Change in vegetation patterns over a large forested landscape based on historical and contemporary aerial photography.

摘要: Changes to vegetation structure and composition in forests adapted frequent fire have been well documented. However, little is known about changes the spatial characteristics of these forests. Specifically, patch sizes detailed information linking type specific locations growing conditions on landscape are lacking. We used historical recent aerial imagery characterize patterns assess contemporary change from those patterns. created an orthorectified mosaic photographs 1941 covering approximately 100,000 ha northern Sierra Nevada. The imagery, along with 2005, was segmented into homogenous patches classified four relative cover classes using random analysis. A generalized linear mixed model compare topographic associations dense forest landscapes. amount increased 30 43% replacing moderate as most dominant class. Concurrent increase extent, area-weighted mean size tenfold, indicating greater continuity more across landscape. Historically, rare southwesterly aspects, but forest, it common a broad range aspects. Despite challenges processing air photographs, unique they provide makes them valuable source reference for impacted by past management practices.