Aboveground Biomass and Nutrients in Young Plantations of Indigenous Trees on Infertile Soils in Costa Rica

Abstract

Aboveground-tree biomass and nutrient content (nitrogen, phosphorus, calcium, magnesium and potassium) were measured in 4-year-old stands of four indigenous tree species: Stryphnodendron microstachyum Poepp. et Endl. (ex S. excelsum Harms), Vochysia guatemalensis Donn. Smith (ex V. hondurensis Sprague), Vochysia ferruginea Mart and Hyeronima alchorneoides (0), growing on infertile soils in an experimental plantation in the Atlantic humid lowlands of Costa Rica. Biomass and nutrient content among the species, and among aboveground tree parts, forest-floor litter and understory vegetation were compared, as key factors that can be manipulated with different effects on site nutrient conservation. Biomass and stemwood annual increments of the four species were similar to those reported for other tropical tree plantations in the humid tropics. S. microstachyum had the highest accumulation of N in stem, branch and total aboveground tree biomass. V. guatemalensis had the highest accumulation of Ca and Mg in the biomass, while H. alchorneoides had the highest stem K and P. In spite of heir relatively lower N tissue collcentrations. V. ferruginea and H. alchorneoides showed a high potential for N recycling due to its more even distribution in stems, branches and leaves. Nument accumulation by the understory in S. microstachywn and H. alchorneoides plots was 0.8-7.746 of aboveground see biomass numents. The forest floor litter repsented a major compartment for nutrient accumulation and recycling under the four species, especially for N, Ca, Mg and P.