共查询到20条相似文献，搜索用时 268 毫秒
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本文在对享有“蜀南竹海”之称的长宁县楠竹林分进行全面调查的基础上，运用多元统计分析方法，把与楠竹林分生长有密切相关的立地因子、林分在子和生产力重要值（ＳＩｗ），新竹（１－３度）株数、秆材重量等能全面反映楠竹生长的生产力指标进行了数量化分析，借助电子计算机进行方程参数求解，编制出了楠竹林分立地、林分结构因子三个生产力指标数量化查定表。同时，对楠竹林分立地质量进行了了数量评价，用主导因子逐级控制综合分 相似文献
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对子午岭林区影响油松人工林生长的主要立地因子进行了调查研究和分析，认为在该区影响油松生长的主导因子是坡向，海拔次之。运用数量化理论（Ⅰ）编制了“子午岭油松立地质量得分表”，并在此基础上编制了“油松立地质量评价表”，把以往对宜林地的定性描述提高到了定量评价，使造林水平上了一个新台阶。 相似文献
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根据浙江２９０块马尾松人工林样地的８个立地因子和９个交互作用因子数据，运用逐步回归、交互逐步回归及数量化理论Ⅰ三种方法，剔除无效变量，分别对武夷山北坡产区、天目山产区及浙东、浙西丘陵产区所调查的立地因子（海拔高、土层厚度、黑土层厚度、坡位、坡向等），进行统计分析与检验。从剩余标准差、方差比、复相关和偏相关等检验结果看，以数量化法计算结果最精确，交互逐步回归法次之。本文还根据入选因子类目的相关距阵，用数量化理论Ⅰ法计算出立地质量得分值，并编出三个产区的数量化地位指数表。 相似文献
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红松大径材林立地质量评价 总被引：1，自引：0，他引：1
《林业科技》2021,46(2)
对黑龙江省东京城林业局的红松大径材人工林进行林分调查和立地因子调查,运用数量化理论Ⅰ对样地进行数量化分析,选择坡向、海拔高度、坡位作为主导因子,将东京城地区红松大径材林划分为4个立地类型组和17个立地类型。建立红松优势高与立地因子的关系模型,对东京城地区红松大径材林进行立地质量评价,结果显示,东京城地区50%的立地质量评价为优,50%的立地质量评价为良,无差评。 相似文献
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为了对榆林沙区樟子松人工林的造林培育及可持续经营提供参考依据。本研究在榆林市榆阳区设置了38块20 m×20 m的樟子松人工林样地,调查了不同林龄樟子松的胸径、树高等生长指标,应用数量化理论Ⅰ预测模型建立樟子松人工林优势木平均树高与立地因子之间的多元回归方程并确定立地评价等级,对樟子松人工林的立地质量进行了数量化评价。结果表明：（1）榆林沙区樟子松人工林随着林龄的增长,樟子松人工林平均胸径、树高均会有显著增长,且在第10～20年增长速度最快。（2）以坡向、海拔和坡位这三个主导因子将樟子松人工林划分为12个立地类型区,进行立地分类结果评价。通过对调查样地进行立地评价,可以看出调查样地中75%的樟子松人工林立地评价等级在中级以上,表明榆林地区的樟子松种植区域立地条件较好,适合樟子松种植。预测方程经过检验达到要求,说明利用数量化理论Ⅰ可以对樟子松人工林进行立地质量评价和生长趋势预测。 相似文献
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油料树种光皮树人工林立地质量评价 总被引：2，自引：0，他引：2
在湖南省不同适生区范围内的光皮树生产基地,按不同生长类型、不同立地条件林分设置临时标准样地30块,在每块标准样地内进行每木检尺,测定胸径、高度、枝下高、冠幅等林分结构因子的数量特征,并调查和收集林下植被、立地因子(海拔、坡向、坡度、坡位)、气象因素、经营水平等环境特征。采用样地调查法进行林分结构调查、标准木和林分优势木解析法测定树干生长过程和生物量。用各种立地条件下的大量树干解析材料,拟合树高与年龄的回归方程式作为导向曲线,再利用树高调整法编制光皮树的地位指数表以及地位指数曲线簇。在综合分析影响光皮树生长发育的环境因子的基础上,选择了5个立地因子,运用数量化理论I方法,构建立地质量评价数量化模型,进行光皮树的立地质量评价。 相似文献
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A forest biomass yield table based on an empirical model 总被引：1，自引：0，他引：1
Tomohiro Nishizono Toshio Iehara Hirofumi Kuboyama Miki Fukuda 《Journal of Forest Research》2005,10(3):211-220
We report an empirical model for estimating unutilized wood biomass, and its application to Cryptomeria japonica D. Don and Larix kaempferi in Tohno City, Iwate Prefecture, northeast Japan. Outputs from the model are the quantity of unutilized wood biomass and merchantable volume produced by timber harvest. The unutilized wood biomass is divided into stumps, tops, branches, foliages, small trees, and unutilized stems due to their defects. Inputs to the model are mean diameter at breast height (DBH), mean tree height, trees per unit area, and timber utilization standards. DBH distribution, DBH–height curve, stem form, bark thickness, and relationship of stem biomass to foliage and branch biomass could be described by the proposed model, indicating its validity. The proposed model enables us to develop the forest biomass yield tables modified from the existing stem volume yield