Highlights 

"~· ------------------------------------------ ·QiN.J> .. 

An Agricultural Economy 

Iowa is one of the leading agricultural states in the 

Nation . Only 7 percent of the land area is forested -

roughly 2.6 million acres. The eastern counties average 

about 12 percent forest, the western counties about 3 

percent. Nevertheless, forest land has made significant 

contributions to the economy and can make much greater 

contributions through better forest management. 

Forest Ownership 

Farmers own 88 percent of the forest land in Iowa; 

public ownership amounts to less than 2 percent; the rest 

is scattered among many classes of nonfarm, private 

owners. About one-fourth of the farms have some woodland- on the average about 45 acres. Small ownerships 

create difficult problems in development and use of the 

forest resource. 

Sawtimber Volume 

Iowa has about 5 .1 billion board-feet of sawtimber, onethird in oaks, one-fourth in cottonwood, silver maple and 

basswood, one-fifth in elms and the rest, a little less than 

one-fifth, in other species. Pine s<twtimber volume is insignificant, confined mostly to plantations. This timber 

volume is very unequally distributed throughout the 

State. About half of it is found on less than 12 percent 

of the forest area. Looking at it the other way, more 

than half the total forest area contains less than 6 percent of the sawtimber volume. Large areas of overcut 

or neglected woodland are very poorly stocked. 

Growing Stock 

Iowa's forests contain about 1.4 bi llion cubic fee t of 

growi ng stock, ;m aver:tgc of ahout 7Yz cords per acre. 

Onl y one-fourth of this volume is in trees smaller than 

sawtimber size while three-fourths is in merchantable 

sawtimber trees. 

Condition of the Forests 

Most of the forest land in Iowa is inadequately stocked 

and much valuable space is occupied by inferior or cull 

trees. Thirty-nine percent of the forest land supports 

sawtimber stands, 32 percent is in poletimber, and the 

remainder is in seedling and sapling or nonstocked stands. 

Almost 90 percent of the forest area bears mixtures of 

oak and hickory or elm, ash, and cottonwood. In general, 

the volume and quality of timber produced is only a 

fraction of the potential. 

Annual Growth and Cut 

Net growth of growing stock is about three times 

greater than timber cut. Sawtimber growth exceeds cut 

two to one. However, much of the annual increase in 

forest capital is in trees of small size or low quality. Timber cut is concentrated in the larger diameter trees of 

the best quality and most sought-after species. Growth 

and cut are approximately equal in trees 20 inches d.b.h. 

and larger. 

Opportunity for Improvement 

Stand conditions in Iowa are favorable for beginning 

forest management. The increase in volume apparent from 

the growth-cut ratio could, through known forest management practices, result in significant improvement in 

stocking and quality. Management would be hampered 

by the small size of the average forest tract and by inadequate marketing facilities. New outlets for low-quality 

hardwoods are needed to encourage stand improvement 

in some areas. 

Knowledge and skills necessary for growing better 

timber are available to Iowa landowners through the 

services of public and private foresters. The number is 

small compared to the area needing treatment. Much 

economic in formation is needed on the economics of 

growi ng timber under various conditions. Lack of such 

information hampers efforts to motivate the thousands 

of owners of small tracts to apply forest practices on 

their land. 
; , 

.• ,;,~; ;, :.I;''-':-'. :i"Fbrest Resources 

·:.~ of Iowa 

'by 

PH'.rLrF · L. THORNTON, For ester 

entral;)3t~tes Forest Experiment Station 

and 

. 

}AMES T. MoRGAN, Forester 

Lake States Forest Experiment Station 

CONTENTS 

Background 1 

Forest area ..................................................................................................................... 3 

Timber volume ............................................................................................................ 8 

Timber growth and mortality ........................................................................ 13 

Timber cutting ............................................................................................................ 16 

Trends in timber volume ....................................................................................... 1 7 

Wood use and manufacture .............................................................................. 18 

Major significance of survey fi'ndings ...................................................... 23 

Literature cited ............................................................................................................ 26 

Appendix ........................................................................................................................ 2 7 

Tables ................................................................................................................................. 32 

UNITED STATES DEPARTMENT OF AGRICULTURE • FOREST SERVICE 

--o><c!>·------------------------------------·(!)N..o·· 

FOREST SURVEY RELEASE NO. 22 Central States Forest Experiment Station MARCH, 1959 
Preface ··u-@·--------------------------·~ .. 

T HIS report presents the results of a survey of the forests of Iowa, 

a part of the national survey of forest resources. The purposes of this 

survey are: 

1. To make a field inventory of the present supply of standing 

timber. 

2. To find out how fast this supply is being increased through 

growth. 

3. To find out how much it is being diminished through industrial and domestic uses, fire, insects, disease, and other factors. 

4. To determine the present consumption of forest products. 

5. To interpret and correlate these findings to aid m the formulation of private and public forest policies. 

This survey was the first intensive inventory of the forests in Iowa so no 

accurate measure of changes in forest area and timber volumes is possible. 

Resurveys of the forests in the Central States are scheduled for 12-year 

intervals. Reliable comparisons will be possible as these remeasurements 

are completed. 

FIGURE 1-Wooded bluffs and bottomland near McGregor, Iowa. 
Background 

··OJ.o1'Q)·--------------------------------------·(9N..o .. 

Iowa is one of the most important agricultural states 

in the Nation. It leads all other states in corn production 

and ranks second in tash receipts from farm marketing, 

percentage of total land area in farms, and total value 

in farms ( 10) 1 _ 

Forested land in Iowa comprises another valuable 

natural resource in addition to the rich cropland and 

productive pastures. Iowa has almost exactly 1 acre of 

forest land for every one of the 2,621,07 3 people reported 

in the 1950 Census. 

General 

Most of the land surface of Iowa is undulating to 

sharply rolling, frequently dissected by stream and river 

channels. Elevations gradually increase about 1,000 feet 

from the southeast to the northwest corner of the State. 

The Missouri and Mississippi Rivers on the west and east 

borders lie at the foot of relatively hilly and rough terrain. 

The land-use pattern in Iowa is fairly stable at this 

time although there is a certain amount of conversion 

from cropland to pasture, pasture to woodland, and so 

on, going on all the time. Generally, the cropland is confined to the nearly level and moderately rolling areas; the 

pastures are located on the pooter soils and steeper slopes; 

and the forests follow the water courses or occupy rough 

areas (fig. 1). 

1) Numbers in parentheses refer to literature cited, page 26. 

FIGURE 2.-Present areas of fairly continuous forest land. 

Trends in Forest Area 

The forests of Iowa once covered almost 7 million acres 

according to the original land survey made between 1832 

and 1859. Early settlers helped preserve the woodlands 

by controlling wild prairie fires that had periodically 

scarred and killed timber in that region for centuries. 

Moreover, since local use of lumber was relatively small, 

and pine logs could be rafted from Minnesota at low cost, 

Iowa's forests were not heavily cut in the beginning. 

However, as the value of farmland increased forest exploitation began. The appearance of the portable steam 

engine and the rising price of pine from the North resulted in widespread clearing of the hardwood forests. 

Rocky knolls, sandhills, and steep, clay hillsides were 

denuded, pastured a few years, and then abandoned to 

erode and become idle land populated by weeds, brush, and 

scattered trees of low value. Other areas cleared were, 

of course, well suited to agriculture and have been developed into productive pastures and cropland. In the 

clearing process forest land was reduced by about twothirds. 

The present forest acreage seems to be fairly stable; 

the small areas still being cleared are balanced by other 

tracts of open land reverting to forest and by forest invading former prairie land (fig. 2). An example of this 

is the invasion of the bur oak forests into the loess hills 

of western Iowa (fig. 3) . 
Forests and Land Use 

For many years Iowa has been a leader among the 

states in recognizing and working toward the solution of 

agricultural problems. There was an early awareness that 

the maintenance of soil productivity is essential to the 

well being of all Iowans. Soil erosion developed as more 

and more land was plowed in the period following the 

cutting-over of the forests. By 1936 it was found that 

about 87 percent of the total land area in the State 

showed sign of erosion. Moreover, 35" percent of the original surface soil had washed or blown away-taking 

with it thousands of tons of valuable plant nutrients ( 1 3). 

Experience has shown that wise land use on certain 

soils and topographic situations means maintaining a forest 

cover. For example, bottomland areas in Iowa have been 

laboriously cleared, cropped for a few years, and then 

abandoned because of losses from flooding. On the other 

hand, tirriber can be grown successfully on these same 

rich, deep soils because the trees are unharmed by intermittent flooding (fig. 4) . 

Rough areas of easily eroded soils are also well suited 

to forest growth. 

2 

Forests and People 

FIGURE 3.-Forests invading hills 

of Western Iowa - Mon ona 

County . 

Iowans have apparently regarded their forests with 

mixed feelings down through the years. Intense interest 

in fore.stry, evidenced as early as 1874 by the teaching of 

the first forestry courses offered in the United States, has 

been continuous in Iowa for many years. The value of 

trees was well known to those early Iowans making their 

homes in a new land with vast areas of treeless prairies. 

For more than a century individuals, committees, and 

associations have worked steadily to promote forestry and 

tree planting in Iowa. 

Yet, despite this sustained interest it is apparent that 

the thousands of individuals who own 98 percent of the 

forest in Iowa customarily neglect their forest land. Most 

of the woodlands have been subjected to heavy grazing, 

overcutting, high-grading, and general lack of management. 

The average farm woodland in Iowa covers 45" acres--

in most cases an irregularly shaped tract on rough ground 

or along a water course. Evidently most farmers regard 

their wooded acres as little more than a source of shade 

for livestock or a habitat for game animals. When money 
is needed owners cut or sell all trees for which a market 

is available with little or no consideration for the future 

development of the stand. In times of prosperity the 

farm woodlot is usually left almost untouched, or in some 

cases is clear cut for pasture or cropland . 

. On the other hand, planting of trees for shelterbelts, 

windbreaks, and shade is a long established practice in 

Iowa. A survey made on aerial photos showed 230,000 

acres of such plantings-mostly in the prairie areas of 

western Iowa ( 4) . Some of them are more than 100 

years old, some only one row wide. Most of the trees 

planted in recent years are specially selected species that 

are best suited to the rigorous extremes of climate. Some 

of them are good timber species but the average size of 

area planted is small and stocking is frequently low. 

During the past few years, in Iowa as in other states 

across the country, there has been an increasing effort 

to re-emphasize the value of forest land. State, private, and 

federal organizations have joined forces to induce forest 

owners to rehabilitate their forests through protection and 

management. 

• • 

FIGU RE 4.- Bottomland si tes wch as this one being cleared 

are much better suited to growin g timber than to growing 

farm crops . 

• 

Forest Area 

··v-<Q) ----------------------- --------------------- ~·· 

Today, there are 2.6 million acres of forest land in 

Iowa- almost all of it classed as commercial forest land. 2 

In addition to this area there are about 664 thousand acres 

of tree cover occurring in strips less than 120 feet wide 

and in areas less than 1 acre in size which are not classed 

as commercial forest land ( 4). Planted windbreaks and 

shelterbelts account for 3 5 percent of the acreage in these 

wooded stri ps. In general, the forest land in Iowa is concentrated in the eastern and southern portions of the 

State although there is a wide variation among the individual counties (fig. 5). 

Ownership 

Farmers own 88 percent of Iowa's fo rest land-more 

than 2 million acres. About half a million acres are in 

miscellaneous small private ownership. 

V ery little of the commercial forest land in Iowa is 

owned by the public. The State owns about 22,000 acres, 

2) Definitions o f terms used may be found in the Appendix. 

the Federal Government about 13,000 acres, and other 

public ownership is negligible. 

A ccording to the 195 4 Census, there were 193 thousand 

fa rms in Iowa averaging 176 acres in size (fig. 6). A bout 

one-fourth of these farms reported having some acreage 

of woodland- on the average about 45 acres. In the 

bst 20 yea rs there has been a steady increase in farm 

size, with the result that the average woodland area per 

farm has also increased slightly. 

The fact that so nl,;uch of Iowa's forest land is held in 

small tracts by individual owners is one of the greatest 

obstacles holding back the practice of fo restry in Iowa. 

Light partial cuts, stand improvement work, and other 

practices essential to forest man:lgement are hard to sell 

to owners of small woodlots because the profit from such 

practices may not add much to the farm income. But, 

considering the economy of Iowa as a whole, the contribution of 2Yz million acres of we ll-managed forests 

could be significant indeed. 

3 
Forest Types 

Two very general types of forests- the oak-hickory and 

the elm-ash-cottonwood mixtures-occupy 87 percent of 

Iowa's forest land. Other types of local significance are 

the bur oak and the northern hardwoods types. Each of 

these is locally important but only of minor importance 

in the State as a whole. The two other types recogni zed 

in the survey- aspen-birch and the hardwood-redcedarare seldom encountered. 

F IGURE 6. - Percent of total 

farmwoo d s acreage by farm -size 

class. 

4 

FIGURE 'i .-Forest surv ey regions 

and percent of fo re st land by 

counties. 

Forests are classified by type according to the prevalence 

of certain key species in the tree association being considered. Consequently, there is some overlapping of spe-

. cies among the general types recognized. Elm, for example, is fairly common in the oak-hickory type and 

certain oaks are often present in the elm-ash-cottonwood 

type. More specific type designations could not be used 

effici ently in the broad survey reported here. 
The elm,ash,cottonwood type is even more complex 

than the oak,hickory type-virtually every commercial 

tree species in the State is found somewhere in this as, 

sociation as defined in the survey (fig. 7). Generally, this 

type is found along stream beds and moist lower slopesareas more productive than those supporting oak,hickory 

stands. American elm, cottonwood, silver maple, slippery 

elm, and willow are the main components in terms of 

net cubic volume. In Iowa this type ranks first in area, 

volume of sawtimber, cubic volume, and growth potential. 

FIGURE 7.-0a~ stand in "Northeast Iowa. 

The oak-hickory type is usually found on the dry upland 

sites (fig 8). It varies greatly in species composition. White 

oak, northern red oak, and hickory are the three most 

important species in this type in terms of net cubic vol, 

ume. Black walnut is important in terms of sawtimber 

volume and value. Oak,hickory stands containing various 

~pecies mixtures are common in all forested areas of Iowa. 

The bur oak type is fairly common in western Iowa, 

constituting 21 percent of the forest cover in the prairie 

area. Bur oak is well adapted to extremes of drought and 

temperature ; it frequently occurs in pure stands and is 

increasing along the Missouri River bluffs. Bur oak usually 

grows in relatively open stands so that the volume, quality, 

and growth per acre are very low. 

In the heavily forested hills of northeastern Iowa are 

remnants of the northern hardwood forest type. The chief 

species of this type in Iowa are basswood, sug;u maple, 

and northern red oak. Although it makes up only about 

3 percent of Iowa's forest area, it includes some of the 

most valuable stands in th~ State. Successful forest plan, 

tations, chiefly of pines, have been established throughout 

the State. Although fairly numerous they· were not large 

enough in total area to be sampled adequately by the 

rather thin coverage of the Forest Survey. The importance 

of forest plantations for land reclamation, protection, 

and other purposes is well recognized though planted 

stands are not described separately here. 

Physiographic Site 

Topography plays an important role in the develop, 

ment of forests, both directly and indirectly. For example, 

very rough terrain or frequently flooded bottomland may 

be allowed to remain in forest simply because there is no 

other logical use for the land. Also, the slope, exposure, 

and general conformation of the land have a decisive 

effect upon soil moisture and temperature-and thus have 

a direct influence upon the species composition and growth 

of the stand. Level, easily accessible tracts tend to be 

cut over more frequently, especially where farmland is 

marginal for field crops and farmers need extra income. 

In Iowa, 61 percent of the forest acreage occurs on 

rugged topography with sharp ridges and deep ravines 

and gullies. Another 26 percent occurs on broad first or 

second river bottoms, alluvial stream beds and coves. The 

remaining 13 percent is found on level or gently rolling 

terrain with little or no drainage pattern evident. 

The influences of topography upon site quality, stand 

structure and composition, stocking, growth rates, and 

stand size, while not well defined, are significant. 

Site Quality 

Stands of timber reflect the quality of the site upon 

which they occur in much the same way as do cultivated 

crops. On good sites with deep, fertile, well-drained soils, 

trees grow tall and increase in diameter at a relatively 

rapid rate (fig. 9). Trees growing on poor sites-shallow, 

stony, eroded areas, for example- usually are stunted and 

do not grow as large or as fast as more favorably situated 

trees. 

One measure of site quality is the average number of 

16,foot sawlogs produced in a mature tree. In Iowa, on!)' 

15 percent of the forest land was classed as "good" in 

site quality-that is, would produce an average of 3 to 

3Yz 16,foot logs in mature, dominant hardwood trees. 

About half of the forest land is fair quality- 2 to '2Yz 

log sites; and one,third of the area is poor quality-1 to 

lYz logs or less. These estimates, however, tend to be 

conservative because present forest conditions rarely reflect the true potential of the site. · 

5 
Site quality varies to some extent by geographic area--

generally, sites in southeast Iowa are poorest and those 

in northeast Iowa are the best. A relationship is apparent 

between site quality and stand size. Only 11 percent of 

the sawtimber stands occur on poor sites but 5 5 percent 

of the seedling and sapling stands are located on poor 

sites. Also, 28 percent of the sawtimber stands were found 

on good sites in comparison to only 7 percent of the poletimber stands. These figures should be taken as indications 

rather than firm estimates, because of the difficulty of 

determining site potential on the ground. 

Stand Size 

One million acres of forest land in Iowa support sawtimber stands and more than 70 percent of this forest is 

classed as large sawtimber. In the northeast portion of 

the State more than half of the forest land is in sawtimber 

stands. It is significant that 34 percent of the sawtimber 

stands occur on bottomland sites which comprise only 

26 percent of the forest area (fig. 10). On the other 

hand, there is no significant concentration of the poletimber, seedling and sapling, and nonstocked areas on 

any of the physiographic sites recognized. Geographically, 

there is a higher than average percentage of poletimber 

and seedling and sapling stands in southeastern Iowa. 

