PARENT SESSION
Contributed Oral Session 130: Forest Infestations and Mortality
Thursday, August 11, 1:30 PM - 5:00 PM, Meeting Room 514 A, Level 5, Palais des congrès de Montréal

Characterization of mortality rate in tropical rainforest plantation trees.

Hanson, D. Eric¹, ¹ American Samoa Community College, Pago Pago, AS, USA

ABSTRACT- A old-field reforestation study was initiated in 1998 using eight species of commercially important lowland rainforest trees on the island of Tutuila, American Samoa. The study was a CRD with four replications and 36 trees per plot. Although all 36 trees were measured for height and DBH, only the center 16 were used in the analysis. ANOVA was performed on the plot means for survival and yield data collected 2, 4, 5, and 6 years after planting using these center trees. The species fell into two groups based on survival from planting to Year 2: Those with high initial mortality and those with low initial mortality. This result is attributed to the effect of height growth rate, which is antiipated to be inversly proportional to initial mortality. In subsequent years, a second grouping was suggested: Species with overall low mortality rates, those with steady mortality rates, and those with precipitous mortality. This grouping is hypothesized to related to the degree of shade tolerance in the various species, with a direct relationship between it and increased mortality rate. Althought the ability to detect differences among species in the experimental design was low, patterns emerged when taking into account overtopping canopy cover as a covariate. An experiment has been initiated to test the hypotheses of growth rate affecting initial survival and variable shade tolerance among the species. A factorial arrangement of vegetation control treatments and shading levels is used in this latter study and will be briefly discussed.

Key words: shade tolerance, competing vegetation, American Samoa, reforestation