculated per-acre drain of nutrients by removal of the crop of 2-0 jack pine,

weighing 3,740 pounds per acre (ovendry), was

61.7 pounds nitrogen, 9.2 pounds phosphorus (as

P2O5), and 27.2 pounds potassium (as K2O).

The amount of nutrients actually supplied in

fertilizer must greatly exceed that found in tissue

analysis, because of loss by leaching and capacity

of certain soils to fix, in unavailable form, a substantial amount of nutrients, especially phosphorus. It is not uncommon for some nursery

soils to fix several hundred pounds per acre of 20-

percent superphosphate or its equivalent. Therefore, actual observation of trends in stock developm.ent in nurseries and of response to fertilizers

affords a more direct and reliable approach to the

problem of soil management than does tissue

analysis.

The chief elements that need to be supplied to

Lake States nursery soils are nitrogen, phosphorus,

potassium, magnesium, and occasionally calcium.

The latter is needed particularly for broadleaf

Forest Nursery Practice in the Lake States

species and occasionally for conifers on strongly

acid soils. A general sulfur deficiency is suspected

in a considerable area of northern Minnesota, including parts of the Chippewa and Superior

National Forests. If there is a sulfur deficiency

in nurseries situated there, it probably can be

corrected by the standard treatment of one-eighth

fluid ounce of sulfuric acid per square foot.

FERTILITY OF NURSERY SOILS

Minimum levels oj soil fertility.—Soil tests will

indicate the approximate amount of fertilizers

needed, if any, to correct soil deficiencies. Quick

chemical tests can be made on-the-ground with

special kits (1^5,168) y or soil samples can be taken

for testing by private or public testing agencies.

Standards of fertility satisfactory for growth of

the more common Lake States tree species were

determined by S. A. Wilde (190) by analyses of

surface soils from typically well-developed natural

stands (table 10). In actual nursery practice

these standards are quite satisfactory, except that

excellent 2-2 red pine, white pine, or white spruce

transplants can be produced by reducing the

indicated levels of total nitrogen by one-fourth.

Areas that test below these minimums and are

devoted to the production of seedlings or 1-year

transplants should be fertilized.^^

When soil analyses show that nutrient levels

already are adequate, the addition of more fertilizer may result in top-heavy, succulent plants

that do not survive well in fall plantings (fig. 22).

Such overfertilization is most likely to occur in

2-0 jack pine, and to some extent in 3-0 red pine

and 3-0 white pine.

Acidity.—Under most nursery conditions in the

Lake States, adjustment of acidity is not a problem. A problem may exist, however, if the soil is

highly acid or definitely alkaline, because these

extremes in pH result in malnutrition of nursery

seedlings. In extremely acid soils (pH 4.0 to 4.5)

there is a sharp reduction in the availability of

potassium, phosphorus, calcium, and magnesium

(174)' Also, soils of high acidity have a low

capacity to retain nutrients such as potassium and

ammonia nitrogen, and the danger of loss by

leaching is correspondingly higher (181). Where

soils are rather limy (pH 7.7 to 8.5), chlorosis

10 A map record of soil fertilizer applications, cover crops

used, the dates they were applied or sown and the arhounts

per unit of area, chemical treatments for white grub control, weed reduction, and similar practices is worthwhile

(106). It gives the nurseryman a quickly grasped picture

of the status of treatment without his laboriously sifting

through a mass of written records. The base map should

show the area of each unit and the length of beds.

41
TABLE 10.—Standards of nursery soilfertility for several representative Lake States tree species

Species

Reaction,

pH

Base exchange

capacity

per

100 gm.

soil

Total

nitrogen

Available per acre

NitrogenPhosphorus

(P2O5)

Potassium

(K2O)

Replaceable per

100 gm. soil

Calcium

Magnesium

Jack pine

Red pine

Scotch pine ^

White pine

White spruce

Norway spruce 2.

Yellow birch

Sugar maple

Basswood

White ash

o. e

5. 4

5. 4

5. 3

5. 8

5. 8

6. 2

Milliequivalents

5.0

8. 0

8. 0

10, 0

15. 0

15. 0

12.0

14. 0

14. 0

16. 0

Percent

0. 10

12

12

14

25

25

16

20

20

22

Pounds

20

30

30

35

45

45

35

45

45

55

Pounds

40

50

50

80

100

100

60

150

150

185

Pounds

100

150

150

200

250

250

175

275

275

300

Milliequivalents

2. 0

3. 0

3. 0

5. 0

6. 0

6. 0

5.0

8. 5

8. 5

11. 0

Milliequivalents

0. 5

1. 0

1. 0

1. 5

2. 0

2. 0

1.5

2. 5

2. 5

3. 0

' Reprinted by courtesy of Chronica Botánica from Forest Soils and Forest Growth, by S. A. Wilde, 1946.

2 Standards extended on the basis of practical nursery experience.

develops because of tlie limited availability of elements such as iron, manganese, boron, zinc, and

copper. Phosphorus also is less available, dampi-iâit^

«, m 7 r

l\

Wm/I^^ Jwxi1^ 1 1 \^ '^ A V 'm^ 1

1 ^^KJ'/^ ^

É..-.

FIGURE 22.—The 2 top-heavy, poorly balanced 2-0 jack

pines at the left were grown on a fertilized plot, the 2

at the right, on an imfertilized plot. The trees from

the fertilized plot would not survive as well in fall planting or after a serious drought following spring planting.

This demonstrates the value of determining the need

for fertilizer applications through soil tests.

ing-ofï and root rot diseases are accentuated, and

mycorrhizal development is poor.

Old well-established nurseries in the forested

northern parts of Wisconsin, Michigan, and Minnesota have a tendency toward somewhat too low

a pH. Repeated use of rather acid peats, or of a

dilute sulfuric acid or other acidifying materials,

has in many instances lowered the average

original level of pH from about 5.5 to as low as 4.0

in the most acid spots in the nursery. For

example, in a northern Wisconsin nursery the

original pH of the soil was 5.3 to 5.5, but in 18

years soil treatments with dilute sulfuric acid and

acid peat (pH 4.4 or lower) had lowered it to about

4.0 in some spots. Jack pines and red pines grew

poorly and the outer third of their needles became

bright yellow orange, a symptom of magnesium

deficiency {11, 193). Dolomitic limestone apphed

at 1,000 to 1,500 pounds per acre brought the pH

at the 0- to 4-inch depth from 4.1 up to 5.0 or more,

improved the needle color, and increased growth

(table 11). When the pH values given in table 11

are plotted graphically over the amounts of limestone applied, the result is a curve of almost perfect

correlation.

In another test the application of 1,000 pounds

of ground limestone to a light sandy soil with a

silt-plus-clay content of around 12 to 14 percent

increased the pH from 4.0 to about 4.9 (table 12).

However, ground limestone should not be applied

just before conifer seed are sown because it may

result in heavy damping-off. Where both soil

tests and foliage symptoms indicate excessive

acidity, limestone should be added to the compost

that is applied to a cover crop, to transplant areas,

or to localized areas of off-color seedlings beyond

the succulent stage.

Applications of dolomitic limestone may be

followed by reduced growth of acidophilic conifers

unless soluble nitrogen is added {190).

42 Agriculture Handiook 110. V. S. Department of Agriculture
TABLE 11.—Effect of application of ground limestone

on iirst-yearjack pine seedbeds in areas of excessive

acidity ^

Trees with yellow foliage Total

Ground because of excessive ini- green Soil

lime- tial acidity weight reaction

stone of 100

trees as

Sept. 28,

per acre 1948

(pounds) July 27, Oct. 6, Oct. 5, 1-0

1948 1948 1949 stock

Percent Percent Percent Ounces pH

0 32. 6 56. 2 27. 5 8. 00 4. 11

500 39.8 29. 0 13. 7 9. 50 4. 60

1,000 42. 4 19. 3 12.5 10. 10 5. 03

1,500 42. 9 17. 4 12. 5 11. 20 5.25

2,000 34. 4 12. 6 11. 2 8.85 5. 51

1 Treated with limestone on July 28, Î948.

TABLE 12.—Changes in pH in the surface 4 inches

of a sandy nursery soil 2 months after treatment

with ground limestone

Initial pH

Changes in pH value when application level of limestone was—

500

pounds

1,000

pounds

1,500

pounds

2,000

pounds

4.0

4.5 __ __

+ 0. 5

+ .4

+ .3

+ 0. 9

+.7

+.5

+ 1.2

+ .9

+. 6

+ L3

+ 1. 0

5.0 1 +. 7

^ Value estimated.

In the prairie part of Minnesota, and in southern

Wisconsin and Michigan, the soil pH may become

alkaline from irrigation water heavily laden with

carbonates. Also, the use of a sand cover that is

alkaline in reaction can create a problem. These

prairie soils may shift in pH from 6.0 to 7.5 in 4

to 5 years from applications of slightly alkaline

water. Their pH must be lowered to 5.5 or 6.0 if

reasonably satisfactory growth is to be attained.

Species that are especially sensitive to soil alkalinity in the seedling stage include jack pine, red

pine, Scotch pine, blue spruce, western white

spruce, white spruce, and, to a lesser extent, ponderosa pine. Junipers have done rather well in

soils that are neutral or slightly alkaline up to pH

7.5 to 7.6.

The alkalinity of conifer seedbed soils cannot be

corrected satisfactorily by the usual fertilization

practices. The soil must be acidified. Such treatment will greatly enhance the efi^ects of fertilizers

applied later, and will improve the rate of spread

of beneficial mycorrhiza.

A sample of soil can be easily tested for alkalinity with a few drops of dilute (10 percent) hydrochloric or sulfuric acid. If it effervesces readily,

the pH will be above 7.0. In an actual case, a

nursery soil in North Dakota, similar to what

Forest Nursery Practice in the Lake States

might be encountered in western Minnesota, had

built up from its normal pH of 6.8 to 7.5 to 7.8

in 4 years. Damping-off increased and stock of

jack pine, Scotch pine, and spruces, and to a lesser

extent ponderosa pine, was very poor in vigor,

needle length, bud development, weight, and

height. Phosphorus assimilation was very poor.

Applications of a 2-percent solution of sulfuric

acid, using about 1 pint of water per square foot

of bed, resulted in doubling the weight of spruce

stock. In some instances it doubled or trebled the

number of usable plants where one-fourth ounce

of concentrated acid per square foot was used,

diluted with water. Higher dosages may cause

damage when the beds dry out unless they are

watered very heavily following application.

Nurserymen confronted with alkalinity problems may find the following tabulation useful. It

indicates the probable shift in pH of moderately

alkaline, sandy prairie soil by various levels of

treatment of sulfuric acid.

Soil tested at depth of—

Concentrated sulfuric acid used per square foot

(fluid ounce)^ O-J^ inches 0-8 inches

(pH) ipH)

0 7.5 7. 3

>i 6. 8 6. 8

}i 6. 2 6. 5

y^ 5. 8 6.2

Vi 5. 6 6. 0

1 Before dilution to about 2-percent solution. Soil was

treated in the spring and tested in the fall of the same year.

The difference in values for 0- to 4-inch level, as

compared with the full 0- to 8-inch shows that

there is a more marked change in the surface 4

inches than in the top 8 inches.

A standard practice in many Lake States nurseries is to apply commercial sulfuric acid, diluted

to 2 percent by volume, at the rate of Ke to Ke fluid

ounce per square foot immediately after the seed

are sown. Its purpose is to control damping-off,

but it has also been of some value in weed control

{173). Turner {177) found treatments of %6 to %^

fluid ounce per square foot very beneficial but observed no appreciable carryover benefit from one

crop to another. He also found that spring application of the acid on fall-sown beds was successful,

the stand per square foot in treated beds being

77.1 trees while in untreated beds it was only 30.1

trees. Others, however, have found some danger

of acid injury by this practice.

If sulfuric acid does not remedy soil alkalinity,

commercial-grade flowers of sulfur (% to ](¿ avoirdupois ounce per square foot) may be raked into the

soil to a depth of about 4 inches several months to

a full year ahead of seeding. This reduces pH

somewhat more than does the usual sulfuric-acid

treatment and there is less risk of injury, especially

if applied a year in advance of seeding. In terms

of equivalent effectiveness in acidifying power,

every 3 avoirdupois ounces of flowers of sulfur is

about equivalent to 5 fluid ounces of sulfuric

acid {39).

43
Nitrogen.—The addition of peat or muck will

supply nitrogen to the soil. Well-rotted animal

manures used at 10 tons or more per acre also are

a good source of nitrogen and organic matter, but

they may increase the damping-off and, in newly

prepared seedbeds, weed problems. Animal manures have been used with considerable success,

however, on transplant areas or with cover crops.

If the percent of total nitrogen in the nursery

is at the standard prescribed for the species (table

10, p. 42), the addition of inorganic sources of

nitrogen as a top dressing or so-called 'liquid fertilizer^' usually is not necessary. However, if

symptoms of deficiency of nitrogen show up, particularly in spruces in the form of short yellowishgreen needles, a treatment of liquid fertilizer consisting of 200 to 300 pounds per acre of 20-percent

ammonium sulfate is helpful. Other readily soluble nitrogen carriers may be used instead, such

as ammonium nitrate at 100 pounds per acre.

Phosphorus.—Some soils rich in iron have the

capacity to fix a considerable amount of phosphorus, thus making it unavailable for plant

growth. In one northern Wisconsin nursery with

a strong phosphate deficiency, the first application

of 200 pounds of 20-percent superphosphate resulted in no benefit because of iron fixation. The

addition of 400 pounds, however, greatly improved

the growth of jack pine stock. Extensive experience with experimental plots in northern nurseries shows that for tested soils having a phosphate

deficiency the minimum treatment is 300 pounds

of 20-percent superphosphate or its equivalent for

jack and red pines, and 400 pounds for white pine,

spruces, or hardwoods. Amounts of 400 to 600

pounds per acre gave good results in numerous

nursery fertility trials.

Phosphoric acid may deserve more trials as a

fertilizer. In one test at the Hugo Sauer Nursery,

the application of 0.8 fluid ounce of the material

per square foot gave a 32-percent increase in

weight of 3-0 white spruce. Heavier treatments

gave even greater contrast (table 13). Applications made in the fall at the time of seeding increased the stand 6 to 19 percent compared with

the checks, while treatments applied in the spring

decreased the stand by 9 to 21 percent, probably

because of acid injury.-

Since phosphoric acid tends to lower the pH of

the soil, treatment may be undesirable where the

pH is lower than 5.0. However, for moderately

acid or neutral soils (pH 6,0 to 7.5), treatment

may be worth testing at a dosage of about % to %

fluid ounce per square foot, applied in a dilute

solution. Phosphoric acid in liquid form, obtained in connection with superphosphate production, is now marketed in tank-car quantities to

California agriculturists. It has significant

amounts of iron, magnesium, sulfur, manganese,

and other elements that may enhance crop

response.

Reylaceahle hases.—Most nursery soils are

usually supplied well enough with replaceable

bases, such as calcium and magnesium, to grow

satisfactory conifer crops. Hardwoods have a

higher requirement. Deficiencies can usually be

corrected by applications of about 10 tons of

manure, or duff and humus collected under hardwood stands. The addition of )^ to 1 ton of

ground limestone may be necessary in strongly

acid soils (pH 4.0 to 4.5) to produce good growth in

blocks devoted exclusively to hardwoods.

FERTILIZERS

Peat.—Because of its high water-holding capacity, moderate nitrogen content, and capacity to

improve base-exchange relations and carryover

effects of commercial fertilizers, peat is a valuable

soil amendment in forest nurseries (fig. 23). Fortunately, huge deposits of peat occur in the

sphagnum swamps of the Lake States and are

readily accessible. Many nurseries, therefore,

develop their own sources of peat. Before a

swamp is developed for this purpose, a survey

should be made. Depths of peat at a dozen or

more places should be recorded and a rough estimate made of the amount available. For economical operation, at least 5 to 10 thousand cubic

yards of peat should be present on any site where

mechanical excavation is intended.

From 6 to 10 samples should be taken from

different depths to determine if the peat has a pH

between 4.5 and b.b (up to 6.5 or 7.0 is satisfactory

for hardwood nurseries), a total nitrogen content

of 2.0 percent, and a base-exchange capacity of

70 milliequivalents per 100 grams (190).

TABLE 13.—Effects of phosphoric acid soil treatment on 3-0 white spruce

Phosphoric acid applied per square

foot of bed (fluid ounces)

Len gth Green weight

Stem

diameter

Top Root Top Root Total

Inches Inches )U inch Grams Grams Grams

4. 8 6. 00 7. 7 2.48 1. 22 3.70

5. 4 , 4. 70 7.9 3. 12 1. 15 4. 27

5. 5 4.75 8. 2 3.55 1. 32 4.87

5. 4 6.40 8.6 3.63 1. 72 5. 35

6.0 6. 20 8. 8 4.08 1. 75 5.83

Top-root

ratio

0__

%-

%-

1%

2__

2.03

2. 71

2. 69

2. 11

2. 33

44 Agriculture Handbook 110^ Ü, S. Department of Agriculture
FiGXTRE 23.—Peat enhances the effect of commercial

fertilizers. This 2-0 jack pine was grown on an area

that had been fertilized 3 years earlier and had produced a crop of 1-0 jack pine. Left, 2 plants from the

area where only commercial fertilizers had been used;

right, 2 plants from area treated with commercial fertilizer plus 20 tons of dry peat per acre FertUizer in

each case was 400 lbs. of 20-percent ammonium sulfate,

600 lbs. of 20-percent superphosphate, and 160 lbs. of

50-pereent muriate of potash per acre.

Mechanical excavation reduces the cost of peat

by 50 to 75 percent over that dug by hand. Several

hiethods have been developed by Lake States

nurserymen by which peat has been excavated at

a cost of $0.25 to $0.60 per cubic yard. Most of

these methods utilize a draghne (fig. 24). However, steam or diesel shovels, such as those used by

contractors, are effective for excavating peat about

3 feet deep. When close to the nursery, the peat

can be stockpiled on the edge of the swamp. If

the swamp is at some distance, the peat usually is

haiiled by tractor to the nursery and stockpiled or

used in compost pits.

It is well to remember the following: " /

1. The use of large amoiuits of raw peat, especially if applied in the surface layers, may cause

potash and phosphate starvation (191).

2. Peat should be thoroughly and uniformly

combined with the soil by tilling it in as deeply as

possible and it should be supplemented by mineral

fertilizers.

3. If peat is applied on a weight basis, a large

part of the total weight is water. For example,

H. A. Barton of the U. S. Forest Service found

that a cubic yard of peat, stockpiled in a welldrained site for several months and weighing 850

pounds, had an oven-dry weight of only 134 pounds.

4. Where no rototülers are available and the

peat is in rather large chunks, it should be shredded

before spreading. A shredder can be made from

the cylinders and concaves of an old threshing

machine mounted on the chassis of an old truck

and with a 20-hp. motor with 11-inch pulley for

power, a 10-inch pulley on the shredder, and an

endless conveyor belt to carry the shredded peat

directly to a stockpile or into a manure spreader

i^9).

The method of mixing and applying peat or

compost varies with the equipment and facilities

available. The simplest method is to apply about

50 to 100 cubic yards of peat per acre directly on

the nursery site with a manure spreader. NecesFiGURE 24.—A dragline setup used in removing peat

from spruce swamps.

(Hugo Sauer Nursery,

Rhinelander, Wis.)

Forest A^ursery Practice in the Lake States

408189 =—58 4

45
sary amounts of mineral fertilizers, based on soil

analyses, may be applied with the peat or separately. Because stockpiled peat may remain frozen

late into the spring, it is desirable to spread the

peat in the fall.

Duff.—Duff is a highly prized material for nursery fertilization. It is rich in organic matter,

high in water-holding capacity and beneficial microorganisms, and well balanced as regards content of

nitrogen, phosphorus, potash, lime, and minor elements (table 14) {2, 87, 105, 190).^ A factor that

usually prevents its extensive use is the high cost

of labor required to rake it into piles and then

carry it on trays or litters to nearby trucks. Sometimes the long haul involved is also expensive. Although northern hardwood stands of sugar maple,

yellow birch, basswood and hardwood-hemlock are

the preferred source for duff, aspen or aspen-paper

birch stands may provide a cheaper source because

of their abundance and wide distribution.

Some nurseries may be close enough to larger

towns to make arrangements with city officials

to obtain the leaves swept up from the streets in

the fall. Such an arrangement, made by the

nursery at Winona, Minn., produced from 400

to 600 tons of dry leaves a year; the nursery paid

for hauling the material from the city to its compost pile.

Ordinarily, duff is used in composts, but it has

also given excellent results when applied directly

to the soil with other fertilizers. In most cases,

5 to 10 tons of duff, along with peat and commercial fertilizers, are adequate. Excellent results

were obtained at the Butternut Nursery in Wisconsin by using 20 cubic yards of hardwoodhemlock duff and 40 yards of raw peat per acre

{80).

Compost.—Many Lake States nurseries have

concrete compost pits where they retain specified

mixtures of peat, hardwood duff, and mineral

fertilizers for 1 to 2 years. Sometimes these

materials are placed in alternate layers. At

other nurseries, measured materials are shoveled

into a peat-shredding machine from which they

drop directly into the compost pit (fig. 25).

A rather well-balanced mixture for an acre of

badly depleted nursery soil consists of 50 cubic

yards of peat, 5 cubic yards of duff, 300 pounds

of 20-percent ammonium sulfate, 500 pounds of

20-percent superphosphate, and 200 pounds of

50-percent muriate of potash. First, the three

commercial fertilizers are mixed. Then, to get

a reasonably good mixture, 10 cubic feet of peat,

1 cubic foot of duff, and 7 pounds of the mixed

commercial fertilizer are proportioned roughly

as they are shoveled into the hopper. By the

time they have passed through the shredder and

dropped into the pit, they are rather well mixed.

For best composting action, the organic material

must be moderately moist, but not wet; if too dry,

it should be sprinkled.

As an economy measure, many nurserymen now

make up a concentrated compost. For example,

in the compost mentioned in the preceding paragraph, there are roughly 20 pounds of commercial

fertilizers per cubic yard of organic matter. In

the concentrated compost, there are 60 pounds of

commercial fertilizer per cubic yard of peat, plus

0.3 cubic yard of duff; only 17 cubic yards of this

triple-strength compost is applied to the nursery

together with 33 cubic yards of peat. The material is worked in by rotary tiller.

Cover crops.—Cover crops are desirable in

Lake States nursery culture for the purpose of

TABLE 14.—Analysis of surface soil layers in aspen stands in the Lake States

SOIL CHARACTERISTICS

Soil horizon

Average

thickness

Organic

matter

Total

nitrogen

Replaceable

calcium

per 100

grams

Baseexchange

capacity

per 100

grams

Available

potash

Available

phosphorus

Duffi

Inches

0. 55

. 65

1. 20

3. 40

Percent

50.2

26. 4

7.5

1. 1

Percent

0. 938

.529

. 216

. 035

Milliequivalents

27. 1

21. 8

7. 5

1. 4

Milliequivalents

52. 2

44.4

16. 9

5. 9

Parts per

million

1,240

790

73

54

Parts per

million

161

Humus ^ 105

Ai 23

Ao 34

RATIO OF VALUES TO THOSE IN A2 LAYER

Duffi__

Humus '

Al

A2

46

24

7

1

27

15

6

1

19

16

5

1

23

15

1

1

1 Partially decomposed leaves.

2 Black layer of humus below duff.

46 Agriculture Handbook 110^ Ü. S. Department of Agriculture
FIGURE 25 —Filling a compost pit. Peat, hardwood-hemlock duff, and commercial fertilizers are shoveled into the

peat shredder in proper proportion. (Hayward Nursery, Wis.)

crop rotation and to add some bulk organic material to the soil. As early as 1909 Pettis {113)

suggested that one-third of the nursery area should

be in cover crop. Piett>rs and McKee (114) state

that the chief purpose of green manure is to

maintain organic matter, and that many legumes

under good conditions may add from 120 to 200

pounds of nitrogen to the soil per acre. They

list hairy vetch, Austrian winter peas, Crotalaria,

alfalfa, sweetclover, and crimson clover as tlie

most important cover crops in the United States.

Among cover crops used in Lake States forest

nurseries are rye, oats, soybeans, and field peas.

Commercial nurseries usually located on better,

less acid soils may use alfalfa or clover seeded at

8 to 12 pounds per acre, or hairy vetch at 3 to 4

pecks per acre. The clovers and alfalfa usually

require a soil pH of about 6.5 or higher {24)-

Since most large-scale producers of pine and

spruce for reforestation in the Lake States are

located on soils with pH in the range 4.8 to 6.2,

they have depended on rye as a standard cover

crop. Soybeans have been used in the southern

part of those States. Rye will grow fairly well

in moderately acid soils with pH range of 5.2 to

6.2. It tolerates more acid soils than oats or

Forest Nursery Practice in the Lake States

soybeans which prefer a pH of 6.0 or slightly

higher (25).

Tests of six different species of lupine at the

Hugo Sauer Nursery, Rhinelandcr, Wis., indicate

that several of them have real possibilities as

leguminous cover crops even on soils with pH of

about 5.0. Blue annual bitter lupine produced

from 4,260 to 6,510 pounds of ovendry material

per acre on unlimed and limed plots respectively,

with a total nitrogen contribution to the soil of

66 to 102 pounds per acre. Sweet yellow lupine,

a nonalkaloid species suitable for livestock feed,

produced from 5,450 to 5,570 pounds of ovendry

material per acre on unlimed and limed plots,

respectively, with a total nitrogen contribution to

the soil of 82 to 84 pounds per acre.

Finely ground dolomitic limestone was added

at the rather mild rate of about 1,000 pounds per

acre in the above experiments. The lupine seed

was treated mth special lupine inoculum before

seeding in June, and was harvested in the fall.

The lupines out-produced rye by about 3 to 1 in

terms of organic matter and total nitrogen content.

Lupine seed is available from commercial seed

houses in the Southeast.

47
Lupines have also done well when spring-seeded

in cool-climate areas lying at high elevations,

particularly at Savenac Nursery, Haugan, Mont.,

and Mt. Shasta Nursery, McCloud, Calif. They

are used extensively in southeastern United States

as winter-sown cover crops.

Legumes and other cover crops afford maximum

addition of bulk organic matter when the entire

crop, including both root and top, are plowed

under. Legumes are plowed under shortly after

they have attained full flower or are starting to

form pods or seeds, while rye or oats are plowed

under just as seed heads start to form. The tops

contain the bulk of the organic matter and a large

part of the total nitrogen. Some Lake States

nurserymen mow legumes in the summer and let

them lie until fall to reduce soil blowing.

Manure.—Manure has not been used to any

great extent in public nurseries in the Lake States

but has for years been a favorite in commercial

nurseries for lining out areas. It improves tilth,

water-holding capacity, aeration, and temperature

relations {184), and often doubles or trebles the

number of useful soil organisms in the top 9 inches

of soil {1S3).

The chief problems with manure are frequent

loss of the valuable liquid part that contains much

of the nitrogen, volatilization of the ammonia as it

ferments, and improper time and rate or manner

of application. It is generally deficient in phosphate. A good treatment for transplant areas or

ornamental blocks is 8 to 10 tons of manure per

acre supplemented by 250 to 300 pounds of 20-

percent superphosphate.

Manure generally is considered to promote

damping-off and hence is not recommended for

areas that are to be seeded to conifers. It often

contains considerable weed seed. In general

order of decreasing nutrient value, the manures

rate as follows: chicken, sheep, hog, horse, and

cattle.

Liquid Jertilizers.—Although a number of liquid

fertilizers have been used in Lake States and otlier

nurseries to correct nutrient deficiencies, commercial nurserymen have long preferred nitrophoska

(15-30-15) " (151). It is often used at the rate

of 4 ounces per 3 gallons of water applied per

4- by 12-foot bed.

In an experiment at Hugo Sauer Nursery in

1937, and followed into the field, fertilization with

nitrophoska increased the amount of plantable

2-0 red pine stock by 30 percent and second-year

field survivals by 3.0 to 7.5 percent (tab)e 15).

The length of needles and terminal buds nearly

doubled and stem caliper increased by this treatment (fig. 26). Considering both costs and results

obtamed, a treatment of 400 pounds per acre of

15-35-15 fertilizer gave best results.

Since straight phosphate fertilizers are not

readily soluble in water, combined fertilizers, such

" Three values used in connection with fertilizers, for

example 15-30-15, refer to percent of nitrogen, phosphorus

(as PaOs), and potash (as KjO) respectively.

TABLE 15.—Effect of liquid fertilizers on ihe grade,

size, and ñeld survival of 2-0 red pine

Amount of

nitrophoska

Classification of

nursery stock i

Green

weight of

average

2-0 seedling

Field

survival

applied

(pounds) PlantableGood Excellent

First

year

Second

year

0

200

400

800

Percent

64

76

94

94

Percent

14

16

48

54

Percent

4

10

24

36

Grams

1. 55

1. 79

2. 73

3. 14

Percent

71. 6

72.8

80. 4

72.4

Percent

54. 7

62. 2

58. 9

57. 7

1 In classifying nursery stock, trees with a caliper of %<

inch and over were considered plantable; %,i inch and over,

good; %4 inch and over, excellent. All stock had fairly

good balance. Trees not meeting the caliper specifications

were discarded.

FIGURE 26.—Liquid fertilizers greatly improve growth and

color. These are 2-0 red pine. The two trees at the

left received no treatment. The two trees at the right

received 400 pounds per acre of 16-35-15 nitrophoska.

(Background is 1-inch squares.)

48

as ammo-phos (11-48-0) or nitrophoska (15-35-

15), are used at rates of 200 to 400 pounds per

acre. Potash, readily soluble in water, can be

applied in 50-percent muriate of potash or 50-

percent sulfate of potash at the rate of 150 to 200

pounds per acre. An alternative is to use a

combined fertilizer, such as potassium nitrate

(13-0-44), at 200 to 300 pounds per acre. Liquid

fertihzers can be applied in late May and again in

June or early July.

In small nurseries liquid fertilizers are applied

with a tank or drum mounted on wheels, such as

an acid cart. In large-scale operations, they can

be pumped directly out of a tank into the overhead

Agriculture Handhook 110, U. S. Department of Agriculture
pipeline {30), run into the sump in which the

pump intake is located (138), or forced into the

pipeline with an injector (fig. 27) or by means of

a venturi tube near the oscillator while the water

system is in operation (82). The venturi-tube

method is advantageous in that no outside

sources of power or pumps are necessary. As the

overhead is turned on, fertilizer automatically is

drawn into the overhead line from a tank located

on a pickup truck or on skids and connected with

two hoses to the tube.

55-ga). barrel

""Concentrated

solution

Pump

FIGURE 27.—Injector for forcing liquid fertilizers into

overhead irrigation systems. (Manistique Nursery,

Manistique, Mich.)

Commercial fertilizers.—^A few of the principal

commercial fertilizers that supply various elements

are listed below. There are, of course, many more.

The 1938 Yearbook of Agriculture or any standard

textbook on fertilizers, such as that by Collings

(33), lists these in more detail.

Nitrogen {N)

Ammonium sulfate, 20 percent

Ammonium nitrate, 33-35 percent

Sodium nitrate, 16 percent

Dried blood, 6-14 percent

Urea, 46 percent

Calurea, 34 percent

Calcium nitrate, 17 percent

Phosphorus (as P2O5)

Superphosphate, 16-20 percent

Treble superphosphate, 45-48 percent

Basic slag, 5-20 percent

Potassium (as K2O)

Potassium sulfate, 48 percent

Potassium chloride, 48-62 percent

Mixed fertilizers supplying two or more elements

Nitrophoska, 15-30-15 '' or 15-35-15

12 See footnote 11, p. 48.

Forest Nursery Practice in the Lake States

Ammonium phosphate, 11-45-0 or 16-20-0

Potassium nitrate, 13-0-44

Animal tankage, 5-9-0 to 10-14-0

Bonemeal, 3-20-0

Milorganite, 6-2.5-0

MALNUTRITION SYMPTOMS

Malnutrition often can be detected if some of

its symptoms, such as abnormal foliage color and

bud development, are present in the stand.

Symptoms of malnutrition are described in table

16 and the following paragraphs. Although certain treatments may give short-term relief for the

affected crop, remedial measures should be

applied before the area is seeded again.

1. Potash deficiency in red pine in one study

was marked by a stunting of growth; the needles

turned bluish green and became necrotic (tan to

copper in color) at the ends, especially those at

the base of the plant (70). In another study

there was general chlorosis, browning and death of

the needles, and decreased growth and needle

persistence (68).

2. Potash deficiency in white pine was evidenced

by necrosis at the tips of the needles all over the

plant, and the needles were slightly copper colored

(70). Purpling of white pine needles also has

been noted as a symptom of phosphate deficiency.

3. Magnesium deficiency in several of the pines

is indicated by a yellowing of the needle tips (94) •

In several instances, particularly where there was

considerable calcium in the irrigation water,

chlorosis of ponderosa pine, Douglas-fir, jack pine,

and lodgepole pine has been corrected by use of a

1-percent spray of ferrous sulfate applied at 10-day

intervals in the growing season (78).

DIVIDENDS FROM NURSERY

FERTILIZATION

There is probably no cash outlay in nursery

operation that pays such large and consistent dividends as maintenance of the proper fertility level

of the soil. Studies at the Lake States Forest

Experiment Station show that the percent of

plantable stock often can be raised from 70 or 80 in

unfertilized beds to 90 or more in treated beds

(fig. 28). , ,. ,

Each 10-percent increase m plantable stock may

be equivalent to a gain of several hundred dollars

obtained by spending a fraction of that amount

for fertilizers. For example, an acre of nursery

area will produce about 750,000 2-0 red pines,

grown at the usual density. The value of such a

crop is at least $5 per 1,000 trees, or $3,750 per

acre. If the number of plantable trees per square

foot is boosted 10 percent by fertilization, the

value of such increased production is $375 per acre.

The combined cost of fertilizers and their application in the nursery usually will be from $50 to $100

per acre, or less if liquid fertilizers are used. Therefore, the net profit from nursery fertilization in

49
TABLE 16.— Symptoms qf malnutrition injorest nursery stock ^

DeftoieH€y or excess Symptoms Class of stock and

species

Treatment required per acre

Nitrogen deficiency_

Phosphorus deficiency.

Potash deficiency.

Excessive soil acidity

(pH 4.0 to 4.5) resulting in magnesium

deficiency.

Excessive soil alkalinity

(pH 7.7 to 8.8).

Western part of Minnesota.

Deficiency of beneficial

mycorrhizae on roots.

Prairie soils.

Tron deficiency. Mostly

alkaline prairie soils

with pH 8.0 to 8.8 or

higher.

Pale yellowish-green,

foliage.

short

Purplish-bronze needles. Needles very short, buds unusually short at end of

season.

Entire needles often yellow;

! tips often dead.

Golden yellow color of outer

third of needle. Remainder

of needle normal or deep

green. (Symptom may also

result from use of ammonium sulfate, sulfuric acid,

or very acid peat on rather

acid soils).

Pale yellow foliage. Short

needles. Short terminal

bud. Lateral bud development poor.

Extremely patchy, uneven

size of trees in beds. Ends

of foliage often are brown or

dried up. Terminal buds

short. Very heavy mortality in second-year seedbeds.

Yellow splotches devoid of

chlorophyll on leaves.

2-0, 3-0, and transplant white pine

and white spruce.

1-0, 2-0 white spruce.

1-0 jack pine

1-0 and 2-0 jack pine,

and 2-0 or older

red pine.

2-0 jack pine, 2-0

Scotch pine, 2-0

ponderosa pine, 2-0

red pine.

2-0 ponderosa pine,

2-0 Scotch pine,

2-0 and 3-0 spruce

(blue, white, western white).

1-0 and 2-0 Siberian

elm, American elm,

and other hardwoods.

300 pounds per acre of 20 percent ammonium sulfate, or 200 pounds in each

of 2 successive treatments at 4-week

intervals in solution. For next crop

use compost and peat abundantly,

400 pounds of ammonium phosphate or

nitrophoska in solution. For next

crop use 600 pounds per acre of 20-

percent superphosphate before seeding.

200 pounds of 50-percent sulfate of potash in solution. For next crop use 240

pounds of potash per acre before

seeding.

Rake 1,000 pounds of dolomitic limestone between drills on badly affected

spots. Work in with cultivator. For

next crop, use 500 pounds dolomitic

limestone per acre, if devoted to transplants or a cover crop.

Rake 1 to 1% ounces per square foot of

aluminum sulfate between drills and

work into soil. Water. Or apply 1

ounce in weak solution and water

afterward.

Too late to salvage much from 2-0 or

3-0 beds. For next crop, grow transplants on area with seedlings from

well-established nursery; or haul in

soil from old nursery at }^ pound per

square foot. Acidify surface soil to

pH 6.0.

