UnitedStates

Depa Agrirctmuttuent reOf Guidelines For Establishing Poplar

Forest service Plantations In The North-Central U.S.

North Central

SFotation rest Experiment Edward A. Hansen, Daniel A. Netzer, and

David N. Tolsted ResearchNote NC-363

1.993 ..

_ "lh_ research is partiaUyfunded by the Delmrtment of Energy under interagency agreement DE-A105-800R20763.

ABSTRACT.---Gives guidelines for planting and SITE $_ION

•tending poplar plantations as an agricultural

crop, using intensive culture and 6- to 10-year * Select deep, fertile sandy-loam to clayrotations, loam softs with a pH between 5 and 7.5

(I}.

KEY WORDS: Short rotation, wood energy * Choose sites with a high water-holding

crops, hybrid poplar, biomass, capacity (greater than 10 inches in the top

. 60 inches of soft) or a shallow water table

Poplar trees have begun to be grown like at I to 6 feet (2).

agricultural row crops such as com or soy- * Test soft fertility, and fertfii_e according to

beans, except that these trees take 6- to 10- recommendations for com. Nitrogen is the

years to mature. Yields rm_e from 3 to 6 dry element most often deficient (3).

tons of wood plus bark per acre per year.

. Growing poplar requires thorough site prepa- SITE PREPARATION

•ration, planting of improved stock, careful and

timely weed control, and occasional fertiliza- * On fields in sod, pasture, or hay, apply

tion. This guide describes a step by step glyphosate (Roundup) and plow by July.

description how to establish a poplar planta- Leave fallow during the remainder of the

tion and refers you to additional sources of season. (Note: seed a fall cover crop,

information. It is meant to supplement advice leave vegetated strips, or use other conserfrom your local extension forester, vation tillage practices where soft erosion

is a potential problem.)

BEFORE YOU START * On fall-cropped fields, apply glyphosate if

perennials are present after harvest.

Talk to your local forester about recommended * Plow at least 10 inches deep in the fall

tree spacing and choice of hybrids or clonal (4).

p!anting stock. Tree spacing typically is 8 x 8 * Field cultivate or otherwise till 10 inches

• feet up to !0 x 10 feet, which requires 700 to deep a day or two before planting in the

400 trees/acre, respectively. Closer spacings spring.

result in shorter rotations, but rows need to be * Do not use no-till unless required for

spaced wide enough to allow equipment ac- erosion control (5).

cess.. Several poplar clones should be planted

to reduce impact of insects or diseases, but CLONAL S_ION

each clone should be in a "pure"block.

• Use only disease-resistant clones that

Edward A. Hansen is a Research Silvlcultur- have been tested over a number of years in

your locality (6}. Clones recommended at

ist, Daniel A. Netzer is a Research Forester, this time are DN-17 (Robusta), DN-34

and David N. Tolsted is a Forestry Technician (Eugenei, Imperial Carolina, etc.), DN- 182

forthe North Central Forest Experiment (Raverdeau), and Siouxland (7). Check

Station in Grand Rapids, Minnesota. with your local extension forester.
CUTTING PREPARATION * If weather prevents planting when cuttings

. are ready, cuttings can be held for weeks

Cuttings are sections of tree stems typically 10 by placing them in cold storage at 34°F or

inches long and 3/8- to 3/4-inch diameter by covering them with crushed ice (9).

with well-developed buds. They should be free

from disease and bark damage (8). I_,/_NTING

• For short-term storage prior to planting, * Plant between mid-April and early june.

keepcuttlngs sealed in plastic bags and Best time is when soft temperatures reach

store at 32 to 40°F. 50°F, or when com is being planted locally

• Warm and soak the cuttings for 5 to 10 (10).

days before planting. Make small slits in * Softs should be moist; otherwise, delay

the bag, leave cuttings in the bag, and planting until ailer rain (11).

immerse 3/4 of their length in water (8). * Keep cuttings wet while planting.

Place the cuttings in shade at 50 to 70°F. * Hand plant ushng a marked wire-core rope

Make sure buds point up. for a spacing guide, or machine plant with

• Cuttings are ready to plant when the buds a tractor driver and two planters. Hand

start elongating, showing some bright planting rates are 3 acres/day/person;

green around the bud scales, and Just machine rates are 20 acres/day/threebeforeroots begin to grow. person crew.

• Cuttings should be planted with one bud

' above the soft surface (usually about I

inch of the cutting exposed) (12). Plant

with buds pointing up.

• l-bud exposed

,.

• " " " t

i L _ " ,

- e ° . °

buds point up

• " ' / i ' ° , j

/

' • s • • .- °

" f "

' Planted cutting.

