Reviews

ASHTON, P.S., Crown characteristics of tropical trees. In Tomlinson & Zimmermann (ed.), Tropical Trees as Living Systems (1978) p. 591-615, 8 fig. An important subject in relation to bioproduction. Approaches are through Leaf Area Index (the area of leaf surface above a unit area of ground) and Leaf Area Density (ditto per volume of space). Field work was done in Malaya by students; the simple methods are described. Macaranga gigantea is compared with Musanga cecropioides; other pioneer species are quite different, however. Two profile diagrams of secondary forest are given. Crowns are modified in competition, as reflected in LAI and LAD. Plagiotropic branching allows trees to broaden quickly. Light- or shadepreference is not clearly correlated to architectural model. Givnish & Vermey’s prediction of variation in leaf shape, size, and inclination in lianas as a result of transpirational costs against photosynthetic gains, is discussed and clarified. Dipterocarps may change their model in maturity. — M.J.