This may reflect a heavier or more frequent cutting history 

there. N onstocked areas are more common in western Iowa 

and less numerous in the northeast. 

6 

FIGURE 8. - Bottomland f orest. 

··- ~--:· ~-- ~ 

~~~~~~~i,~L!ci~tf Z:i~~~ FIGURE 9.-Large-sawtimber stand on bottom /and site . Th e 

lower parts of the trees are buried in silt. 
FIGURE 10.-Thrifty red oa~·basswood-white ash stand on a good site-Clayton County , Iowa . 

Stocking 

Most of the forest land is poorly stocked- that is, there 

are not nearly enough good growing trees per acre to 

full y utilize the site. H alf a million acres- about onefi.fth of all forest land in Iowa- are less than 10 percent 

stocked with trees of any size. 

Stocking of the forests differs greatly by geographic 

region and by stand-size classes. Sawtimber stands in east· 

an Iowa have the best stocking, although half of those 

areas are not well stocked! Stocking is poorest in the 

poletimber stands in western Iowa-more than 80 percent of this acreage is poorly stocked. 

A poorly stocked forest, like a sparsely seeded field of 

corn, cannot approach either its physical or economic potential. In Iowa, much of the poor stocking is a direct 

result of heavy grazing. Livestock kill small trees by 

trampling and browsing and even cause severe damage 

to large trees. Overcutting and other mistreatment also 

have reduced stocking on large areas. 

7 
Timber Volume 

.. ~.-------------------------------------------·@-u>·· 

The volume of wood in a tract of timber, a standing 

tree, or a primary product such as a sawlog or pulp stick 

can be measured in terms of board-feet or cubic feet or 

both. V olumes in board-feet represent the amount of 

lumber that can be .cut from the stand, tree, or sawlog 

being considered. Consequently, only trees or logs large 

enough to be sawed into lumber are included in this 

volume. Also, losses in sawdust, slabs, edging, trimming, 

crook, and sweep must be deducted in making estimates 

of net board-foot volume. Cubic volume includes all of 

the sound material contained in the main stem of trees, 

to a 4-inch top diameter. Volumes in cull trees and limbs 

of growing-stock trees are treated separately since they 

present special problems in harvesting and utilization. 

Cubic-foot volumes in this report can be converted to 

standard cords by using a factor of 70 cubic feet per cord. 

Board-Foot Volume 

By Species and Forest Type 

There is about 5 .1 billion board-feet of sawtimber on 

the commercial forest land of Iowa-about two-fifths of 

the amount found in each of the nearby states of Minnesota, Missouri or Illinois. One-third of this volume is in 

oak trees, one -fourth is in cottonwood, silver maple, and 

basswood, one-fifth is in elms, and the rest in other species 

(fig. 11) ' 

2,779 million bd.-f l. 

soft hardwoods 302 

basswood 342 

silver mople 462 

collonwood 601 

elms 1,072 

8 

The pattern of species distribution throughout the State 

is very complex. T opography, climate, soils, and past cutting practices combine to produce mixtures of species in 

great variety. For example, in western Iowa 24 percent 

of the sawtimber volume is cottonwood although in the 

remainder of the State that species accounts for less than 

8 percent. In northeast Iowa red oaks comprise 22 percent of the volume but the same species accounts for less 

than 6 percent in the western portion of the State. More 

than 99 percent of the board-foot volume is in hardwood 

species. 

More than half of the sawtimber volume is found in the 

elm-ash-cottonwood type and one-third is in the oakhickory type. The average volume per acre for the entire 

area in the elm-ash-cottonwood type is about 2,300 boardfeet-much more than the corresponding figure of 1,600 

board-feet for the oak-hickory type. 

Another interesting comparison between these two important types is that three-fourths of the board-foot volume in the elm-ash-cottonwood type occurs in large sawtimber stands compared to little more than half in the 

oak-hickory type. The northern hardwoods type shows 

the greatest concentration in large trees-more than 80 

percent of the board-foot volume of that type is located 

in large sawtimber stands. 

FIGURE 11. - Iowa's hardwood 

lumber pile . (Board -foot volume 

in standing sawtimber trees) . 
By Location 

The sawtimber volume in Iowa is very unequally distrib1.1ted. Almost half of it occurs on less than 12 percent 

of the forest land. Conversely, more than half of the 

total forest area contains less than 6 percent of the boardfoot volume (fig. 12). 

Physiographic location influences the distribution of 

timber volume. For example, about 36 percent of the 

board-foot volume is found on bottomland areas that account for only 26 percent of the forest area. Rough upland sites have less sawtimber volume per acre, on the 

average, than bottomland or level upland. 

Productive capacity of the land also shows up in sawtimber volume to some extent-volume tends to be concentrated on the better sites. One-third of the board-foot 

volume in Iowa· is located on "good" quality sites although these sites make up only 15 percent of the forest 

area. One-third of the forest area, classed as "poor m 

site quality, contains only 10 percent of the sawtimber 

volume. 

More sawtimber volume was found in northeast Iowa 

than in any other part of the State. The volume there 

was about two-thirds more than in the western unit and 

one-third more than in the southeastern unit (fig. 13). 

By Tree Diameter 

More than 3 billion board-feet of sawtimber-60 percent of the total-is contained in trees less than 19 inches 

d.b.h. These trees represent the portion of the sawtimber 

growing stock that should be handled most carefully to 

insure future crops of high-quality t:imber. The ·larger 

FIGURE 12. - Sawtimber volume 

and forest area by board·foot 

volume density classes. 

10,000 + 

5,000 - 10,000 

2,500 - 5,000 

1,000 - 2,500 

0 - 1,000 

ones in this class are approaching the period in their 

lives when quality growth will be at its peak. 

About 1.4 billion board-feet of sawtimber is included 

in trees from 19 to 27 inches d.b.h. Many trees of this 

size are economically mature and their annual increase 

in value is slight. 

More than 12 percent of the sawtimber volume-648 

million feet-is contained in trees larger than 2 7 inches 

d.b.h. Most of them are defective to some degree and 

few of them will increase in value if left standing. Generally trees of this size retard the growth and development of smaller individuals that could make use of the 

growing space more effectively. 

The sawtimber volume in soft-hardwoods, cottonwood 

in particular, becomes inc,reasingly important in the 

larger diameter classes. More than three-fourths of the 

cottonwood volume is contained in trees larger than 19 

inches d.b.h. Oak species constitute a greater percentage 

of the sawtimber volume in the smaller diameters. Much 

of the variation in species volume between large and 

small diameter classes is undoubtedly due to cutting practices--both past and present. In easily accessible areas 

trees of preferred species are frequently harvested as soon 

as they reach merchantable size. 

In western Iowa a greater percentage of the sawtimber 

is contained in large trees than is the case in the rest 

of the State. In eastern Iowa about two-thirds of the sawtimber volume is in the 12- to 18-inch d.b.h. class but 

only one-half of the volume in western Iowa is in this size 

class. Most of this difference may be attributed to the 

smaller forest area, the scattered stands, and the lack 

of wood-using industries in western Iowa. 

16% 

19% 

53% 

9 
red ooks 461 

white oaks 

silver maple 

basswood 181 

cotlonwood 166 

elms 396 

other 482 

By Stand Size 

white oaks 382 

silver maple 174 

basswood 83 

cottonwood 116 

elms 377 

other 264 

Trees of sawtimbcr size and quality occur in all kinds 

of forest stands-even on areas classed as nonstocked. 

Although the volume in these trees is included in the 

total volume statistics, it must be recognized that in most 

poletimber, seedling and sapling, and nonstocked areas 

sawtimber trees are too few to be harvested profitably. 

Eighty-four percent of the board-foot volume in Iowa 

is in sawtimber stands, but more than 800 million boardfeet of sawtimber is in other stands that average less 

than 1, 5 00 board-feet per acre. The stands with low 

volumes per acre are not attractive to timber cutters unless other products can be taken with sawlogs in the same 

operation. 

Large sawtimber stands average 4, mo board-feet per 

acre and small sawtimber stands average about 3,400 

hoard-feet. Other stand sizes average from 400 to 600 

board-feet per acre. Average volumes per acre for all 

stand-size classes combined are greatest on bottomland 

sitPs and [past on rough upland areas- they also are 

greatest in northeastern Iowa and least in southeastern 

Iowa. The average board-foot volume per acre for all 

commercial forest land in Iowa is 1,960 board-feet, about 

in the middle of the range for all the Central States. 

By Log Quality 

Sawlog v:Llues depend chiefly upon the percentage of 

better graJcs of factory lumber that can he cut from them. 

About 30 percent of the sawtimber volume in Iowa is 

in Grade 1 or 2 logs- -logs that are most in demand by 

veneer mills and sawmills (7). About one-third of the 

10 

cottonwood 319 

elms 299 

other 219 

FIGURE 13.-Sawtimber volume 

by species and geographic unit. 

volume is in Grade 3 logs that will produce low-grade 

factory lumber. At the bottom of the scale, more than 

one-third of the sawtimber volume is in logs that will 

not meet the present minimum specifications for factory 

lumber but are suitable for railroad ties, structural timbers, and some types of farm construction. Since log 

quality is closely correlated with diameter, much of the 

material that is now low grade could develop into logs 

of high quality if the better trees in the smaller sizes 

were allowed to mature. 

Many factors influence the quality of the logs produced 

by an individual tree. Chief among these are the factors 

that govern the form and branching of the tree-such 

as site, heredity, growing spac~ available, and species 

characteristics. Fire, grazing, insects and disease, in fact 

anything that induces unsound or blemished wood, also 

result in a lowering of the yield of high-grade lumber 

or veneer. 

In Short-Baled Trees 

Iowa, which is on the edge of the range of many eastern 

tree species, has a higher than average population of shortboled trees, that is trees whose trunks are less than 8 

feet long. The volume in trees of this type is estimated to 

be about 420 million board-feet. The elms and white oaks 

are the chief species having these short logs although all 

species are represented to some degree. These trees are 

considereJ as culls-the volume is in addition to the 5 .1 

billion board-feet of sawtimber reported. However, short 

trunks in these trees are often sound and high in quality 

and could he used, in some cases, for stave bolts, veneer 

bolts, or special lumber products. 
Cubic-Foot Volume 

Growing Stock 

Iowa's forest land supports about 1.4 billion cubic feet 

of growing stock-an average of 533 cubic feet (about 

7!/z cords) per acre. About one-fourth of this volume 

is in poietimber trees; the remainder is in the trees making up the sawtimber volume discussed in the preceding 

sections. 

The cubic volume is distributed by species, site quality, 

forest type, physiographic site, stand size, and geographic 

region in much the same way as the board-foot volume. 

Some minor differences exist as a result of the smaller trees 

included (fig. 14) . 

Sawtimber stands average about 1,000 cubic feet per 

acre and there. is very little difference between large 

stand size 

nonstocked 

seedling 8 sapling 

poletimber 

sawtimber and small sawtimber stands. Poletimber stands 

average 327 cubic feet per acre and other stands usually 

have from 110 to 120 cubic feet. Average cubic volumes 

also tend to be highest on bottomland sites and lowest 

on rough upland areas. Forty percent of the cubic volume in soft-hardwood species is found on sites of good 

quality in comparison to only 15 percent of the cubic 

volume in hard-hardwood species. 

About three-fourths of the cubic-foot volume is contained in sawtimber stands and almost 20 percent is found 

in poletimber stands. One-fourth of the cubic volume is 

in pole-size trees, one-fourth in small sawtimber-size trees, 

and one-half in trees 15 inches d.b.h. and larger (fig. 15) . 

Optimum distribution of the growing-stock volume would 

be more nearly achieved if a greater proportion was maintained in trees from about 14 to 20 inches d.b.h. Generally 

trees in that diameter range increase most rapidly in volume and quality. 

55 "lo 

FIGURE 14.-Cubic volume by stand size and area. 

11 
6 8 10 12 14 16 18 20+ 

DIAMETER CLASS (Inches) 

FIGU RE 16.-]\{et cu.hie volu.me m stems of cull trees and limbs of all trees ( commercial species on ly ) by species grou.p . 

12 

elms 

cottonwood 8 

sil ver mople 

other soft 

hardwoods 

white oaks 

red oaks 

other hard 

hardwoods 

Sound-cull trees 

(cen t ra l stem) 

Rotte n -cull trees 

(centre I s t em) 

FIGURE 15'. - Cu.hie vo lu.me by 

tree -diamet er class. 

• L1 mbwood 

(a t i trees) 
Cull Trees and Limbs 

There is more than 600 million cubic feet of sound 

material in cull trees and limbs on commercial forest land 

in Iowa-about 44 percent as much volume as is found 

in the growing stock. Slightly more than one,half of this 

net volume is in the limbs of sawtimber,size trees-both 

growing stock and culls (fig. 16). About one-third of the 

volume is in sound-cull trees and the remainder is in the 

sound portion of rotten,cull trees. About two-thirds of the 

sound volume in rotten,cull trees is in soft,hardwood 

species (elm, cottonwood, etc.) but only about one,half 

of the volume in sound,cull trees is in these species. In 

• • 

western Iowa, the volume in limbs and cull trees accounts 

for 3 5 percent of the total cubic volume in all" trees as 

compared to a similar figure of 2 7 percent in northeast 

Iowa. 

On the average, there are about 3 cords of this sound 

material per acre in addition to the volume of growing 

stock. Most of this. volume is very low in quality and 

consequently, opportunities for harvesting are limited. 

Even when a market for this material exists, harvesting 

usually must be done in conjunction with a partial cutting 

of the growing stock in order to obtain enough volume 

per acre for profitable operation . 

• 

Timber Growth and Mortality 

ooo;..<(!}•---------------------------------------------•0N-o•• 

Sawtimber Growth 

During 195 4, sawtimber trees in Iowa added a net 

amount of 164 million board,feet to their volume. In addi, 

tion, the total net board,foot volume was increased by 

60 million board,feet of "ingrowth" as pole-size trees 

grew into sawtimber size. The total net board,foot growth, 

then, was 224 million board-feet or 4.4 percent of the 

inventory board,foot volume. The average net growth per 

acre of forest land was only 86 board,feet per year, but 

was much higher in sawtimber stands. 

Sawlog quality is closely related to diameter because 

the larger logs have a greater percentage of clear or knot, 

free wood. The higher quality of large logs is indicated 

by the fact that 21 percent of the Iowa sawtimber volume 

in trees 20 inches d.b.h. or larger is in Grade 1 logs but 

only 1 percent of the volume in 12, to 14-inch trees is 

Grade 1. With improved management, the percentage of 

Grade 1 m;1tcrial in the larger trees will undoubtedly 

increase. 

Growing-Stock Growth 

The net growth of the growing stock in 195 4 was 68 

million cubic feet. More than 95 percent of this increase 

was due to growth of growing,stock trees--the remaining increase came from the ingrowth of saplings that 

reached 5 .0 inches d.b.h. The average forest acre in Iowa 

produced only 26 cubic feet of net growth in 1954. \Vell, 

managed and well,stocked stands on average sites in Iowa 

are capable of growing at from 2 to 3 times that rate. 

Vigorous bottomland stands may grow more than 1 Yz 

cords per acre per year. ' 

In most cases, diameter growth is directly correlated 

with tree diameter-that is large trees grow in diameter 

faster than small trees. However, the smaller trees account 

