共查询到20条相似文献，搜索用时 31 毫秒
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João P.F. Carvalho 《Forest Ecology and Management》2011,262(10):1928-1937
Stand composition and structure of natural mixed-oak stands of common-oak (Quercus robur L.) and pyrenean-oak (Quercus pyrenaica Willd.) were studied. Diverse compositional and structural elements in early and late successional stand stages were analysed. The study was conducted in north and central Portugal where different natural mixed oak forests types are located. The following mixed-oak forest types involving common-oak and pyrenean-oak were studied: common-oak & other hardwoods; common-oak & cork-oak (Quercus suber L.); ash (Fraxinus angustifolia Vahl) & pyrenean-oak; and pyrenean-oak & madrone (Arbutus unedo L.). Measurements were made in early and late successional stand stages on the different mixed oak forest types. Different stand characteristics and indices were used to describe and compare stand structure and composition. The study showed changes in species diversity and stand structure. Most tree species in mature stands are present in early stages but with higher abundance. Shannon diversity index may change between 0.798 and 1.915. Significant differences on species diversity and abundance were found depending on the forest type and successional stage. Mature mixed-oak forests have high species diversity with an abundance of small to medium tree size species. Species distribution and diameter differentiation indices range from 0.30 to 0.70 and 0.52 to 0.82, respectively, revealing significant structural complexity. The average number of standing and downed dead trees was 265 and 83 trees ha−1 for early and late stage, respectively, with 6.9 and 65.4 m3 ha−1. Higher values of stand diversity index were 41 and 53 in more complex and developed forests. Later stand stages have complex structure, with a wider range of tree diameter distribution and higher degree of irregularity. 相似文献
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Bāders Endijs Jõgiste Kalev Elferts Didzis Vodde Floortje Kiviste Andres Luguza Solveiga Jansons Āris 《European Journal of Forest Research》2021,140(4):819-833
The anticipated increase in extreme disturbance events due to climate change is likely to expose Norway spruce (Picea abies (L.) Karst.) dominated forests in northern Europe to new conditions. Empirical data on the resilience of such natural (unmanaged) forests to disturbance and the long-term patterns of regeneration in its aftermath are currently scarce. We performed a quantitative assessment of natural forest stands in north–western Latvia to identify and characterise the patterns of stand structure 44 years after a stand-replacing disturbance and investigated the effects of legacies on regeneration. The spatial distribution of tree species and their dimensions were assessed in 71 circular sample plots (500 m2 each) in natural forest areas, where Norway spruce dominated prior to the windthrow and salvage logging was not carried out. Spatial indices (species mingling index, size differentiation index, and aggregation index) were used to characterise stand structure and diversity. The different initial states (age and coverage of surviving trees) of stands affected eventual tree species dominance, size differentiation, degree of mingling and aggregation. Our results demonstrate a close relationship between disturbance legacies and spatial indices. The pre-storm understory and canopy survivors decreased species mingling, whereas survivors increased size differentiation. The size differentiation increased also with a higher degree of species mingling. Leaving differential post-storm legacies untouched promotes a higher structural and species diversity and therefore supports the management approach of preserving canopy survivors.
相似文献4.
