东北林区4种主要森林类型直径结构的比较研究

分析了东北林区4种森林类型即阔叶混交林、针阔混交林、柞树林和长白落叶松人工林的直径结构特征,运用正态分布、Weibull分布、Gamma分布以及对数正态分布4种分布函数对4种森林类型的林分的直径分布进行了拟合,同时用卡方统计量对4种分布进行了检验,拟合结果和检验结果一致表明:在4个拟合分布函数中,阔叶混交林和柞树林用Gamma分布拟合直径分布效果更好,针阔混交林和长白落叶松人工林用Weibull分布拟合直径分布效果更好.     

柞树林直径分布模拟研究

柞树林是我国东北地区分布较广的次生林,对它的研究具有重要意义。分析了两种类型柞树林的直径结构特征,并分别利用4种分布函数即正态分布、Weibull分布、Gamma分布以及对数正态分布对两种类型柞树林的直径分布进行了拟合,同时用卡方统计量对4种分布进行了检验,拟合结果和检验结果表明:在4个拟合分布函数中,Gamma分布用于拟合两种类型柞树林的直径分布效果更好。     

闽南山地马尾松人工林林分直径结构规律研究

以福建闽南山地马尾松人工林2块样地资料为依据,应用正态分布,对数正态分布,Weibull分布,β分布,Γ分布拟合闽南马尾松人工林直径分布的规律,并对适用性进行分析、比较,选出最适合于拟合及预测该林分直径结构的分布模型,并用卡方统计量对5种分布进行检验,结果表明:β分布描述闽南马尾松人工林的直径分布效果最好.     

青石冈林场木荷直径结构研究

以湖南青石冈林场木荷人工林为研究对象,分析了木荷直径结构规律。运用威布尔分布(Weibull)、正态分布、对数正态分布和伽马(Gamma)分布进行直径拟合,并结合X2对拟合结果进行检验,结果表明:木荷林分平均胸径为10.4cm,在5.1～37.1cm之间变动,全距32.0cm,径阶分布范围不大;小径阶的林木数量居多(6～12cm),累计百分比已达到83.7%;4种分布函数中,威布尔分布拟合效果最好,其次是对数正态分布,但两者的差异不大,均可用于预测木荷林直径结构。     

樟树苗期直径结构Weibull分布的研究

应用Weibull分布函数对樟树苗期直径分布进行了拟合，结果表明Weibull分布的拟合效果很好。探讨直径分布规律对于樟树的科学管理具有重要的意义。     

东北林区臭松次生林直径结构规律研究

以吉林汪清林区臭松次生林为对象,分析了臭松次生林的树种组成和直径结构规律。采用威布尔分布(Weibull)、伽马(Gamma)及对数正态分布(logarithmic normal)进行直径拟合并进行卡方检验,研究表明:臭松林分平均直径为15.1cm,最小直径为5.1cm,最大直径为47.1cm,6—28径阶的林木株数所占比重最多,达75.8%,3种分布函数中,威布尔分布的R2为0.997,卡方(χ2)为6.35,拟合效果最好,伽马分布次之,对数正态分布最差,但前两者的差异不大,故威布尔分布和伽马分布适用于臭松林直径结构预测,可为臭松次生林直径结构和林分密度调整提供理论依据。     

福建不同杉木产区林分直径结构模拟研究

杉木是南方集体林区的主要树种,是我国重要的森林资源,但受区域气候、土壤条件影响,杉木林的直径分布在不同地域上存在较大差异,合适的模拟是进行不同产区林木生长差异比较的重要前提。以福建省为例将杉木产区分为中心产区、一般产区和边缘产区,利用第8次全国森林资源一类清查福建省杉木林样地数据资料,分产区随机抽样224个优势树种为杉木的样地,采用正态分布、韦布尔分布、对数正态分布、伽马分布和Logistic分布5种分布函数对3种杉木产区的林分直径分布进行了拟合,并结合卡方统计量进行检验。结果表明:中心产区和一般产区杉木林用韦布尔分布拟合直径分布精度较高,边缘产区杉木林用伽马分布拟合直径分布精度较高。     

用Weibull分布拟合刺槐林分直径结构的研究

应用三参数Weibull分布拟合刺槐林分林木直径分布，并与正态分布及回归方程Y=ae^b(x-x^-)^2拟合结果对比，表明用Weibull分布拟合效果好，精度高，能描述刺槐林分林木直径分布规律，可反映出实际分布与理论分布接近的程度，有一定的现实意义。     