for a greater percentage of the volume growth because 

there are so many more of them. Growth rates also vary 

according to species, topographic site, stocking, and indi, 

vidual tree characteristics such as crown development and 

vigor (fig. 17) . 

Losses in growth result from wildfire, disease, insects, 

grazing, and so on. It is difficult if not impossible to 

evaluate these losses. However, it is possible to estimate 

losses in growth of trees that died and those that deteriorated to a point below the minimum standards of 

merchantability during a certain period of time. It is 

probable that growth losses on living, still merchantable 

trees are much greater than losses on trees that die or 

become culls (fig. 18) . 

13 
Mortality 

Twenty-seven million board-feet of sawtimber was lost 

in 195 4 from natural causes- roughly equivalent to half 

the ingrowth volume gained. Expressed in cubic feet, the 

mortality losses amounted to 8.2 million cubic feetabout 0.6 percent of the growing-stock volume. Almost 

three-fourths of the cubic volume loss from mortality was 

cottonwood, elm, and oak. 

14 

FIGURE 17. - Average annual 

net growth rates of sawtimber 

and growing stoc~. 

Many causes of timber mortality have been noted in 

Iowa. Some of the more important are disease, fire, over, 

topping, windthrow, insects and animals (fig. 19). Losses 

from most of these can be reduced or eliminated as forests 

are brought under management. In managed forests weak 

or dying trees are salvaged and the areas are protected 

from grazing and fire. Diseases such as the oak wilt and 

Dutch elm diseases are present in the State but currently 

are not causing serious trouble. 
.. -. ~;; • 

FIGURE 18.-Defect devel oping from fir e scars. 

disease 

30% 

other 

18% 

-, ~ 

FIGURE 19.-Causes of mortality by percent of cubic 

volume ~illed . 

Ef/ects of Grazing 

Twenty-seven percent of all forest land in Iowa is so 

heavily grazed that no young trees are present to take 

over the sites when the trees there now are cut or die 

(fig. 20). If these areas are to be maintained in forestthey will have to be protected from grazing so that the 

stand will regenerate naturally, or they will have to be 

planted and then protected . 

FIGURE 20.-Severe erosion on heavily grazed woodlot in 

Boone County. 

Eighty percent of the forest land is grazed to some degree. Although most of the area will remain in forest, the 

stocking and quality of trees are adversely aff~cted by 

grazing and the resultant losses in growth from these 

areas are enormous in the State as a whole. Livestock 

raising is important on Iowa farms. The cattle get some 

fo rage from woodland pasture but studies have shown 

the forage value to be small compared to that of improved 

bluegrass pasture ( 5) . The relative profits obtainable from 

grazing and timber growing on timber sites have not been 

established. It is evident, however, that if quality hardwood timber is to be the main crop livestock should be 

kept off the land. 

15 
Timber Cutting 

.. ~·-------------------------------------------·~ .. 

Timber cutting reduced the growing stock in the for, 

ests of Iowa by an estimated 22 million cubic feet in 1953 

-about 1.6 percent of the cubic,volume inventory. Jn, 

eluded in the timber cut was 2 percent of the standing 

sawtimber or about 102.5 million board,feet. These timber, 

cut figures include only the volumes cut from commercial 

forest land and do not include volumes produced from 

noncommercial species, dead or cull trees, or limbwood. 

Merchantable material lost in logging and milling is included as well as the volume of wood that actually is 

developed into a finished product. 

About 5 percent of the commercial forest area in Iowa 

is cut over annually; cutting is distributed fairly evenly 

throughout the State. Some areas are clear,cut, a few 

are cut to leave a more thrifty stand, but the majority are 

"high,graded"-only the best trees are harvested. In addi, 

tion, some timber is removed from noncommercial forest 

land such as narrow wooded strips. Salvage of dead trees, 

cull trees, and limbwood produces significant volumes of 

wood products. No accurate estimate of these volumes 

is available. 

An estimated 4 percent of the sawtimber volume cut 

was left in the woods as logging residue. Some of this 

volume could have been saved by better felling and buck, 

ing practices. However, some losses from breakage and 

other causes are unavoidable. 

About half the timber cut came from the fon;sts in the 

northeastern section and almost 40 percent came from 

the southeast. Western Iowa contributed only about 10 

percent of the timber cut. General observations indicate 

that cutting on noncommercial forest land was most prev, 

alent in western Iowa. Twice as much volume was cut from 

poletimber trees in southeast Iowa than anywhere else. 

Northeast Iowa, however, accounted for almost twothirds of the timber cut from trees 19 inches d.b.h. or 

larger. These geographical variations in timber cutting 

are closely related to characteristics of the inventory vol, 

ume discussed previously, and to available markets. 

About three,fourths of the timber cut in Iowa comes 

from oak, cottonwood, and elm trees according to several 

independent studies in recent years. Maple, black walnut, 

and basswood were the next three most important species 

in terms of the volume of timber cut (fig. 21) . The proportion of volume cut from poletimber trees did not 

vary significantly by species. The distribution of the 

species throughout the State, of course, dictates to some 

extent what species are cut. 

16 

Timber cutting tends to be concentrated on the larger 

diameter trees. For example, although only about half of 

the inventory volume is in trees 15 .0 inches d.b.h. and 

larger, almost two,thirds of the timber cut came from 

trees of that size. 

Species and quality of timber to be cut have a strong 

influence upon the logging possibilities on specific tracts. 

Veneer,log buyers, for example, are willing to harvest a 

much lower volume per acre than buyers of less valuable 

products. Generally, lower stumpage values make neces, 

sary a greater concentration of merchantable volume to 

attract timber operators. 

oaks 

45% 

FIGU RE 21.-Species of timbe r cut. 
Trends in Timber Volume 

··~·-------------------------------------------·~ .. 

Both the board-foot and cubic-foot volumes in the forests of Iowa are increasing steadily. The net volume 

of sawtimber growth was more than twice the volume 

of sawtimber harvested. The net board-foot increase, 

after deducting timber harvested and mortality, amounted 

to 2.4 percent of the standing sawtimber volume-an 

average of 47 . board-feet per acre per year. However, 

the characteristics of the forests and of timber harvesting lead to wide variations between specific. areas of the 

State. 

The increase in volume is concentrated to a large degree on trees less than 15' inches in diameter. This, of 

course, is because the average diameter of trees harvested 

is significantly greater than the average diameter of all 

trees. In fact, slightly more volume was harvested from 

trees 20 inches d.b.h. and larger than was added to trees 

of that group by growth (fig. 22) . 

It is likely that, if timber harvesting practices remain 

fairly constant and no catastrophic losses occur, there 

will be a continuing buildup of the sawtimber volume 

in Iowa during at least the next 10 to 15' years. It is likely 

also that the total volume of high-quality sawtimber will 

FIGURE 22.-Comparison of annual growth and cut. 

gradually increase in that period. On the other hand, it 

is clear that the percentage of volume in the most desirable species, such as red oak and black walnut, will decrease steadily because these species are more sought after 

by the loggers. Also, a larger area will be occupied by 

cull or defective trees that are repeatedly passed over in 

logging operations. 

Renewed interest in forestry, coupled with the various 

programs of assistance and guidance for forest land owners, 

may result in continuing impi::ovement in the forest situation. Much of the forests of Iowa are in formative stages 

where forest management can have a measurable effect 

upon stocking, growth, structure, and composition in a 

relatively short period. 

Cutting practices could change significantly in a few 

years and alter the outlook for timber volume in the 

future. The increased use of hardwood species for pulp, 

for example, could have a very strong influence upon the 

forests within hauling distance of pulpwood-using plants. 

The development of pulpwood markets, however, is still 

too recent to give firm indications of what their longtime 

influence will be. 

17 
Wood Use and Manufacture 

··~·---------------------------------------- --·0N.o·· 

The forests of Iowa contribute only about one-third of 

the volume of wood used in manufacture in the State 

each year. Softwoods make up more than 80 percent of 

the lumber volume used in the State and nearly all of 

the softwood volume is imported from western states. 

About 80 percent of the imported hardwood volume comes 

from the southern states. Most of the pulpwood, fuelwood, and miscellaneous forest products used in Iowa originate within the State. 

The Lumber Industry 

Sawmills have been active in Iowa almost since the 

first settlers arrived. Pine logs from Minnesota and Wisconsin were rafted down the Mississippi River and hauled 

ashore to sawmills at river towns like Dubuque and Clinton. Most of the lumber used in building the first prairie 

towns came from these mills and was sawed from these 

imported logs. 

18 

Today Iowa is dotted with sawmills from the Mississippi to the Missouri River. A recent listing shows a 

total of more than 1,000 (fig. 2 3) (2). Most of these 

mills are small and many operate intermittently throughout the year (fig. 24). About 96 percent of the mills show 

an individual production of less than 200,000 board-feet 

per year- about 2 months' work for a 3-to-5 -man crew. 

Some of the smaller ones are operated for convenience 

of the owner, or for custom sawing, and many are portable. 

Lumber production in Iowa reached its peak around 

1890 when more than 600 million board-feet were produced annually. It dropped rapidly in the next 30-year 

period, reaching a low annual production of from 10 to 

15 million board-feet at the end of the first World War. 

Since then there has been a gradual, long-term, upward 

trend. Studies indicate that about 6'i million board-feet 

of lumber were produced in 195" 3 from logs cut in Iowa 

forests (fig. 25) . 

F IGURE 23. - Distrib ution of 

Iowa sawmills, 19 52. 
About two-thirds of the annual cut of sawtimber in 

Iowa goes into sawlogs for the production of lumber and 

crossties. Except for fuelwood, which takes 20 percent 

of the sawtimber cut, each of the other uses for sawtimber takes less than 5 percent of the cut. 

The sawlogs are worth about 2V4 million dollars delivered at the mills; in the standing trees, they are worth 

about 1 million dollars; the rough lumber and ties sawed 

from these logs are worth from 4 to 5 million dollars (fig. 

26). There is, of course, a wide range in the value making up these averages; species, quality, economic factors, 

and other influences determine these values for each particular case. Most of the lumber produced in Iowa is 

sold rough and green for local use on farms or in the 

manufacture of wood products that do not require clear 

lumber (fig. 27). Over 600 wood-using industries or 

buyers of wood products, excluding sawmills, were reported to be located in Iowa in 19 5 2 ( 3) . 

Oak lumber accounted for about 40 percent of the total 

produced in Iowa in 1953. Another 45 percent was made 

up of cottonwood, elm, and maple (fig. 28). The quality 

and size of logs cut for lumber have not been accurately 

determined. However, experience in nearby states indicates that the average quality of the logs sawed for lumber is much higher than for those remaining in the standing timber. 

The Veneer Industry 

The second most important timber market for the 

hardwoods of Iowa is the veneer industry. In 195 3 about 

5 percent of the annual cut of sawtimber-size material 

was consumed at veneer mills. Most of this volume is 

exported-in fact, according to a survey of the veneer 

industry in 1956, three-fourths of the volume of veneer 

logs cut in Iowa was shipped to mills outside the State (9). 

Almost all of the veneer-log harvest is used to produce 

commercial or face veneer although a small amount is used 

in container manufacture (fig. 29). 

FIGURE 24.-Smal! sawmill in Iowa. 

Veneer-log buyers search continually for high-quality 

black walnut trees or logs. Frequently they purchase 

individual trees in order to obtain one or two prime logs, 

but get most of their supply from sawmill operators or 

sawlog buyers that hold veneer-quality logs for resale. 

Prices paid for top-quality-veneer logs may be much higher 

than those paid for the same volume of ordinary sawlogs, 

but top quality is very hard to judge in the standing tree. 

About three-fourths of the veneer-log harvest is cut 

from black walnut, oak, and maple trees (fig. 30). 

The supply of veneer-quality logs in Iowa may be expected to diminish gradually in the next 10 to 15 years. 

The young stands building up today do not contain as 

many black walnut trees as did earlier forests, and stand 

conditions generally are not favorable for the development 

of trees of high quality. If better stocking and improved 

harvesting practices become more universal in Iowa this 

trend could be reversed. Also, new techniques of manufacture and shifts in consumer preference may result in a 

veneer-log market for more species and with less rigid 

specifications. 

FIGURE 25.-'Trends in Iowa lumber production. 

19 
The Pulpwood Industry 

The nationwide increase in the use of hardwood species 

for pulpwood has been reflected in Iowa. Recent canvasses of pulpwood-using plants in the north central region indicate that the harvest of pulpwood in Iowa has 

increased to six times the 3,200 cords reported in 195'3 

(8). N ew pulping facilities established at Dubuque and 

Fort Madison have spurred this increase. Soft-hardwoods, 

such as cottonwood, willow, sycamore, and soft maple, 

are most in demand for pulpwood, although oaks and 

other hard species are accepted at some plants. 

fIGl:RE 27.-Farm building made from native lumber. 

20 

FIGURE 26. - Cross-ties from 

Iowa timber. 

FIGURE 28.-Cottonwood logs - Pottawattamie County. 

Although the market for pulpwood is important mainly 

within hauling distances of pulpwood-using plants, it is 

expected that this market will become more important in 

future years. It is possible to cut pulpwood from material 

not suitable for most other forest products. Much of the 

sound volume in cull trees, limbs, and small poletimber 

trees can be used for pulping. This makes possible forest 

management practices usually too expensive to put into 

effect in other areas. 

Naturally, pulpwood operators would prefer to harvest 

straight, clean poletimber of fairly large diameter in order 

to minimize logging costs. An adjustment in stumpage 

price, a bonus paid at the plant, or some other inducement is required to move significant quantities of pulpwood cut from cull trees or limbs of trees harvested for 

sawlogs. 
FIGURE 29.-Blac~ walnut veneer logs - Clayton County, 

Iowa. 

Other V ses for Iowa Timber 

Several other uses for wood from Iowa's forests are 

worthy of mention although determination of the volumes 

used is more difficult and larger errors of estimation are 

unavoidable. 

An estimated 2.4 million fence posts were harvested in 

Iowa in 195 3, but only about half were cut from the growing-stock volume. Dead and cull trees and trees on nonforest land made up the remaining volume of fence posts. 

Oak, elm, and miscellaneous species are cut for fence posts. 

Some are treated with preservatives to extend their useful life. Some farmers alternate wooden fence posts with 

metal ones to provide added strength. When markets 

exist, fence-post cutting is a good way to improve stand 

conditions if trees are selected carefully (fig. 31). 

In southeast Iowa a small amount of timber is cut for 

cooperage. Small, portable stave mills provide a temporary 

local market for high-quality oak logs. Although the impact of their operations on the total resource of Iowa is 