Rake 1 ounce per square foot of iron sulfate into soil between drills. For next

crop, use ñowers of sulfur at % ounce

per square foot to acidify soil and increase availability of iron.

1 Based on observations of the Lake States Forest Experiment Station in Wisconsin, Michigan, Minnesota, and North

Dakota.

this instance would be from $275 to $325 per acre

for every 10-percent increase in production of

plantable trees.

In one nursery, the amount of plantable 1-0

jack pine was increased 27 to 40 percent by fertilization. A slight but consistent gain in second-year

field survival was not significant statistically

(table 17). The cost of fertilization per acre was

$30 to $80 in 1937 and the increase in value of the

stock produced was $150 per acre for each 10-

percent increase in amount of plantable stock.

Occasionally, an extreme deficiency of one fertilizer element causes actual starvation and mortality of trees in the nursery. In one area where

there was a strong phosphate deficiency—only 23

parts per million of available phosphorus (as

P2O5)—white spruce seedlings in unfertilized beds

were very short, purplish bronze in needle color,

and many died the second season (fig. 29). In

adjacent fertilized beds, the needle color was

normal and there was no heavy second-year loss.

Fertilizers that are slow to dissolve provide a good

source of phosphorus in very sandy soils subject to

leaching. In one experiment the size of stock was

increased by the use of 20 tons of dry peat along

with 1,000 pounds of bonemeal per acre.

Based on a large number of nursery fertilization

tests, the average gain in field survival 5 to 8 years

after planting was only between 1.5 and 2.3 percent. However, the best treatments gave increases in field survival of 3.9 to 14.0 percent 2

to 3 years after planting and 3.0 to 16.9 percent

about 7 years after planting (table 18). Since

gain or loss from, best treatments where more than

one field test plot was involved is compared with

the average survival in the check plots for that

individual test and not with the average survival

for all check plots combined, the average gain

based on all treated plots provides a better although somewhat conservative figure for the

probable gain in field survival. These results

refute the theory that stock produced for droughty

or difiäcult planting sites should be sharply restricted in nutrients while in the nursery. In the

50 Agriculture Handbook 110^ Ü. S. Defwrtnient of Agriculture
):

1

J \

B

FIGURE 28.—Eflfect of fertilizer on 3-0 white spruce produced on a soil of low fertility. Fertilization was as

follows: A, 400 lbs. ammonium sulfate, 600 lbs. superphosphate, 160 lbs. 50 percent potash, and 14 tons of

peat per acre; B, 200 lbs. superphosphate per acre; C,

400 lbs. ammonium sulfate, 600 lbs. superphosphate,

and 80 lbs. muriate of potash per acre; D, none. (Background is 1-inch squares.)

>»^: . f^- , -'*«»«%

F-372125

FIGURE 29.—Bed of 2-0 white spruce at right received

200 lbs. of ammonium sulfate and 80 lbs. of potash per

acre; lack of phosphates in this bed was acute and there

was outright starvation of the plants. Bed at left received 400 lbs. of 20-percent ammonium sulfate, 400

lbs. of 20-percent superphosphate, and 80 lbs. of 50-

percent muriate of potash per acre.

tests, the effect of nursery fertilization on increased height growth largely disappeared 5 to 8

years after the trees were planted (table 19).

When both height and survival are considered,

the addition of peat alone in the nursery was of

little value, probably because the raw peat absorbed part of the soil nutrients. However, peat

applied with mineral fertilizer or in compost form

gave better results. Mineral fertilizers alone

gave surprisingly good results, although in the long

run their use without occasional additions of

organic matter probably would result in gradual

reduction of the nursery soil's capacity to produce

prime stock.

Forest Nursery Practice in the Lake States

TABLE 17.—Increase infield survival and -production of plantable 1-0 jack fine hy fertilization in

the nursery

Nursery treatment

per acre

No treatment

8 tons compost ^ (ovendry basis)

20 tons peat (ovendry

basis)

20 tons dry peat -1- 400

pounds 20-percent ammonium sulfate -|- 600

pounds 20-percent superphosphate -\- 160

pounds 50-percent potash

400 pounds 20-percent

ammonium sulfate -|-

600 pounds 20-percent

superphosphate -|- 160

pounds 50-percent potash

Proportion of trees

rated as '—

Plantable

Percent

60

92

100

95

Good Exc 1

lent

Percent

12

45

30

67

Secondyear

field

survival

(thrifty

trees)

22

Percent

7

22

10

47

12

Percent

69. 6

73. 0

77.3

77.0

70. 7

1 In rating the nursery stock, plantable trees had a stem

caliper of %4 inch or greater; good, |^é4-inch caliper or

greater; and excellent, %4-inch caliper or greater. All

stock had good balance.

2 Compost consisted of hardwood-hemlock duff, acid

peat from spruce swamps, and complete N, P, K commercial fertilizers.

THE MYCORRHIZA PROBLEM

Mycorrhiza are beneficial fungi that live in association with conifers {89) and some hardwoods.

They aid the plants in the assimilation of phosphate, nitrogen, and potash, and perhaps of other

nutrients as well {49, 90, 91, 128). Their lack

or scarcity, especially in nonforest soils such a,s

prairie land, or in former forest land now in agricultural crops or grass, can spell partial {187) or

complete failure of subsequent seedings or plantings of conifers. In former forest soils mycorrhiza

disappear rapidly for lack of host plants and,

perhaps, moisture {75). The presence of humus

may extend their survival beyond the usual spq-n

of 1 to 2 years.

Lack of mycorrhiza has not been a particular

problem in newly established nurseries in the

Lake States because many of these were located

on recently cleared forest land. In several instances, however, parts of nurseries were placed

in old fields or pastures. In these areas the first

crop of seedlings was decidedly uneven in size and

development in spite of heavy fertilization.

Patchwise, this was attributed to uneven distribution of mycorrhiza living on spottily distributed organic matter. After two crops of

trees had been harvested, tree size became quite

51
TABLE 18.—Efects oj nursery fertilizers on survival ojfield-planted conifers in the Lake States

Age

class

Age of plantation when

Aver

aere

-

Gain or loss in survival compared with check plot when

treatment was—

Basis

Species

counted survival

in untreated

check

plots

Peat only Mineral only Compost Peat and

mineral

Field

test

plots

Range

Average

Average

Best

treatment

Average

Best

treatment

Average

Best

treatment

Average

Best

treatment

Trees

Jack pine

Do

1-0

2-0

2-0

2-0

2-0

3-0

3-0

2-0

2-0

3-0

3-0

3-0

3-0

Years

~""i-3

5-8

" "l-2

5-6

~"~6-7

Years

3.0

2. 6

7. 0

3.0

8.0

L8

5.7

3,0

8.0

2. 0

6.5

2. 0

7.0

Percent

77

76

78

77

73

72

60

82

77

88

78

87

70

Percent

+ 2. 0

+. 1

+.6

+ 5.0

+ 4. 0

-8. 0

-7.0

+ 6. 0

+ 5. 0

-4.0

0

+ L0

-2.0

Percent

+ 2. 0

+. 1

+.6

+ 5. 0

+4.0

-8.0

-7. 0

+ 6.0

+ 5. 0

-4. 0

0

+ L0

-2. 0

Percent

0

+.2

+.5

+ 2.0

0

+ 10.3

+ 15.5

+ L0

+4. 0

+ L0

+ 5. 5

+.2

+.2

Percent

0

+13. 6

+ 13. 1

+ 2. 0

0

+ 26. 5

+46. 0

+ L0

+ 4. 0

+ n. 0

+ 19.0

+ 7. 0

+ 18.5

Percent

+ 3. 0

-.6

+ 2. 8

+ 3.0

+ 3. 0

+ 3,0

-4.0

+ 3. 0

-2. 0

-6.0

+ L0

+ 2.0

+ 2.5

Percent

+ 3.0

+ 3.8

+ 3.8

+4,0

+ 3.0

+ 5. 0

-2. 0

+ 7,0

+ L0

-2. 0

+ 2.0

+ 5. 0

+ 9.0

Percent

+ L0

+.6

+ L8

+ 3. 0

+ 3. 0

+ 13.0

+ 2. 5

+ 2, 0

+4. 0

+ L0

+ 2. 0

-6,5

+ 5. 0

Percent

+ L0

+ 4, 0

+ 2,0

+ 3,0

+3.0

+ 13, 0

+ 7.0

+ 2.0

+ 4, 0

+ L0

+ 2. 0

-6, 5

+ 5.0

Number

1

18

14

1

1

4

3

1

1

3

2

4

4

Number

4, 000

76, 500

Do _ -__ _-

61, 300

Red pine

Do

2, 400

2,400

Do _ _-

17, 700

Do 11, 300

White pine

Do

2, 400

2,400

Do 15, 200

Do _

8, 800

White spruce

Do

20, 550

20, 550

Weighted average, all 1- to

3-year plantings _ 78 +.3 + .3 + L6 + 14. 0 +.5 + 3. 9 +.8 +4, 0 32 138, 750

Weighted average, all 5- to

8-year plantings 75 +.3 + .3 + 2.3 + 16. 9 + L5 + 3.7 + 2.3 + 3. 0 25 106, 750

! 1 1 1

TABLE 1 9.^—Efects of nursery fertilizers on height offield-planted conifers in the Lake States

Species Age

class

Age of plantation

when measured

Average

height

of trees

in check

plot

Gain or loss in height compared with

check plot when treatment was—

Range Average Peat

only

Mineral

only

Compost

only

Peat and

mineral

Jack pine 2-0

2-0

3-0

2-0

2-0

3-0

Years

5-8

Years

7.0

8.0

5.7

8. 0

6. 5

7.0

Feet

7.8

3. 1

2. 1

2.8

3.3

1. 3

Feet

-0. 1

+. 1

+. 1

-.2

+. 1

+. 1

Feet

+ 0.2

-. 1

-. 1

-. 6

-. 2

0

Feet

+ 0. 1

-, 2

-, 1

0

+.2

0

Feet

+ 0, 1

TÎ PH "DITIP —. 1

Do 5-6 -, 1 — , 3

Do 6-7 +.2

White spruce 0

Weighted average), all s pecies 5-8 6. 9 5.34 -. 04 +.05 +.03 +. 04

1 _ ___ 1

D B U A C U A C D B B U D C A B U

FIGURE 30.—An experimental bed with 4 replications, each of which has 5 plots. A, B, C, and D in each instance

represent the 4 materials under test, and U the untreated check plot.

52 Agriculture Handbook 110, Ü. S. Department of Agriculture
uniform. Mycorrhiza has spread because of the

presence of host pines, good moisture conditions,

and such operations as floating, dragging, disking,

cultivating, and lifting.

In prairie soils such as those in western Minnesota and small areas of Wisconsin, lack of mycorrhiza could be a serious problem in newly

established conifer nurseries, and inoculation

would have to be made. The most feasible

method is to incorporate topsoil and dun' from

nearby planted stands of pine or spruce into the

top 2 to 3 inches of the seedbed. Another method

is to line out or transplant seedlings from an old

established nursery that produces large, thrifty

seedling conifers of uniform size in a soil obviously

well supplied with mycorrliiza.

These methods have the theoretical disadvantage of introducing damping-off or other disease

organisms into a new nursery site, but appear to

be the only ones yet feasible for large-scale operations. If the soil in the new site is about neutral

(pH 7.0), treatment with sulfuric acid, or other

acidifying materials, is absolutely necessary to

lower the pH to about 5.5 or 6.0 because mycorrhiza spread faster in a moderately acid soil than

in one which is neutral or alkaline.

EXPERIMENTAL PLOTS

There may be occasions when the nurseryman

will wish to make tests of fertilizers, fungicides, or

weed killers. For such purposes, experimental

plots 4 by 4 feet in size are recommended, and

they are best laid out in one or more long beds

that provide for 4 or 5 contiguous replications

(fig. 30). Such a bed samples more variation of

soil than a square or nearly square test area.

However, replication blocks may be scattered

over as many as 4 locations separated by as much

as 100 or 200 yards.

The plots in an experiment should be handled

as uniformly as possible. Where the experiment

involves pretreatment with a fertilizer or other

soil amendment, a fungicide, or a weed-seed

Iviller, it is best to mix the tree seed thoroughly

and then weigh out the exact amoimt for each

plot on a reasonably sensitive scale. Seeding

should be done by hand at a uniform depth (fig.

31), and seed covered by sifting soil over the

depressed seeded drills and smoothing it off

carefully with a board or the back of a rake. In

some instances the experimental beds may need

screening against rodents, birds, or larger animals.

Experiments involving trials of weed control or

liquid fertilizers may be superimposed on an

existing bed of uniformly stocked first- or secondyear seedlings or transplants. Counts can tlien

be made of weeds before and after treatment

and of trees injured or killed by the treatment.

In some experimental beds, counts of seedlings

are required in late spring and in the fall. In

others, only one final coimt before or after lifting

may be necessary. At the end of the trials or tests,

samples of the seedlings should be taken after

lifting by selecting mechanically every 5th, 10th,

or 20th seedling. The sample should be large

enough to provide 25 or 50 trees out of each small

bed. These sample seedlings provide a basis for

determining percent of plantable and premium

stock produced, total fresh or ovendry weight,

top-root ratio by weight, etc. Normally, the

results of any four like treatments are pooled by

average stand per square foot, number of plantable

trees produced per square foot, number of premium-grade or undiseased trees produced per

square foot, or average fresh or ovendry weight

per tree. If there are large and consistent differences in averages, the residts of the experiment are

quite apparent. If the differences are small, the

data can be analyzed by statistical methods (3^,

55,147,171). For this, assistance can be obtained

from a United States Forest Service Forest

Experiment Station or an individual familiar with

mathematical procedures.

FIGURE 31.—A closeup of a 4- by 4-foot experimental

plot and a flanged wooden roller that assures uniform

depth of seeding.

Hartley {66) recommends a procedure that will

often add to the general observational picture in

routine nursery operations. He suggests leaving a

few check areas that are treated differently than

the remainder of the nursery; for example, small

shaded or unshaded units, and units treated

differently as to watering, fertilization, or weed

killers. This shoidd provide clues to the relative

effectiveness of certain treatments, aid in isolating

possible causes of death, and help to explain differences in stand density or size.

Forest Numery Practice in the Lake States 53
AGE CLASSES OF STOCK NEEDED FOR

REFORESTATION

The age classes to be produced at a nursery will

depend on several factors. The most important

is the kind of stock required to assure good survival

in most years on the field planting sites (table 20).

Older age classes or transplants often are recommended for the more difficult sites and for windbreaks.

Many studies conducted in the Lake States

{57, 131, 132, H2, 159, 160) and in other areas

{104, 14.6) indicate an advantage in first-year field

survival of 10 to 40 percent for transplants over

seedlings. On the more difficult sites, transplants

may be necessary for good results and this fact

has a bearing on the age class grown in the nursery.

TABLE 20.—Age classes of stock to use in reforestation and windbreak planting in the Lake States ^

Species

For reforestation onAverage to easy sites Difficult sites

For windbreaks

Conifers:

Douglas-fir

Fir, balsam

Hemlock, eastern 2

Larch, European

Pine, Austrian

Pine, jack

Pine, ponderosa

Pine, red

Pine, Scotch ^

Pine, white

Redcedar, eastern

Spruce, black

Spruce, blue

Spruce, Norway^

Spruce, western white.

Spruce, white

Tamarack

White-cedar

Broadleaves:

Ash, black 2

Ash, green

Ash, white

Aspen, quaking^

Basswood

Beech, American 2

Birch, paper ^-

Birch, yellow 2

Cherry, black 2

Cottonwood, eastern __

Elm, American

Elm, rock 2

Locust, black

Maple, red

Maple, silver

Maple, sugar 2

Oak, red ^ . Oak, white ^ Walnut, black ^

2-2, 3-0, 4-0

2-2

2-1, 2-0

2-0, 1/2-0, 1-0

2-1, 3-0, 2-0

2-0, 2-1

3-0, 2-0, 2-1

2-1, 3-0, 2-0

2-1, 3-0

2-1

2-2

2-0

2-0

1-0

2-0

2-0

2-0

2-0,

2-0

2-0

2-0

2-0, 1-0

2-0

1-0, 2-0

2-0

1-0

2-0, 3-0

1-0

1-0

1-0

(')

2-2, 2-3, 3-2

2-2, 2-3

2-1, 1-2

1-1, 2-0

2-2, 1-2, 2-1

2-2, 2-1

2-2, 1-2

2-2, 2-1

2-1, 2-2

2-2, 2-1

2-2, 2-3, 3-2

1-1, 2-0

2-0, 3-0

3-0, 2-0

1-1, 2-0

2-0, 3-0

3-0, 2-0

3-0, 2-0

3-0, 2-0

3-0

2-0, 3-0

3-0, 2-0

2-0, 1-0

2-0, 3-0

2-0

3-0

1-0, 2-0

2-0, 1-0

1-0

W

2-2, 2-3, 3-2

3-2, 2-3, 3-3,

2-3, 3-2

2-1, 2-2, 1-2

2-2, 2-1, 1-2

1-1, 1-2, 2-0

2-2, 1-2, 2-1

2-2

2-2

2-2

2-2

2-2, 2-1

2-2, 2-3, 3-2

2-2

2-2, 2-3, 3-2

2-3, 2-2, 3-2

1-1, 1-2, 2-1

2-2, 2-3, 3-2

3-0, 2-0

2-0, 3-0

3-0, 2-0

3-0, 1-2

3-0, 2-0

2-2

2-0, 3-0

3-0

2-0, 1-0

3-0, 2-0

2-0

3-0

1-0, 2-0

2-0

1-0

(')

1 Age classes are listed in each category in preferred order. , , .. -x • 4-

2 Rarely used in reforestation because of difficulty of successful estabhshment due to deer, rabbits, site requirements,

or costly aftercare. , ,.,.,,.. 1 -, j- i, j.

3 Special care must be taken to assure proper seed source, adaptability to chmate, and good form when mature.

4 Planting of this species is largely experimental as yet.

5 1-0 or wildings, or 1-year rooted cuttings.

6 1-year rooted cuttings or 2-0, or wildings.

7 2-0 or 1-year rooted cuttings, or wildings.

8 Often established by direct seeding.

54 Agriculture Handhooh 110^ Ü. S, Department of Agriculture
Extensive observations in shelterbelt and farmstead windbreak planting have shown that transplants of conifers are necessary to obtain uniformly

good survival, especially on soils that are rather

fertile or where weed growth is likely to engulf the

trees unless they are cultivated. Small, spindly

trees are easily buried in cultivation or smothered

out by weed competition. The most favored age

class is 2-2 conifer stock, although for the slower

growing spruces 2-3 stock is sometimes necessary

to get a tree of sufficient height, thickness of stem,

and adequate root system to give uniformly high

survival.

Other factors that govern the classes of stock

to be produced are (1) the length of growing season

and the relative fertility level in the nursery, both

of wiiich affect the size of stock produced; (2) the

inherent growth characteristic of the different

species and age classes (fig. 32); (3) season of

seeding; and (4) the time of transplanting. The

effect on stock size from these sources may be

great enough at some nurseries to call for adjustment in .the age classes recommended in table 20.

Some nurseries are able to produce 2-0 red pine

and 2-0 white pine that are practically as large

and which will survive as well as 2-1 stock from

other nurseries. Transplants of some species,

such as red pine, grow well and increase very

appreciably in size during the first year in the

transplant beds. White spruce, on the other

F-345917, 422766, 4224^3

FinuRE Z2.—A, Typical 1-

year-old nursery seedlings. From left to right

the sets of two seedlings

are red pine, white pine,

jack pine, and white

spruce. B, Typical 1-0

red oak. C, Typical 2-0

white ash. (Background

is 1-inch squares.)

\ ! 11

" !

U

4^|y^rl- ^1

^- -i-'*álFmjt»^-:=f^^§II

V

X 1 rV 1

T J

J

/

' -^ 't

''' i» aiÎT*"' -^^TK..^. / ^! --

jîlmfe4r^-^---

\ *' 1 ëi--<i^' •mmmt—

M "^^ /uWi ^In^Bi H"

jf^ !!• li ^-Wff

Forest Nursery Practice in the Lake States 55
hand, grows very slowly the iirst year in transplant

beds in most Lake States nurseries, and only in

its second year does it put on good growth. It

usually increases in weight during its 4th year as

much as or more than it did the previous 3 years.

Hence, white spruce usually is grown to 2-2 age,

which produces an excellent tree of good size, fine

root system, and good balance; it survives and

grows well under adverse field conditions. Older

white spruce stock may be required for especially

difficult planting chances, such as those commonly

encountered in shclterbelt establishment.

In some nurseries 2-0 jack pine tends to become

rather topheavy, so seeding is delayed until June

to produce a shorter, well-balanced tree referred

to as lK-0 age class (fig. 33).

Fall-sown seedbeds invariably produce stock

superior in size to spring-sown beds. This is

especially striking and of importance for certain

age classes that are difficult to develop to adequate

size for field planting as seedling stock. Among

these critical age classes are 1-0 jack pine, 2-0 red

pine, and 2-0 white pine. For these age classes,

fall seeding may result in sufficient size increase

to produce 10 to 30 percent more plantable stock,

largely because more of the trees wUl come up to

the minimum caliper specification.

Stock measurements vary considerably by

species and age classes (tables 21, 22, 23, and 24).

For this reason, some species can be grown to

plantable size in 1 or 2 years whereas others

require 4 or 5 years.

FIGURE 33 —Size of jack pine can be regulated by age

class and time of seeding At left are 2 1-0 seedlings;

center 2 seedlings are 1)^-0 age; at right are 2 seedlings

of 2-0 age.

TABLE 21.-—Measurement ofjack pine and red pine stock from Lake States nurseries

Species and age class

Density

per square

foot

Length

Stem

caliper

Fresh weight Top-root

ratio by

weight

Trees

(years)

Top Root Top Root Total

measured

Jack pine:

K-0

1-0

1-0

l>^-0

2-0

2-0 _ -

Number

' 70

1 70

60

1 70

48

1 65

16

16

16

16

16

16

50

60

45

48

15

16

16

16

16

16

Inches

1. 2

2.8

4. 7

3.8

7.4

4. 0

3.6

5. 1

13. 7

7. 2

2. 2

1. 6

2.9

3.4

6.3

6. 6

4. 1

4.0

7.3

5. 1

6.9

8. 1

Inches

3. 5

6.4

9. 5

9.4

7. 1

8.6

10. 6

12. 1

11. 7

17.6

6. 1

10.4

7.9

10.4

9.3

9.4

10.6

10. 6

9. 6

11. 3

11.0

14. 0

}ii inch

2. 1

4.7

5.3

8.0

9.8

6.0

7.4

10.7

13. 8

12. 0

3. 6

7.0

5. 7

7.6

9. 6

7.3

9.4

9. 0

13.4

9. 0

11.8

13.3

Grams

0. 64

1.52

1. 95

4. 48

8. 24

2. 66

4. 24

10.47

19. 71

15.44

.42

1. 12

2. 63

3. 63

9.67

5.47

5. 91

5. 15

10. 90

10. 72

8. 24

20. 72

Grams

0.48

.57

.46

1.42

1.58

. 70

1.82

2. 85

3. 23

5.00

.26

.89

. 70

. 86

1.59

.83

2. 89

2. 23

7. 02

2. 23

3. 60

4. 99

Grams

1. 12

2. 09

2.41

5. 90

9. 82

3. 36

6.06

13. 32

22. 94

20. 44

. 68

2. 01

3.33

4.49

11. 26

6.30

8.80

7. 38

17.92

12.95

11.84

25.71

1. 33

2.67

4. 24

3. 15

5. 22

3.80

2.33

3. 67

6. 10

3.09

1. 62

1. 26

3. 76

4. 22

6. 08

6.59

2. 04

2. 31

1. 55

4.81

2.29

4. 15

Number

30

150

30

30

50

1-1 60

1-1 80

1-2

1-2

Red pine:

1-0 - -

10

50

10

1-1

2-0

50

80

2-0

3-0 _ _ - 250

3-0 ^ _ 30

2-1

2-1

2-1

1-2 - _-

60

160

30

50

3-1 „^_ --- 60

2-2 90

1 Estimated density.

56 Agriculture Handbook 110, U. S. Department of Agriculture
TABLE 22.—Measurement of white pine and white spruce stock from Lake States nurseries

Species and age class

(years)

Density Len gth

per square

foot

Top Root

Number Inches Inches

1 70 2.0 6.7

50 3.3 9. 0

16 3.6 11. 9

16 4. 4 10. 9

16 4. 7 10.5

16 7. 1 14.7

16 11. 5 14. 0

16 10.3 8. 1

16 15. 3 14. 7

1 80 1. 2 4.0

180 2.8 9. 6

1 70 4. 7 8. 0

30 6. 0 4.6

16 4.6 8.9

16 5. 9 11. 3

16 8. 1 5.9

16 6.4 9. 6

16 5. 5 9. 1

15 7.6 7.8

Fresh weight

Stem

caliper

Top Root Total

%4: inch Grams Grams Grayns

3. 3 0. 33 0. 34 0.67

6.0 1.07 . 66 1.73

6. 9 1. 74 1. 96 3.70

8. 1 2. 77 2.30 5.07

8. 7 3. 95 2. 58 6.53

9.7 5. 87 4.38 10. 25

14. 7 18. 59 8. 50 27. 09

12. 7 16. 09 7. 26 23.35

18. 7 38.57 16.80 55.37

1. 9 .09 . 09 . 18

4.0 .57 .35 .92

6. 4 2. 11 . 83 2. 94

11.8 9. 69 3. 28 12.97

4. 5 2. 54 2.00 4. 54

10. 4 7.46 3. 33 10. 79

13. 1 12. 82 4. 72 17.54

10. 5 3.77 2. 68 6. 45

9.0 3.43 2. 33 5. 76

16. 2 14. 56 8. 28 22.84

Top-root

ratio by

weight

Trees

measured

White pine:

1-0 _-

2-0

1-1

2-1

2-1

3-1

l-3___-_.

2-2

2-3

White spruce:

1-0

2-0

3-0

4-0

2-1

2-2

2-2

3-1

3-1

3-2

0.97

1. 62

. 89

1. 20

1. 53

1.34

2. 19

2. 22

2. 30

1. 00

1. 63

2. 54

2. 95

1. 27

2. 24

2. 72

1. 41

1.47

1. 76

Number

30

50

50

60

110

30

30

20

30

10

29Ö

160

80

80

80

20

80

50

30

Estimated density.

TABLE 23.—Measurement oj miscellaneous conifersfrom Lake States nurseries

Species and age class

Density

per square

foot

Length

Stem

caliper

Fresh weight Top-root

ratio by

weight

Trees

(years)

Top Root Top Root Total

measured

Black spruce:

2-0

Number

50

18

16

16

16

16

16

45

12

16

1 16

1 16

Inches

6. 7

10. 4

5. 6

7.2

IL 6

5. 1

5.5

3.0

7.3

6.8

5.0

6. 2

Inches

5. 9

9.3

9. 1

6.0

7. 5

10.6

10. 9

2. 7

10. 9

4.9

8. 9

7.0

>^4 inch

9. 2

14. 5

8.0

10. 9

17.6

7.0

n. 0

3. 1

13.4

6.9

7. 7

7. 7

Grams

6.44

13. 06

3.48

10. 64

32.03

4. 27

6. 57

7. 70

18.80

3. 84

5.48

1. 92

Grams

2. 63

7.06

2.70

4.42

8.41

1. 69

4.43

1. 90

6.40

2.33

2. 22

2.36

Grams

9.07

20. 12

6. 18

15. 06

40. 44

5. 96

IL 00

9. 60

25. 20

6. 17

7.70

4. 28

2.45

1. 85

L 29

2. 41

3. 81

2.53

L48

4.05

2. 94

1. 65

2.47

.81

Number

20

2-1

Norway spruce:

3-l__ _

30

50

3-2

2-4

Scotch pine:

2-1

2-1

White-cedar:

2-0

3-2

20

30

50

50

20

30

Hemlock:

3-1 Iß

Balsam fir:

2-2

Tamarack:

2-0

10

10

1 Estimated densitv.

Forest Nursery Practice in the Lake States 57
TABLE 24.—Measurement of broadleaf stock from Lake States nurseries

Species and age class

(years)

Sugar maple:

1-0

2-0

3-0

1-0 wildings

Yellow birch:

1-0

2-0

3-0

Red oak:

1-0

2-0

Basswood :

1-0

2-0

White ash:

1-0

2-0

Black ash:

1-0

Rock elm:

1-0

iH-o

2>^-0

Beech:

1-0

Density

per square

Leu gth

foot

Top Root

Number

115

10

1 10

15

Inches

3.3

3. 6

9. 6

2.0

Inches

6.0

10. 8

13. 2

3.3

1 15

17

1 15

3. 6

11. 4

20.5

6. 1

9.4

12. 6

1 10

1 10

3.8

7.9

11.4

13. 2

1 10

1 10

3. 2

5.8

8.5

9. 4

1 10

1 10

4.5

9. 7

9.7

10. 8

6 2.0 4.6

15

38

1 15

.9

4. 1

8.5

5.3

7. 9

8. 6

1 5 3.5 6.4

Stem

caliper

}^4 inch

6.3

10. 6

13. 7

4. 7

6.3

12. 5

18. 7

12. 1

13. 7

11. 7

17. 0

6.0

11. 9

5.3

3. 2

6. 5

13.4

6. 2

Fresh weight

Top

Grams

1. 09

. 52

2. 58

. 51

. 63

2. 68

14. 32

4. 26

3. 38

3. 19

3. 16

. 28

4. 95

. 10

. 60

1. 49

5. 32

1. 21

Root

Grams

1. 18

3. 60

6. 71

. 61

. 56

2. 71

9. 26

6. 34

14. 75

3. 73

15. 80

. 45

5. 97

. 59

.40

2. 34

10. 58

1. 54

Total

Grams

2. 27

4. 12

9. 29

1. 12

1. 19

5. 39

23. 58

10. 60

18. 13

6. 92

18. 96

. 73

10. 92

. 69

1.00

3. 83

15. 90

2. 75

Top-root

ratio by

weight

0. 92

. 14

.38

. 84

1. 12

. 99

1. 55

. 67

.23

.86

.20

. 62

,83

. 17

1. 50

. 64

.50

. 79

Trees

measured

Number

80

30

520

30

230

30

780

30

60

130

30

50

30

30

30

30

60

30

1 Estim_ated density.

58 Agriculture Handiooh 110^ ZJ, 8, Department of Agriculture
SEEDBED PREPARATION AND SOWING

The success of either broadcast or drill sowing

depends to some extent upon the thoroughness of

ground preparation. To obtain the good tilth

that is essential, the nurseryman must use proper

equipment and carefully plan and time the various

phases of the job. The equipment and its uses

are discussed in an earlier section (p. 33). All

ground preparation should be completed early

enough so that the soil can settle before sowing is

done.

Prospective nursery areas that support a soilimprovement crop require a slightly different

method of preparation than areas that are fallow.

If the nursery is to be seeded in the fall, the green

cover crop should be turned under early enough

so that it can decompose before seeding is begun.

Soil-improvement crops commonly sown in the fall

reach the optimum stage for turning under about

the middle of June or early July. Spring-sown

crops tend to mature later and do not require

turning down until about the last week in July.

After plowing, the area should be disked.

A seedbed surface as near level as possible facilitates a good job of sowing. Therefore, after

initial ground preparation, and when the seedbed

boards are in place or the sides of the beds delineated by wire, it is good practice to cut down the

high points in the beds and fill the depressions.

A bed leveler is useful for this purpose (fig. 34).

If a high water table exists in any part of the

nursery, or if there is a drainage problem, the beds

should be higher than the paths. Usually, the

weight of the tractors used in the nursery depresses

the paths sufficiently. If necessary, however, the

paths can be lowered easily and quickly with a

roundpoint shovel or corn tiller. Some nurserymen have found it convenient to shape the seedbeds with a special tool designed for this purpose

(fig. 35).

In fall seeding, seedbed boards are placed on

one side of the bed only to simplify rolling out the

screen or snow fence that is used to hold the mulch

in place over winter. The remaining bcdboards

are put up in the spring after the mulch has been

removed and the seeds start to germinate.

FIGURE 34.—A hand-drawn

bed leveler equally well

adapted for drill- or

broadcast-sown beds.

Forest Nursery Practice in tlie Luke states 59
FIGURE 35.—A seedbed shaper of commercial manufacture.

Drill seeding has quite generally replaced broadcast seeding by hand in Lake States nurseries.

Although it does not afford as uniform distribution

of seed per given area as does broadcasting, it is

the most economical method. It eliminates the

cost of sand covering and permits mechanical cultivation. However, opinion differs as to the relative merits of drill versus broadcast seeding. At

fairly high seedbed density (150 or more per square

foot), broadcasting probably consistently produces

slightly larger and more uniform stock with lower

cull percent. This is attributed to a better distribution of the plants over the entire growing space

and greater uniformity of depth of the sand cover.

But with the trend toward rather low seedling

density (often onh' 50 to 60 per square foot), there

is less advantage for the broadcasting. Turner

{178) found the average dry weight of 2-0 red pine

seedlings nearly the same in drill and broadcast

beds grown at rather low densities.

For many years conifers were sown in 10 drills

per 4-foot-wide bed with a space of 4.6 inches

between rows, center to center. In 1938, Lanquist

{79) introduced the 7-drill bed that left a 4^^-inch

space between outer edges of adjoining drills.

This made it easier to cultivate between the rows,

and with less damage to the trees, and also simplified vertical root pruning.

An experiment conducted at Hugo Sauer Nursery, Rhinelander, Wis., involving several methods

of seeding jack pine did not show any advantage

in first-year field survival of 2-0 stock for broadcast seeding over drills or bands. If anything,

the narrow drill seeding had some advantage, as

shown in the following tabulation:

Sprmg-planfed ^-0 jack pine

Method of sowing:

Broadcast

Do

Drills 1 inch wide, 4}^ inches

apart, center to center

Do

Drills 2 inches wide, 4}i inches

apart, center to center

Do

Bands 4 inches wide, 12 inches

apart, center to center

Do

Bands 16 inches wide, 12 inches

apart, center to center

Do

Least significant mean difference at 5-percent level

Least significant mean difference at 1-percent level

BROADCAST SEEDING

Where hand methods are used, the seed should

be measured out in small quantities and broadcast

by an experienced man. The smaller the uni.t

sown with each measure of seed, the more even will

be the distribution; 100-square-foot units are a

convenient size. A graduated container facilitates

rapid handling of the seed. The sower carries the

Trees per

square foot

{number)

40

80

Field

(pe-i

survival

rcent)

88. 8

83. 2

40

80

96.0

93. 8

40

80

96.8

91. 5

40

80

90. 5

81. 1

40

80

91. 2

81. 2

7. 80

10.37

60 Agriculture Handbook IJO, U. S. Department of Agriculture
seed in a pail and scatters them from the margin

to the center of the bed with his free hand as he

moves along the path.

Broadcast seeding by mechanical methods is

preferred by some nurserymen. Manually operated lawn seeders equipped with hopper and

slotted bottom have proved satisfactory for this

purpose. The Nekoosa-Edwards Paper Company

Nursery, Port Edwards, Wis., uses a Scott lawn

seeder that is about 18 inches wide. The seeder

is run with 1 wheel on top of a vertically set 1- by

4-inch bedboard placed on two sides of the bed.

A trip is made down one side of the bed and back

on the other. This leaves an unseeded strip about

10 inches wide down the middle of each bed. The

strip, to a large extent, does away with the depression of growth often found in densely sown beds

that are broadcast to their full 4-foot width.

The mechanical seed drill (fig. 13, p. 34) can also

be adapted for broadcast seeding by removing the

seeder assemblies and replacing them with a baffleboard on which the seed strikes as it falls to the

ground.^^ The baffleboard is mounted at an angle

to the surface of the bed with the tubes directly

above it. Since the direct-force feed device can

be regulated to deliver a constant and uniform

flow of seed, distribution is better than that

ordinarily obtained by hand methods.

When seed are sown broadcast, either by hand

or mechanically, they must be pressed lightly

into the soil with a roller and covered with ji to

% inch of nonalkaline sand.^^ The sand can be

applied by sifting it through a tray that has a

bottom ot 4-mesh hardware cloth. Two men,

facing each other across the seedbed, hold the

handle-equipped tray. A third man shovels the

sand into the screen. The screened part of such a

tray is usually 40 inches long by 30 inches wide with

handles 12 inches long. On larger operations, a

special sanding machine can be used which carries

the sand on an endless belt device similar to that

on a manure spreader.

