Growth, Yield, and

Disease Resistance of

7- to 12-Year-Old

Poplar Clones in the

North Central United

States

D.A. Netzer, D.N. Tolsted, M.E. Ostry, J.G. Isebrands, 

D.E. Riemenschneider, and K.T. Ward

Forest

Service

North Central

Research Station

General Technical

Report

GTR-NC-229

United States

Department of

Agriculture
Introduction · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · ·1

Materials and Methods · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · ·2

Results · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · ·7

Discussion · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · ·15

Literature · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · ·17

Acknowledgements · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · ·18

Conversion factors for commonly 

used English and metric units · · · · · · · · · · · · · · · · · · · · · · · · · · · · ·18

Appendix 1 · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · ·21

Appendix 2 · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · ·24

Appendix 3 · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · ·27

Appendix 4 · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · ·28

Table of Contents
Growth, Yield, and Disease Resistance of 7- to 12-Year-Old

Poplar Clones in the North Central United States

D.A. Netzer, D.N. Tolsted, M.E. Ostry, J.G. Isebrands, 

D.E. Riemenschneider, and K.T. Ward

Poplar plantations were established across a four-state area in the North Central United States from

1987 to 1992 to determine growth potential and acceptability of clones selected from the available

cultivars for large-scale plantations. Mid-rotation (5 years old) production of the 1987-88 plantings

and clonal ranking based on growth and disease resistance for all plantations were reported

previously. The 1987-88 plantings were remeasured in 1998 at rotation age. Mean annual

increment across all plantings peaked by year 10 with an average production of 7 metric tons per

hectare per year (MTH). The two best sites, Granite Falls, MN and Mondovi, WI averaged 9.2

MTH. Measurements of 7- to 12-year-old clonal trials indicated seven clones that should be tested

further: DN164, DN177, DN154, NM2, NE264, DN170, and DN21.

Abstract

About the Authors:

D.A. Netzer is a Forester

with the Genetic and

Silviculural Systems unit, North

Central Research Station,

Rhinelander, Wisconsin. 

D.N. Tolsted , formerly a

Forestry Technician with the

Silviculture in the Northern

Lake States unit, North Central

Research Station, Rhinelander,

Wisconsin (retired). 

M.E. Ostr y, Research Plant

Pathologist with the Forest

Disease unit, North Central

Research Station, St. Paul,

Minnesota.

J.G. Isebrands, formerly

a Research Plant Physiologist

with the Ecophysiological

Processes unit, North Central

Research Station, Rhinelander,

Wisconsin (retired). 

D.E. Riemenschneider,

a Research Plant Geneticist with

the Genetic and Silviculural

Systems unit, North Central

Research Station, Rhinelander,

Wisconsin.

K.T. Ward is a Forestry

Technician with the Forest

Disease unit, North Central

Research Station, St. Paul,

Minnesota.
A network of poplar plantations was established in

Wisconsin, Minnesota, and North and South Dakota

from 1987 to 1992 to determine growth potential

and acceptability of clones from available cultivars

for large-scale plantings in the North Central Region

(figure 1). Mid-rotation (5 years old) production of

the 1987-88 plantings and clonal ranking based on

growth and disease resistance for all plantations were

reported in Hansen et al. (1994). In the study

reported here, we measured replicated yield blocks of

common clones (older widely planted varieties

including DN34, DN17, DN182) through age 11

years in plantations established in 1987-88 to

develop equations to predict yield. We also measured

growth of up to 95 clones per site of smaller (16

tree) non-replicated plots at 20 plantings in the

region that ranged from 7 to 12 years old, and we

compared their ranking with that in the previously

published report. 

Many hybrid poplar clones planted in the North

Central U.S. have been extensively damaged by

diseases, primarily Septoria canker caused by Septoria

musiva, Melampsora leaf rust caused by Melampsora

spp., and Marssonina leaf spot caused by Marssonina

brunnea (Tuskan 1998). Selection of new and existing

clones with high levels of resistance to the pathogens

is the best disease control strategy. However, selection

of resistant clones may decrease potential biomass

yields because high yielding clones in the section

Tacamahaca are often more susceptible than clones in

the Aigeiros section (Ostry and Berguson 1993).

Ninety-five different poplar clones in 16 research

plantations at 12 locations were assessed annually for

resistance to foliar and stem diseases. Twelve clones

were common to all 16 plantations.

Introduction

1

Figure 1.—Locations of poplar plantations established during 1986-1992 in the North Central United States.
2

The plant materials we tested were predominantly

hybrid poplars from breeding programs in the

Northeastern United States (NE clones) and clones

originally bred in Europe and further tested in

Ontario, Canada (DN clones) (Dickmann and Stuart

1983). In this study, we included four clones that

have been planted extensively in windbreaks in the

North Central United States for a number of years:

DN34 (Eugenei or Imperial Carolina), DN182

(Raverdeau), DN17 (Robusta), and Siouxland. New

promising clones were also included from several tree

breeders in the North Central Region. The parentages

of all the poplar material evaluated in this study are

listed in table 1.

The plantations were established on former

agricultural land that had been in row crops, small

grain, or hay the year before the trees were planted

(appendix 1). Almost all of the trees were grown

from dormant unrooted 25-cm-long hardwood

cuttings. The exceptions were P. deltoides and hybrid

poplar clone NC5339, which were difficult to root

and were planted as 1-year-old rooted cuttings.

Hybrid aspen was planted as 1- or 2-year-old top

pruned seedlings.

Site preparation included glyphosate herbicide

application in the fall prior to planting to kill

perennial grasses and weeds. This was followed by

deep fall plowing and disking. The sites were disked

again in the spring just prior to tree planting. Trees

were planted at 2.4 x 2.4 m with weeds controlled

through a combination of cultivation and herbicides

for 3 years (Hansen et al. 1993). All sites were

sprayed with the pre-emergent herbicide linuron

immediately after dormant, soaked poplar cuttings

were hand planted. Broadleaf weeds and grasses

reinvaded most sites by mid-growing season. Shallow

cultivation and hand weeding around each tree were

moderately successful in controlling these weeds. In

subsequent years tillage was continued as needed on

these sites. Overall weed control varied substantially

but was less than perfect on most sites. Competing

weeds reduced growth, especially in years 1 to 3 on

most sites (Buhler et al. 1998, Netzer and Hansen

1994).

In 1987-88, 0.405-ha blocks of selected clones were

planted at 12 sites to provide for replicated 25-tree

plots for biomass yield estimates. The same trees

were measured throughout the study. Tree survival

and diameter at breast height (DBH) were collected

each fall on the better clones at all sites. Selected

non-measurement trees were periodically harvested,

weighed green, sub-sampled, and ovendried to

determine total tree dry weight (appendix 2). 

DBH and biomass dry weights of selected harvested

trees were used to develop equations to predict

biomass production in metric tons per hectare per

year (MTH) for these 1987-88 large block plantations

through culmination of mean annual increment.

Using these ovendry tree weight data, we developed

biomass regression equations of the form “Tree

weight = a + b * DBH + c * DBH2” to predict

biomass yield in the plantations. We also developed

equations for each site with sufficient trees (n>20),

which included Ashland, Mondovi, Granite Falls, and

Materials and Methods
Table 1.—Poplar clones tested 1987-1992. Some clones not planted each year

Blocks Blocks with Canker2

Clone Parentage Section1 planted live trees (%) mean

NC-5260 P. tristis x P. balsamifera ‘Tristis’ Tx T 16 88 1

NC-5339 P. alba x P. grandidentata ‘Crandon’ Px P 8 38 0

NC-5377 P. deltoides x P. nigra ‘Wisconsin 5’ Ax A 7 57 1

NE-6 P. nigra x P. laurifolia Ax A 15 20 2.3

NE-10 P. nigra x P. trichocarpa Ax T 15 27 3.4

NE-16 P. nigra var. charkowiensis x P. deltoides Ax A 15 40 2.7

NE-17 P. nigra var. charkowiensis x P. nigra var. caudina Ax A 15 67 3.2

NE-19 P. nigra var. charkowiensis x P. nigra var. caudina Ax A 15 93 2.8

NE-20 P. nigra var. charkowiensis x P. nigra var. caudina Ax A 16 94 2.8

NE-21 P. nigra var. charkowiensis x P. nigra var. caudina Ax A 15 80 2.7

NE-22 P. nigra var. charkowiensis x P. nigra var. incrassata Ax A 15 13 3

NE-27 P. nigra var. charkowiensis x (P. laurifolia x P. nigra) Ax TxA 15 27 3.5

NE-28 P. nigra var. charkowiensis x P. trichocarpa Ax T 16 44 2.4

NE-33 P. deltoides var. angulata x P. laurifolia x P. nigra Ax TxA 15 60 1.5

NE-35 P. deltoides var. angulata x P. nigra var. plantierensis Ax A 15 80 1.6

NE-37 P. deltoides var. sargentii x P. laurifolia x P. nigra Ax TxA 15 27 3.2

NE-41 P. maximowiczii x P. trichocarpa ‘Androscoggin’ Tx T 15 47 2.5

NE-42 P. maximowiczii x P. trichocarpa Tx T 15 27 3.1

NE-44 P. maximowiczii x P. laurifolia x P. nigra Tx TxA 15 27 2.6

NE-47 P. maximowiczii x P. laurifolia x P. nigra ‘Oxford’ Tx TxA 15 20 3.6

NE-48 P. maximowiczii x P. laurifolia x P. nigra Tx TxA 15 33 2.7

NE-49 P. maximowiczii x P. laurifolia x P. nigra Tx TxA 15 53 0.8

NE-50 P. maximowiczii x P. laurifolia x P. nigra Tx TxA 1 100 3

NE-51 P. maximowiczii x P. nigra var. plantierensis Tx A 15 53 3.1

NE-52 P. maximowiczii x P. plantierensis Tx A 1 100 3

NE-54 P. balsamifera var. candicans x (P. laurifolia x P. nigra) Tx TxA 15 33 3.3

NE-56 (P. laurifolia x P. nigra) x P. nigra var. caudina TxA A 15 33 2.8

NE-202 P. deltoides x P. trichocarpa Ax T 15 47 2.8

NE-222 P. deltoides x P. nigra var. caudina Ax A 16 100 1

NE-224 P. deltoides x P. nigra var. caudina Ax A 8 88 3

NE-225 P. deltoides x P. nigra var. caudina Ax A 1 100 3

NE-237 P. deltoides x P. nigra cv. Volga Ax A 1 100 0

NE-242 P. deltoides x P. nigra var. plantierensis Ax A 16 63 2.5

NE-252 P. deltoides var. angulata x P. trichocarpa Ax T 15 60 2.3

NE-256 P. deltoides var. angulata x P. trichocarpa Ax T 4 25 3

NE-257 P. deltoides var. angulata x P. trichocarpa Ax T 7 71 1.7

NE-258 (5534) P. deltoides var. angulata x P. trichocarpa Ax T 10 60 2.9

NE-259 P. deltoides var. angulata x P. nigra cv. Incrassata Ax A 15 33 2.9

NE-264 P. deltoides var. angulata x P. nigra cv. Volga Ax A 13 69 0.4

NE-265 P. deltoides var. angulata x P. nigra cv. Volga Ax A 14 57 1.9

NE-283 P. nigra x P. laurifolia Ax T 15 27 3

NE-285 P. nigra x P. trichocarpa Ax T 1 100 3

NE-293 P. nigra var. betulifolia x P. nigra cv. Volga Ax A 5 20 3.3

NE-295 P. nigra var. betulifolia x P. nigra cv. Volga Ax A 15 53 1.5

NE-299 (5331) P. nigra var. betulifolia x P. trichocarpa Ax T 15 47 2.6

NE-300 P. nigra var. betulifolia x P. trichocarpa Ax T 8 63 1.7

NE-308 P. nigra var. charkowiensis x P. nigra cv. Incrassata Ax A 15 87 2.8

NE-351 P. deltoides x P. nigra var. caudina Ax A 7 71 2.8

NE-366 P. deltoides x P. nigra var. caudina Ax A 14 14 3.6

NE-386 (5263) P. balsamifera var. candicans x (P. laurifolia x P. nigra) Tx TxA 8 38 3.3

NE-387 (5262) P. balsamifera var. candicans x (P. laurifolia x P. nigra) Tx TxA 16 44 2.3