small, stave mills do represent an additional outlet for the 

better quality timber in the larger diameter classes. 

An estimated 383 thousand cords of fuelwood were 

produced in Iowa in 195 3 but only 31 percent of that 

amount was cut from the growing stock. Still, 20 million 

board-feet of merchantable sawtimber went into fuelwood. 

Twenty-seven percent of all fuelwood harvested came 

from dead trees; 20 percent was c.ut from cull trees and 

limbs, and 16 percent was cut on nonforest land. Oak 

and elm accounted for about half of the fuelwood harvested from the growing stock. Fuelwood provides an 

outlet for low-quality material that usually has no other 

value. Consequently, the harvesting of fuelwood can also 

be tied in effectively with stand improvement work. 

Wood V sed in Manufacturing 

Wood is a basic raw material in hundreds of manufacturing plants in Iowa producing scores of different 

types of wood products. The 195 4 Census of Manufacturers includes major wood-using industries in a "Lumber 

and Wood Products" category (11). This group includes 

large sawmills, planing mills, veneer mills, millwork plants, 

wooden container plants, miscellaneous wood product 

manufacturers, and other related establishments. In Iowa, 

the most important users of wood for manufacture are 

the millwork plants and the container industries. 

Plants in the "Lumber and Wood Products" category 

employed 16,586 people or 10.3 perc,ent of all employees 

in Iowa in 19 5 4. This same group also accounted for 8. 6 

percent of the State's payroll-about 55 .2 million dollars. 

The value added by manufacture, that is the value of shipments minus the cost of materials, fuels, etc., amounted 

to 81.4 million dollars. 

FIGURE 30.-Species of veneer logs harvested- 1956. 

21 
Hundreds of other manufacturers in Iowa use wood 

as a raw material but are not included in the basic "Lumber and Wood Products" group. They use wood either in 

their product or in shipping or in both. An indication of 

the significance of these establishments in the overall wooduse picture is afforded by a 1948 analysis of wood use in 

manufacture in the United States (6) . At that time, for 

the entire United States, 46 percent of the total volume 

of wood used in manufacture was consumed at such 

plants. Examples of the more important types of industries in this group are: Furniture, partitions, shelving, 

railroad car manufacture and repair, mortician's goods, 

22 

FIGURE 31. - Fence posts from 

trees removed in thinning 

Amana Experimental Forest. 

and refrigerator shipping. It is apparent that the use of 

wood plays an even more vital role in the economy of 

Iowa than is indicated by the preceding paragraph. 

A recent study in Iowa ( 3) points out why most woodusing industries in Iowa must im'Port lumber. They have 

found through experience that Iowa lumber is less satisfactory because it is not surfaced or dried sufficiently, is 

not accurately manufactured, or is not available in the 

species, quantities, or grades required. If more . and better 

timber is to be produced by the forests of Iowa, it is 

evident that the manufacture and marketing of lumber 

from that timber must be improved also. 
Major Significance of Survey Findings 

··o..s-<Cl·-------------------------------------------·~ .. 

Although Iowa is primarily an agricultural State, its 

industries require much more timber each year than it 

produces on forest land within the State. In Iowa, as in 

the Nation, a continuing expansion of the population, 

coupled with industrial growth, may be expected to increase timber requirements greatly during the coming 

years. The recent Timber Resource Review (TRR) 

showed evidence of future demand for forest products 

exceeding the amount that could be produced at present 

levels of forest practice ( 12) . 

However, timber production is by no means the only 

use and value of Iowa's forests. Costly experience in the 

past has proved that forest cover must be maintained on 

some areas in the State to prevent soil erosion. Another 

important value of the forest acres, although most diffi, 

cult to measure by monetary standards, is their use for 

recreation. The rising population, together with a conI 

tinuing increase in leisure time and disposable income, 

points to an ever-increasing use of the forests for this 

purpose. 

The current excess of total timber growth over cut 

is a favorable situation in which to develop more satis, 

factory stand structure and to stimulate growth. However, 

it is not at all an automatic. improvemept merely because 

the total timber volume increases annually (fig. 32) . The 

average forest acre in Iowa now has about 39 square feet 

of basal area (basal area-a convenient measure of stock, 

ing-is the sum of the cross-sectional area of tree stems 

measured 4Yz feet above ground level). As a very general average, well,stocked stands in Iowa should have 

something like 95 square feet of basal area per acre ( 1). 

Therefore, the average stocking needs to be more than 

doubled to provide a base for maximum growth. Eco, 

nomics may dictate greater or less stocking for individual 

stands. 

Optimum basal area 

distribution --i---+---+---1---+--+--l---+---+-----.--+---+c--

FIGURE 32.-0ptimum and actual basal area per acre by diameter class. 

I 

I 

I 

\ 

23 
With present cutting practices, any increase in average basal area per acre will occur in trees smaller than 

20 inches in diameter. Board-foot growth of larger trees 

is held down by concentration of cutting in the larger 

diameter classes. Commercial clearcutting, despite the 

resultant stand deterioration, is an established practice 

used by loggers and woodland owners primarily interested 

in immediate financial returns. The forests of Iowa will 

benefit most at this time if the indiscriminate cutting common today is discouraged as much as possible. In time, 

if protected from destructive cutting, most stands will 

gradually build up until they are well enough stocked 

to support periodic partial cuts. 

Protection of the forests from fire, insects, and disease 

is another way that the productivity and overall values 

of the forests can be increased significantly. The best 

timber-cutting practices are futile when a stand is periodically or continuously damaged by destructive agents. 

When wood-rotting fungi become established in a tree, 

through fire scars, insect damage, or other causes, the 

tree becomes a candidate for mortality or salvage. Uncontrolled fires continue to be a threat to the forests in 

eastern Iowa, though only 1, 119 acres of forest land 

were burned over in Iowa -in 195 4. 

Although some idle land will slowly become forested 

if left undisturbed, establishment of a productive forest 

24 

on bare land is best accomplished by planting (fig. 3 3). 

Approximately 46,000 acres of forest plantings have been 

undertaken in Iowa to date, but only about 14,000 acres 

of acceptable pb.ntations are on commercial forest land 

( 12). Many plantings are of less than 1 acre in size and 

thus do not qualify as commercial forest land. 

Poorly stocked seedling and sapling stands can· be improved by planting trees in the openings so that all of 

the growing space is utilized. Young stands of inferior 

species can often be improved by underplanting trees 

with more desirable characteristics. The State forest nursery at Ames, operated by the State Conservation Commission, produced 441,000 trees in 195 5. Three commercial forest tree nurseries are also located in Iowa. 

Good forest management is handicapped in many cases 

by inadequate markets or a lack of information concerning marketing methods, prices, or the location of timber 

buyers. In general, good-quality timber finds a ready market if there is enough volume to interest a buyer. Marketing lower grade material, however, requires an intensive 

effort by a well-informed seller or agent and even then 

may be unsuccessful. A continuing campaign to improve 

products and to acquaint timber owners with basic marketing practices, should do much to increase interest in 

and returns from their forest land. 

FIGURE 33. - Seven -year, old 

jac~ pine planting - Monona 

County . 
Forest owners often can increase income from timber 

harvesting by selecting, cutting, and transporting logs 

to a market or shipping point after a sale is arranged. 

Here too, much educational work is needed to promote 

good harvesting practices. Log cutting alone can significantly influence the financial returns of a harvesting operation. Farmers frequently have the necessary equipment and some can provide enough labor to undertake 

their own logging. 

Several agencies in Iowa have programs designed to 

assist woodland owners and to stimulate application of 

forestry principles and practices. The Division of Lands 

and Waters of the Iowa Conservation Commission has 

an active forestry organization. Six farm-forestry districts have been set up in the forested areas of the State 

under the Cooperative Forest Management Act of 1950. 

Foresters working in these districts assist owners in appraising· and marketing timber and also advise and aid 

farmers in managing their woodlands. 

The Agricultural Conservation Program of the United 

States Department of Agriculture also actively aids woodland owners. Upon approval of county Agricultural Stabilization and Conservation Committees the Federal Government will share in the cost of planting trees, improving stands of timber, and protecting woodland from graz-

;ng. In 1956 this assistance to Iowa woodland owners 

amounted to about $12,000-about 97 percent of this 

amount was cost-sharing in tree planting. The Soil Conservation Service includes advice to farm woodland owners 

as a part of farm-planμing activities. 

Private consulting foresters also assist woodland owners 

in forest management or timber marketing. They sometimes serve as the agent of absentee owners or manage industrial forest tracts. 

An Extension Forester maintains an office at the Iowa 

State College of Agriculture at Ames. His work, primarily on a statewide basis, is intended to improve the 

management of forests in the State through demonstration 

and education. County Extension Directors carry on this 

work at the local level. 

Research in forestry and related fields is conducted by 

several organizations in Iowa. The Iowa Agricultural Experiment Station at Iowa State College, conducts investigations in all aspects of agrifulture including forestry. 

The Central States Forest Experiment Station maintains 

a research center at Ames in cooperation with the college 

and an experimental forest in cooperation with the 

Amana Society. 

Almost all of the agencies concerned with forestry 

activities in one way or another help to bring better 

forestry practices to the attention of woodland owners 

by demonstrations, field days, tours, meetings, motion 

pictures, and printed materials. 

Even under the best possible treatment many years will 

be required before the bulk of forest land in the State 

can approach its potential productivity. Continuing progress in the establishment and improvement of forest management practices together with improved marketing opportunities will be necessary if the forests of Iowa are 

to contribute their full share to the State's economy. 

25 
Literature Cited 

·~·------------------------------------·~ .. 

(1) CAMPBELL, R. B. 

195 5. Manage your farm woodland for greater 

profit. Agr. Ext. Serv., Iowa State College. Pamphlet 217, 8 pp. illus. 

(2) GETTY, R. E. 

1953. The sawmills of Iowa. Agr. Ext. Serv., 

Iowa State Col., Pamphlet F56, 24 pp. 

illus. 

(3) GETTY, R. E. 

195 3. The wood-using industries of Iowa. A gr. 

Ext. Serv., Iowa State Col., Pamphlet 

F57, 16 pp. 

(4) ~R TONG, A. L. and MOESSNER, K. E. 

195 6. W ooded strips in Iowa. Cent. States Forest Expt. Sta. Forest Survey Release 21, 

15 pp. illus. 

(5) IOWA AGRICULTURAL RESOURCES CONSERVATION 

GROUP 

1953. Iowa agricultural resources conservation 

program. Unpublished report. 98 pp. 

(6) MERRICK, G. D. 

26 

1951. W ood used in manufacture-1948. U. S. 

Forest Service Forest Resource Report 2. 

66 pp. 

(7) MORGAN, J. T. 

195 5. Log grades of Iowa timber. Lake States 

Forest Expt. Sta. T echnical N ote 443 . 

2 pp. 

(8) THORNTON, PHILIP L. 

1957. Pulpwood production continues to increase in the Central States. Central 

States Forest Experiment Station. Sta. 

Note 104. 2 pp. 

(9) THORNTON, PHILIP L. 

1957. V eneer-log production and consumption 

in the Central States-1956. Cent. States 

Forest Expt. Sta. Sta. N ote 11 2. 2 pp. 

(10) u. S. BUREAU OF THE CENSUS 

1956. U. S. Census of Agriculture; 1954. Vol. 

1-part 9. 258 pp. 

(11) u. S. BUREAU OF THE CENSUS 

195 6. U. S. Census of manufacturers: 195 4. 

State Bu!. MC-114 ; Iowa. 12 pp. 

( 12) u. S. FOREST SERVICE 

1958. Timber Resources for America's Future. 

Forest Resource Report 14. 713 pp. illus. 

( 13) WAL KER, R. H., and BROWN, P. E. 

1936. Soil erosion in Iowa, A gr. Exp. Sta., 

Iowa State Col. Special Report 2. 47 pp. 

illus. 
Appendix 

··~·-----------------------------------------·~·· 

FOREST SURVEY PROCEDURE 

The field inventory of the forests of Iowa was made 

during the period November 195 3 to August 195 4. This 

task involved office study of aerial photographs and field 

examination and measurement of randomly selected forest 

and non-forest plots. 

Area Estimates 

The percentage of forest land was obtained by placing 

a transparent sheet marked with uniformly spaced dots 

over aerial photographs and counting the number of dots 

fa lling on forest and nonforest areas. The percentage of 

forest dots in a county, multiplied by the total county 

area gave a preliminary estimate of the forest area. This 

was later adjusted after field examination of selected plots 

showed how many plots had changed from forest to nonforest and vice versa since the date of aerial photography. 

Systematically selected dots falling on forest land were 

marked on the photographs. The acre surrounding each 

marked dot was examined stereoscopically and was classifi ed by stand-size class according to height, crown width, 

and number of trees on the plot. 

Plots to be examined in the field were randomly drawn 

but the selection was weighed- more of the larger stand· 

size classes were selected than the smaller. Crews of two 

men located these points on the ground and established 

a 1 /5 ·acre circular plot at each point. Such data as tree 

species, size, log quality, cull, and growth of trees were 

recorded. 

The following tabulation gives the number of dots and 

plots .examined for the State as a whole. 

Number of photo dots counted for forest· 

area determination 

Number of plots stereoscopically examined 

on photos 

Number of forest plots field examined .. 

Volume Estimates 

27 1,224 

3,2 )9 

7ll 

Sawtimber volume-The gross board-foot and cubicfoot volume tables used in the Iowa survey were based 

upon the Mesavage·Girard form-class tables. Average 

form classes were computed from measurements obtained 

from 707 trees selected randomly on the field plots. Commercial species were segregated into 6 groups on the basis 

of similar form-class characteristics and separate gross 

cubic-foot and board-foot volume tables were prepared 

for each group. The average form class of all trees 

measured was 77. 

The upper stem volume of all sawtimber trees was 

computed from field estimates made for each sawtimber 

sample tree. This volume, expressed in cubic feet, includes the portion of the bole or central stem between 

the merchantable top and a minimum top diameter of 

4.0 inches inside bark. One net table was used for all 

hardwoods since analysis of data showed almost no difference among species or groups of species. 

The volume in limbs of hardwood sawtimber trees was 

also computed from field estimates made for each sample 

tree. Limbwood is the sound material in tops and limbs 

not included in the sawtimber or upper stem portions of 

the tree. The minimum diameter inside bark is 4.0 inches, 

also. Here again, one net table for all hardwood species 

was found to be sufficient. 

The merchantable height and diameter at breast height 

were measured on 275 randomly selected poletimber 

sample trees on the field plots. Analysis of these data 

resulted in separating all hardwood species into either a 

" high" volume group or a " low" volume group. N et 

cubic volume tables were prepared for these groups of 

species having similar diameter-height relationships. 