At the Bessey Nursery, Halsey, Nebr., a handdrawn sand spreader was devised which in

appearance is like a medium-sized lime spreader;

it consists of a trough the width of a bed mounted

on two wheels. An adjustable, rotating, vaneequipped shaft in the bottom of the trough pushes

out a uniform layer of sand onto the bed. Great

care should be taken to use lime-free sands, because

limy sands can cause much damping-off and retard

growth, especially of the pines grown in Lake

States nurseries (38). If lime-free sand is not

avaüable, burlap mulch or sawdust may be used

to cover broadcast-sown seed.

13 A blueprint of the Bessey Nursery seed sower can be

obtained from U. S. Forest Service, Federal Center, Bldg.

85, Denver 7, Colo.

1^ Seeds of a few species, notably aspen and cottonwood

(19), are sown directly on the surface and not covered.

For the first 2 or 3 days the beds are watered several times

daily to keep the surface continually moist. Seeding on a

}^-inch layer of screened peat aids germination because of

retention of moisture.

Forest Nursery Practice in the Lahe States

408189°—57 5

DRILL SEEDING

When a mechanical seed drill is used, the

nurseryman should make sure that it is adjusted

to deliver the proper amount of seed per unit of

seedbed. A simple method for adjusting the

machine is to place a wide piece of canvas on the

ground and operate the seeder over it. Changing

sprockets on the feed and drive shafts will cause

different amounts of seed to be delivered. The

seed falling onto the canvas at each trial should

be accurately weighed or counted to check delivery

rate, and the testing continued until the right

combination of sprockets is found. Since the

drill seeder is equipped with a device for covering

the seed and also with a roller that compacts the

soil, the need for applying sand and then rolling

the beds is eliminated.

Beds with hand-sown drills must be floated to

cover the seed and then rolled to firm the soil.

In long, continuous beds, the drills usually are

made lengthwise to facilitate later mechanical

operations. However, crosswise drills are appropriate to 4- by 12-foot seedbeds, and a drill board

is a useful tool for their preparation. It can be

made by tacking wood strips of the desired width

and thickness, 4K inches apart, onto a 20- by 46-

inch board.

Seeds that are large or diflicult to de-wing

usually are sown by hand in shallow drills. The

sower should measure and distribute them with

the same care that is required in handling smaller

or de-winged seeds. A semimechanical method

for handling seed of any size and shape, which is

much faster than the usual method of hand sowing, was developed by nurserymen of the Prairie

States Forestry Project (^7). Two to four men

ride a sled-type furrowing device and distribute

the seed by hand in drills as the machine is drawn

over the prepared bed.

DENSITY OF SEEDING

Since it is the general aim to produce a maximum

number of premium-grade trees per unit of seedbed

area, optimum density should be determined for

each species, taking into consideration the age at

which the stock is to be removed from the beds

and the purpose for which it is to be used. A

better quality of plant is required for outplanting

as seedlings than for transplanting in the nursery.

Although top and root length must be considered

in evaluating the quality of seedlings, stem diameter is the most useful criterion. This latter

characteristic usually is influenced by density

more than by other factors. Recommended

seedbed densities for conifer and hardwood stock

are given in table 25.

The changes adopted in seeding densities in

recent years reduced by about half the densities

used several decades ago. This reduction was

especially necessary for field planting stock because

high densities result in smafl-caliper, spindly, and,

61
on occasion, topheavy stock that is easily matted

down. The root systems of such trees often are

undersized and in periods of drought are unable to

supply enough moisture to keep the plant alive.

Furthermore, in high-density beds, trees of inferior

genetic quality are more difficult to grade out

than they are in medium- or low-density beds

where the contrast in size is more apparent.

TABLE 25.—Recommended seedbed density per

square foot, by species, for stock that is to be field

planted or transplanted in nursery ^

Species

Density when stock

for field planting

is—

Density when

stock for transplanting is—

1-0 iK-0 2-0 3-0 1-0 2-0 3-0

Douglas-fir _ _ _

No. No. No.

30

50

No.

40

40

No. No.

75

75

65

No.

75

Fir, balsam 75

Hemlock, eastern 65

Larch, European 40

50

50

50

50

50

50

30

50

40

"40"

"4Ö"

30

40

60

65

65

65

65

65

65

50

"6Ö'

Pine, Austrian

Pine,jack 55 50 65

65

65

65

65

45

75

Pine, ponderosa

Pine, red _ __

Pine, Scotch. _

Pine, white _

Redcedar, eastern

Spruce, black, blue,

Norway, white,

and western white 75

Tamarack

White-cedar, northern* 65

25

25

65

Ash, black, green,

and white _ 15

15

15 15

25

Basswood _ _ _ 25

Birch, paper and

yellow

Cottonwood 10

15

25

Locust, black 15 20

15

10

Maple, red, silver,

and sugar

Oak red and white 10

1 Since permissible densities are affected by soil-fertility

level, length of growing season, and frequency of watering,

the figures given here might be raised by 20 or 30 percent

under exceptionally favorable conditions.

The chief reason for using lower seedbed

densities for stock to be transplanted in the nursery

is to reduce cull percent not only in the stock to

be transplanted, but also in the transplants

themselves. The latter point is of especial moment

in the case of 2-1 transplants. Since they are left

in the transplant bed only 1 year, fairly good-sized

2-0 stock is necessary if an adequate size transplant is to be produced. With 2-2 conifer stock,

there can be much more tolerance of higher seedbed densities because deficiencies in the 2-0 size

usually are made up by the time the plants have

completed 2 full years in the transplant bed.

In a number of experiments, the general trend

in response of trees to increasing density of stand

62

was a marked and consistent decrease in average

stem diameter and a decrease in average total

weight per tree (table 26). For white pine grown

at densities of 20 to 80 per square foot, there was

roughly a decrease of 0.5 gram in average total

fresh weight per seedling for every increase of 10

in density. Quadrupling density from 20 to 80

per square foot resulted roughly in reducing by

half the average green weight per plant. For a

somewhat faster growing species, such as red pine,

the average green weight was reduced by nearly

60 percent by a density increase from 20 to 80.

For sugar maple, the quadrupling of density from

around 5 to 20 per square foot resulted in about

a 70-percent reduction in average seedling weight.

For hardwoods in general, there is a more marked

reduction in tree height as density increases than

there is in conifers. Increased densities in 3-0

conifer beds tend to increase the ratio of top to

root on a weight basis.

Red pine 3-0 stock is quite satisfactory for

spring planting if grown at a density t>f 40 to 50

per square foot, and it is becoming a favored

stock for use in machine planting. In a spring

planting, stock grown at about 45 trees per square

foot showed less than 5 percent first-year mortality

in the field. Mortality in fall-planted stock

doubled when the density in the beds was increased from 25 to 80 trees per square foot. In

the former, mortality was 25 percent; in the latter

it was 50 percent. These differences are highly

significant. Densities in 3-0 red pine beds may

be considerably higher if the stock is to be planted

in the spring than if it is to be planted in the fall.

A separate experiment with stock from a different nursery, and planted on a different forest,

brought out the general superiority of 2-1 transplants of red pine over 3-0 seedlings for fall

planting. First-year survival of the transplants

was 93.2. For the 3-0 red pine seedlings grown

at nursery densities of 15, 33, 48, 75, 84, and 101

per square foot, the first-year field survivals were

80, 53, 61, 52, 46, and 51 percent, respectively.

These differences are highly significant statistically

in favor of the lowest density class.

The 2-0 class of white pine stock is seldom

suitable for field planting regardless of the density

at which it is produced. 2-0 stock grown at

densities of 60 to 70 seedlings per square foot

produces a maximum number of plants for transplanting. If grown at densities of 40 to 45 plants

per square foot, well-balanced 3-0 can be produced

without top and root pruning. For fall planting,

somewhat lower densities, preferably 25 to 35

seedlings per square foot, are required for 3-0 white

pine to yield good survival.

In an experiment on white pine, 3-0 stock grown

at 26 trees per square foot gave 89 percent secondyear survival in fall plantings, or nearly as good as

2-1 transplants which had 91 percent survival.

In spring plantings, first-year survivals of more

than 90 percent were obtained with stock grown

as dense as 50 trees per square foot.

Agriculture llandhook 110^ Ü. S. Department of Agriculture
TABLE 26.—Eßect of density oj seedling stand on size of stock

Class of stock and

Actual

density

per square

foot

Average length Average

stem

diameter

Average green weight Average

top-root

species 1

Top Root Top Root Total

ratio

2-0 jack pine

Do

Number

18

29

49

59

74

13

26

47

59

81

15

33

48

75

84

101

3

8

11

20

Inches

6.4

7.2

5.8

5. 1

5. 1

3.4

4. 1

4.9

4. 5

5.0

7.3

6. 6

6. 6

6.3

5.9

6. 6

14.4

11.2

9. 2

7. 6

Inches

7.8

7. 8

8. 4

7. 9

7.5

12. 2

10. 7

10. 4

10. 2

9. 8

11.8

10.3

9.4

9. 7

9.4

8.6

14. 7

12. 7

12. 5

11. 1

}U inch

11. 4

9.8

8.4

7. 8

7.4

8.0

7.4

6.8

6. 3

6.0

11. 1

8.3

7.3

7. 4

6. 8

6. 7

17.8

14. 9

13.4

12.8

Grams

10. 40

7. 30

5.30

4. 10

3.80

4. 73

4. 68

3. 70

2.85

2. 78

14.51

8.01

5. 47

5.25

4. 70

4. 30

5.81

3.28

2.88

1. 84

Grains

1. 90

1. 40

1.00

. 80

.80

1.97

1.54

1.07

.89

. 74

2.62

1. 29

. 83

. 83

. 78

.66

14. 79

8. 21

6. 74

3. 74

Grams

12.30

8. 70

6.30

4.90

4. 60

6. 70

6.22

4. 77

3. 74

3.52

17. 13

9. 30

6. 30

6.08

5. 48

4. 96

20.60

11. 49

9. 62

5. 58

5. 47

5.21

Do

Do --

Do

5.30

5. 12

4. 75

3-0 white pine

Do

2.40

3.04

Do 3.46

Do

Do

3-0 red pine

Do

3.20

3.76

5. 54

6. 21

Do 6.59

Do 6.33

Do 6.03

Do 6. 52

3-0 sugar maple

Do _ _ __

.39

. 40

Do .43

Do .49

1 Jack pine and sugar maple grown at the Hugo Sauer Nursery, Rhinelander, Wis. White pine and red pine stock

grown at the Hayward Nursery, Hayward, Wis.

A series of 5 separate experiments, each involving nearly 10 thousand 3-0 red and white pine

trees, showed highly significant différences in

survival, in each case in favor of trees grown at

low density compared with high density. The

density markedly affected diameter and, to some

extent, top-root ratios as shown in table 26 for

3-0 age classes.

With 2-0 jack pine, no significant difference was

observable in field survival in two separate tests

involving thin and moderate sowing. A poor firstyear survival of 56 percent was noted in fallplanted 2-0 jack pine. These seedlings were

grown on soil that had an excessively high fertility level which resulted in unusually tall, heavy

foliaged trees with tops averaging more than 8

inches. The top-root ratio was 5.3 to 1 on the

basis of fresh weight. Other age classes of better

balanced stock had a first-year survival of 82 to

94 percent. The same general trend of poor

survival in fall planting held for poorly balanced

3-0 red pine when compared with other classes of

stock that had a better relation of tops to roots

(160).

COMPUTING THE AMOUNT OF

SEED TO SOW

Accurate information should be available regarding the germination percent and total number of

seed per pound for each lot of seed to be used.

This information, and the desired density per unit

of area, can be used to compute the amount of

seed to sow. The formula follows:

Forest Nursery Practice in the Lake States

P= AXD

GXSXY' when P== pounds of seed; A=

area in square feet; Z>== density, that is, desired

number of seedlings per square foot; 6^germination percentage of the seed, expressed as a decimal;

5=number of seed per pound as they come from

the container; and F=survival factor, variable

by species, based on the percentage of viable seed

that will produce seedlings which survive at end

of the first year, expressed as a decimal.

For example, suppose that the amount of red

pine seed to sow per 100 square feet to produce 55

seedlings per square foot is to be determined.

The seed to be used run 45,000 to the pound, have

a germination of 90 percent, and a survival factor

of 0.65. The formula becomes:

100X55

0.90X45,000X0.65

P-= 0.209 pounds

The number of seed to sow per linear foot of

drill can likewise be computed. The formula

follows:

N= D

GY'

when AT'^number of seed to sow per linear foot;

Z>===desired stand per linear foot; ff=germination

percentage of the seed, expressed as a decimal

fraction; and F=survival factor, based on the

percentage of viable seed that will produce seedlings which survive at the end of the first year,

expressed as a decimal.

63
Por example, if the desired stand is 10 seedlings

per linear foot, and the seed has a germination

percentage of 60 and a survival factor of 40 percent, the formula becomes:

^r^ 10

0.60X0.40' ^^

AT^ 41.67 seed per linear foot of drill.

The following tabulation may be useful to

nurserymen in judging roughly how much seed

must be sown to meet certain production goals, or

in gaging how much seed to sow in the absence of a

germination test. It is based on experience

tables for the more important species grown in

the Lake States.

Trees produced

per pound of

seed of average ge'rminaö^^„. „. tion capacity

bpecies. (thousands)

Douglas-fir 11. 00

Fir, balsam 8. 20

Hemlock, eastern ^ 24. 00

Larch, European 10. 80

Pine, Austrian 9. 10

Pine, jack 38. 00

Pine, ponderosa 4. 80

Pine, red 28. 00

Pine, Scotch 19. 00

Pine, white 11. 00

Redcedar, eastern 3. 80

Spruce, black 50. 00

Spruce, Norway 16. 00

Spruce, white 43. 00

Tamarack 60. 00

White-cedar, northern 12. 00

Ash, black 1. 20

Ash, green 4. 70

Ash, white 3. 10

Aspen, quaking 36. 00

Basswood . 30

Beech, American .80

Birch, paper 25. 00

Birch, yellow 9. 20

Cherry, black 1. 20

Cottonwood 25. 00

Elm, American 5. 50

Elm, rock 1. 90

Locust, black 6. 40

Maple, red 4. 20

Maple, silver . 34

Maple, sugar 1. 20

Oak, red . 07

Oak, white . 10

Walnut, black . 04

In every lot of seedlings, and to a minor extent

in transplants, there are cull trees that must be

discarded. Generally, from 5 to 20 percent of the

seedlings and 1 to 3 percent of the transplants are

culls. Cull percent varies by density of sowing,

soil fertility, class of stock produced, and rigidity

of culling standards. To compensate for expected

cull, an additional area should be seeded.

DEPTH OF SEEDING

Since depth of seeding influences the establishment of an even and uniform stand of seedlings,

its importance cannot be emphasized too strongly.

Each species has an optimum seeding depth that

64

varies with the size of seed, soil texture, and the

season of sowing (18, 174)- Although large seeds

may be sown more deeply than small seeds, deep

sowing increases the liability of injury from

damping-off fungi, and makes emergence more

difl5cult. Seeding depth can be about one-third

greater in the light, sandy soils than in the heavier,

loam soils because of the comparatively greater

ease of emergence in the former. Experience has

also shown that in the fall seeds should be sown

slightly deeper than in the spring to prevent their

being thrown out by frost action or uncovered by

wind erosion.

TIME OF SOWING

Since seed dormancy and optimum germination

temperature vary by species, the time of sowing to

assure prompt and complete germination also

varies. In general, seed of the conifers commonly

produced in the Lake States can be safely and often

advantageously sown in the fall. When sown in

the spring, seeds of some species require pretreatment for best results. Stratification for 30 to 60

days of 40° F. has proved to be a good method for

breaking embryo dormancy of several species.

Seeds that do not keep well in storage, or those

that can germinate within a few days after they

ripen, should be sown immediately after collection.

Silver maple and white oak seeds are in this

category.

Local climatic conditions must be taken into

account in setting up seeding practices, particularly those for fall sowing. While fall sowing in

the Lake States region should be done during late

September or October, injury and losses from premature germination may result if temperatures

are unseasonably warm. Therefore, at nurseries

in areas where fall weather conditions are variable,

seeding should be postponed until temperatures

conducive to premature germination have passed.

Premature germination of fall-sown seed, with

subsequent freezing and mortality, apparently is

mostlikely to occur in the more southerly nurseries

in the Lake and Central States. This is particularly true of nurseries in a latitude of about 44°

or farther south, or where the frost-free period is

140 days or more. For example, Chittenden Nursery reports that jack pine has, on occasion, tended

to germinate prematurely; hence, sowing there is

delayed until late in October. Fall germination of

ponderosa pine, Scotch pine, and Norway spruce

has also been reported.

Fall-sown seedlings commonly are larger and

better developed at the end of the first season

than spring-sown seedlings, because of the longer

growing season available to them. For instance,

in a lot of 2-0 jack pine grown at the Hugo Sauer

Nursery, Rhinelander, Wis., the average fresh

weight per fall-sown seedling was 8.2 grams as

compared to 5.3 grams per spring-sown seedling.

Second-year red pine often shows the same general

relationship.

Agriculture Handbook 110^ Ü, S. Department of Agriculture
Because fall-sown beds must be protected from

seed-eating birds and rodents, wind erosion, and

frost heaving, the cost of completing the work, per

square foot of seedbed, is slightly higher than for

spring sowing. However, because of more complete germination, better development, and a

higher percentage of plantable trees obtained from

fall sowing, the unit cost per thousand plantable

trees normally is less than for spring sowing.

Spring seeding should be done as early as the

ground can be worked. Early seeding gives the

young plants the advantage of a longer growing

season, an important factor in the development

of conifer seedlings.

In producing 1^-0 stock in the Lake States,

seeding must be postponed until June 10 to 15,

which allows only a short growing season the first

year. Sowing at this late date exposes the seedlings to high air and ground temperatures during

the period of germination and frequently results

in high, early mortality. The remaining stand also

is subject to heavy loss over winter by frost heaving and winter injury. Nevertheless, late spring

sowing for the production of 1)^-0 jack pine has

been successful. Because of its better top-root

ratio, this class of stock sometimes has been used

in preference to 2-0 unpruned jack pine. However, since a very satisfactory type of seedling for

field planting can be obtained by top-pruning 2-0

jack pine, the practice of raising 1^-0 stock is

recommended only in case of emergency where

fall or early spring seeding cannot be accomplished.

The general practices relative to season of sowing discussed here for conifers also are applicable

to the hardwoods. Although the seeds for many

of the species whose fruits ripen in the fall can be

stored over winter and seeded in the spring, fall

seeding or stratification of the seed over winter has

given better results than sowing unstratified seed

in the spring.

SEEDBED MULCHES

Mulches generally are used to protect newly

sown seedbeds from wind erosion, frost heaving,

and premature germination in the spring, and to

conserve moisture. Frequently mulches also are

used to protect spruce, white-cedar, and other

slow-growing species during the first winter following germination. Mulches also offer some control

against pilfering of the seeds by birds, and retard

weed growth during the pregermination period.

Several materials, including burlap, light woven

cotton cloth, straw, marsh hay, and sawdust, have

been used for this purpose. Each nurseryman

should decide from his own experience whether the

benefits obtained from using a mulch more than

offset the cost of the material and labor.

Burlap or cotton cloth strips, wide enough to

cover the beds and fastened with wire pins 4 to 6

feet apart, are the most desirable mulches for

spring-sown beds. Although initial cost and a

relatively short life are objectionable features,

ForeM Nursery Practice in the Lake States

these materials can be applied and removed at a

mmimum labor cost. Since excessive moisture

and contact with the soil tend to hasten their

disintegration, they are not particularly satisfactory as overwinter i^ulches. To extend their

Hfe, it is highly important that they be thoroughly

dry before they are rolled and stored (fig. 36).

Southern nurseries have been treating burlap with

copper naphthenate to improve resistance against

rotting {183).

Clean straw and marsh hay with a high percentage of sedge have proved satisfactory for protecting fall-sown beds. They are much cheaper

than burlap and can be applied at a reasonable

cost if the work involved is adequately organized.

Material free of weed seeds should be used. It

can be obtained by cutting and gathering the hay

when its seed is in the milk stage and the crop is

immature. Rye straw has also proved to be a

good mulch material in Forest Service nurseries.

Its long stems, large yield per acre, and the fact

that it is ready for cutting at an early date makes

rye a very desirable crop to produce for a mulch.

If properly handled, it can be used several years.

When removed from the beds in the spring, it

should be stacked in a pile where it can be kept

dry.

In Lake States nurseries, a layer of straw K to 1

inch deep when compressed has been found to be

sufiacient for mulching newly prepared seedbeds.

A shghtly deeper layer is required for 1-0 stock

since the purpose here is to reduce as much as

possible the alternate freezing and thawing of the

soil, the action of which heaves the small seedlings

out of the ground. The mulch is spread on the

beds from a small moving trailer that straddles

the beds. Two to four men working from the

FRAME MADE OF 1-INCH

LUMBER EXCEPT FOR 2-

INCH TRIANGULAR CORNER

BLOCKS "A"

FIGURE 36.- -A reel is an efficient tool for rolling and

Kstoring burlap.

65
paths shake out the material and spread it by

hand as evenly as possible. After the mulch has

been spread, hardware cloth or snow fence is rolled

out over it to hold it in place (fig. 37). Where it

is necessary to mulch 1-0 stock, one edge of the

cloth or snow fence is rested on the seedbed board

to provide aeration and prevent compaction of

the mulch under weight of snow.

Other organic middies, including hardwood

leaves and pine needles, have proved effective at

some nurseries. Because these materials usually

are expensive to collect and difficult to remove

from the beds in the spring, they are not used as

extensively as straw mulches. Furthermore, there

is risk of bringing in needle blight. Softwood and

hardwood sawdust have also been used to a

limited extent, but this type of mulch is difficult

to remove in the spring and, because of the quantities required, cannot safely be left on the bed

during the period of germination and early seedling

development.

Mulches delay germination for 10 to 14 days.

Hence, they may be useful in retarding too early

germination in sections where unseasonable warm

spells frequently occur. The removal of mulches

is discussed on ]). 71.

Some nurserymen have found that a snow

blanket obtained with a series of snow fences is

very efl^ective in protecting seedlings. It reduces

soil erosion from wind action and the accumulated

snow is an additional source of moisture. Labor

costs for this method are ordinarily less than for

midching.

FIGURE 37.—Rolling out hardware cloth to hold mulch

in place on recently seeded beds.

66 AgricuUiire Handbook HO, U. S. Department of .[¡/rimiltiire
SOIL MOISTURE AND IRRIGATION

Every soil has a maximum water-holding capacity. This field capacity usually is from 12 to

15 percent for loamy sand soils containing 15 to 20

percent of silt-plus-clay; the water applied to the

root zone (usually the surface 8 inches) should

bring the moisture content up to about field

capacity. Application of more water merely

results in loss by percolation and is hence a waste

of power in applying .the excess.

Together, percolation, evaporation, and plant

use often cause a rapid loss of water from the soil

surface (fig. 38). In one instance there was a drop

from 23 percent total moisture directly after a rain

ending at 8 a. m. to about 15 percent in a brief

period of 6 hours (fig. 38). Thereafter, it leveled

off at about 14.5 percent by 8 a. m. the following

day. This value apparently is the approximate

field capacity for this type of soil. Similar results

were noted by Turner (176) in the Beal Nursery

at East Tawas, Mich.

During the germination period, and for about

2 months thereafter, irrigation is necessary in Lake

States nurseries, particularly for conifer seedbeds.

The critical surface inch of soil must be kept moist

by daily watering or rain, except in days of low

evaporation. In periods of extreme heat or

drought, especially in June and July, or when

strong drying winds result in sand blowing, two

waterings a day may be needed in order to avoid

tremendous losses. Considerable supplemental

moisture also must be supplied to seedbeds older

than 2 months.

Properly watered stock will be larger and more

vigorous than unwatered stock. However, no

rigid rule can be prescribed as to frequency of

watering. It will depend on rainfall, air temperatures, humidity, and the tree species and its

stage of development. For seedbeds at the

critical germination stage, it is safer to overdo the

watering, perhaps wasting some, than to use too

little and risk the loss of part of the stand. Once

the trees are past the succulent stage, 1 or 2

waterings a week are usually adequate for seedbeds. At this stage, it is satisfactory to maintain

the available soil moisture at 4 to 8 percent for

the top 8 inches in jack and red pine beds, and at

5 to 10 percent in beds of white pine, spruces, and

hardwoods. One watering every week or 10 days

usually suffices for transplants. Although transplant beds do not require as frequent watering as

seedbeds, larger amounts are needed in a single

watering.

Records of the Hugo Sauer Nursery, Rhinelander, Wis., illustrate the use of water at a

typical Lake States nursery. In 1937 and 1938,

3,798,000 and 2,231,000 gallons of water, respectively, were applied to some 30 net acres of producing seed and transplant beds. May to SepForest Nursery Practice in the Lake States

)-* ~^8 A.M. (AFTER RAIN)

1 1 1

\

V ^^,.,_—12 NOON

^ ^^^ P. M.

^Q A.

Su

M. ^

\

12 NOON'' k TIME IN HOURS

FIGURE 38.—The drop in soil moisture content in a loamy

sand nursery soil is very rapid after a rain. The drain

of soil moisture by transpiration and evaporation is at

a minimum at night.

tember rainfalls for the 2 years were 12.3 and 24.8

inches, respectively, the former representing a

drought season (62 percent of normal rainfall)

and the latter a favorable season (127 percent of

normal rainfall). This nursery is located in an

area with a normal precipitation of 30.9 inches,

of which about 70 percent falls from April to

September, inclusive. Water was furnished by

three 200-gallon centrifugal pumps whenever total

soil moisture dropped below about 8 percent

(equivalent to 4 percent available moisture).

The irrigation record showed that the water

supplied in. the dry season ranged from 4.0 to 9.1

inches depending on class of stock, while in a

season of above-normal rainfall it varied from 0.1

to 3.4 inches (table 27). Although 70 percent

more irrigation water was required in 1937 than

in 1938, even the latter season of above-normal

rainfall required 21 waterings on first-year seedbeds. This was necessary because the rapid

drying of the surface of sandy soil hampers

germination.

While overhead irrigation systems generally

give excellent coverage, on occasion it may be

necessary to water the ends of beds with a hose

if winds carry the spray away from them. Snow

fences or windbreaks also have an effect on water

distribution. Rindt {124) observed that snow

fence on pipe supports had some tendency to

intercept water, and that in drought years firstyear seedlings in the beds adjacent to them sometimes suffered mortality.

67
TABLE 27.—Irrigation record for May-September in two successive years, Hugo Sauer Nursery,

Rhinelander, Wis.

Class of stock

1937 (dry season)

Waterings

Irrigation

water

applied

Total water

received ^

1938 (season of abundant rain)

Waterings

Irrigation

water

applied

Total water

received ^

First-year conifer seedlings

Second-year conifer seedlings. __

First-year conifer transplants.-.

Second-year conifer transplants

First-year broadleaf seedlings. _

Number

29

19

21

9

15

Inches

9. 1

5.8

6.5

4. 0

4.4

Inches

21.4

18. 1

18.8

16^3

16. 7

Number

21

14

12

Inches

3.4

2. 2

1. 9

1. 3

. 1

Inches

28. 2

27.0

26. 7

26. 1

24. 9

1 Including 12.3 inches of natural precipitation.

2 Including 24.8 inches of natural precipitation.

METHODS FOR MEASURING SOIL a more accurate determination can be made by

IvromTTTRF direct observation of the moisture content left m

IVlüliM Urvríi dried-down, well-rooted potted plants at time of

K T^- *T.i'^9''\''^?°^r? '"l''-'^^7v,^'^'?ïw"J ^'^2^Emporation method.-This method is faster beds and the 2- to 8-inch levels m the interior of the ovendry method and is well adapted to

second- or third-year seedbeds or transplant beds ^^ -^^^.^^ containing comparatively

must be kept quite moist This is Particularly J ^^^^ ^f ^^ ^^^^^^ It consists of

true m periods of extreme drought or heat when ^ ë^j^ ^^^ ^^ ^^ .^ ^ ^^^^^^_

the evaporation rate is so high that there may be bottom metal container set in a metal cap ; alcohol

little or no penetration of moisture below the ^ .^ ^^^ ignited to drive

surface inch or two m spite of considerable water- ^moisture (l^). The sample is then remg Patches of seedlmgs may die out for lack of available moisture content comLrstaSu^ïriQïeTots^^^^^ ^4%'^ ^'^ '^^"^^^^ ^^^^^ ^^^ ^'^ °^^^'^^

Sou moisture content can be determmed by any ^^ ?,¿ method.-This is a simple and

one of the methods described m the fohowing J^^ ^ » .^ i^^,, ^^ ^ ^^^^^^

paragraphs. It is also possible wi h a Ittle porcelain cone about 3 inches long with

training, for the nurseryman to estimate moisture Jabsorptive surface of 12 square centimeters

content withm a few percent, especially m the ^^^^_ ^^^ p^.^^^ ^^^ ^^^^ .^^^^ ^^^^ ^^ ^^^j.

critical, drier range. calcium chloride; then the open end is plugged with 1. Ovendry method.^k soil auger or tube is used ' .^^^¿^^^ .^ ^j^^ ^^g ^^ ^^^

to collect a soil sample from the bed The sample ^ ^ ^j ^ . j^ ^^

IS then placed in a ight can weighed dried in ^ ^.J ^¿^ ^^^ ^^^ ^^^^^^^ 1^^^^ ^^ ^

oven for 12 to 24 hours at 105 C then reweighed. tight lid, and reweighed. Available

Total moisture is computed by the foUowmg for- ^^.^^^^^ .^ ^^|^ computed.

Vr>^: 1 • j, • + In a trial at the Hugo Sauer Nursery, Khine- Total moisture m percent= ^^^¿^^^ ^.^^ .^ ^^^ ^^^^^ ^j^^^ ^^¿^^ 3 ¿o'nditions

(Fresh weight of soil) -(Ovendry weight of soil) ^^ 100 of total moisture described as moist (13.5 percent),

Ovendry weight of soil 1 ^^^^^ (9.5 percent), and dry (6.0 percent), the

Available moisture can be determined by sub- amount of water absorbed per cone was 2.0, 1.0,

tracting the wilting coefficient of the soil from the ^^¿^ g.l grams respectively {152). Since the

total moisture. Typical wilting points of soils over lilting coefficient of the soil was approximately 4

a range of textures are as follows: percent, the available soil moisture for these 3

Total silt-plus- computeiwiit- conditions was 9.5, 5.5, and 2.0 percent respecclay content mg coefßaenf . ' '

Texture (percent) (percent) tively.

Sand 9.4 2.2 ^ Tensiometers {127, 157).—A tensiometer conSand^Cms":::::::::::::::::: à.l 7:7 slsts of a porous day element attached to a

Silt loam-_.!!I___'-! 65.6 10.4 mercury manometer or dial gage indicator.

Although a fairly close approximation of the The porous clay element is placed in the soil at a

wilting coefficient is obtained from the formula depth where moisture status is desired, and the

Moisture equivalent system is fiUed with cooled water that has been

Wilting point in percent= ^-^ . boiled to remove air.

ßg AgriovUure Hmid'booh 110, U. S. Department of Agriculture
Compact, sturdy tensiometers cost approximately $22 and have given good service in the

field. The 6- and 124nch models are best adapted

to forest nurseries. They have a graduated scale

of 0 to 100 to indicate relative state of soil dryness,

the ^'100^' representing 1 atmosphere or 76 centimeters of mercury suction pull of the soil. Appropriate parts of the scale are labeled wet, medium,

or dry. When the needle enters the dry range,

irrigation is recommended.

Tensiometers do not work well when suction

pull exceeds about 60 centimeters of mercury

because air bubbles get into the system; however,

in sandy forest nursery soil the suction pull will

generally be in the range of 10 to 35 centimeters.

Some unavoidable fluctuations in readings occur

due to daily changes in temperature (58), but these

can be ignored.

With some experience in the use of tensiometers,

nurserymen will probably find them to be a useful

guide to prevent overwatering. Likewise, this

instrument may furnish some warning as to the

need of watering, particularly for fairly wellestablished plants with at least 4-inch roots. It

is less likely to be a reliable guide to watering

needs in newly germinating seedbeds that must be

kept quite moist at the surface. This is because

it is difficult, if not almost impossible, to measure

instrumentally the moisture content of surface

layers of soil only ji- to %-inch thick.

^ The relation of tensiometer readings to comparative status of soil moisture as read on one of the

instruments in commercial production is as follows

for the general run of crops and soils :

Scale reading in Equivalent in

terms of atmos- terms of centiSoil moisture pheres ofsuction meters of merstatus pull cury

Wet 0-0.30

Remarks

0-22. 8 Adequate to

abundant

moisture.

Medium__ 0. 30-0. 70 22. 8-53. 2 Usually adequate.

Very sandv soils

may requirp

irrigation.

Dry . 70-1. 00 53. 2-76. 0 Requires irrigation.

5. Electrical resistance method {15, 16, 109).—

This method is well adapted to soils with average

salt content. It consists of burying a special

plaster of Paris block or Fiberglas unit in the soil

at a desired depth (usually 2 to 3 inches for firstyear seedlings, and 6 inches for older trees) and

measuring the electrical resistance with a meter

that costs about $75. With the plaster of Paris

block a resistance of 2,800 ohms or more indicates

that the soil will shortly require irrigation to

bring it to optimum growing condition. The

need for irrigation is shown directly on the dial

of the meter in terms of relative soil moisture

conditions, 100 representing a fully saturated

soil. Irrigation is recommended when the meter

readings drop below 50 {16).

A half dozen blocks, each buried in large units

where class of stock or soil conditions are repreForest Nursery Practice in the Lake States

sentative, will give good coverage of the moisture

conditions in an average nursery and warn of need

of irrigation. ^ The Klocks can be left buried in

place with their lead wires placed on permanently

marked stakes so that workmen will not damage

the block or its leads with tools or machinery.

The meter itself can be quickly attached to the

leads, a reading taken, and then moved to the

next moisture station.

For very precise work in soil moisture determination, a moisture bridge costing about $165 is

recommended {15), along with a nylon resistance

unit in place of the plaster of Paris block. Some

investigators prefer Fiberglas units to plaster of

Paris blocks because such units are more sensitive

and accurate when the soils are quite moist.

Light, highly portable models of electrical

moisture meters are now on the market, costing

slightly over $200. This includes the tapered

gage stakes and tapered auger necessary for setting

the gage stakes in selected crop areas. Gage

plugs with 48-inch leads can be used instead of

gage stakes and are somewhat cheaper. If gage

plugs are used, the average nursery will probably

need from 6 to 10 sampling areas involving

different classes of stock and variable soil types.

One gage plug should be buried at appropriate

depth—probably at 2 inches in newly germinating

beds and 6 inches in other beds. The manufacturers' directions should be followed in placing

the gage stakes or plugs, and also in interpreting

electrical resistance readings.

IMPROVING DROUGHT RESISTANCE BY REGULATED WATERING

Jack, red, and Scotch pine, and eastern redcedar often are planted on sandy or shallow soils

or exposed sites, such as south or southwest

slopes. ^ On these droughty sites, mortahty can

be minimized by planting well-rooted, moderately

thick-stemmed, well-balanced stock with rather

small tops to cut down transpiration as much as

possible. One way of obtaining drought-hardy

plants, besides selection of the proper class of

stock, is to apply water rather sparingly during

the year before field planting so that they become

hardened (fig. 39).

In a test of ''drought hardening,'' 2-year-old

jack pine seedlings given only 2.25 inches of water

in 3 waterings were more drought resistant than

seedlings receiving no supplemental irrigation

and those receiving 4.75 and 7.00 inches. Excessive irrigation tends to reduce drought resistance, but too little watering actually weakens

the plants.

The total percent of moisture in the surface 4

mches of typical loamy sand nursery soils at the

start of irrigation in first-year seedbeds commonly

IS at least 8 percent. Therefore, 1 or 2 hours of

watering are sufficient. Second-year seedbeds or

transplant beds usually are allowed to dry down
F-3752S7

FIGURE 39.—2-0 jack pine. Two plants on left are from

plot subjected to normal watering conditions. Two

plants on right are from plot receiving excessive water

throughout the growing season. (Chittenden Nursery,

Wellston, Mich.)

to about 7 percent total moisture (or 3 percent

available moisture) before water is applied. To

soak up the top 8 inches of soil adequately will

require 4 to 6 hours of irrigation with a sprinkler

system that applies 0.125 inch of water per hour

(fig. 40).

/ /

/

// y é>^

M ,/Ar

ÏÏ .#áy

OX

0/

/

i ^

/ /

y/i

/

^y

Ü

^

0.2 0.4 0.6 O.r 1.0 1.2 1.4 1.6 1.8

WATER APPLIED (INCHES)

1 1 1 1 1 1 1

2 4 6 B 10 12 14

OVERHEAD IRRIGATION (HOURS)

FIGURE 40.—Computed and actual rise in soil moisture

content of a loamy sand n\irsery soil after various intensities of irrigation. The difference between computed and actual soil moisture content is due to losses

by evaporation, transpiration, and underdrainage.

