天山云杉球果大小性状的地理变异规律

选择新疆境内天山山脉从西到东处于不同经度位置(81°05'-93°41.5'E,约12个经度范围)5个地点(昭苏、巩留、乌苏、乌鲁木齐和哈密)的天山云杉林进行垂直样带取样测定,分析天山云杉球果大小性状(长、宽及长宽比)随海拔梯度与经度的地理变化规律,以期为天山云杉种群保护、优良种源选育及其合理利用提供依据.结果表明:同一经度位置不同海拔范围内天山云杉球果大小性状发生不同的变化.天山云杉的球果长和球果长宽比随着海拔的增加总体上呈现逐渐减小的趋势,而球果宽则总体上随海拔梯度变化不显著.各经度位置天山云杉球果宽较球果长的性状稳定性高.天山云杉球果性状随海拔、经度和坡度的变化而发生变异,球果长的变异主要受海拔和坡度的影响,球果宽的变异则主要受经度的影响,而海拔、经度、坡度对球果长宽比都有显著影响.     

基于贝叶斯模型平均法构建杉木林分蓄积量生长模型

[目的]探究杉木林分蓄积量变化的影响因素,为在气候变化背景下科学经营管理杉木人工林提供理论支撑。[方法]以福建邵武卫闽林场的杉木(Cunninghamia lanceolata)人工密度试验林为研究对象,分别利用贝叶斯模型平均法(BMA)和逐步回归法(SR)构建杉木林分蓄积量与林分变量因子(包括初植密度、每公顷胸高断面积、每公顷株数、平方平均胸径、林分优势高、年龄)和气候因子(包括年均气温、最热月平均温度、最冷月平均温度、年均降水量、年均湿热指数、低于0℃天数、夏季平均最高温度、冬季平均最低温度、春季平均气温)的关系模型。[结果]杉木林分蓄积量随着每公顷胸高断面积、平方平均胸径、林分优势高、年龄、夏季平均最高温、春季平均温和低于0℃天数的增加而增加,对于诸多的影响因子,SR法所确定的模型并不在BMA选出的后验概率较高的前5个模型中,模型表现出一定的不确定性,从模型后验概率角度看,SR模型精度较低。[结论]杉木林分蓄积量受到林分变量因子和气候因子的显著影响。相比于SR法,在构建杉木林分蓄积量模型方面,BMA方法考虑了模型的不确定性,模型表现更好。     

毛白杨主要林分因子生长及相关关系研究

该文在河北省范围内调查片状和带状毛白杨林分标准地 14 9块 ,研究林分平均胸径、平均高、胸高断面积、蓄积等主要林分因子的生长情况 ,并建立了主要因子的生长模型和相关关系模型 ,可用于毛白杨林分生长预测和评估     

青海云杉林生物量及地上径向密度随海拔的变化特征

以祁连山乔木建群种青海云杉(Picea crassifolia)为研究对象,通过野外调查取样和室内试验分析,研究了青海云杉林分因子、生物量及地上径向密度沿海拔梯度的变化特征,为探索祁连山水源涵养功能提供科学依据。结果表明:树高随着海拔的升高呈现先增加后减小的趋势,2 800 m处树高最大,2 900 m处树高最小,平均胸径随着海拔的升高呈现递增的趋势,3 100 m处胸径最大,2 700 m处胸径最小;林分密度随着海拔的升高呈现递减趋势,2 700 m处林分密度最大,3 100 m处林分密度最小。各海拔区段树高和平均胸径差异不显著,各海拔区段林分密度差异显著。青海云杉地上生物量随着海拔的升高呈现先减小再增大的趋势,海拔2 900 m的青海云杉地上生物量最少,地下生物量随着海拔的升高先减小再增大,变化幅度较为平缓,海拔3 100 m地下生物量最大。地上径向密度随着海拔的升高呈现先减小后增大的变化趋势,海拔3 100 m地上径向密度最大,海拔2 800 m地上径向密度最小;海拔3 100 m是青海云杉的最佳生长海拔区段,最能反应森林水源涵养能力的强弱。     