Eastern redcedar data were inadequate from the Iowa 

field work so a volume table based on data collected m 

other Central States was used for this species. 

Cull Estimates 

Allowance for defect in merchantable sawtimber trees 

was determined by estimating sound and rotten board-foot 

cull in 1,4·7 4 sample trees. Curves of cull percent over 

diameter classes were prepared, species with similar cull 

percents were grouped, and a weighted cull percent was 

established for each species group and diameter class. 

A few species- white oaks and hickory-made up a " low· 

cull" group and the other species were included in a 

" high-cull" group. Cull percent deductions applied to 

the gross board-foot volume tables ranged from 2.9 to 

9.0 percent depending upon species and diameter-class. 

The cubic-foot cull in sawtimber trees was estimated 

in a similar manner except that only rotten or unsound 

defects were considered. These deductions ranged from 

0.6 to 4.0 percent when applied to the gross cubic-foot 

volume tables. 

The average cubic-foot deduction for unsound defects 

in poletimber sample trees was less than 0. 5 percent. 

Poletimber growing stock only includes trees expected 

to be merchantable as sawtimber at some future date. 

Estimates of the cubic volume of sound material in 

cull trees were also computed from sample tree data taken 

27 
on the field plots. Cull trees were classified ·into 4 distinct groups depending upon the characteristics that eliminated the tree from the growing stock volume. Sample 

trees in each of these groups indicated the volume deduction to be applied to the gross volume table used; 

these deductions ranged from 0 to 80 percent. Separate 

volume tables for upper stem volumes (in this case the 

volume between 8.0 inches and 4.0 inches d.i.b. in the 

central stem and limbwood volumes) were prepared for 

cull trees. 

Growth Estimates 

Increment cores were taken from 1,85' 4 sample trees 

well distribllted throughout the range of species and diameter ·classes encountered. The average 10-year diameter 

growth inside bark was computed by species and 2-inch 

d.b.h. class. A cur\re of diameter growth over average 

tree diameters was prepared and, from . bark thickness 

studies, an allowance was made for bark increase in the 

10-year period. This was added to the curve value of 

diameter growth indicated for each 2-inch d.b.h. class. The 

average volume of trees in the present 2-inch class was 

established and, from the growth curves, the future 10-

year volume of these present average trees was determined. 

The ratio of the present volume to the future volume was 

determined for each species and 2-inch diameter class. Onetenth of the volume growth in 10 years was used as the 

estimate of current annual gross growth. 

Ingrowth volume was estimated by plotting the number of trees over d.b.h. classes. The d.o.b. growth curves 

described above were used to determine the number of 

trees smaller than S' .0 inches d.b.h. expected to reach that 

diameter or larger in a 12-month period. The same type 

of estimate was made for trees expected to reach sawtimber size 11.0 inches d.b.h. The average volume of trees 

5 .1 and 11.1 inches in diameter was multiplied by the 

number of trees moving into the poletimber and sawtimber 

classes. 

Gross growth and ingrowth measurements were adjusted 

to net estimates on the basis of mortality data obtained 

from the field plots. 

Timber-Cut Estimates 

Estimates of timber cut in Iowa are based primarily 

upon a special study conducted by the Central States 

Forest Experiment Station in 195 4. This study included 

a sampling survey of wood-product producers and woodusers in Iowa. An area sample was used to determine the 

volume of timber cut for fuelwood, fence posts, and 

miscellaneous farm timbers. Data from the U. S. Department . of Commerce, Bureau of the Census, 195 4 

Census of Manufacturers also were used to develop lumber production estimates. 

Stump-measurements of trees cut within a 3-year period 

were taken in the course of the inventory field work. 

28 

When converted to volumes these stump records strength-

·ened break-down of timber-cut volume by species, diameter, .and geographic region. 

Complete canvasses of pulpwood and veneer-log using 

industries in the Central and Lake States since 195 4 

provided additional data on timber cut in Iowa. 

Accuracy of Estimates 

Statistical analysis of the Iowa forest area and timber 

volume data indicates sampling errors 1 as follows: 

Percent 

(plus or minus) 

1. Commercial forest area in the State 1.1 

2. Commercial forest area by 

geographic units ........... -...... .. 

3. Growing stock volume in the State ..... 

4. Growing stock volume by 

from 1. 5 to 3 .1 

3.6 

geographic units ........... -................. -.......... from 5.4 to 8.4 

5. Sawtimber volume in the State .............. 4.7 

6. Sawtimber volume by geographic units from 6.6 to 11 . 5 

1) At one standard deviation : That is, the chances are two out 

of three that the calculated acreages and volumes do not differ from the totals that would have been obtained by 100 

percent measurement by more than the percentages indicated. 

The estimates of sampling error do not include errors 

resulting from mistakes in measurement or judgment. All 

phases of field and office work were closely supervised 

to keep such errors to a minimum. 

Since the percentage error increases with each subdivision of the total, small acreages or volumes may have 

large errors; in some cases, therefore, these figures may 

indicate only relative magnitudes. The following tabulation indicates the reliability of subdivisions of forest areas 

and volumes in the tables of this report: 

Commercial Forest Growing Stock Sawtimber 

Sampling Sampling Sampling 

Area Error Volume Error Volume Error 

Thousand Million Million 

Acres Percent cu. ft. Percemt bd. ft. Percent 

2, 595 1,382 4 5,092 5 

1,000 2 500 6 1,000 11 

500 3 100 13 500 15 

100 6 50 19 100 34 

50 8 10 43 50 47 

10 18 13 5 10 106 

Timber-cutting estimates are obtained primarily by 

canvassing producers of primary timber products. These 

estimates are usually reported as either production items 

such as lumber or as receipts of roundwood such as veneer 

logs or pulpwood at wood-using plants. These data are 

mathematically converted to board-feet (International 

Y4-inch log rule) or cubic-foot volume after studies of 

mill over-run and woods residues have been made. 

Possible errors include reporting mistakes, errors in 

over-run and residue factors, and sampling errors. When 

data from several independent studies are combined, as 

was necessary in establishing a lumber production figure 

for Iowa, it is impossible to compute an exact sampling 

error. Every effort was made to develop the most reliable 

timber-cut estimates possible from the data available. The 
following tabulation shows the computed sampling error 

by commodity as found in the special timber-cut study 

made in 1954: 

Commodity 

Percentage 

of all timber cut from 

growing 

stock 

Pm-cent 

Sawlogs ·····-······································································· 54.4 

Fuel wood ............ ··············-····-···················· 3 3 .6 

Veneer logs ·······-······································ 3.8 

Cooperage bolts ··················································-····· 2.8 

Fence posts ...................................................................... 2.8 

Pulpwood ........................................................................ .9 

Miscellaneous ····--············································-··········· 1. 7 

Total .................................................................. 100.0 

EXPLANATION OF TERMS 

Forest Land 

Sampling 

Error 

Pm-cent ± 

13 

19 

1 

33 

1 

68 

12.3 

Includes (a) land which is at least 10 percent stocked 

by trees of any size and capable of producing timber or 

other wood products, or of exerting an influence on the 

climate or on the water regime; . (b) land from which 

the trees described in (a) have been removed to less than 

10 percent stocking and which has not been developed 

for other use; (c) afforested areas. 

The minimum area that qualifies as forest land is one 

acre. Strips of timber must be at least 120 feet wide to 

qualify. Conversely, clearings, streams, treeless strips and 

unimproved roads less than 1 'acre in area or less than 

120 feet wide within forest areas are classified as forest 

land. Improved rights-of-way, such as graded roads, railroads, or transmission lines, are classified as nonforest regardless of width. 

Commercial forest land.-Forest land which is (a) producing, or physically capable of producing, usable crops 

of wood (usually sawtimber), (b) economically available 

now or prospectively, and (c) not withdrawn from timber 

utilization. 

Noncommercial forest land.-Forest land withdrawn · 

from timber utilization through statute, ordinance, or 

administrative order but which otherwise qualifies as 

commercial forest land. 

Forest Type 

Oa~-hic~ory.-Forests in which 5'0 percent or more 

of the stand is upland oaks or hicl<ory, singly or in combination; except where bur oak makes up 5'0 percent or 

more of the stand (in which case the stand is classified 

"bur oak"); and except where redcedar makes up 25 percent or more of the stand (in which case the stand is classified "hardwood-redcedar ") . Common associates include 

elm, maple, and black walnut. 

Bur oa~. Forests in which 50 percent or more of the 

stand is bur oak. 

Hardwood-redcedar.-Forests in which 25 percent or 

more·of the stand is redcedar and the remainder is hardwoods, usually oaks. 

Northern hardwoods.-Forests in· which 50 percent or 

more of the stand is hard maple or yellow birch, singly or 

in combination. Common associates include elm and basswood. 

Elm-ash-cottonwood.-Forests in which 50 percent or 

more of the stand is elm, ash, or cottonwood, singly or in 

combination. Common associates include willow, sycamore, 

and maple. 

Aspewbirch.-Forests in which 50 percent or more of 

the stand is aspen, balsam poplar, or paper birch, singly 

or in combination. 

Tree Size and Condition 

Sawtimber trees.-Trees of commercial species that contain at least one merchantable sawlog as defined by regional practice and which are Of the following minimum 

diameters at breast height (d.b.h.): softwoods 9.0 inches 

and hardwoods 11.0 inches. 

Large sawtimber trees.-Hardwood and softwood sawtimber trees 15 .0 inches d.b.h. and larger. 

Small sawtimber trees.-Hardwood and softwood sawtimber trees less than 15 .0 inches d.b.h. 

Poletimber trees.-Trees of commercial species that 

meet regional specifications of soundness and form, and 

are of the following diameters at breast height: softwoods 

5.0 to 9.0 inches, hardwoods 5.0 to 11.0 inches. 

Seedling and sapling trees.-Live trees of commercial 

species less than 5 .0 inches in diameter at breast height, 

and of good form and vigor. 

Cull trees.-Live trees of sawtimber or poletimber size 

that are unmerchantable for sawlogs now or prospectively 

because of defect, rot, or species (such as sumac, redbud, 

hophornbeam). . 

Rotten cull trees.-Live trees of sawtimber or poletimber size that fail to meet regional specifications of 

proportion of sound volume to total volume. 

Sound cull trees.-Live trees of sawtimber or poletimber 

. size that meet regional specifications of freedom from rot 

but will not make at least one merchantable sawlog now 

or prospectively according to regional specifications because of roughness, poor form, or .species. 

Volr,;,me 

All-timber volume.-Net volume in cubic feet 'of live 

and salvable dead sawtimber trees and poletimber trees 

of commercial species, and cull trees of all species from 

stump to a minimum 4.0-inch top inside bark. Includes 

bole only of softwoods but both bole and limbs of hardwoods to a minimum 4.0-inch diameter inside bark. 

29 

. 
Live sawtimber vo!ume.-Net volume in board-feet, 

International Y4 -inch rule, of live sawtimber trees of 

commercial species to a merchantable top not less than 

8. 0 inches diameter inside bark for hardwood species and 

less than 6.0 inches d.i.b. for softwood species. 

Merchantable top.-The point on the bole of sawtimber 

trees above which a minimum merchantable sawlog, as 

defined regionally, cannot be produced. 

Growing oc ~ vo!ume.- N et volume in cubic feet of 

live sawtimber trees and live polctimber trees from stump 

to a minimum 4.0-inch top (of central stem) inside bark. 

Hardwood limbs.-Limbs of live hardwood sawtimber 

trees and sawtimber size cull hardwood trees to a minimum diameter of 4.0 inches inside bark. 

Upper stem portion.- N et volume in cubic fee t of 

bole of sawtimber trees betwee n merchantable top and 

a minimum top diameter of 4.0 inches inside bark on the 

central stem. 

Stocking 

Stocking is the extent to which growing space is effectively utilized by present or potenti al growing stock 

trees of commercial species. " Degree of stocking" is synonymous with " percent of growing space occupied" and 

means the ratio of actual stocking to full stocking for 

comparable sites and stands. 

W e!ht oc ~ed stands.- Stands that are 70 percent or 

more stocked with present or potenti al· growing stock 

trees. 

Medium -s oc ~ed stands.- Stands that are 40 to 69 percent stocked with present or potential growing-stock trees. 

Poorly c~ed stands.-Stands that are 10 to 39 percent stocked with present or potentia l growing-stock trees. 

oc ~ed area.-Areas that are 0 to 10 percent 

stocked with present or potential growing-stock trees. 

Site 

Forest Site.-Site class is determined by the average 

number of 16-foot merchantable logs that an area is 

ca pable of producing in mature trees. All stem sections 

Yz log (8 fee t) in length or longer, suitable for cross ties 

or ro ugh lumber were considered to be merchantable. 

Merchantable heights were estimated to the nearest Yz 

log. Where mature trees were not present, site was estimated from soil and moisture conditions, topography, 

exposure, and appearance of vegetation. The following 

site classes were recognized: 

Good.-Areas that can produce hardwood trees averaging 

three or more logs at maturity. 

Fair.- Areas that can produce hardwood trees averaging 

2 to 2Yz logs at matu rity. 

30 

Poor - Areas than can produce hardwood trees that average 1 to 1 Yz logs at maturity. 

Stand-size 

Sawtimber stands.- Stands with sawtimber trees having a minimum net volume per acre of 1, 500 board-feet, 

International Y4-inch rule. 

Large sawtimber stands.-Sawtimber stands having 

more than 50 percent of the board-foot volume in large 

sawtimber trees. 

Small sawtimber stands.- Sawtimber stands having 50 

percent or more of the net board-foot volume in small 

sa wtimber trees. 

Po!etimber stands.- Stands fa iling to meet the sawtimber stand specifications, but at least 10 percent stocked 

with poletimber and brger (5.0 inches d.b.h. and larger) 

trees and with at least half the minimum stocking in poletimber trees. 

Seedling and sapling stands.-Stands not qualifying as 

either sa wtimber or poleti mber stands, but at least 10 

percent stocked with trees of commercial species and 

with at least half the minimum stocking in seedling and 

sa piing trees. 

toc~ed and other areas not elsewhere classified.-

Areas not qualifying as sawtimber, poletimber, or seedling 

and sapling stands. 

Diameter 

Diameter at breast height (d.b.h.)-Tree diameter, outside bark, measured at 4. 5 feet above average ground level. 

Diameter class.-Trees were recorded in 2-inch diameter 

cl asses, each class including 1.0 inch below and 0.9 inch 

above the midpoint of the class; e.g. , the 8-inch class 

included all trees ranging from 7.0 to 8. 9 inches d.b.h. 

Diameter inside r~ (d.i.b,)- Tree di ameter inside 

the bark at any point specified. 

Hardwood log grade 

Grade l .- Butt logs at least 13.0 inches (u ppers at 

least 16 inches) in diameter inside bark with five-sixths 

of the surface on the three best faces clear of defect in 

not more than two cuttings, (minimum length of cutting 

variable, 3-7 feet, depending upon log diameter and position in tree. ) M inimum log length 10 feet. On the 

average such logs will yield at least 65 percent N o. 1 

common and better lumber. 

Grade 2.-Logs at least 11.0 inches in diameter inside 

bark with two-thirds of the surface on the three best 

faces clear of defect in not more than three cuttings, 

