Description
Used anchor chains are commonly utilized in revegetation for tree felling, smoothing of disturbed land (e.g. rootplowing), and/or seedbed preparation. Chains are sized by the diameter of the round stock, and sizes range from 1 to 6 inches. Revegetation projects normally use chain sizes between 2 and 3 inches. Within this range, individual links are 12 to 18 inches in length and weigh between 25 and 86 pounds. The resulting weight per foot of chain is about 37 to 88 pounds, respectively. Anchor chain is usually sold in 90-foot lengths called “shots.” Further specifications on weight and link size are listed in Appendix.
Application
Anchor chains are pulled in a “U” shape between two crawler tractors. The distance between the two tractors depends on the force required to pull the chain. An initial distance of 1/3rd the length of the chain is a rule-of-thumb. Size and length of the chain are factors as well as the size of the tractors. The distance between tractors can be greater when preparing a seedbed than when felling trees. Chain length is usually between 200 to 400 feet. Length can be adjusted easily with standard cutting and welding tools. Crawler tractors used for chaining vary from 140 to 350 horsepower. Production rates vary widely between 10 and 70 acres/hour. Chaining a second time in the opposite direction increases the effectiveness of removing tree stumps and can be useful in increasing soil disturbance for seeding (see Anchor Chains and Modified Chains sections of Site Preparation). Chaining is not effective on trees with limber trunks. Chaining is very cost effective especially on large areas. It is more effective when combined with raking, herbicides, or fire to control sprouting shrubs.
Used anchor chain can be purchased from marine supply or salvage companies located in coastal cities of the United States.
Images
References / Additional Information
Roby, G.A.; Green, L.R. 1976. Mechanical methods of chaparral modification. Agric. Handbook 487. U.S. Department of Agriculture, Forest Service. 46 p.
Stevens, R.; Monsen, S.B. 2004. Chapter 9. Mechanical plant control. In: Monsen, S.B.; Stevens, R.; Shaw, N.L., comps. Restoring western ranges and wildlands, vol. 1. Gen. Tech. Rep. RMRS-GTR-136-vol-1. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station. p. 65-88.