144
Remote Sensing Applied to Ecosystem Management
0%
50%
100%
FIGURE 10.3. Percent forest cover area per square kilometer for the conterminous United States.
enced by latitude, continental position, and elevation. Vegetation macrofeatures determine where divisions are broken into provinces. A VHRR data are
a good choice for assessing ecosystems at these levels. The A VHRR sensor collects multispectral data
and has a 2400-km swath width and l-km spatial
resolution. Therefore, it can be used to evaluate
vegetation and landforms throughout an ecoregion.
1993 Resource Planning Act Forest Type
Group Map
Two forest cover maps for the conterminous United
States have been derived from AVHRR data (Zhu
and Evans, 1994). A forest density map was created by modeling the percent forest cover per
square kilometer (Figure 10.3) (Zhu, 1994). A second map of forest-type groups depicting the spatial
distribution of 22 forest-type groups was also produced for this project. These maps were made as
part of the 1993 Resource Planning Act (RPA) assessment update (Powell et al., 1993). Forest Inventory and Monitoring (FIM) data from different
Forest Service regions were linked to the images
to identify regional vegetation patterns. For example, the FIM data showed a transition of pine to upland hardwoods in Alabama over the past two surveys. The forest-type group map depicted a related
transitional zone between the loblolly-shortleaf
type and the oak-hickory and oak-pine types. For
more information, see the project's Web site
(http://srsfia.usfs.msstate.edu/rpalrpa93.htm).
Subregion
Next in the hierarchy are subregions, which are further divided into sections and subsections. Regional
environmental factors, such as geomorphic processes,
topography, and climate, influence the determination
of subregions (Avers et aI., 1993). Projects conducted over a number of National Forests or across
a state are subregional. Sensors with midrange spatial resolution, such as Landsat TM, are appropriate for this level. Additionally, some small-scale,
Remote Sensing Applied to Ecosystem Management
0%
50%
100%
FIGURE 10.3. Percent forest cover area per square kilometer for the conterminous United States.
enced by latitude, continental position, and elevation. Vegetation macrofeatures determine where divisions are broken into provinces. A VHRR data are
a good choice for assessing ecosystems at these levels. The A VHRR sensor collects multispectral data
and has a 2400-km swath width and l-km spatial
resolution. Therefore, it can be used to evaluate
vegetation and landforms throughout an ecoregion.
1993 Resource Planning Act Forest Type
Group Map
Two forest cover maps for the conterminous United
States have been derived from AVHRR data (Zhu
and Evans, 1994). A forest density map was created by modeling the percent forest cover per
square kilometer (Figure 10.3) (Zhu, 1994). A second map of forest-type groups depicting the spatial
distribution of 22 forest-type groups was also produced for this project. These maps were made as
part of the 1993 Resource Planning Act (RPA) assessment update (Powell et al., 1993). Forest Inventory and Monitoring (FIM) data from different
Forest Service regions were linked to the images
to identify regional vegetation patterns. For example, the FIM data showed a transition of pine to upland hardwoods in Alabama over the past two surveys. The forest-type group map depicted a related
transitional zone between the loblolly-shortleaf
type and the oak-hickory and oak-pine types. For
more information, see the project's Web site
(http://srsfia.usfs.msstate.edu/rpalrpa93.htm).
Subregion
Next in the hierarchy are subregions, which are further divided into sections and subsections. Regional
environmental factors, such as geomorphic processes,
topography, and climate, influence the determination
of subregions (Avers et aI., 1993). Projects conducted over a number of National Forests or across
a state are subregional. Sensors with midrange spatial resolution, such as Landsat TM, are appropriate for this level. Additionally, some small-scale,