OCCASIONAL PAPER NO. 98 z.1'7 JABtJARI 17, 194'1 

SOUTHERN FOREST EXPERIMENT STATION 

E. L. Demmon, Director 

New Orleans, La. 

FIRST-YEAR SURVIVAL AND HEIGHT GROWTH OF 

COTTONWOOD PLANTATIONS AT STONEVILLE. MISS. 

By 

Henry Bull, Silviculturist 

and 

J. A. Putnam, Associate Forester 

Southern Forest Experiment Station 

In cooperation with 

Delta Experiment Station, Stoneville, Miss. 

The .aJor portion of this study was carried on in cooperation with the 

Mi •• is8ippilgricultural Experiment Station under the Cooperative Farm Forestry 

Act ot 1957. 
The Occasional Papers of the Southern Forest Experiment 

Station present information on current southern forestry problems under investigation at the station. In some cases, these 

contributions wore first presented as addr8sses to a limited 

group of people: and a3 Iloccasional papersll they can reach a 

much wider audience. In other cases, the;? are summaries of 

investigations prepared especially to give a report of the 

progress made in a particular field of research. In any case. 

the statements herein contained should be considered subject 

to correction or modification as further data are obtained. 

Note: Assistance in the prepanltion of these materials was furnished 

by the personnel of \'lorl~ Pro,~ects Administl'3.tion official project 65-2-64-'/4. 
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FIRST-YEAR SURVIVAL AND HEIGHT GROWTH OF 

COTTONWOOD PLANTATIONS AT STONEVILLE, MISS. 

By Henry Bull, Silviculturist 

and 

J. A. Putnam, Associate Forester 

Southern Forest Experiment Station 

In cooperation with 

Delta Experiment Station, Stoneville, Miss. 

Introduction 

Most cut-over forest land in the bottomland hardwood region does 

not need to be planted to obtain another stand of timber. Natural reproduction usually is satisfactory in amount, although often predominated by relatively undesirable species. cut-over areas that do need planting, however, are not uncommon. Very heavy cutting and repeated severe 

fires are largely responsible for this condition, but heavy overgrazing 

may also be a factor. Typical bottomland areas in need of planting support a scanty or negligible stand of low-grade and cull trees, and a very 

dense, tangled ground cover of weeds, brush, and vines. Since fast-growing trees are most likely to be successful in overcoming this severe competition, cottonwood is obviously an excellent prospect for planting. Fastgrowing trees may produce somewhat less desirable and less valuable wood 

for some purposes than trees with slower growth rates, but on bottomland 

planting sites it may be a case of fast-growing trees or failure. Cottonwoods will yield merchantable pulpwood, or later sawlogs, in a comparatively short period. They will also shade out the dense ground cover and thus 

facilitate the later establishment of more slowly growing tree species, 

some of which may be of greater intrinsic value. 

Besides general interest in the suitability of cottonwood for planting on most unstocked bottomland sites, there is special interest in the 

planting of cottonwood on Mississippi River batture lands (i.e., lands 

between the levee and the river) to replace mature cottonwood after logging. 

Cottonwood is always replaced by a number of other hardwood species after 

logging, and new cottonwood stands originate only on bare land deposited by 

a river or abandoned by farmers. Since the species that replace cottonwood 

frequently are much less valuable, it is desirable to obtain another stand 

of cottonwood either by measures that will favor natural reproduction or by 

planting. For either course, there is very little information available on 

suitable methods or probable results. 

Cottonwood Planting Experiments at Stoneville, Miss. 

Location and History. A cooperative forest research program was 

begun by the Southern Forest Experiment Station and the MisSissippi Agricultural Experiment Station in October 1939, with local headquarters at 
the Delta Experiment Station, Stoneville, Miss. The object of this program is to conduct research on important forestry problems in the bottomland hardwood region. A typical cut-over forest of 2,580 acres, owned 

by the State, is available at Stoneville for demonstration and research, 

and two research projects are now in progress on this forest. One project, 

conc~rped with improvement cuttings, has been reported in a previous paper.JI The other project, concerned with the planting of cottonwood, is 

reported here. 

Experimental plantations of cottonwood cuttings and seedlings were 

established at Stoneville between January 30 and April 26, 1940. The plantations were examined June 18 - 21, 1940, to determine the early survival, 

and October 4 - 12, 1940, to determine the first-year survival and height 

growth. A report on the June examination was made in an earlier publication.~ The present paper is a report on the October examination. Results 

obtained from the plantings of hybrid poplars are inconclusive thus far and 

are not further discussed in this report. 

Purpose. ~he cottonwood planting study was designed to determine 

(1) whether cuttings or seedlings make the better planting stock, and (2) 

the effects of different planting sites, dates of planting, depths of 

planting and lengths of cuttings, and top-pruning treatments of seedlings. 

