Age-Size Relationships and Growth Behavior of the Palm Welfia georgii

Height growth rates and age-height relationships are reported for the abundant arborescent geonomoid palm Welfia georgii growing in tropical wet forest at La Selva, Costa Rica. Height increments over the 10-yr period range from 0.3 to 9.9 m, with a modal value of 2-3 m/10 yr. The data were analyzed using growth simulation, a stochastic bootstrapping technique that projects growth trajectories from periodic increment data. The number of years needed to attain the maximum height of 20 m from an initial height of 2.3 m ranges from 31 at the fastest growth rate to 80 at the slowest. The median value is 68 yr. Welfia palms appear to grow more or less continuously once they have reached 2.3 m. The wide variation in canopy conditions under which the present sample of surviving Welfia is growing indicates that the species tolerates a considerable range of light regimes. PALMS (LIKE OTHER TREES) in nonseasonal tropical environments seldom leave interpretable physical evidence of their growth history and age. Repeated measurements of tagged individuals over long periods are therefore necessary. Because palms lack a vascular cambium and do not show ordinary secondary stem growth, other variables must be measured to assess growth rates and infer age (see Piniero et al. 1977, Sarukhan et al. 1984). We report height growth behavior over a 10-yr period of the arborescent geonomoid palm Welfia georgii Wendl. (referred to hereafter as Welfia) and apply a stochastic growth simulation procedure (Lieberman & Lieberman 1985) that uses height increment data to project age-height relationships and longevity values for the species.