华北落叶松引种试验的探究

华北落叶松和同龄的长白落叶松相比照,无论是平均胸径、平均树高还是平均材积,前者都落后于后者,现已形成低质低效林分,没有实用价值。因此,应尽快伐除华北落叶松,按照适地适树的原则,采取人工更新恢复森林。     

西南桦与高阿丁枫混交幼林生长及其混交匹配性分析

通过对普洱江城苦丁茶场及西双版纳普文试验林场西南桦与高阿丁枫不同混交模式的生长量指标进行调查分析,结果表明,(1)10年生前,西南桦的胸径较高阿丁枫速生,林木的平均胸径西南桦大于高阿丁枫;11年生后,林木的平均胸径高阿丁枫大于西南桦;(2)10年生时,普文林场混交林的西南桦和高阿丁枫胸径生长一致(11.7 cm),西南桦树高超出高阿丁枫树高3.0 m。说明混交林中西南桦为早期速生树种;幼林阶段,西南桦和高阿丁枫胸径于不同的时期呈现错峰生长。同时,西南桦和高阿丁枫的地理分布、立地的生态适宜条件和林学特征等分析结果表明这2个树种在适宜的混交模式下属混交匹配的树种。建议采用非均匀密度控制混交,以实现2个树种的良好生长和长期混交。     

GROWTH AND YIELD MODELS FOR DAHURIAN LARCH PLANTATIONS

Growth and yield models were developed for individual tress and stands based on336 temporary plots with 405 stem analysis trees of dahurian larch(Larix gmelinii(Rupr.)Rupr.)plantations throughout Daxing’anling mountains.Several equations were selected using nonlinearregression analysis.Results showed that the Richards equation was the best model for estimatingtree height,stand mean helght and stand dominant height from age; The Power equation was thebest model for prediction tree volume from DBH and tree height; The logarithmic stand volumeequation was good for predicting stand volume from age,mean height,basal area and other standvariables.These models can be used to construct the volume table, the site index table and other for-estry tables for dahurian larch plantations.     

Structure of a Central-European mountain spruce old-growth forest with respect to historical development

This study examines the structural characteristics of the tree layer, dead wood, canopy openings, and regeneration patterns of a spruce old-growth forest in the Bohemian Forest, Czech Republic. An old-growth stand with minor human influence and a stand that was presumably logged about 200 years ago were analyzed and compared, as some forest managers considered the presumable human impact as a reason for salvage logging. Even though the stands differed in tree density, height and DBH structure, it was not possible to conclude whether it was due to management history or the environmental differences. The volume of dead wood also differed between the stands. There was about 142 and 83 m³ ha⁻¹ of dead wood in the old-growth stand and presumably logged stand, respectively. The amount of dead wood found in the old-growth stand was comparable with values reported from spruce old-growth stands across Central Europe. In both stands, many canopy trees were arranged in linear patterns, which was a result of spruce regeneration on nurse logs. This suggests that the origin and development of the stands were characterized by natural processes and during the past 200 years typical old-growth structural characteristics have already evolved.     

古田县马尾松人工林分出材率表的编制

应用古田县近年来伐区调查实际造材数据,以林分平均胸径和平均高为自变量,分别以林分总出材率和规格材出材率为因变量,选择理查德方程建立马尾松人工林分一元和二元材种出材率模型。经拟合结果分析,以林分平均胸径D和平均高H的组合D2H作为自变量,其拟合效果和预估精度要高于只用一个平均胸径或平均高的单因子林分材种出材率模型。并编制了林分一元和二元材种出材率表。     

动态规划对黄杉林的经营规划研究

基于87块黄杉林林分生长数据,采用林分生长竞争指数与Richard生长方程相结合的方法建立林分胸径生长量方程,然后以林分密度与林分胸径作为状态变量,以林分综合价值作为指标函数,建立黄杉林最优经营规划的离散确定性动态规划模型。为解决多目标决策问题,通过设定材积与碳汇的权重,有效解决森林经营中木材生产与增加碳汇储量之间的对立关系。结果表明：通过动态规划方法对林分密度加以控制,可以明显的促进林分综合价值的增长。     

