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Full text of "Native and planted timber of Iowa"

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Historic, archived document 

Do not assume content reflects current 
scientific knowledge, policies, or practices 

Issued September 15, 1908- 
Reprint, May 25, 1911. 


FOREST SERVICE— Circular 1S4. 










Introduction 5 

Purpose and method of investigation 5 

Adaptability of the State to tree growth G 

Topography 6 

Soil G 

Climate 7 

Drainage 7 

Native timber 8 

Distribution 8 

Natural extension ,. 8 

Condition 8 

Utilization 9 

Management of native groves 10 

Protection 10 

Fire 10 

Insects and fungi 11 

Management 11 

Reproduction 11 

Natural reproduction by seeds and sprouts 11 

Artificial reproduction by seeding and planting 12 

Improvement thinnings r 12 

Harvesting the crop 13 

Planted timber 13 

Species 13 

Purpose of planting 14 

Probable causes of success or failure 14 

Planting and care of windbreaks 15 

Species to be used 15 

Seeds or seedHngs 16 

Time for setting trees 16 

Methods of planting 17 

Spacing 17 

Distance and direction from dwellings and orchards 17 

Diagram for proposed windbreak 18 

Care of young and old trees in the windbreak 18 

Tree planting for commercial purposes 19 

Location 19 

Species 20 

Planting 20 

Growth and probable returns 21 


Fig. 1. Diagram for proposed windbreak for average soil and moisture condi- 

» tions in central Iowa 18 

[Cir. 154] 




The increasing demand for agricultural land in Iowa has caused a 
very rapid removal of woodlots and groves during the past five years, 
which has greatly reduced the home supply of posts, fuel, and farm 
repair material. The prices of posts, poles, and lumber imported 
from other States have risen from one-third to one-half in three 
or four years, and since the supply of white cedar and red cedar is 
limited, the price of posts at least will continue to increase. This 
high cost has led many residents of the State to take steps tov/ard 
managing their farm woodlots so as to obtain greater returns from 
them by growing their own fence posts and repair material. This 
tendency toward the practice of forestry largely brought about the 
Bixby forestry bill, passed by the legislature in 1907, which provides 
that lands occupied by woodlots and groves shall be given a taxable 
value of $1 per acre, if certain conditions of the bill are complied mth. 


To aid in the movement toward practical forestry in Iowa, investi- 
gations were made during 1905 by the Forest Service to determine 
the extent, character, and value of the native farm woodlots and 
planted groves. In the studies of natural tree growth, the main 
water courses were followed. Investigations were made of the rela- 
tion of topography and soil to existing tree growth, and of the effect 
of the previous conditon and treatment of the forest upon its present 
extent, composition, reproduction, and enemies. 

In the studies of the planted timber two routes were planned, one 
in the northern part of the State and one in the southern, in accord- 
ance with the answers to letters and question blanks v/hich had bsen 
sent out. Much valuable information regarding the planted timber 
of the State was obtained through these blanks. 

Groves and windbreaks were examined to find out what species 
had been planted and how these species had succeeded under widely 
varied conditions of soil, moisture, and situation. The rate of 
growth of various species was also determined. 

[Cir. 154] 



The surface of Iowa is in general an undulating plain, bounded on 
the east by the Mssissippi River and on the west by the Missouri 
and Big Sioux rivers. The numerous tributaries of these large rivers 
make up the drainage system of the State. As a rule it is only along 
the valleys of these streams that the surface is broken to any extent. 
The difference in elevation between the highest and lowest points is 
so slight (less than 1,100 feet) that the drainage over large areas of 
the State is imperfect, and this affects the value of the land for agri- 
culture or forestry. There is only one main watershed, and that is 
not well defined. It extends in an irregular line from Dickinson 
County on the north to Wayne County on the south. 

On account of the slightness of the differences in elevation and 
other physical characteristics, there is no wide divergence in the 
types of tree growth in the State, and hence the problems of tree 
planting and woodlot management are simplified. There are two 
forest types — one in the low, level, moist areas along streams, made 
up largely of alluvial soils, and the other on higher, well-drained 
slopes and uplands back from water courses, or in scattered areas 
over the undulating prairies. These types merge into each other and 
it is seldom possible to define their boundaries. In the bottom type 
are such moisture-loving trees as cottonwood, willow, honey locust, 
black ash, elm, and coffeetree, and in the upland type are the oaks, 
hickory, ironwood, butternut, white ash, and hackberry. Through- 
out the State the soil is adapted to the growth of forest trees. 


Iowa soils may be divided into four classes — geest, which occurs 
maioly in the northeastern portion of the State and constitutes less 
than 1 per cent of the total area; alluvium, which is usually found in 
stream valleys and forms less than 6 per cent of the total area; loess, 
a wind-formed soil, which covers 66 per cent of the State; and till or 
drift, which is the product of glacier movement, and covers the 
remainder of the State. It was observed that upon the geest and 
drift soils reproduction is more abundant and growth more vigorous 
and that the trees attain a greater age than on either loess or 

Whenever it is possible, trees, especially the slower growing ones, 
should be planted on the sandier and coarser soils of the farm, and 
these soils should be used for growing seedhngs in preference to the 
finer loess or heavier alluvial soils, especially as the finer soils are of 
greater value for agricultural purposes. 

