Carbon storage and forest fire influences in tropical rainforests

Abstract

Deforestation and degradation account for nearly 20 percent of global greenhouse gas emissions today – playing a key role in the complex system of climate change. Most deforestation is undertaken in developing countries, resulting in loss of biodiversity and livelihoods for millions of people and animals. With an increasing recognition of this problem the term REDD (Reducing Emissions from Deforestation and Degradation) emerged during the last years. The basic idea behind a REDD regime is that developing countries receive financial incentives for preventing further deforestation to protect the worldwide climate. Whereas afforestation and reforestation projects were included in the initial Kyoto Protocol, REDD was only eligible for the voluntary carbon market, where criteria and best guidance for these project types were developed and where some avoided deforestation projects were implemented. One of these projects was the “Avoided Deforestation Project in the Sierra del Lacandón National Park”, placed in the Maya Biosphere Reserve in Northern Guatemala. The company Carbon Decisions International was selected to create a deforestation model for the reference region of Petén. Within this context the objective of this thesis was to analyze the effects of forest fires on carbon stocks in the study area and to analyze which carbon pools were specifically affected by the fires. Furthermore, a close look on the regeneration of forests after fire was taken in order to better understand how carbon stocks recreate after disturbance regimes. In order to enable this type of analysis, it was crucial to stratify the project area into homogenous carbon density classes. This was done by identification of strata with GIS, analysis of existing data, designing of a sampling framework and calculation of carbon contents with the help of the data collected in the field. The results described the profound effect forest fires had on the carbon storage in the National Park Sierra del Lacandón. Comparing the non-affected forest and the areas with the most recent fire occurrence showed a mean carbon loss of 53 percent. Here, trees with a diameter at breast height (DBH) above 10 cm and roots were the main carbon pools and responsible for the largest share of greenhouse gas emissions. Carbon densities showed a high heterogeneity among the sample plots which was mainly due to missing stratification factors. Furthermore the estimation of root biomass and carbon stocks was proven to be unreliable and requires further consideration in future methodologies. Regeneration of forests after fire occurrences was shown to be a considerably long process where after more than 10 years biomass and carbon stocks represented only 58% of corresponding carbon stock levels before the fire. Also here, more stratification factors would have been needed to better analyze regeneration processes after fire since forests were affected very differently.