| Long-term changes in structure of a pinon (Pinus spp. L.)-juniper (Juniperus spp. L.) community within The Texas Nature Conservancy (TNC) Davis Mountains Preserve were evaluated by reconstructing tree temporal and spatial establishment patterns. A stratified random sampling system was utilized in which a total of 10 plots were allocated to three study sites. Increment in density of both pinon and juniper reached 422 trees ha-1 in the 115-year period between 1890 and 2005. When viewed in the context of the elapsed time, density increments of both pinon and juniper did not reflect a rapid rate of change (an annual increment of 4 trees ha-1) in this pinon juniper community.; Variation in physiographic features (i.e. slope, aspect, and elevation) indirectly resulted in variation in structure of pinon-juniper communities in which study site 414 with its relatively high elevation range, low slope inclination, and north-west aspect had the greatest overall tree density (1324 trees ha-1) and basal area (19.7 MZha-1). These variations should be taken into account in restoration efforts. In addition, restoration efforts should consider other lines of evidence (e.g. historical photographs and early historical accounts) in conjunction with stand reconstruction data in establishing reference conditions for restoration treatments. |