[Cir. 154] 


The rainfall of the State ranges from 30 inches in the immediate 
vicinity of the Mssouri Eiver to 32.5 inches along the Mississippi,. 
There is a gradual decrease in the average annual rainfall from south 
to north and from east to west. The rains are usually the result of 
the meeting of warm, moisture-laden winds from the Gulf of Mexico 
and cooler air currents from the north and west. There are no places 
in the State where the rainfall is insufficient for the perfect develop- 
ment of hardy trees. Although droughts do occur in Iowa, they come 
only at long intervals, generally in the midsummer months ; yet it is 
probable that a greater loss to the State has resulted from excessive 
moisture during the agricultural growing season than from insufficient- 
rainfall. These periods of excessive moisture favor the growth of 

The mean annual temperature is about 47.5°. The transitions 
between winter and summer are much more rapid than in States 
nearer the Atlantic coast. This influences to a marked degree the 
distribution and general growth of trees. Seedlings and often mature 
trees are seriously injured or even killed by frosts in the fall before 
the new wood has become thoroughly ripe. The average date of the 
latest killing frost in the spring has been April 20, and that of the 
earliest in autumn, October 9. 

The prevailing summer winds, which are usually hot and dry, are 
from the south, while those at other seasons are from the west. These 
mnds are almost constant and have a velocity of from 8 to 9 miles an 
hour. The distribution of many tree species is determined largely 
by these constant drying winds, which probably are responsible for 
the treeless condition of the plains. Their injurious effect, which 
can be seen on any exposed windbreak or orchard, may be minimized 
by planting protective borders of low-growing, hardy trees on the 
exposed sides. Planting of windbreaks and groves in the State 
during the past fifty years has probably modified the severity of 
mnds, but to what extent is not known. These strong mnds stimu- 
late transpiration from the leaves of the trees during the growing 
period, and increase the evaporation from the soil during the dormant 
season. This latter causes damage by mnter killing. 


The imperfect natural drainage of parts of the State has resulted in 
scattered, swampy areas, some of which are of very large extent. 
Since land is rapidly increasing in value these areas are gradually 
being drained and utilized for farming purposes. On swampy areas 
which are difficult to reclaim by drainage, arborvitse, tamarack, mllow, 
and Cottonwood can be grown successfully, and in addition to the 

[Cir. 154] 


posts, repair material, and fuel they will produce, they may he of great 
value in the ultimate reclamation of the soil by taking up immense 
quantities of water and depositing layers of organic material on the 




When white men came to Iowa it is estimated that a fifth of the 
State was forested. The eastern portion of the State was pretty well 
covered. The best growth was along the larger rivers, but it often 
extended many miles away from the banks. Occasional small groves 
were found on the prairies. Through the southern and western parts 
and along the Des Moines River and its tributaries in the central part 
there were scattered groves. 

The principal tree species in the early forests were practically the 
same as those found to-day, bitternut and pignut hickories, and black 
walnut; white, bur, red, yellow, and swamp white oaks; soft, or silver, 
and hard, or sugar, maples; white and green ash; white, slippery or 
red, and cork elms; hackberry, basswood, cottonwood, black willow, 
sycamore, honey locust, and coffeetree, besides others of less im- 


Where natural extension of timber took place, it spread from the 
main bodies along the Mississippi and Missouri rivers and followed the 
tributaries of those rivers. That it did not extend farther up the 
streams and outward across the prairies was due principally to prairie 
fires, which annually and often semiannually swept over a large part 
of the State. Natural extension was more uncertain and slower in the 
western part of the State than in the eastern, because of less abundant 
rainfall, greater exposure to hot, dry winds^ and greater frequency of 
prairie fires. In many cases forest growth extended farther up the 
southern bank of streams than the northern, and covered larger areas 
on that side. This was due probably to the fact that snow was not 
reached by the sun as quickly on the southern bank, and so lasted 
longer. The spring fires destroyed the trees on the dried-out northern 
bank, but were checked by melting snow on the other side. 

As settlement, which began in the timbered portions of the eastern 
part of the State, extended westward across the prairies, many of the 
causes of prairie fires were removed and immediately the forest growth 
began to extend farther up the streams and back to the uplands. 


The original timber aieas consisted largely of scattered groups of 
trees surrounded by brush and grass. In the eastern part of the State, 

[Cir. 154] 

where conditions of growth were most favorable, there were tracts of 
forests that compared well with the best virgin timber in the Ohio 
Valley. The best specimens of oak, walnut, and sycamore were often 
from 4 to 6 feet in diameter and from 80 to 100 feet high, but in the 
settlement of the region these soon disappeared, and have never since 
been equaled in the State. 

Throughout the central and western portions of the State the 
streams were fringed with thin belts of trees, but usually back of these 
the growth was poor and scrubby, suitable only for the protection of 
stock, for a poor grade of posts, and for fuel. 


