Dendroecological Analysis of Relationships between Growth of Eastern White Pine ('Pinus strobus L.') and Regional Air Pollution in the Eastern United States, Using the Forast Database

摘要

Eastern white pine (Pinus strobus L.) has been described in the scientific literature as particularly sensitive to air pollution based on foliar injury symptoms, decreased growth, and increased mortality. Wide genotypic variability in tolerance of eastern white pine to air pollution has also been documented. Increment cores from 360 white pine were collected from a total of 24 sites in Tennessee, Virginia, Pennsylvania, Connecticut, Vermont, New Hampshire, and Maine as part of the FORAST (Forest Response to Anthropogenic Stress) project. The study analyzed the FORAST tree growth, air pollution, climate, and competition databases to determine if unexplained alterations in recent growth of white pine occur in a spatial/temporal pattern suggestive of air pollution effects. There is little evidence of widespread growth decline in this sample of white pine. Consistent with reports in the literature, regional mean BAI curves indicate growth has been constant or increasing from 1930 to 1980 for all regions sampled. However, a small proportion (9%) of the sample population exhibits post-1960 alterations in growth trends indicative of tree decline. Regional differences in tree age/size and recent stand dynamics obscured spatial patterns between incidence of tree decline and air pollution. Dendroclimatic analyses indicate white pine growth-climate relationships may have been altered at sites with high ozone exposure. Beginning in the 1950's, growth-climate correlations decrease markedly at high ozone exposure sites. However, the FORAST database has limitations that preclude a rigorous analysis of this potential ozone-climate interaction.