闽中山地湿地松不同立地条件和不同密度的经营效果研究

通过对21、22年生的闽中湿地松人工林不同造林密度和不同立地条件的生长效果研究,结果表明:坡位、表土层厚度对优势木树高有显著影响,但对林分平均树高无显著影响;坡向(阴、阳坡)对平均胸径存在显著差异,且阳坡明显优于阴坡。不同经营密度的林分平均胸径、单株材积差异显著,且随密度增大而减少;冠幅随密度增大而减少;在合理密度范围内,单株胸径、材积随密度增大而减少,但蓄积量却随密度增加而增大。     

海拔和造林密度对马占相思人工林生长的影响

以1994年种植在广东省龙眼洞林场的马占相思人工林为材料,调查5,10和15a生的树高、胸径和蓄积量,研究海拔和造林密度对生长量的影响。结果表明,海拔（0～500mm）对马占相思胸径生长无显著影响,但对5a生的树高、5和10a生的蓄积量有显著影响,其中250m〈海拔≤500m时的林分蓄积量最大;3种造林密度（800,1335和1998株／hm^2）对树高、胸径和蓄积量有较大影响,以造林密度为1335彬hm^2的林分蓄积量增长最快。林分内存在不同程度的海拔与造林密度交互作用,这种互作对胸径和蓄积量的影响逐年增强．但在15a生时对树高的影响已．不鼹薯．     

生态环境与赤松兴凯松天然林生长的关系

调查研究结果表明:林龄及土壤类型是制约赤松、兴凯松林分优势木平均高的主导因子;土壤类型、土层厚度及每公顷胸高断面积是影响林分每公顷蓄积年生长量、林分平均高的重要因子;林分平均胸径受林分密度的制药,并受土壤类型、A层厚度、土壤总厚度的影响。     

天山中部天山云杉林地表可燃物载量及其影响因素

【目的】对天山中部天山云杉林地表可燃物载量进行系统调查,分析地表可燃物载量与地形和林分因子的关系,比较不同郁闭度林分可燃物载量差异,为制定科学合理的天山云杉林可燃物管理措施提供科学依据。【方法】在天山中部沿海拔梯度设置48个样地,调查和测定天山云杉林林分的1、10和100 h时滞地表可燃物载量以及地形和林分因子,采用相关分析方法分析地表可燃物载量与林分和地形因子的关系,利用多元线性回归方法建立可燃物载量估测模型。【结果】天山云杉林1、10和100 h时滞及总地表可燃物载量平均分别为1.49±1.00、2.69±1.05、2.06±0.29和6.24±1.21 t·hm~(-2)。高、中和低郁闭度天山云杉林地表总可燃物载量分别为12.09±3.13、4.29±2.35和2.34±0.83 t·hm~(-2)。1 h时滞地表可燃物载量与海拔呈显著负相关(P0.05),与坡度和郁闭度呈显著正相关(P0.05);10 h时滞地表可燃物载量与海拔呈显著负相关(P0.05),与树高和郁闭度呈极显著正相关(P0.05);100 h时滞地表可燃物载量与郁闭度呈极显著正相关(P0.01),与树高呈显著正相关(P0.05);总地表可燃物载量与郁闭度呈极显著正相关(P0.05),与树高和坡度呈显著正相关(P0.05)。【结论】海拔、坡度、树高和郁闭度对天山中部天山云杉林可燃物载量均有一定影响,其中郁闭度影响最显著。林分郁闭度与地表可燃物载量呈正相关。地表可燃物载量在高郁闭度林分最大,在中郁闭度林分次之。由于林内较干燥,凋落物不易分解,导致地表可燃物大量堆积,林内较高的1 h时滞地表可燃物载量使得林分发生林火的可能性增加;从地表可燃物载量的数量和构成来看,天山中部天山云杉林已具备发生森林大火的物质基础。     