In the more heavily timbered portions of the State the early settlers 
utilized the best timber for the construction of buildings and fences. 
The westward extension of railroads had much to do with the exhaus- 
tion of the timber. Every accessible tree that would make a bridge 
timber or sleeper was cut almost before the prairie sections of the 
State were settled. Even before the railroads reached the valleys of 
the Cedar and Iowa rivers much of the best red cedar and walnut 
along these rivers had been cut and rafted to the Mississippi for the 
down-river trade. Again in the early eighties a very thorough canvass 
of the eastern and central parts of the State was made by furniture 
manufacturers, and most of the best walnut was taken out. This 
thorough removal of the virgin timber of the State soon necessitated 
the importation of softwood lumber and cedar posts. These are now 
increasing so rapidly in value that many consumers are being forced 
to use cheap grades of pine, hemlock, and hardwoods. Portable saw- 
mills are operating wherever timber is found, and the best of the second- 
growth woods and planted timber is being utilized. Cottonwood and 
silver maple have been found very valuable for construction purposes 
where the wood is not exposed to the weather, and they sell for from 
$22 to $28 per thousand board feet. 

The high price of lumber and posts and the rising value of farming 
land is causing the clearing of many hillsides and ridges in the eastern 
part of the State. Many of these ridges are not fit for agricultural 
purposes themselves and moreover are a menace, since raiiis and melt- 
ing snows erode them and spread the soil and debris over the fertile 
lands below. The removal of the forests has led also to floods and to 
the disappearance of springs and small streams. More than this, it 
has very considerably lowered the water table in the soil. In southern 
Wisconsin the lowering of the water table has resulted in the death of 
many large trees, which could not send out new roots and adapt 
themselves to the changed moisture conditions of the soil. The dying 
out of many old trees in eastern Iowa is probably due to this same 

92428— Cir. 154—11 2 



Iowa has a smaller proportion of nonagricultural land than any- 
other State, and this is being decreased each year by turning unpro- 
ductive areas into orchards, pastures, and ranging ground. With 
the development of the fat-stock and dairy industries there will be an 
increasing demand for grazing lands, and this in turn will cause the 
clearing of large tracts now held as woodland. 

However, from 10 to 15 per cent of the State will remain in timber, 
and this portion should be so managed as to yield at least fair profits 
from the soil. Notwithstanding the excellent farming methods in the 
State and the increasing desire of the settlers to improve those methods, 
little attention has been paid to increasing the returns from the 

Formerly the farm woodlots were used commonly for pasture; this 
practice, when the annual fires killed the old mature trees, prevented 
new growth from coming in. When posts, poles, or fuel are needed it 
is seldom possible now to secure them from the woodlot which should 
furnish them, and the farmer must purchase them from the local 
lumberman at a constantly increasing price. 

Protection. — Shade and protection for stock is necessary, but it is 
a detriment to the stock to pasture them exclusively in woodlots, for 
grass growing under trees has but a small percentage of the food value 
of that grown in the open, and much better results for both cattle and 
trees can be obtained if from half an acre to an acre of ground for 
shelter is planted to silver maple or willow, setting the trees close. 
When the planting is from 3 to 5 years old, cattle or horses may 
be allowed free access to it from large pastures, and even if the silver 
maple is gradually killed out the loss will not be as great as if the 
whole woodlot were used. 

If moje pasture land is needed on the farm, half the woodland may 
be cleared and turned into good grassland. If the remaining half is 
protected from fire and stock and a few careful thinnings are made, 
it will become a perpetual source of wood for posts, repair material, 
and fuel. 


Every spring and fall, when the damage from fire is greatest, the 
groves should be closely watched, especially if they are located near a 
railroad. If old roads or paths run through the tract, they should be 
raked clear of brush and leaves at least twice a year. When kept 
clean, they prove very effective in stopping surface fires. 

Where there is constant danger from fire, strips two or three furrows 
wide and a rod apart should be plowed around the grove, if possible. 
If highways run along the sides of a grove and there is danger of fire 

rCir. 154] 


from cigar stubs or matches, the herbs and shrubs should be cut, and if 
necessary the roadway burned over. 

When trees are cut in the woodlot, all branches and smaller Umbs 
should be utilized as fully as possible for fuel. Those which can not be 
utihzed should be taken to an open space and burned or cut up and 
spread over the ground to hasten their decay. 

The tools best suited for fighting fires in woodlots are heavy rakes, 
with which paths may be cleaned m front of advancing flames. 
Shovels are very useful where the soil is light and can be easily thrown 
upon the fire. It will not be necessary to back fire except in rare cases^ 
and then it should be done by raking a path parallel to and some dis- 
tance ahead of the fire, and starting small fires along this path to 
destroy debris so that when the two fires meet they will die out for 
lack of material. 


Since farm woodlots are usually small in area and widely separated 
by cultivated fields, roads, and streams, there is less danger of exten- 
sive infestation by insects and fungi than where forests occur in solid 
bodies of wide extent. If insects are unusualty abundant and are 
doing much damage to the trees, specimens should be sent to the 
Bureau of Entomology of the United States Department of Agricul- 
ture, which will identify them and give suggestions for combating 
them. Where single trees seem to be dying out as a result of a rot 
or of insects, they should be removed, and all portions of the tops 
not suitable for fuel should be burned at once. In pruning, care 
should be taken to cut the limbs close to the trunk in such a manner 
that water can not find lodgment. • The entrance of the spores of 
fungi may be largely prevented if wound surfaces on trees are painted 
over mth white lead. 


