Forest Structure and Health Trends in the Southern Appalachian Montane Spruce-fir and Northern Hardwood Ecosystems of the Black Mountains, North Carolina PDF Download

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Book Description
Spruce-fir forests of the Southern Appalachians are ice age relics currently existing now in isolated montane islands at elevations above 1400 m. Decline in the spruce-fir ecosystem throughout the region was shown following extensive surveys in high elevation red spruce (Picea rubens Sarg.) and Fraser fir (Abies fraseri (Pursh) Poir.) forests conducted during the 1980?s. Following an observed decline in red spruce crown condition at lower elevations (1500 m) in the Black Mountains of North Carolina during the summer of 2001, it was deemed necessary to conduct a new investigation to characterize trends in forest health in the spruce-fir and adjacent northern hardwood forests. Beginning in 2002, we undertook a new study in order to gain further information relating to the observed decline by resurveying 28 permanent spruce-fir forest plots installed in 1985 at 1525, 1675, 1830, and 1980 m in the Black Mountains. Simultaneously, we established a new system of 40 permanent plots to survey the northern hardwood forests in 9 areas throughout the Black Mountains between 1220 and 1525 m. Following previous protocols in the spruce-fir forest, and using a similar rubric in the northern hardwood forests, we measured live and dead basal area, live and dead stem density, and assessed tree crown conditions for all overstory species. Insect and disease occurrences were also recorded when found with special attention given to balsam woolly adelgid (Adelges piceae Ratz.) on Fraser fir, hemlock woolly adelgid (Adelges tsugae Annand) on hemlock, beech scale insect (Cryptococcus fagisuga Lindinger) and cankers caused by Nectria coccinea var. faginata (Lohman, Watson and Ayers) on beech, and low crown vigor or defoliation in oaks. Individual plot assessments in the spruce-fir zone revealed a wide range of response over the 17-year interim and while few results were statistically significant, several profound trends were evident. Results show a large increase in live basal area at 1980 m.