Plant-Soil Feedbacks and Subalpine Fir Facilitation in Aspen-Conifer Forests

摘要: Plant-Soil Feedbacks and Subalpine Fir Facilitation In Aspen-Conifer Forests Joshua R. Buck Department of Plant Wildlife Sciences, BYU Master Science This thesis includes two studies. First, changes in soil characteristics resulting from prolonged conifer dominance successional aspen-conifer forests were studied. The primary objective this paper was to identify how increasing that develops later stages alters forest characteristics. Soil measurements collected along a stand composition gradient, which the range conditions exists through secondary succession forests. chemistry, moisture content, respiration, temperature measured. There consistent trend aspen stands demonstrated higher mean nutrient concentrations than adjacent meadows, mixed or stands. significantly meadows early summer. respiration throughout results indicate resource availability peak within dominated are present during then decrease as abundance increases our representative mid late stages. second study examined facilitation effect between subalpine fir establishment. We have observed general establishment seedlings at base trees forest, indicating facilitative relationship may exist. seeds planted across gradient six sites Fishlake National Forest. Seeds placed fall 2010, distances 0cm 25cm each cardinal direction mature type. also interspaces meadows. Seedling emergence, mortality, content measured positions following Aspen had germination on average 11 times greater other types. Germination 2.3 fold interspaces. mortality lower but not influenced by position relative trees. highest stands, with better compared Few if any studies regarding provided evidence for life stage, rather they focus seedling survival. However, illustrates strong interaction both increase likelihood drastically rates germination.