70 Agriculture Handlooh Í10, V. S. Department of Agriculture
SEEDBED CARE DURING GERMINATION AND THE

SEEDLING STAGE

The germination stage of 10 to 30 days or more

is most critical because the tender seedlings are

easily injured. Mulches should be removed in

the spring when conditions are favorable and

the danger from killing frosts has passed. Although they can be left on the beds until after

the seeds have germinated, they should be removed before the seedcoats appear above the

ground; otherwise, the seedlings may be seriously

injured at the time the mulch is removed.

To prevent undue injury to the seedlings, great

care should be used in taking up burlap or in raking

straw mulches from the seedbed. Fiber or wiretine rakes are better than ordinary garden rakes for

removing straw mulches. Itis also important that

all of the mulch be removed. If it is not removed

completely, losses are apt to occur as a result of

excessive moisture and of root rot disease that was

stimulated by decomposition of the mulch.

Hardware cloth screens (p. 40) should be kept in

good condition by careful handling and replacement of broken cross slats. This will prevent

openings through which rodents and birds can

gain access to the seedbed; it will also prevent

damage to the seedlings from sagging screens.

The screens should be left on the seedbeds until

germination is complete and nearly all of the

seedlings have shed their seedcoats.

HALF-SHADE

In Lake States nurseries such species as the

spruces, balsam fir, Douglas-fir, hemlock, northern

white-cedar, and sugar maple develop better

seedling stands if they are grown under half-shade

the first season. Other species may require shade

if grown south of the 70° F. average July temperature isotherm, which includes, roughly, the southern halves of Minnesota, Wisconsin, and the Lower

Peninsula of Michigan. Here even white pine

may require shade in the first season. Half-shade

is usually put on in late spring and left until late

August or early September.

Half-shade from the right height may increase

the stand of white spruce seedlings by 20 to 50

percent. Trials at the Hugo Sauer Nursery in

Wisconsin indicated that the shade fence should

be placed 8 to 12 inches above the seedbed surface

for this species (table 28). Where the half-shade

was only 4 inches high, the stand was actually

poorer than without shade because of stagnation

and heating of the air. When the shade slats ran

north and south, results were slightly better than

when they ran east and west.

Forest Nursery Practice in the Lake States

The most efficient method of providing halfshade is to use 48-inch-wide slat-wire snow fence

supported on 2 strands of No. 9 wire placed about

40 inches apart. The wires in turn are supported

on 13- to 14-inch-high wooden horses placed across

the beds at intervals of 12 feet. These horses,

made entirely of 1- by 2-inch creosote-treated

stock, have an overall width of 48 inches, and their

legs are 15 inches long with a base spread of 17

inches. Because they are made without cleats for

bracing, they can be stored compactly by nesting

one on top of the other.

The wire rests on top of the horse in a small notch

cut 4 inches from each end in the cross member.

Each pair of wires runs the full length of the seedbed unit, usually 200 to 500 feet. They are

drawn taut by a block and tackle and fastened to

3-inch-diameter stakes driven in at an angle at

each end of the bed. A modification of this

method is to support the wire on 1- by 2- by 48-

inch crossbars tacked to posts or stakes placed at

12.5-foot intervals on each side of the beds (fig.

A second method involves supporting the rolls

of snow fence on horizontal wooden stringers of

1- by 2-inch or 1- by 4-inch material nailed to

stakes driven at 4- to 6-foot intervals on each

side of the bed. One method at the Chittenden

Nursery in Michigan utilizes a 15-inch-long iron

bedboard stake placed upside down and hooked

underneath the 1- by 4-inch bedboard. The

shades used are handmade in sections 4K by 12

TABLE 28.—Efect oj height oj halj-shade and orientation of the beds and drills on a stand of white

spruce, Hugo Sauer Nursery, Wis.

Trees per square

Direction of Direction of Height foot

seedling slats in

shade

of slats

drills 1 above

frames i ground As 2-0

stock

As 3-0

stock

Inches Number Number

NtoS E to W 4 35. 1 31. 1

N to S E to W 8 48.9 43. 6

NtoS Eto W 12 48. 1 44. 8

E to W N to S 4 33. 8 32.8

E to W Nto S 8 60.6 54. 4

Eto W Nto S 12 53.9 48. 1

Eto W Nto S 16 42. 3 39. 4

Nto S No shade {') 41. 6 39. 4

1 N, S, E, and W refer to North, South, East, and West

respectively.

2 No shade.

71
'ii^trè* ¥

t* 9 gage galvanized

iron wire

•12-6"

V

f

A dE inniniiniPiini'Fijii""'-^

Rolled lath shade FiGUEE 41.—Method of

supporting slat-wire snow

fence used as half-shade.

•lOO'-O"-

-12-6"-

Crossbars

12-6"

^I"x2"x30"

S Stakes

-^^ 1/

feet. Lath racks are used by some nurseries as

a support for half-shade. When not in use, the

slat-wire snow-fence shade should be stored in

rolls outdoors, with the bottom layer of rolls

resting on poles to minimize rotting of the lath.

THINNING

Occasionally, a seedling stand may be overdense.

This is more likely to occur in small-seeded broadleaf species such as paper birch or elm than in

conifers. The surplus seedlings may be pulled

out or, in the case of conifers, cut off with shears

when their roots are not more than 3 inches long.

The beds should be well moistened before thinning

and again afterwards. Studies on thinning 2-0

white pine stock in the spring of the third growing

season indicated that relatively early thinning,

preferably in midsummer or late summer of the

first year, is required to produce the maximum

benefit.

WATERING

After seeding and during the germination period,

nursery beds require frequent, often daily, light

watering except when there is enough rain to keep

them moist at all times. Usually, from 0.10 to

0.25 inch of water, or about 1 to 2 hours' application from an overhead system, is sufficient. In

periods of extreme heat or strong, drying winds,

two waterings daily may be necessary. When the

seedlings are 6 weeks old, watering need be done

only twice a week, applying 0.25 to 0.50 inch of

water in 2 to 4 hours of overhead irrigation.

Details on regulation of watering, and instruments

and methods of measuring moisture, are given in

another section (p. 67).

72

Watering also is a defense against late spring

frosts which may damage newly germinating trees

or succulent growth on such stock as first-year

spruce. Water systems usually are turned on in

the late evening or during the night as soon as

temperatures drop to 30° F. The watering prevents freezing of the plant tissue because the

water temperature is higher than that of the air.

When temperatures have dropped as low as 20°

to 22° during watering, a thin sheet of ice forms

but this promptly melts the following morning

and the tender spruce seedlings generally are

undamaged except for occasional breakage.

CULTIVATION AND WEED

CONTROL

To remove weeds and to prevent compaction of

the surface soil, it is necessary to cultivate, especially in second-year seedbeds or transplant beds.

First-year seedbeds of conifers generally are handweeded or treated with mineral spirits to control

weeds. However, some nurserymen use bedstraddling, tractor-drawn machines, beginning

about midsummer, to cultivate the soil between

rows of first-year pines. This practice reduces

the cost of hand weeding. Usually, a few cultivations a year suffice unless weeds are especially bad.

Broadleaves, handled in more widely spaced drills,

can be cultivated readily with a two-wheeled

garden tractor or larger rubber-tired tractors

equipped with cultivating tools.

Probably no phase of nursery work has changed

as rapidly in the past decade as has chemical weed

control. Before 1940, sulfuric acid and zinc sulfate were used (182), but since that time several

newer chemicals have been employed. There are

Agriculture Handbook 110^ Ü. S. Department of Agriculture
two general classes of chemicals: (1) those to be

applied before or immediately after seeding as a

pre-emergent control; and (2) those to be sprayed

on the tree crop after it has emerged; they kill

the weeds but do not injure the trees.

Among the chemicals used for pre-emergent

treatment are methyl bromide, sulfuric acid, zinc

sulfate, allyl alcohol, chlorobromopropene, parachlorophenyl dimethylurea, sodium chlorate, carbon disulfide, and chloropicrin. The chief postemergent sprays used are mineral spirits (known as

white spirits of petroleum in some European

countries) that can be purchased from leading oil

companies under a variety of trade names. See

p. 118, Safety Rules and Precautions in Handling,

Mixing, and Applying Chemicals.

Sulfuric aci(i.—Sulfuric acid, usually applied as

a control for damping-off immediately after seeding, has a supplemental value in reducing the

number of weeds that appear in seedbeds in the

2- to 4-week period after treatment. The reduction in number of weeds may be as much as 50 to

80 percent in this period. Usually, concentrated

commercial sulfuric acid is applied in about a

2-percent solution with water, using from Ke to )i

fluid ounce of the concentrated acid (before dilution) per square foot of seedbed.

Zinc sulfate.—When applied at the rate of 8

grams (ZnS04-7H20) in 250 cubic centimeters of

water per square foot immediately after seeding

the beds, zinc sulfate has reduced the weed stand

some 80 percent {182). A new application must

be made with every new crop; on the second tree

crop, the amount of chemical can be cut in half.

Because there is some danger of creating a toxic

condition for trees with zinc sulfate, other herbicides are favored in Lake States nurseries.

Methyl bromide.—Methyl bromide is a gas toxic

to weed seed, and its use is especially adaptable to

small nurseries having no more than a few acres

in seedbeds. It is applied to prepared seedbeds

at the rate of 1 pound per 100 square feet a few

days before seeding. By means of a special

injector, the gas is forced under waterproof paper

or plastic material that is rolled out on the beds

and the edges held down with soil. The covers

are removed after they have been in place for

about 24 hours. Seeding can take place 2 to 3

days later.

In tests made in 1950 at the Hugo Sauer

Nursery, there was complete lack of weeds for at

least 22 days after treatment {165). At the end

of 36 days there was only 0.5 weed per square foot

in treated beds compared with 7.7 weeds per

square foot in check beds. The average weight

of 2-0 seedlings was nearly identical in both

treated and untreated beds (0.075 and 0.073

ounce, respectively). However, the foliage of

trees in treated beds was slightly off-color. The

cost of treatment on a larger scale in a Missouri

nursery was $335 per acre in 1951, including

amortization of vinyl plastic covers {76). Hand

weeding in this nursery, where weeds were an

Forest Nursery Practice in the Lake States

especially serious problem, would have cost $550

per acre.

Methyl bromide functions best if applied when

soil temperatures are 50° F. or higher. Besides

its weed-control value, it may also have some

value as a damping-off and insect control. Clifford

{31) noted a complete kill of white grubs in beds

after application of this chemical. Two pounds

per 100 square feet are generally recommended

for damping-off control.

Allyl alcohol (CH2-CH-CH2OH).—This weedseed killer has shown excellent results in trials at

the Hugo Sauer, Wis., and Eveleth, Minn.,

Nurseries {161). Application of a 0.2-percent

solution at the rate of 5,000 to 10,000 gallons per

acre in trial beds reduced the weed stand 81 to 89

percent of that in check beds at the end of 2

months. The trial beds were thoroughly prepared

for seeding and treated a week to 10 days prior to

sowing when the soil temperatures were at least

60° F. The soil was disturbed as little as possible

in the seeding operation.

Allyl alcohol is used as a standard weed control

at Mt. Shasta Nursery in California {81). There,

4.5 gallons of this product are mixed with 45.5

gallons of water in a tank and this solution is

forced under high pressure into the overhead

sprinkling system while it is in operation. With

a 400-foot pipeline unit, about one-haK acre can

be treated in 15 to 20 minutes. Costs per acre

are approximately $27 for chemicals and $3 for

labor.

The toxic nature of this chemical and precautions needed in its handling {144) have acted

somewhat as a deterrent to its wide-scale use. It

has the further disadvantage that when applied

through the overhead system, drift of spray may

injure adjoining beds of seedlings or transplants.

Chlorobromopropene.—This chemical destroys

weed seeds in about the same manner as allyl

alcohol. However, results obtained with it were

not as good as those obtained with allyl alcohol

in tests run in 1951 at the Hugo Sauer Nursery,

Wis. Its toxicity to humans and precautions

required in handling have, as with allyl alcohol,

been a deterrent to its wide-scale use.

Other chemical controls for weeds.—Another preemergent, pre-seeding treatment employs carbon

disulfide in 2-ounce doses placed in holes 6 to 8

inches deep and spaced 18 inches apart {59).

Each hole must be sealed with soil. As little as

1,600 pounds of carbon disulfide per acre may be

satisfactory on a sandy soil, but heavy soils require 2.5 to 3.0 times that much. Summer treatment has been found best. Carbon disulfide is

used chiefly to kill deep-rooted, perennial weeds.

When applied as a weed killer, it has other values,

such as control of white grubs and nematodes.

This chemical is explosive in the presence of flames

and should be handled with care.

Sodium chlorate has been applied in spray form

for deep penetration, using 3 pounds in 3 gallons

of water.

73
Chloropicrin has been used experimentally at

the rate of 7 cubic centimeters of chemical per

cubic foot of soil, covered with light paper, and

left for 3 days r¿^e).

Hydrin, a hydrocarbon obtained from coal, is

a good weed-seed killer when appled at 10 gallons

per acre, along with ample water, immediately

after seeding. It was used successfully in tests

at Hugo Sauer Nursery, Wis., in 1953 on jack and

red pines and black locust but larger scale trials

are needed.

Mineral spirits or white spirits.—Mineral spirits

are the most widely and successfully used herbicides in conifer nurseries in the Lake States as

well as elsewhere in the United States (fig. 42).

They are not used to any extent in broadleaf

nurseries because hardwoods, with some exceptions, are generally injured or killed by the spray.

Made from petroleum, mineral spirits have an

initial boiling point of 300° to 320° F., API gravity

of 48 to 50, and an aromatic hydrocarbon content

of 10 to 20 percent.

Mineral spirits are especially effective on small

weeds K to 2 inches in height or spread. Within

3 to 12 hours after being sprayed, many turn light

gray or brown and die within a few days. However, some weeds, notably purslane, Canada

thistle, quackgrass, and larger clover plants, resist treatment. Mineral spirits used in the Lake

States generally contain 10 to 12 percent of

aromatic hydrocarbons and are usually applied

fuU strength at the rate of 25 to 75 gallons per

acre, at pressures ranging from 50 to 100 pounds

per square inch (table 29). Three or four applications per season are generally made. Some

nurserymen use as many as 6 to 8 per season.

Weed kill appears to be approximately proportional to the content of aromatic hydrocarbons in

the mineral spirits used. For instance, in 1950

it was observed that a treatment of 80 gallons per

acre with mineral spirits that had a 12 percent

aromatic content gave approximately the same

kUl as 45 gallons per acre of spirits with 22 percent

of aromatics {156).

Pre-emergent spraying of 50 gallons per acre on

jack pine beds immediately after seeding in late

June gave 86 percent weed reduction; spraying

100 gallons gave 92 percent weed reduction.

According to observations by A. L. Nelson, preemergent sprays at the GrifRth State Nursery in

Wisconsin were effective in May but were ineffective in April, probably because weed seeds in

April were somewhat dormant and more resistant

to the sprays.

Although pines, spruces, firs, and junipers

tolerate mineral spirits and a few closely allied

petroleum products {35, 44, 125, 153, 154) other

conifers, notably the larches, do not tolerate

mineral spirits. Some tree species are moderately

sensitive and may show injury if more than about

40 gallons per acre are applied in any one treatment. Still other species, such as red pine and

jack pine, appear to tolerate as much as 80 to 100

or more gallons per acre of spray with little or no

harmful effect.

Young seedlings are somewhat susceptible to

injury during the first 3 or 4 weeks after germination. Consequently, spraying during this period

should be avoided except for such resistant species

as red and jack pines which may be given very

light dosages of 20 to 30 gallons per acre. Mineral

spirits are not likely to damage older conifer

seedlings when sprayed at air temperatures under

80° F. Likewise, they show less damage in beds

of spruce, balsam fir, and white pine, where the

half-shade is replaced shortly after spraying, than

in beds open to full sunlight.

74

FIGURE 42.—Spray rig for applying mineral spirits.

Agriculture Handhooh 110, Ü. 8. Department of Agriculture
TABLE 29.—Saje dosages of mineral spirits jor

conifers in Lake States nurseries y using material

containing 10 to 12 percent of aromatic hydrocarbons

Species

Douglas-fir

Fir, balsam

Juniper, Rocky Mountain

Pine:

Austrian

Eastern white

Jack

Mugho

Ponderosa

Red (Norway)

Scotch

Western white

Bedcedar, eastern

Spruce:

Black

Blue

Norway

White

White-cedar, northern

Safe dosage per acre ^ for

trees that are—

4 to 6

weeks

old

6 weeks

to 1 year

old

Gallons

0

30

30

40

40

50

40

40

50

40

35

30

30

25

25

30

0

Gallons

40

40

40

50

60

60

50

60

60

50

40

40

50

30

40

50

30

1 +year

old

Gallons

50

50

60

60

75

75

60

75

75

60

60

60

60

40

60

60

40

1 First spraying of first-year beds should be done after a

few of the trees have emerged, or before emergence if weeds

have germinated. Thereafter, no spraying should be

done until the seedlings are about 4 weeks old.

The usual cost for labor and chemicals (with

labor at about $0.80 per hour and mineral spirits

at $0.25 per gallon) is $18 to $20 per acre for 1

application. Hand weeding in the Lake States

costs 3 to 4 times this amount. Considering all

spraying costs and hand mopup of weeds escaping

kill, spraying with mineral spirits reduces overall

weeding costs by 50 to 60 percent compared with

hand weeding. In the South, Cossitt (35) reports

savings up to 90 percent. The superintendent

of the Wisconsin Conservation Department nurseries, W. H. Breuer, reported an annual saving

of about $18,500 after mineral spirits were adopted

as a standard weed control method in 1949.

Some nurserymen have used gasoline weed

burners to destroy weeds about 10 days after

seeding and just before tree emergence! Wells

(186) reports cutting weeding costs in half by this

procedure.

TOP AND ROOT PRUNING AS A SUBSTITUTE FOR TRANSPLANTING

Top and root pruning of seedling conifers has

been used to some extent in the Northeast (SO)

and in the Lake States as a substitute for transplanting. Top pruning has been practiced largely

on second-year jack pine that often becomes 8

Forest Nursery Practice in the Lake States

to 14 inches high in nurseries of good fertility. On

droughty sites where this species commonly is

plaated, these topheavy seedlings survive poorly—

especially if fall-planted. Although top pruning

is viewed to some extent as an emergency measure,

it may improve field survivrai of topheavy, fallplanted jack pine as much as 15 percent. It is

of less advantage in spring plantings.

Normally, the tops of 2-0 jack pine are pruned

in May or early June of the second year while

the new growth is expanding rapidly. The tops

are cut 1 to 2 inches above the end of the previous

season's wood, usually removing 1 to 3 inches

of new growth. The treatment does not adversely

affect subsequent bud formation or the normal

development and form of the tree. By the end

of the second year the tree is shorter, has better

balance (a more favorable top-root ratio), is less

spindly, has less transpiration surface, and generally is a sturdier, more drought-hardy plant.

Moreover, under field planting conditions the

plants are less likely to be flattened down by snow,

wind, or heavy, beating rains, or to be frostheaved.

A pair of hedge shears with blades 10 to 12

inches long or a sharp, thin-bladed scythe in the

hands of a skilled workman is satisfactory for

top pruning on a small scale. The preferred

method for large-scale operations is a power

mower of the type normally used in cutting hay.

It is pulled by a rubber-tired tractor that straddles

the bed, and an entire 4-foot-wide bed is pruned

at once. The end of the bar is usually supported

on a shoe or small ''sled'' to hold it at the desired

height above the beds. Some nurserymen use a

small, one-wheel, power mower with a bar 2)^

feet long. With this device, 2 trips are made for

each 4-foot-wide bed, taking about half the width

of the bed at one time.

Top pruning of 2-0 jack pines when they are

dormant or when the stems are woody has proved

harmful. For example, in 1937 a lot of 2-0 jack

pine was pruned while dormant. On some of the

trees, the tops were severed one-half inch below

the terminal bud; others were pruned to a 3-inch

length, removing perhaps 1 inch or more of the

top; the remainder was not pruned. Shortly

thereafter the trees were field-planted in replicated plots. Field survivals at the end of the

first year were reduced 15.4 to 21.1 percent by

top pruning (table 30).

Eoot pruning in place in the spring has also been

used to some extent on 2-0 jack pine in an attempt

to develop a more fibrous, compact root system

and to reduce top length (fig. 43). The best results in such cases have come from root pruning

at a depth of 3 to 5 inches in the spring of the

second year. Sometimes root pruning combined

with top pruning fosters good field survival, especially in very top-heavy stock scheduled for fall

planting.

The effects of root and top pruning, and of coating the needles with a wax substance just before

75
TABLE 30.—Effect on field survival of top pruning

dormant 2-0 jack pine just before planting

c3 >

Causes of mortality

Treatment in o u CO

nursery

+3

^ m Ï

bC ÄT3 »,

X5 ;3

O Ö§ m

;H U O ^ 03

P^ O P O m

Per- Per- Per- Per- Numcent cent cent cent ber

Not pruned 73. 0 1. 5 22.2 3. 3 1, 000

Pruned to point %

inch below terminal bud 57.6 1.0 25.0 16. 4 978

Pruned to a 3-inch

top 51. 9 1. 4 28. 9 17.8 1,000

1 Least significant mean difference at 1-percent level is

9.85. Both pruning methods proved harmful at odds of

99 out of 100.

shipment to the field planting site, were tested on

the Nicolet National Forest in northeastern Wisconsin and on the Upper Michigan National Forest

in the fall of 1940 and spring of 1941 (table 31).

This study brought out the following results: (1)

Spring-planted trees of several species survived

better than those planted in the fall, especially if

the stock was unpruned; (2) root pruning, particularly when done both horizontally and vertically, markedly improved survival of fall-planted

stock; (3) top pruning alone appeared to reduce

survival, even when done in late spring when the

new growth was still succulent; and (4) wax dips

to cut down transpiration were of no benefit.

Fall-planted 3-0 white and red pine stock, root

pruned both horizontally and vertically, survived

23 and 16 percent better, respectively, than

untreated stock (table 31). This result would

seem to warrant pruning trials on a larger scale

because of the relative cheapness of 3-0 stock and

its adaptability to machine planting. Such root

pruning can be done mechanically for as little as

TABLE 31.—First-year field survival in eight separate trials oj root or top pruning in conifers {all stock

planted by hand)

First-year field survival of—

Overall evaluation

Treatment in nursery 3-0 white pine 3-0 red pine 2-0 jack pine

of treatments,

based on statistically valid increase

Fallplanted

Fallplanted

SpringplantedFallplanted

Fallplanted

Springplanted

FallplantedSpringplanted

in survival

None _ __

Percent

65.0

73.8

*78. 3

62.8

t87. 0

66. 7

73.8

*76. 2

Percent

65. 7

t79. 8

74.7

66.7

t90. 2

t83. 2

68.0

t81. 8

Percent

89.0

88.2

89. 3

§75.5

94.8

89.7

87.8

94. 2

Percent

62.6

*80. 6

72.0

§41.6

75.4

t87. 0

62.0

63.4

Percent

51. 0

56.6

48. 0

42.0

t70. 8

57.2

54.4

t70. 4

Percent

94. 0

93.2

92.2

90.0

97.2

94.8

89. 8

96.0

Percent

55. 8

70.8

61. 0

61. 4

62.8

73. 6

58.2

64. 2

Percent

83. 6

83.2

75. 8

Í74. 0

86.6

82.8

85.2

76. 2

Root pruned horizontally______

Root and top pruned

Beneficial in 2 of 8

trials.

Beneficial in 1 of 8

Top pruned

trials.

Harmful in 3 of 8

Root pruned horizontally and

vertically.

Root and top pruned, and

liquid fertilizer.

Tops dipped in wax

Root pruned, tops dipped in

wax.

trials.

Beneficial in 3 of 8

trials.

Beneficial in 2 of 8

trials.

No effect.

Beneficial in 3 of 8

trials.

Average 72.9 76. 3 88.6 68. 1 56. 3 93.4 63.5 80.9

Least significant mean difference in column at 5-percent

level.

10. 8 9.28 8.3 15.4 12. 46 4.6 8. 36

Least significant mean difference in column at 1-percent

level.

14. 47 12.43 11. 1 20.8 16. 78 11.28

* = Significantly better than untreated check plot at 5-percent level.

t= Significantly better than untreated check pilot at 1-percent level.

t= Significantly poorer than untreated check plot at 5-percent level.

§ = Significantly poorer than untreated check plot at 1-percent level.

Y6 Agriculture Handbook 110, Ü. S. Department of Agriculture
FIGURE 43.—Root pruning of 2-0 jack pine in the spring

of the second growing season improves balance, reduces

spindliness, and produces a more fibrous root system.

Left, 2 unpruned trees; right, 2 trees root pruned at a

depth of about 2.5 inches. (Background is 1-inch

squares.)

F-454518, 454520

FIGURE 44.—Barton root pruner mounted on a Wind

River lifter frame. The cutting element is a thin blade

of bandsaw steel 52.4 inches long, 1.75 inches wide,

and 0.08 inch thick, held under high tension by a turnbuckle. It has a depth adjustment and a steering

handle. A, Side view; B, rear view.

10 cents per 1,000 trees compared with a transplanting cost of $1 or $2.

The denser, more fibrous root system caused

by root pruning results in a better balanced tree

at the time of digging. Such trees, because of

greater compactness of the root system, are

easier to field plant. Vertical pruning should,

by all means, be done on the path side of each

outer row of a bed because these two rows particularly tend to develop rather widespreading,

lateral roots running into the paths. Many of

these roots are lost in 3-0 stock of red and white

pines unless root pruning in place is used to create

a more compact root system.

The Barton root pruner does excellent work

in light, sandy, nursery soils that are quite free

of old tree roots left from land clearing, and that

have little or no stone over one-quarter inch in

diameter. This horizontal pruner consists of a

thin blade of bandsaw steel held under tension

with a turnbuckle and mounted on a Wind River

lifter frame (fig. 44). On heavier soils where the

thin blade may tend to buckle, or on newly cleared

sandy soils with considerable stone, sticks, or old

roots, it is advisable to use an ordinary tree lifter

with the lifter shoes removed and the blade set at

Forest Nursery Practice in the Lake States

408189°—57 6

a horizontal or slight forward inclination. The

blade should be hollow ground and kept sharp.

One horizontal root pruner that is suitable for

small-scale experimental trials consists of a thin,

2-inch-wide blade, 52 inches long, bolted horizontally on the bottom of a steel bucksaw-type device.

Lengths of ^^-inch iron pipe are laid in a trench

to act as a rail or depth guide for the pruner. A

small block and tackle is fastened near the ground

line in each path to stakes driven in about 12 feet

ahead of the pruner. The pruner is then drawn

along by two men pulling on the rope, while a

third man holds it in an upright position. Vertical

pruning can be done with a sharp spade or a

small, sharpened, rolling coulter. The job accomplished is similar to that performed by the Barton

root pruner.

For stock grown in drills, vertical pruning can

best be done with sharp, rolling coulters mounted

on an axle and located at the midpoint between

rows. The rolling coulter has an advantage—in

keeping free of refuse and tree roots—^over vertical

individual knives even when these were slanted

downward and backward. Beds containing only

5 to 7 drills and having a space between drills of

6 to 10 inches can be pruned vertically witii less
damage than the 10-row beds with only 4.5 inches,

center to center, between drills.

Vertical pruning with vertically placed knives

has been done simultaneously with horizontal

pruning. However, there was a distinct tendency for tree roots and other refuse to collect at

the slotted junction of the horizontal and vertical

blades. This choke-up resulted in lost time

while the bed was dug up at that point and the

refuse removed.

The beds should be watered thoroughly shortly

after root pruning to prevent temporary wilting

of the trees. Based on extensive observations

of a number of nursery experiments, root-pruned

stock may tend to show a slight nutritional

deficiency. Application of a complete liquid

fertilizer, totaling about 300 pounds per acre of

15-30-15 fertilizer or its approximate equivalent,

within a week or two of root pruning will aid in

maintaining normal, healthy foliage color and

obtaining somewhat higher field survival. The

symptoms of malnutrition are no doubt due to

the severance of about half of the root system.

78 Agriculture Handbook 110^ TJ. S, Department of Agriculture
TRANSPLANTING OPERATIONS

Transplanting, as the term is applied to nursery management, means to remove small seedlings from a crowded seedbed and line them out

where they will have more room to develop.

Seedlings held in transplant beds for 1 to 2 years

are better balanced plants than those produced by

root pruning in place. Because of the added

expenditures involved in transplanting and subsequent care, the cost of transplant stock generally

is much higher than for stock that has not been

transplanted.

Conifers ordinarily are transplanted in the

early spring while they are still dormant. The

work should be started as early as conditions permit. Normal losses are 1 to 3 percent.

A relatively high mortality can be expected

when seedlings are transplanted between June 1

and August 15. Digging the seedlings before

active growth starts in the spring and holding them

in cold storage until transplanted will prevent

some mortality. Even with cold storage, however,

the warm temperatures and dry winds that

commonly occur during June and July may injure

or kill the plants before they become established.

Transplanting has been done successfully from

mid-August to fall in U. S. Forest Service nurseries in the Lake States when ground moisture

conditions were satisfactory. The former Soil

Conservation Service nursery at Winona, Minn.,

had good success in transplanting from August 1

to September 6. Ordinarily, late season transplanting should not be started until about the

middle of August after the stock lias nearly completed its summer's growth. Normal losses from

late summer and fall transplanting are 5 to 10

percent of the trees.

Fall transplants usually require more attention

than early spring transplants because of the less

favorable soil moisture and air temperatures that

normally occur in the fall. If the soil is at all

dry, it should be irrigated before transplanting to

create optimum soil conditions for operating

mechanical trenchers, and to avoid the heavy

losses from planting the trees in dry soil. The

nurseryman will also need to provide adequate

moisture by sprinkling or furrow irrigation immediately after transplanting.

Ordinarily, transplanting should be terminated

by September 20 in order to allow sufficient time

for the soil to settle and the trees to become partially established before severe winter weather.

If the trees are transplanted in the late fall, or a

blanket of snow cannot be expected to protect

them, the beds should be mulched. (See Seedbed

Mulches, p. 65.)

Where trees are to be distributed after only 1

year in the .transplant beds, it is essential that the

transplanting be done in the fall or early spring so

that the trees will have the benefit of a long growing season. This is not so important if the stock

is to remain in the transplant beds for two seasons.

Forest Nursery Practice in the Lake States

LIFTING STOCK FOR

TRANSPLANTING

To insure a minimum of injury in digging tlie

stock, ground moisture conditions should be

favorable, and men assigned to the work should

be experienced and dependable. The practice of

digging the trees with a spade or fork has been

replaced by more modern and efficient methods

in practically all Lake States nurseries. (See p.

37 for a description of mechanical lifters.) However, where only small numbers of trees are involved and the investment in heavy eqidpmeat

cannot be justified, lifting can be accomplished

with handtools. A spading fork is preferred to

the ordinary spade for this work since it is lighter

in weight, can be forced into the grotmd with less

effort, and does less severing of lateral roots.

When a mechanical lifter is used to dig stock

for transplant purposes, the lifter blade usually is

set for a depth of about 7 inches and "dug in" at

the end of the bed to insure proper and uniform

depth of cutting. The lifter should be drawn

slowly through the bed so that it can be controlled

adequately and do a better job of breaking and

crumbling the soil (fig. 45). The lifting of stock

FIGURE 45.—Tree lifter loosening roots of nursery stock.

This particular lifter is operating on a cable and winch

system. (Chittenden Nursery, Wellston, Mich.)

should be correlated with the pulling operation,

and only sufficient beds lifted ahead of the pulling

crew to keep it busy. If too much time elapses

between the two operations, the soil tends to

settle and become compact. This makes the job

of removing the trees more difficult and increases

the amount of mechanical injury to their roots.

To provide good quality stock, it is important

that the pulling crew be thoroughly trained in

the method of pulling trees. Ordinarily, additional spading to loosen the trees is unnecessary

79
if the tree lifter is properly adjusted to soil conditions. However, if the trees cannot be removed

easily, it is good practice to loosen them with a

spade or fork. The crew can work most effectively if it starts on the outside of the bed and

proceeds toward the center. Individual pullers

should be so spaced that they are not working in

close quarters. This will minimize the danger of

flying dirt particles striking neighboring workers

in the eye, and it will also make it easier for the

crew foreman to check the work of each individual.

The plants are less subject to injury if a small

bunch at a time is firmly grasped and removed

from the soil with a steady pull. A light shake

ordinarily dislodges any dirt that clings to the

roots. Undersized or mechanically injured plants

are then discarded, and when a bunch of the

proper size has been obtained, it is heeled in behind the worker with a handful of moist soil over

the roots. This protects the trees from drying

out before they can be pruned and packed.

The pruning and packing will be more uniform

if the work is done by one man rather than by the

individual pullers. A light cleaver is an efficient

root pruning tool. Roots of 1-year-old seedlings

can be shortened to 4 inches without ill effects.

Red pine and white pine 1-0 trees pruned to this

length produce well-balanced 1-2 stock. Twoyear-old seedlings ordinarily are not pruned so

severely for transplanting; the roots of 2-0 red

and white pines and 2-0 black and white spruces

ordinarily are shortened to 4^ or 5 inches.

PREPARATION OF THE

TRANSPLANT BED

Soil for transplanting is prepared in the same

general manner as that prescribed for seedbeds^

(p. 59). The work of tilling and leveling should

be completed far enough in advance of transplanting to permit the soil to settle. Moderately compact soil is particularly important where mechanical equipment is used for opening the trench or

the transplanting is done by machine, because

there will be less sloughing of the walls of the

trench. The amount and type of ground preparation for spring transplanting will vary from

season to season, depending upon overwinter

conditions. However, if the soil is placed in good

tilth just before winter, little additional work will

be required in the spring.

In laying * out transplant beds, consideration

should be given to the method of transplanting

and the type of machinery to be used in the subsequent operations, particularly where overhead

irrigation has been installed. Usually, a slightly

wider path is required between outside beds and

irrigation lines than is required between beds.

Since the pattern of the beds will be governed

by the initial bed, it is important that special care

be used in laying out that bed. A string should

be stretched full length of the field, parallel to

the overhead lines, to serve as a guide for the

tractor operator. After the first trip has been

made, the wheel marks will serve as a guide for

adjacent beds.

TOP VIEW OF HITCH

END VIEW

SIDE VIEW

j steel plate

80

FORD TRACTOR HITCH

ATTACHMENT

FIGURE 46.—Details of a specially designed transplant trencher.

Agriculture Handbook 110^ Ü. S. Department of Agriculture
Ordinarily, tiie small tronchos in wliich the

troos arc set are made with some type of powerdriven equipment. Trenching with a spade or

hand trencher of special design is expensive and

can be justified only where the transplanting

operation involves very small amounts of stock.

The type of hand-trenching device commonly used

is made of 2 plates of steel 8 to 10 inches wide and

18 to 24 inches long, welded together to form a

wedge-shaped tool. A T-handle 20 to 24 inches

long is attached. The operator steps on the tool to

force it into the ground, and moves the handle

back and forth to produce a V-shaped trench 6 to 8

inches deep and 2 to 3 inches wide at the top.

Trenchers of this type are not favored for heavy

soils but can be used effectively in light sandy

loam.

Mechanical trenching can be accomplished efficiently and economically with a small plow or a

specially designed trenching tool (fig. 46). The

trenching tool makes a V-shaped trench by compressing the soil as it is drawn through the bed.

Since it makes a cleaner and more uniform trench

in light sandy soils than can be obtained with a

plow, it is favored by nurserymen in the Lake

States.

Although a steady horse may be used to draw

the trenching equipment, a tractor wide enough

to straddle the bed ordinarily will do a better job.

The tractor should be equipped with a special

drawbar to which the demountable trencher can

be attached and adjusted according to the spacing

desired. In order to plant without interruption^ a

trench is made when the tractor makes one trip up

a bed, and another trench is made in the adjacent

bed on the return trip. The trencher is then moved

to a new position on the drawbar for the next trip

(fig. 47). Seven rows, spaced 7 inches apart, per

bed are standard in U. S. Forest Service nurseries

in the Lake States.

METHODS

The amount of transplanting to be done will

dictate to some extent the method to use. In small

nurseries where only a few hundred thousand trees

are transplanted each season, the work can be done

by hand about as easily and effectively as by machine. However, for large nurseries where several

million trees require transplantmg, some type of

machine generally is used. Machine planting is a

particularly desirable method where there is a

shortage of dependable labor. Both methods

require thorough planning and good organization

to accomplish the job efficiently and economically.

