No. 111 

1960 

OBSERVATIONS ON A HYBRID POPLAR 

TEST PLANTING IN WEST VIRGINIA 

Hybrid poplars, crosses between European and American 

Aigeiros poplars, have been grown in Europe for about 200 

years. The rapid growth and high productivity of some of 

these hybrids on sites to which they are adapted has stimulated interest in poplar growing in this country. And demand 

for these poplars is developing in many parts of the United 

States. 1 

As part of a region-wide test of the Northeastern 

Station's hybrids, dormant cuttings from 50 hybrid poplar 

clones were out-planted in 1951 in four replicate plots in 

north-central West Virginia: two in the U. S. Forest Service 

Nursery at Parsons and two in an old field on the Horseshoe 

Run bottom, 8 miles northeast of Parsons. 

The plantings were on alluvial soils derived from 

acid sandstones and shales. Pope gravelly silt .loam at 

Horseshoe Run is a well-drained soil. The Philo sandy loam 

at the Parsons nursery is a moderately well-drained alluvial 

soil with evidence of impeded drainage at a depth of 2 feet. 

Both soils have a pH of about 5.5. 

Each plot consisted of a square of 16 cuttings planted at a spacing of 4 x 4 feet. The sites were plowed prior 

to planting, and they were cultivated three times the first 

growing season. No further care was given these plantings. 

The close spacing, without thinning, may have slowed the 

growth rate. Therefore, heights reported here are probably 

not so great as those that might have developed under intensive management. 

l~chreiner, Emst J. Production of poplar timber in Furope and its signifi- cance and application in the United States. U. S. Dept. Agr. Agr. Handbook 150. 

124 pp., illus. 1959. 
Table 1.--Clone numbers and parentage of material used in the Parsons Nursery 

and Horseshoe Run hybrid poplar planting, 1951 

Clone numbers parentage1 

NE-2, -5, -279, -282 P. nigra L. x P. laurifolia Ledeb. 

NE-9, -10 " x P. trichocarpa Torr. & Gray 

NE-12, -301 " " cv. Betulifolia x P. trichocarpa 

NE-14 I, ,* cv. Charkowienses - 

x P. deltoides Bartr. 

NE-18, -21 ,, 11 11 I* 

11 It I, 

x P. nigra cv. Caudina 

NE-29, -322 * 1, It ,I 

x P. trichocarpa 

NE-31 11 

*, It 0 

x Unidentified cottonwood 

NE-305 x P. nigra cv. Plantierensis 

NE-33 P. deltoides cv. Angulata x P. x berolinensis Dipp. 

NE-34, -259 1) -11 I, 

It 11 I, 11 

x P. nigra cv. Incrassata 

NE-251, -256, -258 11 1, I, l, 

x P. trichocarpa 

NE-261 ,t 1, ,, '** x P. nigra cv. Plantierensis 

NE-264 x P. nigra cv. Volga 

NE-41, -42 P. maximowiczii Henry x P. trichocarpa NE-43, -44, -46, -47, -48, -49, -50 " " vt 11 

x P. x berolinensis 

NE-51, -52 11 7, 

x fi. nigra cv. Plantierensis 

NE-53 x P. nigra cv. Claudina 

WE-200, -r05, -206, -209 P. deltoides x P. trichocarpa 

-212, -213, -219 

NE-223, -224, -227 I* 71 

1, ,1 

x P. nigra cv. Caudina 

NE-229 I, *1 

x P. x berolinensis 

NE-235 11 I, 

x P. x canadensis Moench cv. Incrassata 

NE-239 1, 11 

x P. nigra cv. Volga 

NE-241 r P. nigra cv. Plantierensis 

NE- 333 P. simonii Carr. x P. x berolinensis 

'~~11 names are in accordance with the International Code of Nomenclature for Cultivated 

Plants. 

Clone numbers and the parentage of the hybrids used 

in this study are shown in table 1. The hybrids tested were 

derived from parents in two sections of the genus Populus: 

Aigeiros and Tacamahaca. 

Measurements used in the appraisals that follow were 

made at Horseshoe Run in 1959, and at Parsons in 1957, just 

before the planting at the latter place was removed to make 

room for nursery expansion. Observations were made at both 

sites in 1957 on incidence of leaf rust, insect attack, and 

cankers . 

Heights of the four tallest trees on each plot were 

measured. Then the two 4-tree 'sets representing the two 

replicates of each clone at each site were combined and 

average heights were calculated. The comparisons below are 

based on these 8-tree averages. An example of the variation 

in growth among clones is shown in figure 1. 

Table 2 shows height growth of the 10 best clones at 

the time of the latest measurements at each site, i.e., 9- 

.' year growth at Horseshoe Run and 7-year growth at the nursery. Three clones--NE-46 and NE-50 at Horseshoe Run and 

NE-41 at the nursery--had averaged more than 4.5 feet per 

year. Although rankings among the 10 best clones varied between sites, the lists were in reasonably close agreement: 

7 clones are common to both lists. But 3 clones on each 
list are not common to both, so the two lists each total 13 

clones. 

