Mulches for Tree Planting

Mulches are an effective alternative to herbicides and mechanical cultivation for protection of tree and shrub seedlings from competition with weeds for moisture and nutrients. Placed on the soil around the seedling, they improve growth and survival by preventing other plants from germinating or growing.

Mulches protect plants from dry conditions by trapping moisture beneath them and minimizing evapotranspiration.

Mulches reduce wind erosion in tree rows and prevent crusting of the soil surface.

Organic and Plastic Mulches

There are two kinds of mulches - organic and plastic. Organic mulches are loose materials such as wood chips, straw, flax shives or bark. These mulches have been used for years to control weeds and conserve moisture. They can be difficult to obtain in large quantities and application is often laborious. In most cases, soil temperature is cooler under these mulches.

Plastic mulches are sheets or rolls of plastic that are laid on the ground around the trees. They effectively prevent weed germination and are normally easier to apply than organic mulches. Plastic mulches increase and maintain soil temperature. Some plastic mulches are designed to both retain water and allow excess water to evaporate.

Mulches help seedlings grow by increasing the temperature of the soil and holding the heat during cool evenings. They can also protect plants from extreme hot and cold temperatures.

Mulches can reduce losses from soil-borne diseases by preventing fruit and plants from becoming mud splashed.

CHOOSING A MULCH

Lifespan - Mulches should last a minimum of three years. Organic mulches may need to be replenished occasionally. Plastic mulches should have U.V. inhibitors to delay break down from sunlight.

Type of Planting - Roll mulches are more effective for extensive plantings such as field shelterbelts and wildlife plantings. For farmstead and ornamental trees, individual sheet mulches may be the best choice.

Application - Mulches should be easy and inexpensive to apply. Preferably they are applied when trees are first planted.

Cost - Mulches are generally more expensive than herbicides. For example, herbicide application costs about $100/mile annually (three applications/year) compared to $300/mile for plastic. If available, organic mulches ie. flax shives can often be obtained at no cost.

TYPES OF MULCHES

Impermeable Plastic

The mulch is applied over newly planted seedlings using a mulch layer. These applicators can be purchased at a cost of $1200 - $1800. Seedlings are pulled through slits cut in the plastic. The mulch is pinned to the ground at each seedling using staples or a rock (do not use clumps of soil). The slit should be large enough so that the seedling does not rub against the plastic.

Suppliers:
Jeffries Nursery PORTAGE LA PRAIRIE, MB. Phone: (204) 857-5288 Fax: (204) 857-2877	Inovative Plastics Marketing (1992) Ltd. 11535 - 160th Street EDMONTON, AB. T5M 3V8 Phone: (403) 454-8162
Plasti-Tech 478 Rue Notre-Dame ST. REMI, Quebec J0L 2L0 Phone: (450) 454-3961 Toll free: 1-800-667-6279 Fax: (450) 454-6638

Permeable Woven Plastic

Mulch is applied using the same methods as for impermeable plastic.

Plastic Squares

The plastic is applied by placing the hole in the centre of the square over the tree seedling. The mulch is secured to the ground using six inch long metal staples. The first staple is inserted in the centre of the mulch, and then the corners are pulled tight and pinned down.

Suppliers:
Brush Blanket® Arbortec Industries Site 33, Comp 21 R.R.1 PENTICTON, B.C. V2A 6J6 Phone: 1-800-561-9888 Fax: (604) 493-3666	Weed Mat® Canadian Forestry Equip. Ltd. 17309-107 Ave. EDMONTON, AB T5S 1E5 Phone: 1-800-661-7959 Fax: (403) 484-6783

Cellu Fib®

Cellu Fib® is applied by folding the corners over and pinning them to the ground with staples. The slit extends from the centre to the outside edge of the sheet. To prevent weed growth in areas where weeds are a severe problem, a small piece of Cellu Fib® is stapled over the slit.

Suppliers:
Casccades Multi-Pro Inc. 1 Place Ville-Marie Bureau 3615 MONTREAL, PQ H3B 3P2 Phone:(514) 393-2611

Wood Chips

Chips are normally applied by hand to a depth of five to 10 centimeters. To reduce rodent damage keep the chips about 10 centimeters from the base of the tree. Do not use more than 10 centimeters of chips as this will reduce root development and the amount of air getting to the soil. Occasionally wood chips will need to be replenished. On nutrient poor soils decomposing wood chips can cause nitrogen deficiency. If this occurs (seedlings have pale yellow-green leaves or needles), treat the seedlings with nitrogen fertilizer. Do not use wood chips until they have aged for at least six weeks.

Suppliers:
Urban municipalities and Tree service companies

Flax Shives

Flax shives are applied over seedlings to a depth of 10 centimeters by hand or mechanically with a modified manure spreader or bunk feeder. To prevent rodent damage leave about 10 centimeters between the base of the tree and the shives. Do not apply more than 10 centimeters of shives as this will restrict soil aeration. After 30 to 50 days the shives will consolidate and a crust will form on the surface.

If nutrient deficiencies occur seedlings should be treated with nitrogen fertilizer. This normally occurs only on nutrient poor soils.

Suppliers:
Local farms; Flax straw processing companies

Slough Hay

Slough hay is applied at a depth of 10 to 15 centimeters. It is initially loose but will consolidate quickly. Unlike straw, once consolidated it remains intact and will not blow away. With all hay mulches introduction of weed seeds may be a problem.

Slough hay is normally applied by hand. Do not cut slough hay until waterfowl nesting is over.

Suppliers:
Local farms

TIPS FOR MULCH APPLICATION

1. Apply mulches to weed free soils.
2. Ensure plastic mulch edges are properly secured.
3. Apply mulches as soon as possible after trees are planted.
4. Remove debris (large rocks, stumps, etc.) before laying mulches.
5. Organic mulches should be applied as evenly as possible.
6. Inspect the mulch routinely. Replace or repair torn or ripped mulch. Replenish organic mulches as required.
7. Rocks or staples placed at each seedling secures plastic mulch and directs runoff to the seedling.
8. Consider mowing or spraying of weeds along edge of mulch.
9. You may wish to plant a non-competitive grass between rows of trees that have been mulched.

MECHANICAL MULCH APPLICATION

Mulches are applied over newly planted seedlings. A small slit is made in the plastic at each seedling. Keep the opening small to optimize weed control, but ensure slit is large enough that the plastic does not rub against the tree. A rock or staple should be used to secure plastic at each tree. The applicator secures the mulch by rolling dirt over the edges of the plastic. The plastic is kept tight and the edges packed to keep the mulch in place.

Applicator Suppliers:
Buckeye Tractor Co. P.O. Box 123 COLUMBUS, Ohio 45830 USA Phone: (419) 659-2162 Fax: (419) 659-2082	Plasti-Tech 478 Rue Notre-Dame ST. REMI, Quebec J0L 2L0 Phone: (450) 454-3961 Toll free: 1-800-667-6279 Fax: (450) 454-6638
Holland Transplanter Co. 510 E. 16th st. P.O. Box 1527 HOLLAND, MI 49422-1527 USA Phone: (616) 392-3579 Fax: (616) 392-7996	DeWitt Products 2916 Tulane Dr. FORT COLLINS, Colorado 80525 USA Phone: (303)225-1912 Fax: (303) 225-0167

For more information contact: