Rates of Dry-matter Production in Some Tropical Forest-tree Seedlings

An analysis of growth in full daylight of four tropical forest-treeseedlings and Helianthus was made with the view of ascertainingwhether woody plants in the tropics have a lower net assimilationrate than herbaceous plants as has been demonstrated in otherenvironments. Significant differences in net assimilation ratewere found between Helianthus and three of the woody speciestested: Chlorophora excelsa, Musanga cecropioides, and Terminaliaivorensis; the fourth woody plant, Ceiba pentandra, had an unusuallyhigh net assimilation rate which, in one experiment, did notdiffer significantly from the value found for Helianthus. The data are discussed in relation to the general problems ofcomparative growth-rates of herbaceous and woody plants andof factors contributing to differences in forest productivitybetween climates.