Supplementary information also was obtained on the characteristics of the 

most successful cuttings and seedlings, the effect of a single partial release from competition, the effect of using a rabbit repellent, and the 

growth of cuttings in the nursery. 

There have been few previous studies of forest planting in the Delta; 

hence there was little background of experience for the present study. 

Valuable advice was obtained, however, from Mr. R. D. Stevens, of the Department of Horticulture and Forestry, University of Arkansas, who had recently 

made experimental cottonwood plantings in the Delta region of Arkansas. 

Planting Sites. Two experimental plantations were established. One 

plantation occupies a. well-drained "flat" that supported bottomland red oak, 

over cup oak, water hickory (bitter pecan), American elm, and other bottomland species. The other plantation is divided by a shallow slough into a 

"ridge" and a shallow swamp. The ridge site is higher than the flat, and 

once supported such species as redgu~ and water oak. The swamp supported 

baldcypress, waterlocust, swamp privet,~ and other swamp species, and was 

i7 Putnam, J. A., and Henry Bull. Improvement cuttings in the bottomland 

hardwood forests of Mississippi. Occasional Paper No. 95. Sou. For. Expt. 

Sta. Oct. 22, 1940. 

~ Bull, Henry, and J. A. Putnam. Early survival of cottonwood and hybrid 

poplar plantations at Stoneville, Miss. Occasional Paper No. 94. Sou. For. 

Expt. Sta. Oct. 4, 1940. Y The common name recently accepted by the Forest Service for Liquidambar 

styraciflua is sweetgum. 

~Similarly, Forestiera acuminata is common adelia. 

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intermittently under water or waterlogged throughout the planting period. 

The flat is too wet in the spring for profitable agricultural use except 

in unusually dry years. The ridge is fair to good farm land, but the 

area is small and relatively inaccessible. The swamp is entirely unfit 

for farming, even though there is a large drainage canal within a quartermile. 

To provide more uniform conditions for experimental purposes, and 

to facilitate the planting and later examinations, the largely low-grade 

and cull trees on the flat were girdled, and the sparse stand of similar 

trees on the other two sites was clear cut. On the flat the planting 

was done in narrow lanes cut through the dense brush, weeds, and vines 

wit.h "Kaiser" blades (large ditch-bank blades or brush hooks). On the 

other two sites the entire planting area was cleared with Kaiser blades 

after the trees were removed. The brush, weeds, and vines sprouted 

vigorously in the spring and were 2 to 5 feet high in mid-June. 

All three sites have heavy clay soils, whereas natural stands of 

cottonwood along river margins usually are on very much lighter soils 

that range from very fine sands to fine sandy loams. Cot.tonwood has been 

observed to grow well on almost any soil type in the Delta when once established, but the extent to which soil type affects establishment is no~ 

known. The most obvious reason why cottonwood usually is not abundant except along river margins is that moist, bare soils are seldom found elsewhere. Cottonwood seed is exceptionally light, fluffy, and perishable; 

it cannot reach the ground at all if vegetation is present, and after 

reaching the ground it must have continuously plentiful moisture to germinate and grow. Heavy clay soils usually do not occur along river margins, and seldom are moist and bare at. the same time on cut-over lands. 

A few cottonwood cuttings were planted in Deer Creek fine sandy loa.m in 

the horticultural nursery at the Delta Experiment Station in March 1940, 

and although their survival was only slightly better than that of cuttings 

on the heavy clay of the cut-over land, their height growth was some 8 to 

15 times greater. Since the cuttings in the nursery were cultivated several 

times and had no competition from other vegetation, the effect of soil type 

alone cannot be evaluated. 

Since there is no conclusive evidence as to the relative advantages 

of heavy clay soils and much lighter soils in enabling cottonwood cuttings 

and seedlings to root themselves, the application of the results of the 

present study to much lighter soils is not known. It is thought, however, 

that the results would be at least as good--and probably better in an abnormal year like 1940--on lighter soils that contain much silt or fine 

sand and retain considerable moisture well into the summer. Results probably would be poorer on coarse sands that dry out rapidly during the summer. 

f1anting Stock and Methods. Cuttings from native cottonwood 

(Populus deltoides virginiana) were taken with pruning shears from vigorous 1-year-01d shoots in the middle and upper parts of freshly felled 

trees in stands between the levee and the Mississippi River near Greenville, Miss. The trees were mostly 2 to 8 inches in di~~eter, al~~ough 

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a few were as large as 12 inches in diameter. "Fresh" cuttings were 

planted within 2 to 4 days after they were obtained, being heeled into 

the ground or stored in shallow water in the meantime. "Stored" cuttings were kept in cold storage at a temperature of about 350 F. between 

the time of preparation (March 4) and that of planting. Four different 

lengths of cuttings, two depths of planting for each length of cutting, 

and three dates of planting were tested with fresh cuttings. A single 

length of cutting and depth of planting at three ,different planting 

dates were tested with stored cuttings. 