Where the trenching is done by hand, a transplant crew is composed usually of a trencher, a

planter, and a threader. The trencher makes the

trench in which the trees are to be planted, the

threader places the trees in the boards, and the

planter sets the trees in the ground. An efficient

3-man crew will transplant 20 to 25 thousand trees

per 8-hour day.

Forest Nursery Practice in the Lake States

FIGURE 47.—A tractor-drawn trencher in position. Operator rides tiiis trencher to control depth and aid in

steering.

The quantity of work, in terms of number of

trees planted per day, and the quality, measured

in terms of survival, depend to a large extent upon

the proficiency obtained by each member of the

crew in doing his particular job. It is essential

that the various jobs be thoroughly analyzed and

the personnel carefully selected and trained for

the work to be performed. The planters and those

making trenches should have good physiques and

be able to stand the constant walking, bending,

and tamping that the work of hand transplanting

requires.

Spacing

The spacing to use in lining out stock varies

with species, size of stock, and method of transplanting. It is therefore important that spacing

be given full consideration, since the amount of

stock that can be raised per unit of area depends

on it. This is particularly true where the planting

area is limited.

In hand transplanting, the spacing between

seedlings commonly is 1 to 1}^ inches for 1-0

stock, and 1% to 2% inches for 2-0 stock. Where

older stock is transplanted, or where the plants

are to be left for 3 years or more, a spacing wider

than 2% inches should be used.

In a spacing test, 2-0 white spruce transplanted

and left for 2 years showed a 6-gram or 40-percent

increase in average green weight per plant and a

considerable increase in stem diameter when spacing was increased from 1^ to 3 inches. Even

the stock grown at a iK-inch spacing was entirely

adequate in size for good field results. Therefore,

there appears no reason for using spacing greater

than 2 inches for 2-2 spruce. In the 4 spacings

81
tested, all of the trees were of excellent balance,

with top-root ratios of 1.83 to 2.00:1.

Hand methods of transplanting facilitate slightly

closer spacing between the rows than mechanical

trenching or machine transplanting. The spacings that have proved effective in U. S. Forest

Service nurseries in the Lake States are 6 inches

for hand transplanting and 7% inches for machine

transplanting, with plants 2}i inches apart in

the row.

Hardwood species usually are planted with a

9- to 14-inch space between rows or with 4 or 5

rows per 4-foot-wide bed. This spacing is adequate for the use of mechanical equipment for

cultivating and for lifting the trees. Regardless

of the spacing accepted as optimum, it should

be uniform and regular enough to permit the

use of standard methods and equipment for

handling the weeding, cultivating, and digging of

the stock.

Hand Transplanting

Hand transplanting (fig. 48) can be accomplished by setting the plants in the trench by hand

or with a transplant board (fig. 49). The latter

method is most commonly used because it is

faster and more efficient. Various types of transplant boards have been designed by nurserymen

iDased upon local requirement and personal preference {27, 95, 107, UO, 169).

The speed of hand transplanting has been improved gradually and costs of aftercare lowered

by (1) using a longer board, (2) somewhat closer

spacing of notches in the board, and (3) partial

or complete mechanization for making the trench

or furrow in which transplants are placed. A

change in row direction, i. e., from short, crosswise rows to long, continuous rows better adapted

to mechanical cultivation, was also made.

In U. S. Forest Service nurseries, a transplant

board 8K feet long and accommodating 50 to 75

plants has proved very effective. With such a

board, production averages 11 thousand trees

per man-day, using one foreman to five 2-man

crews (1 stringer and 1 transplanter). The foreman opens the furrow with a horse-drawn 7-inch

plow, and the crews set the plants in rows spaced

8 inches or slightly more apart.

Because seedlings must be protected from drying

out, their threading into transplant boards should

be done in a shelter. The shelter commonly

used in Lake States nurseries is a skeleton frame

made of light material and covered with canvas.

Its front is left open or canvas naps hang loosely

to provide easy access for the planter when changing boards.

Two shelves are provided in the shelter, one

for the transplant board that is being filled and

the other for the empty board that is returned

by the planter. These shelves, one about 15

inches above the other, should be placed at a

convenient working height for the threader so

that he can keep the boards filled at a steady pace.

It is important that the shelter be long enough

to accommodate the transplant boards, and that

sufficient space be provided to keep a supply of

seedlings at each end of the shelter.

To save time and walking, the threader starts

at one end of a board, completes it, and closes the

board. He then moves in the opposite direction

as he fills the board that the planter has returned

to him. Because the threader sees each seedling

as he threads it, he should be trained to recognize,

inferior trees and instructed to discard them.

In setting the seedlings, the planter takes a filled

board from the shelter and walks toward the open

trench. As he approaches, he turns the board so

that it can be easily opened after the planting is

completed. He stands far enough back from the

FIGURE 48.—Hand transplanting in nursery on

Chippewa National Forest, Minn. The man at

loft is making a trench,

and the man in center is

tamping a board of 30

trees. The crew consists

of 2 threaders (women)

in transplant shelter in

rear, 2 planters, and 1

trencher.

82 Agriculture Handhooh 110, U. S. Department of Agriculture
ti II II II II II II II II II II II II II II II INI II II il II II II il 11 il

Front

m -li

Metal strip^

Edge detail

FíGUBE 49.—Details of construction of a 5-foot transplant board (49 seedlings per board).

trench to prevent caving in the walls, and with a

slight swinging motion of the board places the

roots of the seedlings in a natural position in the

trench. When he has lowered the board to the

proper point, he tilts it away from him and rests

it on the far side of the trench. He then stands

erect and with one foot firmly tamps the soil about

the roots of the seedlings as he moves from one

end of the board to the other; he opens the board

and returns it to the shelter for refilling.

If soil preparation and setting and tamping the

trees are done properly, very little additional work,

such as removing excess dirt from the crowns of

the plants and filling in low spots, will be required.

To minimize the time a planter spends walking,

transplant shelters should not be more than 100

feet apart.

Fox (51) introduced the novel idea of each

planter threading his own board. This eliminates

any time lost by threaders and planters in the

Forest Nursery Practice in the Lake States

exchange of boards, and it relieves the monotony

for the planter of doing only a single operation.

The system works well if the individuals are skillful both as threaders and planters.

Machine Transplanting

Although hand and machine transplanting differ

in method, the fundamental principles involved

are the same. The soil must be thoroughly tilled

and leveled and the beds laid out carefully for

either method. For machine transplanting, however, it is especially important that the soil be

slightly moist and free of stones, lumps, and debris.

If the soil is not in optimum condition, the machines require additional labor to tend and operate

them.

The machine plants in two beds simultaneously

(fig. 50). To facilitate turning at the ends of the

beds and to increase the efficiency of the operation,

planting is done in 2 beds when going in one direction and in 2 adjacent beds on the return trip.

With the type of machine used in U. S. Forest

Service nurseries in the Lake States (fig. 16, p. 36),

the rear driving wheels travel on the area that

becomes the center of a bed when planting is

completed.

On the first trip, the demountable plant setters

are set side by side and 10 inches from the center

on the drawbar. On the next trip they are each

moved one row away from the center of the drawbar to plant the second row in each bed. When

the third row in each bed has been similarly

planted, the plant setters are moved 2 spaces and

the next 3 rows in each bed are planted in order.

The final rows planted in each bed are the center

rows that fall in the tracks of the driving wheels.

Only 1 furrow to a set of 2 beds is required for the

steering shoe. This method of operation equalizes

the draft on the power unit of the machine, and

the machine operates with a minimum of attention.

In starting, a wire is stretched the full length

of the first bed to mark the location of the guide

furrow. This furrow, made either with a triangular hand hoe or a wheel hoe, should be 2 to 3

FIGURE 50.—Method of obtaining two 7-row beds of

transplants with row spacing of 7 inches and providing

for a 20-inch path between beds. The paired numbers

1-1 to 7-7 represent position of the 2 planting units and

the order of planting of the paired rows. A, Planting

units; B, steering shoe; C, main drive wheels.

83
inches deep and wide enough to accommodate the

shoe of the self-steering device on the machine.

Guide furrows in adjacent beds can be made with

a marker wheel attached to the machine. To

insure straight, evenly spaced rows, the guide

furrows should be kept free of loose soil and in

good alinement. To prevent deviating from the

prescribed course, the machine must be kept balanced, particularly as concerns the draft placed

on the power unit by the two planting units. The

operators selected to thread the seedlings into the

pockets on the revolving disks, therefore, should

be approximately the same weight.

Before starting a trip across the field, the transplanting machine is lined up on the beds with the

center of the tractor in line with the guide furrow,

and the steering shoe is placed in the V-trench.

The unit is then driven into position for planting

to begin. Next, the plant setters are attached to

the drawbar in the proper position and the

operators take their places on the seats. After

each operator has taken a handful of seedlings,

the machine is put into motion. The operator

holds the seedlings in his left hand and with his

right hand places a single seedling in each plant

pocket on the revolving disk as it comes around in

position. When one handful of seedlings has been

planted, another is taken from a box that is

within reach, and the threading of trees continues.

The plant pockets are spaced either 2% or 2K

inches apart on the disk. The speed at which the

disk turns varies with the gear ratio used on the

disk and the packing wheels that furnish the

power for turning the disk. Therefore, the spacing

of plants can be increased or decreased by adjusting the speed at which the disk turns. Standard

spacing in U. S. Forest Service nurseries is 2}í

inches, or approximately 5.4 seedlings per linear

foot.

It is essential that the furrow-opening shoe be

set deep enough to permit the roots of the seedlings to hang straight when they reach an upright

position. If the seedlings are set at an angle, or

the roots are planted in a horizontal position, the

plant develops a crooked stem and is difficult to

handle when field planted.

Where more than one machine is operated in

the same general area, a foreman is usually

assigned to supervise and direct the work. It is

his. duty to assist in turning the machines at the

ends of the beds, to lay out new beds for planting,

and to service the machines with seedlings. To

avoid interruptions in the planting work, a supply

of seedlings is kept at each end of the bed.

The production obtained by machine planting

varies with the size and age class of seedlings

planted, and the amount of ineffective time used

in turning and servicing the machine. At the

U. S. Forest Service nursery in the Lower Peninsula of Michigan, where the length of beds ranged

from 450 to 500 feet, a production of 30 thousand

trees per 8-hour day was obtained with one

machine.

The Soil Conservation Service nursery at

Zanesville, Ohio, has devised a multiple-row

planter that can plant as many as 6 rows simultaneously; 6 individual transplant units are

mounted inside of a shelter on wheels. For

traction power a wide-tread, caterpillar-type

tractor is used. It was geared down to a speed

of Ys to ji mile per hour by adding a light truck

transmission.^^ This machine provides uniform

row spacing, is easy to turn, shelters the trees,

reduces supervision costs, increases production

per man-day, and is easy to maintain.

A very compact 5-row transplanter with a

short turning radius was built in 1953 at the

Nekoosa-Edwards Paper Company industrial forest nursery. Port Edwards, Wis. An ordinary

rubber-tired tractor was geared down to obtain a

speed of about 10 feet per minute, and standard

Holland transplant units were so mounted on it

that 2 of them were between the forward and rear

tractor wheels, 1 on each side of the tractor, and

the remaining 3 units trailed behind. This

provided uniform row spacing.

CARE OF THE TRANSPLANT BED

A lack of moisture immediately following planting frequently results in a high mortality of

transplants. Where overhead irrigation is available, each bed should be sprinkled as soon as

transplanting is completed. If it is not available,

furrow irrigation can be used. The construction

of the furrows for distributing the water should

keep pace with the transplanting operation.

Special attention should be given to irrigation

needs when transplanting is done in the late

summer or fall.

Shallow cultivation of transplant beds is beneficial because it eliminates weed growth and

creates a light earth mulch that improves the

moisture-absorbing capacity of the soil. Usually,

power-drawn cultivators are used. Deep cultivation is not required ordinarily. Mulching to

prevent frost heaving is not needed as a rule if the

nursery is located on sandy soil and the transplanting is completed before the end of the growing

season.

The conifers commonly produced in the Lake

States do not require shading during the time they

are in the transplant beds. Frequent irrigation to

reduce ground surface temperatures and increase

available moisture will bring through the more

sensitive shade-loving species even when grown in

full sunlight.

15 Information supplied by Tom O. Bradley, nursery

manager, Soil Conservation Service nursery, Zanesville,

Ohio.

84 Agriculture HandhooJc 110^ Ü. S. Department of Agriculture
HARDENING-OFF

Stock for fall planting must be properly hardened-off. Hence, irrigation should be curtailed

during the late summer to hasten this process.

(See Improving Drought Resistance by Regulated

Watering, p. 69.) Dormancy can also be hastened

by undercutting the beds in the fall several weeks

ahead of digging. Severing the deeper roots, and

slightly disturbing the soil, increases evaporation

of soil moisture and retards intake of water.

Schneider (139) noted a strong color change from

green to purple within 4 days of undercutting

1-0 jack pine. Ponderosa pine may react similarly.

Seedlings, particularly conifers, are considered

to be hardened-off when the terminal buds have

formed and the stem and root tissues have ceased

growth. Other characteristics that indicate dormancy are color and stiffness of the needles.

This is particularly true of jack pine, the needles

of which often take on a dark purplish cast and

increase in stiffness as the plants enter the dormant stage. However, those of southern origin

(44^ to 45° latitude) tend to show much less color

change than those of more northern origin (46*^

to 48*^) under normal hardening-off procedures.

This is illustrated by a comparison of the degree

of color change in 30 different lots of jack pine

grown in the middle of the latitudinal range of

the species in the Lake States at Hugo Sauer

Nursery, Rhinelander, Wis. The seed was collected over practically the entire range of the

species in the Lake States. A substantial increase

in percent of total foliage with the bronze or purplish color (deemed to signify hardening) occurred

in 2--0 jack pine between October 20 and November 4, 1953. But 1-0 stock showed a more complete color change than 2-0 stock, especially for

the stock grown from seed collected between the

44th and 45th parallel of latitude (fig. 51). The

following spring, April 19, 1954, the same lots of

stock showed a color curve almost identical to that

of November 4, 1953 ; this indicated that no change

had occurred due to further subjection to cold in

the 5-month period.

Color change in some of the stock carried to

3-0 age was less complete than at the 2-0 age,

with a straight-line relation extending from 18

percent at latitude 45° to 73 percent at latitude

48° by November 8, 1954.^^ Small lots of the

same stock transplanted at about 8- by 2-inch

1*^ Latitude gave better correlations with color change of

this jack pine than any of four other criteria. On this

set of observations the correlation coefficient was 0.830,

significant at 1-percent level. When related to degree days

over 50° F., it was 0.682, significant at 1-percent level.

When related to average January temperature, it was 0.511,

significant at 5-percent level; and when related to number

of days of frost-free period, it was 0.094, a nonsignificant

correlation. The proximity of large lakes (Lake Superior,

Lake Michigan, and Lake Huron), which have an extending effect on the number of frost-free days, apparently

interfered with the prospect of positively correlating

color change and length of frost-free period of the area of

origin of the parent trees.

Forest Nursery Practice in the Lake States

spacing in the spring of 1954 and observed at the

2-1 stage in the fall of 1954 showed no color change

in any of 10 transplanted lots on October 18, and

moderate color change on November 8, 1954, with

a straight-line relation of 0 percent at latitude 44^

and 20 percent at latitude 48°.

Apparently, latitude of parent trees, as well as

class of stock and length of the hardening period

when plants are subjected to cool temperatures,

may have an effect on coloration and hardeningoff of conifers.

—

^^^

A:

/-

— 7 —

7

4/

1 ! I

LATITUDE OF PARENT TREES (DEGREES)

FIGURE 51.—Effect of latitude of parent trees on relative

completeness of fall color change from green to bronze in

needles of 1-0 and 2-0 jack pine grown in the Hugo

Sauer Nursery, Rhinelander, Wis., which is at approximately 45.65° N. latitude. Thirty seed sources were

involved. Correlation coefficients (r) for the 3 lots

from top to bottom on graph are 0.684, 0.874, and 0.819,

respectively. All are significant at odds of 99 out of

100.

Hardwoods enter the dormant stage with the

occurrence of low temperatures and are dormant

after the first few frosts, or after the stock has

shed its leaves. Harvey (67), for example, noted

that exposure of American elm seedlings for 5 days

to a temperature of 32° F. hardened them sufficiently so that none were killed when later frozen

at 21° for 24 hours. Since deciduous seedlings do

not remain dormant very long after warm weather

sets in in the spring, it is advisable to dig them in

the fall and heel them in overwinter. This practice

also helps to equalize the nursery workload between fall and spring.

85
SPECIAL PROPAGATION METHODS

Practically all stock for reforestation purposes

in the Lake States is grown from seed. However,

certain species used in windbreaks and shelterbelts, and in some research work, are propagated

by cuttings or by grafting.

DORMANT STEM CUTTINGS

The species most likely to be propagated from

dormant stem cuttings in Lake States nurseries

are cottonwoods and willows. Such cuttings

should come from relatively young plants, or

from the sprouts of plants that have been cut

back 2 to 4 years earlier. One- or two-year-old

wood is preferred. In the fall, 3- to 5-foot switches,

Yu to K inch in diameter, are cut out with sharp,

long-handled, pruning shears, or a heavy, sharp

knife. These switches are tied in bundles, covered

with a canvas, sacking, or straw, and taken to a

shelter where they are made into cuttings.

A fast method of preparing cuttings is for one

man to assemble the switches in bunches of 5 to 8,

with the butt ends matched. He then holds them

one layer deep on a wooden block, and a second

man chops them into lengths of 10 to 12 inches

with a sharp cleaver or machete, or a weighted

knife dropped in slotted guides. Cuttings of

substantial size should be discarded, and the buds

of the ones retained should all point in one direction. Those of acceptable grade are counted into

bunches of 50, or any other convenient size, and

tied twice with binder twine at a point 2 to 3

inches from the ends. They are then buried in

moist sand in a pit or root cellar until spring.

In April or May the cuttings are set out in standard trenches about 9 inches deep. One or two

buds, or 2 to 3 inches of cutting, should remain

aboveground. The trench is then closed with a

mechanical packer that is pulled by a rubber-tired

tractor, or, in a small-scale operation, by walking

along the trench and caving it in and firming the

cuttings by heel action. Heavy watering is

required to get good rooting.

The various species of cottonwoods as well as

willows (especially white willow and one of its

hybrids) are readily propagated in this manner

and are ready to ship as 1-0 rooted cuttings by

fall or the following spring, Eooted cuttings at

1 year of age will be sturdier and larger than

1-year-old cottonwoods or willows grown from

seed; in fact, they will be about as large as 2-yearold trees of seed origin.

Cuttings are sometimes planted in the nursery

in the fall (47). Survival of such plantings has

been improved under prairie and plains conditions

by setting a cutting so that only about 1 inch

protrudes from the ground, and then completely

covering it over with a ridge of soil a few inches

deep. This covering prevents excessive drying

out of the cuttings overwinter. The following

spring, the shallow ridge of soil is removed to

uncover the end of the cutting. Cuttings can be

set about 1)2 to 2 inches apart in the nursery.

Use of growth substances may increase percent

of rooting. Soaking the bottom ends of cuttings

in a 50- to 100-parts-per-million solution of indoleacetic acid for 18 to 24 hours before planting (167)

will increase the percent of rooting of the more

easily propagated poplars and willows.

Quaking and bigtooth aspen are very difficult to

root without treatment but are reported to root

well when taken in March and treated with 10

parts per million of indolebutyric acid for 27

hours (167).. Several hundred other species and

varieties of plants can be propagated more readily

by such chemical^ treatment (99^ 167, 185).

Normally, however, few of them will be grown

in forest nurseries.

ROOT CUTTINGS

Shipmast locust, a variety of black locust, can

be propagated by root cuttings. Swingle (165)

recommends taking 3- to 5-inch-long cuttings,

)i to \){ inches in diameter, from roots of young

trees and from younger parts of the root systems

of old trees. The cuttings are taken while the

trees are dormant, and they can be planted in the

nursery any time before bud growth starts. Roots

must be kept from freezing. A sandy soil, or a

mixture of sand and peat in a greenhouse culture,

makes the best rooting medium.

Root cuttings of aspen have also been tried but

the percent of survival was very low. Wildings,

or root cuttings with a small aboveground shoot

of 1- to 2-foot length, have given better survival.

GRAFTS

Grafting is used in forest nurseries for very

special purposes only. For example, grafts have

been used in propagating strains of white pine

resistant to blister rust (120). As forest products

increase in value and as certain prized species

become more scarce, it is quite likely that certain

species, strains, selections, or hybrids will be

propagated vegetatively for mass production.

In grafting, a 3- to 4-inch-long scion of the desired species is joined onto a potted tree of the

same genus: A slit is made in the 2- or 3-year-old

stock, the scion is placed in the slit and wrapped,

and the two join and grow together. Grafting

work is done in January, February, or March in

the greenhouse and the potted grafts moved outside in late spring. Once completely healed over,

usually at the end of 1 year, the top of the ^^stock''

plant is cutoff (56, 83).^

Norway spruce often is used as a grafting stock

for spruces, although white spruce is used occasionally. Scotch pine is used for two-needle pines,

pitch pine for three-needle pines, and eastern

white pine for the five-needle pines. For larches,

European larch is satisfactory.

86 Agriculture Handhooh 110^ Ü. S. Department of Agriculture
NURSERY PROTECTION

Constant vigilance is necessary if serious losses

from nursery injuries are to be avoided. The

early discovery of injury is quite as important as

prompt treatment. Often it is desirable to have

spray equipment and necessary chemicals and

supplies on hand before trouble starts. The

major sources of injury and some of the minor

ones are described in this section. Formulas for

preparing large quantities of insecticides and baits

are given in the appendix, p. 120, and the safety

rules and precautions for handling, mixing, and

applying chemicals, p. 118, should be carefully

observed.

UNFAVORABLE WEATHER

CONDITIONS

Trees in nurseries require protection against

wind, excessive heat, drought, freezing, frost

heaving, drowning, and water erosion. Prevention

of losses from these causes are discussed in detail

in the sections on Seedbed Preparation and Sowing, p. 59; Soil Moisture and Irrigation, p: 67;

Seedbed Care During Germination and the Seedling Stage, p. 71; and Transplanting Operations,

p. 79.

MAMMALS AND BIRDS

Practically all nurseries are so situated that a

fence is necessary to exclude either domestic

livestock or larger wild animals such as deer. If

deer are a problem, a fence at least 10 feet high is

necessary.

Snowshoe hares and cottontail rabbits may cause

damage in Lake States nurseries, especially to

oak, elm, and certain pines, and in western

and southwestern Minnesota, jackrabbits are a

problem. A 4- or 5-foot-high wire fence of 1- to

2-inch mesh will exclude rabbits except where

there is deep snowfall or heavy snowdrifting.

In such areas, the fence should be 6 feet high.

The fence generally needs to be buried at least 6

inches in the ground where the cottontail rabbit

is the offender. Occasional winter checking is

necessary to determine whether rabbits have

gained entrance and are doing damage. If they

have, they can be eliminated by snaring, trapping,

or shooting.

Pocket gophers occasionally cut off tree roots

below the surface. Eegular pocket gopher traps

or a poisoned bait, such as diced, fresh carrots

dusted with powdered strychnine alkaloid at the

rate of ji ounce of powder to 4 quarts of carrots,

are effective controls. When poisoned bait is

used, several placements should be made in each

burrow system, and care should be taken in reForest Nursery Practice in the Lake States

plugging the placement holes to avoid covering

the bait.

Moles, chipmunks, and squirrels occasionally

dig up or eat seed in some nurseries. The hardware cloth screens used at time of seeding to

prevent bird damage give some protection against

these rodents. However, they often dig under

the bedboards or somehow slip past the barrier.

They can best be eliminated by shooting or trapping, or by carefully placed poison baits put out

some weeks in advance of the seeding.

Many species of white-footed mice (Peromyscus

spp.) may eat seed of conifers as well as of hardwoods. The meadow mouse (Microtus) also eats

seeds; and the pine mouse (Pitymys) may do

damage by girdling bark or cutting oiï small

seedlings. Mice can be trapped easily with

ordinary snap traps that are baited with apple,

a vegetable, or oatmeal and placed in runways

and near entrances of burrows. However, poisoned

baits are probably the cheapest and most effective

way of eliminating mice and some of the other

seed-eating rodents. The principal poisons used

are strychnine alkaloid and zinc phosphide.

Inside the nursery, bait stations should be

located at intervals of about 100 feet and staggered

somewhat where bedboards tend to confine and

channelize rodent movement. Outside, bait should

be placed along the fence and in a bordering zone

about 200 feet beyond the fence. In this zone,

especially if it is grassy, bait should be spaced as

close as 30 feet apart, in 4 lines paralleling the

fence, at intervals of about 50 feet. Bait remains

effective somewhat longer if placed in small tin

cans laid on their sides with the opening on a

slight downslope to exclude rain. Do not place

bait where livestock will have access to it.

Nurserymen with rodent problems may wish

to write to the Pish and Wildlife Service, U. S.

Department of the Interior, Washington, D. C,

for the address of the poison-bait distribution

center nearest to them. Prepared baits are available at such centers, and prices vary. County

Agents also may be able to furnish information

about distribution centers. An alternative to the

purchase of prepared baits is to use one of several

formulas recommended by the Fish and Wildlife

Service (5^) and make them up at the nursery.

Two poison-bait formulas for mice are given in

the appendix on p. 120.

Seed-eating birds can be excluded by hardware

cloth screens or by patrolling the nursery in daylight hours during the critical germination period.

Recent costs of using bird watchers who patrolled

on foot with a shotgun have come to 8 cents per

thousand trees. In a large nursery, a bicycle

patrol may be necessary to give rapid enough

coverage of all areas.

87
NURSERY DISEASES

Disease control, according to Hartley {64) is

largely a matter of prevention by proper selection

of nursery sites and species, and attention to soil

condition, stand density, and sanitation. However, in spite of all reasonable precautions, some

diseases are almost certain to be a problem in

every nursery at one time or another.

Damping-Off

Probably the most serious disease in most

Lake States nurseries is damping-ofï caused by

fungi that attack the small, newly germinating

seedlings just before or just after they emerge

from the ground. The stems or roots of the seedlings decay. This disease is especially associated

with conifers, and only the genera Thuja, Cwpressus, Juniperus, and Chamaecyparis are somewhat

resistant to it (10).

Hartley (63) identified various species of the

genera Pythium, Rhizoctonia, and Fusarium as

causal organisms of damping-ofï and suggested

various acidification treatments of soil as a control

measure. In Wisconsin nurseries, Pythium and

Rhizoctonia are the two fungi that have caused

appreciable economic loss, especiall}^ of red pine

stock. Species of the genera Cylindrocladium,

Phytophthora, Botrytis {62), and possibly Alternaría, also cause losses.

Damping-off is favored by the use of poorly

rotted manures, dried blood, or materials that

increase the carbon-nitrogen ratio of the soil {65),

The disease is also favored by materials that decrease acidity, such as lime, limy sand, wood ashes,

or nitrates, or by the use of irrigation water that

has a hardness of over 100 parts per million as

CaCOa or 125 parts per million as a bicarbonate

{39). Damping-off fungi may be introduced by

shipping in infected nursery stock from distant

nurseries.

The usual method of controlling or reducing

the incidence of damping-off is to treat the soil

with Ke to % fluid ounce of concentrated acid per

half pint or pint of water. However, the amount

of acidifying material to apply depends largely on

soil texture and its pH before treatment, as

discussed in the section on Soil Management,

p. 41. Dilute sulfuric acid is applied immediately

after the seed is sown, and the beds are then

watered. The treatment is most effective against

Pythium, which thrives in neutral to slightly acid

soils and in cool-temperature and high-moisture

conditions. If Rhizoctonia is still a problem after

such treatment, formaldehyde or mercuric and

other dusts should be used. Roth and Riker {129)

observed that Rhizoctonia is not inhibited by

relatively acid conditions. Soils with a pH of 5.2

or less generally need no treatment for damping-off.

A study by Wilde {189) indicated best nursery

survival of red pine seedlings when sulfuric acid

was used at or near a 2.0 to 2.5 percent concentration by volume. He suggests application at the

rate of 7 gallons per 100 square feet of bed area in

fall treatment and cutting the concentration to

1.5 percent in spring treatment.

In 1937 Barton ^'^ observed that spring acid

treatment of fall-sown white spruce was very

deleterious. Density per square foot was reduced

from 57.5 trees in fall-treated and fall-sown beds

to 29.0 trees in spring-treated fall-sown beds. In

this case there was no doubt of acid injury in

spring treatment of fall-sown beds because of the

softening of the seedcoat which had occurred in

the period between sowing and treatment.

Rindt {122) used one-sixteenth avoirdupois

ounce of aluminum sulfate per square foot as a

control. The sulfate was mixed in a tank and

then applied through the overhead lines for 20

minutes by using a sump pump. Other authors

have recommended that where there has been no

previous experience with aluminum or ferrous

sulfate preliminary tests be made by actually

trying treatment on a few square feet of soil {39).

The pH value of the soil should then be determined

3 days later. The amounts to be used in such a

test are given in table 32.

Hydrochloric acid has been used in some nurseries but is more expensive than sulfuric acid and

the amount required is roughly 3 times as great.

For phosphoric acid, about 2 K times as much

volume is needed as for sulfuric acid, or about twothirds of the recommended number of avoirdupois

ounces of sulfate.

Acetic acids have been used with success at

one-half fluid ounce per square foot of seedbed,

applied 5 or 6 days before seeding {43).

TABLE 32.—Amount {avoirdupois) of aluminum

sulfate or ferrous sulfate to test on soils of varying

pH where there has been no previous treaitment ^

Amount of sulfate for—

Initial pH

Sandy soil Heavy soil

Per

square

foot

Per 1,000

square

feet

Per

square

foot

Per 1,000

square

feet

5.0

Ounces

0

1.0

1%

Pounds

0

15.6

23. 4

31. 2

46.9

62. 5

78. 1

Ounces

\

I

1.0

1/2

Pounds

15. 6

5.5 23.4

6.0 31. 2

6.5 46. 9

7.0 62. 5

7.5 - 78. 1

8.0 93. 7

Source: Fed. Security Agency, Civ. Conserv. Corps

Forestry Pub. 9 {89).

1 3 days after test treatment of a few square feet of soil :

if top )4 inch of soil has a pH value below 4.0^ treatment

is too heavy; if above 5.0, it is not heavy enough.

1^ Unpublished annual report, Hugo Sauer Nursery.

1937.

88 Agriculture Handbooh 110^ Ü, S, Department of Agriculture
Deep treatment with sulfur to a depth of 6 or 8

inches, using ji to K avoirdupois ounce per square

foot, has value as a damping-off control in alkaline

prairie soils. To avoid acid injury, it should be

applied several warm months or a full year before

seeding.

The repeated acidification of a nursery seedbed,

particularly with aluminum sulfate, has the disadvantage of sometimes causing the caking or

crusting of the soil surface, and it may kill or

stunt the root tip of the seedlings. Hence, other

treatments may be preferable. One of these is

Ye fluid ounce of commercial 40-percent formaldehyde per pint of water per square foot of seedbed.

This solution is applied 4 to 10 days before seeding

and then heavily watered (39). The shorter

period is sufficient in warm weather or on soils

with abundant humus, while the longer period is

necessary in cold, damp weather, or on heavier

soils.

One hour's sterilization with steam at 6 to 8

pounds pressure has controlled damping-oiï successfully in seedbeds (137). The seedlings were

better in the treated areas, and weeding costs were

reduced 82 percent. The disadvantages of steam

sterilization are its lack of adaptability to large

nurseries, its costliness, and its adverse effect on

soil structure.

Other methods for controlling damping-off include applications of chemicals containing copper

and zinc and of mercuric compounds to the seed

or as soil dusts before or after seeding. It is

expected that soil acidification soon will be supplanted by these recently developed fungicides in

nurseries in the forested parts of the Lake States

where the soils are naturally acid. Soil acidification

will, however, continue to be of use in prairie soils

or in certain nurseries where alkaline waters tend

to build up soil alkalinity and create a problem in

seedling nutrition.

Seed dusts of Orthocide 406 (N-trichloro

methylthio tetrahydrothalimide) and copper carbonate reduced damping-off and increased emergence of pine and spruce seedlings (163). Other

chemicals were nearly as effective. These dusts

were applied dry just before seeding in sufficient

amounts to coat the seed.

Soil dusts applied before seeding show promise

of more prolonged protection than that obtained

from seed dusts. Tests of several soil dusts indicated that the following were the most promising

(163): Tersan (wettable tetramethylthiuram disulfide),^^ experimental fungicide 5400, 31 parts of

Ceresan M (ethyl mercury p-toluene sulfonanilide)

plus 1 part of potassium iodide, and Manzate

(manganese ethylene bisdithiocarbamate).

These fungicides were mixed with soil and

applied to the seedbeds as dust—150 pounds per

acre—at the same time the commercial fertilizers

were applied. The seedbeds were then tilled to a

1^ In earlier tests (1^1) Tersan was effective as a soil

dust when used at the rate of 1.2 to 4.8 grams per square

foot. The heavier treatments were best.

Forest Nursery Practice in the Lake States

depth of 5 inches with a rototiller. Treatments of

300 pounds per acre were even more effective, but

it is questionable whether the slightly improved

stands warranted the increased cost. Treatment

with these dusts should be made 3 days before

seeding; if rain occurs, seeding should be postponed

for 6 days.

Effective post-seeding treatments were Tersan,

Crag fungicide 5400, Orthocide 406, Agrox (phenyl

mercury urea), Manzate, and Semesan (hydroxymercurichlorophenol) applied at 150 pounds per

acre in 3 separate 50-pound treatments at 1-week

intervals, beginning 1 week after sowing {163).

The pelleting of seed, using Arasan (50 percent

tetramethylthiuram disulfide) with 4 percent

methyl cellulose as a binder, is reported to be more

effective than treating the soil {12). For every

pound of seed used in fall sowing, there were used

8 ounces of fungicide and 3 ounces of methyl

cellulose, mixed in a pharmaceutical pill coater.

In spring seedings, the fungicide was reduced to

2 ounces and binder to 1 ounce per pound of seed

treated.

In southern nurseries, the spread of damping-off

has been arrested by treating the affected patches

and a border 1 to IK feet beyond them with

Semesan at one-tenth ounce per pint of water per

square foot. Treatments were made on cloudy

days or in the late afternoon to avoid seedling

injury. Top damping-off by RhÍ2octonia, occasionally affecting white pine, can be controlled by

applying Semesan and 4-4-50 bordeaux at the

rate of 1 gallon per 100 square feet of seedbed {39).

Other indirect controls of damping-off include

use of new soil; favoring fall instead of spring

seeding; sowing for lower seedbed densities;

using clean, nonalkaline sand as seedbed cover;

and removing half-shade in periods of prolonged

damp weather.

Acids and sulfates are best applied in solution

from an acid cart by going over beds twice,

that is, reversing direction of application on

the return trip. This equalizes applications per

square foot over the entire bed. Safety measures

for handling acids and sulfates are given in the

appendix, p. 118.

Acid carts often are made of wooden barrels

that are equipped with lead pipe tapped at intervals of 2 to 3 inches and extending across the bed

(fig. 52). The carts can be hand-drawn or pulled

by a light, rubber-tired tractor. Larger nurseries

in recent years have adopted a rubber-tired acid

cart (fig. 53).

Cedar Blight

Junipers, especially eastern redcedar and its

varieties, sometimes are attacked by cedar blight

{Phomopsis juniperovora), particularly in nurseries

in the southern part of the Lake States. Good

results have been obtained by applying standard

bordeaux mixture as soon as growth starts in

the spring and every week thereafter.
FifiURE 52.—Acid barrel

used immediately after

seeding for applying dilute sulfuric acid as a

damping-ofî control.

(Beal Nursery, Mich.)

In trees affected by cedar blight, the tops,

particularly new needle growth, turn gray and,

unless arrested, the infection may spread until

the trees die. Heavy fertilization, high seedbed

density, and humid weather tend to accelerate

the spread of the disease.

Infected seedlings or transplants should be

destroyed by burning. Once cedar blight is

brought into a nursery on diseased stock from

another nursery, it is virtually impossible to

eradicate the disease completely. Hence, it is a

good policy for nurserymen to grow their own

juniper stock.

Leaf Diseases

Among the trees frequently affected by leaf

spot diseases are the ashes, cherries, poplars, and

willows (39).

In ashes, Marssonia fraxini first appears on the

upper leaf surface as small, gray dots. These

enlarge gradually to make larger patches. On

the lower sides of the leaf, small round pustules

appear that develop light gray masses of spores.

The disease causes premature defoliation and retards normal growth.

On cherry leaves, Coccomyces lutescens causes

light yellow to reddish-brown circular spots that

die. The spots may drop out, giving the appearance of a "shot hole."

