Tree Facts: Pros and cons of weed control fabric
Weed control fabric is made of strands of black polypropylene fabric tightly-woven like burlap. It is used as a method of reducing competition from grass and weeds and conserving moisture for tree seedlings especially in shelterbelts. The use of weed control fabric increases the cost of tree plantings considerably and poses some management/maintenance considerations. However, it can improve survivability and growth of tree seedlings during drought cycles, in sandy soils, on upland sites, and on naturally arid sites thereby reducing replanting costs.
It is very important to protect newly planted tree seedlings from competition for at least four years. Weed control fabric will keep competing vegetation away from the trees. Without fabric, competition must be controlled by spraying herbicides and/or tillage several times during each growing season.
Weed control fabric originally was thought to decompose after approximately five years; however it is not uncommon for it to be almost as good as the day it was laid down after 10-20 years. As trees and shrubs grow in diameter they can begin growing over the fabric, eventually, girdling and killing them. To prevent these problems it is recommended after 5 years or so to cut the fabric back away from the plant stem so it has more room to grow. A homemade tool for this can be made, by fastening a box cutter to the end of a long stick, broom or shovel handle.
The use of weed control fabric has advantages and disadvantages. The advantages include the following: applied only once, increases chances of survival and establishment, increases growth rates immediately following planting, easier, more timely and longer lasting weed control and comparable cost to other weed control methods when averaged over 5 to 10 years. The disadvantages include the following: initially expensive, requires special machinery and trained crew to install, proper installation is critical to avoid air pockets and to prevent wind from unraveling it, doesn’t breakdown and disintegrate, trees may be girdled and killed, suckering of shrubs is restricted and dense sod can become established on top of fabric complicating future maintenance.
Weed control fabric requires management. It should be inspected at least annually to ensure that the edges are firmly anchored, ensure that the openings are not damaging the trees, to keep soil and organic matter off of fabric, to control aggressive weeds that may establish in fabric openings and to enlarge openings as needed to prevent stem girdling.
Weed control fabric has greatly increased tree planting success and vigor in conservation plantings but it is not trouble free. You cannot have the trees planted, weed control fabric laid and never go back. Regular maintenance is needed in order to achieve optimum growth and survival. In addition to maintenance grass and weeds between the rows need to be mowed several times during the growing season to reduce competition to the tree seedlings. Tillage can be done instead of mowing but can cause damage to the fabric or roots of the seedlings. Since fabric can inhibit suckering of some shrub species, another weed control method may be more appropriate for certain types of plantings.
My sources for this news release were the USDA Natural Resources Conservation Service and SDDA Division of Resource Conservation and Forestry. If you would like more information about weed control fabric, contact Natalie Euler at the Conservation Office at 605-244-5222, Extension 4 or by e-mail at firstname.lastname@example.org.