应用湿烧法对广东地区8种主要乔木树种(马尾松、速生相思、杉木、桉树、湿地松、硬阔类、软阔类、黎蒴)的碳含量进行了测定,并对不同树种、不同器官、不同径阶、不同树干高度的碳含量进行分析。结果表明:1)不同树种碳含量高低依次为湿地松>杉木>马尾松>速生相思>硬阔类>桉树>软阔类>黎蒴;针叶树的碳含量大于阔叶树;2)不同器官碳含量大小关系为树叶>树枝>树皮>树干>树根,器官碳含量遵循由上到下,呈现由外到里逐渐减少的趋势;3)不同树种不同树干高度位置碳含量十分接近,变异系数均在3.64%以内;4)研究区域树木碳含量受径阶影响很小,碳含量变化幅度小,同一树种不同径阶下不同器官的碳含量变化情况呈现多样性,同一树种内不同径阶和不同高度位置碳含量呈先上升后下降的趋势。径阶与树干高度位置碳含量没有相关性,但总体上相同高度位置下样品碳含量随着径阶的增加先上升后下降。以上结果说明,不同树种之间,相同树种内部不同器官之间,以及不同特性相同树种之间碳含量存在差异性。对各地区、各树种、各森林生态系统的碳含量进行全方位精确测定,可为提高估算其碳储量的准确度提供科学依据。

Carbon content values of eight tree species in the region,i.e.,Pinus massoniana,fast growing acacia,chinese fir,eucalyptus,slashpine,hardwood,softwood,and Castanopsis fissa,were measured based on the wet burning approach.In addition,carbon content of these trees with respect to several potential influencing factors,i.e.,tree species,tree organs,diameter grades,and vertical trunk positions,were analyzed.Experimental results showed that:1)with respect to tree species,the carbon contents in descending order are:slash pine > chinese fir > Pinus massoniana > fast growing acacia > hardwood > eucalyptus > softwood > Castanopsis fissa .2)With respect to tree organs,the descending carbon contents are:leaves>branches>bark>trunks>roots,and the carbon content decreased when the positions of these organs located from top to bottom or from outside to inside.3)With respect to vertical trunk positions,the carbon contents of all eight species are very close,and coefficients of variation for those species are all less than 3.64%. 4)With respect to diameter grades,variation amplitudes of carbon contents of sampled trees in Guangdong are relatively small.However,for the same tree species,the carbon contents of different organs from the same tree species varied with their diameter grades,and the carbon content increased firstly and then decreased along with the increasing of diameter grades or vertical trunk positions.No correlations were observed between the rates of diameter grades and that of vertical trunk positions.For samples under the same vertical trunk positions,the carbon content rised in the beginning and then descended with the rises of diameter grades.In general,significant differences in carbon content were perceived among different tree species,or different tree organs of the same species,or distinct influencing factors of the same species.The accurate determination of carbon contents in various areas,tree species and forest ecosystems can provide a scientific basis for improving the accuracy of estimating their carbon reserves.