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Database from forest inventory of the different states and provinces of western North America

Citation

Messaoud, Yassine (2020), Database from forest inventory of the different states and provinces of western North America, Dryad, Dataset, https://doi.org/10.5061/dryad.w9ghx3fms

Abstract

The climate variables effect on tree growth in boreal and temperate forests has received increased interest in the global context of climate change. However, most studies are often limited to local or regional scales and involved a few tree species. Here, sixteen tree species across western North America were used to investigate tree response to climate change at the species range scale.

Forest inventory databases from 36,944 stands established between1600 and 1968 throughout western Canada and USA were summarized. Height growth (total height at breast-height age of 50 years) of healthy dominant and co-dominant trees were related to climate variables (annual and summer temperature, annual and summer Palmer Drought Severity Index) and tree establishment date (ED) using general linear model. Climate-induced height growth patterns were then tested to determine possible links to spatial environment (soil conditions and geographic locations), species range (coastal, interior, and both ranges) and species traits (shade tolerance and leaf form).

Climate variables had a positive effect on height growth for most of the study species, except for a negative relationship of Alaska yellow-cedar height growth to ED. All explaining variables and the interactions explained 57.2% of the total species height growth variance. Although tree height growth response was species-specific, increased height growth during the 20th century was more pronounced for coastal ranged species, high shade tolerant species, and broadleaf species. Furthermore, height growth increase occurred mostly on rich soil, at the northernmost species range, and, unexpectedly, at lower elevations. A decline in height growth for some species further north and higher in elevation possibly related to increased precipitation and cloudiness, drought conditions in interior areas, or to the peculiarity of western North America topography. These results highlight the spatial and temporal complexity of the growth response patterns at the species range to recent global climate change.