Tree Shelters Improve the Survival and Growth of Planted Engelmann Spruce Seedlings in Southwestern Colorado

Abstract

Abstract Shade-tolerant Engelmann spruce (Picea engelmannii) is a difficult species to reforest successfully in the high-elevation spruce-fir forests of the Rocky Mountains. This study investigated the use of plastic tree shelters as a form of shade protection and a means to improve the growth and survival of planted Engelmann spruce seedlings in southwest Colorado. A total of 1500 seedlings were planted into a 48 ha clearcut site at an average elevation of 3273 m. Treatments included four different colors of tree shelters and a control where seedlings were planted using the traditional shading method. This consisted of shading the seedlings using logging slash, stumps, and vegetation within the site. After two growing seasons, survival was 58% for the control treatment and ranged from 95 to 99% in the lighter three shelter color treatments. The darkest shelter color resulted in 95% mortality after the first growing season. Both height and diameter growth of surviving seedlings were significantly greater in the lightest two shelter color treatments as compared to the control treatment. These results indicate that tree shelters may provide an effective method of improving high-elevation Engelmann spruce reforestation programs. West. J. Appl. For. 16(3):114–120.