NE-389 P. deltoides x P. nigra var. caudina Ax A 3 100 1

DN-1 P. deltoides x P. nigra ‘Allenstein’ Ax A 8 88 1.4

DN-2 P. deltoides x P. nigra ‘Baden’ Ax A 16 94 1.6

DN-5 P. deltoides x P. nigra ‘Gelrica’ Ax A 8 100 0.5

DN-9 P. deltoides x P. nigra ‘Lons’ Ax A 14 93 1.6

DN-16 P. deltoides x P. nigra ‘Regenere Batard d’Hauterive’ Ax A 15 87 1.3

DN-17 P. deltoides x P. nigra ‘Robusta’ Ax A 16 100 1.1

DN-18 P. deltoides x P. nigra ‘Tardif de Champagne’ Ax A 15 93 1.7

DN-21 P. deltoides x P. nigra ‘Jacometti’ Ax A 15 73 1.6

DN-22 P. deltoides x P. nigra ‘I-262’ Ax A 15 73 1.2

DN-28 P. deltoides x P. nigra ‘Ostia’ Ax A 8 63 2.3

DN-34 P. deltoides x P. nigra (Eugenei) Ax A 16 88 0.3

DN-38 P. deltoides x P. nigra Ax A 8 88 2.1

DN-55 P. deltoides x P. nigra Ax A 15 87 1.8

3
4

DN-70 P. deltoides x P. nigra Ax A 8 100 0.4

DN-74 P. deltoides x P. nigra Ax A 8 100 0.3

DN-93 P. deltoides x P. nigra Ax A 5 0 *

DN-106 P. deltoides x P. nigra Ax A 8 88 2.9

DN-114 P. deltoides x P. nigra Ax A 8 75 1.9

DN-128 P. deltoides x P. nigra Ax A 8 100 3

DN-131 P. deltoides x P. nigra Ax A 15 100 1.4

DN-132 P. deltoides x P. nigra Ax A NR3 NR NR

DN-154 P. deltoides x P. nigra Ax A NR NR NR

DN-160 P. deltoides x P. nigra Ax A 8 100 2.5

DN-164 P. deltoides x P. nigra Ax A NR NR NR

DN-170 P. deltoides x P. nigra Ax A 7 100 0.7

DN-173 P. deltoides x P. nigra Ax A 7 86 2

DN-174 P. deltoides x P. nigra Ax A 8 100 1.9

DN-177 P. deltoides x P. nigra Ax A 8 100 1.4

DN-179 P. deltoides x P. nigra Ax A 8 100 1.3

DN-181 P. deltoides x P. nigra Ax A 8 88 1.6

DN-182 P. deltoides x P. nigra (Raverdeau) Ax A 16 81 1.4

I-45/51 P. deltoides x P. nigra Ax A 15 100 0.6

I-476 (4878) P. deltoides x P. nigra Ax A 8 88 0.4

SIOUXLAND P. deltoides x P. nigra Ax A 16 94 1.5

14271 P. deltoides x P. nigra Ax A NR NR NR

IS-31 P. deltoides x P. nigra Ax A NR NR NR

107.14 P. deltoides x P. nigra Ax A NR NR NR

117.53 P. deltoides x P. nigra Ax A NR NR NR

D-101 P. deltoides A NR NR NR

D-102 P. deltoides A NR NR NR

D-103 P. deltoides A NR NR NR

D-104 P. deltoides A NR NR NR

D-105 P. deltoides A NR NR NR

D-108 P. deltoides A NR NR NR

D-109 P. deltoides A NR NR NR

D-110 P. deltoides A NR NR NR

D-111 P. deltoides A NR NR NR

D-112 P. deltoides A NR NR NR

D-113 P. deltoides A NR NR NR

D-114 P. deltoides A NR NR NR

D-118 P. deltoides A NR NR NR

D-122 P. deltoides A NR NR NR

D-124 P. deltoides A NR NR NR

D-125 P. deltoides A NR NR NR

D-115 P. deltoides A NR NR NR

D-117 P. deltoides A NR NR NR

D-119 P. deltoides A NR NR NR

D-121 P. deltoides A NR NR NR

45-1 P. deltoides A 15 100 0

178-4 P. deltoides A NR NR NR

193-5 P. deltoides A NR NR NR

FARGO P. deltoides A NR NR NR

42.7 P. deltoides A NR NR NR

9252.46 P. deltoides A NR NR NR

7300501 P. deltoides A NR NR NR

8000113 P. deltoides A NR NR NR

Jackii4 P. balsamifera x P. deltoides Tx A 16 100 3

NW P. deltoides x P. nigra cv. Volga ‘Northwest’ Ax A 8 75 0.8

DTAC-7 P. deltoides x P. trichocarpa Ax T 6 67 2.5

DTAC-16 P. deltoides x P. trichocarpa Ax T 7 57 2.6

DTAC-26 P. deltoides x P. trichocarpa Ax T 7 57 0.5

HY-5 P. trichocarpa x P. deltoides Tx A 7 0 *

HY-11 P. trichocarpa x P. deltoides Tx A 7 0 *

Table 1.—Continued

Blocks Blocks with Canker2

Clone Parentage Section1 planted live trees (%) mean
5

Milaca. For the remaining sites, we used a

generalized regression equation developed

from all the tree dry weight data from all

sites (n=152) to calculate biomass

production (table 2, appendix 3). 

Each location may have had more than one

planting in different years so “site” refers to a

particular plantation in any one year (table

3). Single 16-tree plots of promising clones

were located in all plantings from 1987

through 1992. The number of clones varied

by year and site and included as many as 76

clones in some instances. These single clone

plots are not replicated on any site for any

one year and were not always planted in

consecutive years: tree DBH, tree survival,

stem canker incidence, and tree form

(1 = stems deformed from sunscald damage

and major stem defects; 2 = crooked stems,

heavy branching, minor defects; 3 = slight

stem sweep, medium branching, no defects;

4 = straight clean stems with few branches)

were recorded and were used to develop

index scores to rank clones in the clonal trial

plots (appendix 4). These rankings were

compared to the mid-rotation rankings

previously reported by Hansen et al. 1994.

Clones with extremely poor growth and

survival were not measured. All clones tested

are listed in table 1.

Clones were assessed annually from 1991

through 1998 for incidence and severity of

foliar and stem diseases, winter injury, and

survival at Cloquet, Fairmont, Granite Falls,

Milaca in MN; Ashland, Rhinelander, and

Mondovi in WI; Sioux Falls, SD; and Fargo,

ND. Clones were replicated across sites and

over time at some sites. A total of 95 clones

(46 to 76 per plantation) were assessed

using the following rating classes for rating

foliage diseases: 0 = none; 1 = slight; 2 =

moderate, infection throughout crown; 3 =

premature defoliation. The following classes

were used for rating stem disease: 0 = none;

1 = branch canker(s) only; 2 = stem

canker(s); 3 = stem dieback and breakage

associated with canker; 4 = death associated

with canker.

NM-2 P. nigra x P. maximowiczii Ax T 8 100 2

NM-6 P. nigra x P. maximowiczii Ax T 8 100 0.3

TRIP P. tremuloides x P. tremula Px P 1 100 0

DIPL P. tremuloides x P. tremula Px P 1 100 0

19-89 P. tremuloides x P. tremula Px P NR NR NR

21-89 P. tremuloides x P. tremula Px P NR NR NR

T50-197 P. trichocarpa x P. deltoides NR NR NR

14044 P. x petrowskyana NR NR NR

14165 P. x ‘Melville’ NR NR NR

14174 P. balsamifera x P. simonii (38P38) NR NR NR

14271 P. deltoides x P. nigra ‘Italica’ #78102 NR NR NR

14390 P. xp., PX71-W131 OP progeny of ‘Walker’ NR NR NR

13277 P. trichocarpa NR NR NR

13279 P. trichocarpa NR NR NR

13280 P. trichocarpa NR NR NR

13281 P. trichocarpa NR NR NR 

2 Canker Rating:

1 = branch canker(s) only.

2 = stem canker(s).

3 = dieback and breakage associated with canker.

4 = death associated with canker

* = death not associated with canker

1 A = Aigeiros

P = Populus (formerly Leuce)

T = Tacamahaca

Table 1.—Continued

Blocks Blocks with Canker2

Clone Parentage Section1 planted live trees (%) Mean

3 NR = not rated.
6

Table 2.—Regression equation coefficients for North Central U.S. poplar plantations and clones

(Tree weight = a + bDBH + cDBH2)

Equation a b c r2 n

General equation 6.16 -2.23 0.353 98.3 152

By site

Ashland, WI 1.86 -0.54 0.245 98.6 35

Mondovi, WI 8.75 -2.97 0.405 99.2 32

Granite Falls, MN 3.05 -1.49 0.327 99.4 28

Milaca, MN 10.20 -2.78 0.357 98.0 44

By clone

DN34 4.73 -1.99 0.349 99.0 41

DN17 4.62 -1.78 0.332 97.7 40

DN182 8.51 -2.86 0.375 98.5 32

Table 3.—Populus clonal trial plantings established in the North Central United States from 1987 through

1992. Each planting originally had 16 trees per clone in unreplicated blocks.

Location Year planted Age measured (years) # Clones measured

Arlington, WI 1991 8 19

Belgrade, MN 1990 9 13

Blackduck, MN 1991 8 12

Cloquet, MN 1988 12 16

Fargo, ND 1987 12 3

Grand Rapids, MN 1989 10 12

Grand Rapids, MN 1992 7 12

Granite Falls, MN 1987 11 11

Hancock, WI 1991 8 17

LaCrosse, WI 1992 7 19

Lancaster, WI 1991 8 28

Milaca, MN 1987 12 15

Milaca, MN 1989 10 11

Mondovi, WI 1987 12 14

Mondovi, WI 1988 11 11

Mondovi, WI 1990 9 15

Sioux Falls, SD 1987 12 10

Sioux Falls, SD 1988 11 11

Sioux Falls, SD 1990 9 2

Sioux Falls, SD 1991 8 2
The 1998 index scores for all clones at all sites along

with average DBH by clone by site and score

adjusted for survival are listed in appendix 4. Three

clones—NE222, I45-51, and DN34—are listed in the

top 12 in all 6 years (table 4). Additionally, DN5,

DN70, DN2, NM6, and DN182 are ranked in the top

12 in 4 of the 6 years. Clones DN177, DN17, and

DN164 are listed in 3 of the 6 years. Several clones,

NM2, NE264, 45-1, DN154, DN131, DN170, DN74,

and DN21 are listed in 2 of the 6 years. If we

compare the top 25 poplars ranked by Hansen et al.

in 1994 with the top 25 in 1998, we see a dramatic

change of ranking in the position of the top clones

although 18 clones were in the top 25 in both years

(table 5).

RESULTS

7

Table 4.—Top 12 clones ranked in descending order by growth, form, and stem canker resistance by year for

hybrid poplar trials planted 1987-1992. Only trees grown from unrooted hardwood cuttings are ranked. Not

all clones were planted in all years.