Reproduction. — The following suggestions for the reproduction 
and care of woodlots are given with the presupposition that stock 
and fire are to be excluded. Should it be necessary to use a part 
of the tract for pasture, it may be divided into sections and each 
section fenced oft' in succession, until reproduction in each can be 

Natural reproduction hy seeds and sprouts. — The woodlots through- 
out the State are made up of hardwoods, most of which sprout readily 
from the stump. A large part of the timber in these woodlots has 
come from stump sprouts, which, under conditions of healthy grow^th, 
make trees of a size suitable for posts and logs in a shorter time 
than it took the original tree to grow. Because of the ease and cheap- 
ness of this method of reproduction, it is likely to be used more exten- 
sively than any other. Trees cut during the mnter sprout better 
than those cut at other seasons, but for reasons explained later, 

[Cir. 154] 


•winter cutting is not always desirable. The stumps should be cut as 
low as possible and left with a slanting surface, so that water will run 
off readily. The lower the stumps, the less danger there will be of 
the sprout being broken by wind and the quicker the new tree will 
form independent roots of its own. The oaks, ashes, mulberry, bass- 
wood, walnuts, and hickories may be very readily reproduced by 
stump sprouts, and the trees so formed are straighter and of more 
rapid growth, and the wood is as durable as that from trees which 
have grown directly from seed. A woodlot constantly reproduced in 
this way will gradually run out as the vigor of the original stumps 
fail and must eventually be replaced by trees from seed naturally 
so^vQ or from planted seed or seedlings. 

The exclusion of fire and stock will favor the natural seeding of 
the woodlot from trees already standing on the ground. If the 
ground is covered by heavy sod or herbaceous growth, natural seed- 
ing can be greatly aided by stirring up the soil with plow or mattock 
just before a crop of seed falls, so that the seeds may reach the mineral 
soil. This method of reproduction is slow, however, and mth the 
small areas occupied by woodlots it is feasible to plant the open spaces 
with seedlings of the desired species, and thus shorten the rotation of 
the crop, and hence increase the returns. 

Artificial reproduction hy seeding and planting. — Usually where a 
stand of walnut, butternut, or red oak is desired, the nuts or acorns 
may be planted directly w^here the tree is to stand. Spring plant- 
ing of nuts and acorns is more advisable than fall planting, provided 
the nuts are properly stored during the winter. If spaces to be 
restocked are of large size the seeds may be planted 6 feet apart each 
way in regular rows, or irregularly so that in the ultimate stand, 
including large trees, the spacing is approximately 6 by 6 feet or a 
little greater. The precaution should be taken to plant seeds of trees 
which will endure more or less shade. 

If it is desired to underplant the woodlot with conifers or some of 
the quicker growing hardwoods, hke honey locust or catalpa, seed- 
lings from 1 to 4 years old should be used. Seedlings should be spaced 
as suggested for seeding. Some of the best trees for underplanting, 
besides those already mentioned, are white pine, white spruce, hem- 
lock, sugar maple, hackberry, and hardy catalpa. 

Improvement thinnings. — If after the young seedlings in a wood- 
lot are well started they are left entirely to themselves, the struggle 
for light and space will be so great that many good specimens of the 
most valuable species will be killed out and such worthless weed trees 
as ironwood, blue beech, hawthorn, and prickly ash, through their 
ability to reproduce and grow in shade, will thrive in their place. If 
at that time a little judicious thinning is done, nature will be greatly 
aided in her production of valuable material. Too often the best 

[Cir. 154] 


trees are selected and cut every time a piece of wood is wanted. If 
mature, dying, or worthless species are removed with care so as not 
to injure the young growth, the grove will constantly improve in com- 
position as the place of the overmature, diseased, and worthless trees 
is taken by the better young growth. 

In an old woodlot which is badly run down, thinnings should begin 
at once and be repeated often, but at no time should trees be removed 
in such a way as to permit the formation of extensive areas of brush 
and grass. If only large, overmature trees are present, they may be 
cut in groups and the vacant area sown to acorns or nuts, or planted 
with valuable species which can endure shade. In this way all the 
large trees may be gradually removed and the area restocked with 
valuable young forest growth. 

Great care should be exercised in all thinnings, especially on hill- 
sides and ridges, not to cut out so heavily as to expose the soil to ero- 
sion. This washing away of valuable soil and the formation of gullies 
is each year destroying large areas of land in Iowa. Two hundred 
square miles is said to be so lost each year in the United States, and 
Iowa is doing more than her share toward increasing this figure. 

Harvesting the crop. — The best time to cut the trees to insure 
sprout reproduction is in winter or early spring, and the wood of 
sprouts which form in early spring has ample time to ripen before 
winter. However, if the trees are cut between late July and Sep- 
tember, during what lumbermen call "the second running of the 
sap," and then left to lie for several days, until the leaves are com- 
pletely wilted, seasoning will take place rapidly and thoroughly after 
the posts or poles are peeled. Peeling should be done at once, and 
the logs should be piled so that no part touches the ground. Posts 
so treated will greatly outlast those of the same species and size cut 
in winter and stacked on end without peeling. Trunks should not 
be left lying on the ground before utilization, as this invites attacks 
of fungi and insects and hastens rot. 