Poplars and willows often are infected by an

orange-colored rust (Melampsora spp.). Poplars

are sometimes affected by Septotinia spp. that

cause gray or brown blotches with concentric

circles on the upper leaf and white spore masses

of the imperfect stage on either surface.

Leaf diseases generally can be controlled with a

4-6-50 bordeaux spray. The first spraying of

the season on cherries should be cut in strength

to 2-3-50 because of early-season sensitivity of

the species. Lime sulfur spray at 2-percent

solution has been effective in controlling leaf

rusts on ash. Many of the rusts have alternate

host plants which if eliminated will solve the

problem. The advice of a plant pathologist

should be sought to determine the feasibility of

this practice.

Occasionally, certain rusts (Coleosporium spp.)

cause orange to whitish pustules on the needles

of pines in Lake States nurseries. Another rust

(Chrysomyxa spp.) sometimes attacks spruces,

especially black spruce and blue spruce. Ordinarily, these rusts do little or no permanent

damage in the Lake States area. If the marketability of the stock in commercial nurseries is im90 Agriculture Handbook 110, Ü. S. Department of Agriculture
_.a—1

SPRIMKLER DETAIL

(FROM REAR)

A -- 2 X 4

B= I X 7

C -- I X 3

D = I X6

E =2X6

FIGURE 53.—Details of lead-lined acid cart mounted on a tractor-drawn trailer.

paired, a 4-4-50 bordeaux spray is effective

if applied just before the current year's needles

have started to harden.

White Pine Blister Rust

White pine blister rust {Cronartium rihicola)

affects eastern white pine as well as most other

five-needled pines. Normally, it is not a serious

nursery problem. This disease causes cankers

on the central stem or limbs of white pine. A

swelling occurs at the place of infection and its

edges have a yellowish discoloration. At certain

stages there may be reddish-brown spots or scars,

or brightly colored spore masses. As the disease

advances, it partially or completely girdles the

tree and the needles turn a sickly, light-reddish to

reddish-tan color as the affected part dies.

Blister rust is controlled by thorough, systematic removal of the alternate host, that is,

gooseberries and currants (ribes) within 1,200 to

1,500 feet of the nursery. The ribes plants are

pulled up by hand or grubbed out. If concentrated in large numbers, they are treated with

chemicals such as 2,4-D and 2,4,5-T.

Forest Nursery Practice in the Lake States

Rusts of Hard Pines

Sometimes the two- or three-needled pines,

particularly Scotch, Austrian, and ponderosa

pines, and, to some extent, jack pine, are infected

by a gall rust {Cronartium cerebrum) that causes

a round, ball-shaped stem swelling 5 to 10 times

the diameter of the normal stem. On jack pine

the swelling occurs on twigs, small branches, or

the stem. Such trees die when they are set out

in plantations, and they may act as a focus of

infection for spread of the disease to other parts

of the planting {148). Oak is the alternate host

of the gall rust.

In the Lake States, the best way to prevent gall

rust is to avoid planting the more susceptible

species, which, except for jack pine, are not native

to the region. If a nursery produces some of the

susceptible species and more than Xo of 1 percent

of the trees become infected, a pathologist should

be consulted. In some cases control may require

eradication of the alternate host within one-fourth

mile if this is feasible, or spraying the nursery

beds with 8-8-10 bordeaux or lime sulfur. The

latter is generally the more feasible procedure.

91
Control work should start in early July or as soon

as the first telia are formed on the oak host plant.

In central Wisconsin, as much as 25 percent of

the jack pine in a large nursery has been aflfected

by gall rust.

Sweetfern Blister Rust of Pitch Pines

Sweetfern blister rust (Cronartium comptoniae)

is limited to two- and three-needled pines. It

appears especially on jack, Scotch, ponderosa,

and lodgepole pine, but it will also attack others

such as Mugho, Austrian, and red pines. Alternate hosts of the disease are sweetfern and

sweetgale.

The disease may attack seedlings and trees up

to 2 inches in diameter (I48). It causes a swelling

near the soil surface, and the girdling action often

is sufficient to kill the tree. On occasion, the rust

has caused heavy losses in Lake States nurseries,

particularly of ponderosa and lodgepole pine,

neither of which is native to the region. In each

instance, there was considerable sweetfern on

areas surrounding the nursery.

In late May and early June infected trees

develop white blisters filled with orange or yellowish spores. On older cankers, however, blisters

are scarce or even absent. There is considerable

resin flow from ,the infected parts that are sometimes twisted or flattened (61).

Nurseries in which the more susceptible species

are to be grown should be located at least onefourth mile from scattered sweetfern and sweetgale. Susceptible species, particularly those not

native' to the region, should not be planted in or

near areas where the alternate host is present.

Infected nursery trees should be destroyed.

Eradication of the alternate host may be feasible

in the vicinity of established nurseries.

Nursery seedlings or ornamentals can. be protected by spraying them with bordeaux mixture

(8 pounds copper sulfate, 10 pounds hydrated

lime, and 2 pounds calcium casein ate in 100 gallons water) from about August 1 until the onset

of frost. A lime sulfur spray, consisting of 2.5

gallons liquid or 6 to 8 pounds dry material in

100 gallons of water, is also effective (61),

Snow Mold

On occasion, an especially deep or long-persisting snow mantle pressing down on the trees may

cause damage to spruce, balsam fir, and occasionally pines by promoting growth of a snowmold fungus (Phacidium infestans) {39).

Dormant-strength lime sulfur sprayed as soon

as the trees are dormant in the early fall is recommended as a precautionary treatment in nurseries

where such damage has been noted (39). A Fermate spray also has given good control. Treatment will prevent transfer of the fungus to the

field. In beds affected by snow-mold fungi, the

needles are glaucous brown and, by fall, dark disklike bodies containing spore sacs appear on the

underside of the needles. Complete mortality of

trees may occur in patches up to 2 feet or more

in diameter. As the trees are exposed by snow

melting, there is a covering of white mycelia oii

the brown foliage (17).

Molds or Rots in Storage or Transit

Nursery stock may be damaged by heating and

molding in storage or in transit if kept too long

in tight bundles. Proper control involves reducing the period of time between lifting and cold

storage, keeping storage temperatures low, using

properly prechilled packing materials, and trucking the stock in overnight shipments.

In discarding damaged stock, care should be

taken to distinguish between actual rots as shown

by a sloughing of roots, and superficial or harmless molds on the stems and mycorrhiza on roots.

Rots of Seed in Beds

Seed may rot in waterlogged or flooded beds

in localized low or poorly drained spots. The

best measure is prevention through selection of

soils with good surface and subsurface drainage

or raising the seedbeds above the general level

of the paths. Proper seed pretreatment is

helpful because prompt germination reduces the

chances of the seed rotting. Removing shade

frames is necessary where the seedbed surfaces are

too moist.

Root Rots

Trees with rather thick, fleshy roots, such as

black walnut, black locust, and the oaks, are subject to root rots (Phytophthora spp.), especially

on heavy, wet soils or on areas used repeatedly

for production of the same species. Siberian

elm also has been damaged in indoor winter

storage or when heeled-in outdoors in unfrozen

ground.

The root rot problem is accentuated by growing

fleshy-rooted species to large-size or old-age

classes. In digging, the long taproots are severely

mangled and may rot in the heel-in bed. Root

rot in Lake States broadleaf species is controlled

best by proper rotation, and by using welldrained soils, changing heel-in beds, and producing

1-year instead of 2-year stock.

Since root rot has not been a serious problem in

Lake States nurseries, controls have been tested

on only a small scale. It may be necessary, however, to try them on an expanded scale if losses

become severe. In southern nurseries, ethylene

dibromide has given good results in control of

root rot of pines, probably associated with

nematodes. It is applied at the rate of 25

gallons per acre 2 to 3 weeks before sowing. It.

may be diluted in 100 gallons of water per acre

for greater ease of application. A hand appli92 Agriculture Handhooh 110^ TJ. S. Department of Agriculture
cator, such as a Mack Weed Gun or a Fumi-Gat,

is satisfactory for small-scale treatment. For

large-scale treatment, a commercially available

soil-injection kit is desirable (69). This consists

of a lift on the rear of a rubber-tired tractor

equipped with adjustable shanks for lateral

spacing. On the back of each shank, tubes

leading down to near the tip convey the chemical

under pressure from a 50-gallon drum attached

to the rear of the tractor. Methyl bromide

and chloropicrin were also successful in combating

root rot (69). In trials at Chittenden Nursery,

Mich., the former has given the best results,

but sufficient tests have not been conducted to

justify definite recommendations.

Cedar-Apple Rust

Large transplants or large ornamental stock

of eastern redcedar and other junipers are susceptible to cedar-apple rust (Gymnosporangium

juniperi-virginianae). The disease causes unsightly, brown galls that develop long, orangecolored spore horns in the spring. The disease

passes to apples and hawthorn and back to

juniper. In some States where apple growing is

an important industry, regulatory laws require

eradication of redcedar. Where it is necessary

to grow eastern redcedar or other susceptible

junipers, it is recommended that they be kept

at least one-half mile away from the alternate

host.

Cedar-apple rust also can be controlled by

spraying junipers with bordeaux 180 (12 pounds

copper sulfate, 12 pounds hydrated lime, 2

pounds mono-calcium arsenate, and 8 pounds zinc

arsenate in 100 gallons of water with spreader)

in the spring when the telial horns are no longer

than one-fourth inch. This arrests their further

development (60).

Elgetol applied as a spray at 1 gallon per 100

of water also has given satisfactory control,

especially when applied during the spring when

the telial horns are small.

Ferbam-sulfur applied in 3 sprays at 3- to 4-

week intervals starting in early June will control

the rust. It is made up of K pound ferbam and

3 pounds of microfine, wettable sulfur in 100

gallons of water. Ferbam-sulfur also can be

applied to the apple and hawthorn hosts 4 or 5

times at 7- to 10-day intervals, beginning in the

spring when the telial horns first appear on the

junipers.

Actidione (cyclo-heximide) at a concentration of

100 parts per million has shown some possibilities

as a spray to prevent teliospore formation, in

tests conducted by Forrest Strong of Michigan

State University.

Needle Cast

Needle cast may attack balsam fir, Norway

spruce, Douglas-fir, tamarack, jack pine, red pine,

Scotch pine, eastern white pine, ponderosa pine,

Forest Nursery Practice in the Lake States

408189°—57 7

and several conifers not grown in the Lake States.

There are a number of species of fungi that cause

the disease, including Lophodermium pinastriy

Hypodermella ampla^ Elytroderma deformans, and

Bifusella linearis.

Needle cast, as the name implies, involves more

or less heavy loss of foliage. Needles 2 years of

age or older are discolored, become yellowish or

brown in late spring or summer and, in severe

cases, may drop off leaving only the first-year

needles on the tree. Tiny, black, shiny, elongated,

fruiting bodies may occur at early stages on the

needles.

The disease has been controlled by spraying

nursery beds with 2 percent lime sulfur with

sticker, or 4-4-25 bordeaux mixture. Spraying

is started when new needles are about half grown

and may have to be repeated a number of times,

particularly after rains, until growth ceases (17).

Cytospora Canker of Poplar and Willow

This fungus is very prevalent on the bark of

poplars, willows, and mountain-ash. It may

become serious when plants are injured or bruised,

as by hailstones or by ice damage. It may occur

on wildings growing on sandbars along streams.

The disease may also affect cuttings lined out in

the nursery or heeled-in with part of the bundle

exposed. Damage in plantings is accentuated

when the trees are planted on poor or dry sites,

or in weedy situations where tree vigor is adversely

affected. High vigor appears to be important in

creating resistance to the disease.

On young, smooth-barked shoots the young

infection causes brownish, shrunken patches. The

cambium is gradually discolored and killed and

the diseased portions may encircle the plant (17).

Cuttings should be kept in cold storage at about

35° F., and any bundles heeled-in should be buried

completely to avoid infection in cut ends.

When lining-out cuttings in the nursery, nurserymen can reduce infection by completely burying

the cutting or putting a ridge of soil over the

cutting until rooted. Abundant watering will

maintain high vigor and thus reduce losses,

especially early in the season. Nursery stock or

cuttings from an infected nursery should not be

moved to new nurseries. Some nurserymen dip

freshly prepared cuttings in a 1-percent solution

of Semesan or a 2-percent solution of Ceresan M

before lining them out.

NURSERY INSECTS

Insects may cause serious damage in nurseries,

and frequent checks are necessary to catch damage

in the early stages so that prompt remedial

measures can be taken. Fortunately, great strides

have been made in recent years not only in the

general knowledge of insects and their life histories

but also in the development of new insecticides.

Various types of insecticides are available for

control of insects. The stomach insecticides are

93
used for killing leaf feeders, especially larvae of

moths, beetles, and sawflies. The chief inorganic stomach poison is arsenic in various forms,

particularly as lead arsenate. There are also

good organic forms of insecticides, such as derris,

pyrethrum, and tobacco products. The newer

organic chemicals such as DDT, chlordane, and

benzene hexachloride act as stomach poisons and

also as contact insecticides.

Contact insecticides, as the name implies, kill

insects by contact and are chiefly used to control

sucking insects. Among contact insecticides are

nicotine sulfate, pyrethrum, lime sulfur, sulfur

dust, oils and oil emulsions, DDT, chlordane, and

benzene hexachloride.

White Grubs

White grubs are the larvae of the May beetle

(Phyllophaga spp.) and related genera. They

have killed over a million trees in a single season

in individual nurseries. Damage caused by the

grubs feeding on tree roots is especially serious in

1-0 and 2-1 trees. Virtually all of the conifers

commonly grown in Lake States nurseries, and

broadleaf species such as birches, ashes, and

elms, are attacked.

In the Lake States, white grubs or larvae

require several years to mature. Young grubs

may be ji inch or less in length, and older grubs

may be a full inch. Adults are thick, brownish

beetles ranging from % to 1 inch in length.

By far the most effective method of white grub

control in forest nurseries is the application of 10

pounds of chlordane per acre in the form of 100

pounds of 10 percent dust. It should be applied

with a potato or other power duster before

seeding and then worked into the top 6 to 8

inches of soil by a rototiller or disk (145). Such

treatment will prevent grub damage for about 4

or 5 years. In New York State nurseries, control

of white grubs is obtained by use of paradichlorobenzene at 500 pounds per acre.^^

Areas already occupied by seedlings or new

transplants which are to remain in the ground for

one or more growing seasons can be given an emergency treatment with 5 to 10 pounds of chlordane

per acre. The chlordane is applied in emulsion

form with a soil-injection kit with a sprayer, or

through the overhead irrigation system, at dilutions of 1 to 1,000 or 1 to 1,500. Although such

an emergency treatment is not completely effective, it will kill practically all of the smaller grubs

and some of the larger ones. As soon as the trees

are dug, the infested areas should be treated with

a dust.

White grubs often are very abundant in sod

areas or abandoned fields. If such areas are developed for nursery sites, the chlordane dust treatment should be used before seeding the first crop,

1Ö Personal communication from E. J. Eliason, Supervising Forester, New York State Conservation Department.

especially if counts show the grubs to be fairly

numerous.

Aldrin and benzene hexachloride have been used

effectively against white grubs. County Agents

and State Agricultural Experiment Stations can

provide the most recent recommendations on these

chemicals.

Where vegetation such as oaks or aspens require

protection from the leaf-feeding adult beetles, control can be attained by spraying such vegetation

with 6 percent DDT or with lead arsenate at 4

pounds per 100 gallons of water.

In early control attempts, lead arsenate was

used as a soil dust but often the poison caused

heavy damage to trees, especially on sandy soils

of low organic-matter content. Destruction of

white grubs by rototilling once in June or July

has given a 75-percent kill.

Ants

Ants may damage seedlings by injecting formic

acid into them, burying them, harboring harmful

aphids, cutting the leaves, or cutting them off.

Mound-building ants can be eliminated by applying 2 ounces of 50 percent wettable chlordane

powder for every 2 feet of mound diameter. The

chlordane is best applied by first mixing each 2

ounces with 1 pound of sawdust or % pound of dry

sand as a carrier (14^). An alternative is to punch

holes in the mound with a broomstick and pour in

carbon disulphide at the rate of 1 pound (or 1 pint)

per 2 feet of mound diameter and plug the holes.

The best time for treatment is late fall or early

spring.

Ants can also be eliminated by using a poison

bran bait made up with 2 pounds of sugar and 8

ounces of honey dissolved in 1 quart of boiling

water, with 125 grams of sodium arsenate or 60

grams of thallium sulfate mixed into the syrup

while hot. This is poured over and mixed with

the bran, then scattered near the ant workings.

Strawberry Root Weevil

The strawberry root weevil (Brachyrhinus ovatus), sometimes called the conifer root weevil, is

a pest not only on strawberry plants but also on

numerous conifers, such as Norway spruce, ponderosa pine, white pine, red pine, jack pine, tamarack, Japanese larch, white-cedar, and white spruce

(93). The adults are small, black beetles about a

quarter inch or less in length. In the larval stage,

they feed on the seedling roots, denuding them of

their outer layers.

The heaviest damage often occurs in spring of

the third year in the seedbeds. Turner (175) noted

serious damage on 2-0 red pine by a girdle of the

stem just below the ground line. Damage was

worst on poor, dry, sandy areas. It is very probable that the preseeding chlordane-dust treatment

of soil used for control of white grubs will also

94 Agriculture Handhook 110^ ü. S. Department of Agriculture
check or largely eliminate damage from the root

weevil.

For control in situations where the beetles have

emerged, spray the foliage of infested trees with

1 pound of aldrin per 100 gallons of water (108).

Dieldrin, heptachlor, or chlordane may be substituted for the aldrin.

The wingless adults have been controlled by

spreading poison baits in the late afternoon as soon

as the beetles begin to emerge in large numbers,

making three applications a week apart. The

bait may consist of 5 pounds of calcium arsenate

dusted over»95 pounds of ground apple waste; or

20 pounds of bran, K gallon molasses, 1 pound

white arsenic, 3 ounces of oil of apples, and enough

water to moisten the mixture (93),

Wireworms

Wireworms are the long, brown, so-called hardshelled worms, usually with well-developed legs,

that feed in the soil on small roots and other plant

material. They are the larvae of the click beetles

(Elateridae) which, when placed on their backs,

flip into the air. Wireworm infestation can be reduced by keeping land free of weeds. Land not

currently in tree production can be treated by

pouring 1 ounce of carbon disulphide into holes

6 inches deep and 2 feet apart (172),

Grasshoppers

Grasshoppers have been troublesome pests since

time immemorial. During drought years especially, they may strip the foliage from both broadleaf and conifer nursery stock. Grasshoppers can

be controlled with sprays, dusts, or baits.

Sprays may be made up of one of the following

active ingredients per acre: 1^ to 2 ounces aldrin,

K to 1 pound chlordane, or 1 to IK pounds of

toxaphene (110). If dusts are used, the above

quantities should be increased by 50 percent. The

lower dosages are used for young grasshoppers or

where vegetation is short or sparse; otherwise, the

heavier dosages are used. If the nursery stock is

being damaged, it and a buffer strip 100 yards

wide outside the nursery should be treated.

Other chemicals used in grasshopper control are

methoxychlor, dieldrin, parathion, and dilan, but

these should not be used unless specifically recommended by County Agents or the State Entomologist.

Emulsions and oil solutions are preferable to

wettable powder sprays. Not more than 1 gallon

of diluted oil solution is required per acre, using

ground-spray equipment. Treatment is started

when the young grasshoppers begin to move from

their places of hatching.

Baits are made of bran or a bran-sawdust mixture, and for every 100 pounds of this material,

one of the following active ingredients is used: 2

ounces aldrin, 8 ounces chlordane, or 1 pound

toxaphene. The wettable powder or emulsifiable

concentrate is mixed in 10 to 12 gallons of water

and then sprinkled slowly over the previously

mixed batch of 25 pounds of bran and 3K bushels

of sawdust (roughly 3 times the volume of bran).

This bait is used at the rate of 20 pounds per acre,

spread by hand or by a broadcasting machine.

Livestock should be kept away from baits and

insecticides.

Bark Aphids

White pine seedlings and transplants may be

attacked by pine bark aphids (Pineus spp.), insects

native to Europe. Usually, they are first noticed

on the central stem and branches in the form of

white to grayish-white masses of waxen wool that

cover the larvae and adults. Bark lice, or woolly

aphids as they are sometimes called, have been

noted on balsam fir in the Northeast (88) and on

red pine, Austrian pine, Scotch pine, and spruces

(37). In the early spring, just before growth

starts, these insects can be controlled by spraying

with lime sulfur at 1 to 20 parts of water, miscible

oils at 1 to 25 parts of water, or nicotine sulfate

at 1 to 400 parts of water (88). This treatment

will probably be effective on other bark aphids.

Spruce Gall Aphids

The spruce gall aphid (Chermes abietis) is a small,

brownish insect from Ko to Ko inch long. It forms

unsightly, reddish-brown galls K to 1 inch long on

Norway spruce or, sometimes, white spruce. The

conelike galls are formed on twigs at the base of

the current yearns growth and are caused by activity of the female and of the nymphs.

Gall aphids generally are no problem in nurseries

growing only seedlings or transplants, but they

may attack larger ornamental stock or windbreak

trees around the nursery. Spraying may be necessary to prevent disfigurement or even death of

such trees.

Dormant sprays of 1 gallon of miscible oil to 20

gallons of water, or 16 K pounds of powdered lime

sulfur to 50 gallons of water, give good control.

A summer spray of nicotine sulfate at 1 to 800

by volume in water with soap at 1 pound per 25

gallons of water also is effective (115).

Cutworms

Cutworms are larvae of night-flying moths

(Agrotis, Lycophotia, Euxoa, Septis spp.). The

larvae feed on roots of plants and at night may

work above ground on the foliage or may cut off

seedlings at the ground line.

In the late afternoon or evening, poison bran

baits similar to those recommended for grasshoppers should be scattered thinly on the area where

cutworm damage is starting. Dusts of DDT or

chlordane also give effective control.

Forest Nursery Practice in the Lake States 95
Red Spiders

There are a number of tiny spider mites {Tetranychus and Paratetranychus spp.), commonly

called red spiders, which damage nursery stock as

well as older trees by sucking the sap from leaves

and tender stems. The insects are spread by wind

currents, by infested nursery stock, and by crawling from plant to plant. Damage is especially

heavy in dry, hot weather, and on trees of poor

vigor. Frequent sprinkling with water will reduce

damage. Injured leaves are very finely mottled

and turn lighter green and finally brown. From a

distance there is a bronze or brownish cast to the

leaves or needles. Often there may be premature

leaf drop in July. The adult mites usually are

reddish in color except for the spruce mite which

is dark green. Some species of the red spiders spin

a web in summer for protection of young and eggs.

Basswood, oaks, spruces, and hemlock commonly

are attacked.

Red spiders can be controlled by spraying the

nursery stock twice about a week apart with aramite or dimite (53), rotenone, tetraethyl pyrophosphate, or parathion. A good treatment consists of a spray made of 1 pound of cabinetmakers'

or bill posters' glue in 10 gallons of water.

Scale Insects

Many genera of sucking insects known as scales

(Diaspis, Lecanium, Toumeyella, Pulvinaria, Ohionaspisj Aspidiotus, and Physokermes) attack elms,

maples, basswood, birches, ashes, black locust,

oaks, white-cedar, pines, spruces, and junipers.

The insects are small, flat, and oval in shape,

usually ranging from 1/16 to 3/16 inch in diameter.

They fasten themselves to the undersides of leaves

or to small stems. Scale attacks may be observed

as small, white or gray, woolly dots, or by presence

of shiny, smooth, half-shell shapes covered with a

waxy coating.

Scale insects are controlled with contact insecticides applied either when the plants are dormant

in spring or during the growing season. The following sprays may be used in the spring before

growth starts: (1) 2 pints malathion (50 percent

emulsifiable concentrate) in 100 gallons of water.

(2) Lime sulfur at 12 pounds per 100 gallons of

water, or at 5 gallons (liquid form) per 95 gallons

of water {93). (3) Miscible oils or emulsions

applied at about 1 gallon of miscible oil to 20 or

25 gallons of water when the temperature is above

40° F. Pressure should be ample to get good

coverage of the leaves with the sprays.

The recommended summer spray for soft scales

is 1 pint of 40 percent nicotine sulfate in 100 gallons

of water with 4 pounds of ordinary laundry soap

dissolved in it {111). Such a spray should be

applied just after the insects hatch and before they

have developed their protective, waxy cover. Recently, good control has also been obtained with

both DDT and malathion. ^

A spray used effectively on juniper scale is 3

pounds of 15 percent parathion per 100 gallons of

water, or nursery Volck solution at 1 to 24 parts

of water {102).

Tip-Boring Insects

Several insects that bore in the tips of pine and

spruce trees may become a problem largely on

windbreaks or natural trees in or near the nursery.

Among these are the European pine shoot moth

{Rhyacionia buoliana) and the native white pine

weevil {Pissodes strobi). However, these insects

seldom affect nursery stock.

Sawflies

Sawflies are heavy-bodied, wasplike insects, the

females of which have a sawlike ovipositor on the

abdomen. The larvae, or false caterpillars,

usually are K to 1 inch long and defoliate pines and

tamarack, and occasionally spruces, balsam fir,

and northern white-cedar. The most important

species in the Lake States belong to the genera

DiprioUj Neodiprion, and Pristiphora. The sawflies are most likely to be a pest in nursery windbreaks and hedges but may, on occasion, defoliate

larger transplants or ornamentals.

The larvae are controlled readily by DDT,

benzene hexachloride, or malathion. If infestation

is very scattered, only the infected trees or spots

need be sprayed. This can be done most effectively with a knapsack sprayer and an emulsion

prepared from commercial emulsifiablç concentrate

containing 25 percent of DDT by weight; applications of 1 pint of the concentrate to 7 pints of water

should be made at the rate of 20 to 25 gallons per

acre {136). Larger areas" may be treated by hydraulic sprayer, with 2 quarts of the concentrate

in 99.5 gallons of water; the dosage should be 300

to 400 gallons per acre. When applied from aircraft, 1 pound of DDT (technical grade) in 1

gallon of oil solution per acre is also very effective.

A new development on control of the European

pine sawfly {Neodiprion sertijer) is the use of a

spray made up of a suspension of polyhedral virus

in water. Bird {13) reports over 94-percent mortality of sawflies in a 50-acre Scotch pine plantation in southern Ontario within 21 days after

spraying by aircraft, using 22 gallons of virus suspension containing 5 million polyhedra per milliliter. Skim-milk powder had been added to the

suspension as a sticker. Essentially, the same

results were obtained in smaller scale trials with

3-gallon, hand-pressure sprayers. Infestations of

the European pine sawfly in the United States

have also been controlled by airplane application

of a spray containing this virus.

96 Agriculture Handbook 110, Ü. S. Department of Agriculture
Pales Weevil

The pales weevil (Hylobius pales) is a reddishbrown to black snout beetle from ji to % inch long.

It emerges from the soil or from beneath stones in

May and begins to feed. Its eggs are laid around

July 1 in freshly cut pine logs or in large roots of

freshly cut or burned stumps. The eggs hatch

after several weeks and the grubs feed beneath the

bark in July and August. They also feed in

spring. The new generation of adults emerges in

September and feeds until mid-October. It is

during this period that damage may be done in

adjoinmg nursery areas by their gnawing away

the bark of seedlings at the ground line during the

night. White and red pines and Norway spruce

have been attacked by this insect. Hardwoods are

injured only occasionally. As a control measure,

Peirson (112) recommends that no pine land be

used for nursery purposes until 3 years after it is

cleared. On infested nursery stock, a spray of

0.25 percent benzene hexachloride is effective.

Blister Beetle

Adult blister beetles (Macrobasis spp., Epicauta

spp., Pomphopoea spp.) sometimes defoliate nursery

stock of black locust, Siberian peashrub, and other

broadleaf trees and shrubs.

The beetles are of medium to large size, rather

slender, and soft-bodied. They may vary in

color from green, gray, and brown to black (37),

Control can be attained by dusting with 30 to

35 pounds of 10 percent chlordane powder per

acre, or by spraying with 1^ pounds of lead

arsenate to 50 gallons of water.

Cottonwood and Willow Leaf Beetles

Cottonwoods and willows sometimes are defoliated in nurseries by leaf-eating beetles of such

genera as Chrysomela and Plagiodera. The eggs

of these beetles are laid in May or June and in

about a week hatch out larvae that feed on foliage.

These insects can be controlled by spraying the

nursery stock with 2 quarts of emulsifiable concentrate containing 25 percent DDT by weight

in 99.5 gallons of water, or 4 pounds of lead

arsenate per 100 gallons of water. Spj-aying

should be done as soon as defoliation starts.

Red-Humped Caterpillar

The red-humped caterpillar (Schizura concinna)

has defoliated butternut and black walnut in

Wisconsin forest nurseries. Control of these and

many other caterpillars, as well as the larvae of

the elm leaf beetle, may be attained by sprays

containing 1 pound of DDT wettable powder or 4

pounds of lead arsenate per 100 gallons of water.

Nut Weevils

Larvae of certain snout beetles (Curculio spp.)

often eat out the interior of acorns and destroy

their viability. If freshly collected oak seeds are

dumped in water, some of the poor ones float and

can be discarded. The rest may be placed in a

tight container for 24 to 48 hours with a cup

holding carbon disulphide. Four fluid ounces

of carbon disulphide will treat a 100-pound can

of seed.

NEMATODES

Nematodes are tiny, threadlike, soil-inhabiting

worms that injure roots of trees and weaken the

plants. The soil may be treated with either

methyl bromide at the rate of 1 pound per 100

square feet, ethylene dibromide at 25 gallons per

acre, carbon disulphide, or chloropicrin, following

the manufacturer's directions as to the method of

treatment.

MECHANICAL INJURY

Mechanical injury, especially in cultivation, can

cause considerable loss of young seedlings. Such

damage can be reduced by (1) avoiding too early

cultivation, (2) cutting down the number of

drills from 10 to 6 or 7, (3) using shields to prevent

excessive throwing and burial of soil from cultivation tools, and (4) obtaining uniform spacing in the

rows while transplanting.

Considerable damage may also be done in hand

weeding by pulling up trees along with the weeds.

Such damage can be held to a minimum by

removing the weeds when they are small, by the

presowing application of chemicals to kill weed

seeds, and by using mineral or white spirit sprays

that largely eliminate hand weeding.

CHLOROSIS

Chlorosis (pale-colored foliage) reflects a number

of unfavorable conditions such as alkaline soils

or deficiencies of specific elements such as manganese or nitrogen. (See Soil Management section, p. 49.) By correcting these conditions, the

chlorosis usually can be eliminated. For example,

in several instances iron deficiency has been

corrected within a week to 10 days by using a

1-percent foliage spray of ferrous sulfate and then

avoiding washing it off the foliage (39).

Forest Nursery Practice in the Lake States 97
INVENTORY

For proper management each nurseryman must The cost of inventory then amounts to a few

know the number of trees in his nursery by kinds cents per thousand seedHngs if the percent of

and classes. As it is normally impractical to make sample is properly gaged to the overall totals in

complete counts, some adequate sampling method each specific lot of stock, class of stock, seed lot,

must be employed. or season of planting.

Preliminary estimates, often needed for planning Nursery inventory tends to become a tedious

distribution of stocks, are generally made in late task, and the nurseryman will want to select perJune or early July on first-year seedlings. A more sonnel who can count accurately and record the

intensive and more accurate inventory is made in data carefully. He or a foreman may, on ocíate summer or fall, generally to obtain an estimate casion, run an unexpected sample recount on one

within 3 to 5 percent of the actual number of of the sampling units just after an entry is made

seedlings in the various lots. and while the counting frame is still in place.

The intensity of sample taken will be determined Seedbed counts can be made most advantageby the accuracy of count needed, the purpose of ously by a 2-man crew, 1 man working each half

the inventory, the experience gained in past years (or approximately half) of the bed. This does

through comparison of sample inventories with away with having to jump across the bed. The

actual counts of trees shipped or lifted, and the surface of broadcast-sown beds inside of the 4.0-

amount of time and money the nursery has to by 0.5-foot counting frame may have to be marked

devote to the inventory. into smaller units to facilitate counts and avoid

In many Lake States nurseries the sampling duplication or misses. A shallow mark scratched

unit of inventory in seedbeds is a 4.0 by 0.5-foot lengthwise down the approximate center of the

narrow strip across the full width of the bed. The counting strip, and 4 to 6 cross scratches made

area is defined by a frame of wood, wire, or heavy with a nail, increase accuracy of counts. Drilltin with exact inside dimensions. The frame may sown beds are somewhat easier to inventory than

have four steel pin legs which rest in the path or broadcast-sown beds since the former are counted

inside the bed, and which are pressed down, if a drill at a time as the counter moves progressively

necessary, to bring the frame^s bottom well down across the bed.

into the seedlings. Transplant inventory can be accomplished

The number of 4.0- by 0.5-foot sample counts nicely by 1 man doing his own counting and

that can be taken per 8-hour man-day, where tallying on sample transplant rows of 6-foot length

seedlings average around 45 to 50 per square or 4- or 5-foot bed width.

foot, is as follows: Most nurseries use a mimeographed form for

Sample recording inventories. One convenient form lists

Class ofstock {nurHblr) individual secdbcds and groups of 10 beds bel_0 120-160 tween pipelines according to their permanent

2-0 90-120 numbers. It includes block or compartment,

3-0 80-100 section (generally a 10-bed unit between pipelines),

In transplant beds the sampling unit for and bed (generally numbered from 1 to 10 going

machine-planted trees is generally a 6-foot-long from west to east or from north to south). It

section of an individual row. When transplanting also includes date of inventory, length of bed, and

is done across the bed with 4- to 6-foot-long trans- information on species, class of stock, seed source

plant boards, the sampling unit is the individual and lot, and percent of sample taken. Each samrow corresponding to the bed width. In count- pie is shown separately, and a calculation is made

ing transplants a 6-foot wooden pole (or one cor- of total trees in each lot. Many nurserymen also

responding to bed width) with a long, thin nail or find it convenient to record an estimate of percent

heavy 4-inch-long wire bent at right angles to of field-plantable trees or of those suitable for

the pole at each end will serve as a sampler. transplanting in the nursery, so that the total

In transplant inventory, the usual rate of count- inventory may be realistically reduced by the

ing where there are about 30 trees per 6 feet of row estimated percent of cull.

is 160 to 200 samples per 8-hour man-day. Trans- ^ Tables 33 and 34 are presented as a guide for

plants, because of their greater uniformity of inventory of nursery seedlings and transplants,

spacing and per-unit-of-area stocking, require less These tables are so designed that the nurseryman

intensive sampling for the same degree of accuracy has a choice of the sampling intensity he wishes to

than do seedbeds. adopt, but the bold figures are suggested as

98 " Agriculture Handbook 110^ Ü, S. Department of Agriculture
practical. It should be noted that the intensities

of sample needed for nonuniform beds are considerably higher than for uniform beds to be

within comparable limits of error. ^^Error/' commonly referred to by statisticians as ^'standard

error/' implies that the correct value will lie

within the range of the specified error, plus or

minus, in 2 out of 3 trials. When these tables are

used, the total linear footage of each lot should

be the controlling factor. The total number of

seedlings expected is merely a supplemental guide

that assumes a certain average stand per square

foot of normal bed.

Many nurserymen use 10 sample counts per

500-foot bed. This has considerable merit and,

as seen in table 33, would in uniform seedbeds give

estimates within 5 percent of error for any lot of

stock of a total bed length of 1,000 feet or comprising about 180 thousand trees. However, for

an individual bed of 500-foot length, 17 sample

units would be needed to be within 5 percent

accuracy.

As a matter of simplicity, most nurserymen

adopt samples of 1, 2, 5, 10, 15, or 20 per bed. If

only 1 or 2 samples are taken per bed, then the 10

or 20 samples per section (of 10 beds between

pipelines) should be rather carefully distributed

over the entire sampling area of 500 by 50 feet.

This can be accomplished by selecting the 1 or 2

samples at random within each bed.

For a sampling intensity involving 5, 10, 15, or

20 units per bed, the location of the sampling plots

could be determined by pacing. The interval bei*

tween sample plots in each 500-foot bed would be

100, 50, 30, and 25 feet, respectively, for these

sampling intensities. The pacing scheme is a

TABLE 33.—Number oj counting jplots required in inventory of nursery seedlings which will he within specified

limits of error ^

Total

length

of bed

Total

number

of trees

expected ^

Samples required per bed when specified percent of error

Number of

beds In uniform bed is— In nonuniform bed is—

0.5 1 2 3 5 10 1 2 3 5 10 15 20

1 _ _

Ft.