The development of mixed broadleaved-Korean pine (Pinus koraiensis Sieb. et Zucc.) forests in the Changbaishan Biosphere Reserve, located on the border with North Korea, was simulated using the gap model KOPIDE. Forest succession was simulated under three initial conditions from: (1) bare ground after clearcutting; (2) secondary forest; (3) old-growth forest. The simulations from the different initial conditions converged and support earlier successional theory that Korean pine is the climax species on the highlands of northeast China even under disturbed conditions. In addition to clear-cutting, the resilience of the forest to different levels of other human impacts, pine seed harvesting and selective cutting, was examined. These results further demonstrate that these forests possess a relatively stable structure characterized by the dominance of Korean pine. However, the model showed successional processes of the forest to be susceptible to high levels of pine seed harvesting. To predict forest dynamics at landscape scales, KOPIDE was linked with a Geographic Information System containing site and stand data sets. Running this model to simulate a forested area initially comprising several successional stages suggests that, in the absence of disturbance, Korean pine is likely to become increasingly dominant on the area over the next century. 相似文献
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不同强度间伐对长白山天然林林下植物多样性的影响 总被引：1，自引：0，他引：1
对吉林森工集团松江河林业局辖区内的阔叶红松林、杂木林和杨桦林采取30%～40%（T1）、20%（T2）株数强度的均匀间伐处理,以不间伐处理为对照（CK）,对间伐2 a后林下植物木本、草本植物进行调查,采用Simpson、Shannon-Wiener多样性指数和Pielou均匀度指数进行植物多样性分析,探讨不同强度间伐对3个林型林下植物多样性的影响。研究结果表明：T1间伐后3个林型的物种丰富度均有增加（杂木林木本植物例外）,T2间伐后杨桦林木本植物丰富度降低,草本植物丰富度增加。两种间伐处理均增加阔叶红松林木本植物多样性,T1处理尤为明显。T1处理增加杂木林和杨桦林木本植物多样性,而T2间伐处理有较弱的降低作用。两种间伐处理均降低阔叶红松林和杂木林草本植物多样性,与强度无明显关系。随着间伐强度的增加杨桦林草本植物多样性增大。在长白山天然林中,较大间伐强度T1（30%～40%）能够有效提高植物多样性。 相似文献
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《Scandinavian Journal of Forest Research》2012,27(6):538-547
The state of mixed forests of maritime pine ( Pinus pinaster Ait.) and broadleaved species in the coastal region of Galicia (north-western Spain) was described using data from 213 circular sample plots selected among the available 4700 plots of the Spanish National Inventory. A matrix model was developed for this forest type to obtain information about the productivity and potential for sustainable management. The broadleaved species had a diameter distribution close to the inverted J-shape typical of the uneven-aged forests but for maritime pine there were many medium-sized trees and a lack of trees in the first diameter class of 15 cm. The matrix growth model was used to predict the development of mixed forests for three different management options: no harvesting in a well-stocked stand, a regime with a 5 yr harvest cycle and a residual basal area of 15 m 2 ha -1 in a well-stocked stand, and a rehabilitation management applied to an understocked stand. The results showed the possibility of applying uneven-aged silvicultural systems to these forests, leading to the production of high-value timber and to the maintenance of continuous cover and a biodiverse forest. 相似文献
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大兴安岭天然白桦林群落结构特征及其物种多样性 总被引：1，自引：0，他引：1
基于2011年大兴安岭地区的样地调查数据,分别用大小比数、混交度和角尺度来衡量林分空间结构特征;用Simpson生态优势度指数、Margalef丰富度指数、Shannon多样性指数以及Pielou均匀度指数来衡量群落的物种多样性水平。研究结果表明：随着白桦优势度的提高,群落的物种多样性、丰富度和均匀度指数均显著下降;从林分的空间结构特征来看,混交林的水平分布格局呈随机分布,林分的混交程度高,林木的生长水平整体处于中庸状态;各项指标均表明,白桦混交林具有较高的物种多样性和群落的稳定性,对白桦林向松桦混交林过渡的群落演替趋势研究有重要意义。 相似文献
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Shengdong Liu Shirui Dong Ruitong Liu Qingfan Meng Yan Li Hongrui Zhao Yinghua Jin 《林业研究》2022,33(1):333-342
