不同年龄杜香-兴安落叶松林粗木质残体贮量及特征

Storage and characteristics of coarse woody debris in different aged natural Ledum palustre-Larix gmelinii forests in Daxing’anling Mountains of Northeast China

以大兴安岭杜香-兴安落叶松林为对象,采用2类标准分析不同年龄林分粗木质残体(CWD)的物种组成、径级结构及腐烂等级,揭示CWD特征及贮量的变化。结果表明:Harmon标准计算的密度、体积和生物量为350～659株·hm-2、2.64～38.27m3·hm-2和1.13～8.52t·hm-2,分别比LTER标准高出52.07%～92.38%、17.44%～63.13%和16.88%～22.11%。随着林分年龄的增加,Harmon标准计算的CWD密度呈"U"型分布,体积和生物量均呈近似正态分布;LTER标准计算的CWD密度从中龄林开始逐渐上升,体积和生物量则逐渐降低。随着林分年龄的增加,2类标准计算的腐烂等级高的CWD密度、体积和生物量比例均逐渐增加,其中幼中龄林以Ⅰ-Ⅱ级腐烂为主,近成熟林以Ⅱ-Ⅲ级为主。群落由兴安落叶松和白桦构成,兴安落叶松CWD在数量、体积和生物量上均占76%以上。

By using two kinds of criterions, this paper analyzed the species composition, diame ter class structure, and decay class of coarse woody debris （CWD） in different aged Ledum pal ustre-Larix gmelinii forests in Daxing＇ anling Mountains of Northeast China, aimed to explore the characteristics and storage of the CWD. The density, volume, and biomass of the CWD derived from the Harmon criterion were 350-659 trees · hm-2, 2.64-38.27 m3 · hm-2, and 1.13-8.52 t · hm-2, being 52.07% -92.38% , 17.44% -63.13% , and 16.88% -22.11% higher than those derived from the LTER criterion, respectively. With increasing stand age, the density of the CWD derived from the Harmon criterion exhibited a ＂U＂ distribution, and the volume and biomass of the CWD showed a near normal distribution, while the density of the CWD derived from the LTER criterion increased gradually from middle age forest, and the volume and biomass of the CWD decreased. The proportions of the density, volume, and biomass of the CWD at high decay class derived from the two criterions increased gradually with the increase of stand age. The decay classes of the CWD in young and middle aged forests were mainly of grades Ⅰand Ⅱ , while those in near-mature and mature forests were of grades Ⅱ and Ⅲ. The population was composed of L. gmelinii and Betula platyphyUa, and the CWD density, volume, and biomass of L. gmelinii occupied above 76%.