寿宁县黄山松林分结构初探

随机抽取65个黄山松林分小班,调查林分相关因子,结果表明,主要分布区黄山松更新良好,种群稳定,但种群密度差异较大,分布格局随时间而变。分别建立林分蓄积量对于密度、胸径、树高之间的相关性数学模型,运行这些回归方程,结果表明,林分蓄积量随密度增加而增加,而胸径和树高则随密度增加而减小。密度是影响林分产量的主导因子。林分现实产量平均水平为74 m~3/hm~2。     

造林密度对材用樟树幼林生长和蓄积量的影响

以7年生不同造林密度樟树人工林为研究对象,通过分析林分平均胸径、树高、枝下高、冠幅、单株材积和蓄积量等指标,探究造林密度对樟树幼林林分生长及林分蓄积量的影响。结果表明:1)随着造林密度的增大,樟树林分平均胸径、冠幅和单株材积均呈现减小的规律,造林密度为833株·hm^-2时平均胸径、冠幅和单株材积均最大;2)造林密度对林分平均树高的影响较小,枝下高随造林密度的增大而逐渐增高,造林密度为2 500株·hm^-2时林分枝下高最高;3)随着造林密度的增大,林分蓄积量呈现先增大后减小的规律,造林密度为1 111株·hm^-2时林分蓄积量达到最大值;4)各密度条件下林分胸径生长过程相似,但胸径生长旺盛期的持续时间随造林密度的增大而逐渐减少,造林密度为833株·hm^-2时胸径生长旺盛期持续时间最长;5)不同密度林分单株材积连年生长量呈先增大后减小的趋势,林分单株材积快速增长期持续时间随造林密度的增大而减少;6)综合考虑,樟树人工林适宜造林密度为1 111株·hm^-2,合理造林密度范围为1 111～1 667株·hm^-2。     

Altitudinal patterns of the flora of seed plants of Dawei Mountain in Yunnan Province, south China

Altitudinal gradient incorporates multiple resource gradients, which vary continuously in different fashions. It is important to study the mountain floristic patterns along altitudinal gradients, which reveal the regular pattern of the flora along the environmental gradients, the changing trend of biodiversity patterns along the altitudinal gradient, and relevance of biological fitness. To explore the compositional characteristics and ecological significance of floristic patterns along altitudinal gradient in China National Nature Reserve of Dawei Mountain in the southeast of Yunnan Province, field investigations have been made to the flora along the two routes of the southwest slope and the northeast slope of the said reserve, including a vertical vegetation transect. Meanwhile, further investigations have also been made to the flora of Dawei Mountain, which has been accounted for in the literature, as Flora Yunnan, The Seed Plant in Yunnan, and so on. The structural characteristics of the flora and the altitudinal distribution pattern of its floristic components were analyzed. By applying systematic cluster analysis, the altitudinal position of the dividing line of floristic changes along altitudinal gradient was detected, and the effects of the montane climate on the vertical variation of floristic composition were studied. Conclusions were put forward. This paper can be summarized as follows: (1) The obvious boundary that differentiates tropical floristic elements is located at the altitude of approximately 1,500 m; it is reasonable to stipulate the boundary line between tropical rain forests and the evergreen broad-leaved forests. (2) The vertical vegetation spectrum made by cluster analysis shows that humid rain forests are below 700 m a.s.l, montane rain forests are between 700 and 1,500 m, monsoon evergreen broad-leaved forests are between 1,300 and 1,800 m, and montane mossy evergreen broad-leaved forests are above 1,800 m a.s.l. Nonrepresentative montane mossy dwarf forests (above 2,100 m) in the area are distributed in windward sides and in barren land on the mountain slopes. __________ Translated from Acta Phytoecologica Sinica, 2005, 29(6): 894–900 [译自: 植物生态学报]     

Age structure and regeneration of subalpine fir (Abies fargesii) forests across an altitudinal range in the Qinling Mountains,China