Table 2 also gives the 7-year growth measurements at 

Horseshoe Run for the 13 clones. These data were included 

for comparison with the 7-year growth at the nursery, and to 

show that growth rates at Horseshoe Run during the last 2 

years were considerably higher than the 7-year averages. Had 

the nursery plantation been continued, similar increases in 

growth rate probably would have occurred there too. 

It is noteworthy that all 13 of these faster growing 

clones listed in table 2 have at least one parent in the 

section Tacamahaca. 

The clones that failed or grew very poorly (table 3) 

usually did so on both sites. It would seem that all these 

clones--certainly those failing at both sites--should not be 

considered for planting on similar soils in this area. 

In general, the clones on the moderately well-drained 

soil at the Parsons Nursery showed a higher incidence of 

canker than those on the well-drained soil at Horseshoe Run. 

However, there was no apparent pattern in the incidence of 

leaf rust and insect attack. 

Some beaver damage occurred at Horseshoe Run in 1952- 

53. This damage is difficult to assess. Where the beaver 

did not cut all the trees on a plot, growth of the remaining 

Figure 1.--After 9 years, 

clone NE-43 (left) had grown 

to an average height of 38 

feet. %is contrasts sharply with the poorer clone NE241 (right), which averaged 

only about half that height. 
ones may have been stimulated by the temporary reduction in 

competition caused by the partial cutting. Some of the 

clones that were most seriously damaged by beaver in 1953 

were among the best in appearance in 1959. In several instances a plot was cleared by the beaver, but the stumps of 

the better adapted clones put out such vigorous shoots that 

very little height growth was lost. 

Table 2.--Height growth of the 10 fastest growing clones at each site, plus 3 clones Table 3.--Clones that failed completely 

at each site that were among the 10 best at the other sitel or grew at a rate of less than 

1.5 feet per year 

'selections of 10 best clones were based on 7-year growth at the Nursery and 

on 9-year growth at Horseshoe Run. 7-year data from Horseshoe Run also are shown. 

Clone 

nlrmber 

'Figures in parentheses are for clones that were not among the 10 best at the 

designated site but were among the 10 best at the other site. 

- Feet - Feet/year - Feet Feet/year - Feet Feet/year 

NE-41 33.2 4.7 21.9 3.1 34.4 3.8 

42 25.6 3.7 (20.5) (2.9) (32.0) (3.5) 

43 (18.9)' (2.7) 23.1 3.3 38.0 4.2 

46 24.2 3.5 24.2 3.5 41.8 4.6 

47 19.2 2.7 21.0 3.0 33.6 3.7 

48 20.2 2.9 (16.9) (2.4) (26.4) (2.9) 

49 23.2 3.3 24.0 3.4 34.0 3.8 

50 22.8 3.2 26.6 3.8 43.8 4.9 

51 24.5 3.5 20.9 3.0 33.8 3.8 

52 23.8 3.4 19.6 2.8 34.0 3.8 

53 19.9 2.8 (21.1) (3.0) (32.0) (3.5) 

206 (16.0) (2.3) 21.2 3.0 32.2 3.6 

256 (14.5) (2.1) 21.2 3.0 32.1 3.6 

Horseshoe Run 

Of the 50 clones used in the test, seven appear to 

have done well enough to be recommended for planting under 

similar climatic conditions on soils of low pH in West Virginia. They are NE-41, 46, 47, 49, 50, 51, and 52. These 

clones all grew at an average rate of 3.6 feet per year or 

better for 9 years on the well-drained Horseshoe Run site; 

all are hybrids of P. maximowiczii. 

Parsons Nursery 

7-year growth 

The largest single tree in the planting was found at 

Horseshoe Run; it was of clone NE-50, whose parents were a 

- Clone - Clone 

number number 

NE- 9 NE- -- 10 10 -- 12 

14 -- 18 18 

31 31 

33 33 

34 34 

205 205 

224 -- 227 227 

229 229 -- 235 

239 239 

261 -- 264 264 

282 2 82 

301 301 

305 305 -- 333 

9-year growth 

Horseshoe Run 

P. maximowiczii and the cultivar P. x- berolinensis. Height 

and diameter of this tree at the end of the ninth growing 

Parsons Nursery 

Average 

total 

growth 

season were 50 feet and 6.1 inches, respectively. 

Average 

total 

growth 

Horseshoe Run 

Mean 

annual 

growth 

--ARTHUR R. ESCHNER 

Research Forester 

Northeastern Forest Experiment Station 

Forest Service, U.S. Dept. Agriculture 

Elkins, W. Va. 

Mean 

annual 

growth 

Average 

total 

growth 

Mean 

annual 

growth