Reproductive Traits of Trees in OFR

Abstract

When plants start to reproduce (when they reach a certain size or the age of onset of flowering and fruiting), how often and how many of the plants produce offspring during their lifetime (frequency of reproduction) and how many offspring are produced in a year (magnitude of reproduction) are important factors of plant demography, because these factors determine the lifetime fecundity of the plants. Concerning the critical size of reproduction of plants, many studies have been conducted for herbaceous perennials and monocarpic species. There are intraspecific variations in the size of reproductive individuals, and it has been pointed out that not only the size but also the growth rate of individual plants relate to the timing of their reproduction (Reekie et al. 1997; Wesselingh et al. 1997). Several models of the critical size of reproduction that take into account growth rate (Kohyama 1982; Nakashizuka et al. 1997) show that both size and growth rate affect the resource. Differences in reproductive traits are important factors contributing to the ability of tree species to coexist in a forest (Kohyama 1993; Thomas 1996). However, the long life span, large individual size, and diverse environmental conditions of tree habitats make it difficult to analyze and model the reproductive traits of tree species in a forest community. It is important to construct a simple model of the critical conditions of reproduction of tree species based on empirical data to understand tree life histories and coexistence mechanisms in a forest community.