Age structure and regeneration dynamics of subalpine fir (Abies fargesii) forest were studied across the altitudinal range in both the north and south aspects of the Qinling Mountains, China. Ages of individual fir trees were determined based on the number of rings counted from cores and the number of years to reach coring height estimated using age–height regression. Fir age structure and regeneration dynamics were similar in both the north and south aspects. A unimodal population age structure was found at the low- and mid-elevations in both aspects, indicating that environmental factors might play an important role in shaping A. fargesii age structure and regeneration at those sites. There was a recruitment pulse during the time period 1830–1890 at each altitudinal site, but no stem recruitment occurred at the low- and mid-elevations in the last century, which might be attributed to the intensive cover of understory bamboo. Fir trees were, however, persistently recruited at the upper limits during the last 150 years, and the fir tree density at the upper limits was significantly higher than that at the lower limits in both aspects. The fir population at the upper limits showed a significant increase in recruitment and stem density relative to the fir population at the low- and mid-elevations in the last century. We propose that the differences in recruitment might promote variations in stand structure and regeneration dynamics of the subalpine fir forests along the altitudinal gradient in the Qinling Mountains, China.     

Altitudinal variability of stand structure and regeneration in the subalpine spruce forests of the Pol’ana biosphere reserve,Central Slovakia

The structure of natural subalpine spruce forest in the Zadná Pol’ana massif of the Western Carpathians was analysed. We focused on the variability of different aspects of stand structure, tree decay and regeneration processes in altitudinal gradient. We used systematic sampling, covering an area of 2 km², to detect even subtle changes in stand structure within one forest type over a range of less than 200 m in elevation. Mean stand density was 290 trees (>7 cm DBH) per hectare, average basal area was 41 m² ha⁻¹, and the volume accumulation in living trees amounted to 500 m³/ha⁻¹. Stand volume decreased by more than 50% between 1,260 and 1,434 m a.s.l. This means for an increase of altitude of 100 m that stand volume decreased by nearly 200 m³. Neither stand density nor basal area was related to elevation. Maximum tree height was strongly correlated to elevation, and it decreased on average by 6 m for each 100 m increment of altitude. No significant changes in the maximum spruce diameter were recorded in relation to the elevation gradient. Spatial distribution of trees was biased toward regularity at lower altitudes. Tree clustering increased with increasing altitude. The stock of coarse woody debris (CWD) decreased slightly along the altitudinal gradient, but changes were not significant. Density of spruce saplings and their number growing on CWD significantly increased across the elevation gradient. Despite the fact that the analysed forest tract was relatively large, highly variable in respect to environmental factors, and that stand volume, spatial structure, and tree height displayed strong variability along the elevation gradient, the diameter structure of stands and regeneration measures were uniform. Our results suggest that the recruitment of new trees in the Zadná Pol’ana subalpine spruce forest is not temporally continuous even at a scale of several square kilometres.     

Climate and seasonal rainfall anomalies along an elevational gradient in the El Sira Mountains,Peru, and their impacts on tree radial growth

The explicit purpose of this study was to characterize climate and vegetation along the western slope of the El Sira Mountains(Peru) and evaluate radial tree growth in response to seasonal rainfall anomalies. From May 2011 until September 2015, we monitored radial stem growth of 67 trees using point dendrometers and measured climate within five sites along an altitudinal gradient. The transect extends from lowland terra firme forests, over submontane forests, late and mid successional montane cloud forests up to exposed elfin forests. Monthly rainfall estimates by the TRMM PR satellite(product 3B42) were highly correlated with our rain gauge observations but underestimate rainfall at high altitudes. Different intra-annual tree growth patterns could be identified within each elevational forest type, showing species with strictly seasonal growth, continuous growth or alternating growth patterns independent of the seasons. Stem growth at each site was generally larger during rainy seasons, except for the elfin forest. The rainy season from October 2013 to March 2014 was extraordinarily dry, with only 73% of long-term mean precipitation received, which resulted in reduced radial growth, again with the exception of the elfin forest. This indicates that montane tropical rain forests may suffer from prolonged droughts, while exposed ridges with elfin forests still receive plenty of precipitation and benefit from receiving more solar radiation for photosynthesis.     