When the people learned that the prairie soil was as valuable for 
agricultural purposes as that of the hardwood regions, and the settle- 
ment of the State began to extend westward from the timbered lands 
along the Mississippi, there arose a need for the protection of the new 
homes from the severity of hot and cold winds. Since the need was 
immediate and seeds and seedlings of the softwoods were cheap, 
easily obtained, and gave early results, the first plantings in the 
State were of such species as silver maple, cottonwood, boxelder, and 
willow. The silver maple has been more widely planted in Iowa than 
any other tree because it makes good fuel, when seasoned under cover, 

[Cir. 154] 


and attains a greater age than the other softwoods mentioned. As a 
section of the State becomes older and more wealthy, better homes 
are built and are surrounded by slower-growing, longer-lived trees. 
The planting of evergreens was begun at an early date, as the settlers 
saw that, since they retained their leaves throughout the year, they 
were much more effective for windbreaks than deciduous trees. 


Following the period of planting quick-growing trees on the prairies 
for protection only came the time when anxiety as to future timber 
supplies, aroused by the depletion of the virgin timber by railroads and 
the exploitation of red cedar and walnut, led to the planting of better, 
slower-growing hardwoods. The State law of 1868, which granted a 
rebate of taxes for a certain amount of planting, resulted from this 
fear of a timber famine. Under this law a large amount of planting 
was done, but frauds caused its repeal during the eighties. Altogether 
the law worked for good, since it not only increased the amount of 
planting done, but aroused interest in trees and increased the knowl- 
edge of planting and of species best adapted for the State. In nearly 
all cases the plantations which were made under this law were com- 
posed of soft-wooded hardwoods, and to-day these species form a 
very large proportion of the planted groves. Black locust, black 
walnut, green ash, honey locust, and European larch were planted for 
posts and lumber, and wherever even the slightest attention and care 
was given, such groves, with the exception of the black locust, have 
given good results. The black locust, a few years after planting, was 
destroyed by the locust borer (Cyllene rohinise). Many nurseries 
came into existence between 1865 and 1880, and did much toward the 
introduction of evergreens and more desirable hardwoods. 


There were many failures during the early years of tree planting in 
the State, and there are still many. These failures, however, have 
been useful in supplying knowledge of the best species to plant and of 
the best methods of establishing and caring for plantations. 

The greatest cause of failure was the absence of proper care. Small 
trees of silver maple, green ash, and black walnut were planted in 
groves as close as 3 by 6 feet or 4 by 4 feet. They were not cultivated 
or thinned, and as they became larger many were deformed and 
killed by crowding and lack of moisture. In many cases the groves 
were used for stock yards or feed lots during winter, and browsing 
and trampling prevented reproduction and otten exposed the roots 
and damaged the bark of older trees so that they died. Trees respond 
readily to cultivation and care. They will not succeed to the fullest 
degree if sod is allowed to form about them or if the soil is packed 
down around the roots by the constant trampling of cattle and horses. 

[Cir. 154] 


The use of undesirable species was frequently the cause of failure. 
Such trees as black locust, chestnut, beech, and others which were 
widely used, were total failures because of insect attacks or lack of 


Species to be used. — A greater variety of trees has been planted 
in the State for windbreaks than for any other purpose, but the 
number which can be used successfully is limited. Certain species, 
although not of the greatest usefulness for windbreak purposes 
solely, have a high value for fuel, posts, and farm repair material. 
These may be used to advantage both for windbreaks and the pro- 
duction of wood supplies. The best of these ''dual purpose" trees 
are included in the following list : 

Honey locust. Hardy catalpa. 

European larch. Russian olive. 

Silver maple. White willow. 

Cottonwood. Osage orange (in central and 
Green ash. southern Iowa). 

The black or yellow locust would answer the two requirements 
better than any of the trees mentioned but for its susceptibility to 
the attacks of the locust borer, wliich riddles and kills it within a 
few years. 

Some of the pines and spruces are much more valuable than smj of 
the broadleafed trees for windbreak planting alone. They retain 
their leaves throughout the year and thus provide protection during 
the wdnter when it is most needed. The hardier evergreens may be 
successfully grown under nearly all conditions of soil and moisture, 
and their growth is often more rapid than that of the more permanent 
hardwoods. Climatic and other conditions which influence tree 
growth are more severe in the western part of the State than in the 
eastern counties, and it has been found that certain of the Pacific 
coast and Rocky Mountain conifers do better there than those from 
the East. The evergreens recommended for planting in different parts 
of the State are given in the following list : 

Eastern Iowa. Western loua. 

White pine. Black Hills spruce. 

White spruce. Western yellow pine. 

Norway spruce. Austrian pine. 

European larch. Scotch pine. 

Austrian pine. Douglas fir. 

Colorado blue spruce. • White pine. 

Arbor\dt8e. Colorado blue spruce. 

Hemlock. White fir. 

Scotch pine. European larch. 

White fir. Norway spruce. 
Douglas fir. 

