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ASPEN REGENERATION STUDY (1986 PROGRESS REPCRT) INTRODUCTION: ~~~EOV~~ ~dAY 0¢ 1967 MINED LANb CIECLAMATION DIVISION This report contains the first years results of Colorado Yampa Coal Company's (CYCC) Aspen regeneration study. As part of CYCC's wildlife mitigation plan for the Little Middle Creek Tract (LMCT) they are conducting a study to test several treatments with potential for improving Aspen establishment and survival on livehandled topsoil. Aspen is the dominate vegetation type on the LMCT. Previous studies and monitoring conducted at CYCC have shown that live-handed topsoil without any additional seeding is a valuable technique for improving native plant establishment, particularly shrubs. Shrub densities on live-handled sites have proven superior to those on seeded sites. Aspen is initially one of the woody species that sprouts on live-handled sites. However, aspen does not persist as well as many of the other shrub species. Observations, and discussions with USFS Aspen experts indicate a number of potential problems. The factors which seem most likely for the decline of aspen on live-handle sites are browsing by big game, root size of aspen in live-handled topsoil and moisture. Browsing by deer and elk on CYCC reclamation occurs through out the summer and is particularly heavy during spring and fall. Extensive elk studies/tee at CYCC show that 150-200 elk use the mine during the summer and as (nAy) as 1000 elk migrate across the mine spring and fall. Although extensiv study has not been done on deer, they are a common sight on reclamation throughout the summer. Small aspen seedlings sprouting from chopped root segments in live-handled topsoil do not have estab]ished root systems. As a result any amount of browsing can exhaust the remaining carbohydrate reserves for resprouting and establishment. Average annual precipitation on the LMCT is between 16 and 20 inches. This is the low end for aspen habitats. As a result desication of young seedlings could be a major cause of aspen mortality Browsing and competition from grasses (which are very productive on live-handled sites) could be contributing to the water stress for the seedlings. Taking into account the above information, several treatments were designed to test their effectiveness on improving aspen survival on live-handled topsoil. Most of CYCC's live-handled toy sail is currently treated with a Madge-Rotoclear prior to moving the topsoi Y This machine is pulled by a dozer which knocks down the trees and existing vegetation which are then chopped up by the Mad e-rotoclear and incorporated into the topsoil. This has been very eff~tive in providing a natural mulch and incorporating organic matter that-other wis be removed and lost. However, it was felt that the Madge-rotocleal-' ma be reducing the size of root seg ents in live-handled topsoil. As a res lt, poor sprouting or survival maybe occurring. There is evidence that increased disturbance to aspen roots reduces sprouting. Therefore, one treatment consisted of comparing rotocleared topsoil with topsoil which has not been rotocleared. Non-rotocleared topsoil would have the trees dozed off and then would be live-handled. Another treatment consisted of moving topsoil in 1 li~'t verses 2 lifts. When 2 lifts are used the top 16 to 18 inches for rotocleared sites and 10 to 12 inches for dozed sites are removed seperately from the