The hip chain is a useful tool for measuring distances over rough or uneven terrain. As they walk, the string is pulled through a counter that measures the distance travelled leaving hands free to hold a clipboard, compass, GPS, etc. The problem with hip chain thread is also its greatest advantage. The string has to be strong enough so it doesn't break when it goes over and around rocks, brush and logs. Manufacturers use biodegradable cotton string, but decomposition rates vary.
Foresters find hip chain particularly useful when working alone in the bush.
I work both as a professional forester and professional biologist, and work with foresters, biologists, agrologists, hydrologists, engineers, and resource planners, among others in the day to day field of forest management. The practice of forest management is no longer strictly conducted by foresters. In fact, the Foresters Act is somewhat dated. Some of the best forest management planning and practice that I have been involved in was the result of good public accountability and a multi-discipline professional team approach. Consensus decision making at LRMP tables is such an example.