On the flat, the planting was done from January 30 to February 2, 

when cottonwood buds were completely dormant. On the other two sites the 

plantings included one while the cottonwood buds were still dormant 

(March 6 .- 8 and 11), one at the time the buds were beginning to open 

(March 25 - 27), and two after the buds had opened in the woods (April 

15 - 17 and 26). An cuttings were set in holes made with cylindrical 

planting bars. Bars of various diameters from 1/4 to 7/8 inch were used, 

depending on the diameters of the cuttings. An effort was made to obtain 

a tight fit for each cutting, and contact between the base of each cutting 

and the bot tom of the hole. 

I Cottonwood seedlings were obtained from nearby ditches and borrow 

pitaS for planting on the flat, and from stands between the levee and the 

Mississippi River for the other two sites. Seedlings 1; to 7 feet high 

and mostly 2 years old were selected and pulled up without any digging. 

They were then planted, after just enough trimming of the roots to permit 

placing in holes made with the same planting bars used for the cuttings. 

The tops of some seedlings were left unpruned, while others were cut back 

to 2, 4, or 18 - 24 inches. Both fresh and stored seedlings were planted, 

the former at the same dates as the cuttings, but the latter on April 26 

only. 

Spacings of both 6 x 6 and 8 x 8 feet were used, but the results 

to date are most probably not affected by spacing. 

Special Observations and Treatments. Certain obvious physical characteristics and measurements of the cuttings and seedlings planted on the 

flat were recorded for each plant, since it seemed likely that some item 

of appearance or size might be closely related to survival and growth. The 

data and the results are discussed in sections 3 and 5 under "Results." 

After completing the planting on the flat, half of each test was 

treated with a rabbit repellent as a precaution against possible damage. 

The comppsition of the repellent and the interesting but unexpected results produced are discussed iIi section 12 under "Results." 

In early June, the competing vegetation was so dense and tall that 

it was thought possible that certain tests might prove successful only if 

the cottonwood plants were at least temporarily and partially released from 

this severe competition. Half of each test on each site was therefore released. The character of the release and the results obtained are discussed 

in section 7 under "Results." Comparisons of released and unreleased stock 

are also mentioned in other sections. 37 Source of material for levees or roads. 

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Unusual Growing Conditions and Insect Damage. At Stoneville the 

winter of 1939-40 was exceptionally cold and dry. The swamp was not 

flooded at all during this season immediately preceding planting. Conditions suitable for plant growth in the spring came into being about 3 

weeks later than usual; it was unusually cool and wet until well into 

June, and unusually wet for a month longer. The ground remained cold 

and soggy long after the cottonwoods had fully developed leaves, and heavy 

rains flooded the swamp three times during March and April. All existing 

local records were broken by a very late killing frost, on April 15, and 

by heavy rainfall during late June and early July that flooded parts of 

the swamp to a maximum depth of 5 feet and resulted in standing water 

over most of the swam.p for a period of about 10 days. Rains and floods 

of this nature are c~~on in the region in January, but previously unrecorded in July. From the middle of July until November there was very 

little rain, and temperatures were normal or above normal. It is impossible to say exactly what effect these very unusual conditions had on 

the survival of the experimental plantings, but it seems certain that 

the conditions were unfavorable, especially to cuttings, because of their 

lack of roots when planted. 

Insect damage was unusually widespread during the growing season, 

and at least three species of insects had a part in it. Poplar beetles 

were prevalent very early in the spring, then disappeared in May after 

defoliating relatively few plants. These beetles probably caused no 

actual mortality, but helped to weaken many individual plants. Later in 

the summer s.all, gray, woolly caterpillars became very numerous and de~ 

foliated a large proportion of the plantings. These caterpillars, which 

seemed to feed only on cottonwood and willow, defoliated many trees more 

than 50 feet tall. Local residents do not recall any previous attack of 

similar severity. In the plantations the caterpillars seemed to prefer 

the tallest, most vigorous, and most conspicuous plants and completely defoliated most of them. This injury occurred late in the season and it is 

doubtful that it caused any mortality. Grasshoppers caused considerable 

damage by chewing off patches and sometimes complete bands of bark. Such 

scars might have been mistakenly ascribed to mice or rabbits, except that 

they were usually found at heights to which these animals could not reach. 

Grasshoppers killed a few apparently well-rooted plants by girdling them, 

and caused much additional damage by chewing out terminal buds and girdling 

terminal shoots, which results in forked or crooked trees. 

Analysis or Data 

The plantations were planned and arranged in the field according 

to modern statistical techniques of replication and randomization, with 

four blocks on each site. A detailed analysis of variance to determine 

the statistical significance of the various survival percentages and 

average heights could be made, but is considered unnecessary. The study 

is exploratory and the main interest is in the larger, consistent differences that hardly need statistical measures of significance. Horeover, 

some small or inconsistent differences need further testing on a larger 

scale or in other years regardless of whether or not they are statistically 

significant in the present study. The results discussed below are based 

on a st~ of the size and consistency of survival percentages and average 

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heights, and involved many separate tabulations to bring out desired comparisons. Even large differences would of course have doubtful significance in 

the absence of proper replication and randomization; hence, the field arrangement has proved indispensable. 

