Predictive models were developed for Cordia alliodora branch and Theobroma cacao branch or leaf biomass based on branch basal areas (r 2 /> 0.79) but the model of C. alliodora leaf biomass, although significant, was of very low accuracy (r 2 = 0.09) due to annual leaf fall. At age 10 years, shade tree stem biomass accounted for 80% of the total above-ground biomass of either tree. However, between the ages of 6 and 10 years, the biomass increment of T. cacao branches (3-4 t.ha ~.a -t) was similar to that of the shade tree stems. During the same period, the net primary productivity was 35 and 28 t.ha=t.a -~, for the Erythrina poeppigiana and C. alliodora systems, respectively.Cocoa production under either of the shade trees C. alliodora or E. poeppigiana was 1000 kg.ha-t.a -t (oven-dry; ages 6-10 yr). During the same period, C. alliodora timber production was 9 m3.ha -~ .a -~ whilst the leguminous shade tree E. poeppigiana does not produce timber. Litterfall over the same 5 years, including crop and/or shade tree pruning residues, averages 11 and 23 t.ha-~.a -~, respectively. The main difference was due to E. poeppigiana pruning residues (10 t.ha-l.a-I).Soil organic material reserves (0-45 cm) increased over 10 years from 198 to 240 t.ha ~ in the E. poeppigiana plots and from 168-184t.ha -~ in the C. alliodora plots. These values, together with the productivity indices presented, provide evidence that the systems are sustainable.For economic reasons, the use of C. alliodora is recommended under the experimental conditions. However, on less fertile soils without fertilization, the greater biomass and hence nutrient return to the soil surface under E. poeppigiana, might make this the preferable shade tree. 230

Land conversion in the tropics from primary forest to agricultural land has altered soil hydrologic processes. Woody vegetation is known to increase infiltration rates and saturated hydraulic conductivity (KS) in primary forests compared with agricultural land, but it is less clear if this relationship holds for a gradient of woody vegetation. In addition, the mechanisms for the effect of woody vegetation on KS have yet to be fully examined. To quantify the effect of woody vegetation structure on vadose zone hydrology, we estimated KS in 15 plots across a dry tropical riparian vegetation gradient in Nicaragua, taking into account covariates such as soil properties and livestock impact. Using single linear regression, we found that leaf area index (LAI) had the greatest correlation coefficient of 0.331 to KS, followed by hoofprint density (0.291) and clay content (0.291). Furthermore, the relationship between LAI and KS was greater for finer soils than for coarser soils. We found that a forest soil had eight times more preferential flow paths than a pasture soil, and most of these were root‐initiated flow paths, suggesting a possible mechanism for the positive correlation between LAI and KS. We show that the KS predictions with a pedotransfer function could be improved by incorporating LAI. Our findings support the importance of preserving woody vegetation in key areas on the landscape to maintain hydrologic functions of tropical soils and ecosystems.

Autores. Editado por la AEET. [Ecosistemas no se hace responsable del uso indebido de material sujeto a derecho de autor] Influencia del gradiente altitudinal sobre la estimación del carbono almacenado en biomasa aérea viva y en suelos del "Bosque y vegetación protector El Artesan -EcuadorianHands". Joa, Jipijapa