(minimum length of cutting, 3 feet) . Minimum log length 

8 feet. On the average such logs will yield at least 40 

percent N o. 1 common and better lumber. 
Grade 3.-Merchantable logs at least 8.0 inches in 

diameter inside bark at the small end, 8 feet long with 

one-half of the surface on the three best faces clear of 

defect in cuttings 2 feet long. Maximum cull deduction 

50 percent. On the average such logs will yield less than 

2 5 percent No. 1 common and better lumber. 

'fie and timber.-This class includes the roughest logs 

considered merchantable. Tie and timber logs must be 

at least 8.0 inches in diameter inside bark at the small 

end and at least 8 feet long. No limit is placed on surface 

defects as long as they do not extend into the interior 

enough to affect the strength of the contained tie or 

timber. 

Growth 

N,et annual growth of sawtimber.-The change during 

a specified year in net board-foot volume of live sawtimber on commercial forest land resulting from natural 

causes. 

N,et annual growth of growing stoc~.-The change 

during a specified year in net cubic-foot volume of growing stock on commercial forest land resulting from natural 

causes. 

Ingrowth.-The total volume of all trees that during 

• • 

the year reach the mm1mum diameter (5 .0 inches) for 

growing stock or the minimum diameter for sawtimber 

of 9.0 inches for softwoods and 11.0 for hardwoods. 

Mortality 

Annual timber mortality.-The net volume lost from 

live sawtimber or growing stock on commercial forest 

land during a specified year because of death from natural 

causes. 

Timber Cut 

Annual wt of live sawtimber.-The net board-foot volume of live sawtimber trees cut or killed by logging, and 

by land clearing and cultural operations, on commercial 

forest land during a specified year. 

Annual wt of growing stoc~.-The net cubic-foot 

volume of live sawtimber and poletimber trees cut or 

killed by logging, or by land clearing and cultural operations, on commercial forest land during a specified year. 

Logging residues from growing stoc~ -The net cubicfoot volume of live sawtimber and poletimber trees cut 

or killed by logging on commercial forest land and not 

converted to timber products . 

• 

Tree Species ' 

Softwoods 

Commercial species: 

Baldcypress ..................... . ......... 'f axodium distichum 

H emlock, eastern ...... . .. ............................. ........... 'Tsuga canadensis 

Pine: 

Eastern white pine 

Jack pine ...................... . ....................... .. 

................. Pinus strobus 

............................. P. b.an~ iana 

........... P. taeda 

..... P. rigida 

......... P. resin osa 

.............. P. echinata 

............... P. virginiana 

..... ]uniperus vlrginiana 

Loblolly pine .. .. 

Pitch pine ...... 

Red (Norway) pine 

Shortleaf pin e .................... .. 

Virginia pine ...... . 

Redcedar, eastern 

Hardwoods 

Commercial species: 

Ash: 

Blue ash .. 

Green ash 

White ash 

Aspen: 

........................... .......... Fraxinus quadrangulata ....................................... F. pennsylvani ca 

................... .F. americana 

Bigtooth aspen .............. Populus grandidentata 

Quakin g (tremblin g) aspen ........... . .................. P . tremuloides 

Basswood .... 'Tilia spp. 

Beech, american . .. ............ .Fagus grandifolia 

Birch ..... .. ............. Betula spp . 

Buckeye ....................... Aesculus spp. 

Butternut .......... ]u glans . ciner ea 

Catalpa .................. ....................... .. ................. Catalpa spp. 

Cherry, black ......... .. ..................... ........... Prunus serotina 

Cottonwood: 

Eastern cottonwood 

Swamp cottonwood .. 

.......... Populus delt oides 

......... P. heterophylla 

Cucumbertree .. ................................ . .......... Magnolia acuminata 

Dogwood .. 

Elm: .. ......................... Cornus spp . 

American elm ........ ..................................................... .. Ulm us americana 

Rock elm .............................. U. thomasii 

Slippery elm .. ........................ .. ..................................... U . rubra 

Win ged elm . . .............. .......... .. ............ U. alata 

Gum: 

Blackgum (black tupelo) .................................... N_yssa sylvatica 

Sweetgum (red) ................... . . ...... Liquidambar styraciflua 

Water tupelo (tupelo-gum) ...................... N_y ssa aquatic a 

Hackberry ....... .. ....... Celtis occidentalis 

Hickory ............. .. ........................... Carya spp. 

Hon eylocust ..... ... ........................................ .. ....... G leditsia triacanthos 

Kentucky coffeetree ............................. ......... G ymnocladus di oicus 

Locust, bl ack ........ .. .............................. . ............ R obinia pseudoacacia 

Maple, hard: 

Black maple .. 

Sugar maple . 

Maple, soft : 

Boxelder ........ . 

Red maple .. . 

Silver maple 

Mulberry, red 

Oak, red : 

Black oak ........ . 

Cherrybark oak 

..Acer nigrum 

.... A. saccharum 

.. ... A . negundo 

.. .............................................................. A . rubrum 

................... A . saccharinum 

....... Morus rubra 

..................... ........ rcus velutina 

(swamp red oak) ...... ~. falcata var. pagodaefolia 

Northern red oak .............. . rubra 

Pin oak . ...................... .. ...... . palustris 

Scarl et oak ............ ~. coccinea 

Shingle oak ........ .. ............................................. . imbricaria 

Southern red oak ..... ...................... .. .~ . falcata 

Water oak .......... .... .. ... . nigra 

Willow oak ................ ...................................................... · phellos 

31 
Oak, white : 

Bur oak 

Chestnut oak 

Chinkapin oak 

Overcup oak 

Post oak ................. . 

Walnut, black 

Willow 

Yellow-poplar 

N oncommercial species : 

Ailanthus (tree of heaven) 

H awthorn 

.................... . . ... Juglans nigra 

.. ................ .... ....................... Salix spp. 

......... .Liriodendron tulipifera 

..... Ailanthus altissima 

...... Crataegus spp . 

Swamp chestnut oak . 

Swamp white oak 

White oak 

..... Q.,. macrocarpa 

.................. ....... Q.,. prim.is 

............... Q.,. muehlenbergii 

...... Q.,. lyrata 

... Q.,. stellata 

.................. ......... ~. michauxii 

........... Q.,. bicolor 

... Q.,. alba 

...... Maclura pomif era 

. ..... .Diospyros virginiana 

...... Sassafras albidum 

........................ Pia tan us occidentalis 

H op hornbeam, eastern (ironwood) 

Pawpaw 

. ....... Ostrya virginiana 

.. ............. A simina triloba ........... Prunus spp . 

.......... Cercis canadensis 

......... Amelanchier spp . 

...... O x ydendrum arboreum 

.............. Rhus spp . 

Osage-oran ge 

Persimmon , common 

Sassa fras ...... . 

Sycamore, american 

Plum, wild 

Redbud , eastern 

Serviceberry 

Sourwood 

Sumac 

• • • 

Tables 

TABLE 1 - Total land and for e st area by geographic region and county, Iowa, 1954 

NORTHEASTERN SURVEY UNIT 

Allamakee 

Benton .. 

Buchanan 

Cedar 

Clayton 

Clinto n .. 

Delaware 

Dubuque. 

Fayette 

Iowa ••• 

County 

County 

Appanoose 

Boone 

Clarke 

Dallas 

Daris . 

Decatur , • 

Des Moines. , 

Guthrie •. 

Henry •. 

Jefferson 

Keokuk. 

Lee ••• 

Louisa. 

To'tal land 

area !.f Forest area 

Thousand Thousand Perc e nt 

acre s 

409 

460 

364 

374 

498 

445 

367 

389 

466 

374 

acres 

132 

20 

17 

23 

120 

30 

27 

56 

38 

30 

32 

4 

5 

6 

24 

7 

7 

14 

8 

8 

Jackson 

Johnson 

Jones 

C o unty 

Linn •• 

Muscatine. 

Poweshiek 

Scott ••.• 

Toma .••. 

Winneshiek 

Total . 

SOUTHEASTERN SURVEY UNIT 

To t al land 

are a .!J 

Thousand 

acre s 

335 

367 

275 

382 

326 

339 

262 

381 

282 

279 

371 

334 

258 

F o rest area 

Thou sand Perc ent 

acres 

56 

30 

39 

36 

51 

57 

40 

38 

36 

37 

35 

81 

41 

17 

8 

14 

9 

16 

17 

15 

10 

13 

13 

9 

24 

16 

C o unty 

Luc as • .•. 

Madison .•• 

Mahaska . . 

Marion • 

Monroe • • • 

Polk . . .. 

Ringgold . • 

Van Buren .• 

Wapello •. 

Warren •• , 

Washington 

Wayne •.. 

Webster •. 

Total . 

!_! Source: Areas of the United States, 1950, U. S. Bure a u o f the Census. 

Does not include a reas listed as inland water. 

32 

Total land 

ar e a .!J 

Thou s and 

a c res 

412 

397 

374 

456 

281 

377 

290 

461 

440 

7,634 

Total land 

are a _!_ ! 

Thou s and 

a c res 

278 

362 

366 

363 

278 

380 

344 

3 12 

280 

366 

363 

340 

459 

8,682 

F o re s t area 

Th o usand Percent 

a c r es 

82 20 

41 10 

42 11 

46 10 

30 11 

17 5 

15 5 

30 7 

56 13 

852 11 

F o rest a rea 

Thousand Perc e nt 

a cre s 

51 18 

50 14 

31 8 

52 14 

71 26 

32 8 

27 8 

64 21 

49 18 

44 12 

37 10 

27 8 

26 6 

1, 138 13 
WESTERN SURVEY UNIT 

Total !and Total land County area .!_/ Fore st area County area_!_ / Fore st area 

Thousand Thousand Thousand Thousand acres acres Percent acres acres Percent 

Adair •.•••.• ....... 364 12 3 Humboldt . .... 278 6 2 

Adams •.•••• ....... 273 16 6 Ida • ..... 0 276 2 1 

Audubon ••••• 287 4 1 Jasper •• 471 31 7 

Black Hawk •• 363 17 5 Kossuth . 627 8 1 

Bremer •••• 281 15 5 Lyon • •• 376 4 1 

Buena Vista 367 5 1 Marshall . 367 14 4 

Butler ..... 373 15 4 Mills . .. 285 25 9 

Calhoun •• • • 366 2 1 Mitchell ...... 299 10 3 

Carroll ••••• 367 5 1 Monona •••••. 446 48 11 

Cass .•••.• 358 9 3 Montgomery .• • 270 10 4 

Cerro Gordo •• 369 4 1 O'Brien .. 368 4 1 

Cherokee .. 367 11 3 Osceola . . .. 255 2 8 

Chickasaw ...... 323 16 5 Page • .•..•..••••.. 342 12 4 

Clay ..... . ..... 365 8 2 Palo Alto .•••• • •• u ... 359 6 2 

Crawford .• 458 14 3 Plymouth •• 0 ••••• 552 12 2 

Dickinson. 244 4 2 Pocahontas •• , ••• 371 1 v Emmet .•• 253 4 2 Pottawattamie 617 27 4 

Floyd •••• ....... 322 9 3 Sac ••••.. 370 6 2 

Franklin •• 375 4 1 Shelby . ...... 376 5 1 

Fremont .• 335 31 9 Sioux •.•• • •• 490 3 1 

Greene ••••• 364 12 3 Story •.••..• 364 13 4 

Grundy ••••• 321 1 v Taylor ••••• 338 21 6 

Hamilton •••• 369 9 2 Union •• •• • 273 22 8 

Hancock ••.. 365 3 1 Winnebago .• 257 3 1 

Hardin ••. 367 14 4 Woodbury 558 25 4 

Harrison. 445 44 10 Worth •• . 257 5 2 

Howard ••. 301 11 4 Wright . . 369 6 2 

Total • . .•••• . ••• 19,553 630 3 

'!:__ / Less than 0.5 percent. 

TABLE 2 - land area by major use and physiographic region, Iowa, 1954 

Land use Total Northeast Southeast Western 

Thousand Percent Thousand Percent Thousand Percent Thousand Percent 

acres acres acres acres 

Forest: 

Commercial 2,595 7.2 846 11.1 1, 127 13. 0 622 3.2 

Noncommercial: 

Withdrawn from 

timber use . .. . . .; 25 • 1 6 .1 11 • 1 .. 8 l_/ 

Nonproductive 

Total forest 

land 2,620 7.3 852 11.2 1, 138 13.1 630 3. 2 

Nonforest • .• 33,249 • 92. 7 6,782 88.8 7,544 86.9 18,923 96. 8 

Total land area ........ 35,869 100.0 7,634 100.0 8,682 100.0 19,553 100.0 

1_/ Less than 0.05 percent 

33 
TABLE 3 - Commercial forest area by ownership and geographic region, Iowa, 1954 

Ownership class Total Northeastern Southeastern 

Thousand acres Percent Thousand acres Thousand acres 

Federal: 

National forest 2.7 0.1 2.7 

Indian ••••••• 1.0 l./ 1.0 

Other . . ..... 9.2 .4 7.6 1.6 

Total. 12.9 0.5 8.6 4.3 

State ••••••••••• 22.0 0.9 7.2 12.8 

County and municipal ... 1. 9 .1 .6 .5 

Private: 

Farm ••••••••••• 2,282.1 87. 9 764.0 965. 1 

Industrial and other • 276.1 10.6 65.6 144.3 

Total •••••.. 2,558.2 98.5 829.6 1, 109.4 

All own~rships ••• • 2,595.0 100.0 846.0 1,127.0 

. !) Less than 0.05 percent 

TABLE 4 - Commercial forest area by stand-size and geographic region, Iowa , 1954 

Stand-size class Total Northeastern Southeastern 

We stern 

Thousand acres 

2.0 

.8 

553.0 

66.2 

619.2 

622.0 

We stern 

Thousand Thousand Thousand Thousand 

acres Percent acres Percent acres Percent acres Percent 

Large sawtimber stands •. 738 28.4 309 36.5 224 19.9 205 33.0 

Small sawtimber stands 268 10.3 133 15.7 99 8.8 36 5.8 

Poletimber stands •••• 830 32.0 248 29.3 396 35.1 186 29.9 

Seedling and sapling 

stands ••••..•••••• 287 11.1 44 5.2 192 17.0 51 8.2 

Nonstocked and other 

areas .. . . . . . . . . . . 472 18.2 112 13. 3 216 19.2 144 23.1 

Total 2,595 100.0 846 100.0 1,127 100. 0 622 100.0 

TABLE 5 - Commer c'ial forest area by forest type and geographic re gion, Iowa, 1954 

Forest type Total Northeastern Southeastern Western 

Thousand Thousand Thousand Thousand 

acres Percent acres Percent acres Percent acre s Percent 

Oak· hickory ••••••. 1,036 39.9 364 43.0 567 50.3 105 16.9 

Northern hardwoods ••• 78 3.0 66 7.8 5 .5 7 1.1 

Elm· as·h ·cottonwood ... 1,219 47.0 346 40.9 503 44.6 370 59.5 

Aspen - birch ••••••• _. • 20 .8 15 1.8 5 .8 

Bur oak ............ 202 7.8 36 4.3 37 3.3 129 20.7 

Hardwood· redcedar .... 40 1.5 19 2.2 15 1.3 6 1.0 

Total ............ 2,595 100.0 846 100.0 1,127 100.0 622 100.0 

TABLE 6 - Commercial forest area by forest type and stand-siz e class, Iowa, 1954, (in thousand acres) 

Large Small Pole· Seedling N o nstocked Forest type Total sawtimber sawtimber timber & sapling and other stands stands stands s t ands areas 

Oak - hickory ..•••• 1,036 220 131 385 140 160 

Northern hardwoods .• 78 44 19 10 5 

Elm· ash· cottonwood 1,219 44 4 100 323 120 232 

Aspen- birch ••••.•••• 20 5 10 5 

Bur oak .......... 202 30 13 78 16 65 

Hardwood- red cedar • • ~ 40 24 11 5 

Total .......... 2,595 738 268 830 287 472 

Percent •.••••••• 100.0 28.4 10.3 32.0 11.1 18.2 

34 
TABLE 7 - Comme rc ial forest area by physiographic site and stand-size class, Iowa, 1954 

Large Small Pole- Seedling Nonstocked 

Physiographic site Total sawtimber sawtimber t im ber & sapling and other stands sta:nd s areas 

Thou san d Thou sand Thousand Thousand Thousand Thousand 

acres Percent acres acres acres acres acres 

Level upland . 343 13.2 96 41 107 35 64 

Rough upland. 1, 587 61.2 371 160 584 179 293 

Bottoroland 665 25. 6 271 67 139 73 115 

Total .. 2,595 100.0 738 268 830 287 472 

TABLE 8 - Net board-foot vo lume on commercial forest area by ownership and geographic region, Iowa, 1954 

Ownership State to ta! Northeastern Southeast ern 

Million Million Mill ion 

bd. ft. Percent bd. ft. bd. ft. 

Public: 

National forest 4 0.1 4 

Indian ••••• •• 3 .1 3 

Other Federal .. 21 .4 19 2 

State •.• • . •.• 40 . 7 18 18 

County and Municipal • 3 . 1 1 1 

Total public ... 71 1.4 41 25 

Private: 

Farro .... . .. .. 4,5 15 88.7 1,932 1,391 

Industrial and other 506 9.9 167 208 

Total private •• 5,021 98.6 2,099 1,599 

All ownerships 5,092 100.0 2, 140 1,624 

TABLE 9 - Net board-fqot volume o n commercial forest area by species and geographic region, Iowa, 1954 

North- South- Species Total easte rn easte rn 

Million Million Mill ion 

bd. ft. Percent bd. ft. bd. ft. 

Eastern redcedar 6 0.1 3 3 

Black ash ... 39 .8 28 

American elm . 742 14.6 252 285 

Slippery elm 330 6.5 144 92 

Aspen • u •• 15 .3 15 

Cottonwood. 601 11.8 166 116 

Basswood •• 342 6. 7 181 83 

Silver maple 462 9.1 145 174 

Sycamore .. 9 .2 9 

Boxelder .•• 23 .4 11 3 

Butternut .. 23 .4 22 1 

Black cherry 23 .4 18 3 

Hackberry •• 29 .6 8 5 

Willow • • •• 130 2.6 42 63 

Other soft hardwoods. 11 .2 1 6 

White oak • .••. 504 9. 9 219 247 

Bur oak ..... . 360 7.1 79 126 

Other white oaks 23 .4· 11 9 

Black oak •• •.. 96 1. 9 75 21 

Northern red oak •• 532 10.4 290 185 

Other red oaks •• . 135 2.7 96 22 

Hickory ... 155 3.0 79 46 

White ash . • 161 3.2 68 33 

Sugar maple • 98 1.9 71 13 

River birch . 37 . 7 16 14 

Black walnut . 193 3.8 86 67 

Other hard hardwoods 13 .3 5 7 

Total ... .. .. .. 5,092 100.0 2,140 1,624 

Western 

Mi11 ion 

bd. ft. 

4 

1 

5 

1, 192 

131 

1,323 

1,328 

Western 

Million 

bd. ft . 

11 

205 

94 

319 

78 

143 

9 

2 

16 

25 

4 

38 

155 

3 

57 

17 

30 

60 

14 

7 

40 

1 

1,328 

35 
TABLE IO - Net board-foot volume on commercial forest area by forest type and geographic region, Iowa, 1954 

F o rest type Total 

Million 

bd. ft. Percent 

Oak - hickory •• • ••• l, 701 33.4 

Northern hardwoods •. 303 5.9 

E lm - ash- cottonwood 2,838 55.7 

Aspe n - birch ••• • • • 14 .3 

Bur oak ......... 227 4.5 

Hardwood- red cedar. 9 .2 

Total ... ..... 5,092 100.0 

Northeastern 

Mill ion 

bd. ft. 

863 

236 

979 

14 

41 

7 

2, 140 

S o utheastern 

Million 

bd, ft. 

705 

41 

816 

60 

2 

1,624 

Western 

Miliion 

bd. ft. 

133 

26 

1,043 

126 

1,328 

