Large sitka spruce (Picea sitchensis) trees with complex crowns provide canopy habitat, but the extent of is drastically reduced from historical levels from past logging. Canopy habitat enriches landscape-level biodiversity and structure. Conversion from old forests to young stands decreased canopy habitat on the landscape. Canopy habitat is supported on large appendages that accumulate litter, epiphytes, and the organisms that use them. The rate of appendage development likely depends on age and competition for light with other trees. To reestablish tree-crown complexity in younger stands, we must understand timeframes for appendages to reach critical sizes and how this rate is influenced by forest density. How old are large appendages in sitka spruce and what tree-tree distances influence the size of tree crowns? A sample of 36 trees were selected stratified by tree height and forest density. From one field season, 16 trees from a broad range of height (60-97m), forest density (17m2/ha-93m2/ha), and ages (100-300 yrs) were climbed and mapped in detail. Increment cores at multiple heights estimated ages of appendages, and 25 meter radius ground plots around each tree. Tree positions and crown projections from LiDAR were used for landscape level analysis.
Results/Conclusions
Preliminary results show increasing numbers of appendages and habitat surfaces increase with tree age, and the height of habitat related structures increases with increasing forest density. Additionally, increasing forest density and tree height of neighbor trees are negatively associated with tree crown size, and may influence tree crown size up to do distances of 10 m. We discuss further analyses to identify thresholds tree-tree distances that may directly effect in the number of habitat-related structures.