Rank 12 years old 11 years old 10 years old 9 years old 8 years old 7 years old

1 DN177 NM6 DN5 DN1641 DN164 DN5

2 NE222 DN70 NM6 DN1321 NE222 NM6

3 I45-51 NE252 DN2 DN170 DN177 DN164

4 45-1 NE222 DN70 I45-51 NM2 DN17

5 DN5 DN21 NM2 DN34 DN154 DN182

6 NE264 I45-51 DN182 NE222 NM6 DN70

7 DN170 DN131 DN131 DN2 T50-197 DN34

8 I476 DN34 DN34 DN17 DN34 I45-51

9 DN34 45-1 DN17 DN182 DN70 NE222

10 DN2 DN181 I45-51 DN1321 DN2 DN55

11 DN174 NE264 NE222 DN21 DN5 DN154

12 DN74 DN182 DN74 DN70 I45-51 DN177

1 The first year these clones were planted.

Table 5.—The top 25 clones ranked by growth and disease resistance indices in 1998 compared to 

ranking in 1994 

Clone98 Rank98 Rank94 #Sites98

DN164 1 NR1 8

NM6 2 2 13

DN170 3 11 6

DN5 4 1 14

DN177 5 10 12

NE222 6 8 17

DN70 7 3 12

DN154 8 NR 8

I45-51 9 6 17

45-1 10 20 9

I476 11 12 4

DN34 12 5 17

DN2 13 4 17

NM2 14 17 14

DN182 15 26 17

DN17 16 7 17

NE264 17 14 7

NE252 18 NR 2

DN74 19 16 12

T50-197 20 NR 6

DN132 21 NR 8

DN21 22 NR 16

DN131 23 22 17

DN181 24 29 12

DN55 25 25 16

1 Not ranked in the top 25
8

Table 6.—Growth index scores of hybrid poplar clones planted from 1987 through 1992 in plantations located in Wisconsin, Minnesota, and 

South Dakota 

Index scores = DBH (mm) x survival x (disease + form)

Site* GRF MIL SXF MON CLO MON SXF GRD MIL BEL MON ARL LAN BLD HAN LAX GRD

87 87 87 87 88 88 88 89 89 90 90 91 91 91 91 92 92

Age (yrs) 12 12 12 12 11 11 11 10 10 9 9 8 8 8 8 7 7

Clone GRF MIL SXF MON CLO MON SXF GRD MIL BEL MON ARL LAN BLD HAN LAX GRD

DN2 35 90 0 84 0 65 0 104 72 36 95 14 84 65 49 31 24

DN5 159 99 0 58 NP NP NP 138 102 56 20 31 76 39 56 47 122

DN17 24 59 50 46 0 59 0 56 37 52 57 21 69 46 20 79 67

DN21 0 0 0 0 114 65 0 0 0 0 94 0 92 0 0 NP 0

DN34 28 70 70 53 0 42 75 58 36 72 85 23 104 50 37 62 50

DN55 0 0 0 0 0 0 0 0 0 0 0 0 0 NP 0 0 75

DN70 NP NP NP NP 77 106 83 77 73 56 24 71 87 16 37 NP 59

DN74 0 121 26 26 NP NP NP 0 49 NP NP 79 62 0 41 0 0

DN131 0 0 0 0 123 0 0 110 00 0 0 110 0 0 00

DN132 NP NP NP NP NP NP NP NP NP 96 0 NP NP NP 50 0 NP

DN154 NP NP NP NP NP NP NP NP NP 88 90 88 92 0 54 74 0

DN164 NP NP NP NP NP NP NP NP NP 107 92 137 69 76 56 70 86

DN170 52 34 95 92 NP NP NP NP NP 62 108 NP NP NP 0 NP NP

DN174 121 0 0 60 NP NP NP 0 0 0 0 0 77 0 0 49 0

DN177 165 152 146 127 NP NP NP NP NP 0 70 139 83 0 55 65 0

DN181 NP NP NP NP 102 0 0 0 0 0 0 0 0 0 0 NP 0

DN182 0 52 0 0 58 36 0 84 43 38 65 36 63 32 48 56 76

NE222 60 89 90 103 42 98 41 0 85 50 88 120 127 30 56 43 63

NE252 0 0 0 0 123 NP 0 NP NP NP NP NP NP NP NP NP NP

NE264 0 137 87 87 0 NP 61 NP NP NP NP NP NP NP NP NP 40

NM2 43 61 0 68 NP NP NP 97 46 0 61 29 121 69 38 55 0

NM6 NP NP NP NP 106 90 96 129 107 20 41 33 116 55 20 41 121

I476 48 126 49 0 NP NP NP NP NP NP NP NP NP NP NP NP NP

I45-51 106 98 52 65 51 94 0 17 72 66 102 57 91 40 16 73 34

T50-197 NP NP NP NP NP NP NP NP NP 0 0 41 70 57 NP NP 0

45-1 0 92 88 142 0 105 0 NP NP NP NP NP NP NP NP 0 0

NP = not planted *GRF=Granite Falls, MN 1987, MIL=Milaca, MN 1987, SXF=Sioux Falls, SD 1987, MON=Mondovi, WI 1987,

0 = Poor survival or severely diseased CLO=Cloquet, MN 1988, MON=Mondovi, WI 1988, SFX=Sioux Falls, SD 1988, GRD=Grand Rapids, MN 

1989, LAN=Lancaster, WI 1991, MIL=Milaca, MN 1989, BEL=Belgrade, MN 1990, MON=Mondovi, WI 1990, 

ARL=Arlington, WI 1991, HAN=Hancock, WI 1991, LAX=LaCrosse, WI 1992, GRD=Grand Rapids, MN 1992,

BLD=Black Duck, MN 1991
9

Index scores for clones with a score greater than 100

by site are listed in bold print in table 6. Clone

DN177 and NM6 had scores greater than 100 on five

sites followed by DN5 on four sites. Other clones

ranked high on two and three sites include DN 131,

DN164, NE222, 45-1, and I45-51. It should be

noted that only clones grown from unrooted cuttings

are ranked here. Sites are compared by DBH and soil

texture in table 7. The most productive soil textures

for agricultural crops based on crop equivalency

ratios generally produce more diameter growth;

however, there are exceptions indicating that

multiple factors including clone and cultural

practices are influencing growth. 

Septoria canker was the most damaging disease at all

locations throughout the study, resulting in stem

breakage of many susceptible clones at nearly all the

sites (tables 1, 8). Canker incidence and severity has

increased over time, beginning after the second or

Table 7.—Soil texture of 17 midwest U.S. Populus plantations ranked by mean annual diameter growth of all

clones planted on each site

Sites and Mean annual 

year planted diameter growth (cm) Soil texture

Arlington, WI 1991 2.39 Silt Loam

Granite Falls, MN 1987 2.16 Loam

Mondovi, WI 1988 2.09 Silt Loam

Lancaster, WI 1991 1.94 Silt Loam

Milaca, MN 1987 1.94 Silt Loam

Mondovi, WI 1987 1.94 Silt Loam

Milaca, MN 1989 1.81 Silt Loam

Grand Rapids, MN 1989 1.81 Sandy Loam

Mondovi, WI 1990 1.80 Silt Loam

Hancock, WI 1991 1.69 Loamy Sand

Sioux Falls, SD 1988 1.66 Silty Clay Loam

Belgrade, MN 1990 1.61 Sandy Loam

Sioux Falls, SD 1987 1.58 Silty Clay Loam

Grand Rapids, MN 1992 1.57 Sandy Loam

LaCrosse, WI 1992 1.45 Silt Loam

Cloquet, MN 1988 1.45 Loam

Blackduck, MN 1991 1.34 Unknown

Table 8.—Mean Septoria canker ratings1 and block survival of a) 95 hybrid poplar clones, b) 12 clones 

common to 16 plantings, and c) 51 clones common to nine locations.

ab c

Canker Survival Canker Survival Canker Survival

Location Year rating (%) rating (%) Location rating (%)

Ashland 1987 2.3 95 1.9 100 Ashland 2.1 100

Ashland 1988 1.7 98 1.2 100 Cloquet 0.3 92

Cloquet 1988 0.3 90 0.4 100 Fairmont 2.4 76

Fairmont 1986 1.3 36 0.7 75 Fargo 2 24

Fairmont 1988 2.4 52 1.7 92 Granite Falls 2.1 59

Fargo 1987 1.7 33 2.8 42 Milaca 2.8 96

Granite Falls 1987 1.6 36 1.4 58 Mondovi 1.8 88

Granite Falls 1988 2.2 39 1.9 67 Rhinelander 2 94

Milaca 1987 2.7 75 2.7 92 Sioux Falls 3 82

Milaca 1989 1.7 100 2.2 100

Mondovi 1987 1.5 71 1.1 92

Mondovi 1988 1.7 67 1.6 92

Rhinelander 1987 1.8 82 1.6 100

Rhinelander 1988 2 77 1.8 100

Sioux Falls 1987 2.8 52 2.5 92

Sioux Falls 1988 2.9 48 2.1 75

1

0 = none, 1 = branch canker(s) only, 2 = stem canker(s), 3 = dieback and

breakage associated with canker, 4 = death associated with canker.

Data collected 1995-1998.
1

0 =none, 1 = branch canker(s)

only, 2 = stem canker(s), 

3 =dieback and breakage

associated with canker, 

4 = death associated with canker.

Data collected 1995-1998.

10

third year after planting. In 1998, the mean canker

rating of the 12 clones common to all plantings was

greater in the 1989 plantings (2.2) than in the 1987

(2.0), 1988 (1.5), or 1986 (0.7) plantings (fig. 2).

Canker incidence and severity varied across

locations. Canker damage on the 12 common clones

was lowest at the Cloquet-88 and Fairmont-86

plantings, and it was greatest at the Fargo-87 and

Milaca-87 plantings (table 8, fig. 3). Clone survival

(blocks with live trees) was greatest at the Milaca-89,

Ashland-87 and -88, and Cloquet-88 plantings (table

8). The poorest survival was at the Fargo-87 and

Granite Falls-87 and -88 plantings. 

There were differences among clones of the various

Populus sections in resistance to Septoria canker.

Populus (=Leuce) section hybrids, P. deltoides clones,

and certain P. deltoides x P. nigra and P. nigra x P.

maximowiczii hybrids were the most canker resistant

(table 1). Clones with little or no Septoria canker and

with above average survival included 45-1, diploid

and triploid aspen, DN74, NE237, NM6, I476,

DN34, and DN70. Hybrids most susceptible to

Septoria canker were those in the section

Tacamahaca, and clones with P. nigra parentage.

Clones most severely damaged by Septoria canker

were NE366, NE386, NE51, DTAC16, NE17,

NE224, NE52, NE50, NE389, NE285, NE225,

Jackii 4, and DN128. Some of the highest yielding

clones were also susceptible to canker (fig. 4). While

some clones were either highly resistant or highly

susceptible across sites, others were highly variable in

canker susceptibility depending on site (table 9).

Figure 2.—Mean Septoria canker ratings1 and block survival of

95 hybrid poplar clones in 16 plantings established 1986-1989.

Figure 3.—Mean Septoria canker ratings1 and block survival of a) ninety-five 8- to 10-year-old hybrid poplar clones, b) 51

clones common to all nine locations, and c) 12 clones common to all 16 plantings.

1

0 =none, 1 = branch canker(s) only, 2 = stem canker(s), 3 = dieback

and breakage associated with canker, 4 = death associated with

canker. Data collected 1995-1998.
1

0 =none, 1 = branch canker(s)

only, 2 = stem canker(s), 

3 =dieback and breakage

associated with canker, 

4 = death associated with canker.

Data collected 1995-98.

11

Leaf diseases were generally not a serious problem in

hybrid poplar plantations although the major foliar

pathogens M. medusae, M. brunnea, and S. musiva

were present at all of the sites. Leaf disease severity

was variable during this study and highly dependent

on climatic conditions. One exception was the yearly

premature defoliation of clone ‘Northwest’ that was

caused by M. medusae. Various other clones were

partially defoliated by leaf rust. Depending on

seasonal weather patterns, several other clones were

partially defoliated by M. brunnea and S. musiva.

Trees at the Cloquet, MN, site had the lowest disease

severity of all sites. Although the incidence of

Septoria canker began to increase 6 years after

planting, for reasons unknown, susceptible clones at

this site continued to have levels of disease

significantly less than at all of the other sites.

Comparisons of edaphic factors among the planting

sites and the canker severity and tree survival

revealed that precipitation and soil acidity may have

had more influence than other soil characteristics

(fig. 5).

Biomass yields of poplar plantations established in

WI, MN, ND, and SD during 1987-88 through years

10 and 11 are reported here as well as estimated

yields of the best performers in the small clonal

trials. Hansen et al. 1994 reported mid-rotation (4-

and 5-year-old) yields of the 1987-88 plantings in

1992. They reported that the mean annual increment

had not peaked (trees were still growing each year at

a greater rate than the year before) in the plantations.

Therefore, we continued measurements until all

plantations began to decline. We selected three

Figure 5.—a) Mean Septoria canker ratings1 and b) block survival, of fifty-one 8- to 10-year-old hybrid poplars common to

nine locations, and soil acidity. 

Figure 4.—Mean Septoria canker ratings1 and biomass

production of five hybrid poplar clones in eight locations.

1

0 =none, 1 = branch canker(s)

only, 2 = stem canker(s), 

3 =dieback and breakage

associated with canker, 

4 = death associated with canker.

