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Canopy hits are then classified into
vertical profile bins above the ground. Camp
Ripley data was binned into 1 meter vertical
profiles (Figure 8-for illustration purposes
this image shows binning into 10 3m bins).
The number of hits were then tallied for
each bin, including the ground hits, to
derive the proportion of hits falling within
each vertical height bin. These are then
expressed as proportions of the total hits
within a designated cell size (canopy
closure was defined in both 10m and 50m
cells). The information in these vertical bars
were then used as explanatory variables to
model and estimate forest metrics. For more
information on the statistical models used refer to Restani and Newton (2009).
Canopy cover results can be displayed as a vertical canopy profile (histogram), where the
sum of the bars equals 100%, including the ground hits (Figure 9). By examining these bars and their
magnitudes we can visualize what the forest stand within a cell will look like.
Figure 9.
Figure 8.
In addition to the binned canopy closure values,
the canopy cover data set contains X and Y coordinates
for the center of each cell. With these centroids a raster
layer with the appropriate cell size can be generated and
the cells can be populated with the associated canopy
cover values. This provides another method for
displaying results. Figure 10 shows total canopy cover,
however individual vertical profiles, or a combination of
profiles, could also be displayed. These raster layers can
then be used for spatial analysis within a GIS.
In the spring/summer 2009, an assessment was
conducted on 40 bird plots and 40 random points across
multiple land cover types to evaluate the accuracy of forest metric estimates. A wandering quarter
method was used to select trees randomly in each of four quadrants (NE, NW, SW, and SE)
beginning from the plot center. Trees were defined as stems ≥ 10 cm dbh with saplings defined as
stems < 10 cm dbh. Trees and saplings were sampled separately for dbh (m), canopy height (m), and
ground-to-live canopy height (m) (trees only), as well as distance to nearest neighbor (m), which will
allow for estimation of stem densities within each plot.
Page 19
2009 Conservation Program Report