TABLE 11 - Net board-foot volume on commercial forest area by physiographic site and stand-size class, Iowa , 1954 

Large Small Pole- Seedling Non stocked 

Physiographic site T o tal s awtimbe r sawtimber timber & sapling and other 

stands stands st and s stands are as 

Miliion Millio n Mill ion MilI ion Mi lI ion Mi li io n 

bd. ft. Percent bd. ft. bd. ft. bd. ft. bd, ft . bd. ft. 

Level upland ••••• 743 14.6 496 161 68 5 13 

Rough upland, 2, 492 48. 9 1,441 521 329 58 143 

Bottomland 1,857 36.5 1,414 223 101 55 64 

Total .. 5,092 100.0 3,351 905 498 11 8 220 

TABLE 12 - Average board-foot vo lume per acre by physiographic site and stand-size class, Iowa, 1954 

Large Small Pole- Seedling Nonstocked Physiog raphic site Total sawtimb e r sawtimber timber & sapling and other stands stands stands stands areas 

Level upland .•••• 2,166 5, 167 3,927 636 143 203 

Rough upland. 1,570 3,884 3,256 563 324 488 

Bottomland 2, 792 5,218 3,328 727 753 557 

Total .. 1,962 4,541 3,377 600 411 466 

TABLE 13 - Net board-foot volume on commercial forest area by tree-diameter class and geographic region, Iowa, 1954 

Tree·diameter class (inc h es) T o tal 

Mill ion 

bd. ft. P ercent 

12- 14 

16- 18 

20 - 22 

24 - 26 

28+ • . 

Total 

!_! ••. 1,540 

1,501 

927 

476 

648 

5,092 

.!..! Includes 10" softwood sawtimber 

36 

30.2 

29.5 

18.2 

9.4 

12.7 

100.0 

N ortheastern 

Million 

bd. ft. P erce n t 

717 33.5 

649 30.3 

351 16.4 

173 8.1 

250 11. 7 

2, 140 100.0 

Southeastern Western 

Million Million 

bd, ft. Percent bd. ft. Percent 

526 32.4 297 22.4 

482 29.7 370 27.9 

270 16.6 306 23.0 

162 10.0 141 10.6 

184 11. 3 214 16.1 

1,624 100.0 1,328 100.0 
TABLE 14 - Net board-foot volume on commercial forest area by species and stand-size class, Iowa, 1954 

Species Large Smell Pole· Seedling T ot al sawtimber sawtimb er timber & sapling stands stands stands stands 

Million Million Million Million Mi/Hon bd. ft. P ercent bd. ft. bd. ft. bd. if. bd. It. 

Eastern redcedar ..... 6 0. 1 1 2 2 

Black ash •• • .... .. 39 .8 34 4 1 

American elm. ..... . 742 14.6 469 92 99 18 

Slippery elm ...... 330 6.5 239 so 29 4 

Aspen •• 0 • • 15 .3 1 14 

Cottonwood . 601 11.8 527 48 19 

Basswood •• 342 6.7 256 37 25 4 

Silver maple 462 9.1 375 73 12 2 Sycamore •• 9 .2 9 

Boxelder •. • 23 .4 11 3 5 3 

Butternut .. 23 .4 15 6 1 1 

Black cherry •• ••• •. 23 .4 10 5 4 4 

Hackberry •••.•••.• 29 . 6 24 4 1 

Willow ••••• • ••••• 130 2.6 36 31 34 22 

Other soft hardwoods •••• 11 .2 8 2 1 

White oak .•••••• 504 9.9 253 141 66 30 

Bur oak ........ 360 7.1 196 65 59 2 

Other white oaks 23 .4 16 6 1 

Black oak • •••• 96 1.9 33 49 6 8 

Northern red oak •• 532 10. 4 378 108 38 

Other red oaks • ••• 135 2. 7 73 27 17 

Hickory 155 3.0 52 48 39 11 

White ash • .• •••• 161 3.2 11 6 21 2 11 

Sugar maple •••••• 98 1.9 85 9 1 

River birch • •• ••• 37 .7 33 1 3 

Black walnut ••••• 193 3.8 100 61 23 6 

Other hard hardwoods 13 .3 2 9 1 

Total .. . . . . . . 5,092 3,351 906 497 118 

Percent. . . .. ... . 100.0 65. 8 17.8 9.8 2.3 

l / Less than 0. 5 million board· feet 

TABLE 15 - Net board-feet vo lume on commercial forest area by s pecies and tree-diameter class, Iowa, 

On million board-feet) 

Species T otal 

12. 14 

Ea stern re dcedar . ... 6 u 6 

Black ash • • • . . . . . . 39 11 

American elm. 742 182 

Slippery elm • •• •• • 0 330 103 

Aspen . . .. . . ....... 15 11 

Cottonwood • • . . . . . . . 601 53 

Basswood • •• . . . . . . 342 99 

Silver maple 462 86 

Sycamore . . . 9 

Boxelder ••.• 23 15 

Butternut ... 23 11 

Black cherry • 23 17 

Hackberry ... . . . . . . 29 9 

Willow • • • •• . . . . . . 130 75 

Other soft hardwoods •• 11 6 

White oak ••••• • ••••• 504 198 

Bur oak ... ....... . . 360 137 

Other white oaks 23 7 

Black oak, •• • • ••.••• 96 33 

Northern red oak • .• 532 147 

Other red oaks •• • • 135 51 

Hickory .. . 155 108 

White ash • . • 16 1 46 

Sugar maple •• 98 35 

River birch. 37 6 

Black walnut • 193 85 

Other hard hardwoods . .. 13 3 

Total ... • ••• • 5,092 1.1 1,540 

Percent •• 100.0 30.2 

!./ Includes 10-inch softwood sawtimber 

16 . 18 

21 

228 

113 

4 

85 

135 

124 

6 

10 

6 

7 

38 

5 

166 

106 

7 

33 

174 

31 

43 

34 

26 

13 

76 

10 

1,501 

29.S 

Tree-diameter c lass (inches) 

20 . 22 24 . 26 

7 

158 83 

61 14 

89 110 

76 15 

142 6 1 

2 

2 

2 4 

5 12 

85 24 

56 37 

2 

18 

124 54 

22 23 

4 

26 8 

18 9 

7 11 

23 9 

927 476 

18.2 9.4 

28. 30 

30 

39 

95 

7 

24 

9 

7 

24 

19 

7 

12 

16 

47 

10 

346 

6.8 

Nonstocked 

and other areas 

Mill ion 

bd. ft. 

1 

64 

8 

7 

20 

l! 

1 

7 

14 

38 

8 

18 

16 

11 

3 

3 

1 

220 

4.3 

1954 

32 + 

61 

169 

10 

25 

7 

5 

17 

8 

302 

5.9 

37 
TABLE 16 - Net board-foot volume on commercial forest land by species and forest type, Iowa, 1954 

On million board-fe et) 

Species Total Fore st types 

ElmOak - Northern ash - Asp en - HardwoodHickory hardwoods cottonwood birch Bur oak re deed ar 

Eastern redcedar 6 1 5 

Black ash •. . 39 2 8 29 

American elm. 742 116 4 611 9 2 

Slippery elm 330 60 23 244 3 

Aspen .. . . 15 8 1 6 

Cottonwood . 601 2 594 5 

Basswood •• 342 61 119 160 2 

Silver maple 462 462 

Sycamore 9 9 

Boxelder .•.. 23 1 22 

Butternut .. 23 5 11 7 

Black cherry . 23 9 13 

Hackberry •.• 29 5 24 

Willow •... . 130 130 

Other soft hardwoods~ 11 4 6 1 

White oak .. . .. 504 480 5 16 2 

Bur oak . ....... . 360 107 1 81 171 

Other white oaks 23 5 18 11 

Black oak . • ••. 96 80 5 11 

Northern red oak. 532 437 51 37 7 

Other red oaks . 135 77 8 38 2 10 

Hickory . " ..... 155 122 5 22 4 2 

White ash ..•• . . 161 20 4 136 1 

Sugar maple ..•.. . . 98 27 56 15 

River birch . .....• 37 2 35 

Black walnut .•..•. 193 74 3 111 5 

Other hard hardwoods 13 13 

Total .. 5,092 1, 701 303 2,838 14 227 9 

Percent • 100.0 33.4 5.9 55. 7 3 4.5 0.2 

u Less than 0. 5 million board-feet 

TABLE 17 - Hardwood s awtimber volume by log grades and geographic regions, Iowa , 1954 

Region Total Log grade Log grade 2 Log grade 3 Tie & Timber grade 

Mill ion Million Million Mi Ilion Million 

bd. ft. bd. ft. Per cent bd. ft. Percent bd. ft. Perc e nt bd, ft. Percent 

Northeastern 2, 137 181 8 339 16 849 40 768 36 

Southeastern 1,621 172 10 302 19 498 31 649 40 

Western 1,328 231 17 340 26 378 28 379 29 

State •• 5,086 584 12 981 19 1, 725 34 1, 796 35 

TABLE 18 - Hardwood s awtimber volume by log grade s and tree diameter class, Iowa, 1954 

Tree diameter class Log grade 

Million Mil lion 

Inches bd. It, Percent bd. ft. 

12- 14 1,534 30 9 

16-18 1,501 30 139 

20+ ... 2,051 40 436 

Total 5,086 100 584 

38 

Log grade 2 

Million 

bd. ft. 

99 

366 

516 

981 

Log grade 

Million 

bd, It. 

598 

476 

651 

1, 725 

3 Tie and Timber 

Million 

bd. It. 

828 

520 

448 

1, 796 
TABLE 19 - Hardwood sawtimber volume by species group and log grade, Iowa, 1954 

Species group Total Log grade 1 Log grade 2 Log grade 3 Tie and 

timber 

grade 

Million Million Million Million Million 

board- board- board.• board- boardfeet feet Percent feet Percent feet Percent feet Percent 

American elm ••.•• 1,072 147 14 214 20 414 38 297 28 

Cottonwood •.••• • 601 172 29 118 19 167 28 144 24 

Silver maple 462 44 9 74 16 156 34 188 41 

White oaks 1/ ...... .. 527 27 5 116 22 159 30 225 43 

Bur oak ••• 0. 360 78 22 51 14 231 64 

Red oaks .......... 763 25 3 86 11 289 38 363 48 

Hickory ........ 155 8 5 75 49 72 46 

Black walnut ••. 193 32 17 53 27 97 50 11 6 

Other hardwoods. 953 137 14 234 25 317 33 265 28 

Total . ...... 5,086 584 12 981 19 l, 725 34 1, 796 35 

.!./ Includes all white oaks except bur oak 

TABLE 20-Net cubic-foot volume of growing stock on commercial forest area by species and geographic region, Iowa, 1954 

Species Total Northeastern Southeastern 

Million 

cu. ft. Percent Million cu. ft. Million cu. ft. 

Eastern redcedar 3.8 0.3 2.1 1.4 

Black ash ..• 11.4 .8 7.9 

American elm 206.6 15.0 70.1 83.5 

Slippery elm 88.2 6.4 34.8 30.6 

Aspen ..... 15.0 1.1 14.8 .2 

Cottonwood . 120.4 8.7 32.0 22.8 

Basswood .• 83.0 6.0 46.5 18.6 

Silver maple 113.9 8.2 33.4 48.5 

Sycamore .. 1. 7 .1 1. 7 

Hackberry •• 9.9 .7 2.2 3.4 

Willow .... . 61. 9 4.5 11.7 34.9 

Other soft hardwoods •.•. 25.6 1.9 16.5 5.0 

White oak •..••..•••• '132. 5 9.6 57.2 63.8 

Other white oaks .. 112.2 8.1 27. 7 37.3 

Northern red oak •• . 126.8 9.2 69.2 41.3 

Other red oaks • 65.6 4.7 42.2 17.5 

Hickory ..... ... 63.6 4.6 27.9 24.6 

White ash •. •• ••. 45.5 3.3 18. 2 9.7 

Sugar maple ..•••• 24.9 1.8 18. 2 3.7 

Black walnut .••.• 52.8 3.8 22.9 19.5 

Other hard hardwoods 16.7 1. 2 7.2 7.0 

Total ... • 1,382.0 100.0 564.4 473.3 

Percent •• 100.0 40.8 34.3 

TABLE 21 - Net cubic-foot of growin£5 stock on commercial forest area by 

stand-size class and tree-diameter class, Iowa, 1954 

On million cubic feet) 

Tree-diameter class (inches) 

Stand .. size class Total 6 8 10 12 14 16 

Large sawtimber 

stands .... ... 754.1 9.2 20.2 51.0 58.8 65.6 104. 7 

Small sawtimber 

stands • 0 •••• • 267.3 5.3 19.2 49.0 65.0 65.4 29.1 

Pole timber 

stands ... ". 271.1 38.8 54.6 66.4 33.5 29.5 16.1 

Seedling and 

sapling stands 32.0 2.5 2.2 1.4 3.0 6.6 4.1 

Nonstocked and 

other areas •• 57.5 1.5 2.9 4.0 6. 7 9.4 10.2 

Total ... 1,382.0 57.3 99.1 171.8 167.0 176.5 164.2 

Percent •• 100.0 4.1 7.2 12.4 12. 1 12.8 11. 9 

Western 

Million cu. ft. 

0.3 

3.5 

53.0 

22.8 

65.6 

17.9 

32.0 

4.3 

15.3 

4.1 

11. 5 

47.2 

16.3 

5.9 

11.1 

17.6 

3.0 

10.4 

2.5 

344.3 

24.9 

18 20+ 

103.9 340. 7 

19.3 15.0 

11.6 20.6 

3.4 8.8 

3.4 19.4 

141.6 404.5 

10.2 29.3 

39 
TABLE 22 - Net cubic-foot volume of grawing stock on commer cial for est area by 

spec ies and tr ee-diameter class, Iowa, 1954 

On million cubi c feet) 

Species Total 6 8 10 12 14 16 18 20+ 

inche s inches inches inches inches inches inches inches 

Eastern redcedar· ••• •• • 3.8 0.7 1.9 0.3 0.5 0.4 

Black ash •.•••••• •• • 11.4 .2 . 6 2.8 1.1 1.5 2.0 1. 8 1.4 

American elm •• • •••• • • 206.6 8.8 12.3 25.0 20.3 22.5 26.9 2 1.0 69.8 

Slippery elm ........ . 88.2 4.0 7.3 9.6 11.1 11.4 8.6 14 . 1 22.1 

Aspen • • • •• • ••••• 0 . 15.0 1.2 2.7 7.8 2.0 .5 .8 

Cottonwood ••• . . . . . . . 120.4 .8 1.4 2.7 4.1 7.0 9.9 7.0 87.5 

Basswood .••••.••• • • 83.0 1. 7 5. 1 5.6 9.2 12.2 14.5 13. 5 21.2 

Silver maple .. .. ... .. 113.9 2.1 4 . 7 15.0 9.7 9.3 12.2 12.6 48.3 

Sycamore .. " ...... .. 1. 7 1/ 1. 7 

Hackberry •• • .••••• • . 9.9 1.0 1. 7 1.3 1.1 .9 . 8 . 6 2.5 

Willow • •• ••• • ••.• •• 61. 9 2.3 10.4 18.4 9.4 9.6 3.7 4.6 3.5 

Other soft hardwoods •• • • 25.6 1.8 2.6 3.5 5.6 5.0 3. 6 2.7 .8 

White oak • .••••••• • • 132.5 6.3 8.6 16.6 18.6 23.0 16.8 15.3 27.3 

Other white oaks .... .. 112.2 5.5 8. 2 15.2 17.4 15.6 14.6 10.0 25.7 

Northern red oak .••.• • • 126.8 3.0 5.2 9. 8 16. 7 16.4 16. 0 18.6 41.1 

Other red oa ks •••••• • • 65 .. 6 3.9 5.3 7.5 7.5 11.4 7.8 5.3 16.9 

Hickory .... .. . .... . . 63.6 8.3 8. 9 14.6 13.4 9.6 6.9 1.1 . 8 

White ash •• • • ••••• • . 45.5 1. 3 4 .8 5.5 4.9 5.5 4.2 2.7 16.6 

Sugar maple ••.••••• • • 24.9 1.0 1. 7 2.1 3.9 3.7 2.1 3.1 7.3 

Black wl'lnut ••••••. • • 52.8 1. 7 3.7 6.1 9.3 10.1 11.2 4 .3 6.4 

Other hard hardwoods .. . 16. 7 1. 7 2. 0 2.4 1.2 .9 1. 6 3.3 3.6 

Total .... ....... . . 1,382.0 57.3 99. 1 171. 8 167.0 176.5 164.2 141. 6 404.5 

Percent ••••••••••• 100.0 4.1 7.2 12.4 12. 1 12 . 8 11.9 10.2 29.3 

1/ Less than 0.05 million cubic feet 

TABLE 23 - Net cubic-foot volume of growing stock on commercial forest area by s pecies and for est typ e, Iowa, 1954 

(In million cubi c feet) 

Species T o tal Elm· 

Oak North e rn ash- A sp en- Hardwood -

hickory hardwood' cottonwood birch Bur oak redcedar 

Eastern redcedar . . ... .. 3.8 0.5 0.3 3.0 

Black ash •••••• • ••• • 11.4 1.0 1.5 8. 6 0.3 

American elm ..• • • •.•. 206.6 33.9 1.5 167.3 0.1 3.1 . 7 

Slippery elm ........ . 88.2 15.7 5.7 64 .6 . 1 2.1 

Aspen ............. 15.0 4.7 .7 .3 9.3 

Cottonwood • •.•••••.• 120.4 .4 119. 0 1.0 

Basswood •••• •• •••. • 83.0 16.6 29.0 37.0 .4 

Silver maple ......... 113.9 113.9 

Sycamore .... ..... ... 1. 7 1. 7 

Hackberry •• • • • • • ••.• 9.9 2.3 7.5 . 1 

Willow •• ••. • ••• •• •. 6 1. 9 61.9 

Other soft hardwoods • ••• 25.6 7.2 3.6 13.8 .4 .6 

White oak . .......... 132. 5 125.1 1.6 4.3 1.2 .3 

Other white oaks ...... 112.2 34.6 . 4 24.3 52.9 

Northern red oak •. ..... 126.8 103.1 10.4 9.5 1. 7 2. 1 

Other red oaks •••• .. • . 65.6 45.7 1.5 11. 8 . 4 6.2 

Hickory ..... ... ... u .. 63.6 50.4 1. 2 9.9 • 2 1.3 .6 

White ash .. .. ...... . 45.5 5.6 .9 38. 7 • 1 "2 

Sugar maple • • •• ••• ••• 24.9 7. 6 13.3 3.8 .2 

Black walnut • •••.. ••• 52. 8 21.6 .6 29. 3 1.1 .2 

Other hard hardwoods ". 16. 7 1.0 15. 7 

Total ..... . .. ..... 1,3 82.0 477.0 71.9 743.2 14. 8 70.8 4.3 

Percent • . . . . . . . . . . 100.0 34.5 5.2 53.8 1.1 5. 1 0.3 

40 
TABLE 24 - Net cubic-foot volume of grawing stock on commercial forest area by species and stand-size class, Iowa 1954 

(In mi llion cubi c fee t) ' 

Large Small P ole- Seedling Nonstocked 

Species Total sawtimber sawtimb er timber & sapling and other 

stands stands stan ds stan ds areas 

Percent 

Eastern redcedar 3 . 8 0. 3 l_/ 0.3 2. 3 0.9 0. 3 

Black ash •.•• • : : : : : : 11.4 .8 9.2 1. 5 .4 . 3 

American elm .••. •• ••• 206. 6 15.0 113. 7 27. 8 44. 2 4.2 16. 7 

Slippery elm .. . .. ... . 88.2 6.4 52.9 13 . 2 18. 2 1. 6 2.3 

Aspen • DD D 0 DD DD e 0 0 D 15.0 1.1 1. 7 9. 0 4.3 

Cottonwood ••••••••• . 120.4 8. 7 100.6 13. 7 3. 9 . 7 1.5 

Basswood •• 83.0 6. 0 58. 9 10.2 8.7 1.0 4 . 2 

Silver maple ...... ... 11 3. 9 8.2 82. 8 23.3 7.1 . 6 .1 

Sycamore • • • 0 . .. .. .. . 1. 7 .1 1. 7 

Hackberry • .• • . •• ••• . 9. 9 .7 6. 3 1. 2 2.2 . 2 

Willow .... ... ..... 6 1. 9 4 . 5 12. 0 10.4 3 1. 9 5. 2 2.4 

Ot her soft hardwoods •.• . 25.6 1.9 11. 3 6. 2 5.2 2. 2 . 7 

White oak ••••• •. ••• • 132. 5 9.6 55.0 36.0 31.0 6. 8 3.7 

Other white oaks . .. .. . 112. 2 8. 1 48. 9 21.6 31.3 1.0 9.4 

Northern red oak •••• • • • 126. 8 9. 2 78. 0 30.3 16.6 . 1 1.8 

Other red oaks ...• ..•. 65.6 4.7 23.2 18. 9 17.2 2.0 4.3 

Hickory ....... ... ... 63.6 4.6 17. 5 15. 2 25. 1 1. 2 4. 6 

White ash • .• • .... . . . . 45. 5 3.3 28. 7 8.4 3.4 2. 6 2.4 

Sugar mapl e .. 0 0 0 DD D 0 24. 9 1.8 19.1 4 . 2 .9 . 7 

Black walnut • •• . .•••. 52.8 3. 8 23 . 6 15.4 11. 1 1. 7 1. 0 

Other hard hardwoods ... 16. 7 1.2 9.0 . 5 6.1 .2 .9 

Total ...... .... .. 1,382.0 754.1 267.3 27 1. 1 32.0 57.5 

Perce nt ••••••• .• •• 100.0 54. 6 19.3 19.6 2.3 4 . 2 

!._! Less than 0.05 million cubic feet 

TABLE 25 - Total cubic volume of sound material on commercial forest area by species and class of material, Iowa, 1954 

On mi llion c ubic feet) 

Growing s tock Other material 

Species Total Sawtimbe r tree s Sound Rotten Hardwood 

Total Sawlog Upper Pole· Total cull cull limbs 

portion stem.!_; timber u v i_! 

Percent 

Eastern redcedar • • " .. .. 0 3.8 0. 2 3.8 1.0 0. 2 2 . 6 

Black ash • • • . 0 .. ..... 13. 1 .7 1!.4 6.4 1. 4 3.6 1. 7 0.4 0 . 2 1. 1 

American e lm ••.• . •• . • 321.9 16.2 206. 6 115.1 45.4 46.1 115.3 36. 1 9.0 70. 2 

Slippery elm ........ 0. 125.7 6.3 88. 2 51.0 16.3 20. 9 37.5 9. 8 6.7 21.0 

Aspen • ••••• 0 •• • •• • 17.2 .9 15.0 2.7 . 6 11. 7 2.2 .4 1.3 .5 

Cottonwood • • . .. .... . 154.1 7.8 120. 4 92.2 23. 3 4 .9 33.7 1.0 1.9 30. 8 

Basswood . .•• • •• •• •• 111.3 5. 6 83.0 55.0 15.6 12.4 28.3 4.2 8. 4 15. 7 

Silver maple .. . . ..... 183.7 9.2 113. 9 71.0 21.1 21. 8 69.8 24.3 12.0 33. 5 

Sycamore ... . .. .. . . . 0 2.2 . 1 1. 7 1.4 .3 4~6 .5 .5 

Hackberr y .•.. • •••• , , 13.6 .7 9 .9 4. 4 1.5 3.7 1. 9 .3 1.5 

Willow ••••••• ••.• •• 90.0 4.5 6 1. 9 22.6 8. 2 31. 1 28. 1 10.5 7.9 9.7 

Other soft hardwoods . ••• 60. 7 3.0 25. 6 12. 8 4.9 7.9 35. 1 10. 6 14.0 10.5 

White oak • • • • • • • . ••• 167.6 8.4 132.5 76. 1 24.9 3 1. 5 35.1 10 . 2 1.3 23.6 

Other white oaks ....... 177. 6 8. 9 112. 2 60.0 23.3 28.9 65.4 33 . 5 3 . 9 28.0 

Northern red oak . ... . . 166. 0 8.4 126.8 84.3 24. 5 18.0 39. 2 5.4 8.2 25.6 

Other red oaks , • • • •• • • 98.4 5.0 65.6 36.9 12 . 0 16. 7 32.8 10. 5 9.0 13.3 

Hickory 0 0 0 "0 0 0 0 • 0 0 D 78.3 3.9 63. 6 24. 1 7. 7 31.8 14.7 7.8 1. 7 5. 2 

White ash •• •. • • • • .• • 60.1 3. 0 45 . 5 25. 3 8.6 11. 6 14 . 6 3. 0 2.4 9.2 

Sugar maple. , .• , , , , •• 38.8 2. 0 24.9 15. 1 5.0 4.8 13.9 3 . 0 3.9 7.0 

Black walnut , • •• • •• • • 70.7 3.6 52. 8 31.6 9 . 7 11. 5 17. 9 7.1 2.4 8.4 

Other hard hardwoods ... 29.2 1.5 16. 7 8.1 2.5 6.1 12.5 7.2 1.0 4 . 3 

Noncomm. species .. ... 2. 5 .1 2. 5 2.5 

Total • • • 0 • . . . . . .. . 1,986.5 1,382. 0 79 7.1 257.0 327.9 604.5 189. 4 95.5 319.6 