Canker data collected on 8- to

10-year-old clones in 1995-1998

and biomass data collected in

1991 on 6-year-old clones. 
12

Table 9.—Variance in mean Septoria canker ratings of 8- to 10-year-old hybrid poplar clones in 16 plantings

Clones highly resistant across sites Blocks Surviving Canker Canker

Clone Parentage planted blocks (%) variance rating1

45-1 P. deltoides 15 100 0 0.0

NC5339 P. alba x P. grandidentata 8 38 0 0.0

DN4 P. deltoides x P. nigra 8 100 0.50 0.3

NM6 P. nigra x P. maximowiczii 8 100 0.50 0.3

DN34 P. deltoides x P. nigra 16 88 0.53 0.3

DN70 P. deltoides x P. nigra 8 100 0.55 0.4

NE264 P. deltoides var. angulata x P. nigra cv. Volga 13 69 1.03 0.4

I476 P. deltoides x P. nigra 8 88 1.29 0.4

Clones highly susceptible across sites

NE224 P. deltoides x P. nigra var. caudina 8 88 0 3.0

DN128 P. deltoides x P. nigra 8 100 0 3.0

JACKII4 P. balsamifera x P. deltoides 16 100 0 3.0

DN106 P. deltoides x P. nigra 8 88 0.14 2.9

NE386 P. balsamifera var. candicans x P. laurifolia x P. nigra 8 38 0.25 3.3

NE366 P. deltoides x P. nigra var. caudina 14 14 0.30 3.6

NE17 P. nigra var. charkowiensis x P. nigra var. caudina 15 67 0.31 3.2

NE51 P. maximowiczii x P. nigra var. plantierensis 15 53 0.32 3.1

NE27 P. nigra var. charkowiensis x P. laurifolia x P. nigra 15 27 0.50 3.5

NE47 P. maximowiczii x P. laurifolia x P. nigra 15 20 0.53 3.6

NE10 P. nigra x P. maximowiczii 15 27 0.53 3.4

NE22 P. nigra var. charkowiensis x P. nigra cv. Incrassata 15 13 1.00 3.0

Clones exhibiting variable canker ratings across sites2

NE44 P. maximowiczii x P. laurifolia x P. nigra 15 27 3.78 2.6

NE300 P. nigra var. betulifolia x P. trichocarpa 8 63 3.47 1.7

NE257 P. deltoides var. angulata x P. trichocarpa 7 71 3.47 1.7

DN114 P. deltoides x P. nigra 8 75 3.14 1.9

NE265 P. deltoides var. angulata x P. nigra cv. Volga 14 57 2.99 1.9

NE295 P. nigra var. betulifolia x P. nigra cv. Volga 15 53 2.94 1.5

NE252 P. deltoides var. angulata x P. trichocarpa 15 60 2.93 2.3

NE6 P. nigra x P. laurifolia 15 20 2.92 2.3

DN28 P. deltoides x P. nigra 8 63 2.90 2.3

DN22 P. deltoides x P. nigra 15 73 2.86 1.2

1

0 = none, 1 = branch canker(s) only, 2 = stem canker(s), 3 = dieback and breakage associated with canker,

and 4 = death associated with canker.

2

Generally, lower canker ratings in Ashland 1988 and Cloquet 1988 plantings,

and higher canker ratings in Fairmont 1988, and in Sioux Falls 1987 and 1988.

Data collected 1995-1998.

Figure 7.—Combined average production of hybrid poplar clones DN17,

DN34, and DN182 planted in 1988 at six locations in the North Central U.S.

Figure 6.—Combined average production of hybrid poplar clones DN17,

DN34, and DN182 planted in 1987 at six locations in the North Central U.S.
replications of plots of 25 trees (including older

widely planted varieties DN34, DN17, DN182)

immediately after planting for each clone on each 

site tested.

Biomass production in the 10- and 11- year-old

plantations in 1997 ranged up to 9.4 MTH (table

10). Peak production for all sites was nearly identical

for the 1987 and 1988 plantings at 7 MTH (figs. 6

and 7). The best three sites (Granite Falls, Milaca,

Mondovi) in the 1987 plantings had an average

production of 8.3 MTH while the two best sites in

1988 (Granite Falls, Mondovi) had an average

production of 9.2 MTH. Production peaked earlier in

the 1988 plantings with all but Cloquet peaking in

year 6 or 7. The 1987 plantings peaked later in the

rotation with Granite Falls and Milaca peaking at

year 10 while the other three sites peaked at year 8

or 9. After MTH peaked, the standing biomass on a

site (fig. 8) continued to climb. This allowed

plantation managers the option of harvesting for a

few years beyond the peak production with a

plantation still increasing in MTH, although at a

reduced rate.

13

Figure 9.—Production of two hybrid poplar clones at 12

years at Granite Falls, MN (GRF); Milaca, MN (MIL); Sioux

Falls, SD (SXF); and Mondovi, WI (MON), and at 8 years

at Arlington, WI (ARL).

Figure 8.—Combined average yield per hectare for hybrid

poplar clones DN17, DN34, and DN182 in six midwest

plantations established in 1987.
14

Table 10.—Biomass production in dry metric tons per hectare per year and (dry tons per acre per year) for hybrid

poplar plantations planted in 1987 and 1988 at several North Central U.S. locations. Based on the mean of 25-

tree replicated blocks of DN34, DN17, and DN182.

Plantation established in 1987

Ashland Fargo Granite Falls Milaca Mondovi Sioux Falls

Year 3 (1989) NM1 NM NM 1.68 1.23 NM

(0.75) (0.55)

Year 4 (1990) NM NM NM 3.47 4.08 NM

(1.55) (1.82)

Year 5 (1991) 2.17 4.15 3.65 4.71 5.67 2.46

(0.97) (1.85) (1.63) (2.10) (2.53) (1.10)

Year 6 (1992) 2.85 3.93 4.26 5.67 7.24 3.88

(1.27) (1.75) (1.90) (2.53) (3.23) (1.73)

Year 7 (1993) 3.36 6.39 7.62 6.73 8.59 4.48

(1.50) (2.85) (3.40) (3.00) (3.83) (2.00)

Year 8 (1994) 3.52 7.17 8.18 7.40 8.23 5.09

(1.57) (3.20) (3.65) (3.30) (3.67) (2.27)

Year 9 (1995) 3.50 7.17 8.52 7.49 8.11 5.13

(1.56) (3.20) (3.80) (3.34) (3.62) (2.29)

Year 10 (1996) NM 7.94 8.65 7.89 7.80 4.77

(3.54) (3.86) (3.52) (3.48) (2.13)

Year 11 (1997) 4.04 NM 8.43 7.71 7.55 NM

(1.80) (3.76) (3.44) (3.37)

Plantations established in 1988

Ashland Cloquet Fairmont Granite Falls Mondovi Sioux Falls

Year 3 (1990) 4.60 NM

(2.05)

Year 4 (1991) 3.74 2.80 4.33 4.33 6.12 2.76

(1.67) (1.25) (1.93) (1.93) (2.73) (1.23)

Year 5 (1992) 4.33 3.92 5.09 5.22 7.85 3.59

(1.93) (1.75) (2.27) (2.33) (3.50) (1.60)

Year 6 (1993) 4.77 4.15 7.02 9.12 8.97 5.09

(2.13) (1.85) (3.13) (4.07) (4.00) (2.27)

Year 7 (1994) 4.77 4.93 7.24 9.48 8.90 5.45

(2.13) (2.20) (3.23) (4.23) (3.97) (2.43)

Year 8 (1995) 4.69 5.38 7.17 9.46 8.83 5.42

(2.09) (2.40) (3.20) (4.22) (3.94) (2.42)

Year 9 (1996) NM 6.05 7.17 9.26 7.71 5.27

(2.70) (3.20) (4.13) (3.44) (2.35)

Year 10 (1997) NM 5.6 NM NM 7.20 NM

(2.50) (3.21)

1

NM = no measurements made to calculate yields.
This study confirms that successful production of

hybrid poplars on 5- to 10-year rotations in the

North Central United States will require disease

resistant clones for establishing plantations. Results

of these clonal trials support previous

recommendations that clones be tested under local

conditions before large areas are planted. Many

clones exhibited good early growth but failed midway in the rotation because of their susceptibility to

disease. Some clones that did not rank as top clones

at mid-rotation were the top producers at the end of

the rotation.

From 1989 to 1992, rooted stock of hard to root

clones was included in the clonal trials. They are

included in the ranking of all clones at all sites in

appendix 3 and include pure P. deltoides and the P.

alba-hybrid NC5399. Many of these rank very high

and may warrant further testing. Comparison

between rooted and unrooted stock is difficult due to

differences in growth and survival in the

establishment year. Evaluation of production costs

may determine whether rooted stock of selected

materials may be planted in certain situations.

Establishment and growth of all poplar clones is

influenced by environmental and cultural stresses.

Competing weeds are the most important stress

factor in decreasing poplar plantation success

(Hansen and Netzer 1985). Plantation growth has

improved where land managers’ efforts in the

establishment year to control weeds continued as late

as August. Hybrid poplar growth in August often

makes up a large portion of the growth for the year

in the Midwest U.S. Poplar growth is reduced

throughout the life of the plantation by competing

weeds until they are controlled chemically,

mechanically, or by shading of the plantation canopy.

Good site preparation is the next critical factor for

success and makes controlling weeds much easier.

For good poplar growth, sites should have deep,

fertile sandy-loam to clay-loam soils with a pH

between 5 and 7.5, and should be well drained, but

not droughty (Hansen et al. 1993). Local testing to

determine clone-site matching is critical. Selection of

good sites can be difficult and not necessarily tied to

one factor. For example, table 7 lists the best and

worst sites that occur on a generally accepted

productive soil, a silt loam. 

Other site factors including climate, drainage, and

location must be considered. Soils with high pH

(>7.8) will likely be difficult to establish poplar

plantations on. Plantations that we established in

1987-88 were planted during a historic (100 year)

drought that may have initially reduced growth. We

also recorded years with record rainfall on several

sites. Despite these weather events of historic

proportions, we were able to successfully establish

poplar plantations. Appropriate cultural methods

used on good sites apparently can overcome severe

weather in plantation establishment.

Previous mid-rotation clonal recommendations

(Hansen et al. 1994) included nine clones (DN34,

DN17, DN182, DN2, DN5, DN70, NM6, NE222,

and I45-51). Our ranking in table 6 lists seven of

these with index scores of 100 or more on at least

one site. Clone DN17 and DN182 did not have an

index score of 100 or greater at any site. In table 4

we find all previously recommended clones in the

top 12 at least 3 of the 6 years measured. It should

be noted, however, that in years 10 and 11 only 12

clones had index scores high enough to be included

in the rankings. New clones not previously

recommended have ranked consistently high and in

DISCUSSION

15
some cases higher than previously recommended

clones. These include DN177, DN154, DN164,

DN21, DN170, NM2, and NE264. 

Biomass production in North Central hybrid poplar

plantations tested was greater than 6.7 MTH. Yields

on better sites average near or slightly above 9 MTH.

Generally, peak production at 2.4 by 2.4 m spacing

will be between years 7 and 10 in the Midwest U.S.

with adequate weed control, limited fertilization, and

non-selected clones. The potential for greater

production through clonal selection can be seen if we

calculate the yield of DN177 and compare the MTH

to the standard clone DN34 on the same site at the

same age (fig. 9). DN177 has a production of 22.6

MTH at Arlington, WI, compared to 7.2 MTH for

DN34 at 8 years. At Granite Falls, MN, the 12-yearold planting would have a yield of 23.5 MTH for

DN177 compared with 5.7 MTH for DN34.

Although these data are calculated from unreplicated

small plots, they do illustrate the potential. Clonal

breeding and selection, mid-rotation fertilization, and

improved weed control all have the potential to

greatly increase the yields reported here. Landowners

must test clones on their particular sites to determine

suitability. Local testing of promising poplar clones

and use of the best cultural practices available will

ensure successful poplar plantations. 

16
Buhler, D.D.; Netzer, D.A.; Riemenschneider, D.E.;

Hartzler, R.G. 1998. Weed management in short

rotation poplar and herbaceous perennial crops

grown for biofuel production. Biomass and

Bioenergy. 14: 385-394.

Dickmann, D.I.; Stuart, K.W. 1983. The culture of

poplars in Eastern North America. East Lansing,

MI: Michigan State University Department of

Forestry. 168 p.

Dickmann, D.I.; Isebrands, J.G.; Eckenwalder, J.E.;

Richardson, J., eds. 2001. Poplar culture in North

America. Ottawa, ON, Canada: NRC Research

Press. 397 p.

