Timber growth, cacao yields, and financial revenues in a long-term experiment of cacao agroforestry systems in northern Honduras

Abstract

We assessed 36 cacao plots made up of 15–35 useful timber shade trees with varying spacing 6 × 9, 9 × 9, 8 × 10, and 10 × 12m. Initially, each plot consisted of three shade components plus cacao. Plantain (Musa x paradisiaca) and madreado (Gliricidia sepium) were used as temporary shade and timber species, were selected as permanent shade. Dasometric data were retrieved to assess growth rates of timber species and cacao yield per plant were recorded to explore the efects of shade cover yield performance and the incidence of main diseases. Specifically, we: a) calculated growth rates and build curves for diameter (DBH), total height (Ht), and commercial volume (Vc) and compared the growing performance with ANOVA and DGC tests; b) run a correlation analysis between shade cover, timber basal area, cocoa yields, and the incidence of monilia and black pod. Statistical diferences were found in terms of growth rates among timber species evaluated. Mean annual growth rates were 2.25cm in DBH, 1m in Ht, and the standing commercial timber gained was 4.2 m3/ha/year. Cocoa yields ranged between 950 and 1,365 kg/ha/year and were negatively afected by both increased tree cover and timber basal area. Cacao yields were reduced up to 25% when tree cover and tree basal areas were over 40% and 10 m2, respectively. Regardless of timber tree species, no significant efect of tree cover was found on the incidence of cacao diseases. After 22 years, total revenues were determined by the proportion of incomes provided by each component of the agroforestry systems assessed. Five out of 12 timber-based cacao plantations accumulated more than U$95,000 of combined revenues, equivalent to incomes of US$3775 ha−1 year−1. Timber-based cacao plantations are a promising alternative for farm diversification in northern Honduras.