J. J. Battles | USGS Science

USGS2007

The relationship between tree growth patterns and likelihood of mortality: A study of two tree species in the Sierra Nevada

We examined mortality of Abies concolor (Gord. & Glend.) Lindl. (white fir) and Pinus lambertiana Dougl. (sugar pine) by developing logistic models using three growth indices obtained from tree rings: average growth, growth trend, and count of abrupt growth declines. For P. lambertiana , models with average growth, growth trend, and count of abrupt declines improved overall prediction (78.6% dead trees correctly classified, 83.7% live trees correctly classified) compared with a model with average recent growth alone (69.6% dead trees correctly classified, 67.3% live trees correctly classified). For A. concolor , counts of abrupt declines and longer time intervals improved overall classification (trees with DBH ≥20 cm: 78.9% dead trees correctly classified and 76.7% live trees correctly classified vs. 64.9% dead trees correctly classified and 77.9% live trees correctly classified; trees with DBH <20 cm: 71.6% dead trees correctly classified and 71.0% live trees correctly classified vs. 67.2% dead trees correctly classified and 66.7% live trees correctly classified). In general, count of abrupt declines improved live-tree classification. External validation of A. concolor models showed that they functioned well at stands not used in model development, and the development of size-specific models demonstrated important differences in mortality risk between understory and canopy trees. Population-level mortality-risk models were developed for A. concolor and generated realistic mortality rates at two sites. Our results support the contention that a more comprehensive use of the growth record yields a more robust assessment of mortality risk.

California↗

USGS1992

Regional evaluations of acid deposition effects on forests: Eastern spruce-fir

Having reviewed the results of the Integrated Forest Study (IFS) project, we now try to place the results in a larger perspective by very briefly summarizing acid deposition effects and their potential role in forest health in the several forest types represented in the IFS project. This chapter gives brief overviews of the situation in eastern spruce-fir, eastern hardwood, and southern pine forests in North America; and a very brief overview of air pollution in arid forest ecosystems in Europe (with special emphasis on the situation in Norway where the single European IFS site was located). What follows in this chapter is by no means intended to be a comprehensive review of forest health and atmospheric deposition; such an analysis would require a volume of this size for each forest type and is well beyond the scope of this chapter. A comprehensive analysis of forest health and the role of atmospheric deposition has been published for Norway spruce in Europe (Schulze et al. 1989), and one is in preparation for red spruce (Eagar and Adams, in press); the reader is referred to those volumes for a far more detailed discussion than is possible here. The intent of this chapter is merely to highlight those aspects of forest health and atmospheric deposition that have bearing on, or that can be illuminated by, the IFS results.

Book chapter↗