Hansen, E.A.; Netzer, D.A. 1985. Weed control using

herbicides in short-rotation intensively cultured

poplar plantations. Res. Pap. NC-260. St. Paul,

MN: U.S. Department of Agriculture, Forest

Service, North Central Forest Experiment Station.

6 p.

Hansen, E.A.; Netzer, D.A.; Tolsted, D.N. 1993.

Guidelines for establishing poplar plantations in

the north-central U.S. Res. Note NC-363. St. Paul,

MN: U.S. Department of Agriculture, Forest

Service, North Central Forest Experiment 

Station. 6 p.

Hansen, E.A.; Ostry, M.E.; Johnson, W.D.; Tolsted,

D.N.; Netzer, D.A.; Berguson, W.E.; Hall, R.B.

1994. Field performance of Populus in shortrotation intensive culture plantations in the northcentral U.S. Res. Pap. NC-320. St. Paul, MN: U.S.

Department of Agriculture, Forest Service, North

Central Forest Experiment Station. 13 p.

Netzer, D.A.; Hansen, E.A. 1994. Establishment and

tending of poplar plantations in north-central U.S.

In: Stokes, B.J.; McDonald, T.P., eds. IEA/BA task

9 activity 1 short rotation intensive culture

forestry; 1994 March 1-3; Mobile, AL. Mobile, AL:

IEA/BA SRIC Mechanization: 79-87.

Ostry, M.E.; Berguson, W.E. 1993. Selecting hybrid

poplars to reduce disease risk may also reduce

biomass yield. Tree Planters’ Notes. 44(3): 128-

131.

Tuskan, G.A. 1998. Short-rotation woody crops:

What we know and what we need to know.

Biomass and Bioenergy. 14: 307-315.

Literature Cited

17
Conversion Factors for Commonly Used 

English and Metric Units

Many individuals, State and Federal agencies and

universities cooperated to make the establishment

and maintenance of these poplar plantations possible

in Minnesota, Wisconsin, and North and South

Dakota. A few are mentioned here. 

Ed Hansen, USDA Forest Service-North Central

Research Station (retired), provided leadership and

extensive personal sacrifice in establishing and

maintaining these studies. Bill Berguson of the

University of Minnesota’s Natural Resources Research

Institute-Duluth and Wendell Johnson of the

University of Minnesota-Crookston provided planting

sites and expertise for several of the plantations in

northern Minnesota. The University of WisconsinMadison provided several sites on its experimental

farms. Adrian Hagen, Wisconsin Department of

Natural Resources, provided a planting site near La

Crosse, WI. Tim O’Brien, University of MinnesotaGrand Rapids Nursery, provided sites and cultural

treatments for several plantations. Individual farmers

and landowners in the four-state area provided

plantation sites, equipment, and cultural expertise for

the remainder of the study areas.

Research for these studies was partially funded by the

U.S. Department of Energy under Interagency

Agreements #DE-A105-89OR21871 and #DE-105-

95OR22434.

The following tree breeders provided plant material

for these studies:

• Carl Mohn, University of Minnesota, Department

of Forest Resources, 1530 N. Cleveland Ave., St.

Paul, MN 55108 (retired)

• Gary Wyckoff, University of Minnesota, North

Central Experiment Station, 1861 East Highway

169, Grand Rapids, MN 55744 (Currently at Mead

Corporation, Escanaba, MI)

• Don Riemenschneider, USDA Forest Service,

North Central Research Station, Forestry Sciences

Laboratory, 5985 Highway K, Rhinelander, WI

54501

• Richard Cunningham, USDA Agricultural Research

Service, P.O. Box 459, Mandan, ND 58554

(retired)

• Bernie McMahon, Iowa State University,

Department of Forestry, 251 Bessey 17 Hall, Ames,

IA 50011 (Currently at University of MinnesotaNRRI, Duluth, MN)

Acknowledgments

18

Multiply by X to convert metric to U.S. Multiply by Y to convert English to metric

X Y

.3937 inch • • • • • • • • • • • • • • • • • • • • •2.5400 centimeter (cm) 

3.2808 foot (ft) • • • • • • • • • • • • • • • • • • • • • •.3048 meter (m) 

1.1023 ton (t) • • • • • • • • • • • • • • • • • • • •.9072 metric ton (mt) 

.4461 ton per acre (t/a) • • • • • • • • • • • • • •2.2417 metric ton per hectare (mth)

2.4710 acre (a) • • • • • • • • • • • • • • • • • • • • •.4047 hectare (h) 
Poor weed control will reduce growth and survival and will

lead to plantation failure.

 Good weed control is essential for

optimum growth and survival in poplar

plantations. Biomass production equations were developed

from periodic tree harvest.

Choose poplar plantation sites that have deep,

fertile sandy-loam to clay-loam soil with a pH

between 5 and 7.5 for best results. Test soil

fertility, and fertilize according to corn

recommendations. Nitrogen is the element most

often deficient.

Selection of disease resistant poplars is critical to

plantation success.
Milaca, MN 1987

Located on private land in east central Minnesota. The

1987 hybrid trial is planted in a rocky, low-lying field

that was formerly in hay and pasture. The water table

is close to the ground surface often flooding with

spring snowmelt and heavy precipitation. Early weed

control was adequate mainly through cultivation and

hand weeding. Septoria canker and sunscald are both

present. The planting is protected from wind by

woodlots on two sides. Good growth of poplars may

be related to the high water table.

Milaca, MN 1989

Located on higher ground just west of the 1987

planting and does not benefit from a high water table.

The soil is somewhat rocky, and was used for hay

production prior to planting poplars. Control of weeds

was adequate. Sunscald is present on some clones

causing severe scarring of the trunks. Cankering is

severe on stems of many clones. The planting is

protected on two sides with native woodlots. 

Granite Falls, MN 1987

Located in south central Minnesota just east of the

Northern States Power plant on company land. The

plantation is in a low-lying area on the Minnesota River

flood plain. It is considered good agricultural soil and

was used mostly for alfalfa production. The planting is

protected on one side with natural woodlot and on

another by high road banks. Several clones were

removed early in the rotation due to relocation of an

adjacent road. Outbreaks of cottonwood leaf beetles

damaged new tree growth throughout the plantation

rotation.

Mondovi, WI 1987

Located in west central Wisconsin on private land at

the northern edge of the driftless (unglaciated) coulee

region. The planting is on a southwest-facing slope

protected by natural woodlots and steep terrain. This

site is considered a productive agricultural site. It was

in corn production until 1986. Heavy weed cover was

removed in 1987 prior to planting. Weed control was

adequate in the first 3 years followed by an invasion of

taller weeds including giant ragweed. First-year tree

growth was poor due to drought conditions but

subsequent growth was considered good.

Mondovi, WI 1988

The 1988 hybrid trial is located adjacent to the 1987

planting on a southeast-facing slope. This planting has

an agricultural history similar to the 1987 planting.

Growth early in the rotation was exceptional. A

dramatic reduction in growth and increases in stem

disease occurred in the second half of the rotation

from unknown causes, possibly from contaminated

runoff from a nearby gravel pit.

Mondovi, WI 1990

This plantation is located near the 1987 and 1988

plantings and has similar history and growth. This

site was first planted in 1989 and failed due to poor

weed control. There is concern that coppicing from

the 1989 planting may be confused with trees in the

1990 planting.

Lancaster, WI 1991

Located at the University of Wisconsin-Lancaster

Experimental Farm in the southwest corner of

Wisconsin’s driftless area. The site is highly productive

agricultural landscape that is farmed for corn in

contour strips alternated with grass strips to prevent

erosion. The plots are located in several of these 20-

foot-wide strips with the last contour next to a natural

woodlot. Growth was reduced in the trees nearest the

woods from shading and continued deer browse. This

Appendix 1— 

Description of Populus plantations established from 1987 to 1992 in

Minnesota, Wisconsin, and North and South Dakota 

21
was one of the more productive sites relative to overall

growth and survival of many clones. A red clay layer

between the topsoil and limestone bedrock transfers

water downslope, creating a good moisture supply for

the tree roots. Grass, mainly foxtail, caused tree

growth reduction in the establishment years.

Hancock, WI 1991

Located at the University of Wisconsin-Hancock

Experimental Farm in central Wisconsin. The hybrid

trial is planted on a light sandy soil that is subject to

drought. The site was in hay before trees were planted.

Potatoes grown under irrigation are the typical crop

for this area. The plantation is in the open and not

protected from wind. Early weed control was adequate

with severe sunscald and stem canker present on

many clones. Poplar plantings on this site would do

best with irrigation and fertilization.

LaCrosse, WI 1992

Located on the Coulee Experimental Forest managed

by the Wisconsin Department of Natural Resources.

The site is on a southwest-facing slope on a ridgetop in

the driftless area of west central Wisconsin. The field

was in continual hay production until it was site

prepped for tree planting. The soil is a somewhat

eroded silt loam over limestone bedrock. The tree plots

are planted in 20-foot-wide contour strips separated by

grass. Early weed control was difficult because the

slope allowed for tillage in only one direction. Intense

deer browse significantly reduced first-year growth. An

electric fence installed at the end of the first season

reduced but did not eliminate damage. The planting is

exposed to south and southwest winds. Growth varies

across the site with the best growth on the upslope

grading to poorer growth on the downslope. Disease

incidence is minimal.

Grand Rapids, MN 1989

Located in north central Minnesota at the University of

Minnesota’s North Central Research Station Nursery.

The planting is on a sandy loam soil that has been in

experimental field plots for many years. Several hybrid

clones are growing well here that are not growing well

at most field sites. Tree pruning has produced severe

stem scarring on lower stems. Weed control was

adequate. Sunscald affects some clones. Disease

incidence appears to be low in this planting.

Grand Rapids, MN 1992

Located near the 1989 plantation. Poplars are smaller

in this site than would be expected for their age.

Continued deep disking may have caused some root

damage to the trees. Sunscald is less than in the 1989

planting, and similar stem scars appear from pruning.

Incidence of stem canker appears slightly higher here

than in the 1989 planting.

Sioux Falls, SD 1987

Located on a private farm 1 hour west of Sioux Falls

in southeast South Dakota. The 1987 plantation is

located on fertile farmland that had been in corn and

soybean production. Weed control was excellent in the

establishment years. Stem cankering has caused stem

breakage of many clones. Additional damage occurred

to treetops and some stems from a severe ice storm in

1996. The plantation is exposed to winds except on

the south side, which is protected by a woodlot.

Sioux Falls, SD 1988

The 1988 plantation is located one-fourth mile west of

the 1987 plantation. Soils are poor with limited

grazing occurring prior to plantation establishment.

The site faces east grading into lowland to the north.

The soils are rocky and eroded resulting in poor tree

growth. There is heavy stem cankering here. Only 5

Appendix 1—Continued

22
out of 65 clones planted were deemed good enough

for measurement.

Sioux Falls, SD 1990

The plantation is located in a failed part of the 1987

plantation. Early weed control was poor resulting in

failure of most of the planted stock except the rooted

deltoides. In 1991 a small area was again replanted

with hybrid poplar clones DN164 and DN154

surviving and showing potential for this site.

Arlington, WI 1991

Located on the University of Wisconsin Experimental

Farm-Arlington in south central Wisconsin. The site

consists of deep silt loam soils and was in alfalfa

production prior to plantation establishment. It is

protected on the south by a windbreak. Tree growth

potential is very high although many trees suffer from

stem canker, sunscald, and wind damage. 

Cloquet, MN 1988

Located on private land in northeast Minnesota. The

1988 plantation is on a nutrient poor silt loam soil

intermixed with gravel and small rock deposits.

Agricultural production is considered marginal on this

site with much of the history in hay production. This

plantation has had the lowest disease incidence

through most of the rotation of any planting site in

our trials. A number of NE clones that are susceptible

to stem cankers perform better here than the same

clones at other sites. This site is exposed to winds

from the north.

Belgrade, MN 1990

Located on private land in central Minnesota east and

south of Westport. The site was formerly in corn and

small grains. The west side of the plantation is a low

poorly drained area that produced very poor tree

growth. Vigor and tree size are better grading to the

higher ground on the east side of the plot. Early weed

control was limited especially on the wet east edge.

Stem canker is present but little tree breakage has been

observed. No sunscald has been observed. Ranking of

the clones on this site can be related to location in the

plot in addition to disease factors. The plantation is

unprotected and subject to prairie winds.

