三江平原丘陵区长白落叶松单木立枯枝研究

Characteristics Of Standing Deadbranch On Single Tree In Larix Olgensis Plantation On Hilly Area Of Sanjiang Plain

以三江平原丘陵区13～48a生长白落叶松人工林为对象，实测了长白落叶松的树高、枝下高、死枝高和立木枯枝现存量，分析了其变动状况和影响因素，建立了相应的统计模型。同林分不同立木的枝下高、死枝高、冠长和立木枯枝现存量的变动系数分别为5．43％～27．84％、6．97％～51．78％、11．80％～25．63％和28．88％～137．57％；随林龄变化，枝下高与树高之比、死枝高与树高之比均呈先增加后稳定的s型曲线变化趋势，冠长与树高之比表现出先降低后稳定的变化趋势；随林龄增加，枝下高、冠长、死枝高和立木枯枝现存量均表现出S型曲线变化趋势；枝下高和冠长的主要影响因素是树高，死枝高和立木枯枝现存量的主要影响因素分别是林龄和胸径。

The tree height （H）, height under living branch （HLB）, height under dead branch （HDB） and stand- ing deadbranch storage （SDS） were measured by surveying analytical trees of 13 ～ 48 age in Larix olgensis planta- tions of Mengjiagang forest farm on hilly area of Sanjiang plain. The coefficient of variance （ CV）, influencing fac- tor and empirical model of HLB, HDB and SDS were studied. The CVs of HLB, HDB, crown length （CL） and SDSin the same stand were 5.43%～27.84%, 6. 97% -51.78%, 11.80% -25.63% and 28.88% - 137.57%, respectively. With forest age＇ increasing, the ratios of HLB to H （HLBH） and HDB to H （HDBH） were increasing, but the ratio of CL to H （CWH） was decreasing. The sigmoid models could fit the relationship be- tween HLBH, HDBH, and CWH to forest age. The HLB, CL, HDB and SDS were increasing with forest age increasing at sigmoid trends. The mainly influencing factors of HLB, CL, HDB and SDS were H, forest age and DBH, respectively.