Will Jaremko-Wright, New Mexico Highlands University, Department of Natural Resources Management, email@example.com (Presenter)
PiÃ±on-Juniper woodlands of the southwest have been experiencing both geographic and population expansions throughout the vegetation types range. In New Mexico, stands of one-seed Juniper (Juniperus monosperma) and less commonly two-needle PiÃ±on (Pinus edulis) have been observed encroaching into previously non-woodland areas, specifically in the mesa, valleys, and highland plains region of northeastern New Mexico (MLRA 70A, 70B, 70C). Expansion of PiÃ±on-Juniper extends further into adjacent plant communities across the landscape in regeneration waves characterized by stands with distinct age structure or characteristics. Source stands of older, pre-settlement trees, likely occurs in fire refugia sites with the newest â€˜wavesâ€™ found with increasing distance in mesic, lower landscape positions. Landscape gradients associated with topographic positions and site quality of PiÃ±on-Juniper stands were investigated as potential explanations for observed encroachment dynamics. Stand age structure, relative growth rate, and fine fuel loads were collected and analyzed against the topo-edaphic features of the site. Variations in one-seed Juniper sex ratios in response to environmental conditions along a gradient of decreasing stress was also investigated as a potential mechanism in Juniper encroachment feedback processes. Preliminary results are presented and discussed here. This research continues the efforts to better understand PiÃ±on-Juniper expansion across landscapes and to develop sound information for management decisions and directions.