ABSTRACT
A BRIEF examination of the distribution of all the main types of forest in middle and high latitudes reveals a pattern which is most confusing in its complexity. Although in some places there seems to be a close correlation between the distribution of a certain dominant life-form and a particular type of climate, in analogous climatic areas quite a different type of vegetation occurs. The relationship between climate and life-form is obviously far from absolute. Indeed, anomalies are so numerous that it is pointless, if not positively misleading, to make generalisations about such relationships. In the main an unsystematic patchwork of coniferous, broad-leaved evergreen, broad-leaved deciduous and mixed forests is revealed. Conifers are dominant on the edge of the tundra in northern Europe and on the fringes of the Sahara in Morocco. Mixed evergreen forests extend to the extreme tip of Tierra del Fuego in Chile, broad-leaved deciduous trees occupy analogous areas in Europe while an almost pure coniferous formation is found in western North America. Only the boreal forest, composed predominantly of evergreen conifers, seems to dominate throughout a whole climatic region with any degree of continuity and, even here, there are significant anomalous features. Some broad-leaved deciduous species are of frequent occurrence within the boreal forest; they even appear to be dominant in large areas such as the Kamchatka Peninsula (Map 2). More important still, where the boreal forest reaches its northernmost limit at about 72° 50' N. in eastern Siberia, it is dominated not by evergreen conifers but by the deciduous Dahurian larch (Larix dahurica). It is quite clear from these selected examples that all the attempts that have been made to explain the distribution of forest types in simple climatic terms are premature and, ultimately, probably completely fruitless.