Blackduck, MN 1991

Located on private land in north central Minnesota.

This site is low lying with infertile sandy loam soils.

Trees are smaller than on other sites planted in 1991.

Early weed control was poor contributing to the

reduced tree growth. Trees are damaged in the upper

crown due to a hail storm. Disease and sunscald are

minimal on this site. The planting is protected from

wind by native aspen stands.

Fargo, ND 1987

Located on private land near the intersection of

Interstates 94 and 29 on the southwest edge of Fargo.

The soils are poorly drained clay with an area on the

west side mixed with rubble deposits left from road

construction. The site is productive for small grains

and melons but frequent spring flooding combined

with poor drainage has reduced tree growth. The site

is not protected from prairie winds and is a marginal

planting site at best. Only three clones were measured

at 12 years. Of note is that DN2 had a growth index of

greater than 100 (104). Subsequent attempts to

establish plantings in 1988, 1989, and 1992 failed.

Severe winter damage along with cankering occurs on

the surviving trees.

Appendix 1—Continued

23
24

Site Clone DBH (cm) HGT (m) Dry wgt (Kg) Tree age (yrs)

Ashland DN34 13.8 10.3 40.7 7

Ashland DN34 11.5 9.8 27.62 7

Ashland DN34 10.3 9.3 21.88 7

Ashland DN34 9.5 9.1 15.46 7

Ashland DN34 8.3 7.5 15.34 5

Ashland DN34 3.1 3.6 3.51 3

Ashland DN34 2.7 3.4 2.09 3

Ashland DN34 2.6 3.3 2.19 3

Ashland DN34 1.8 2.6 1.16 3

Ashland DN34 1.2 2.2 0.47 3

Ashland NE308 10.1 9.2 17.66 5

Ashland NE308 5.3 5.1 5.17 3

Ashland NE308 4.2 4.4 4.31 3

Ashland NE308 3.5 3.9 2.84 3

Ashland NE308 2.8 3.3 2.48 3

Ashland NE308 2 2.9 0.97 3

Ashland DN182 8.9 8 19.38 5

Ashland DN182 3.5 4.3 4.79 3

Ashland DN182 3.3 4.2 4.29 3

Ashland DN182 2.2 3.2 2.17 3

Ashland DN182 2 2.7 1.49 3

Ashland DN182 1.6 2.2 0.99 3

Ashland DN17 13.7 11 42.8 7

Ashland DN17 11.7 11.3 29.84 7

Ashland DN17 10.6 10.7 22.37 7

Ashland DN17 9.4 10.1 18.49 7

Ashland DN17 7.8 8.1 14.73 5

Ashland DN17 5 6.3 6.12 5

Ashland DN17 4.2 4.1 3.96 3

Ashland DN17 3.6 4.2 3.72 3

Ashland DN17 3.2 3.9 2.85 3

Ashland DN17 2.5 3.4 2.07 3

Ashland DN17 2.2 3.1 1.67 3

Ashland DN17 1.9 2.8 0.72 3

Ashland Siouxland 7.5 6.7 9.6 5

Granite Falls DN34 22.9 * 132.7 10

Granite Falls DN34 22.2 17.5 128.2 10

Granite Falls DN34 19.3 15.6 93.16 8

Granite Falls DN34 18.5 16.3 83.5 8

Granite Falls DN34 17.5 15.3 72.4 8

Granite Falls DN34 16 15.1 61.39 8

Granite Falls DN34 2 3.1 0.9 3

Granite Falls DN34 3.2 4.6 2.01 3

Granite Falls DN34 4.3 5.1 2.82 3

Granite Falls DN34 5.2 5.6 4.23 3

Granite Falls DN34 6.4 6.4 7.03 3

Granite Falls NE308 3.2 4.6 1.34 3

Granite Falls NE308 4.1 5.8 2.36 3

Granite Falls NE308 5 6.3 3.9 3

Granite Falls NE308 6.8 8.2 7.68 3

Granite Falls NE308 7.6 7.4 9.7 3

Granite Falls DN182 3.2 3.9 1.89 3

Granite Falls DN182 4.1 5.5 3.38 3

Granite Falls DN182 5.2 5.1 3.96 3

Granite Falls DN182 6.7 6.9 6.94 3

Granite Falls DN182 7.5 7.1 8.93 3

Granite Falls DN17 2.2 3.5 1.02 3

Granite Falls DN17 3.9 4.5 2.62 3

Granite Falls DN17 4.7 5.6 3.22 3

Granite Falls DN17 5 5.8 4.72 3

Granite Falls DN17 6.3 6.4 7.32 3

Granite Falls DN17 19.8 18.5 112.3 10

Granite Falls DN17 20.7 18.5 124.4 10

Milaca NE387 11.4 8.5 25.19 5

Milaca NE387 10.6 8 22.66 4

Milaca NE387 9.1 7.8 15.57 4

Milaca NE387 7.4 7.2 10.05 4

Appendix 2— 

Trees harvested from central U.S. plantations by age. Tree

diameters and total tree dry weights used to establish yield tables.
25

Site Clone DBH (cm) HGT (m) Dry wgt (Kg) Tree age (yrs)

Milaca NE387 6.6 6.8 7.51 4

Milaca NE387 5.3 5.6 6.15 4

Milaca NE54 10.3 8.6 20.43 5

Milaca NE54 6.2 7.3 7.56 5

Milaca NE54 10.5 8.8 23.4 4

Milaca NE54 9.5 8.6 23.11 4

Milaca NE54 8.4 8 17.2 4

Milaca NE54 6.5 7.5 8.02 4

Milaca NE54 5.7 7.3 6.84 4

Milaca DN182 21.5 19.4 118.9 10

Milaca DN182 19.5 18.5 84.6 10

Milaca DN182 18.6 15.5 83.77 8

Milaca DN182 16.5 15.8 60.74 8

Milaca DN182 12.2 11.1 28.58 5

Milaca DN182 12 10 25.61 4

Milaca DN182 10 9.4 20.37 4

Milaca DN182 5.8 7.6 6.09 4

Milaca DN182 4.5 5.8 4.77 4

Milaca NE308 12.9 12 28.49 5

Milaca NE308 12.1 9.4 23.55 4

Milaca NE308 10.2 9 15.13 4

Milaca NE308 7.8 8 9.6 4

Milaca NE308 5.1 6.5 3.45 4

Milaca DN17 19.7 19.3 106.3 10

Milaca DN17 21 18.8 98.5 10

Milaca DN17 19.9 16 84.33 8

Milaca DN17 14.9 15.4 55.32 8

Milaca DN17 13.5 11.1 33.6 5

Milaca DN17 11.1 8.9 21.28 4

Milaca DN17 8.8 8.5 16.11 4

Milaca DN17 5.6 7.4 5.81 4

Milaca DN17 3.6 5 2.25 4

Milaca DN34 20.8 18.1 115.4 10

Milaca DN34 19.2 18.7 98 10

Milaca DN34 13.4 9.7 35.23 5

Milaca DN34 9.5 7.6 15.89 4

Milaca DN34 7.2 7.4 10.97 4

Milaca DN34 6.1 7.2 6.41 4

Milaca DN34 3.1 5 1.7 4

Milaca Siouxland 13.4 11.4 29.07 5

Sioux Falls Siouxland 7 5.4 9.87 5

Sioux Falls NE308 9 7.2 15.03 5

Sioux Falls DN182 9 7.4 16.28 5

Sioux Falls DN34 12.2 10.3 27.35 7

Sioux Falls DN34 11 10.1 21.05 7

Sioux Falls DN34 9.9 7.4 21.33 5

Sioux Falls DN17 13.6 11.1 39.04 7

Sioux Falls DN17 11.5 10.6 24.05 7

Sioux Falls DN17 9.1 7.5 16.8 5

Mondovi DN182 20.1 20.6 118.7 10

Mondovi DN182 22 20.2 133.7 10

Mondovi DN182 12.7 13.1 34.13 5

Mondovi DN182 11.1 10.3 25.61 4

Mondovi DN182 9.4 9.9 15.27 4

Mondovi DN182 5.7 7.3 5.23 4

Mondovi DN182 3.8 5.6 2.52 4

Mondovi NE308 12 12.4 36.74 5

Mondovi NE308 10.2 10.2 23.3 4

Mondovi NE308 8.6 10.6 11.79 4

Mondovi NE308 6.8 8.9 7.82 4

Mondovi NE308 4.6 7 3.04 4

Mondovi DN17 17.8 17.1 78.22 7

Mondovi DN17 16.3 16.7 64.04 7

Mondovi DN17 15.5 15.4 59.58 7

Mondovi DN17 14.3 16.2 47.87 7

Mondovi DN17 13.1 12.8 41.63 4

Mondovi DN17 10.2 9.8 20.62 4

Appendix 2—Continued
26

Appendix 2—Continued

Site Clone DBH (cm) HGT (m) Dry Wgt (Kg) Tree age (yrs)

Mondovi DN17 8.8 9 12.91 4

Mondovi DN17 5.2 8 4.6 4

Mondovi DN17 3.7 5.7 2.02 4

Mondovi DN34 20.1 21 122.8 10

Mondovi DN34 21 20 127.3 10

Mondovi DN34 16.8 14.5 68.56 7

Mondovi DN34 15.7 15.3 56.08 7

Mondovi DN34 14.6 15.7 55.96 7

Mondovi DN34 11.2 11.3 28.65 5

Mondovi DN34 9.2 9.4 18.08 4

Mondovi DN34 8.1 8.8 12.02 4

Mondovi DN34 6.1 7.4 6.1 4

Mondovi DN34 4.3 5.5 3.59 4

Mondovi Siouxland 12.3 11.9 33.01 5

Fargo DN182 14.6 11.1 46.65 8

Fargo DN182 15.2 10.8 44.68 8

Cloquet DN182 17.6 15 65 9

Cloquet DN182 16.4 15.1 60.4 9
Appendix 3— 

Biomass production in dry metric tons per hectare per year for hybrid poplar

clones DN17, DN34, and DN182 established in 1987 and 1988 at several

Midwest U.S. locations. To convert to tons per acre, multiply by 0.4461.

27

Plantations established in 1987

Ashland Fargo Granite Milaca Mondovi Sioux 

Falls Falls

Year 9 (1995) DN17 4.9 7.2 8.5 8.5 8.5 5.6

DN34 2.5 NM1 8.5 6.1 7.4 4.3

DN182 NM 7.0 NM 7.9 8.5 5.6

Year 10 (1996) DN17 NM 8.3 8.3 8.5 7.6 4.3

DN34 NM NM 9.0 6.7 7.6 4.5

DN182 NM 7.4 NM 8.3 8.1 5.4

Year 11 (1997) DN17 4.7 NM 7.6 8.5 7.6 NM

DN34 4.0 NM 9.2 6.7 7.4 NM

DN182 NM NM NM 8.1 7.6 NM

Plantations established in 1988

Ashland Cloquet Fairmont Granite Mondovi Sioux 

Falls Falls

Year 8 (1995) DN17 3.8 NM 6.5 10.1 7.2 4.7

DN34 5.2 5.2 7.4 9.2 10.1 6.7

DN182 4.9 5.6 7.6 9.0 9.4 4.7

Year 9 (1996) DN17 NM NM 6.5 9.4 7.0 4.5

DN34 NM 5.8 7.6 9.2 8.3 6.1

DN182 NM 6.3 7.6 9.0 8.1 NM

Year 10 (1997) DN17 NM NM NM NM 6.5 NM

DN34 5.2 5.4 NM NM 7.4 NM

DN182 4.9 5.6 NM NM 7.6 NM

1

NM = not measured.
28

Site Clone Number Standard Rank by Clone Rank Clone Rank/ Age (yrs)

