中亚热带红壤丘陵区湿地松枝条生长规律

Branch growth of Pinus elliottii in the hilly red-soil area of the mid-subtropical climatic zone

在综述国内外林木枝条相关研究成果的基础上,通过对江西省泰和县境内中国科学院千烟洲试验区湿地松Pinus elliottii枝条生长状况的调查,分析了湿地松树冠各轮枝层枝条生长规律,并建立了枝条生长与气象因子的相关关系回归模型。结果表明,同一年份枝条节间长、基径生长量随轮枝层的下降呈波动式下降趋势。枝条基径随轮枝层的下降不断增大,而在靠近树冠底部位置略微减小,各轮枝层枝条材积分布为右偏正态分布曲线,说明大枝条主要集中在冠层中下部。大量枝条样本材积与枝条基径的平方和枝条长度乘积的拟合精度只有0.67,说明该模型更适合拟合小枝条的材积。采用一元线性回归方程拟合枝条节间长、基径生长与枝条生长期主要气象因子的相关关系,回归方程的相关关系判定系数都在0.96以上(P<0.01),偏回归系数显著性检验的概率P均小于0.01。由回归方程的偏相关系数可知,枝条节间长生长量主要取决于冠层相对湿度,基径生长量与≥10℃积温呈负相关,与降水量呈正相关。

From a review of the Pinus elliottii （mash pine） domestic and overseas literature on branching, the branch growth at the whorls was analyzed at the Qianyanzhou Experimental Station of the Chinese Academy of Sciences in Taihe County, Jiangxi Province, China and its relationship with several meteorological factors was determined. Branch growth for internode length （IL） and basal diameter （BD） was determine by vernier caliper, and their partial correlations with respect to the whorls were calculated. Additionally, the response to these meteorological factors during the growing periods was described in a multiple linear regression model. Results showed that branch IL growth for a given year declined from the upper whorls to the lower whorls. Also, branch BD increased gradually from the upper whorls to the lower whorls, but slightly declined near the base of the crown. Distribution of the annual total branch volume was well fitted to skewed left normal distribution curves. This showed that large branches were mainly concentrated in the middle-lower part of crowns. The linear regression accuracy for branch volume versus （BD2 x branch length） was not very strong （r^2 = 0.45）. However, the adjusted R^2 of the multiple linear regression equations for IL and BD with several meteorological factors were all highly significant （ 〉 0.96） （P 〈 0.01）, and the partial correlations were all highly significant （P 〈 0.01）. The partial correlations showed that IL growth mainly depended on canopy relative humidity. Also, BD growth was negatively correlated with a cumulative temperature of ≥ 10 ℃, while it was positively correlated with total precipitation. [ Ch, 6 fig. 41 ref. ]