Julia Glenday

A Preliminary Assessment of Carbon Storage and the Potential for Forestry Based Carbon Offset Projects in the Kakamega National Forest, Kenya

Environmental Science Thesis, May 2004

Abstract

            Forestry based carbon offset projects have the potential to act as both a climate change mitigation tool and a means of fostering sustainable forest preservation. While modeling has provided positive assessments of the potential for African tropical forests to sequester large amounts of carbon, the lack of localized field studies has limited the feasibility of initiating biotic carbon emissions offset projects in many of the continents threatened forests. This study provides an analysis of carbon storage and the potential to increase carbon stocks in the Kakamega National Forest of western Kenya, a threatened African rainforest fragment. Such an assessment is required by Kenya’s commitments under the United Nations Framework Convention on Climate Change and as a baseline for participation in the Clean Development Mechanism of the Kyoto Protocol to the convention.

Carbon density values for indigenous forest and plantations were estimated based on data collected in ninety five randomized 20x20m plots throughout the Kakamega National Forest from June to August of 2003. Tree biomass was estimated from diameter at breast height (dbh) measurements and allometric equations, while litter and herbaceous vegetation biomass was quantified using destructive sampling. Soils were sampled using both combustion and spectroscopy techniques. Land cover maps for 1975, 1986, and 2000 from Kenya’s Department of Remote Sensing and Resource Surveys (DRSRS), were used to estimate both current carbon storage in the forest and the influence of land use change over the past 25 years on forest carbon stocks.

The average carbon storage density in indigenous forest is 330 ± 65 Mg C/ha (95% confidence interval), which is greater than that of the average found in the forest’s hardwood plantations (280 ± 77 Mg C/ha) and significantly greater that that of softwood plantations (250 ± 77 Mg C/ha). Deforestation between 1975 and 1986 and limited reforestation from 1986 to 2000 have resulted in a net loss of 0.6 ± 0.1 Tg C. The distribution of carbon densities within the indigenous forest and variation between plantation types suggests that there are management practices that could increase Kakamega’s carbon stock back to speculated 1975 levels if not higher. Even given current low carbon prices, a 0.6 Tg C increase in carbon stock could represent a $3 million value, a figure that dwarfs the operational budgets of the forest’s management bodies and could begin to address the income deficit in the region.