measured deviation DBH (cm) adjusted for surv/form +

of mean survival disease

Grand Rapids, MN 1992 (2) DN5 16 4.25 15.23 DN5 15.24 DN5 121.92 7

NM6 16 2.12 15.09 NM6 15.09 NM6 120.72 7

DN182 16 3.32 12.61 DN182 12.61 DN164 85.92 7

DN55 16 2.84 12.44 DN55 12.44 DN182 75.66 7

DN17 16 1.53 11.1 DN17 11.1 DN55 74.64 7

DN2 7 2.61 10.79 DN164 10.74 DN17 66.6 7

DN164 16 1.27 10.74 NE222 10.51 NE222 63.06 7

NE222 16 2.75 10.51 DN70 8.49 DN70 59.43 7

NE264 11 1.9 9.65 DN34 8.3 DN34 49.8 7

DN70 15 2.08 9.06 NE264 6.63 NE264 39.78 7

DN34 15 2.75 8.85 I45-51 5.71 I45-51 34.26 7

I45-51 15 2.44 6.09 DN2 4.72 DN2 23.6 7

LaCrosse, WI 1992 NC5339* 16 1.8 14.13 NC5339* 14.13 NC5339* 98.91 7

DN154 14 2.55 12.13 DN154 10.61 DN17 78.56 7

DN1 14 4.87 11.79 DN1 10.31 DN154 74.27 7

NM6 8 2.57 11.78 DN174 9.82 I45-51 73.04 7

IS42.7* 10 3.87 10.97 DN17 9.82 IS31* 70.88 7

DN177 12 3.68 10.8 DN182 9.37 DN164 69.84 7

DN164 13 1.95 10.75 I45-51 9.13 DN177 64.8 7

DN182 14 1.81 10.71 IS31* 8.86 DN34 62.24 7

DN174 15 3.34 10.47 DN164 8.73 DN1 61.86 7

NM2 12 5.89 10.41 DN132 8.33 ISU107* 57.4 7

DN17 16 2.46 9.83 ISU107* 8.2 DN182 56.22 7

DN132 14 2.88 9.52 DN177 8.1 NM2 54.67 7

ISU107* 14 2.71 9.37 NM2 7.81 DN132 49.98 7

DN2 9 2.05 9.2 DN34 7.78 DN174 49.1 7

I45-51 16 2.48 9.13 IS42.7* 6.86 IS42.7* 48.02 7

IS31* 16 2.62 8.86 DN5 6.69 DN5 46.83 7

DN5 13 1.92 8.23 NE222 6.14 NE222 42.98 7

DN34 16 1.93 7.78 NM6 5.89 NM6 41.23 7

NE222 15 5.57 6.55 DN2 5.18 DN2 31.08 7

Arlington, WI 1991 DN177 12 3.34 23.13 D109* 22.75 D109* 159.25 8

D109* 4 1.76 22.75 D107* 20.575 D107* 144.02 8

DN154 8 3.15 21.94 NC5339* 17.5 DN177 138.72 8

T50 197 6 3.59 21.92 DN177 17.34 DN164 136.56 8

I45-51 6 0.98 21.82 NE222 17.11 NC5339* 122.5 8

NM2 11 5.22 20.855 DN164 17.07 NE222 119.77 8

D107* 4 2.4 20.58 D110* 16.95 D110* 118.65 8

NE222 14 2.77 19.55 NM6 16.62 DN154 87.76 8

DN182 10 3.23 19.31 NM2 14.33 DN74 78.9 8

NC5339* 15 3.06 18.67 DN74 13.15 DN70 71.4 8

DN5 9 2.17 18.59 DN182 12.07 I45-51 57.26 8

DN2 6 6.96 18.25 DN70 11.9 T50 197 41.05 8

DN164 15 2.43 18.21 DN154 10.97 DN182 36.21 8

DN34 7 2.22 17.8 DN5 10.46 NM6 33.24 8

NM6 15 3.98 17.73 T50 197 8.21 DN5 31.38 8

D110* 4 1.05 16.95 I45-51 8.18 NM2 28.66 8

DN70 12 3.02 15.87 DN34 7.79 DN34 23.37 8

DN74 14 2.11 15.03 DN2 6.84 DN17 20.84 8

DN17 6 4.3 13.88 DN17 5.21 DN2 13.68 8

Appendix 4— 

Rank (1) of hybrid poplar clones based on DBH, DBH adjusted for survival, and DBH adjusted for survival x

(form + canker). Sites are listed by age measured. Most trees were planted as unrooted hardwood cuttings.

Hard to root clones were included in 1989 through 1992 as rooted stock and are marked with an (*). Criteria

for scoring rank, form, and disease are located on the bottom of the final page of this appendix.
29

Site Clone Number Standard Rank by Clone Rank Clone Rank/ Age (yrs)

measured deviation DBH (cm) adjusted for surv/form +

of mean survival disease

Hancock, WI 1991 NM2 10 3.52 20.51 DN74 13.81 NC5339* 91.77 8

T50 197 10 1.81 18.14 DN154 13.44 T50 197 56.7 8

NC5339* 14 3.06 14.99 NC5339* 13.11 DN164 56.28 8

NM6 11 1.74 14.86 NM2 12.82 DN5 56.1 8

DN2 14 2.08 13.95 DN70 12.37 NE222 55.5 8

DN74 16 1.5 13.81 DN2 12.2 DN177 55.2 8

NE222 11 2.3 13.46 DN182 11.94 DN154 53.76 8

DN154 16 2.39 13.44 T50 197 11.34 DN2 48.8 8

DN70 15 3.38 13.19 DN177 11.04 DN182 47.76 8

DN182 15 3.21 12.73 NM6 10.22 DN74 41.43 8

DN177 11 3.4 12.62 DN17 10.02 NM2 38.46 8

I45-51 7 3.29 12.2 DN164 9.38 DN70 37.11 8

D121* 4 2.59 12.18 DN5 9.35 DN34 37 8

DN164 13 2.6 11.55 NE222 9.25 D121* 21.258 8

DN17 14 1.51 11.46 DN34 9.25 NM6 20.44 8

DN5 14 1.73 10.69 I45-51 5.34 DN17 20.04 8

DN34 14 1.62 10.57 D121* 3.04 I45-51 16.02 8

Lancaster, WI 1991 DN154 11 2.44 18.95 NM2 17.37 NE222 127.2 8

NM2 15 2.67 18.53 DN173 17.23 NM2 121.38 8

DN173 15 3.23 18.38 NM6 16.62 NM6 116.34 8

NM6 15 3.46 17.73 NC5339* 16.46 D109* 111.16 8

NE222 15 1.28 16.96 NE222 15.9 DN131 109.62 8

NC5339* 16 4.58 16.46 D109* 15.88 D113* 109.41 8

DN174 12 2.25 16.23 DN131 15.66 D193.5* 105.91 8

T50 197 14 3.07 15.94 D113* 15.63 DN34 104.3 8

D109* 4 1.75 15.88 DN38 15.19 NC5339* 98.76 8

DN74 9 5.15 15.73 D193.5* 15.13 DN21 92.05 8

DN131 16 2.17 15.66 DN34 14.9 DN154 91.17 8

D113* 4 2.58 15.63 DN70 14.49 DN38 91.14 8

DN16 14 2.24 15.62 D121* 13.98 I45-51 91.07 8

DN5 13 4.2 15.58 T50 197 13.94 DN70 86.94 8

DN70 15 3.24 15.45 DN16 13.67 D121* 83.88 8

D112* 3 2.2 15.37 DN21 13.15 DN2 83.65 8

DN38 16 1.37 15.19 DN154 13.02 DN177 83.39 8

D193.5* 4 1.39 15.12 I45-51 13.01 DN16 82.02 8

DN34 16 2.29 14.9 DN174 12.81 D112* 80.64 8

I45-51 14 1.83 14.87 DN5 12.66 DN174 76.86 8

DN177 13 3.64 14.66 DN182 12.57 DN5 75.96 8

DN1 11 2.43 14.4 DN2 11.95 T50 197 69.7 8

DN182 14 2.55 14.37 DN177 11.91 DN164 69.04 8

DN17 13 2.26 14.14 D112* 11.52 DN17 68.94 8

D121* 4 5.75 13.98 DN17 11.49 DN173 68.92 8

DN164 10 2.33 13.8 DN1 9.9 DN182 62.85 8

DN21 16 3.69 13.15 DN74 8.85 DN74 61.95 8

DN2 15 3.83 12.75 DN164 8.63 DN1 59.4 8

Appendix 4—Continued
30

Appendix 4—Continued

Site Clone Number Standard Rank by Clone Rank Clone Rank/ Age (yrs)

measured deviation DBH (cm) adjusted for surv/form +

of mean survival disease

Blackduck, MN 1991 NM2 14 1.88 11.19 DN2 10.89 D121* 75.6 8

DN2 9 1.87 10.89 D121* 10.8 DN164 75.52 8

D121* 4 1.1 10.8 NM2 9.79 NM2 68.5 8

NM6 14 2.39 10.48 DN164 9.44 DN2 65.33 8

DN164 15 0.87 10.07 NM6 9.17 NM6 55.02 8

DN17 13 3.21 9.48 DN34 8.4 DN34 50.4 8

DN34 15 3.2 9 DN17 7.7 DN17 46.2 8

DN5 12 3.5 8.67 DN5 6.5 I45-51 40.25 8

NE222 8 3.45 8.15 I45-51 5.75 DN5 39 8

DN182 11 2.71 7.76 DN182 5.34 DN182 32.04 8

I45-51 13 1.51 7.08 NE222 4.23 NE222 29.61 8

DN70 9 1.98 5.77 DN70 3.24 DN70 16.2 8

Sioux Falls, SD 1991 DN164 11 2.27 11.05 DN164 7.59 DN164 45.54 8

DN154 4 2.71 9.95 DN154 2.49 DN154 17.43 8

Belgrade, MN 1990 DN132 12 4.79 21.27 DN132 15.95 DN164 106.96 9

DN5 9 3.51 16.54 DN164 13.37 DN132 95.7 9

DN170 10 3.74 16.45 DN154 12.57 DN154 87.99 9

NE222 10 2.55 15.84 DN34 12.08 DN34 72.48 9

DN154 13 5.08 15.48 DN17 10.4 I45-51 65.52 9

DN164 14 2.52 15.28 DN170 10.28 DN170 61.68 9

DN182 10 1.44 15.16 NE222 9.9 DN70 56 9

I45-51 10 2.59 14.97 DN182 9.475 DN5 55.86 9

DN17 12 2.89 13.87 I45-51 9.36 DN17 52 9

DN34 15 2.17 12.89 DN5 9.31 NE222 49.5 9

DN2 9 3.04 12.67 DN70 8 DN182 37.9 9

DN70 12 2.38 10.67 DN2 7.125 DN2 35.63 9

NM6 7 3.6 7.43 NM6 3.25 NM6 19.5 9

Mondovi, WI 1990 DN70 3 3.31 21.47 NM2 15.26 DN170 108.32 9

NM2 12 4.07 20.35 DN154 14.99 I45-51 101.85 9

DN154 13 3.3 18.45 I45-51 14.55 DN2 94.99 9

DN2 12 3.6 18.09 DN2 13.57 DN21 94.22 9

DN170 12 3.34 18.06 DN170 13.54 DN164 92.24 9

DN21 12 3.13 17.94 NM6 13.51 DN154 89.94 9

DN182 12 4.28 17.39 DN21 13.46 NE222 87.81 9

NM6 13 3.73 16.62 DN182 13.04 DN34 85.4 9

I45-51 15 2.71 15.52 NE222 12.53 DN177 70.42 9

DN164 12 3.06 15.38 DN34 12.2 DN182 65.2 9

DN177 11 2.78 14.64 DN164 11.53 NM2 61.04 9

NE222 14 3.58 14.32 DN177 10.06 DN17 56.94 9

DN34 15 3 13.01 DN17 9.49 NM6 40.53 9

DN17 13 3.26 11.68 DN70 4.02 DN70 24.12 9

DN5 6 3.63 10.45 DN5 3.92 DN5 19.6 9

Sioux Falls, SD 1990 D110* 6 2.8 18.38 D108* 16.54 D108* 115.78 9

D108* 8 2.78 16.54 D110* 6.89 D110* 48.23 9
Appendix 4—Continued

31

Site Clone Number Standard Rank by Clone Rank Clone Rank/ Age (yrs)