Results 

For each test, the number planted and the percentages alive in June 

and in October are recorded in tables 1, 2, and 3. A complete examination 

was made in June, but in October the tests that it was thought would show 

less than 10 percent survival were not examined. The tests not completely 

examined in October are considered too poor for further study. Identification of the tests showing these unsatisfactory results was made from the 

records of the June examination, supplemented b.Y an October examination of 

representative borderline cases. Table 4 lists the more successful planting stock for each site and planting date. 

Table 1.--8ummary of survival in June and in October 1940 of all 

cottonwood plantings made January 30 - February 2, 1940 

Site: flat 

Length Depth Alive Alive in 

October Stock Class of stock of of in 

Not .1 Released planted cutting planting June released 

- Inches - - Percent - - Number 

Fresh cuttinID 

Termina 1 12 9 57 3 12 44 

Nonterminal 12 9 45 5 20 44 

Terminal 16 12 51 14 28 43 

Nonterminal 16 12 50 11 50 44 

Terminal 20 .15 47 16 35 43 

Nonterminal 20 15 53 19 44 43 

Fresh seedlings: 

Top cut back to 

2 inches 84 41 41 44 

Not cut back 68 18 58 44 

JJ A terminal cutting is one made from the end of a shoot, including the 

last or terminal bud. 

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1'ab1e 2.-8wnmary ot survival in June and in October 1940, of unrDiY8ed 

auttcllwood anttlnp pI_ted Jllirch..6 - April 26, 194 

Kind Depth Date of p1antin~ and dates of examination Cuttings 

of ot y Mar. 6-8 Mar.25-Z7 Anr.15-17 A'Dri1 26 planted 

cut- Length p1ant- 8ite June\oct. June\oct. June\oct. June\oct. at each 

tings ing date 

- Inches - - - - - - - - - Percent - - - - - - - - --

lumber 

Fresh 10 6 R 17 18 3 99-100 

10 6 S 28 35 19 97-99 

10 8 R 35 9 44 9 ° 100 

10 8 8 30 42- 4 '85-89 

20 12 R 54 23 36 19 6 99-100 

20 12 S 55 ° 35 3 99-100 

20 16 R 64 26 55 51 7 100 

20 16 S 26 0 29 0 3 97-100 

40 15 R 33 18 17 1 100 

40 15 S 57 7 30 0 6 99-100 

40 20 R 53 24 'Z7 15 1 100 

40 20 S 36 3 23 0 15 100 

60 18 R 24 0 10 2 50 

60 18 S 40 18 14 6 50 

60 24 R 32 6 16 4 2 49-50 

60 24 S 38 22 8 32 12 49-50 

Stored. 20 16 R 71 Z7 55 IS 55 2 100 

20 16 S 35 0 55 2 5 0 100 

1 In this and subsequent tables, a short dash (-) in a data column indicates 

that no data were recorded. See explanation under "Results, II page 6. 

y R = ridge; S = swamp. 

Table 5.-8ummarl of survival in June and in October 19~01 of unreleased eotton- woo~ seedlings J21anted March 11 - AJ2ril 26 1 19~0 

lind Length Date of tl1ant1ruz: and dates of exam.inatioa. Seedlings of after S1teY' Mar. 11 Mar.25-27 A'Dr.15-17 April 26 planted 

seed- cutting Juneloct. Juneloct. JUlle\oct. June I oct. at each 

lings back date 

Inche. - - - - - - - - Percent - - - - - - - - Rwnber 

Fresh .4 R 88 44 92 18 8 12-25 

4 8 80 24 73 0 25 12 11-25 

18 - 24 R 80 24 69 55 15 13-25 

18 - 24 8 88 64 85 68 15 ° 13-25 

n.c.b.V fl 64 9 88 52' 4 25-50 

n.e.b. S 46 26 52 44 8 25-50 

Stored 4 R 83 55 12 

4 S 92 18 12 

18 - 24 R 69 0 15 

18 - 24 S 100 40 IS 

n.c.b. R 48 ° 25 

n.c.b. S 84 42 25 

~ R = ridge; S = swamp. 

Not cut back. 

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Site 

Ridge Fresh 

Fresh 

Fresh 

Fresh 

Fresh 

Fresh 

Swamp Fresh 

Fresh 

Fresh 

Fresh 

Fresh 

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Table 4.--Plantins stock having best first-year survival, grouped accordinc to site 

and planting date. All plantings having at least 18 percent 

survival are listed. 

