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This paper presents data on and discusses the degree of postglacial stability of the northern Canadian tree limit. Holocene climatic changes have been both directional and synchronous for this region, though deteriorations/ameliorations either (1) lagged from west to east, (2) were buffered by local geographic factors, or (3) were not registered in the fossil record owing to the inherent persistence of the vegetation at some sites. The present northern tree limit in eastern Canada is in equilibrium with the prevailing climate, with the tree populations successfully regenerating both sexually and vegetatively. These tree stands are still occupying their maximum Hypsithermal positions. In contrast, the tree limit, tree line, and intervening forest-tundra ecotone in central and western Canada are out of equilibrium with today's climate. These populations are not sexually regenerative and apparently became established during warmer climates where the tree line was north of its present position. As such, they are susceptible to destruction by further climatic deterioration or anthropogenic disruption. [ABSTRACT FROM AUTHOR]

This paper provides an analysis of the soils and terroirs of the vineyards of the Napa Valley, CA. Following an overview of the geological history of the state and its effect on soil formation, a summary of the physical environment of the Napa Valley is given. This is followed by a survey of the different viticultural environments found in the Napa Valley, divided into four geographical regions. The paper argues that the natural physical environment exerts important controls on viticulture and that subtle soil differences can be reflected in the wines of the region. [ABSTRACT FROM AUTHOR]