Symposium on Remote Sensing for Resources Development and Environmental Management / Enschede / August 1986
Inventory of decline and mortality in spruce-fir forests
of the eastern U.S. with CIR photos
W.M.Ciesla, C.W.Dull, L.R.McCreery & M.E.Mielke
USDA Forest Service, Forest Pest Management, USA
ABSTRACT: An accelerated decline and mortality of several commercially important trees, including red spruce,
Picea rubens, has recently been reported in the eastern United States. The causal agents responsible for this
syndrome are not yet fully known. This has led to a concern that some form of anthropogenic pollution may be
involved.
Beginning in 1984, a series of special inventories were conducted by the Forest Pest Management
organization of the USDA Forest Service to quantify the status of red spruce decline and mortality throughout
its natural range. Color infrared aerial photography was used as an integral stage of these surveys.
Photographic parameters and survey design approaches are described, and examples of survey results are
presented. Resultant data are being stored in geographic information systems to facilitate integration with
other resource information and research data.
Survey designs currently used in the United States are compared to European approaches for assessment of
similar types of damage.
1 INTRODUCTION
During the early 1980's the occurrence of forest
decline and mortality of an unexplained origin was
reported for several tree species in the eastern
United States. One of these was red spruce, Picea
rubens, a major component of the boreal or northern
coniferous forest.
The specific causes of the decline of red spruce
are not yet clearly understood. However, several
workers have discussed the potential role of
anthropogenic pollutants as inciting factors
(Siccama et al. 1982; Johnson and Siccama 1983).
Beginning in 1984, a series of special inventories
was initiated by the Forest Pest Management
organization of the USDA, Forest Service to estimate
levels of decline and mortality of red spruce and
its major associated species. Color-IR aerial
photography was an integral part of these
inventories.
2 DISTRIBUTION AND ECOLOGY OF RED SPRUCE
Red spruce is a tree native to the eastern United
States and adjoining Canada, and is a major
component of the northern coniferous forest. The
tree is found from Nova Scotia south to North
Carolina and Tennessee (Fig. 1). Throughout a large
portion of its natural range, red spruce is most
abundant at high elevations. In the states of New
Hampshire and Vermont, the lower elevational limit
for red spruce is ca. 600 m. In the Adirondack
Mountains of New York, the tree usually occurs at
elevations above 750 m. In the central Appalachian
Mountains, red spruce does not occur below 900 m.
and in southwestern Virginia, North Carolina, and
Tennessee, the southern limits of its natural range,
the lower elevational limit of red spruce is ca.
1400 m.
The principle species associated with red spruce
in the northern part of its range is balsam fir,
Abies balsamea. Other associated species include
Figure 1 - Distribution of Picea rubens in North
America (Little 1971).