关于五常市宝龙店林场主要林分类型直径分布的研究

研究应用五常市地区宝龙店林场调查的20块次生林标准地的数据,分析林分的直径分布规律,运用指数分布、正态分布和Weibull分布函数对其进行拟合,用R语言对样地数据进行处理,建立直径回归模型,用分布检验并比较各种分布函数对实际数据的拟合效果。研究结果表明:随着林分树木直径不断增加,林木株数在总体上呈现出减小的趋势。在人工林中,正态分布和Weibull分布的拟合效果较好;在阔叶林中, Weibull分布拟合效果更好。     

粤西地区23个阔叶树种早期生长比较

对南亚热带森林群落恢复标准化示范区23个阔叶树种的早期生长进行了调查与分析。结果表明：23个阔叶树种在本地区有极强的适应性,且在树高、胸径、冠幅生长上均存在着极显著差异,为树种选择提供了依据;米老排、黎蒴栲生长速度最快;红锥、灰木莲、山杜英、锥栗、枫香、樟树生长较快;非洲桃花心木生长速度中等;其他树种生长较慢。     

Extent,distribution and origin of non-native forest tree species in Europe

ABSTRACT

The management of non-native tree species in European forests has a long history, but the information on the current number and geographic distribution of these species in European forests is incomplete and scattered across various datasets. This study aims to perform an inventory of the most frequent non-native tree species growing in European forests and analyse their current extent, geographic distribution and geographic origin. Our results show that at least 150 non-native tree species are currently growing in European forests and provenance trials. The genera represented by largest number of species are Eucalyptus, Pinus, Acacia and Abies. Species growing at the largest areas are Robinia pseudoacacia (2.44 million ha), Eucalyptus globulus (1.46 million ha), Picea sitchensis (1.16 million ha) and Pseudotsuga menziesii (0.83 million ha). In total, non-native tree species in Europe are found in an area of approximately 8.54 million ha, or 4.0% of the European forest area, and the five most abundant species account for up to 77% of this area. The largest number of these 150 species were introduced from North America (71), followed by Asia (45) and Australia (20). North American species occupy by far the largest area.     

Predicting and calibrating diameter distributions of Eucalyptus grandis (Hill) Maiden plantations in Zimbabwe

Diameter distribution models for even-aged Eucalyptus grandis plantations in Zimbabwe were developed using the two-parameter Weibull function. The analysis was based on data from Correlated Curve Trend (CCT) experiments replicated on four different sites. Parameters of the Weibull distribution were predicted using stand characteristics as regressors. Two sets of parameter models were estimated: a set with and one without stand basal area as a predictor. Stand variables such as dominant height, age, site index and number of stems were used in both sets. The models were further calibrated to result in a given number of stems and stand basal area simultaneously. The usability of constructed models was tested both in prediction of yield in a stand inventory situation and in simulation of growth in connection with different growth models. The results indicated that models not including stand basal area produce considerably less precise stand volume estimates compared to models including also stand basal area. Calibration improved the accuracy of diameter distribution models. In growth simulation diameter distribution models can be connected both to single tree growth models and to stand projection models. The usability of calibration in growth simulation depends on the accuracy of the prediction of stand characteristics.     

行道树树种结构及健康评价的研究

采用实地观测方法,研究了长春市主城区(环城路内)78条主要道路行道树的树种结构特征与健康状况,结果表明:垂柳、新疆杨和糖槭是研究区内行道树的主要树种,分别占研究区树木总株数5 897株的12.79%、10.99%和10.53%;平均密度为276株·hm-2,平均胸径、平均树高、平均活枝下高和平均冠幅分别为11.7 cm、742 cm、201 cm和347 cm。环城路以内行道树43.96%的植株处于亚健康等级;健康和不健康植株分别占17.49%和10.99%;中等健康植株占27.66%。     

青冈栎次生林主要树种空间分布格局及其关联性研究

青冈栎次生林作为亚热带地区次生林的典型代表之一,研究其林分内主要树种的空间分布格局及关联性,可以更好地开展次生林经营指导工作。通过对9块青冈栎次生林样地的调查,运用空间点格局分析方法对其林分内主要树种的空间分布格局及种间关联性进行研究。结果表明:1)以完全空间随机模型为零假设时,林分整体的空间分布格局在0~12m尺度上呈聚集分布,在12~25m尺度呈随机分布,大于25m尺度趋于均匀分布态势;以异质泊松模型为零假设时,林分整体的空间分布格局总体上呈随机分布;2)样地内青冈栎、杜鹃和拟赤杨在小尺度上呈聚集分布,随尺度增加呈随机分布或均匀分布;甜槠、杉木和檵木基本在所有尺度呈随机分布。3)样地内建群种青冈栎与杉木在所有尺度呈负相关,与其它主要树种在小尺度呈负相关,随着尺度增加变为不相关;所有伴生树种的种间关联性在0~2m为负相关,在其它尺度上不相关为主。青冈栎次生林的空间分布格局受生境异质性的影响,且空间分布格局和主要树种间的关联性随空间尺度的不同而变化。     