.... ' * When hand planting, push cutting into soil

• by hand if the soil is loose. If soft is firm,

_ use a dibble to make a hole and insert the

cutting. Fill any air gaps by pushing the

Cuttlngs ready for planting, soil against the cutting. Do not pack the

soil. If machine planting, be sure that soft

tilth is adequate for firm, but not excessive,

soil packing around the cutting.
FIRST-YEAR WEED CONTROL Dormant Season 

Growing Season * After fall leaf drop, apply Roundup at 1 

Ib/acre and Lorox at 2 Ib/ acre (active 

• Apply linuron (Lorox) at 1 to 2 Ibs/acre ingredients) to control perennials, winter

(active ingredient) immediately after plant- annuals, grasses, and spring germlnants.

ing or no later than when weed seed begins (Or, apply these herbicides in the spring 

germinating (13). before June 1 (14,15)). Apply herbicides

• When linuron effectiveness begins to with a small tractor or all-terrain-vehicle

decline (in 4 to 6 weeks), rotary hoe at 7- to (ATV)pulling a sprayer/trailer.

10-day intervals until trees are 1 foot tall,

or until hoebegins to cause top damage.

• After rotary hoeing, till between rows as

needed (about once a month,) with a culti- _ _

vator or 5-foot dlsc. Do not till deeper

than about 2 inches because the trees

have shallow roots. J

1-year-old plantation with good weed controL

SECOND- AND TWIRD-YEJLRWEED

• ' . " " - ".". " ' CONTROL

2-inch t£11age zone '. , . . ."

• , • .

• Delay first tillage until herbicides no

.._ ,. . . ,- longer control weeds, then disc as neces-

.. , , ,,. ' sary (two to three times a summer}.

" Keep tillage shallow (less than 2 inches)

" , -- ,'. ,- to minimize root pruning.

,. • , " • ". ,, • * Apply Poast if grasses invade tree rows.

• . • ' * Apply Roundup and Lorox after fall leaf

• , I + . ' •

•"' " " i. . drop as prescribed for first year.

• . .

, 0 l ° . •

o •

• a" " • •,

• .,

.- . "- - . • FOURTH-YF..AR WEED CONTROL

• s ot o .o o .

If you used good cultural practices during the

Growing cutt/ng, first 3 years, the trees should be shading out

the weeds by the fourth year, reducing or

• If annual grasses invade the tree rows, eliminating the need for weed control. If some

apply Sethoxydem (Poast) at I pint/acre weed control is necessary, use practices

before grasses are 5 inches tall. Use only prescribed for the second and third years.

vegetable off concentrate or none at all; do

nOt use petroleum-based concentrates. FERTILIZATION

All broadleaf herbicides will damage

growing trees. * Maintain leaf nitrogen content above 3.0

percent. Sample the uppermost fully

expanded leaves on the terminal shoot in

3
late June to determ/ne N status. When * In certain geographical areas, Surflan or

samples are consistently lower than 3 Goal may prov/de better annual weed

percent, apply N at 150 Ibs/acre. control than Lorox.

• Perenn/al quackgrass/nvad/ng during the

HARVEST grow/rig season can be controlled w/th

Fusflade applied in a split appl/cat/on of 16

• Harvest the plantation when average oz and 8 oz per acre before the grass is 6

annual growth begins to decline; your local inches tall.

forester can adv/se you when this beg/ns to * If cottonwood leaf beeries/nvade, apply

happen, Malath/on at 16 oz/acre (6}.

• Contact YOUrlocal forester for/v.format/on * Clean culUvaUon and a weed-free border

about harvest/ng methods, contractors, around the plantaUon will keep populaand the market. Uons of rodents (m/ce, rabbits, gophers)

from/ncreas/r_ to the point of caus/ng

•POST-HARVEST OPTIONS widespread damage. Browsing by deer is

generally confined to edge trees. Most

• Replant w/th new improved stock (faster trees grow above the browse zone dur/ng

grow/ng, disease resistant), the second grow/ng season (17).

• Retain plantation w/th coppice (stump

sucker)-regrowth. A coppice cycle will be a SOME FINAL COMMANDMENTS

few years shorter than the first rotation.

Do not th/n coppice clumps unless you Soak an_l plant cuttings with buds

want s/ngle-stem trees; th/nr_ng does not pointing up.

result in greater growth of the dominant Deep plow for site preparation.

stem, and it may reduce total yields (16). Till shallow for weed control

Keep weeds outllllll

• OTHER THINGS TO CONSIDER

• If you want s/r_le-stem trees, remove

multiple stems W/th a shears during the

first fall or w/nter.
REFERENCES I0. Hansen, Edward A. 1986. Planting date affects

° survival and height growth of hybrid poplar. Forestry

I. "Foisted' David N. 1988. Liming soils above pH 5.2 Chronicle. 62(3): 164-169.

does not increase Popu/us growth. Res. Note NC-344.

St. Paul, MN: U.S. Department of Agriculture, Forest 1I. Hansen, Edward A." Phipps, Howard M. 1983. Effect

Service, North Central Forest Experiment Station. 2 p. of soil moisture tension and preplant treatments on

early growth of hybrid Popu/us hardwood cuttings.

