2009-01-30_GENERAL DOCUMENTS - C1982057

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2004 Aspen Establishment Study Dr. Wayne Shepperd and Robert Musselman (Research Silviculturalist, USFS, Rocky Mountain Research Station, Ft. Collins, CO), recognized authorities on aspen regeneration and management, and SCC entered into a cooperative agreement to investigate aspen reestablishment through a series of sequential experiments to be conducted in a test plot on reclaimed ground at Seneca II-West. The objectives of this experimental test plot are to determine the feasibility of using irrigation to improve initial transplant survival, and if successful, subsequently investigate the other questions of growth and ultimate clonal reestablishment of aspen. Aspen (Populus tremuloides Michx.) reproduces primarily by root suckering in the western U.S. Although aspen produces abundant crops of viable seed, dry western climates do not provide the constant moist conditions required for seed germination and first-season growth often enough to result in reliable seedling establishment. This problem is avoided when existing aspen clones vegetatively regenerate, because the extensive pre-existing root system provides ample resources to new sprouts and nurtures them for several years until new roots can develop. Transplanting greenhouse or nursery-grown aspen seedlings into the field has similar problems to those of natural seedlings, indicating that the small root mass of transplanted seedlings is insufficient to absorb enough moisture to maintain the seedlings during periods of summer drought in the wild. In contrast, transplanting sapling-sized aspen in irrigated urban landscapes has not been a problem, because the abundant supplies of water enable the transplants to thrive. In the fall of 2004, Four blocks of 50 trees each were planted in regular topsoil and four blocks of 50 trees were planted in modified topsoil containing ground vegetation. Soil type was not randomized because of the difficulty of placement by large equipment. Instead, regular and modified topsoil were placed side by side on the slope and the study plots positioned over the two soils. The soils were placed approximately 4 feet deep over the entire study plot. Three watering treatments and an un-watered control were randomly assigned within each topsoil type. Weed control was conducted in accordance with approved mine reclamation practices, with the exception of hand spot-spraying of broadleaf weeds to avoid damage to the aspen transplants. Trees to be transplanted were selected from along the edges of successfully suckering clones on Seneca property. Aspen suckers growing at the edges of existing clones are more likely to have smaller, more independent roots than those that arise along older connecting roots between large trees. Transplant candidates were four to six feet in height, without forks, disease, or damage that might affect survival. The trees were monitored throughout 2005, 2006, and 2007 to obtain survival and growth data for comparison between watering treatments, soil handling differences, and competing vegetation effects. Results of the Aspen Establishment Study: • Best growth and survival was with low or no irrigation. • Transplanted trees from local sources produced the best growth. • Best growth and survival occurred on roto-cleared (fresh) soil compared to dozer cleared (stored) soil. • Aspen seedlings produce the most growth where competing vegetation is controlled. Study Conclusion: The best conditions for reproduction of aspen on reclaimed surface mined coal lands is obtained by using transplanted saplings from local sources on freshly placed soil, salvaged from pre-mining aspen stands. Care should be taken to avoid compaction of the replaced soil. Transplanted trees should be planted no deeper than the original root collar, and other vegetation should be controlled around individual trees. Irrigation with