Planted March 6 - 8 and 11 Planted March 25 - 27 Planted April 26 

Survival Survival Sunival 

Kind of stocIJ./ Not Kind of stocJ&;!/ Not Kind of stockY Not 

ra- Re- re- Re- re- Released leased leased le~sed leased leased 

• Percent Percent Percent 

sdlgs. 411 44 60 Fresh sdlgs. Uncut 52 44 Stored sdlgs. 4" 55 55 

ctgs. 20 - 1611 26 26 Fresh sdlgs. 2011 35 41 

sdlgs. 20" 24 64 Fresh ctgs. 20 - 16" 51 59 

ctgs. 40 - 20" 24 58 Stored ctgs. 20 - 16" 27 27 

ctgs. 20 - 12" 25 31 Fresh ctgs. 20 - 12" 19 25 

ctgs. 40 - 1511 18 20 Fresh sdlgs. 4" 18 61 

sdlgs. 20" 64 80 Fresh sdlgs. 20" 68 70 Stored sdlgs.Uncut 42 51 

sdlgs. Uncut 26 42 Fresh sdlgs. Uncut 44 52 Stored sdlgs. 20" 40 75 

sdlgs. 411 24 40 

ctgs. 60 - 2411 25 25 

ctgs. 60 - 1811 18 26 

Planted January &0 - Pebruarl 2 

Flat Fresh sdlgs. 2" 41 41 

Fresh ctgs. NT, 20 - 15" 19 44 

Fresh sdlgs. Uncut 18 58 

11 The figures following "sdlgs" (seedlings) represent the height in inches to which they were cut back 

atter planting. The figures following "ctgs" (cuttings) represent the length and the depth of planting, 

respectively, each in inches. NT = Nonterminal. 
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The principal results contained in the foregoing tables and in other 

data obtained in the study are discussed below in short, numbered sections. 

This method of presentation seems desirable in view of the large number of 

variables to be considered, and facilitates reference to the different topics. 

Survival percentages mentioned below are for unreleased plants unless specifically noted otherwise. 

1. Seedlings vs. cuttings. In general, seedlings showed much higher 

survival than cuttings. Table 5 gives the best individual survival percentages for each class of stock for the different sites. 

Table 5.--Comparison of best results for seedlings and cuttings, in 

survival percent, classified according to planting site 

Site Stored stock 

Seedlings Cuttings 

Ridge 52 51 55 27 

Flat 41 19 

Swamp 68 22 42 2 

2. Time of planting. Plantings of fresh seedlings during the dormant 

period, and at the time cottonwood buds were beginning to open, resulted in 

approximately the same survival. Fresh cuttings, however, showed slightly 

better survival when planted during the dormant period than when planted at 

the time the buds were beginning to open. The two different dates of planting within the dormant period gave equally good results for both classes of 

stock. In marked contrast, plantings of fresh stock 2 to 5 weeks after the 

buds had opened were complete or almost complete failures. 

Planted at the time the buds were beginning to open, fresh cuttings 

showed slightly higher survival than stored dormant cuttings of the same 

depth of planting and length. The fresh cuttings planted 2 to 5 weeks after 

the buds opened, however, had slightly lower survival. The stored cuttings 

that were planted at the time the buds were beginning to open showed best survival, those planted 2 to 5 weeks later poorer survival, and those planted 

4 weeks later poorest survival. 

The data indicate clearly that planting should be done during the dormant period, not later than the time the buds begin to open. If for any reason planting must be done later, stored dormant stock is preferable and should 

be planted as early as possible in the growing season. 

5. Characteristics of the most successful seedling stock. The length 

of the top and the length of the roots at the time of planting were measured 

and recorded for the 88 seedlings planted on the flat. Records also were 

kept of the seedlings cut back to about 2 inches soon after planting. Root 

lengths varied from 3 to 14 inches and averaged 8 inches. The original top 

lengths varied from 19 to 82 inches and averaged 45 inches. The seedlings 

planted on the other two sites were not measured, but probably averaged about 

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4 inches more in root length and about 10 inches more in original top length. 

Their survival was somewhat better than that of the seedlings on the flat, 

indicating that the larger seedlings make better planting stock. Analysis 

ef data for the measured seedlings indicates that the stock with the longer 

roots showed distinctly the better survival regardless of the length of the 

original top and regardless of whether or not the top was cut back. The 

20 seedlings with roots at least 10 inches long showed 55 percent survival, 

whereas the 68 seedlings with shorter roots showed only 37 percent survival. 

Root length was by far the most important single factor measured. 

4. Cutting back of seedlings vs. no cutting back. Table 6 shows how 

the effect of cutting back seedlings immediately after planting varied with 

the site and with the time of planting. 

Table 6.--Percentages of survival in October for unreleased seedlings, 

classified according to cutting-back treatment. site, 

and time of planting 

Time Cut back Cut back Not 

Site of to to 18-24 cut 

planting1/ 2-4 inches inches back 

Ridge Complete dormancy 44 24 9 

Buds open~ 18 35 52 

Leaves ou 2 35 0 0 

Swamp Complete dormancy 24 64 26 

Buds open!]j 0 68 44 

Leaves au 2 18 40 42 

lat Com lete dormanc 41 18 

1 Phrases in this column refer to condition of nearby large cottonwoods. 

~ Stored stock was used at this time. 

