Abstract:
Black bear bark stripping in redwoods is a threat to commercial timber production
because of the detrimental effects on redwood tree health. The purpose of the study was
to delineate vegetation characteristics of redwood plots at the black bear bark stripping
sites at Schatz Demonstration Tree farm. FUSION, an open-source, spatially explicit,
remote sensing software developed by the Silviculture and Forest Models Team of the
US Forest Service was used to calculate a few forest-stand metrics. The main research
question being asked is whether Lidar (Light Detecting and Ranging) derived forest
metrics combined with LDV are useful to detect and isolate the bark-damaged redwood
trees among healthy trees. FUSION allows visualization of Lidar data in the Lidar Data
Viewer (LDV), and batch processing allows calculation of both individual tree and
grid-based metrics within plots. Field visits were made to identify patterns and possible
causes of bear bark stripping on redwood trees, and GPS points were collected from
damaged trees. To work with FUSION, a bare earth model was created using a digital
elevation model to display a contour map over an Orthophoto. Three plots with dead
redwood, stripped and recovering redwood, as well as stripped and resprouting redwood
were displayed using a small stroked-circle sampling method. Histograms were
visualized in the LDV to distinguish high-intensity values for natural features such as
vegetation and low-intensity values for features like wet and bare soil. Simple
measurements of bare earth elevation and treetop height within plots were taken using
Lidar point cloud data and visualized in the LDV window. Batch processing was
performed to extract point cloud data within each plot using the Clipdata algorithm and
then plot statistics were computed using the Cloudmetrics algorithm. Lastly, the
Gridmetrics algorithm was used to generate a landscape-wide canopy cover raster. The
results showed that the dead secondary-growth redwood plot has 73 % canopy cover,
while the stripped and recovering, plus the stripped and resprouting plots have 95% and
78% canopy cover respectively. The dead secondary-growth redwood plot has the
tallest trees (60 m ±7.6) compared to the stripped and recovering (48 m ±8.4) and
stripped and resprouting (41 m ±7.7) plots. In conclusion, calculating Cloudmetrics for
each bear damage site, silviculturally managed sites, and undamaged sites would be
valuable to understanding the structural characteristics of vegetation and their effects on
black bear bark stripping-induced stress on redwood trees. Plot data and site
Proceedings of the 12th Annual Science Research Session, FAS, SEUSL, 14th December 2023
characteristics are vital to integrate with Lidar data matrices for insight the impact of
black bear bark striping on conifer forests.