生态型林地清理对杉木生长及物种多样性的影响

研究了采伐迹地采取生态型林地清理方式对杉木生长及物种多样性的影响.结果表明:1～2 a生采取生态型林地清理方式杉木生长小于没采取生态型林地清理方式的对照林分,3 a生基本接近,5 a生采取生态型林地清理方式的大于对照林分.15a生时采取生态型林地清理方式的林分平均胸径、平均树高和单位蓄积分别是对照林分的110.5%、125.9%和143.1%;采取生态型林地清理方式的林分土壤肥力及物种多样性均比对照林分高.     

杨树截冠造林影响林木生长发育的研究

通过对采用截冠和留冠两种类型苗木进行杨树造林后的生长情况调查得知:苗木留冠与截冠对造林成活率没有影响。对林木生长影响较大,留冠苗林分平均树高4.9m,胸径4.8cm,分别比截冠苗木林分平均树高、胸径大1.8m和0.6cm,且留冠苗林相整齐、林木长势良好。     

庞泉沟保护区天然华北落叶松林单木生长过程研究

以关帝山林区的天然华北落叶松为研究对象,在不同立地条件下设置了3块标准样地,选取25株平均标准木进行树干解析,采用Log istic方程和R ichards方程拟合树高和胸径、材积生长过程。结果表明：1）胸径、树高前5 a生长缓慢,5 a后加速生长,而材积在前10 a生长缓慢,10 a后加速生长。2）不同立地条件下华北落叶松胸径、树高、材积总生长量前30 a差别不明显,30 a后立地条件越好,三者的总生长量越大且长势较好,表现出速生丰产的优势。     

日本落叶松原生种源和次生种源对比试验研究

为扩大日本落叶松的遗传变异幅度,改善中国日本落叶松的育种状况,提高育种水平和林业生产力。对落叶松种和种源、原生种源试验林建成后10 a的数据进行比较,结果表明:日本落叶松次生种源的胸径、树高、单株材积分别是原生种源的1.10,1.11,1.23倍;选育出了13个优良种源,为我省及辐射推广地区营造日本落叶松速生丰产林找到了优良种源。     

Growth effect of Manchurian ash in mixed stands

lntroductionThepIantingofFraxiusm8ndShurfoabeganatShangzhi,Kedong,YianandFujincountiesofHei-longjiangProvincein196o'.Ash(hainusmand-shurica)andlarch(LarisgmehnI),AshandKoreanpine(PinuskoraiensiS)mixedstandwereremainednow,whichwereartificial,orformedbyplantingAshatterpIantingpureconiferousforest,orinducedbyestablishingeffectareainnaturalashforest.TherearemanyreferencesonthegrowthofashmixedstandinChina.Butinthepast,thestudyoftherela-tionshipbetWeentheincreasinggrowthofmixedstandwithdiffe…     

内蒙古大青山前坡油松人工林生长特征研究

以内蒙古大青山前坡38 a生、17 a生油松人工林为研究对象,对林分生长特征、部分立地因子特征进行调查分析,研究造林立地因子对人工林生长的影响.结果表明:(1)38 a生油松人工林平均树高、胸径和冠幅分别为7.36 m、9.8 cm和261.1 cm;17 a生油松人工林平均树高、胸径和冠幅分别为2.86 m、8.1 ...     

母岩母质类型与坡位对湿地松林分生长的影响

对板页岩红壤和四纪红壤2种不同母质土壤和3种不同坡位上的湿地松林分进行调查与分析。结果表明:在四纪红壤与板页岩红壤中生长的湿地松林分其生长量差异显著,说明母质对湿地松林分的生长具有显著影响;位于上坡位的湿地松林分在四纪红壤中的生长表现要显著优于板页岩红壤中的,相反,位于下坡位的湿地松林分在板页岩红壤中的生长表现要显著优于四纪红壤中的。不同母质土壤的湿地松林分受坡位影响程度不同,但生长指标都一致呈现出下坡位>中坡位>上坡位的趋势;四纪红壤中,下坡位林分平均胸径分别高出上坡位、中坡位林分的10.6%和4.0%;板页岩红壤中,下坡位林分平均胸径高出上坡位林分的45.6%,高出中坡位林分的22.2%,差异达极显著(P<0.01)。总体上在不同母质土壤中生长的湿地松林分生长量差异显著,并且板页岩红壤湿地松林分坡位间生长量差异大,四纪红壤湿地松林分坡位间生长量差异较小。     