In the swamp, seedlings cut back to 18 - 24 inches generally showed 

hi~~est survival, and those cut back to 4 inches lowest survival. On the 

rid,e, however, highest survival was obtained either with seedlings cut back 

to 4 inches, or with seedlings not cut back, depending on the time of planting. These results indicate that cutting back improves survival when the 

plant cannot begin growth immediately, or when the supply of moisture is not 

abundant. 

5. Characteristics of the most successful cuttings. The kind (terminal or nonterminal), diameter class, and numbers of large and of small 

buds were recorded for each of the 264 cuttings planted on the flat. Terminal cuttings (those made from the ends of shoots, including the last or 

terminal buds) showed the same survival as nonterminal cuttings where there 

was no release from competition, but consistently lower survival where released. This is shown in table 7, adapted from table 1 . 

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Table 7.--Perceptases of survival in October for fresh cuttings PlaQte4 9D 

the flat. clas!ified bY release tre§tment and kind of 'took 

l:ind 01 af:oclC lof: releasea lleleasiC! 

12-inch cuttings: 

Terminal 5 12 

Bontermina1 5 20 

16-inch cuttings: 

Terminal 14 28 

Nonterminal 11 50 

20-inch cuttings: 

Terminal 16 55 

Bonterminal 19 44 

All lengths: 

Terminal 12 21 

Ronterminal 12 56 

The table also shows that survival increased with length regardless 

of whether or not the cuttings were released. On the other two sites, the 

best lengths were found to be 20 and 40 inches on the ridge, and 60 inches 

in the swamp (see next section). 

For a given length and kind of cutting (terminal or nonterminal), diameter or thickness apparently did not affect survival. The numbers of large 

and of small buds an a cutting showed no strong or consistent relationship to 

survival. 

6. Depth of planting and length of cuttings in relation to site. 

Table 8 shows the best survival percentages for diffarent depths of planting 

and lengths of fresh cuttings on the ridge and in the swamp. 

Table 8.--Best October survival percentages for fresh cuttings of various 

lengths, grouped by site and mode of planting 

Length or cutting 

(inches) 

10 0 9 0 0 

20 25 51 0 0 

40 18 24 7 :5 

60 0 6 18 22 

It 1s evident that 20- and 40-inch cuttings are best on the ridge, 

and that 60-inch cuttings are best in the swamp. The failure of short cuttings in the swamp probably is due largely to the smothering competition ot 

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dense weeds at the tiM the cuttings were tr)riq to get rooted. Seedlings 

in the awaap, even though they had roots to start with, showed their poorest 

survi val when most severely cut back .• 

Relatively deep planting produced the better results on the ridge, 

but in the SwaMp the effect of different depths of planting is indefinite • 

7. !trect of a single partial release from competition in June. A 

single partial release from competition was accomplished by "chopping" away 

competing vegetation around each plant with a cotton-chopping hoe to a 

radius of about 1-1/2 feet in half of the rows devoted to each separate test. 

Table 9.--Average survival and total height at released stock 

~ressed as perc en taReS of the averages t:: unreleased stockl/ 

Survival 'fotal height 

Kind of stock Ridge 1 Flat I SwaMp Ridge I Fla t I Swamp 

Fresh cuttings: 

10 - 12 inches long 150 438 100 86 140 

16 - 20 " " 121 256 (2 to 0) 144 130 

40 " n 112 164 109 82 

60 " " 126 100 140 86 

Stored cuttings: 

20 inehes long 162 to to 2) 143 

Fresh seedlings z 

Cut back to 4 inches 167 102 238 104 114 122 

Cut back to 18 - 24 in. 203 117 IlS 110 

Not cut back 143 335 140 100 108 99 

Stored seedlings: 

Cut back to 4 inches 100 (0 to 20) 105 

Cut back to 18 - 24 in. (20 to 0) 187 lSS 

Not cut back (33 to 0) 122 104 17 When one survival percentage is 0 and the other is 1 or more, the latter is 

infinitely greater. In such cases, to give a better picture of the actual comperisan, both survival percentages are given; e.g., (20 to 0) means that the 

released stock has the better survival: 20 percent va. 0 percent for the unreleased stock. 

It is evident that partially released stock of all classes generally 

surpassed unreleased stock in both survival and total height. In general, 

the partial release was more effective in increasing survival than in increasing total height. 

8. Total heights attained in the first growin~ season. A brief summary 

of the average total heights attained in the first growing season is given in 

table 10, based an fresh stock, not released. 

