Thursday, August 6, 2009: 10:30 AM
Pecos, Albuquerque Convention Center
Background/Question/Methods In early July 2002, studies in the Yunnan pine forests in the Apiladda Watershed of Baiwu Township, SW China were initiated. These studies indicated that forest stands were all less than 40-years old (i.e., likely regenerated after the clearcutting of the Great Leap Forward) and were currently being heavily utilized. In August 2008, we evaluated two anthropogenic impacts: (1) role of direct and indirect forest utilization and (2) a specific tree impact where extensive crown removal had occurred. Descriptive vegetation data, overstory and understory species composition, topography and evidence of anthropogenic disturbances, were collected during five guided walks with local elders through the study area. In total, we collected 158 data points with corresponding GPS locations along well-used, informal trail systems, encompassing a traveled distance of 65 km, and spanning 513 m in elevation (from the village of Yangjuan at 2550 m). At 30 locations on these five walks plus four other days without guides, additional data on basal area, diameter at 1.3 m, height, crown level, and increment cores from one to three trees were taken. Individual tree branch removal was assessed on dominant trees growing within 100 m of each other on similar sites.
Results/Conclusions Stand basal areas in this forest ranged from 1.4 and 1.5 m2/ha in heavily-used areas close to the villages, to 29.8 m2/ha in a hilltop stand on the ridge between the Apiladda and the Laizigou watersheds. Several stand basal areas exceeded 40 m2/ha (maximum was 48.2) and such stands were noted at higher elevations (> 2950 m) and at locations relatively far from villages and away from informal trails. Tree ages ranged between 17- and 57-years (average was 36.31±9.74SD, median = 35, n = 49). Generally as stand basal area increased (7 to 42 m2/ha), the number of stumps decreased dramatically (from 2325 to 125 stumps/ha) and stand aboveground biomass increased 15.6 to 79.2 Mg/ha. Trees with branches extensively removed versus those without had the following characteristics: 36.5±0.6 and 52.9±0.9SE % live crown, 17.7±0.5 and 21.0±0.5 cm diameter, 8.7±0.3 and 10.6±0.3 m height, and 845±49 and 854±48 mm2 average last five years basal area increment, respectively. Duff and Nolan Type II analyses demonstrated effects of branch removal on diameter growth, but rapid recovery was noted so that diameter growth was not different between treated and untreated trees. Role of recent and current human use of these forests is discussed.
Results/Conclusions Stand basal areas in this forest ranged from 1.4 and 1.5 m2/ha in heavily-used areas close to the villages, to 29.8 m2/ha in a hilltop stand on the ridge between the Apiladda and the Laizigou watersheds. Several stand basal areas exceeded 40 m2/ha (maximum was 48.2) and such stands were noted at higher elevations (> 2950 m) and at locations relatively far from villages and away from informal trails. Tree ages ranged between 17- and 57-years (average was 36.31±9.74SD, median = 35, n = 49). Generally as stand basal area increased (7 to 42 m2/ha), the number of stumps decreased dramatically (from 2325 to 125 stumps/ha) and stand aboveground biomass increased 15.6 to 79.2 Mg/ha. Trees with branches extensively removed versus those without had the following characteristics: 36.5±0.6 and 52.9±0.9SE % live crown, 17.7±0.5 and 21.0±0.5 cm diameter, 8.7±0.3 and 10.6±0.3 m height, and 845±49 and 854±48 mm2 average last five years basal area increment, respectively. Duff and Nolan Type II analyses demonstrated effects of branch removal on diameter growth, but rapid recovery was noted so that diameter growth was not different between treated and untreated trees. Role of recent and current human use of these forests is discussed.