Western yellow or bull pine. 
[Cir. 154] 


The red cedar is not recommended because it is a menace to fruit 
orchards through the spreading of apple rust; one stage of the life of 
this fungus is passed on the branches of the red cedar, when it is known 
as the ''cedar apple." It is also slow in growth and there are other 
evergreens which are more valuable. The arborvitse and tamarack 
require permanently moist situations. 

Seeds or seedlings. — Because of the difficulty and expense of 
raising evergreens from seeds, it is usually advisable to purchase from 
nurserymen seedlings 2 or 3 years old which have been transplanted 
once. These have well-developed root systems and will grow with 
little difficulty. They should be put out in garden soil in rows from 10 
to 30 inches apart and with the trees from 6 to 10 inches apart in the 
row. After two or three years they can be transplanted to the per- 
manent location. By this method better stock is obtained and the 
total cost of the windbreak is reduced one-half or more. There is 
practically no loss from transplanting. 

For the broadleaf trees recommended for planting it will be 
cheaper and fully as satisfactory to collect or buy the seeds and rtiise 
the seedlings. A safe rule to follow in the planting of seeds such as 
those of maple and elm is to plant them immediately after they ripen, 
or before midsummer. Most other seeds should be planted the spring 
following ripening, yet seeds of basswood and Russian olive germinate 
better if planted in the fall. 

In keeping seeds over winter, nature's manner of storage should be 
followed as nearly as possible. Where seeds remain on the tree until 
late winter or early spring, as in the case of catalpa and honey locust, 
they should be collected in late fall and hung up in a dry, cool place in 
porous cloth sacks. Nuts and acorns which fall during the. autumn 
and are buried among the leaves should be stratified through winter in 
boxes of moist sand and planted as soon as the ground can be worked 
in the spring. 

In many instances seedlings of the silver maple, willow, cottonwood, 
green ash, and honey locust can be pulled from the ground in bottom- 
lands, or in groves, and set out very cheaply and v/ith little danger of 
loss. Cuttings of willow and cottonwood, which may be made from 
new wood in late winter or spring and ''heeled in" in a cellar until 
planting time, give good results, especially in permanently moist 

Time for setting trees. — It is advisable to plant windbreaks of 
both conifers and hardwoods in the spring. The severity of the cold, 
drying winds of winter, which injure growth that has not had time to 
mature fully, makes fall planting on the plains west of the Mississippi 
impracticable. Conifers may be successfully transplanted during any 
season of the year if care is taken, but the spring, as soon as danger of 

[Cir. 154] 


severe frost is past, is the best time, since the seedKngs will by winter 
be strong enough to resist the cold, drying winds. Broadleaf trees 
should always be transplanted between late March and early June. 

Methods of planting. — In planting evergreens care must be taken 
to prevent the drying out of the roots. When seedlings can not be 
planted at once, they should be removed from the packing case and 
*' heeled in'' in some shaded situation. If the packing case with the 
seedlings is placed in a cool cellar and the roots well moistened they 
will remain in good condition for several days, but if the tops become 
wet they will heat, become moldy, and die. Small evergreens should 
be carried to the planting site in baskets or pails containing a few 
inches of water. The roots may be kept moist with wet moss or sacks 
placed about them. The hole should be considerably larger than the 
root system and the seedlings should be set a little deeper than they 
stood in the nursery row. The soil must be packed firmly about the 

Spacing. — The pines and spruces should be planted in rows from 12 
to 16 feet apart, with the trees from 6 to 10 feet apart in the row. There 
should not be less than four rows in a windbreak. When the trees are 
from 8 to 12 years old the rows should be thinned, in order that all the 
trees may have sufficient moisture and room for full development. 
Corn may be grown between the rows for two or three years, which 
will provide cultivation for the trees and at the same time yield a profit. 
The hardwoods, such as silver maple, catalpa, honey locust, and ash, 
should be planted from 6 by 6 feet to 10 by 10 feet apart each w^ay. 
Thinnings should be begun when the trees are small poles and 
continued as long as there is danger of injury from overcrowding. 

Distance and direction from dwellings and orchards. — Many 
windbreaks have failed because they were placed too close to the home 
buildings and orchards, so that snow is piled in around the buildings 
and over the orchards. Windbreaks should be 5 or 6 rods from the 
buildings they are to protect, and there should be a space of 2 or 3 rods 
between the outer and inner rows of trees. 

Orchards should not be completely surrounded by -windbreaks, 
since lack of air drainage seems to increase the danger from disease and 
insects. The stillness of the air within such an inclosure makes it 
possible that a warm day may start the buds of fruit trees enough so 
that they will be killed by the frost which usually follows. The same 
stillness of air may, on the other hand, cause a lov/er temperature on a 
cold day or night, and create a ''frost pocket," so that there may be 
Idlling frosts within an orchard too completely surrounded by wind- 
breaks, when they do not occur outside. 

[Cir. 154] 


Diagram for proposed windbreak. — For average soil and mois- 
ture conditions in central Iowa, the following scheme for planting is 
suggested : 


40 +o 80 rods 





e-3 rods^ 




e-5rods-C J 

Russian olive 
Whi+e spruce 
White pme 
White spruce 
White' pine 

White pine 
Hardy catalpa 
White pine 
Hardy catalpa 

Fig. 1. — Diagram for proposed, windbreak, for average soil and moisture conditions in central Iowa. 