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Table 10.-Average total heis!,!t of unreleased stock in 

October z in inches 

!rind of stock Ridge I Flat Swamp 

Cuttings: 

10 - 12 inches long 7 5 0 

16 .- 20 inches long 9 8 0 

40 " " 25 56 

60 tI " 50 57 

. Seedlings: 

Cut back to 2 - 4 inches 24 22 49 

Cut back to 18 - 24 inches 38 61 

Not cut back 44 25 78 

The effect of release on total heigbt is sbown in the preceding 

section. Storage and date of planting had relatively little effect on 

total height. 

9. Form of surviving cuttings and seedlings. In general, the form 

or straightness of surv~v~ng cuttings and seedlings is satisfactory frOM 

the standpoint of future sawlog or pulpwood production. The stock on the 

ridge is especially good in this respect, although a few trees there may 

not straighten satisfactorily as they grow larger. In the swamp, however, 

about one-third of the plants have a definitely unsatisfactory form. In 

most cases, poor form is caused by interference frOB the extremely heavy 

ground cover of shrubs, weeds, and vines. Buckvine, the worst offender, 

has frequently caught and pulled down the young cottonwoods and forced 

th. to grow almost horizontally through entangling vegetation. In some 

cases the surrounding vegetation has nothing to do with the poor form; 

the young cottonwoods simply start their new growth above a very crooked 

or leaning portion of the plant. Grasshoppers, and possibly other insects, also contribute to poor form by eating the terminal buds and by 

girdling the main shoots. Girdling kills the trees if no new sprouts are 

put out below the girdle. 

Since in most cases the trees with a very unsatisfactory form will 

have A relatively low commercial value in the future, and in most cases 

will never even reach commercial size, these trees should be cut back at 

or very close to the ground during winter or early spring, and thus forced 

to sprout again. Straight sprouts-but perhaps multiple rather than single sprouts-should result from this treatment. Al though the new sprouts 

may again be caught and deformed by vines, the danger is not so great as 

before, since the new sprouts ~ill have the advantage of an established root 

system and probably will outgrow the vines. The need for cutting back ~bout 

one-third of all stock planted in the swamp makes an extra expense to charge 

against this site, but it may well be counterbalanced by better survival, 

better growth, and the probability that in the swamp a planted stand has 

greater advantages over a possible natural stand than it would have on other 

sites. 

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, 

10. Differences in survival between ridge and swamp plantings. Of 

+.he 8 plantings of cuttings with survivals of 18 percent or better in 

October, 6 are on the ridge and only 2 are in the swamp. Of the l~ plantings of seedlings with the same minimum survival, 6 are on the ridge and 

7 are in the swamp, with the 2 highest survival percentages in the swamp. 

Cuttings evidently are far better adapted to the ridge, whereas seedlings 

are not so sensitive to site but do slightly better in the swamp. 

These facts, and several others already discussed concerning depth 

of planting and length above ground, indicate that survival on the ridge 

depends large17 on having a considerable length in the ground (to obtain 

sufficient moisture), and only a comparatively short length above ground 

(so that drying out will not be excessive). The poor survival of 10-inch 

cuttings on the ridge, for example, is probably due largely to the short 

length in the ground. Survival in the swamp apparently depends largely on 

having a considerable length above ground so that the new shoots can begin 

growth at a level close to or above the tops of the exceptionally dense 

competing vegetation. The plentiful or excessive moisture in the swamp 

presumably makes it unnecessary to plant deeply or to'leave only a short 

length above ground. In addition to heavy competition, another condition 

in the swamp that makes necessary a long length above ground is the frequent presence of standing water deep enough to submerge and kill short 

lengths. 

11. Mortality between June and October, and factors affecting it. 

In every test the survival recorded in October is lower than the survival 

recorded in June, and in most cases it is much lower (see tables 2 and 3). 

The plantings that ranked at or near the top in June usually ranked at or 

near the top in October also, but there are a rew striking exceptions, all 

in the swamp tests. For example, fresh 20-inch cuttings planted 12 inches 

deep in early March dropped from 55 to 0 percent survival; fresh seedlings 

planted in late March and cut back to 4 inches dropped from 7~ to 0 percent 

survival; and stored seedlings planted in late April and cut back to 4 

inches dropped from 92 to 18 percent survival. It is notable that all of 

these plantings are of relatively short lengths above the ground in the 

s~. 

The plantings showing good results both in June and in October generally had from one-half to two-thirds as high survival in October as at 

the earlier date. Seedlings as a rule showed lower losses than cuttings 

during the SUMMer, although on the ridge the best plantings of each class 

of stock show virtually the same losses. Stored stock showed considerably 

heavier losses during the summer than fresh stock. With respect to sites, 

the beet plantings of both seedlings and cuttings usually showed smaller 

10SS88 during the summer in the swamp than on the ridge, whereas the poorer plantings showed exactly the opposite result. Losses between June and 

October seeaed to have no appreciable relation to date of planting. 

