Evaluation of carbon accumulation in the Kandelia obovata Sheue, Liu & Yong plantation in northern Vietnam

This study was conducted to evaluate carbon accumulation in a mangrove plantation containing one species of Mangrove tree (Kandelia obovata Sheue, Liu & Yong) in Giao Thuy District, Nam Dinh Province, Vietnam. Sixteen sample plots were established and surveyed from December 2008 to May 2010 in order to determine the amount of carbon present in the trees and forest soil.
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Evaluation of carbon accumulation in the Kandelia obovata Sheue, Liu & Yong plantation in northern Vietnam JOURNAL OF SCIENCE OF HNUE Chemical and Biological Sci., 2012, Vol. 57, No. 8, pp. 43-55 This paper is available online at http://stdb.hnue.edu.vn EVALUATION OF CARBON ACCUMULATION IN THE Kandelia obovata SHEUE, LIU & YONG PLANTATION IN NORTHERN VIETNAM Mai Sy Tuan Faculty of Biology, Ha Noi National Universuty of Education Abstract. This study was conducted to evaluate carbon accumulation in a mangrove plantation containing one species of Mangrove tree (Kandelia obovata Sheue, Liu & Yong) in Giao Thuy District, Nam Dinh Province, Vietnam. Sixteen sample plots were established and surveyed from December 2008 to May 2010 in order to determine the amount of carbon present in the trees and forest soil. The amount of CO2 released from the forest soil was estimated once a month using a KIMOTO-HS7 gas absorption machine. The amount of carbon accumulation was calculated from estimated variables. The results show that the amount of carbon accumulated in trees and forest soil is higher than that of emitted CO2 . The annual amount of carbon that is accumulated by K. obovata plantations is equivalent to the amount of CO2 emitted, and this amount increases as the forest ages, reaching the highest value in the 9 year old forest (27.138 ton/ha/year) in this present study (a CO2 equivalent of 99.596 ton/ha/year (39.35%). The least amount of CO2 emitted was observed in the 1-year old forest (2.207 ton/ha/year), a CO2 equivalent of 8.099 ton/ha/year (3.20%). Therefore, a K. obovata plantation can accumulate a large amount of carbon and function as a carbon sink and reduce the amount of CO2 in the atmosphere. This study presents scientific data that could be used to justify the implementation of mangrove plantation projects under CDM and PES programs along the Vietnamese coastline that could protect the environment, inhibit climate change, improve living standards, alleviate hunger and reduce poverty among local populations. Keywords: Mangrove plantation, Kandelia obovata, carbon accumulation, Northern Vietnam.Received September 10, 2012. Accepted November 2, 2012.Contact Mai Sy Tuan, e-mail address: tuanmaisy@yahoo.com 43 Mai Sy Tuan1. Introduction Mangrove forests were found along the coastlines in most countries in the tropicsand subtropics and many still remain or have been rather recently planted. Tropical forestsin general are a disproportionately important component in the global carbon cycle andare thought to represent 30 - 40% of the terrestrial net primary production and storageof carbon [4, 10]. Although, mangrove forests represent only a small fraction of totaltropical forest area, the amount of carbon accumulated in the biomass of mangrove foresttrees and/or sediments is significant. In addition to this accumulation, the mangroveecosystem also includes a carbon release process that involves the aqueous environmentand particularly the sediment due to the decomposition of microorganisms. Although a large number of studies have been done which have examined carbonaccumulation in natural mangrove ecosystems around the world [9], there is littleinformation available about carbon accumulation in man-made mangrove plantations. Vietnam’s 3260-km long coastline and dense river system with abundant alluvialeffluent has the potential to support a substantial area of mangrove trees. Eleven yearsago, in 2001, the Forest Inventory and Planning Institute carried out a national forestinventory [5] and at that time it was estimated that there were 156,608 ha of mangrovetrees in Vietnam, about two thirds of that being plantation forest trees. This current studyhas been carried out in order to evaluate carbon accumulation in mangrove plantations innorthern Vietnam, the specific objectives being: 1) to evaluate the efficacy of mangroveplantations as carbon sinks, 2) to propose an effective methodology for measuring carbonaccumulation, 3) to contribute to the means of valuating carbon credits based on theKyoto protocol approved in 2002 regarding Clean Development Mechanism (CDM) andPayment for Environmental Services (PES) carbon options and 4) to help policy makersand managers formulate an integrated management plan regarding mangrove plantationareas that would result in increased carbon accumulation.2. Content2.1. Materials and methods2.1.1. Study site This study was conducted from December 2008 to May 2010 in plantations of K.obovata Sheue, Liu & Yong mangrove trees (other mangrove/associated species werenot found). The trees are now 1, 5, 6, 8, 9, and 12 years old and were planted in theGiao Lac Commune, Giao Thuy District, Nam Dinh Province, in Northern Vietnam.Giao Lac Commune is situated between 20◦ 13’- 20◦ 15’ latitude and 106◦ 15’- 106◦ 30’longitude. The commune is bordered by the Giao An Commune to the north, the GiaoXuan Commune to the south and the sea to the east (Figure 1).44 Evaluation of carbon accumulation in the Kandelia obovata Sheue, Liu & Yong plantation... Figure 1. Study site in the coast of northern Vietnam Giao Lac Commune is in the Xuan Thuy Ramsar Site which is a buffer zone. At thistime in the Giao Lac commune, approximately 407.7 ha have been planted in mangrovetrees. The mangrove ecosystem here receives a large amount of alluvial material from theRed River and the mangrove habitat soil is basically mud mixed with clay and sand ...