Potential hazard rating system for fir stands infested with budworm using cambial electrical resistance

Abstract
Cambial electrical resistance (CER) of more than 10 000 trees, predominantly balsam fir (Abiesbalsamea) and red spruce (Picearubens) was measured in 90 stands in northern Maine, New Hampshire, and Vermont, U.S.A. CER index values (mean CER, kiloohms per stand) ranged from 9 to 13 for fir in nonoutbreak situations, and 9 to 18 in outbreak situations with moderate to heavy budworm infestation, whereas values for red spruce remained essentially constant at 7 to 13 in both situations. Balsam fir trees in stands with an index value of 9 grew almost three times faster (diameter growth) than in stands with an index value of 13. An increase of index values from 13 to 18 in outbreak situations indicated no further reduction in growth, but may indicate impending mortality of trees with lower vitality. Such index values may be useful in developing a hazard rating system for fir stands infected with spruce budworm.

This publication has 0 references indexed in Scilit: