典型阔叶红松林叶面积指数的空间异质性 / Spatial heterogeneity of leaf area index in a typical mixed broadleaved-Korean pine forest in Xiaoxing'an Mountains of northeastern China
【目的】探讨叶面积指数(LAI)的空间异质性及其影响因素,以期为准确地获得局域、区域等大尺度上LAI的空间分布特征提供参考依据。【方法】依托黑龙江丰林国家级自然保护区30 hm2典型阔叶红松林动态监测样地,首先通过LAI与胸高断面积间的经验模型得到阔叶红松林内红松、冷杉、紫椴、硕桦、裂叶榆和色木槭6种主要树种及林分水平上的LAI,然后采用半方差函数和Kriging空间插值等地统计学方法分析LAI的空间异质性特征以及与地形因子(海拔、坡度、坡向和曲率)的相关关系。【结果】主要树种LAI的变异系数均大于10%,具有中等或强变异性,且变异程度表现为裂叶榆>硕桦>紫椴>红松>色木槭>冷杉。红松LAI的空间结构比(块金值(C0)/基台值(C0+C))为0.50,具有中等程度的空间自相关,而其他5个树种的比值均低于0.25,具有强烈的空间自相关;主要树种LAI的变程范围为24 m(紫椴)～126 m(红松)。红松、裂叶榆和色木槭的空间异质性具有较明显的各向异性结构特点,且红松的LAI在240 m尺度范围内时,东西方向(0°)上的空间异质性明显大于南北方向(90°),240 m以后出现相反的结果。红松的LAI与海拔、坡度、坡向和曲率4个地形因子均呈极显著正相关(P<0.01),其他树种的LAI与地形因子也表现出不同的相关关系。【结论】LAI的空间异质性不仅与研究尺度相关,而且与方向相关;地形因子对LAI空间分布的影响存在种间差异,但整体来看,4个地形因子均对LAI的空间分布存在显著影响
[Objective] Exploring the spatial heterogeneity of leaf area index (LAI) and controlling factors is to provide a solid foundation for obtaining the distribution of LAI in local or region scales. [Method] Based on a 30 ha (500 m×600 m) mixed broadleaved-Korean pine (Pinus koraiensis) forest at Fenglin National Nature Reserve in Xiaoxing'an Mountains of northeastern China, which was divided into 750 subplots by 20 m×20 m, all woody species with a diameter at breast height≥1 cm were identified and surveyed. We first obtained LAI values of six major species (e.g., P. koraiensis, Abies nephrolepis, Tilia amurensis, Betula costata, Ulmus laciniata and Acer mono) based on empirical models between LAI and basal area for each subplot. We then analyzed the spatial heterogeneity of LAI for major species and the forest stand by geo-statistic methods (semivariogram and Kriging interpolation), and the correlations between LAI and topographic variables (e.g., elevation, slope degree, slope aspect and curvature) were also explored. [Result] The variation coefficient of LAI for six major species was all larger than 10%, and can be considered relatively moderate or strong, and degrees of variation were U. laciniata > B. costata > T. amurensis > P. koraiensis > A. mono > A. nephrolepis. The ratio value of nugget (C 0 ) by sill (C 0 +C) was 0.50 for P. koraiensis, showing moderate spatial autocorrelation; in contrast, the ratio values for other five species were all lower than 0.25, showing strong spatial autocorrelation. The range (A) values ranged from 24 m (T. amurensis) to 126 m (P. koraiensis) of LAI for six major species.The clearer anisotropic structures were exhibited by LAI values for P. koraiensis, U. laciniata and A. mono, in contrast to other species; additionally, the spatial heterogeneity of LAI in east-west (0°) direction was clearly larger than that in south-north (90°) within 240 m for P. koraiensis, and showed opposite results when larger 240 m. The LAI was significantly positively correlated with all elevation, slope degree, slope aspect and curvature for P. koraiensis (P<0.01), and different correlations between four topographic variables and LAI values were showed for other five species. [Conclusion] Spatial heterogeneity of LAI is correlated with not only study scale but also direction. The influence of topographic variables on LAI distribution varies with species, but the four topographic variables all significantly affected LAI distributions for a forest stand.
Abstract in Chinese and English, paper in Chinese only