Carabid beetles,predatory insects,are abundant in forests and sensitive to environmental changes.The dis-tribution patterns and diversity of carabid beetles in several natural forests were studied to provide a basis for evaluating the importance of a forest in the protection of carabid beetle diversity.Carabids were captured by pitfall traps during their seasonal activity from 2012 to 2013 in a poplar-birch forest,ash-walnut forest and broad-leaved Korean pine forest.A total of 5252 individuals,representing 21 species,were col-lected.Carabid abundance was highest in the broad-leaved Korean pine forest and lowest in the ash-walnut forest.Carabus billbergi Mannerheim and Pterostichus pertinax(Tschitscherine) were the dominant beetle species in each stand.Carabus canaliculatus Adams was dominant in the poplar-birch and ash-walnut forests,and Leistus niger Gebler was dominant in the ash-walnut forest.The carabids were affected differently by stand factors.C.billbergi and P.per-tinax was positively correlated with mean DBH.C.cana-liculatus and L.niger were not positively correlated with any stand factors.The broad-leaved Korean pine forest with greater age,large DBH and thick leaf litter fostered a high diversity of carabid species.The main yearly activity period for most carabids was during July.Different carabid species responded differently to seasonality,and the activity period of several species was relatively late (August) in the year. 相似文献
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在黑河市平山林场选取环境条件(如坡度、坡向、郁闭度等)相似的阔叶混交林、落叶松阔叶林、红松阔叶林3种森林群落类型样地灌木进行分析的结果表明,红松阔叶林的Gleason指数、Shannon-Wiener指数、Simpson指数都较大,其物种丰富度和多样性均较高;毛榛子为各林分类型下灌木层的主要物种。 相似文献
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Ge Jianping 《林业研究》1994,5(4):1-5
The thesis for the Doctorate consist of two parts. The first is to study on structure, dynamics and tree growth of natural
Korean pine forest. The second is to research for tree architecture, growth and stand structure of artificial Korean pine
(Pinus koraiensis) forests.The thesis compares the stand structure, process of regeneration, and various tree growth patterns between natural
forests and artificial forests. Its purpose is to give a basis for forest management and silviculture. The study was carried
out in Liangshui Experimental Forest Farm, which is located in the southern Xiaoxing’an Mountains. 相似文献
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THEMAINCoNTENToNTHENATURALFORESTAgeStTucture,SpatialPattern,andDynamicsofKoreanPineForestSpa-halpatternoftrees,basalstemincrementandheightwereexaminedina5.ohm2mixeddeciduous/Pinuskoraiensisfor-est.ConcIusionsareasfollowingtAgestructureAgedeterminationsonthestudyplotshowthatKoreanpineisalonglivedtreespeciesandunevenagedpopuIation.ThegeneraIecoIogicalIongevi-tyisabout3OO-4oOyear-o1d.TheoverstoryKoreanpinetreesincludeawiderangeofage,themaximumageofKoreanpinetreeonthestudyp1ot… 相似文献
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太行山低质低效林改造后的水文效益 总被引：3，自引：0，他引：3
在示范林内选取了几种有代表性的森林植被类型,即分别代表太行山的主要乡土树种油松、辽东栎,及经改造形成的主要混交林类型松栎混交林和油落桦混交林。用标准木法和样方法分别测定了林分单位面积各森林植被层的生物量及总生物量,用浸水法测定了各森林植被层的日最大持水量。观测了油松示范林林冠截留降雨能力。 相似文献
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长白山北坡椴树阔叶红松林群落主要树种的年龄结构研究 总被引：14，自引：0，他引：14
通过对长白山林区椴树阔叶红松林伐根的大量调查 ,认为红松种群是由不同年龄阶段的群团状斑块组成 ,以多世代群居 ,优势世代之间没有一定的严格间隔期 ,在年龄结构图上往往出现两个或两个以上高峰。阔叶树在天然红松林中的分布呈群团状或散生 ,阔叶树的年龄也为异龄性 ,也为多世代共居。红松与阔叶树之间存在明显的动态消长关系 ,同龄伴生 ,异龄混生 ,形成复层异龄的针阔混交林 ,年龄结构与年生长关系的数学模型表明年生长量与年龄有正相关趋势 ,但林木年龄达到老龄时 ,生长有所减缓 相似文献