2. Hansen, Edward ,_ 1988. Irrigating short rotation Canadian Journal of Forest Research. 13: 458-464.

intensive culture hybrid poplars. Biomass. 16{4}: 237-

250. 12. Hansen, Edward: Tolsted, David: Tower, Matthew.

1991. Planting depth of hybrid poplar cuttings

3. Hansen, Edward A.; McLaughlin, Richard A.; Pope, influences number of shoots. Res. Note NC-355. SL

Phillip E. 1988. Biomass and nitrogen dynamics of Paul, MN: U.S. Department of Agriculture, Forest

hybrid poplar on two different soils: implications for Service, North Central Forest Experiment Station. 4 p.

fertilization Strategy. Canadian Journal of Forest

Research. 18(2): 223-230. 13. Hansen, Edward A.; Netzer, Daniel A. 1985. Weed

• control using herbicides in short-rotatlon intensively

4. Harisen, Edward; Netzer, Daniel; Rietveld, W.J. 1984. cultured poplar plantations. Res. Pap. NC-260. St.

Site preparation for intensively cultured hybrid poplar Paul, MN: U.S. Department of Agriculture, Forest

plantations. Res. Note NC-320. St. Paul, MN: U.S. Service, North Central Forest Experiment Station. 6 p.

Department of Agriculture, Forest Service, North

Central Forest Experiment Station. 4 p. 14. Danfleld, William I_; Martishus, James; Hansen,

Edward A. 1983. Application date affects herbicide

5. Hansen, EJL; Netzer, D.A.; Woods, R.F. 1986. Till tolerance ofhybrid poplars. Res. Note NC-301. St.

superior to no-till for establishing hybrid poplar Paul, MN: U.S. Department of Agriculture, Forest

plantations. Tree Planters' Notes. 37(I): 6-I 0. Service, "North Central Forest Experiment Station. 4 p.

6. Ostry, Michael E.; Wilson, Louis F.; McNabb, Harold 15. Netzer, Daniel; Hansen, Edward. 1983. Controlling

S." Moore, Lincoln M. 1989. A guide to insect, disease weeds in poplars by dormant season glyphosate

and animal pests of poplars. Agrtc. Handb. 677. overspray. In: Proceedings, North Central weed

Washington, DC: U.S. Department of Agriculture, control conference; 1983 December 6-8; Columbus,

• Forest Service. 118 p. OH. Ames, I_ Iowa State University; 38: 141-142.

7. Hansen, E. 1992. Mid-rotation yields ofbiomass 16. Druck, Norman; Strobl, Silvia. 1991. Type and timing

plantations in the north central United States. Res. of thinning hybrid poplar coppice affects growth.

Pap. NC-309. St. Paul, MN: U.S. Department of Northern Journal of Applied Forestry. 8: 166-168.

Agriculture, Forest Service, North Central Forest

Experiment Station. 8 p. 17. Netzer, Daniel A. 1984. Hybrid poplar plantations

outgrow deer browsing effects. Res. Note NC-325. St.

8. Dickmann, D.; Phipps, H.; Netzer, D. 1980. Cutting Paul, MN: U.S. Department of Agriculture, Forest

diameter influences early survival and growth of Service, North Central Forest Experiment Station. 3 p.

several Popu/us clones. Res. Note NC-261. St. Paul,

MN: U.S. Department of Agriculture, Forest Service,

North Central Forest Experiment Station. 4 p.

9. Phipps, Howard M.; Hansen, Edward ._; Fege, Anne S.

• 1983. Preplant soaking of dormant Popu/us hardwood

cuttings. Res. Pap. NC-24 I. St. Paul, MN: U.S.

Department of Agriculture, Forest Service, North

Central Forest Experiment Station. 8 p.

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Pesticide Precautionary Statement

This publication reports research involving pesticides. It

does not contain recommendations for their use, nor does it

imply that the uses discussed here have been registered. All

" uses of pesticides must be registered by appropriate State

and/or Federal agencies before they can be recommended.

Mention of trade names does not constitute endorsement of

products by the USDA Forest Service. Other products may

be equally effective. Always read and follow label directions.

CAUTION: Pesticides can be injurious to humans, domestic

animals, desirable plants, and fish or other wildllfe--if they

are not handled or applied properly. Use all pesticides

selectively and carefully. Follow recommended practices for

• the disposal of surplus pesticides and pesticide containers.

The policy of the United States Department of Agriculture

Forest Service prohibits discrimination on the basis of race,

color,national origin, age,religion,sex_ordisability.

Persons believing they have been discriminated against in

any Forest Service related activity should write to: Chief,

Forest Service, USDA, Washington, DC 20250.

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_, U.S.. GOVERNMENT PRINTING OFFICE: 1993--756-794