Monitoring managed forest structure at the compartment-level under different silvicultural heritages: An exploratory data analysis in Italy

ABSTRACT

The more and more diffused multifunctional role addressed nowadays to public forests, calls for targeted analysis aimed at highlighting the overall outcome of different practices implemented on the same forest compartment, according to the locally prevailing function. This study was carried out in four Italian beech forests across a latitudinal gradient representative of multiple management history, stand structure, and dominant stand age. We analyze forest structure at the compartment scale before and after silvicultural practices. We aim to explore relationships and similarities between 10 stand attributes (mensurational and structural variables) to identify relevant indicators for the monitoring and management of forest ecosystems. Results indicate changing patterns of correlation and similarity among mensurational variables following practice implementation. A sensitivity gradient to silvicultural practice was finally identified within the four sites investigated as a result of the diverging stand structure. Our approach suggests a way and provides an insight for the design of adaptive forestry management practices required to meet environmental targets, in addition to the already acknowledged supply of primary goods and services.     

Structure and floristic composition of tree stand in tropical forest in the Eastern Ghats of northern Andhra Pradesh,India

The changes in species composition, abundance and forest stand structure were analyzed across altitudinal regimes in tropical for- ests of Eastern Ghats of northern Andhra Pradesh, India. Three 1-ha plots were established with one each in low, medium and high altitudes. A total of 153 species, 2129 stems (709 stems ·ha -1 ) of ≥10 cm girth were enumerated. Species richness and diversity pattern varied along altitud- inal gradient and increased with the altitude. Species richness varied from 52 to 110 species·ha -1 and stand density from 639 to 836 stems·ha -1 with average basal area of 34.39 m 2 ·ha -1 . Shannon-Wiener index (H’) ranged from 4.55 to 5.17. Low altitude (i.e., Site 1) is dominated by Xylia xylocarpa (59.22) and Lagerstroemia parviflora (23.90), medium altitude (i.e., Site 2) by Xylia xylocarpa (45.50) Bursera serrata (17.29), and high altitude (i.e., Site 3) has Schleichera oleosa (28.25) Pterocarpus marsu- pium (26.55) as predominant species. Taxonomically, Rubiaceae (12 species), Fabaceae (12), Euphorbiaceae (11), Rutaceae (7) and Lauraceae (7) were dominant families. Density-wise, Fabaceae, Combretaceae, Euphorbiaceae, Anacardiaceae and Myrtaceae were abundant. Thus, conservation assessment based on altitudinal regimes and the information on species structure and function can provide baseline information for monitoring and sustaining the biodiversity.     

Variation in needle longevity of Pinus tabulaeformis forests at different geographic scales

Needle longevity of conifer species is known to increase with latitude, but little is known about intraspecific variation and associated factors within a location. Chinese pine (Pinus tabulaeformis Carr.) forests were investigated to identify patterns of needle longevity at seven sites with distinctive climatic conditions along a latitudinal gradient (33-38 degrees N) in Shaanxi province, northwest China. A demographic approach was used to quantify needle longevity as an index of entire foliage population adjusted to needle-age-specific mortality rates. There were significant differences in needle longevity of Chinese pine stands across sites and across sample plots within a site. Individual tree needle longevity ranged from 0.62 to 3.75 years for 276 samples across sites. Needle longevity increased with latitude (R2 = 0.40, P < 0.0001), but decreased with mean January temperature (R2 = 0.63, P < 0.0001). Foliage retention of Chinese pine stands at the regional level was generally associated with climatic variability, indicating that variation in needle longevity was primarily an environmental acclimation to low temperature in winter. Stand characteristics were closely associated with needle longevity at three sites located within the same climatic zone. Needle longevity was positively correlated with tree age (R2 = 0.48, P < 0.0001) and stand density (R2 = 0.26, P = 0.0015) at Huanglong and Huangling, respectively, whereas it was negatively associated with total tree height at Zhidan (R2 = 0.50, P < 0.0001). It is concluded that, at the stand and individual tree level, intraspecific variation in needle longevity is most likely a result of adaptation to patchy microsite environments.     