Simplified inference about dominance in forest stands

In a series of papers, Binkley and coauthors suggested dominance curves as a framework for understanding growth dominance and resource use efficiency in forest stands. Constructing a dominance curve requires three major supporting components: an appropriate allometric equation for biomass, sufficient data to characterize the size distribution of trees in the stand, and data on growth from a sufficient number of trees to characterize the relationship between tree size and growth across the entire size distribution. These components are not always available. Here, I propose a simplified approach to inference that can be used to diagnoze positive, neutral, and reverse dominance when the conditions for constructing a full dominance curve cannot be met. I illustrate the approach with published data from an old-growth kauri (Agathis australis) stand, which shows clear evidence of reverse dominance.     

桂西南马尾松人工林生长对不同强度采伐的动态响应

[目的]研究不同强度采伐下马尾松的生长动态,筛选适宜的采伐强度,为马尾松人工林近自然经营提供技术支撑。[方法]2007年10月在14年生马尾松人工林(保存密度1 100株·hm~(-2))内进行采伐试验,设置4个采伐强度,即保留密度分别为225、300、375、450株·hm~(-2),以不采伐为对照;其后,自2008年开始连续8 a,每2 a测定1次马尾松的胸径、树高、枝下高和冠面积等生长指标,并计算单株材积和林分蓄积量,应用方差分析和Duncan多重比较分析生长指标对不同采伐强度的动态响应。[结果]表明:采伐强度显著影响林分生长,其中,林分平均胸径、单株材积、冠面积的年均增长量随保留密度增大而减小,但均显著高于对照(P0.05)。采伐后第1 3年,马尾松冠面积增长量显著高于采伐后期,胸径则在采伐后第3 5年最高,而不同采伐强度对林分树高生长影响不明显。保留密度显著影响林分枝下高和蓄积量的动态变化,其年均增长量随密度增大而递增。5个处理间林分蓄积年均增长量的差异随林龄的增大而逐渐缩小。[结论]马尾松人工林生长对不同强度采伐的动态响应以树冠最敏感,冠面积首先陡然增大,进而引起胸径的快速生长。树高和枝下高在采伐后年均增量变化相对平稳。4个采伐强度均显著促进单株材积生长,而仅保留密度为225株·hm~(-2)的采伐对林分蓄积增长量影响显著。综合比较林分的单株材积和林分蓄积连年增长量,建议在桂西南15年生马尾松人工林近自然经营中宜选择300株·hm~(-2)的保留密度进行采伐。     

马尾松天然次生林间伐效应研究

于平均年龄为23年生、地位指数为14和12的2种立地的马尾松天然次生林中,分别设置固定标准样地,并分别设计5个和6个密度水平,对其抚育间伐4年后的间伐效应进行研究。结果表明:不同地位指数的林分,其间伐前或间伐后立木径级分布均呈现正态分布的规律;间伐前林分分化强烈,立木径级大小悬殊;间伐后林分最小株距和平均株距较接近,大径级林木比例提高;间伐4年后平均径级左右的立木比例明显增加。间伐4年后,当14地位指数林分的密度大于1 500株/hm2,12地位指数林分的密度大于1 950株/hm2时,其胸径离散度较间伐当年间伐后的反而明显增大;平均胸径和单株材积的增长均随保留密度的加大而减小,但单位面积蓄积量增长则在其适宜密度时最大;不同保留密度各处理间平均胸径、单株材积以及单位面积材积增长的差异均达极显著,但树高和比重增长的差异均不显著;间伐各处理的平均胸径、单株材积以及单位面积材积增长均大于对照;14地位指数马尾松林以保留密度为1 500/hm2处理的单位面积材积增长最大,增长30.29%;12地位指数马尾松林以保留密度为1 950/hm2处理的单位面积材积增长最大,增长24.38%。     