measured deviation DBH (cm) adjusted for surv/form +

of mean survival disease

Grand Rapids, MN 1989 DN131 14 2.17 20.86 DN2 20.8 DN5 138.53 10

DN2 16 4.01 20.8 DN5 19.79 NM6 128.73 10

DN5 16 3.87 19.79 DN131 18.25 DN131 109.5 10

D113* 7 2.62 18.81 NM6 18.39 DN2 104 10

D125* 6 1.17 18.75 DN182 16.7 NM2 96.96 10

NM2 14 1.7 18.47 NM2 16.16 DN182 83.5 10

NM6 16 3.12 18.39 DN34 14.64 DN70 77.28 10

DN34 13 3.26 18.03 DN17 13.9 DN34 58.56 10

DN182 15 2.34 17.81 DN70 12.88 D125* 56.24 10

DN70 12 4.95 17.18 D113* 8.23 DN17 55.6 10

DN17 14 2.75 15.88 D125* 7.03 D113* 49.38 10

I45-51 3 0.75 12.93 I45-51 2.42 I45-51 16.94 10

Milaca, MN 1989 I45-51 10 3.71 16.52 NM6 15.25 NM6 106.75 10

NM6 15 3.95 16.27 DN5 14.58 DN5 102.06 10

DN34 13 2.73 14.59 DN2 14.49 NE222 84.8 10

DN5 16 3.89 14.58 DN182 14.41 DN70 72.72 10

DN2 16 2.24 14.49 DN17 12.23 DN2 72.45 10

DN182 16 3.31 14.41 DN70 12.12 I45-51 72.31 10

DN74 11 4.01 14.26 DN34 11.85 DN74 49.05 10

NM2 13 5.32 14.15 NM2 11.5 NM2 46 10

NE222 12 2.55 14.13 NE222 10.6 DN182 43.23 10

DN70 14 4.03 13.86 I45-51 10.33 DN17 36.69 10

DN17 15 3.21 13.05 DN74 9.81 DN34 35.55 10

Cloquet, MN 1988 NE295 9 3.53 20.9 DN131 15.35 DN131 122.8 11

NE49 8 3.46 20.53 NE252 15.35 NE252 122.8 11

NE33 4 2.16 19.88 DN21 14.19 DN21 113.52 11

NE54 8 4.83 19.64 NM6 13.33 NM6 106.4 11

DN131 14 2.86 17.54 DN181 12.78 DN181 102.24 11

NE252 14 2.25 17.54 NE242 12.61 NE295 82.32 11

NE265 11 2.94 16.92 NE295 11.76 NE265 81.41 11

NE222 5 7.85 16.86 NE300 11.69 DN70 77.56 11

NE242 12 2.29 16.81 NE265 11.63 NE242 75.66 11

NE300 12 3.23 15.58 DN70 11.08 NE300 70.14 11

DN70 12 5.03 14.78 NE49 10.27 NE49 61.62 11

I45-51 7 3.44 14.61 NE54 9.82 DN182 58 11

DN181 14 1.4 14.6 DN182 7.25 I45-51 51.12 11

DN182 8 2.72 14.5 I45-51 6.39 NE222 42.16 11

DN21 16 1.75 14.19 NE222 5.27 NE33 39.76 11

NM6 16 1.89 13.33 NE33 4.97 NE54 39.28 11
Appendix 4—Continued 

32

Site Clone Number Standard Rank by Clone Rank Clone Rank/ Age (yrs)

measured deviation DBH (cm) adjusted for surv/form +

of mean survival disease

Mondovi, WI 1988 DN2 9 5.33 28.08 DN70 17.59 DN70 105.54 11

I45-51 7 6.82 26.81 NE35 16.6 45-1 105.42 11

NE35 11 5.74 24.14 DN2 16.19 NE222 98.49 11

DN182 6 5.56 24.1 DN21 16.13 I45-51 93.84 11

NM6 10 5.44 23.88 45-1 15.06 NM6 89.58 11

NE222 10 5.74 22.51 NM6 14.93 NE35 83 11

45-1 11 7.71 21.9 DN17 14.81 DN2 64.76 11

DN17 11 4.38 21.55 NE222 14.07 DN21 64.52 11

DN34 8 3.92 21.2 I45-51 11.73 DN17 59.24 11

DN21 13 4.96 19.85 DN34 10.6 DN34 42.4 11

DN70 15 5.26 18.76 DN182 9.03 DN182 36.12 11

Sioux Falls, SD 1988 NE264 6 2.48 23.38 DN70 16.68 NM6 96.48 11

DN70 14 3.79 19.06 NM6 16.08 DN70 83.4 11

DN34 12 2.11 16.58 DN34 12.43 DN34 74.58 11

NE222 8 4.46 16.25 NE264 8.77 NE264 61.39 11

NM6 16 2.16 16.08 NE222 8.13 NE222 40.65 11

Fargo, ND 1987 DN2 13 3.79 19.58 DN5 16.01 DN2 111.3 12

NE222 11 3.64 17.31 DN2 15.9 DN5 96.06 12

DN5 15 3.53 17.08 NE222 11.9 NE222 71.4 12

Granite Falls, MN 1987 DN174 10 5.21 32.34 DN177 23.57 DN177 164.99 12

I476 4 6.06 32.1 DN5 22.74 DN5 159.18 12

I45-51 9 2.88 26.82 DN174 20.21 DN174 121.26 12

DN2 7 6.51 26.66 I45-51 15.09 I45-51 105.63 12

DN5 14 4.23 25.99 NM2 14.36 NE222 60.41 12

DN177 15 4.15 25.14 DN2 11.66 DN170 52.22 12

DN17 4 1.23 24.05 NE222 8.63 I476 48.18 12

DN170 5 8.04 23.88 I476 8.03 NM2 43.08 12

NE222 6 6.34 23.02 DN170 7.46 DN2 34.98 12

NM2 10 6.14 22.98 DN17 6.01 DN34 28.25 12

DN34 4 6.36 22.6 DN34 5.65 DN17 24.04 12

Milaca, MN 1987 I476 10 8.14 28.66 DN177 21.65 DN177 151.55 12

45-1 9 5.35 27.29 NM2 20.41 NE264 136.88 12

DN170 3 2.27 26.3 DN74 20.12 I476 125.37 12

DN2 11 5.38 26.25 DN2 18.05 DN74 120.72 12

NE264 11 3.64 24.89 I476 17.91 DN5 99.42 12

DN74 13 6.83 24.76 NE264 17.11 I45-51 97.58 12

DN177 14 5.72 24.74 DN5 16.57 45-1 92.16 12

DN182 9 6.77 23.34 45-1 15.36 DN2 90.25 12

DN34 10 4.02 22.47 NE222 14.77 NE222 88.62 12

NM2 15 5.39 21.77 DN17 14.76 DN1 82.86 12

DN5 13 6.77 20.39 DN34 14.04 DN34 70.2 12

I45-51 11 5.61 20.281 I45-51 13.94 NM2 61.23 12

DN1 11 2.6 20.09 DN1 13.81 DN17 59.04 12

DN17 12 6.14 19.68 DN182 13.13 DN182 52.52 12

NE222 13 5.41 18.18 DN170 4.93 DN170 34.51 12
Appendix 4—Continued

33

Site Clone Number Standard Rank by Clone Rank Clone Rank/ Age (yrs)

measured deviation DBH (cm) adjusted for surv/form +

of mean survival disease

Mondovi, WI 1987 DN182 4 1.53 27.2 NM2 22.58 45-1 141.61 12

45-1 12 5.71 26.33 DN2 21.1 DN177 127.12 12

DN2 13 4.12 25.97 45-1 20.23 NE222 103.32 12

NE264 7 2.68 24.89 DN174 20 DN170 92.33 12

I45-51 6 3.03 24.72 DN177 18.16 NE264 87.12 12

DN174 13 5.92 24.61 DN17 15.58 DN2 84.4 12

NM2 15 5.21 24.09 NE222 14.76 NM2 67.74 12

DN170 9 6.79 23.46 DN5 14.47 I45-51 64.89 12

DN177 13 5.76 22.47 DN170 13.19 DN174 60 12

NE222 11 3.64 21.47 DN34 13.18 DN5 57.88 12

DN74 10 4.68 20.91 DN74 13.07 DN34 52.72 12

DN17 12 4.39 20.77 NE264 10.89 DN17 46.74 12

DN5 12 3.5 19.29 I45-51 9.27 DN74 26.14 12

DN34 11 5.67 19.17 DN182 6.8 DN182 13.6 12

Sioux Falls, SD 1987 DN177 13 3.26 22.38 DN177 18.19 DN177 145.52 12

I476 6 4.28 21.78 45-1 14.7 DN170 95.06 12

45-1 11 4.85 21.38 DN170 13.58 NE222 90.02 12

DN170 11 4.41 19.76 I45-51 12.96 45-1 88.2 12

NE222 11 2.53 18.7 NE222 12.86 NE264 86.66 12

NE264 11 3.23 18 DN17 12.52 DN34 70.38 12

DN74 4 5.1 17.43 NE264 12.38 I45-51 51.84 12

DN34 11 2.97 17.06 DN34 11.73 DN17 50.08 12

DN17 12 3.03 16.7 I476 8.17 I476 49.02 12

I45-51 13 3.75 15.95 DN74 4.36 DN74 26.14 12

(

1

) Criteria used for scoring rank, form, and disease: 

Stem Canker Rating

4- Clean, no cankers evident

3- Light to medium cankers, no defects

2- Medium to heavy cankers, scarring

1- Dieback and breakage from cankering

Rank

1,2,3-not acceptable

4,5,6-marginal

7,8,9-higher quality, promote use

Form Rating

4- Straight clean stems with few branches

3- Slight stem sweep, medium branching, no defects

2- Crooked stems, heavy branching, minor defects

1- Stems deformed from sunscald damage and major stem defects

(

2

) Indicates the year planted.
Netzer, D.A.; Tolsted, D.N.; Ostry, M.E.; Isebrands, J.G.; Riemenschneider, D.E.; Ward, K.T.

2002. Growth, yield, and disease resistance of 7- to 12-year-old poplar clones in the north

central United States. Gen. Tech. Rep. NC-229. St. Paul, MN: U.S. Department of

Agriculture, Forest Service, North Central Research Station. 31 p.

Summarizes growth, yield, and disease resistance of 95 poplar clones at or near rotation age

(culmination of mean annual increment). Plantations were established from 1986 to 1992 in

Wisconsin, Minnesota, North and South Dakota. Clones DN164, DN177, DN154, NM2,

NE264, DN170, and DN21 are recommended for further testing.

KEY WORDS: Hybrid poplar, intensive culture, biomass yields, disease resistance, hybrid

trials.
Mission Statement

We believe the good life has its roots in clean air, sparkling water, rich soil, healthy

economies and a diverse living landscape. Maintaining the good life for generations to come

begins with everyday choices about natural resources. The North Central Research Station

provides the knowledge and the tools to help people make informed choices. That’s how the

science we do enhances the quality of people’s lives.

For further information contact:

North Central Research Station

USDA Forest Service

1992 Folwell Ave.

St. Paul, MN 55108

Or visit our web site:

www.ncrs.fs.fed.us
The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs and

activities on the basis of race, color, national origin, gender, religion, age, disability, political beliefs,

sexual orientation, and marital or family status. (Not all prohibited bases apply to all programs.)

Persons with disabilities who require alternative means for communication of program information

(Braille, large print, audiotape, etc.) should contact USDA’s TARGET Center at (202) 720-2600

(voice and TDD).

To file a complaint of discrimination, write USDA, Director, Office of Civil Rights, Room 326-W,

Whitten Building, 14th and Independence Avenue, SW, Washington, DC 20250-9410, or call (202)

720-5964 (voice or TDD). USDA is an equal opportunity provider and employer.

Printed on recyclable paper.

Pesticide Precautionary Statement:

Pesticides used improperly can be injurious to humans,

animals, and plants. Follow label directions and heed all

precautions on the labels. Store all pesticides in original

containers, out of reach of children and foodstuffs. Apply

pesticides selectively and carefully. Do not apply a

pesticide when there is danger of drift to other areas. After handling a

pesticide, do not eat, drink, or smoke until you have washed. Dispose of

empty pesticide containers properly. It is difficult to remove all traces of a

herbicide (weed killer) from equipment. Therefore, to prevent injury to

desirable plants do not use the same equipment for insecticides that you

use for herbicides.

NOTE: Some States have restrictions on the use of certain pesticides.

Check your State and local regulations. Also, because registrations of

pesticides are under constant review by the Federal Environmental

Protection Agency, consult your county agricultural agent or State extension

specialist to be sure the intended use is still registered.
North Central Research Station

Forest Service—U.S. Department of Agriculture

1992 Folwell Avenue

St. Paul, Minnesota 55108

2002

www.ncrs.fs.fed.us