不同干扰梯度下尼泊尔森林树种多样性和优势种的变化(英文)

中度干扰可以增强多样性,因此干扰常作为一种管理手段。因而,了解森林干扰的频度和强度以及对林分结构、优势度以及森林多样性等的作用是非常重要的。本研究在尼泊尔设立25个1 ha样地,调查了不同干扰程度对以婆罗双树为优势种的5个林地生物多样性和优势度的影响。共记录67个树种,其中41个树种在轻度干扰的森林,10个在重度干扰的森林。林地之间α多样性差异显著。α多样性随干扰梯度线性降低,而优势度则呈线性增加。婆罗双树相对基面积随干扰强度而增加,重度干扰林下该树种重要值是轻度干扰林下的2倍。α多样性随婆罗叔树相对基面积的增加而以3倍的比率降低。在任意一对干扰林中,树种组成相似性均很低(相似性指数57%),说明β多样性较高。结论:婆罗双树林多样性随干扰强度增加而降低,但是优势度增加。建议控制优势种(婆罗双树)种群,来提高多样性,实现多功能利用的森林管理目标。图5表6参32。     

Ecological variations of woody species along an altitudinal gradient in the Qinling Mountains of Central China:area-based versus mass-based expression of leaf traits

Leaf trait-based research has become the preferred method to understand the ecological strategies of plants.However,there is still a debate on whether area-based or mass-based traits provide different insights into environmental adaptations and responses.In this study,seven key leaf traits(maximum net photosynthetic rate,dark respiration rate,nitrogen content,photosynthetic nitrogen use efficiency,leaf mass per area,leaf dry matter contents and leaf area) of 43 woody species were quantified on the basis of both area and mass along an altitudinal gradient(1100-2700 m) in the Qinling Mountains of China.Differences in leaf traits and bivariate correlations between the two expressions were compared.By considering different expressions,the strengths and directions of the responses of leaf traits to the altitudinal gradient were determined.Leaf traits showed large variations;interspecific variations contributed more to total variance than intraspecific variations.Bivariate correlations between photosynthetic traits and structural traits(mass per area,dry matter content,and area) were weaker on a mass basis than those on an area basis.Most traits exhibited quadratic trends along the altitudinal gradient,and these patterns were more noticeable for area-based than mass-based traits.Area-based traits were more sensitive to changes in temperature and precipitation associated with altitude.These results provide evidence that mass-versus area-based traits show different ecological responses to environmental conditions associated with altitude,even if they do not contain very broad spatial scales.Our results also indicate distinction of photosynthetic acclimation among the two expressions along an altitudinal gradient,reflecting trade-offs among leaf structure and physiological traits.     

How to quantify forest management intensity in Central European forests

Existing approaches for the assessment of forest management intensity lack a widely accepted, purely quantitative measure for ranking a set of forest stands along a gradient of management intensity. We have developed a silvicultural management intensity indicator (SMI) which combines three main characteristics of a given stand: tree species, stand age and aboveground, living and dead wooden biomass. Data on these three factors are used as input to represent the risk of stand loss, which is a function of tree species and stand age, and stand density, which is a function of the silvicultural regime, stand age and tree species. Consequently, the indicator consists of a risk component (SMI_r) and a density component (SMI_d). We used SMI to rank traditional management of the main Central European tree species: Norway spruce (Picea abies [Karst.] L.), European beech (Fagus sylvatica L.), Scots pine (Pinus sylvestris L.), and oak (Quercus robur L. and Quercus petraea L.). By analysing SMI over their whole rotation period, we found the following ranking of management intensity: oak<beech<pine?spruce. Additionally, we quantified the SMI of actual research plots of the German Biodiversity exploratories, which represent unmanaged and managed forest stands including conifer forests cultivated outside their natural range. SMI not only successfully separate managed from unmanaged forests, but also reflected the variability of forest management and stand properties across the entire sample and within the different management groups. We suggest using SMI to quantify silvicultual management intensity of stands differing in species composition, age, silvicultural system (even-aged vs. uneven-aged), thinning grade and stages of stand conversion from one stand type into another. Using SMI may facilitate the assessment of the impact of forest management intensity on biodiversity in temperate forests.