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).