Growth history of a Neotropical tree inferred from the spacing of leaf scars

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Abstract
The Neotropical tree,Pourouma aspera(Cecropiaceae), supports large lobed leaves on an erect stem which seldom branches below a height of 5 m. The prominent leaf scars are visible on trunks of mature trees and the distance between scars is highly correlated with the height growth rate when the leaves were produced. Relationships between height growth rate, internode length and light environment were determined from markedP. asperasaplings in a tropical wet lowland forest and used to infer the past growth histories of larger saplings and trees. Inferred growth rates were quite variable, both within and between individuals. Estimated passage times to grow from 0.7 to 2.2 m tall ranged from 0.6–23 y, with a mean of 4.4 y (N = 61). The study illustrates the importance of examining the distribution of growth rate over the length of the stem in addition to the more usual distribution of numbers of individuals per growth rate class. Species such asPourouma, which respond strongly to light, complete much of their total juvenile growth during intervals of high light, even though most saplings are growing slowly in shade at any given time.