Shade tree diversity and aboveground carbon stocks in Theobroma cacao agroforestry systems: implications for REDD+implementation in a West African cacao landscape.

Winston Asante,Emmanuel Acheampong,Paul Bosu,Evans Dawoe

doi:10.1186/s13021-016-0061-x

Abstract

BackgroundThe promotion of cacao agroforestry is one of the ways of diversifying farmer income and creating incentives through their inclusion in REDD+ interventions. We estimated the aboveground carbon stocks in cacao and shade trees, determined the floristic diversity of shade trees and explored the possibility of implementing REDD+ interventions in cacao landscapes. Using replicated multi-site transect approach, data were collected from nine 1-ha plots established on 5 km long transects in ten cacao growing districts in Ghana West Africa. Biomass of cacao and shade trees was determined using allometric equations.ResultsOne thousand four hundred and one (1401) shade trees comprising 109 species from 33 families were recorded. Total number of species ranged from 34 to 49. Newbouldia laevis (Bignoniacea) was the most frequently occurring specie and constituted 43.2 % of all shade trees. The most predominant families were Sterculiaceae and Moraceae (10 species each), followed by Meliaceae and Mimosaceae (8 species each) and Caesalpiniacaea (6 species). Shannon diversity indices (H’, Hmax and J’) and species richness were low compared to other similar studies. Shade tree densities ranged from 16.2 ± 3.0 to 22.8 ± 1.7 stems ha−1 and differed significantly between sites. Carbon stocks of shade trees differed between sites but were similar in cacao trees. The average C stock in cacao trees was 7.45 ± 0.41 Mg C ha−1 compared with 8.32 ± 1.15 Mg C ha−1 in the shade trees.ConclusionsCacao landscapes in Ghana have the potential of contributing to forest carbon stocks enhancement by increasing the stocking density of shade trees to recommended levels.Electronic supplementary materialThe online version of this article (doi:10.1186/s13021-016-0061-x) contains supplementary material, which is available to authorized users.

Highlights

The promotion of cacao agroforestry is one of the ways of diversifying farmer income and creating incentives through their inclusion in REDD+ interventions
Possibility of implementing REDD+ interventions in studied cacao landscapes Results of this study reveal that, contrary to existing assumptions, unshaded cacao systems meet the height requirements to qualify as forest per Ghana’s forest definition for climate change mitigation projects
The extent to which cacao landscapes would contribute to the realization of REDD+ objectives hinges very much on Ghana’s definition of forest

Summary

Introduction

The promotion of cacao agroforestry is one of the ways of diversifying farmer income and creating incentives through their inclusion in REDD+ interventions. There is a general belief that cultivation of cacao, as traditionally practiced in Africa, has the potential to restore carbon stocks to levels comparable to that in the native forest which they replaced. It is intuitive that carbon stocks in cacao farms with dense tree canopy cover will be much similar to that in the original native forest than in farms with lower or no canopy shade. Several studies have revealed that a larger proportion of the carbon stocks in most cacao agroforests are contributed by the shade trees [5,6,7,8]. The question is whether carbon stocks in these emerging cacao plantations will be within reasonable proportion of the original native forests they have replaced. Understanding carbon accumulation dynamics in cacao agro-ecosystems is important to the long-term management of cacao farms that inure to climate change mitigation and the associated socioeconomic effects

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