Evaluation of carbon accounting models for plantation forestry in South Africa

[摘要] ENGLISH ABSTRACT: The role that forestry plays in climate change mitigation is well recognized by countries thatratified the Kyoto protocol agreement. Though climate change mitigation strategies provide astrong incentive to quantify current patterns of forest carbon sources and sinks, this exercise(carbon accounting) is not as simple as it sounds. This is proven by the vast number oftechniques and methodologies available, from models to softwares programmes created inresponse to the need to estimate carbon sequestration.The study aimed at gaining an understanding of the current carbon sequestration estimationmethodology and models in use by the South African Forestry Industry. A survey wasundertaken amongst forestry industry stakeholders in which 77% of respondents agreed to theneed for a carbon sequestration model for South Africa. This model should have qualities thatthe forestry industry and all stakeholders agreed with. .A search of freely available models and software was conducted. The aim was to find freelyavailable model(s) that would be readily applicable and adoptable to South Africanconditions.A Multi Criteria Analysis was carried out using 'ideal qualities for a carbon model asweighting. This resulted in the selection of two models, CASMOFOR and CBM CFS 3,which obtained the highest sum product total from the analysis. These together with FICAT,which came as a recommendation from the questionnaire survey, were compared in theanalysis.Carbon values were calculated from yield table volumes by Kotze et al. (2012). A conversionof these volumes to biomass and carbon was done using Dovey (2009) biomass expansionfactors and a biomass to carbon conversion value of 0.5 g C/g dry matter, followingprocedures by Matthews (1993).The first comparison was made on how the model results related to the yield table estimatesfrom Kotze et al. (2012). When carbon values were compared per hectare, it was found thatthe FICAT model differed significantly from the rest.A second comparison looked at the models' prediction of the carbon accumulated in NCT'sEnon plantation outside Pietermaritzburg. The Hungarian model, CASMOFOR, was thebetter predictor as it produced the lowest Mean Squared Error (MSE).Based on the results from the survey and model analysis a number of recommendations canbe made regarding the current carbon accounting situation in South Africa. One of the main recommendations is that information sharing among the industry's stakeholders shouldimprove if the industry is to reach consensus on which methodology to adopt in their businesspractices.

[发布机构] Stellenbosch University