500

1,000

2,500

5,000

10, 000

25, 000

50, 000

100, 000

Thousands

90

180

450

900

1,800

4,500

9,000

18, 000

No. No. No. No.

46

23

9

5

2

1

No.

17

8

3

2

1

No.

4

2

No. No. No. No.

58

29

12

6

3

1

No.

18

8

3

1

1

No.

7

3

1

No.

4

2 - - 50

20

10

5

2

1

1

82

35

16

8

3

1

1

2

5 _

10 __ _- 36

18

8

4

2

20

"Í7~

8

20

8

4

2

50_ ___ _ _

100 14

200 8

1 Samples are 4.0 by 0.5 feet taken across the bed. Bold figures represent total numbers of samples suggested as

being feasible to take per bed of 500-foot length and still retain fairly good accuracy.

2 Approximate only, with plants averaging about 90 per 4.0- by 0.5-foot counting plot, or 45 per square foot.

TABLE 34.—Number of counting plots required in inventory of nursery transplants which will be within

specified limits of error ^

Total

length

of bed

Total

number

of trees

expected ^

Samples required per bed when specified percent of error

Number of

beds In uniform bed is— In nonuniform bed is—

0.25 0.5 1 2 3 5 0.25 0.5 1 2 3 5 10

1 ___

Ft.

500

1,000

2,500

5,000

10, 000

25, 000

50, 000

100, 000

Thousands

18

36

90

180

360

900

1,800

3, 600

No. No. No.

18

9

4

1

1

No.

4

2

1

No.

2

1

No.

1

No. No. No. No.

47

24

9

5

2

1

1

No.

21

10

4

2

1

No.

8

4

2

1

No,

2

2 1

5

6

3

2

14

7

4

1

1

I

36

19

9

4

2

1

1

10

20

50 15

8

4

100

200 15

1 Samples are 6-foot-long sections of individual rows. Bold figures represent total numbers of samples suggested

as being feasible to take per bed of 500-foot length and still retain fairly good accuracy.

2 Approximate only, with trees averaging about 31 per 6-foot counting plot, or about 9 per square foot of bed.

Forest Nursery Practice in the Lahe States 99
departure from strictly random sampling, but

since pace length is likely to vary somewhat the

net pattern of sample distribution would be as

good as a random scatter.

Some nurserymen rely solely on bed inventory

estimates for the larger orders of stock, totaling

around 100 thousand trees or more. Should an

estimate, accurate within 3 percent, be desired on

such an order, some 46 sampling units would be

required, provided the seedbeds are uniform. For

small shipments of only a few thousand trees, a

100-percent count of the trees must be made after

digging.

It will be noted that table 33 assumes that at

least 1 sample is taken in each 500-foot-long bed.

The table will probably serve nurserymen most

usefully by giving them an idea of how small a

sample is required for larger lots of stock, that is,

those involving 1.8 million trees or more. For

such lots as few as 1 or 2 samples per bed will

usually give an accuracy of within 3 percent in

uniform beds; about 3 sampling units are needed

to be within 5 percent accuracy in nonuniform

beds.

In the above examples, the uniform beds were

1-0 red pine sown to get about 50 trees per square

foot and which actually averaged 45.0 per square

foot. The nonuniform beds were 2-0 red pine

which were sown to get about 50 trees per square

foot but, due to unusual losses from wind and

heavy rain which flooded the beds, they averaged

only 16.5 trees per square foot.

Table 34 is based on 6-foot-long sampling units

from individual rows. The trees were planted

mechanically with a Holland transplanter in 7

rows per 4-foot-wide bed, with the rows running

lengthwise of the bed. The uniform beds averaged 30.6 surviving plants per 6-foot counting

plot; the less uniform beds averaged 28.7 surviving

trees.

Table 34 shows the number of such sampling

units to take at random in the nursery inventory

of transplants. If a nurseryman had 50 beds,

each 500 feet long, all of them containing about

900 thousand trees, the average stand computed

on the basis of 1 sample 6-foot-row count taken at

random in each of the 50 beds would, on the basis

of the sample study made here, give an overall

estimate of within 0.5 percent. In the nonuniform beds, it would require 15 samples per bed to

obtain the same accuracy, or 4 samples per bed to

obtain a 1.0 percent standard error for the entire

lot of 50 beds.

It should be kept in mind that each individual

seeding must be sampled, such as a seed source,

age of stock, species, year of collection of seed,

and season of sowing or transplanting if these are

causes of variation in the average stand per square

foot, as is likely to be the case.

For instance, if a nurseryman had 50 beds of

nonuniform 1-0 white spruce and 20 beds of uniform 2-0 red pine and wanted an estimate on each

lot within 2 percent, he would need to make 8

counts in each bed of the white spruce or a total

of 400, and 5 counts in each bed of red pine or a

total of 100 counts (table 33). The total in any

one lot of trees is then calculated by multiplying

the total square footage of seedlings by the average

stand per square foot as derived from the average

of all frames.

For transplants, the total linear footage of

individual rows is sometimes used as the basis for

calculation. If square feet of net bed area is used

for transplants, figuring a bed as 4 by 500 feet,

or 2,000 square feet, each individual 6-foot-long

counting row accounts for 3.43 square feet of bed.

The net plantable number of trees is calculated

by reducing the total by the cull percent, which

is usually made by the nurseryman himself from

experience as tempered by actual dug samples.

Usually, 10 to 20 samples are the maximum that

would be taken in any one lot of stock for estimate

of cull percent. In larger transplants, such as

2-2, the cull percent should be so low that no dug

samples are necessary for cull estimate.

For inventory of large or uniform lots where

less accurate estimates are needed than those obtained by taking one sampling unit per bed, the

percent of error when taking the single sample in

every other bed can be estimated by doubling the

percent of error given in tables 33 and 34. If

every third bed is sampled with one counting plot,

the percent of error in the tables should be multiplied by about 2.5. If only every fourth bed is

sampled by one counting plot, the percent of error

will then be about three times that shown in the

tables.

100 Agriculture Handbook 110^ Ü, S. Department of Agriculture
LIFTING, GRADING, AND PACKING OF NURSERY STOCK

When nursery stock is ready to be outplanted

or sold, it represents all of the costs, direct and

indirect, that have accrued over a period of years

in producing it. It is important, therefore, that

the digging, pulling, and packing of the trees be

supervised closely so that the investment can be

liquidated fuUy.^^

Nurseries making shipments of many small lots

of 1,000 to 5,000 trees involving a number of

species have a complex tree-distribution problem

compared to those that distribute larger lots and

handle only a few species and classes of stock. In

U. S. Forest Service nurseries of the Lake States,

stock is produced exclusively for planting on national-forest lands. Consequently, there is no

need for making an accurate count of the trees or

to put the stock up in small bundles. Usually,

the inventory by individual seedbeds is a good

basis for estimating how many linear feet of bed

must be dug for specific orders of trees.

State or private nurseries, which must provide

an accurate count of the trees for the many small

orders filled, invariably put trees in tied bunches

of 20, 25, 50, or 100 at the time of packing.

DIGGING

For a small nursery, stock can be dug for shipment fairly cheaply with a spade or a fork. For

large nurseries, however, mechanical devices for

digging stock are indispensable. Besides greatly

reducing the digging costs, a better job of loosening

the soil to facilitate pulling the stock can be

accomplished with a tree digger than by hand

methods (see page 37 for description of tree lifters

and page 79 for details of lifting stock).

An agitator-type mechanical lifter was devised

in 1952 by R. O. Sowash while superintendent of

the Eveleth Nursery in Minnesota. It differs

from the standard lifter in that a crankshaft with

eccentrics is mounted below the tines or shakers.

The crankshaft is run at about 900 rotations per

minute from a 2-hp. gasoline engine mounted

forward on the tree lifter. The agitating effect of

the eccentrics on the shakers has a loosening effect

on the soil, leaves the roots standing upright in the

loose soil with none of them exposed, and permits

more rapid pulling of the trees without root injury.

20 Stock of some species grown in the southern part of

the Lake States region may suffer injury or death if the

roots are exposed to freezing during handling, shipment,

or storage. The species most susceptible to such injury

probably is black locust.

Forest Nursery Practice in the Lake States

The lifter itself was pulled by a 40-hp. caterpillartype tractor.

In New York and Pennsylvania State-nurseries,

2-row potato diggers are used to lift and shake soil

from small trees, according to E. J. Eliason of the

New York State Department of Conservation.

These diggers are wide enough to lift a 4-foot bed,

or an equivalent width of transplant rows.

PULLING

It is important that the pulling crew be thoroughly trained so as to insure a minimum of

injury to the seedlings. A description of their

work is given in the section Lifting Stock for

Transplanting, p. 79.

The practices used in caring for the stock as it

is removed from the beds vary with the class of

stock, the amount of culling required, and how and

where the stock is packed for shipment. In larger

Lake States nurseries, the plants are gathered in

small boxes and taken to a central point where

they are packed in crates or bundles for shipment.

Each puller fills his own box. (Boxes are 26

inches long, 17% inches wide, and 8% inches deep.)

As the trees are pulled and sorted they are placed

in the box in layers between pieces of moist burlap

to protect them from drying out.

If the percentage of call trees is negligible, the

culling can usually be done in the field at the time

the trees are pulled. The trees are spread out

loosely in the shade of the puller's body and

rapidly examined for undersized, mechanically

injured, and diseased plants. These are discarded

and the acceptable plants placed in pickup boxes

(fig. 54).

Where the percentage of cull plants is relatively

high, or the trees must be counted and tied in

small bunches, it ordinarily is more satisfactory

to do the culling and tying in a building equipped

for this purpose. Culling tables of various types

have been tried in U. S. Forest Service nurseries

with varying degrees of success.

Some nurserymen have found culling tables

equipped with endless belts very effective (fig. b^),

especially where an accurate count of the plants

is necessary {172). When used as a device for

counting trees, the belt is divided into a given

number of units or spaces—usually 50—and the

spaces numbered from 1 to 5, depending upon the

number of workers assigned to placing trees on

the belt. As the belt travels along, a certain

number of plants—usually 2—are placed in each

101
~' ^1 II 1 '

^'lÊm r 1

1

■■ '-^«ip ii

FIGURE 54.—Pulling red pine seedling stock for transplanting. Each puller culls and packs his own box of

trees. (Chittenden Nursery, Wellston, Mich.)

F-473S37

FicuEE 65.—Culling or grading table with endless belt.

space. Thus, an accurate count of 100 trees

is obtained.

Where culling and counting is done under

shelter, the trees should be kept moist with wet

burlap or other media during sorting. Undue

exposure of the roots impairs the vitality of the

plant and reduces its chances of surviving when

planted in the field.

GRADING

In any lot of nursery stock there usually are

some trees not suitable for field planting or nursery

transplanting because they have been damaged

or are too small (149). Such stock is sorted out

and discarded. In seedling stock, the bulk of the

discards is likely to be very small plants of low

vigor (fig. 56). The percent discarded may range

from 5 to 20 percent, and occasionally more. In

102

FiGTRE 56.—Samples of 3 grades of 2-0 red pine stock

designated as large, medium, and small, used in field

survival test of graded stock. At end of 2 drought

years in the field, the average field survivals of the 3

classes of stock were 44.1, 36.5, and 29.1, respectively.

Least significant mean diff'erences between these 3 values

are 7.6 at 5-percent level, and 11.0 at 1-percent level,

indicating definite advantage for larger stock. (Background is 1-inch squares.)

transplants, the percent of discards or culls should

seldom be more than 1 to 3 percent. In fact, no

culling need be done with transplants except for

an occasional tree that is root-stripped or split.

Tables 35 and 36, which are based on general

experience in the Lake States and supplemented

by a number of nursery and field experiments,

provide a guide for grading nursery stock. Caliper

is the chief criterion because it reflects relative

size and, usually, sturdiness. The goal should be

production of premium grades of stock. Premium

grades are those that are well balanced and

exceed the indicated seedling or first-year transplant caliper specifications by %^ inch or more

and the second-year transplant specifications

by %4 inch or more.

Culling out of undersized trees is done by

ocular estimate of minimum specification. Barton

(5) devised a simple training aid for workers for

grading trees. It consists of a welding rod 13

inches long and }i inch thick, with two 2-inch-long

pieces welded at right angles across the top at 4

inches (or minimum top length) from the top end.

The intervening }á-inch space between the cross

rods acts as a caliper gage. Acceptability of top

length is judged by whether the seedling has a

4-inch-long top. Another 2-inch-long crosspiece

is welded 1 inch above the bottom of the long rod

to give an 8-inch interval between the 2 sets of

horizontal 2-inch-long crosspieces. The 8-inch

length is for checking acceptable root length of

field planting stock.

Balance is based on the ratio of weight of top

to weight of root (146)- For Lake States conifers,

top-root ratios, on a green weight basis, of less

than 3:1 are considered very good; those around

Agriculture Handbook 110, Ü. S. Department of Agriculture
TABLE 35.—Minimum specifications jor stock jov

nursery transplanting ^

Species and age

class (years)

Period

to be

left in

nursery

as transplants

Minimum

caliper

at

ground

level

Minimum

top

length

to tip of

terminal

bud

Estimated

usual

cull of

seedling

stock

Jack pine:

Years

1

1

2

2

1

2

1

2

1

2

1

2

}Í4. inch

4

4

3

2

4

3

3

2

4

3

4

4

Inches

1.5

2.0

1.5

1.0

2. 0

1,5

1. 5

1.0

2.0

1. 5

2. 5

2.5

Percent

15

Red pine:

2-0 15

2-0 10

1-0 15

White pine:

2-0 10

2-0

1-0

1-0

5

5

2

White spruce:

2-0

2-0

20

15

3-0

3-0___

10

10

1 Minimum root length permissible is 3 inches if well

branched, or 4 inches for the usual run of stock.

4:1 are fairly good; at 5:1 the trees are considered

rather topheavy, and at 6:1 very topheavy {160),

The last two groups are likely to suffer severe

losses from drought, heat, and competition with

other plants, or from overwinter losses in fall

plantings. Good balance is largely attained in

Lake States nurseries by use of transplant stock,

by avoiding leaving the seedlings too long in the

seedbed, and by using low densities in the seedbeds.

Not much information is available as a guide

for grading hardwoods. Generally, broadleaf

species should have a minimum stem caliper of

%4 inch at the ground line to give good field

survival for 2-0 stock and ^%^ inch for 3-0 stock

(table 37). At reasonable densities of about 10

plants per square foot of bed, or per linear foot

of drill (spaced at least 9 inches apart), the cull

percent in discarded stock should not be over 15 or

20 percent, and often may not be over 10 percent.

TABLE 36.—Minimum specifications jor stock Jor

field planting ^

Species and age class

(years)

Minimum

caliper at

ground

level

Minimum

top length

to tip of

terminal

bud

Estimated

usual

cull

Jack pine:

l-0__

}^4 inch

5

5

6

5

5

6

5

6

8

5

6

5

6

6

6

6

6

6

5

6

6

6

Inches

2. 50

2.75

2.50

3.00

2.50

3.00

2.25

2.75

4.00

2.25

4.00

2.25

2.50

2. 50

3.00

3.00

3.00

3.00

3.50

2. 75

3.50

3.00

3.50

Percent

30

l>^-0 20

1-1 3

2-0 15

Red pine:

2-0 20

3-0 ___ _ 15

2-1 5

1-2 2

2-2 2

White pine:

2-0_ ___ ___ 20

3-0 10

1-1 __ __ 10

2-1 5

1-2 __ _ 2

2-2 2

White spruce:

3-0 30

2-1

3-1

2-2

15

10

2

Black spruce:

2-0 20

3-0

2-1

2-2

10

10

2

1 Minimum root length is 5 inches for well-branched,

fibrous root system; for the usual run of stock, 6 inches or

more of root length is satisfactory.

PRUNING

The mechanical devices customarily used for

digging trees can be adjusted to sever the taproot

at the proper point, but they do not cut the shallower lateral roots. Since many of the lateral

roots exceed the length required for field planting

stock, it usually is necessary to do a small amount

of root pruning. This operation ordinarily is performed at the time the trees are being packed for

shipment.

TABLE 37.—Field survival and growth of planted hardwood species as afected by nursery grades based on size

Species and nursery grade

3-0 yellow birch:

Large

Medium

Small

3-0 paper birch:

Large

Medium

Small

Top

length

Inches

34.3

19. 9

12. 5

43.9

30. 6

15.7

Root

length

Inches

11.2

9.7

6.7

Fresh

weight

per tree

Grams

47.8

9.5

2.4

59. 9

19.3

2. 6

Stem

diameter

at ground

line

)^4 inch

26

15

8

26

19

9

First-year field survival

Good

vigor

Percent

92

94

70

98

94

70

Poor

vigor

Percent

6

6

18

1

6

18

Total

Percent

98

100

88

99

100

88

First-year

height in

field

Feet

2.0

1. 1

.5

2.8

2. 2

1. 3

Forest Nursery Practice in the Lake States 103
For pruning roots of excessive length, a number

of tools and devices have been tried, including

large paper trimmers, shears, and rotary pruners

run by electric motor. A cleaver, used with a

hardwood block, has proved to be an effective tool

for root pruning conifers (101). The device has a

straight blade made of K-inch-thick sheet steel

with dimensions of 12 by 6 inches. Its cutting

edge is straight. The sheet is fitted into a handle

18 inches long and fastened with 3 machine bolts

Yi hj 1% inches with a %-inch head.

The plants are assembled in small bunches,

placed on the wooden block, and the roots cut

with a downward stroke of the cleaver. To insure a uniform job, experienced workers should

be assigned to this work. Seedlings with roots

pruned too short are apt to succumb to drought

conditions when planted, and if the roots are too

long the seedlings are difficult to plant properly.

Under most conditions in the Lake States, a root

length of 8 inches is satisfactory.

PACKING

Since the manner in which the plants are packed

for shipment influences the length of time they

can safely be kept in storage and the condition

of the trees when received at the planting site,

the packing should be done by experienced and

thoroughly reliable workers.

Packing can be done more economically in the

nursery. Therefore, it is standard practice at

U. S. Forest Service nurseries in the Lake States to

pack in the field. One or more portable packing

shelters, convenient to water and transportation

facilities, are placed on the area from which the

stock is to be dug. Each shelter is provided with

at least one large barrel for soaking the packing

medium. The shelter is large enough to accommodate two tree balers or an equal number of

crates, and a supply of pickup boxes as they are

brouglit in from the field filled with trees. An

8- by 10-foot unit, with a 7-foot back wall and a

9-foot front wall, constructed of 2- by 4-inch material, well braced, makes a satisfactory shelter

(fig. 57). Canvas is used to cover the top and

enclose two sides to protect the trees from drying

out during packing.

State nurseries that pack relatively large numbers of small orders usually find it advantageous

to do their packing indoors, using a well-spaced

layout of tables on which the trees can be paclted

and tagged for shipment in orderly fashion. A 1-

or 2-days' supply of recently dug trees of various

species and age classes, or a reserve in cold storage enables them to fill orders during inclement

weather.

The type of container in which the trees are

packed depends to some extent upon the species of

stock, size of the shipment, method of transportation, and distance the trees are to be transported.

Conifers are packed in either bundles or crates, but

hardwoods usually are packed in bundles. For

shipment to nearby areas on the national forests,

crates often are used (fig. 58). For long-distance

shipping either by truck or rail, where excess

weight or the extra cost of returning crates to the

nursery is a factor, the stock is packed in bundles

or bales. The weight of bundles is negligible

compared to the 30-pound weight of crates.

Either method requires about the same amount of

sphagnum moss or shingle tow (shavings from

shingle manufacture) for packing.

The State nurseries in the region prefer to

bundle the trees in asphalt-impregnated paper or

burlap-backed paper and tie them with stout cord.

FIGURE 57.^A, Packing shelter. Two men pack and bale the seedlings. Bales of packed seedlings are ready to be

hauled to the cold storage plant until needed in the field. B, Closeup of baler and tying machine. Notice iron bar

used to twist slat and to draw burlap tight around bundle. (Chittenden Nursery, Wellston, Mich.)

104 Agriculture Ilandhooh 110, U. S. Department of Agriculture
30"

TOP IN PLACE SHOWING USE OF r'xl|x20*

KEY FOR LOCKING COVER ^^^^

,11 -, II I X 3 NAI L^

-^x3"

^x3"

I" -,.. -¿- X 3

III -, II I X 3

TZLä- msa:

20"

o

CVJ

TO

x3"

x3"

yx 3

ix3"

X 3

SIDE

FIGURE 58.—Details of

shipping crate construction.

END

-J5

T

"HCM

im/À

I x3 >L

. 1 Í -\ I 11\

ii"x3'i;

'^8

yx3' -2X3

I" I YX3'

, il x3 11

II II II 4J—

-^lV3^'

:^ ~v//7X

TOP SHOWING COVER

FRAME MEMBERS T'xS"

ROUGH LUMBER

ALL OTHER MEMBERS

-i^'x3"R0UGH

3x8 GAL. IRON

STRAPS AT 4.

TOP CORNERS

SUPPLY l"x 1^ X 20"

KEY FOR EACH COVER

Data from one Lake States nursery show that

about 100 bales, each of 60 pounds, or a total of

600,000 pine trees, can be loaded on a truck {91).

When crates are used, they are usually Uned with

burlap. (Some nurseries prefer a lettuce crate

with a paper liner, said to be somewhat less subject

to molding.) The burlap prevents the loss of

packing material while the stock is in transit. It

should be of a size to cover the bottom of the

crate, the two sides, and lap over the top. A

layer of moist packing material is placed on the

burlap in the bottom of the crate, then a layer of

trees, with the roots to the center and slightly

overlapping. Alternate layers of trees and packing material are built up until the crate is full.

While the crate is being filled, packing material

is wedged between the roots and the sides of the

crate. A mosser will facilitate this work (fig. 59).

Two mossers are inserted, one on each side of the

crate, and mossis pushed down into each in a layer.

After the crate has been filled with alternate layers

of trees and moss, the mossers are pulled out,

leaving a uniform layer of moss on two sides of the

Forest Nursery Practice in the Lake States

crate. The trees should be packed tightly with

the top layer extending above the top of the crate.

When the crate is full, the loose ends of the burlap

are brought together over the top layer of moss or

shingle tow and the lid of the crate forced into

place.

Four layers of moss, including the bottom and

top and two equally spaced intermediate layers of

packing material, have proved adequate for the

average size crate. Each layer should be 2 to 3

inches thick and thoroughly moist when placed

in the crate. Moist material about the needles

reduces aeration and transpiration and impairs

the keeping quality of the trees while in the

container.

In preparing a bundle or bale of trees, 2 pieces of

13-gage, galvanized tie wire 66 inches long are first

placed in proper position in the tree baler (fig. 60)

with the ends of the wires bent down over the front

and back. Two 1- by 2- by 24-inch wooden strips

are then placed in position on top of the wires. A

20- by 60-inch piece of burlap is placed over the

wires and wooden strips with the ends drooped

105
FiGUEE 59.—A metal crate

mosser that facilitates

placing an even layer of

moss about 1}^ inches

thick between sides of

the crate and the trees.

FIGURE 60.—Tree baler. 3^

-ICM

Front Side

=4- 1 II " " II 1

f^k -

'U

-fevj r- -1

^^^==^^

Top r

-n^ "-^

106

Hinge detail

Agriculture Handbook 110^ Ü. S, Department of Agriculture
over the front and back. A layer of wet packing

material is then spread out on the burlap followed

by a layer of trees in a double tier, with roots to the

center and slightly overlapping. Alternate layers

of packing material and trees are added imtil the

baler is full. Special care is necessary to work

packing material between the roots of the trees

and the burlap to insure a complete aad unbroken

layer about the trees when the packing is finished

and the bale is bound together.

When the baler is full, the 2 ends of the burlap

are brought together and wrapped around a third

1- by 2- by 24-inch wooden strip. A special tool

or wrench is placed on one end of the strip and the

strip is twisted and the burlap drawn up tightly.

After the burlap is tight, the operator holds the

tension on the wrench by throwing his leg over the

handle or secures it by holding it with a lock

attached to the frame of the baler. The loose

ends of one wire are then brought together and

inserted into the proper notches of the tying

machine and drawn tight by turning the handle

on the machine. The second wire is handled in

the same manner, and the bale is completed.

Wales {18J^) states that the cost per M for

packing trees was 18 cents when using the Olson

baler along with the Girard wire-tying machine

as compared to 27.7 cents when using regulation

crates. In some nurseries, %-inch steel strapping

has supplanted wire ties.

Crates or bales of trees should not be stacked

closely or left unprotected in the field for prolonged periods. Stock that is to be held several

days at the nursery should be placed in cold

storage at 34° to 40° F.

In the Lake States, several kinds of material

are used for packing. Sphagnum moss and shingle

tow have been used extensively with equally good

results. Although sphagnum moss has greater

moisture-holding capacity than shingle tow, it

tends to cause heating in the bales or crates more

readily than shingle tow unless it is precured.

The green moss also compacts tightly and reduces

aeration within the container. Where moss is

gathered locally, it should be collected early

enough so that it can cure 3 or 4 months.

The moisture-holding capacity of shingle tow is

greatly increased after the wood fibers are broken

down. Consequently, old material is better than

new or freshly cut material. Storing it out of

doors will hasten deterioration. Because shingle

tow absorbs moisture slowly, it should be soaked

in water for a considerable time prior to its use.

A mixture of sphagnum moss and shingle tow

of equal proportions has good moisture-holding

capacity and provides adequate aeration for stock

packed either in crates or bales. Some nurserymen have also used partially decomposed peat

very effectively as a packing material. Peat usually is lumpy when dug from the bog and its

physical condition can be greatly improved if it

is put through a shredder.

SHIPPING WEIGHT OF TREES

The shipping weight of nursery stock varies

according to species, age classes, and methods of

packing (table 38). Younger classes of stock also

occupy less space per thousand trees. For example, when packed in bales, 6,000 2-0 red pines

have about the same volume as 3,000 3-0 trees or

2,000 2-2 trees. Stock packed in bales usually

weighs about 13 to 30 pounds less per thousand

trees than that packed in crates:

Jack pine Red pine White pine

Bale- (^-^> (^-^) ^^"^^

Trees number__ 2,325 1,551 734

Weight per bale.__pounds-- 83 87 113

Weight per M trees, pounds. _ 36 56 154

Crate:

Trees number__ 2,816 1,781 991

Weight per crate, .pounds__ 156 153 166

Weight per M trees,pounds.. 55 86 167

TABLE 38.—Approximate shipping weight per

thousand trees of nursery-grown forest planting

stock packed in shingle tow and sphagnum moss

and wrapped in heavy paper ^

Species

Fir, balsam

Do

Pine, jack

Pine, red (Norway) _

Do

Do

Pine, white

Do

Do

Redcedar, eastern. _

Do

Spruce, Norway

Do

Spruce, white

Do

Ash, white

Do

Locust, black

Oak, red

Walnut, black -.

Packaged

weight

per

thousand

trees

Pounds

50

70

50

50

75

100

40

60

90

65

90

60

80

50

70

50

70

50

50

60

1 Information supplied by Wisconsin Conservation

Department.

Forest Nursery Practice in the Lake States 107
STORAGE AND SHIPMENT OF NURSERY STOCK

Scheduling of operations at the nursery to

make the best use of available labor often is

difficult. The problem is likely to be most acute

at the time stock is being lifted and new beds

sown. Unexpected delays also may be encountered after stock has been delivered to a planting

area. Therefore, means of storing stock without

deterioration are necessary.

Broadleaf species can be dug in the fall, counted,

and heeled-in in trenches until spring without

suffering ill effects. Conifers, however, cannot

be heeled-in over winter without severe loss.

Hence, the lifting of conifers must be delayed until

spring, and if stock is to be held for some time

before transplanting or shipment it must be

placed in cold storage. For limited storage of

several days to a week in the spring, conifer stock

can be heeled-in in a cool shaded area. The soil

must be moist and thin layers of stock must be

used. Cold storage or a cool cellar are preferred

even for this limited period. Cold storage is

also a means of providing a reserve supply of

stock for keeping nursery labor busy at such tasks

as grading or packing during periods of inclement

weather.

Preferred storage temperatures in the range of

34° to 40° F. can be maintained with mechanical

refrigeration or the use of ice. When a refrigeration unit is used, it must be so planned that it will

operate well when several hundred thousand or

more trees are in storage. If ice is used, the

stock is placed in layers on shelves or racks with

the tops of the seedlings to the outside and the

roots slightly overlapped to the inside where

they are packed in iced moss or shingle tow.

Chunks of ice are then placed on top of the packing

medium.

Since the temperature inside tightly packed

bundles or crates of trees may be 10 to 20 degrees

warmer than that of the chamber at the beginning of storage, molding and rotting of roots or

tops may occur unless certain precautions are

FIGURE 61.—Comparison of first-year

nursery survival of four species of

conifer stock in a cold storage experiment. (Hugo Sauer Nursery, Rhinelander, Wis.)

^ No storage. Stock lifted and transplanted the same day.

•;-j:;| storage at 50° F. Figures in bar represent weeks in storage before planting.

108 Agriculture Handhooh 110, Z7. S, Department of Agriculture
taken in packing. The stock should be packed

in the shade, and cold packing materials and cold

water used. Cakes of ice dropped into the barrels

containing sphagnum moss and water will lower

the temperature satisfactorily. Stock in storage

is watered once a week. Watering is facilitated

by a small metal tube, attached to a hose, which

is thrust halfway into the bales or crates to get

water to the moss and roots.

An experiment on effect of storage on survival

and growth of coniferous nursery stock was run

in 1938 at Hugo Sauer Nursery at Rhinelander,

Wis. Representative lots of 1-0 jack pine, 3-0

red pine, 3-0 white, pine, and 2-2 white spruce

were lifted on May 3 and stored in accordance

with usual practice at that time. The stock was

packed in crates and placed in a refrigerated room.

Air temperatures before May 15 were generally

at or below 50° F., with an absolute minimum of

38°. After May 15 they occasionally reached 60°

to 65° for periods of several hours because of more

frequent use of the cold storage facilities and larger

amount of stock in refrigeration, which therefore

threw a heavier load on the refrigeration unit.

Temperatures in the root zone, of course, fluctuated much less than the air temperature.

Trees were taken from the stored lots and

transplanted at weekly intervals beginning May

10 and ending June 7. Similar lots were lifted

from the nursery beds and transplanted at the

same dates for comparison.

First-year survivals indicated very little difference between stored or unstored stock of 3 pine

species in a 5-week period (fig. 61). WTiite

spruce, however, showed a considerable drop in

survival for stock held in storage for 5 weeks.

The lot lifted in the nursery and planted on the

same day (June 7) gave 100-percent survival.

The results for 5 weeks' storage were significantly

poorer in an analysis of variance than for shorter

storage periods. The results of this test provide

some guide as to the safe maximum period of

storage under conditions of limited temperature

control.

Nursery survival alone is not a complete

criterion of the effect of prolonged storage; one

of the most serious effects is the loss of growth of

the trees. Nursery stock stored for 5 weeks was

distinctly smaller at the end of the first season

after transplanting than the stock stored for

shorter periods. Comparing the size of stock

at the end of the first season in the nursery, the

reduction in weight of stored versus unstored

trees was 42 percent for the jack pine, 28 percent

for white spruce, and 20 percent each for red and

white pines (fig. 62). The difference is attributed

mostly to the fact that the unstored stock had

a 5-week longer growing period, largely in May,

which is one of the most favorable months.

Stock lifted directly from the seedbeds and

transplanted the same day survived very well

for all plantings made from May 3 to June 7, but

the early season transplantings produced somewhat larger stock of better color than the later

transplantings. For example, the stock lifted

and transplanted on June 7 was lower in weight

than that transplanted on May 3 by 35, 18, 8, and

3 percent respectively for jack pine, red pine, white

pine, and white spruce. Color difference in

foliage was especially striking in case of white

spruce; here the percent of stock with light

yellow-green foliage (perhaps indicating a nitrogen

deficiency) in September 1938 was 12.3, 16.0,

33.0, 44.3, 52.3, and 71.7 percent, respectively,

for unstored stock transplanted May 3, 10, 17,

24, 31, and June 7, respectively. Such yellowing

can, of course, be offset to some extent with

liquid fertilizers.

In a second series of the experiment started 2

weeks earlier, representative lots of jack pine,

r-372138, 372136

FIGURE 62.—A, Decrease in size of 3-1 red pine from late

transplanting. From left to rigiit, trees were lifted and

transplanted on the same date at weelcly intervals on

May 3, 10, 17, 24, 31, and June 7. B, Decrease in size

from prolonged storage and progressively late transplanting of 1-1 jack pine. From left to right, trees

were transplanted on May 3, 10, 17, 24, 31, and June

7, and had respectively 0, 1, 2, 3, 4, and 5 weeks in

storage prior to transplanting. All trees were lifted on

May 3. (Hugo Sauer Nursery, • Rhinelander, Wis.

Background is 1-inch squares.)

Forest Nursery Practice in the Lake States

408189°—57 8

109
red pine, white pine, and white spruce were dug

at 1-week intervals beginning April 19 and ending

May 24, thus giving a range of storage intervals

of 0, 1, 2, 3, 4, and 5 weeks. All trees were field

planted on May 25. Survival counts made at

the end of the first year indicated that survivals

were generally quite satisfactory even with 5

weeks of storage (fig. 63). However, 1 lot

stored for a 4-week period showed a significant

10-percent reduction in survival for jack pine,

red pine, and white spruce. The only explanation

for the poorer survival is that the trees were

just breaking dormancy on the date of lifting

(April 26) and may have been particularly

sensitive at that stage.

Based on these tests and experience in regular

nursery operations, storage can be recommended

for conifer nursery stock for periods as long as 5

weeks. The loss in size of stock caused by prolonged storage is most serious for 2-0 red and white

^^^^ -^-

"^<^^^-y

L=J ======^^«ÄU:==:^ L

0 1 2 3 4 5

WEEKS IN STORAGE

MAY 24 MAY 17 MAY 10 MAY 3 APRIL 26 APRIL 19

DATE LIFTED FOR STORAGE

FIGURE 63.—Effect of storage on first-year field survival

of stock of 4 species.

pines scheduled for field planting as 2-1 stock.

Such stock, stored for as long as 4 to 6 weeks

before transplanting, is really only 2K years old

as far as growth or development is concerned

when it is lifted for field planting. To get full

development, it should be transplanted early.

Long storage of seedlings is less harmful if the

stock is scheduled for two seasons in the transplant bed, because second-year transplants usually

make good growth and are invariably large enough

to give excellent survival in the field.

When shipped, nursery stock should be in transit

as short a time as possible to avoid heating, molding, or drying out of the trees. On public and

industrial forests, larger quantities of planting

stock usually are transported in l^-ton trucks or

larger units such as truck trailers. A l^-ton

truck can haul about 60 thousand 2-2, 90 thousand 3-0, or 180 thousand 2-0 trees if crated, and

about 50 percent more of each class of stock if

packed in bales. On occasion, about 500 thousand of rather small 2-0 red pine or 1-0 jack pine

have been successfully hauled in 1 trip on a 1 K-ton

truck. Pickup trucks or jeeps are frequently

used in short hauls of smaller quantities of stock,

especially where these may be going directly from

the nursery to nearby planting crews.

State nurseries usually rely on railway express

shipments or motor freight for serving customers.

For the usual nonrefrigerated shipment by

truck, the chief precaution is to check the line of

travel for existing temporary load limits that

may have been imposed during or following spring

breakup. The cargo should be well protected

against the sun and wind with tarpaulins. In

warm weather, it may be possible to do most of

the trucking in the cool of the night. Watering

enroute should not be necessary with loads of

trees properly packed and protected against wind

and sun. On arrival at the destination, the stock

should be unloaded immediately in a building,

under shade of trees, or in a field ice-house constructed for stock storage. Ideally, not more

than 3 to 7 days should elapse from the time trees

leave the nursery or cold storage plant until they

are field planted.

110 Agriculture Handbook 110^ TJ, S, Department of Agriculture
COST OF TREE PRODUCTION

The cost of growing stock will vary between

nurseries depending upon their size, the methods

and practices used, the number of species and age

classes produced, seed costs, wages paid to laborers, and specifications set for acceptable planting

stock. Losses resulting from insect attacks, diseases, unfavorable climatic conditions, or other

causes, raise the cost of producing stock by reducing the output of plantable trees.

Cost keeping, besides being a means of determining the actual cost of production, frequently

reveals which costs are out of line. Thus, by

analyzing the cost of each operation, the nurseryman can initiate changes to improve the efficiency

of the work and effect savings in production costs.

This is particularly important in operations that

involve handling large amounts of stock, such as

transplanting and distribution. Although the

cost of stock is important, quality of the trees

should not be sacrificed. The objective should be

to raise adequate planting stock at minimum cost.