In Most cases, cuttings that were alive in June but dead in October 

either had no roots or very meager roots, a fact revealed by pulling up 

many of the. in October. Similarly, most of the seedlings that died during 

the summer probably had no live roots in June. In the swamp, heavy vegetation and late floods probably were largely responsible for killing the 

tops of Many plants that had leafed out in June, weakening whatever root 

growth had started. It iw possible that most of the plants that were leafed 

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• 

out in June had little or no root formation, and that roots did not develop 

during the summer except under favorable conditions of soil moisture, retention of moisture in the tops, and competition with other vegetation . 

12. Effect of rabbit repellent. The rabbit repellent was prepared 

b.1 stirring S pounds of liquid asphalt paint into 3-1/3 quarts of water, 

adding 3-1/3 pounds of copper carbonate, and then enough water to make up 

4 gallons. This was sprayed or painted on the planting stock in 2 of the 

4 blocks on the flat, and produced an unexpected result. It proved to be 

unnecessary to protect the plantings from rabbits, since no rabbit damage 

was noted later in the untreated blocks. Survival data for treated stock, 

however, expressed as percentages of the survival ot untreated stock on the 

same site, were as follows: 

Cuttings 

Seedlings 

~ October 

116 

112 

157 

70 

It is thought that the differences in favor of the treated cuttings 

are the result of conservation of moisture brought about by the repellent 

coating. Probably the asphalt in the repellent was largely responsible for 

this action. The fact that the seedlings eventually did not survive better 

in the treated plots fits well into this theory only if it is assumed that 

seedlings are much less or not at all in need of protection from loss of 

moisture. This is not unlikely, however, since seedlings benefit from having 

roots when planted, and tops that generally seem to be less succulent and to 

have tighter bark than cuttings. For these reasons, seedlings probably are 

more capable of maintaining adequate moisture • 

IS. Possibility of improved results through aelection at stock. The 

results discussed in this paper were obtained without careful selection of 

stock. In the case of cuttings, material was obtained at random from l-yearold shoots from the upper parts of the crowns of well-developed saplings and 

small trees without any discrimination other than to discard a few very crooked, 

weak, or injured shoots. In the case of seedlings, 1- and 2-year-old plants 

were taken at random, again discarding only very crooked, weak, or injured 

seedlings. In the use of either cuttings or seedlings, however, especially 

cuttings, it is probable that careful selection of stock of only a certain appearance or character, or from trees of only a certain appearance or character, 

will greatly improve survival and growth. At present there is no basis for 

such selection, but studies designed to explore this field will be commenced 

soon at Stoneville. 

Conclusions and Recommendations 

Based on results obtained solely on clay soils and in a single, abnormal 

growing season, conclusions are necessarily tentative and may be modified b,y 

further studies. In view of the demand for informatian that can be put to immediate practical use, however, it is desirable to present conclusions and recommendations at this time. 

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~. '< ~'-~.;.~~ 

'f 

Prosent indications arc ths.t wild I!ottonwood seedlings (wildings) 

are better than cuttings for planting stock. Seodlings should be obtained 

and planted before the buds open in the spr~ng: or obtained early and held ~. in cold storage if for tl1ly I'ea.son the planting can be done only a.fter growth 

has startod.. Fresh, dormant stock planted very soon after pulling is praferable, aDd it must not be ~llowed to dry out before planting. Seedlings 

M7 be obtained frOM natural stands close to the iUssissippi or other large 

rivers, or in borrow pits ~nd ditches. In swamps and low flats the seedlin,s should be cut back to about 18 - 24 inches at the time of planting. 

, 

On rids_s or high flats the seedlings should be cut back to about 4 inches 

it the planting is done at least 2 weeks in advance of the opening of the 

buds, or if the stock has been stored and is planted after growth has 

started in the woods; otherwise the seedlings should not be cut back. The 

seedlings should be approximately 2 years old, or about 4 to 7 feet high, 

aDd the roots should be at least 10 inches long. 

In view of the probable survival percentages of about 50 percent 

on ridces and 70 percent in swamps for the first year, a spacing of about 

6 x 6 feet seems more suitable than wider spacings. At least one partial 

release trom competition in June appears desirable but not essential. 

During the dormant period following the first growing season, crooked and 

deformed seedlings and those interfered with by vines should be cut back 

just above the ground. Since total heights will probab17 average about 

3 feet on ridges and 5 feet in swamps, it should Dot be difficult to find 

the saedliDgs that will benefit from cutting back. 

It seedlings cannot be obtained , cuttings ma7 be used. On ridges 

or high nats, cuttings should be 20 inches long and planted 16 inches deep. 

In &waaps and low flats, cuttings should be 60 inches long and planted 24 

inches deep. The stock should be obtained and planted before the buds open 

in the spring, and JRWJt not be allowed to dry out before planting. Cuttings 

that do not include the terminal bud are preferable. Recommendations conc8l'lling spacing, release trom competition, and the -cutting back of crooked 

plants after the first growing season are the same as for seedlings. 

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