Water consumption of a single tree from the main afforestation tree species in Western Shanxi Province, a loess area

Water is the key factor in vegetation growth in a loess area. Researchers have been keen on the study of tree transpiration for a long time. To provide a scientific basis and practical instruction for vegetation reconstruction and recovery in a loess area, the paper measured and calculated the water consumption of potted Platycladus orientalis, Robinia pseudoacacia, Armeniaca vulgaris and Pyrus hopeiensis separately during the growing season (from Apr. to Nov.). The four were the main afforestation species in a loess area of western Shanxi based on the principle of water balance. Using data on soil water dynamics and the range of available moisture on potted mature trees, the relationship between water supply and consumption and soil moisture availability and deficit state were analyzed. Several conclusions are listed as follows: 1) In the dry year (2002), during the growing season the precipitation was 430.7 mm and the water consumption of potted trees was from 430 to 490 mm. More water consumption and less available water supply occurred, showing a serious water deficiency. In the rainfall-rich year (2003), during the growing season the precipitation was 870.2 mm and the water consumption of potted trees was from 480 to 515 mm. Due to the uneven distribution of rainfall, the water budget balance was slightly affected in May and November. 2) The curves of soil water content of different species had similar annual changes, although the trends were different in the same month, and those of the same tree species in different test plots also had different trends in the same month. 3) Non-available soil water content of Platycladus orientalis, Robinia pseudoacacia, Armeniaca vulgaris and Pyrus hopeiensis was less than 8.0%, 8.4%, 9.2% and 9.7% respectively, which indicated that Pyrus orentalis used water more efficiently than the others. In the dry year (2002), for several months, soil water content of potted trees was lower than its threshold value for non-available soil water content, which could influence the healthy growth of trees. After supplements of precipitation of winter in the year and spring in the next year, soil water content was higher than the lower limit of soil readily available moisture content, which implied that a balance between inter-annual water supply and consumption could be maintained. __________ Translated from Scientia Silvae Sinicae, 2006, 42(9): 18–23 [译自: 林业科学]     

4个北美树种在辽西地区的引种试验研究

为了丰富本地区的树种资源,满足园林绿化对树种多样性的需求,从物候期、生长节律及光合特性等几个方面对美洲朴、毛核木、银水牛果、西部沙樱这4个北美树种在辽西地区的引种适应性进行了研究。结果表明,4个树种的萌芽、展叶期均较北京地区有所延后,花期则提前;美洲朴未见开花坐果,银水牛果秋季叶片不变色;4个树种株高、地径、枝条的快速生长期为5—7月份,美洲朴和毛核木具有明显的越冬枯梢现象,翌年生长多以萌蘖条为主;西部沙樱和银水牛果具有较强的光合作用和较高的水分利用效率,是辽西地区园林绿化可尝试引入的优良观赏树种。     

Height–diameter equations for boreal tree species in Ontario using a mixed-effects modeling approach

Height–diameter relationships based on stand characteristics (trees/ha, basal area, and dominant stand height) were investigated for balsam fir, balsam poplar, black spruce, jack pine, red pine, trembling aspen, white birch, and white spruce using data from permanent growth study plots in northern Ontario, Canada. Approximately half the data were used to estimate model parameters with the rest used for model evaluation. Multiple Chapman–Richards functions with parameters expressed in terms of various stand characteristics were fit to determine the best models for predicting height.     

Environmental correlates of distribution of the 25 broad-leaved tree species indigenous to Guangdong Province,China

Twenty-five tree species indigenous to Guangdong Province were chosen in this study to portray their distribution patterns in relation to environmental factors. Both data of species distribution and environmental factors were tabulated based on a digitized map of Guangdong Province gridded at 0.5° latitude × 0.5° longitude. Grid-based diversity was mapped using DMAP, a distribution mapping program, and horizontal patterns were assessed using Kruskal-Wallis tests. The diversity center of the indige- nous tree species under study is located north of 23° N. These tree species exhibit significant latitudinal variation (P = 0.007 4), but no significant longitudinal difference (P = 0.052 2). Non-metric Multidimensional Scaling (NMS) identified five different ecological species groups, while Canonical Correspondence Analysis (CCA) showed the distribution of tree species along each of the five envi- ronmental gradients. An understanding of the environmental correlates of distribution patterns has great implication for the introduc- tion of the indigenous tree species for afforestation.