The outer rows should be 12 feet apart and the trees spaced 8 feet 
apart in the rows. The trees in the inner rows should be planted 6 by 
6 feet each way, and the catalpa should be removed when large enough 
for fence posts. 

Russian olive is suggested for the outside row because it is a hardy, 
low-growing tree, which succeeds under a \\4de range of soil and mois- 
ture conditions. It will protect the evergreen seedlings on the interior 
and will produce a medium grade of fence posts. Russian mulberry 
may be used in the same way in places where it is hardy. It is not 
advisable to plant such quick-growing trees as silver maple or boxelder 
v/ith the slower growing species, for they quickly overtop the more 
valuable trees and retard their growth by shade, and if they are not 
removed in time will be a detriment to the windbreak. 

Care of young and old trees in the windbreak. — A large pro- 
portion of the failures of windbreaks is due to a lack of cultivation and 
care during the first few years. The land upon wliich the planting is 
to be done should be well prepared. Growing corn on it for a year or 
two will put the soil in excellent condition. After the seedlings are 
planted the ground should be cultivated as long as it is possible to pass 
between the rows, usually from two to four years. Cultivation should 
be discontinued by August 1 each year, for it is likely to stimulate new 
growth which can not become mature before winter. Windbreaks 

[Cir. 154J 


require little or no pruning. The evergreens should be allowed to 
retain their lower branches, since they increase the efficiency of the 
break. When the lower branches begin to suffer from crowding, 
enough trees should be removed to permit complete development of 
the remaining ones. 

A number of successful windbreak plantings in different parts of 
the State are mentioned here to show that success has been attained in 
parts of the State which vary widely in soil, moisture, and situation: 

On the farm of F. F. Bakken, 5 miles west of Decorah, Winneshiek 
County, is an excellent grove of white pine 25 years old. The soil is a 
sandy loam, well suited to this pine. The trees are from 30 to 34 feet 
hign and from 4 to 12 inches in diameter. 

On the farm of W. Herring, Lincoln Township, Dallas County, there 
is a good windbreak of red cedar. The trees are 9 years old, and 
from 12 to 16 feet high and from 1 to 3 inches in diameter. Although 
the trees are making rapid growth on the rich black loam of this sec- 
tion, they are badly infested with cedar apple fungus. 

On rich prairie loam on the farm of W. A. Wilson, 5 miles northwest 
of Ainsworth, in Washington County, there are several rows of white 
pine which have made excellent growth. The trees are 35 years old, 
and range from 60 to 70 feet in height and from 9 to 16 inches in 

The Amana colony, in Iowa County, has several large groves of 
white pine and other pines which have proved veiy successful. The 
soil of this region is usually a rich sandy loam. 

Four miles east of Dougherty, Floyd County, on the farm of Henry 
Schafer, there is a windbreak of Scotch pine 10 years old, which has 
so far been very successful. Millet has been gro^^m between the 
rows to keep weeds down. 

On the C. E. Whiting estate, 24- miles north of Whiting, Monona 
County, is an excellent example of a black walnut windbreak. 


The rich prairie soil of Iowa is so valuable for the production of 
grain and stock that it wall not pay to plant large areas for com- 
mercial purposes. Forestry in the State will always be a matter of 
farm groves or native woodlots. It is probable that in the future, 
as frequently in the past, a large proportion of the grove plantings 
will be for the combined purposes of protection and the production 
of fuel, fence posts, repair material, and shade for stock. Hence, 
species should be selected which will most nearly meet these com- 
bined requirements. 

Location. — Usually those portions of the farm unsuited for other 
agricultural purposes have been utilized for tree growing, and this is 

[Cir. 154] 


right, for it is desirable to utilize completely or reclaim such waste 
portions. The owner frequently can not afford to plant any other 
part of the farm, for the better portions are necessary for its proper 
management. Good returns may be obtained by reforesting these 
rough lands, and caring for the plantations to keep out dense growths 
of weeds, shrubs, and scraggly trees. Large ranches and farms, 
however, can profitably devote several acres of good, rich land to 
trees for posts and farm repair material. There is no reason why 
large farms should not grow more than enough posts for their own 
fencing. But even on the best soils, unless the trees are carefully 
planted and protected, they will yield only a very small part of their 
possible returns. 

Species. — Where a considerable area is to be devoted to the pro- 
duction of posts, the best species to use are: Osage orange, which, 
however, is hardy in the southern half of the State only, hardy 
catalpa, European larch, honey locust, and green ash. Where very 
quick results are desired, wiilov/ may be successfully grown, but even 
the best quality of seasoned willow posts will not last more than 
from three to five years. Other slower-growing species make excel- 
lent posts, and it would be well to devote a small portion of the area 
to black walnut, coffeetree, white ash, slippery elm, red oak, Russian 
olive, and Russian mulberry. 

On bottomlands subject to overflow, and which are consequently 
not adapted to tillage, cottonwood and silver maple may be planted 
in groves for lumber. Excellent returns in lumber and dimension 
material have been obtained from plantations of these species. On 
dry soils cottonwood groves do not succeed. 

