The latitude-elevation relationship for spruce-fir forest and treeline along the Appalachian mountain chain

Abstract

Spruce-fir forests extend along the Appalachian Mountains of eastern North America from 35 ° to 49 ° N.This montane vegetation differs from boreal spruce-In" forest in that it is dominated by Picea rubens, has a higher vascular species richness, has wind, rather than fire, dominated dynamics, and has a mean annual temperature above 2 ° C. Using field reconnaissance, remote sensing, and literature review we described and modeled the latitude-elevation relationship for Appalachian spruce-fir. The elevation of the sprucefir/deciduous forest ecotone decreases from 1,680 m at 35 ° N to 150 m at 49 ° N, while the elevation of treeline (spruce-fir/tundra ecotone) decreases from 1,480 m at 44 ° N to 550 m at 55 ° N. Linear regressions gave latitude-elevation relationships of -100 m/1 ° Latitude for the spruce-fir/deciduous forest ecotone and -8 3 m/1 ° Latitude for treeline. These values compare to literature reports of -5 4 to -230 m/1 ° Latitude and are most similar to values reported from eastern Asia. The latitude-elevation relationship for mean July temperature ( -94 to -121 m/1 ° Latitude) was more similar to the slopes of these ecotones than is the slope for mean annual temperature ( -170 to -220 m/1 ° Latitude). The spruce-fir/deciduous forest ecotone was correlated with a mean July temperature of approximately 17 ° C. Treeline was correlated with a mean July temperature of approximately 13 °C.

A rapid upward shift of a forest ecotone during 40 years of warming in the Green Mountains of Vermont

“…1). The location of the NBE is expected to be strongly related to local climate across the northeastern United States (24,25). We examined changes in forest composition in vegetation plots at 11 elevations spaced at 61 m (200 ft) vertical increments from 550 to 1,160 m a.s.l.…”

“…In northeastern North America, montane forests exhibit distinct elevational zonation, with species' elevational ranges analogous to latitudinal range limits (22)(23)(24). The transition from northern hardwoods at lower elevations to boreal forest at upper elevations occurs across a narrow elevational zone [northern hardwood-boreal ecotone (NBE)], where there is a near-complete turnover from northern hardwoods [99.2% of the current basal area below 730 m above sea level (a.s.l.)]…”

Contribution of mass elevation effect to the altitudinal distribution of global treelines

“…Treeline elevation has been often associated with latitude or latitude-related temperature, and a number of treeline elevation-latitude models have been developed to determine treeline elevation at regional and global scales (Malyshev 1993;Cogbill et al 1991;Fang 1995;Körner 1998). However, regional models are only effective regionally and cannot be applied to global scale.…”

Vegetation databases provide a close-up on altitudinal tree species distribution in the Bavarian Alps

“…However, due to the coarse resolution of distribution and climate data, recent SDMs have devoted more attention to the northern margin (Sykes et al 1996) than to temperate mountains with their fine-grained altitudinal gradients ). In order to yield reliable scenarios, SDMs must reflect the physiological constraints at both types of cold margin (Cogbill & White 1991 In Central European mountains, the tree form of Fagus sylvatica reaches a conspicuous limit at 4 °C mean annual temperature, which prevails far beyond the northern distribution limit, e.g. in Southern Finland.…”