U. S. Forest Service nurseries classify all

nursery expenditures into 11 projects. The costs

are kept currently, by major and minor projects,

and at the close of each fiscal year are brought

together into five major projects. Cost per thousand trees in each project is then determined.

Nursery expenditures are currently charged to

one of the following projects: Major Projects.

(1) First-year seedlings; (2) second-year seedlings;

(3) first-year transplants; (4) second-year transplants; (5) tree distribution. Minor Projects.

(6) Maintenance of soil fertility; (7) mess; (8)

work animals and motor vehicles; (9) administration; (10) general maintenance; (11) investments

other than planting stock (permanent improvements and equipment).

In practice, the cost for labor, materials and

supplies, and equipment used is charged direct to

the project on which the labor is performed and

the materials and supplies used. For example,

rotary tilling the soil in preparing seedbeds, sowing

seed, mulching seedbeds, removing mulch, watering, weeding, and all other items of cost during

the first year, except the value of the seed, are

chargeable to Project 1, first-year seedlings. The

cost of seed is brought into the cost of tree production as a separate entry on the cumulative record

for the lot of stock to which it is chargeable.

Expenditures directly chargeable to other projects are similarly charged to the projects involved,

including the nurseryman's time.

When the cost-keeping records for the major

projects are closed, the charges for the various

minor projects are added. This is done by prorating the minor charges among the major projects on the basis of time in hours spent on each

major project, or on the basis of hours of use or

miles operated in the case of work animals,

tractors, and motor vehicles.

Ordinarily, costs of fertilizing are charged currently to the major projects affected. However,

extraordinary expense, such as stockpiling a

quantity of peat or preparing compost for future

use, is deferred and charged off as the material is

used. Where maintenance-of-soil-fertility charges

do not vary materially from one year to another,

it is taken into account currently in determining

tree production costs; otherwise it is charged off

once in every 2- or 3-year period.

The cumulative or final cost of the stock, as

determined by U. S. Forest Service methods of

cost accounting, includes the average cost per

thousand for each major project during the period

the stock is in the nursery. For example, a block

of red pine produced and shipped as 2-1 transplants includes first the cost of the seed, to which

is added the average cost per thousand for firstyear seedlings. Then, at the end of the second

year, the cost for second-year seedlings and the

average cost per thousand for transplanting (if

transplanting is done in the fall) is added. The

third year the stock is charged with project costs

for care of first-year transplants and, finally, with

stock distribution project costs and depreciation

set up for 3-year stock.

It has been found that a further breakdown in

costs by species shows relatively little difference in

the unit cost per thousand. A slight difference of a

few cents per thousand normally may be expected

if some species are grown more densely than others

or require shading during the first year. However,

the efforts and expense involved in keeping labor

and material and supply costs for each species or

block of stock to determine the difference can

hardly be justified.

Typical costs of growing nursery stock in a large

Federal nursery in each of 4 one-year periods, from

first-year seedlings to four-year transplants, are

relatively high for the first year in the seedbed and

the first year as transplants, and less for the other

2 years. The cost in 1948, including depreciation

and distribution, is shown in the following

tabulation :

Production Cumulated

cost per depreciation

thousand per thousand i

First-year seedlings $1. 85 $0. 17

Second-year seedlings .45 .33

First-year transplants 5. 48 .50

Second-year transplants 1.81 .67

Distribution (lifting and packing) _ 1. 27

1 Based on 20 million production and $10,000 total

annual depreciation.

The cost per thousand trees packed for shipment

would be as follows: 2-0 stock, $3.90; 2-1, $9.55;

and 2-2, $11.53. As an example, the total cost for

first-year transplants includes the first 3 figures

and the last figure in the production cost column

plus its cumulated depreciation of 50 cents per

thousand.

Forest Nursery Practice in the Lake States 111
LITERATURE CITED

(1)

(2)

(3)

(4)

(5)

(6)

(7)

(8)

(9)

(10)

(11)

(12)

(13)

(14)

(15)

(16)

(17)

(18)

112

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1951. METHYL BROIyllDE TO CONTROL WEEDS IN

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1947. COMMERCIAL FERTILIZERS. Ed. 4, 522 pp.,

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1928. SOME ASPECTS OF FOREST GENETICS. JoUr.

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1934. THE USE OF RAPID CHEMICAL TESTS ON SOILS

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FERTILIZER NEEDS. Purdue Agr. Expt.

Sta. Cir. 204, 16 pp., illus.

TiLLOTSON, C. R.

1917. NURSERY PRACTICE ON THE NATIONAL

FORESTS. U. S. Dept. Agr. Bui. 479, 86

pp., illus.

1921. GROWING AND PLANTING HARDWOOD SEEDLINGS ON THE FARM. U. S. Dept. Agr.

Farmers' Bui. 1123, 30 pp., illus.

TiPPETT, L. H. C.

1941. THE METHODS OF STATISTICS. Ed. 3, 284

pp. London.

TouMEY, JAMES W., AND KORSTIAN, CLARENCE F.

1942. SEEDING AND PLANTING IN THE PRACTICE

OF FORESTRY. Ed. 3, 520 pp., illus. New

York.

AND LI, T. T.

1924. NURSERY INVESTIGATIONS WITH SPECIAL

REFERENCE TO DAMPING-OFF. Yale School

Forestry Bui. 10, 36 pp.

TRUOG, E.

1946. SOIL REACTION INFLUENCE ON AVAILABILITY

OF PLANT NUTRIENTS. Soil Sci. SoC.

Amer. Proc. 11: 305-308, illus.

TURNER, HARRY C.

1932. THE CONIFER ROOT WEEVIL. U. S. Forest

Serv. Planting Quart. 1 (3): 10-11.

[Processed.]

1933. FINAL REPORT ON TEST OF THE CORSON SOIL

CAN. U. S. Forest Serv. Planting Quart.

2 (1): 25-28. [Processed.]

1934. SOME NOTES ON THE USE OF SULPHURIC

ACID. U. S. Forest Serv. Planting

Quart. 3 (3) : 5. [Processed.]

1939. ANOTHER COMMENT ON DRILL SOWING.

U. S. Forest Serv. Planting Quart. 8 (3) :

23-24. [Processed.]

UMLAND, CHARLES B.

1946. NURSERY WEEDING COSTS REDUCED BY

MECHANICAL CULTIVATION. Jour. Forestry 44 : 379-380, illus.

U. S. FOREST SERVICE.

1948. WOODY-PLANT SEED MANUAL. U. S. Dept.

Agr. Misc. Pub. 654, 416 pp., illus.

1955. TIMBER RESOURCE REVIEW, IX. APPENDICES SUMMARY OF BASIC STATISTICS.

116 pp., illus. [Processed.]

VOLK, G. M., AND BELL, C. E.

1947. SOIL REACTION (pH). SOME CRITICAL FACTORS IN ITS DETERMINATION, CONTROL,

AND SIGNIFICANCE. Fla. Agr. Expt. Sta.

Bul. 400, 36 pp., illus.

116 Agriculture HandhooJc 110^ Ü, S, Department ofAgriculture
(182) WAHLBNBERG, W. G.

1930. INVESTIGATIONS IN WEED CONTROL BY ZINC

SULPHATE AND OTHER CHEMICALS AT THE

SAVENAC FOREST NURSERY. U. S. Dept.

Agr. Tech. Bill. 156, 36 pp., illus.

(183) WAKELEY, PHILIP C.

1954. PLANTING THE SOUTHERN PINES. U. S.

Dept. Agr. Monog. 18, 233 pp., illus.

(184) WALES, H. B.

1932. MACHINERY IN NURSERY AND PLANTING

PRACTICE. Forest Nurserymen's Conf.

Proc, N. Y. State Conserv. Dept. and

N. Y. State Col. Forestry, 89 pp., illus.

(185) WATKINS, JOHN V.

1940. PROPAGATION OF ORNAMENTAL PLANTS.

Fla. Agr. Expt. Sta. Bui. 347, 54 pp.,

illus.

(186) WELLS, T.

1940. NURSERY PRACTICE AT THE GREEN TIMBERS

FOREST NURSERY. Forestry Chron. 16:

94-98.

(187) WHITE, DONALD P.

1941. PRAIRIE SOIL AS A MEDIUM FOR TREE

GROWTH. Ecology 22: 398-407, illus.

(188) WILDE, S. A.

1935. THE SIGNIFICANCE OF SOIL TEXTURE IN

FORESTRY AND ITS DETERMINATION BY A

RAPID FIELD METHOD. Jour. Forestry

33: 503-508, illus.

(189)

1937. RECENT FINDINGS PERTAINING TO THE USE

OF SULFURIC ACID FOR THE CONTROL OF

DAMPING-OFF DISEASE. Jour. Forestry

35: 1107-1110.

(190)

1946. FOREST SOILS AND FOREST GROWTH. 241

pp., illus. Waltham, Mass.

(191) AND WiTTENKAMP, R.

1939. THE PHOSPHATE AND POTASH STARVATION

OF FOREST SEEDLINGS AS A RESULT OF

THE SHALLOW APPLICATION OF ORGANIC

MATTER. Jour. Forestry 37: 333-335,

illus.

(192) WILSON, J. K.

1937. SCARIFICATION AND GERMINATION OF BLACK

LOCUST SEEDS. Jour. Forestry 35: 241-

246, illus.

(193) WiTTICH, W.

1950. DIE DÜNGUNG DER FICHTENKULTUR. Die

Technik der Fichtenkultur, pp. 25-41,

illus. Hannover, Germany.

Forest Nursery Practice in the Lake States 117
APPENDIX

COMMON AND SCIENTIFIC NAMES OF TREES AND SHRUBS MENTIONED

CONIFERS

Douglas-fir Pseudotsuga menziesii (Mirb.) Franco

Fir, balsam Abies halsamea (L.) Mill.

Hemlock, eastern Tsuga canadensis (L.) Carr.

Juniper, Rocky Mountain Juniperus scopulorum Sarg.

Larch, European -_-- Larix decidua Mill.

Larch, Japanese L. leptolepis (Sieb. & Zuce.) Gord.

Pine, Austrian Pinus nigra Arnold

Pine, eastern white P. strohus L.

Pine, jack P. banksiana Lamb.

Pine, ponderosa P. ponderosa Laws.

Pine, red (Norway) P. resinosa Ait.

Pine, Scotch P. sylvestris L.

Pine, Swiss mountain (syn. Mugho) P. mugo Turra

Pine, western white P. montícola Dougl.

Redcedar, eastern Juniperus virginiana L.

Spruce, black Picea muriana (Mill.) B. S. P.

Spruce, blue -P. pungens Engelm.

Spruce, Norway P. abies (L.) Karst.

Spruce, western white P. glauca var. albertíana (S. Brown) Sarg.

Spruce, white P. glauca (Moench) Voss

Tamarack Larix laricina (Du Roi) K. Koch

White-cedar, northern- _^ Thuja occidentalis L.

BROADLEAVES

Ash, black Fraxinus nigra Marsh.

Ash, green F. pennsylvanica Marsh.

Ash, white F. americana L.

Aspen, bigtooth Populus grandidentata Michx.

Aspen, quaking P, tremuloides Michx.

Basswood, American , Tilia americana L.

Beech, American Fagus grandifolia Ehrh.

Birch, paper Betula papyrifera Marsh.

Birch, yellow B. alleghaniensis Britton

Butternut Juglans cinérea L.

Cherry, black Prunus serotína Ehrh.

Cottonwood, eastern Populus deltoides Bartr.

Elm, American Ulmus americana L.

Elm, rock U. thomasii Sarg.

Elm, Siberian U, pumila L.

Hickory, shagbark Carya ovata (Mill.) K. Koch

Locust, black Robinia pseudoacacia L.

Locust, shipmast R. pseudoacacia var. rectíssima Raber

Maple, red Acer rubrum L.

Maple, silver A. saccharinum L.

Maple, sugar A. saccharum Marsh.

Mountain-ash, American Sorbus americana Marsh.

Oak, northern red Quercvs rubra L.

Oak, white 0. alba L.

Peashrub, Siberian Caragana arborescens Lam.

Poplars-- Populus spp.

Walnut, black Juglans nigra L.

Willow, white Salix alba L.

SAFETY RULES AND PRECAUTIONS

FOR HANDLING, MIXING, AND

APPLYING CHEMICALS

Most insecticides and fungicides as well as some

other sprays and baits contain poisons injurious, if

not deadly, to humans and livestock. Many act

through the skin or lungs as well as through the

digestive tract. In addition, some are flammable

or explosive, or involve other hazards. Enforcing

the following general rules should minimize

accidents with poisons and other hazardous materials (188).

1. Plainly mark both temporary and permanent

containers to show nature of contents (poisonous,

flammable, or the like) and date of purchase

(some chemicals change or deteriorate with age).

Keep dangerous materials tightly closed (unless

their nature requires venting); out of reach of

children, irresponsible persons, livestock and pets;

and in an adequately ventilated storeroom, preferably locked.

2. When mixing or applying poisonous materials, take extreme care to keep them out of

mouth, eyes, nose, and lungs and away from

tender parts of the body. Ordinarily, wear

leather or parafíined-cloth gloves (rubber or plastic

gloves must be used with certain chemicals), and

118 Agriculture Handhooh 110^ U. S. Department of Agriculture
always wear goggles, respirator, or a combination

of the two if the substance requires. If manufacturer specifies, mix substance only in open shed

or outdoors.

3. Prohibit smoking during the mixing or

application of flammable or explosive substances.

4. Burn or bury empty packages and bags that

have contained poisons. Bury unused or discarded materials. When mixing vessels, sprayers,

and the like are washed after use of the more

poisonous substances, empty wash water into hole

in ground, and fill in the hole. Do not burn

empty arsenical containers except in open air.

5. Always wash hands and face thoroughly after

mixing or applying poisonous substances. After

long exposure, bathe and change clothes. Wash

the clothes after each day's spraying operation.

6. Make sure that no poisonous spray material

can in any way get into domestic or livestock water

supplies.

7. If sulfuric acid must be diluted (as for

acidifying soil to control damping-ofï), always

pour the acid, which is the heavier liquid, into the

water. Water poured into sulfuric acid spatters

badly, with serious danger, especially to the eyes.

Only the most responsible and trustworthy

personnel should be allowed to handle chemicals

that are toxic to humans, explosive, or flammable.

It is extremely important that the labels on insecticides, fungicides, or weed killers be read carefully

and then followed. Containers for chemicals,

once emptied, should be stored in a safe place or

destroyed. Surplus mixtures should be buried and

covered with soil. They should not be poured

into streams or ponds where they may endanger

human life, fish, or livestock (37),

Workers handling concentrated acid should be

equipped with goggles, rubber gloves, and acidproof aprons. Acids can be handled safely by

using a 3-gallon crock, carried in a frame by 2

men (fig. 64). Once diluted to a 2-percent solution, it is not particularly hazardous to handle.

Workers should not breathe the fumes of chemicals such as methyl bromide, allyl alcohol (144)y

and chlorobromopropene. They should use special

injectors for methyl bromide as supplied or recommended by the manufacturer of the chemical, and

they should wear masks when handling allyl

alcohol or chlorobromopropene.

The insecticides aldrin, chlordane, and toxaphene are somewhat toxic to man and other warmblooded animals but are not dangerous when

diluted and carefully handled. Concentrated

materials should not be inhaled, swallowed, or

allowed to touch the skin.

Certain insecticides, such as DDT, are harmful

to bees which are helpful in pollinating many

plants. Insecticides generally should not be

Material List

No. Quantity Description

1 2 PCS. 1 X 4 X 52 S4S

2 4 PCS. I"x2"xl2" S4S

3 4 PCS. I"x4"xl2" S4S

4 4 PCS. I"x4"x IZYz S4S

5 2 3/8"xl2" hook bolts S nuts

6 1 3 gal. crock

FiGUBE 64.—Device for handling acids.

Forest Nursery Practice in the Lake States 119
applied to plants in bloom. If spraying is necessary with DDT, it should be done when the

flowers are in the bud stage. To avoid injury to

bees, however, toxaphene can be sprayed in the

early morning or late evening.

Glass carboys of acids should never be removed

from their crates or shipping packages. The glass

containers may break from moderately hard contact with concrete floors or a small piece of gravel

or rock between the carboy and floor. If carboys

must be removed from their containers, they

should be handled on a cleanly swept wooden

platform free from gravel or protruding nails or

screws and preferably with a layer of heavy cardboard under the glass jar.

Some chemicals, such as carbon disulphide, are

explosive. Others, such as chlorates and mineral

spirits, are quite flammable. They must, therefore, be stored in separate buildings or containers

well separated from warehouses and other buildings. At the Griffith State Nursery in Wisconsin

mineral spirits are stored in 50-gallon steel drums

placed on horses along drives at ends of seedbeds

that are to be sprayed that year. Drums are

spotted about 100 feet apart. This method reduces risk of fire to an absolute minimum and also

the time required to fill the sprayers. Some nurseries have special 500- to 1,000-gallon tanks and

pumps for storage purposes.

Lime sulfur should not be used where the spray

may drift onto paint, stonework, or ornamental

stone walks. In such instances oil is preferred as

a dormant spray.

Oil sprays are not recommended for summer use

because the oil may injure the foliage or new

growth of small nursery trees. In dormant sprays,

thorough mixing or emulsification is necessary

before application. Oil emulsions over 4 percent

in strength may cause damage to trees. If

oils or oil emulsions are used, tanks must, in most

cases, be quite free of any lime sulfur residues since

these may break down the oil emulsion.

Copper sulfate, used in preparation of bordeaux

mixture, goes into solution best if used in powdered

form. Quick lime or hydrated lime is used in the

preparation of bordeaux. These materials go into

suspension more readily if rainwater or a water

of low mineral content is used. A common bordeaux mixture used in nursery work is 4-6-50,

containing 4 pounds of copper sulfate, 6 pounds

of quick lime (or 8 pounds of hydrated lime),

and 50 gallons of water. The copper sulfate must

be completely dissolved and the lime thoroughly

in suspension to prevent clogging of the sprayer

and to get a uniform mixture. Sprayers should be

thoroughly cleaned out after use.

Sprayers used for weed or brush killers such as

2,4-D or 2,4,5-T should not be used for spraying

insecticides or fungicides in the nursery because

residues of these particular chemicals may damage

or kill the trees. If it is necessary to use these

sprayers, they should be thoroughly scrubbed out

with soap and water and rinsed repeatedly.

SPRAY FORMULAS FOR INSECTICIDES AND FUNGICIDES

A number of well-tested formulas have been

developed for preparing insecticides and fungicides

(tables 39 and 40). They will prove helpful to

nurserymen in protecting nursery beds as well as

larger trees in windbreaks or natural stands near

the nursery.

MOUSE BAITS

Zinc Phosjphide Formula {52)

Steamed rolled oats 98 pounds

Amber petroleum jelly 10 ounces

Mineral oil 10 ounces

Zinc phosphide 1 pound

The mineral oil and petroleum jelly are warmed

together until they are fluid, but not hot. Zinc

phosphide is added to the mixture and stirred

vigorously. This material is then poured over the

oats and mixed thoroughly. Zinc phosphide baits

are generally effective for about 3 weeks after

preparation.

Strychnine Alkaloid Formula

The bitter taste of strychnine alkaloid sometimes

results in less ready acceptance by certain mice.

The formula is as follows:

Steamed rolled oats 12 pounds

Powdered strychnine alkaloid 1 ounce

Baking soda 1 ounce

Gloss starch ^^ ounce

Water 1 pint

Heavy corn sirup YA pint

Glycerine or petrolatum 1 tablespoonful

The starch is mixed with )i teacup of cold water,

stirred into % pint of boiling water, and cooled until

it forms a thin paste. Strychnine is mixed with

the baking soda, then added to the starch paste

and stirred until free of lumps. The corn sirup

and glycerine or petrolatum then are added. The

mixture is poured over the oats and allowed to dry

before sacking.

CONVERSION FACTORS

This list is useful in experimental work and

empirical test plots, and for conversion of the

United States system of weights and measures to

the metric system:

Length

1 inch

1 foot

1 yard

1 mile

1 square inch

1 square foot

1 square yard

1 acre

1 acre

=-2.54 cm.

= 0.3048 meter

= 0.9144 meter

= 1609.3 meters

Area

= 6.4516 square cm.

= 0.093 square meter

= 0.836 square meter

= 0.4047 hectare

=43,560 square feet

120 Agriculture Handbook 110^ Z7. S, Department of Agriculture
TABLE 39.—Formulasjor insecticides and fungicides ^

INSECTICIDES

Formula

No.

Ingredients Water Sticker or spreading agent

9

10

11

11a

12

13

13a

Lead arsenate 2 to 5 (av. 4) lb

Derris or cube powder (4% rotenone) 2-8 lb

Nicotine sulfate (40% nicotine) 1 pint

Pyrethrum powder (0.8 to 1% pyrethrins) 1 lb

Emulsifiable pyrethrum extract (1% pyrethrins) 1 pint

Derris or cube powder (4% rotenone) 1.5 lb

Oil emulsion (75% oil) 4 gal

Miscible oil (90% oil) 5 gal

Miscible white oils 1 gal

Lime sulfur (10 gal. liquid or 40 lb. dry)

Parathion lib

Tetraethyl pyrophosphate (40% emulsifiable) >^ pt

Aramite 15W, Neotran, or Dimite, 2 lb

DDT (emulsifiable, 25% DDT) 1 qt

DDT (50% DDT wettable powder) 1 lb

Gallons

100 1 pt. of fish oil.

100 ji gal. fish oil.

100 3 lb. solid soap or 6 lb. liquid

soap.

100 Do.

100 None.

100 3 lb. solid soap or 6 lb. liquid

soap.

96 None.

95 Do.

100 Do.

90 Do.

100 Do.

100 Do.

100 Do.

100 Do.

100 Do.

FUNGICIDES

14

15

16

17

18

19

20

21

22

Lime sulfur (2.5 gal. liquid or 6-8 lb. dry)

Bordeaux-copper sulfate 8 Ib., hydrated lime 10 lb

Bordeaux mixture powder 16 lb

Wettable sulfurs

Sulfur dust 3

Puratized agricultural spray 1 to 1.5 pt

Ferbam 1.5-2 lb

Ferbam H lb., wettable sulfur 3 lb

Elgetol Igal

None.

Calcium caseinate 2 lb.

Do.

According to directions on container.

None.

Do.

Do.

Do.

Do.

1 Taken from revised Tree Pest Leaflet 31, Spraying and Dusting to Control Insects and Diseases, by S. F. Potts

and A. M. Waterman (117).

2 According to directions on container.

3 For control of chewing insects, 2 pounds of lead arsenate or 1 pound of 50% DDT powder can be added per 10

pounds of sulfur.

Volume and Capacity

1 cubic inch = 0.554 fluid ounce

1 cubic inch = 16.387 cubic cm.

1 cubic inch = 0.01639 liter

1 cubic foot = 0.02832 cubic meter

1 cubic yard = 0.765 cubic meter

1 pint = 0.5 quart

1 quart (liquid) = 0.9463 liter

1 gallon =3.7853 liters

1 gallon = 231.0 cubic inches

1 quart (dry) = 1.101 liters

1 fluid ounce = 29.5737 cubic cm.

1 bushel = 0.35238 hectoliter

1 U. S. gallon = 0.83268 imperial gallon

1 bushel = 2150.42 cubic inches

1 bushel = 1.24446 cubic feet

1 bushel = 32 quarts (dry)

Weight

1 grain = 0.002286 avoirdupois

ounce

1 avoirdupois ounce =28.35 grams

1 pound =453.6 grams

1 short ton = 907.18 kilograms

1 gram = 0.0353 avoirdupois ounce

1 gram = 15.43 grains

Forest Nursery Practice in the Lake States

Velocity

1 foot per minute

1 mile per hour

= 0.3048 meter per minute

= 1.609 kilometers per hour

Power

1 horsepower

1 horsepower

Weight as Pressure Applied to Area

1 pound per square inch

= 745.7 watts

= 0.7457 kilowatt

70.3067 grams per square

centimeter

Weight as Applied to Volume

1 pound per cubic yard =0.5933 kilogram per cubic

meter

Weight of Various Units of Volume of Water

1 cubic foot

1 cubic foot

1 cubic yard

= 62.424 pounds (at 40° F.)

= 28.317 kilograms

= 764.56 kilograms

Discharge as Flow of Water

1 gallon per minute

1 cubic foot per minute

= 3.7853 liters per minute

= 0.4719 liter per second

121
TABLE 40.—Concentrated-spray formulationsfor use in mist blowers, aircraft, and hand atomizers

Formula

No.

Ingredients

Quantity to make

1 gallon 100 gallons

Gallons to apply

Per

acre

Per

60-foot

tree

Percent of

toxicant

10

11

12

13

14

15

16

17

DDT

Kerosene

DDT, technical

Xylene

Kerosene

DDT, technical

Xylene

Triton X-100

Water

DDT, 50% wettable powder

Water

Benzene hexachloride, emulsifiable, 20%

gamma isomer.

Water

Chlordane, 50 % emulsifiable

Kerosene or water

Chlordane, 50 % wettable powder

Water

Nicotine sulfate

Water

Rotenone, 5% emulsifiable extract

Water

Rotenone, 5% powder

Water

Mineral oil (50 to 90 sec. Saybolt)

Pyrethrum extract, 1% emulsifiable

Water or kerosene

Lead arsenate

Water

Mineral oil (50 to 90 sec. Saybolt)

Refined white mineral oil (45 to 75 sec.

Saybolt).

Refined white miscible mineral oil (50 to 100

sec. Saybolt).

Water

DN-111

Water

Aramite 15W

Water

Soybean oil or linseed oil

Liquid lime sulfur

Klb_.

1 gal_

H lb-.

IK pt.

6^pt.

Klb_.

iM pt.

% oz_.

6Kpt.

1 lb__

IgaL

4 oz_ -

7%pt.

1 pt_.

7pt__

1 lb__

1 gaL

8 oz_-

7K pt.

1 pt_.

7pt_-

1 lb__

7Mpt.

3 oz__

1 pt_.

7pt_-

2 1b__

7% pt

0.4 pt

1 gal1 qt__

3 qt-_

8 oz__

1 gal1 lb__

7% pt.

Hpt--

1 gaL.

40 lb___

99 gal__

50 1b___

15% gal

81% gal

50 lb___

15% gal

Vs gaL82 gaL_

100 gaL

97 gaL_

3/8 gaL

97 gaL _

12>^ gal

87M gal

100 lb__

97 gaL_

6K gaL

93% gal

12M gal

87/2 gal

100 lb__

94 gaL_

2/ gaL

12/2 gal

87/ gal

200 lb._

90 gaL_

5 gal

100 gaL

26 gaL_

74 gaL_

50 lb___

98/ gal

100 lb__

95 gaL_

2/ gaL

100 gaL

2}i

2

2

2

4

2

2

4

5

5

4

6

6

15

6

6

15

/

1

/

/

1

1/

1/4

1

1>1

1/

3/4

1/

1/

.67

6

6

2.5

.6

.6

. 125

21

100

25

6

2

100

1 Taken from revised Tree Pest Leaflet 54, Control of Forest and Shadetree Insects with Concentrated Sprays Applied

by Mist Blowers, by S. F. Potts (116),

Number of Plants Per Unit of Area

10 per square foot ^107.63 trees per square

meter

Temperatures

— 20° F.== —28.9° C.

-10° F.= -23.3° C.

0° r.=:-17.8° C.

25° F. = -3.9° C.

30° F. = —1.1° C.

32° F. =0° C.

40° F. =4.4° C.

50° F. = 10.0° C.

70° F. = 21.1° C.

100° F. =37.8° C.

130° F. = 54.4° C.

140° F. = 60.0° C.

150° F. = 65.6° C.

Formulas:

Degrees Fahrenheit

Degrees Centigrade

° C.Xl.8+32

/° F.-32\

\ 18 )

Volume Per Acre or Per Unit of Area

1 cubic foot per acre

1 cubic yard per acre

100 gallons per acre

100 gallons per acre

1 gallon per acre

1 bushel per acre

1 bushel per 100 square feet

0.06997 cubic meter per

hectare

1.8892 cubic meters per

hectare

8.68 cubic centimeters per

square foot

0.2938 fluid ounces per

square foot

9.353 liters per hectare

0.8708 hectoliter per hectare

379.32 hectoliters per hectare

122 Agy^iculture Handhooh 110^ Ü, 8. Department of Agriculture
Weight Per Acre or Per Unit of Area

1 pound per acre =1.1208 kilograms per hectare

100 pounds per acre = 1.04 grams per square foot

Dollars Per Unit of Area

$1.00 per acre =$2.47 per hectare

SOURCES OF INFORMATION ON

NURSERY PROBLEMS

Nurserymen who have problems with nursery

insects or diseases can get advice on identification

and control by writing to their State agricultural

college or their State nursery inspector who is

invariably a trained pathologist or entomologist.

The inspector may also send out releases on new

quarantine regulations affecting the nursery industry. Advice on nursery disease and insect

problems can also be obtained from the Division

of Forest Disease Research and the Division of

Forest Insect Research, Forest Service, U. S.

Department of Agriculture, Washington 25, D. C.

Advice on control of mammals and birds can

be obtained from the Fish and Wildlife Service,

U. S. Department of the Interior, Washington

25, D. C, or from the Conservation Departments

of the respective States.

Nurserymen who plan interstate shipments of

stock should become familiar with any Federal

and State regulations which may affect their

shipments. This information can be obtained

from the Plant Quarantine Branch of the Regulatory Fl-ogram Section, Agricultural Research

Service, U. S. Department of Agriculture, Washington 25, D. C.

Problems in nursery soils can be referred to the

respective soils departments of the several State

colleges and universities.

SOURCES OF INFORMATION ON

NURSERY MACHINERY, EQUIPMENT, AND CHEMICALS

The nursery industry, as much as possible, uses

equipment and products of stáhdard manufacture.

A list of manufacturers of nursery machinery,

equipment, and chemicals can be obtained from

the Forest Service, U. S. Department of Agriculture, Washington 25, D. C. (Mention of

specific firms does not constitute an endorsement

by the Forest Service or the U. S. Department

of Agriculture.)

Blueprints of specialized equipment, assembled

from manufacturers^ parts, or which must be

built by the nurseryman, can be obtained from

one of several regional offices of the U. S. Forest

Service.

In the North Central Region of the U. S. Forest

Service (comprising the States of Michigan,

Minnesota, Wisconsin, North Dakota, Iowa,

Indiana, Ohio, Missouri, and Illinois) nurserymen

can obtain, at cost, blueprints of certain items

of special nursery equipment or buildings such as

nursery lifters, hand trenchers, root pruners,

tree balers, central warehouses, cold storage sheds,

cone storage sheds, and seed extractories. These

blueprints can be obtained by writing to the

Regional Forester, U. S. Forest Service, Milwaukee,

Wis.

REQUIREMENTS AND PROCEDURES

FOR NURSERY STOCK INSPECTION IN THE LAKE STATES

Each State has its own laws requiring inspection

of trees before they can be sold and removed from

the nursery premises. In brief, these laws provide for an annual inspection of the nursery by the

State nursery inspector or his representative,

define the fees to be so charged, and provide for

the issuance of a certificate of inspection. The

law defines certain species on which there is a

quarantine as regards shipment into the State.

It defines power of the nursery inspector to recommend and enforce destruction of certain pestinfested stock or to enforce its treatment with

appropriate insecticides or fungicides. The law

also provides for tagging of State shipments of

nursery stock and wildings and provides for

penalties for violations of quarantine and other

aspects of nursery regulations. It contains provisions affecting the growing, tagging, and transport of Christmas trees.

Individuals in any of the three Lake States

contemplating growing or dealing in the merchandising of nursery stock can obtain detailed

information on current laws affecting the business

by writing to one of the following agencies:

1. State Entomologist, St. Paul Campus, University of Minnesota, St. Paul 1, Minn.

2. State Entomologist, Department of Agriculture, State Capitol, Madison, Wis.

3. Director, Bureau of Plant Industry, Department of Agriculture, Lansing, Mich.

Those residing in other States can obtain similar

information for their respective States from their

State nursery inspector who is usually located

at the Agricultural Experiment Station or at the

State Department of Agriculture.

Plant quarantine regulations which are in force

on a national basis by the U. S. Department of

Agriculture are available from the Agricultural

Research Service, whose address is listed under

Sources of Information on Nursery Problems.

WHERE TO PURCHASE SEED

A partial list of tree-seed dealers in the United

States and a few foreign countries can be obtained

by writing to the Forest Service, U. S. Department of Agriculture, Washington 25, D. C.

A list of tree-seed dealers in the Lake States

area, or dealers who handle seed native to the

Lake States, can be obtained from the Lake States

Forest Experiment Station, St. Paul Campus,

University of Minnesota, St. Paul 1, Minn.

Forest Nursery Practice in the Lake States 123
WHERE TO PURCHASE NURSERY

STOCK

Nursery stock for reforestation and windbreak

planting can be purchased from State-owned

nurseries in Michigan, Wisconsin, and Minnesota.

It is necessary to make apphcations considerably

in advance, make payments in advance, order a

certain minimum number of trees (usually around

500), and agree not to resell the trees with roots

attached as ornamental stock. Some States

permit use of the trees for resale as Christmas

trees; others do not.

Prices of stock, which is sold at approximately

the cost of production, generally range from $5

to $25 per thousand trees. Price lists can be obtained, along with regulations governing the

purchase, from one of the several addresses listed

below:

1. Division of Forestry, Department of Conservation, Lansing, Mich.

2. Department of Forestry, Michigan State

University, East Lansing, Mich.

3. Division of Forestry, Department of Conservation, St. Paul, Minn.

4. Wisconsin Conservation Department, Madison, Wis.

Nurserymen or others wishing to purchase

nursery stock for ornamental, windbreak, and

Christmas tree planting from private commercial

nurseries can obtain such a list by writing to the

State nursery inspection office in the specific

States. For the three Lake States, write to

the addresses listed under Requirements and

Procedures for Nursery Stock Inspection, p. 123.

U. S. DEPARTMENT OF AGRICULTURE FOREST SEED POLICY (1939)

The U. S. Department of Agriculture has

adopted a forest tree seed policy regarding seeds

of trees and shrubs to be used in reforestation,

shelterbelt, and erosion control planting which

provides guidance for its various conservation

agencies engaged in such work. The policy is

given below:

Recognizing that trees and shrubs, in common

with other food and fiber plants, vary in branch

habit, rate of growth, strength and stiffness of

wood, resistance to cold, drought, insect attack,

and disease, and in other attributes which influence

their usefulness and local adaptation for forest,

shelterbelt, and erosion-control use, and that

such differences are largely of a genetic nature, it

shall be the policy of the United States Department of Agriculture insofar as practicable to

require for all forest, shelterbelt, and erosioncontrol plantings, stocks propagated from

segregated strains or individual clones of proven

superiority for the particular locality or objective

concerned.

Furthermore, since the above attributes are

associated in part with the climate and to some

extent with other factors of environment of the

locality of origin, it shall be the policy of the

United States Department of Agriculture :

1. To use only seed of known locality of origin

and nursery stock grown from such seed.

2. To require from the vendor adequate evidence

verifying place and year of origin for all lots of

seed or nursery stock purchased, such as bills of

lading, receipts for payments to collectors or other

evidence indicating that the seed or stock offered

is of the source represented. When purchases

are made from farmers or other collectors known to

operate only locally, a statement capable of

verification will be required as needed for proof of

origin.

3. To require an accurate record of the origin

of all lots of seed and nursery stock used in

forest, shelterbelt, and erosion-control planting,

such records to include the following minimum

standard requirements to be furnished with each

shipment:

(1) Lot number.

(2) Year of seed crop.

(3) Species.

(4) Seed origin: State—County—^Locality—

Range of elevation.

(5) Proof of origin.

4. To use local seed from natural stands whenever available unless it has been demonstrated

that seed from another specific source produces

desirable plants for the locality and uses involved.

Local seed means seed from an area subject to

similar climatic influences and may usually be

considered as that ^lected within 100 miles of

the planting site ar differing from it in elevation

by less than 1,000 feet.

5. When local seed is not available, to use seed

from a region having as nearly as possible the

same length of growing season, the same mean

temperature of the growing season, the same

frequencies of summer droughts, with other

similar environment so far as possible, and the

same latitude.

6. To continue experimentation with indigenous

and exotic species, races, and clones to determine

their possible usefulness, and to delimit as early

as practicable climatic zones within which seed or

planting stock of species and their strains may be

safely used for forest, shelterbelt, and erosion

control.

7. To urge that States, counties, cities, corporations, other organizations, and individuals producing and planting trees for forest, shelterbelt, and

erosion-control purposes, the expense of which is

borne wholly or in part by the Federal Government

adhere to the policy herein outlined.

O

124 Agriculture Handlook 110^ ZJ, S, Department of Agriculture