Planting. — Where Osage orange, hardy catalpa, Russian rnul- 
berry, or honey locust are planted on the heavy, rich loess soils of 
the State for the production of posts, they should be spaced 4 by 6 
or 6 by 6 feet, or if planted with a field crop like corn, they should be 
planted 8 by 8 feet each way. Such spacing will cause the young 
trees to make a rapid height growth, vv^hich is necessary for the pro- 
duction of the greatest number of good fence posts. On light sandy 
soil, the trees should be set at a greater distance apart, since there 
is not sufficient moisture to permit close planting. 

Seedlings of hardy catalpa, Osage orange, and honey locust have 
been successfully planted with corn in this State. A field is planted 
to corn in the usual way, and just as it is breaking through the ground 
a seedling is set in every other hill of every other row, in place of the 
corn. Two-thirds of the crop of corn is obtained in this way and 
the seedlings receive thorough cultivation and are protected by the 
stalks during the first year. Corn may also be planted the second 
year and a third of a crop obtained. In this way sufficient corn 

[Cir. 154] 


may be grown during these two years to pay for the rent of the land 
and for the cultivation. 

A very good example of this method of starting a catalpa grove is 
the 10-acre grove of George S. Waller, 2 miles south of Pioneer, Hum- 
boldt County. Twenty years ago Mr. Waller obtained hardy catalpa 
seed from Tennessee and raised seedlings which, when they were 
one year old, he put out with corn. The rows are about 8 feet apart 
each way and the cultivation, while the corn remained on the ground, 
gave the trees an exceptional start. Measurements show that the 
growth has been above the average throughout the twenty years. 
The trees are now froni 25 to 32 feet high and from 4 to 10 inches in 
diameter, and will average at least 3 good posts per tree. In 1903, 
400 posts were cut out of the grove as a thinning, and a careful esti- 
mate in 1905 showed that there remained on the 10 acres 6,146 trees. 
With 3 posts to a tree, the plantation now contains 18,438 posts. 
Besides this a large quantity of cordwood will be obtained when the 
final cut is made. If these posts are worth 15 cents each, the grove 
represents a value of $2,765.70. Add to this amount the returns 
from the 400 posts cut in 1903, at 15 cents each, and there is a total 
of $2,825.70, a good return from 10 acres in 20 years. During this 
period the grove has served as a windbreak for the home and farm 
buildings, and produced nearly all the fuel and repair material 
needed on the farm. 

The usual method of planting seedlings is to have two or five men 
work together. When there are two, one digs the holes with a spade 
or mattock and the second follows with the seedlings in a basket or 
pail. As explained before, the roots must be covered with wet moss 
or a sack and the trees should be set somewhat deeper than they 
stood in the nursery row. Where five work in a gang, two men dig 
the holes and three plant. On ordinary ground one man can plant 
from 400 to 700 trees per day. 

Growth and probable returns. — The probable rate of growth 
of any species and the returns under the most favorable conditions 
for growth can be stated only indefinitely. The data obtained 
during the investigation of the State's timber represents grov/th 
under unfavorable conditions. The groves studied had been, as a 
rule, pastured constantly, had not been thinned, and fires had run 
through most of them. Even under these conditions the returns 
have fully repaid the owners for their financial outlay and the occu- 
pation of the ground. 

The hardy catalpa, which has been planted extensively through- 
out Iowa, grows rapidly and produces a good grade of posts, repair 
material, and fuel. Fence posts reach a diameter of 4 or 5 inches in 
from six to nine years, according to the care and cultivation which 

[Cir. 154] 


is given. The most satisfactory results have been obtained with 
this tree by cutting the S-year-old seedlings back to the ground 
during the winter. The stumps send up a number of straight, clean 
shoots the following spring. All but one shoot should be removed 
within a few weeks or as soon as the best shoot can be selected. 
This principal shoot which is left will grow straight and clean to a 
height of from 8 to 14 feet the first season. By this process posts 
can be obtained as quickly as if the trees grew from seed without 
cutting back, and of a better quality. By cutting on short rotations, 
other crops of posts may be obtained from the stumps in a shorter 
time than the first crop. The Russian mulberry, Russian olive, and 
Osage orange may be treated in the same manner with satisfactory 

Posts from 3 to 5 inches in diameter may be grown from the 
Osage orange in from seven to eleven years; from honey locust in 
from eight to fourteen years; from Russian mulberry in from nine 
to fifteen years; from European larch in from nine to sixteen years; 
and from green ash in from seven to fourteen years. 

Some forms of the white willow will produce fence posts of ordi- 
nary size in from four to seven years. Nearly all of the slower- 
growing, more permanent species mentioned require from twelve 
to thirty years to form posts from 3 to 5 inches in diameter. The 
red oak and coffeetree are not planted as extensively as their value 
warrants. Both are hardy, fairly rapid in growth, and excellent 
for posts, repair material, and fuel; and each can be reproduced 
readily from seeds or stump sprouts. The coffeetree prefers moist 
situations, and the red oak well-drained slopes and uplands. 

The appended table shows the returns which have been obtained 
from various species under ordinary conditions of treatment. Typ- 
ical groves in different parts of the State were selected as the basis 
of the table. 

[Cir. 154] 

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