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Large scale harvest of Korean pine(Pinus koraiensis) seeds as a food product in the mixed Korean pine-hardwood forest of northeastern China poses a serious threat to the sustainability and restoration of this endangered regional ecosystem.Seed collection over past decades greatly reduced the seed bank and subsequent seedling and sapling recruitment,and impacting a wide array of granivorous animals that rely on the pine seeds.We surveyed Korean pine seeds,including solid seeds(SS),insect consumed seeds(ICS) and other(animal) consumed(OCS) kernels,of the seed bank(forest floor and the top 10 cm of mineral soil),the seedlings and saplings from 1 m 2 sample plots in five forest types in Liangshui Nature Reserve(LNR) of the southern Xiao Xing’an Mountains in northeastern China to provide accurate information for assessing the Korean pine regeneration potential.The average number of pine seeds in the seed bank were 11.2 seeds/m 2,9.1 seeds/m 2,4.6 seeds/m 2,1.1 seeds/m 2,and 0.2 seeds/m 2 in Korean pine-basswood forest,mixed Korean pine-hardwood forest,mixed conifer-hardwood forest,white birch forests,and oak forests,respectively.In the first three forest types,percentages of SS(potentially viable seeds) were 11.2%,3.5% and 27.8%,respectively.The percentages of ICS(not viable seeds) were consistent at around 35%.The higher but variable percentages of OCS(not viable seeds) indicated high seed predation in these forests.Compared with other studies,we recorded higher percentages of seed damage,probably due to our survey approach and the increased depth of seed bank sampled in our study.Depletion of pine seeds in the seed bank greatly reduced seedling and sapling recruitment.Densities of pine seedlings varied from about 180 trees/ha in the mixed Korean pine-hardwood forest to about 5,400 trees/ha in the mixed conifer-hardwood forests and showed a high degree of spatial variation.Saplings were rare in the mixed Korean pine-hardwood forest,but ranged in the thousands in other forests.Large scale pine seed harvest has seriously threatened the sustainability of the mixed Korean pine-hardwood forest ecosystem.Scaling down the seed harvest or supplemental planting of pine saplings are urgently needed to maintain the health of the existing Korean pine forests and to restore this endangered ecosystem. 相似文献
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阔叶红松林主要树种生长的水热指数和最优生长过程的模拟研究 总被引：3，自引：0，他引：3
以阔叶红松林8个主要组成树种为研究对象,根据水分和热量是决定植物地理分布的主要因素的原理,应用干燥度和≥10℃的年积温建立了树木生长水热指数;设在最佳环境条件下树木的生长与叶量成正比,与本身大小成反比,推导出树木最优生长模型。然后,应用该水热指数和生长模型模拟了不同水热条件下树木的最优生长过程,揭示了不同树种、或同一树种在不同水热条件下的生长特征。这些研究结果可用于划分树种地理分布区质量等级和评价林分的生长。 相似文献
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IntroductionAgestructureoftrees,whichreflcctsrcge11eratio11processandvelocity,meansquantityoftreesdividingbyage.Broad-leavedKoreanpineforestwastl1etypicalzol1alvegetationofChangbaiMountaininNortheastO1ina,anditwastheprimarygymnospermconununitysurvivedaftertheQuatemaryGlacierPeriod.Alotofcommunityinf`)r-mationaccumulatCdinthestr-uctllreofforeststandsa11dgrowingprocessofindividualtrees.So,athoroughstUdyonagestructureanditsdistributiol1ofbroad-leavedKore-anpine.forestwouldprovidetl1eoretical… 相似文献
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指出了龙里林场现有国家储备林中以马尾松人工林为主,树种结构单纯、层次结构简单、生态效益差、生态系统脆弱,容易发生雪压、风倒、火灾,松毛虫危害严重。为了改善林场马尾松人工林的健康状况,提高物种多样性和生态稳定性,优化林分的树种、水平、垂直结构,进一步提高林分质量,模仿马尾松自然演替规律,通过择伐,在林下补植了乡土珍贵树种,以把马尾松人工林尽可能地改造为接近自然状态的异龄针阔混交林,结果表明:近自然改造具有如下优点:①确保了持续的主林层郁闭,实现了森林的永续利用。②将培育珍贵树种与马尾松大径材有机结合起来,兼顾了森林的经济、生态、社会效益。③有利于提高林分质量,保证了森林的健康可持续发展。 相似文献
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There arc eight species and four varieties of oak in northeast China. This paper reports and describes the distribution and
phylocoenogenesis of the Korean pine-broadleaved mixed forest and the mongolian oak formation. The close relationship between
the flora of Ussuli—Amur region and Japan is discussed. Analyses of heat and energy balance, and biomass of mongolian oak
forests arc provided. Many measurements indicate that, in a nonclosed stand, the wood production of a stand is positively
correlated with leaf area index (LAI). 相似文献