Percent • . • • • 0 . .. . .. 100.0 69. 6 40.1 13.0 16. 5 30.4 9.5 4.8 16.1 

!.I Central stem between sawlog merchantable top and a point with a minimum diameter of 4 i nches inside bark 

u Sound volume of central stem of sound c ull tr ees 

v Sound volume of central stem of rotten cull trees 

ii L imbs of both merchantable and cull hardwood trees 

~ Less; than 0 . 05 million cubic feet 

41 
TABLE 26 - Average volume of growing stock per acre by stand-size class and geographic region, Iowa, 1954 

Board-foot volume 

Stand- size class Total Northeastern Southeastern 

Large sawtimber stands . • 4,541 4,570 3,996 

Small sawtimber stands .. 3,377 3,293 3,697 

Pol etimber stands • • •..• 600 794 508 

Seedl ing and sapling 

stands ••.••• . •• - .• . 411 636 313 

Nonstocked and other 

areas ..... ....... 466 580 472 

Total .. . .. . ....... 1,962 2,530 1,441 

Cubic-foot volume 

Stand- size class T o tal Northeastern Southeastern 

Large sawtimber stands • . 1021. 8 1034. 0 926. 3 

Small sawtimber stands .. 997.4 989.5 992.9 

Poletimber stands • •• ••• 326.6 357. 7 311.1 

Seedlin g and sapling 

stands .• . . . . . . . ~ . . 11 1. 5 179.5 87.0 

Nonstocked and other 

areas . . . ... . ...... 121. 8 149.1 127.8 

Total ... ...... ... 532.6 667.1 420. 0 

TABLE 27 - Numb er of sound tre es on commerc ial for est area b) specie s and tree-diameter c la ss, Iowa, (Thousands of tre e s 

Tree-diameter class i n inches 

Species Total 2 4 6 8 10 12 14 16 18 20 

Eastern redcedar 4,259 1,2 17 1, 704 615 563 86 50 24 

Bl ack ash ••.•.• . 2,265 1,471 147 122 244 86 61 73 37 24 

American elm • • . .. 32, 718 5,396 6,140 6, 732 3,750 3,615 1,990 1,563 1,245 761 516 

Slippery elm 0 .. .. . . . .... 12,959 249 3, 189 3,030 2,195 1,382 972 676 406 455 184 

Aspen . . .. . . .. .... . 5, 709 1, 704 1, 704 830 608 681 134 24 24 

Cottonwood • . • .• ••..• 7,531 2,488 1,465 566 418 394 308 357 307 172 246 

Basswood . ••• . .•••.. 9,570 535 2,686 1,274 1,537 805 722 588 577 417 196 

Silver maple .... .. .. . . 15,299 7,906 498 1,530 1,086 1,309 828 506 480 381 197 

Sycamor e ...... . . .. .. 36 24 

Hackberry .••.••• • . . • 2,426 736 716 495 198 110 61 49 25 

Willow .. .• . ••• • .•. . 13, 115 4,142 1,460 1,606 2,378 1,609 926 589 172 - 148 12 

Other soft hardwoods . •.. 4,322 487 1,398 786 514 550 306 147 110 12 

White oak • . •••. . . .•• 19,989 1,492 3,969 4,801 2,608 2,407 1,549 1,291 750 517 260 

Other white oaks . .... . . 22,002 2,195 6,415 4,229 2,504 2,190 1,687 1,084 787 369 247 

Northern red oak ..••.•. 11,235 1,228 487 2,337 1,592 1,420 1,315 968 600 540 281 

Other r e d oaks •.. •. •• . 14,0 12 243 5,938 2,996 1,630 1,080 621 684 293 159 171 Hickory . .. . . . . . .. . . . 45,682 22,577 9,918 6,338 2,708 2,116 1, 141 540 282 37 25 

White ash •• • •••.. .. . 4,377 243 990 1,008 1,081 466 196 135 123 37 

Sugar maple . .. .. ..... 3,321 492 973 733 514 293 122 73 49 36 12 

Black walnut . • •• . •.•• 7,912 973 1,466 1,405 1,082 886 798 552 467 135 74 Other hard hardwoods ... 12,418 5,917 2,463 1,35 1 616 369 589 360 159 223 160 

Total • • . . • . • . • • • . 251,157 61,691 51,465 43,666 28,273 22,064 14,694 10,442 6,990 Lt,559 2,617 

42 

Western 

5,093 

2,806 

538 

588 

368 

2,135 

Western 

1954 

22 

395 

98 

98 

160 

172 

12 

12 

172 

1107.8 

1038. 9 

318.3 

145.1 

91.7 

553 . 5 

24+ . 

615 

123 

712 

73 

406 

12 

24 

61 

12 

173 

110 185 

233 234 

6 1 136 

98 

12 12 

37 37 

76 135 

1,648 3,048 
TABLE 28 - Average 10-year diameter growth by species and tree-diameter class, Iowa, 1954 

Tree diameter class in inches 

Species 4-8 10 - 14 16 - 20 

Number Inches Inches In ches 

Red cedar 4 1.14 2.40 

Black ash . •• lS .4S 1. 97 1.47 

American elm 278 2.32 2.74 2.40 

Slippery elm 128 2-.s9 2.0S 1.87 

Aspen 12 2.3S 1.30 

Cottonwood •• 6S 2.60 4.2S 3.49 

Basswood .••• 104 1.63 1.94 1.81 

Silver maple .. 99 3.13 3.91 3.74 

Hackberry ••••.• 14 1.30 2.43 2.18 

Willow •••.••••• 78 2.88 3.28 3.26 

Other soft hardwoods •••• S8 2.SS 1.94 1.68 

White oak .... .. .... . 216 1. 79 1. 68 1.96 

Bur oak 0 ••• • •• 186 1.21 1.37 1. 79 

Other white oaks 16 .88 1.06 2.27 

Black oak ••• •. •• 48 2.43 1.60 1.SS 

Northern red oak ••• 139 .99 1.S6 l.S9 

Other red oaks •••••••• 68 1. 76 1. 74 1.S8 

Hickory ....... lSO 1.42 1.31 1.32 

White ash ••••.••••.• SS 1.9S 1.91 2.00 

Sugar maple •.•••••••• 34 1.28 1. 67 2.S4 

Black walnut •.•••. 66 2.12 1. 83 1. 81 

Other hard hardwoods .. . 21 2.43 2.0S 2.08 

Total ............ l,8S4 1.84 2.11 2.13 

TABLE 29 - Average annual net board-foot growth by syecies expressed as a percentage of 

sawtimber inventory volume, fowa, 1954 

Growth on 

Species original stand Ingrowth 

less mortality 

Percent Percent 

Eastern redcedar 0.9S 3.SO 

Black ash •••• 3.97 . Sl 

American elm •• 2.84 1. lS 

Slippery elm .. 3.SO 1.31 

Aspen ...... S.40 7. 4S 

Cottonwood ••• 3.37 .18 

Basswood •• 2. 70 .93 

Silver maple S.S3 1.32 

Sycamore .. 2.03 2.30 

Box elder .. 1. 94 6.9S 

Butternut .. 4.80 2.14 

Black cherry 2.19 2. 70 

Hackberry •• . . . . .. . . . . 3.29 1.S7 

Willow . . . . ......... 6.82 1.91 

Other soft hardwoods •••• 6.68 3.44 

White oak ••••••• 2.63 1. 22 

Bur oak ........ 2.49 1.49 

Other white oaks 3.71 1.0S 

Black oak •••.•• 2.63 .98 

Northern red oak •• 2.24 .64 

Other red oaks • .16 2.2S 

Hickory ... 2.69 2.68 

White ash •• 2.14 1.20 

Sugar maple ••• S.98 .88 

River birch ••••• • 2.93 .62 

Black walnut • •••• 4.40 1.31 

Other hard hardwoods ... 3.86 2.29 

All species .... ..... 3.23 1.18 

22 + 

Inches 

2. 79 

1.63 

2.98 

1. 78 

3.83 

3.80 

3.60 

1..93 

2.17 

2.7S 

3.30 

2.12 

3.11 

1.98 

2.13 

2.8S 

1. 60 

2.61 

Net Growth 

Percent 

4.4S 

4.48 

3.99 

4.81 

12.8S 

3.SS 

3.63 

6.8S 

4.33 

8.89 

6.94 

4.89 

4.86 

8. 73 

10.12 

3.8S 

3.98 

4. 76 

3.61 

2.88 

2.41 

S.37 

3.34 

6.86 

3.SS 

S.71 

6.lS 

4.41 

43 
TABLE 30 - Potential timber volumes and annual net growth in 1965 and 1975. 

timber requirements and progress in forestry. 

Under certain assumptions as to future 

Timb e r Volume 

1954 1965 1975 

All growing stock: 

(millions of cubic feet) . 1, 382 1,837 2,233 

Sawtimber only 

(millions of board feet) • 5,092 6,407 7, 677 

u 

1954 

68 

224 

Annual Net Gro w th 

1965 

71 

247 

1 975 

75 

266 

l! The outlook for timber volumes and net annual growth in 1965 and 1975 is based on assumptions that the annual timber 

products output in the United States and Iowa will rise with e stimated increases in population, national income, and the position of wood in the national economy. Also, that forestry will continue to progress at the rate indicated by re cent trends 

i n cluding advances in protection, management, and reforestation. These projections we re devel oped from trends for the entire Central States as prepared for the upper level of future timber requirements shown in the preliminary review draft of the 

Timber Resource Review. These trends are pre dica ted upon anticipated future timber product demands on the Central States 

forests , a continuing patt e rn of reforestation, a "thickening up• of n a tural stands, and other chang es leading to a more productive forest resource. 

ST ·AND ARD SUMMARY TABLES 

As each state throughout the Nation is reported upon by the Forest Survey, a standard s et of 

tq.bles presenting information on forest area, ownership, timber volume, growth and drain are presented. 

With such tables, forest statistics for any region or group of states can easily be comoiled. Standard 

tables prepared for the State of Iowa, based on the 1954 survey, appear on the following pages. In 

these tables the northern hardwoods forest type appears as the beech- birch- maple type, to conform to 

the patte rn of national summaries. 

TABLE 31 - Land area by major classes of land, Iowa, 1954 

Class of land 

Forest land: 

Commercial •.••. . •• • • .• • . •• , • . . 

Noncommercial: 

Productive -

reserved from timber use . 

Unproductive • , , , , , , •• , 

Total fore st land • , 

Nonforest land , , 

Total all classes 

Area 

Thou s and 

a cr es 

2 ,595 

25 

0 

2 , 620 

33,249 

35,869 

TABLE 32 - Commercial fore st area by owners hip and stand-size c la ss, Iowa , 1954 

On thou sand a c res) 

Ownership class T o tal 

Federal: 

National Forest , . .. .. . . .. . . . . . . . 2. 7 

Indian . .. .... . . . . ~ . . 1.0 

Other . .. . . .. 9.2 

Tota l • .. 12.9 

State .. . . . . . .. . . . 22.0 

County and Municipal . . . ... .... 1.9 

Private: 

Farm., ... . . . . . . 2, 282.1 

Industrial and othe r • 276.1 

Total . ... 2,558.2 

All ownerships. ... . . . . 2,595 

44 

Larg e Small 

s awtim b e r s a w timb e r 

s tand s stands 

0.2 0. 1 

. 1 . 1 

2. 5 1.0 

2.8 1.2 

5. 7 2. 4 

. 3 .2 

654. 3 23 8.8 

74. 9 25.4 

729.2 264.2 

738 268 

P o l e -

timber 

stand s 

2 . 2 

. 6 

3.5 

6.3 

7 . 2 

1.0 

726.8 

88.7 

815.5 

830 

Se e dlin g 

& s a pling 

s tands 

0 . 2 

.2 

2. 1 

2 . 5 

2.8 

. 3 

247.4 

34.0 

281.4 

287 

Percent 

7.2 

. 1 

.o 

7. 3 

92.7 

100.0 

N o nsto c k e d 

and other 

are as 

0.1 

.1 

3.9 

. 1 

414.8 

53. 1 

467.9 

472 
TABLE 33 - Area of commercial forest land 

by major forest types, Iowa, 1954 

Forest type 

Oak hickory ••••••• 

Maple - beech· birch •• 

Elm - ash- cottonwood 

Aspen-birch .•••• 

Bur oak •••••••• 

Hardwood -redcedar. 

Total •.•••••• 

Thousand acres 

1,036 

78 

1,219 

20 

202 

40 

2,595 

TABLE 34 - Net volume of live sawtimber and growing stock on commercial forest land by stand-size class, Iowa, 1954 

Stand-size class Sawtimber Growing stock 

Million board-feel Million cubic feel 

Sawtimber stands . 4,257 1,021.4 

Poletimber stands. 497 271.1 

Seedling and 

. sapling stands • 118 32.0 

Nonstocked and 

other areas. 220 57.5 

Total .... 5,092 1,382.0 

TABLE 35 - Net volume of live sawtimber and growing stock TABLE 36 - Net volume of live sawtimber and growing stock 

on commercial forest land by ownership dass, Iowa, 1954 on commercial forest land by species, Iowa , 1954 

Ownership class 

Federal: 

National Fore s t. 

Indian. 

Other 

Total 

State .• 

County and Municipal 

Private: 

Farm. 

Industrial and other 

Total • • .•• 

All ownerships, 

Volume 

Sawtimber Growing Stock 

Million board-feet Million cubic feet 

4 

3 

21 

28 

40 

3 

4.515 

506 

5,021 

5,092 

1.1 

o. 7 

5.7 

7.5 

11.4 

1.0 

1,225.0 

137. 1 

1,362.1 

1,382.0 

Species 

Softwoods: 

Eastern redcedar •• 

Total softwoods 

Hardwoods: 

White oaks. 

Red oaks •• 

Other white oaks • 

Other red oaks 

Sugar maple 

Soft maple ••• 

Ash ....... Hickory •• : • . 

Cottonwood 

Black walnut 

Other eastern 

hardwoods. 

Total hardwoods 

All species .•••• 

Volume 

Sawtimber Growing Stock 

Million board-feet Million cubic feel 

6 3.8 

6 3.8 

504 132.5 

532 126.8 

383 112.2 

231 65.6 

98 24.9 

462 113.9 

200 56.9 

155 63.6 

601 120.4 

193 52.8 

1,727 508.6 

5,086 1,378.2 

5,092 1,382.0 

TABLE 37 - Net volume of live sawtimber on commercial forest land by diameter class groups and species, Iowa, 1954 

On million board-feet) 

Tree diameter class (inches) 

Species Total 12. 14 16 - 18 20 + 

Softwoods: !_/ Eastern redcedar ••• 6 6 

Total .• • • • Q ••• 6 6 

Hardwoods: 

White oaks. 504 198 166 140 

Red oaks • • 532 147 174 211 

Other white oaks • 383 144 113 126 

Other red oaks 231 84 64 83 

Sugar maple 98 35 26 37 

Soft maple . 462 86 124 252 

Ash .••• • 200 57 55 88 

Hickory •.• 155 108 43 4 

Cottonwood 601 53 85 463 

Black walnut.. 193 85 76 32 

Other eastern hardwoods • 1, 727 537 575 615 

Total .• 5,086 1,534 1,501 2,051 

All species. 5,092 1,540 1,501 2,051 

!_/ Includes 10° softwood sawtimber 

45 
TABLE 38 - Net volume of all timber on commercial forest land, by class of material and species group, Iowa, 1954 

(In million cubic feet) 

Class of material 

Growing stock: 

Sawtirnber trees: 

Sawlog portion • • Upper stern portion •• • 

Total •• .•. 

Poletimber trees •• • 

Total growing stock • • • •• ••• • ••• 

Other material: 

Sound cull trees • ••• 

Rotten cull trees • •• •• •••••• • ••••• 

Hardwood limbs •••• ••• 

Salvabh. dead trees •••••••• • ••• • 

Total other material ••••••••• 

Total all timber ••• • ••••• • •••• ; • 

T ot a l 

797. 1 

257.0 

1,054.1 

327.9 

1,382.0 

189.4 

95.5 

319.6 

604.5 

1,986. 5 

Softwoods 

1.0 

0.2 

1.2 

2.6 

3.8 

3 . 8 

Hardwoods 

796.1 

256. 8 

l, 052. 9 

325.3 

1,378.2 

189.4 

95.5 

319.6 

604.5 

1,982. 7 

TABLE 39 - Net annual growth, annual mortality and annual cut of live sawtimber and growing stock 

on commercial forest land by species groups, Iowa, 1954 

Item 

Net anrrual growth ••••• • •• • • • ••••••• 

Annual Mortality •••• • ••• • • •• Annua l cut: 

Timber products • Logging residues. 

Total ••• • •• • 

!...! Less than • 05 million cubic feet 

Total 

224.3 

26.6 

98.7 

3.9 

102. 6 

Sawtimber 

Softwoods 

Million board-feet 

0.3 

.1 

1.2 

1.2 

Hardwoods 

224. 0 

26.5 

97.5 

3.9 

101.4 

Total 

67.9 

8. 2 

20.6 

1.4 

22.0 

Growing Stock 

So ft- Hardwoods 

Mill ion cubic f eet 

0.2 

!_I 

.3 

woods 

67.7 

8.2 

20. 3 

1.4 

21. 7 

TABLE 40 - Output of timber products and annual cut of live sawtimber and growing stock, Iowa, 1953 

Output of Timber Products .u Annual Cut of 

Roundwood volume Annual Cut of Sawtimber Growing Stock 

Product (Thousand Cubic-feet) (Thousand Board-feet.£/ ) (Thousand Cubic-feet) 

Volume in standard units Total Soft- Hard- Tot al Soft- Hard- T otal So ftwoods woods woods woods "" woods 

Units Numb er 

Sawlogs • • • •• • •• • M bd.-ft. :u 65,000 ~/ 9,600 240 9,360 67,500 

Veneer lo gs 

and bolts ••• •• • • M bd.-ft. 4, 700 700 700 4,900 

Cooperage 

logs & bolts •• • •• M bd.-ft. 3,500 500 500 3,600 

Pulpwood • • •• •• Std. Cords '.!_! 3,200 200 200 260 

Fuelwood • . •• •• Std. Cords 383,400 24,000 24,000 20,000 

Posts . •••• • • • M pieces 2,400 1,200 1,200 3,700 

Miscellaneous . M Cu. ft. 400 400 400 2,600 

Total .... .xxxx xx xx 36,600 240 36,360 102,560 

!.../ Includes material from both growing stock and other miscellaneous sources 

;Li International 1 /4-inch rule 

1,200 66,300 12,000 

4,900 830 

3,600 620 

260 200 

20,000 7,400 

3,700 610 

2,600 380 

1,200 101,360 22,040 

/ Sawlog production is based on several independent studies of timber cut in Iowa in the period 1952-1954 

'.!_! Rough wood b asis 

Agriculture 

46 

BEAVER PRESS 

COLUMBUS, OHIO Columbus, Ohio 

275 

275 

Hardwoods 

11, 725 

830 

620 

200 

7,400 

610 

380 

21, 765 
Acknowledgment 

··~·------------------------------··(9N..o·· 

This is the final report of the findings of the initial Forest Survey in Iowa. A 

preliminary report including timber volume and forest area statistics was released 

in July 1956. These publications are products of the nationwide Forest Survey being 

made by the Forest Service, U. S. Department of Agriculture. 

The preliminary planning and a large part of the field work were do_ne by personnel of the Central States Forest Experiment Station at Columbus, Ohio. Compilation 

of data and preliminary report preparation were done at the Lake States Forest 

Experiment Station at St. Paul, Minnesota. This final report is the result of a cooperative effort by both organizations. 

Field work in Iowa was done m the period November 195 3 to August 195 4. 

From initial planning to final compilation, the following people took part in this 

inventory: 

Supervision and planning-R. N . Cunningham, ]. T. Morgan. 

Photo interpretation-K. E. Moessner, P. L. Thornton. 

Field inventory-P. L. Thornton, ]. D. Burton, A. R. Eschner, N. ]. Hansen, 

K. Kuusela, M . ]. Peterson, W. C. Ritter, D. E. Stoppel. 

Statistical Computatio-ri.s-L. F. Compton, C. E. Jensen, M. K. Peirsol. 

Timber-wt estimates-0. K. Hutchison, A . L. Hartong. 

The Forest Survey in Iowa was intensified beyond the accuracy required for national compilations (and thus made more useful locally) through the cooperation 

of two State agencies. The State Conservation Commission and the Iowa Agricultural Experiment Station aided in the fie ld inventory. This assistance made possible measurements of twice as many ground plots as originally planned. Complete 

aerial photo coverage of the State was loaned by the Iowa Agricultural Stabilization 

Committee at Des Moines. 

Central States Forest Experiment Station, U. S. Department of Agriculture, Forest Service, 

111 Old Federal Building, Columbus 15, Ohio 

W . C. McCi?inies, Director