20
Frank W. Davis and Dar Roberts
5300
5400
5500
5600
5700
5800
Shot Number (. 2 = appro •. dis tance in meters)
FIGURE 1.5. Profile of SLICER laser altimetry data from conifer forests in the Cascades Range in western Oregon.
The gray scale is proportional to the density of reflective surfaces in the vertical profile. Each pixel is approximately
10 m in diameter. This 600-m transect over Blue Ridge (viewer faces SW) starts in the Lookout Creek valley on the
left (the creek is in the lowest spot), continues up the south side of the ridge in mixed old-growth and mature forest,
down the north side of the ridge through a uniform plantation of 50-year-old Douglas fir, and crosses Blue River on
the right. At the top of the ridge, the dip in the ground topography is the top of Watershed 10. On both sides of Blue
River one can see 20 to 30-m-wide riparian buffers, and the road is visible on the north (right) side of the river.
(1989) describe the use of point intercept methods
for estimating foliar cover and orientation and emphasize that the approach may require very large
sample sizes to obtain reliable estimates. Stratified
clipping allows for detailed and precise measurements but is destructive and laborious. In forest, the
distortion of the canopy makes it difficult to develop accurate profiles from felled trees. Kruijt
(1989) developed a nondestructive, multiscale technique for developing vertical leaf and branch profiles based on direct measurements of sampled trees
that appears practical for relatively low-statured
forests «15 m). Cameras or probes suspended
from rope systems or cranes have also been used
to nondestructively sample the forest canopy for
vertical profiles (Koike and Syahbuddin 1993;
Parker et al. 1992).
Daughtry (1990) summarizes direct methods for
measuring leaf area and LA!. These include leaf
tracing, matching sampled leaves to standard leaf
shapes and sizes, estimation based on linear measurements, mass-based estimates, and areal measurement of harvested material using optical scanning or video planimeters. Linear measurements are
especially well suited to estimating surface area of
conifer needles, stems, and spines. For simple, planar leaves, portable optical planimeters provide
rapid, accurate estimates of LAI and are the method
of choice when a large number of samples is
involved.
Frank W. Davis and Dar Roberts
5300
5400
5500
5600
5700
5800
Shot Number (. 2 = appro •. dis tance in meters)
FIGURE 1.5. Profile of SLICER laser altimetry data from conifer forests in the Cascades Range in western Oregon.
The gray scale is proportional to the density of reflective surfaces in the vertical profile. Each pixel is approximately
10 m in diameter. This 600-m transect over Blue Ridge (viewer faces SW) starts in the Lookout Creek valley on the
left (the creek is in the lowest spot), continues up the south side of the ridge in mixed old-growth and mature forest,
down the north side of the ridge through a uniform plantation of 50-year-old Douglas fir, and crosses Blue River on
the right. At the top of the ridge, the dip in the ground topography is the top of Watershed 10. On both sides of Blue
River one can see 20 to 30-m-wide riparian buffers, and the road is visible on the north (right) side of the river.
(1989) describe the use of point intercept methods
for estimating foliar cover and orientation and emphasize that the approach may require very large
sample sizes to obtain reliable estimates. Stratified
clipping allows for detailed and precise measurements but is destructive and laborious. In forest, the
distortion of the canopy makes it difficult to develop accurate profiles from felled trees. Kruijt
(1989) developed a nondestructive, multiscale technique for developing vertical leaf and branch profiles based on direct measurements of sampled trees
that appears practical for relatively low-statured
forests «15 m). Cameras or probes suspended
from rope systems or cranes have also been used
to nondestructively sample the forest canopy for
vertical profiles (Koike and Syahbuddin 1993;
Parker et al. 1992).
Daughtry (1990) summarizes direct methods for
measuring leaf area and LA!. These include leaf
tracing, matching sampled leaves to standard leaf
shapes and sizes, estimation based on linear measurements, mass-based estimates, and areal measurement of harvested material using optical scanning or video planimeters. Linear measurements are
especially well suited to estimating surface area of
conifer needles, stems, and spines. For simple, planar leaves, portable optical planimeters provide
rapid, accurate estimates of LAI and are the method
of choice when a large number of samples is
involved.