Belowground carbon pools and processes in different age stands of Douglas-fir

Forest floor material and soil organic matter may act as both a source and a sink in global CO2 cycles. Thus, the ecosystem processes controlling these pools are central to understanding the transfers of carbon (C) between the atmosphere and terrestrial systems. To examine these ecosystem processes, the effect of stand age on temporal carbon source-sink relationships was examined in 20-year-old, 40-year-old and old-growth stands of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) in the Cascade Mountains of south-central Washington State. Belowground C and nitrogen (N) storage and soil respiration were measured. In addition, nylon mesh bags containing homogenized soils from each site were buried at the respective sites to quantify root ingrowth and potential C sequestration and loss. The sites supporting the 20- and 40-year-old stands had soil C stores reflecting the C contributions from logging residue, coarse woody debris and stumps left after harvest. Because the N-fixer red alder (Alnus rubra Bong.) comprised 33% of the 40-year-old stand, this site had significantly greater concentrations and pools of N in the forest floor than sites without red alder. This N-rich site had consistently lower soil CO2 efflux rates during the growing season than the sites supporting the 20-year-old and old-growth stands. Estimated annual soil C efflux was 1367, 883 and 1194 g m-2 for the sites supporting the 20-, 40- and old-growth stands, respectively. These values are higher than previously reported values. Root ingrowth was significantly less in the 40-year-old stand than in the 20-year-old stand, and both young stands showed markedly less fine root growth than the old-growth stand. At the sites supporting the young stands, C and N were lost from the soil bags, whereas there was an increase in C and N in the soil bags at the site supporting the old-growth stand. The fine root growth and soil respiration data support the hypothesis that belowground C allocation decreases with increasing fertility. Quantification of the source-sink relationship of soil C at the three stands based on litterfall, relative root ingrowth and soil respiration measurements was compromised because of significant CO2 flux from decaying organic matter in the young stands.     

朝阳市主要树种组林分平均胸径生长率模型研究

采用超总体理论编制朝阳市油松、刺槐、杨柳、速生杨4个树种组林分平均胸径生长率通用模型,以2005年森林资源二类调查资料为原始数据,涵盖全市所有地区不同地理位置和不同立地条件的生长水平.建立4种模拟方程,通过拟合与优化及结果精度的检验,选择出各树种组的平均胸径生长率模型.     

延庆县森林资源时空动态分析与评价

以北京市延庆县为研究对象,以1999年和2004年森林资源调查数据为基础,以地理信息系统为技术支持,分析和评价了5年间该场森林资源的数量、种类及其结构在时间和空间上的动态变化。结果表明：研究区域林地面积比例由71.39%上升至75.38%,增长了4%,在林地内部,有林地面积增长较明显,增加了约14%。总蓄积量增长了43.6万m^3,达158.24万m^3,增长了38.1%。延庆县全境以栎类林为代表的次生的天然林占主体地位,蓄积也占绝对优势。受人工造林的影响,导致整体平均胸径和平均高减少,也使得侧柏、落叶松、油松等树种分布扩大。全县林分五个林龄组的面积构成呈倒J型分布。     

北京八达岭油松人工林结构分析

用传统林分结构因子配合混交度、大小比、角尺度3参数来分析北京八达岭林场油松人工林空间结构特征.结果表明:该林分的树种组成式为8油松1槲树1山梨 暴马丁香,林分密度为1 325 株/hm2.林分的平均角尺度为0.478,林分立木空间分布格局为随机分布.平均混交度为0.433,不同树种间呈现中度混交,种间隔离程度较小.林分平均胸径大小比为0.389,平均树高大小比为0.464,说明处于优势地位的株数较多,林分分化明显,且林分的发展空间还很大.胸径大小比数和树高大小比数在反映各树种参照树与相邻木之间的生长优势方面具有较强的一致性.