tables. The developed forest biomass yield tables indicated that the unutilized wood biomass due to defects accounted for the largest part of the whole unutilized wood biomass, and that the ratio of unutilized parts in stem volume to total stem volume could vary with stand age and site productivity class. Based on a comparison of the developed forest biomass yield tables with those reported previously, we concluded that the proposed model-based forest biomass yield table would be useful for estimating the quantity of unutilized wood biomass. 相似文献
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江西千烟洲几种灌木生物量模型的研究 总被引：7，自引：0，他引：7
研究以中国科学院江西省千烟洲红壤丘陵综合开发试验站(以下简称千烟洲站)人工森林中灌木层的4种常见灌木为对象,采用SPSS、EXCEL等统计软件对数据进行回归分析,建立灌木各营养器官生物量及总生物量与各测树因子的回归模型,所得的各样本总生物量回归方程为:四川红淡比:Y=0.677X0.6293,山矾:Y=11.672+0.0201X+(2E-05)X2,格药柃:Y=597-48.86X+1.365X2,钩藤:Y=208.2-46.47X+2.91X2。通过对模型的精度检验,其结果表明:本实验建立的灌木各营养器官生物量同各测树单因子及复合因子之间的回归方程相关性好,可用于推算灌木生物量。 相似文献
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国内外灌木生物量模型研究综述 总被引：4，自引：0，他引：4
灌木林是自然界中广泛存在的一种陆地生态系统类型, 是森林资源的重要组成部分。文中对国内外灌木生物量模型的研究现状进行了综述, 从数据采集、建模方法和模型评价3个方面系统总结了灌木生物量模型研建的技术要点。数据采集主要包括样本单元数的确定、测定因子的选定和样本数据采集3部分, 其中样本数据采集又包括野外鲜质量测定和实验室干质量测定2部分。建模方法的重点是确定灌木生物量模型的结构和选择参数估计方法, 而模型评价的核心是选定合适的评价指标。文中从开展国家级森林植被生物量监测的角度提出建立灌木生物量模型的有关建议, 即首先要确定合理的建模样本单元数, 再选择合适的灌木生物量建模技术方法, 还要重视对所建模型的评价, 给出模型的预估精度指标。 相似文献
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华北落叶松林生物量与生物多样性关系研究 总被引：2，自引：0，他引：2
以河北省木兰林管局境内华北落叶松人工林为研究对象,在采用标准地调查方法取得主要林分因子调查数据的基础上,利用ForStat统计软件,建立了华北落叶松人工林生物多样性与生物量关系模型。结果表明:未成林造林地,灌木与草本生物量与生物多样性呈正相关关系;幼龄林林木分化尚不明显,生物量与林分密度呈线性关系,符合y=0.005 1x+4.334 3,R2=0.842 7;幼龄林物种丰富度在25左右时生物量达到最大;近熟林生物量与生物多样性呈正相关。 相似文献
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以孟家岗林场二类清查数据为基础,对1371个小班的11项指标进行主成分分析,并采用系统聚类法对小班进行分类,进而利用支持向量回归算法分别进行生物量模型训练.结果表明：7个主成分指标可反映87.995％的生物量信息;1371个小班可分为5类,各类训练模型的预测精度均在89％以上,且均以v-SVR模型为最优.在得到的5类生物量训练模型基础上估算林场森林乔木层生物量,无需分起源、树种、立地类型,能够在保证生物量估算精度的同时,大大减少工作量,可为区域生物量的估算提供一种新的方法. 相似文献
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Quantitative information of tree biomass is useful for management planning and monitoring of the changes in carbon stock in both forest and agroforestry systems. An estimate of carbon stored in these systems can be useful for developing climate change mitigation strategies. A precise estimate of forest biomass is also important for other issues ranging from industrial forestry practices to scientific purposes. The individual tree-based biomass models serve as fundamental tools for precise estimates of carbon stock of species of interest in forest and agroforestry systems. We developed individual tree aboveground biomass models for Castanopsis indica using thirty-six destructively sampled tree data covering a wide range of tree size, site quality, growth stage, stand density, and topographic characteristics. We used diameter at breast height (DBH) as a main predictor and height-to-DBH ratio (a measure of tree slenderness) and wood density (a measure of stiffness and cohesiveness of wood fibres) as covariate predictors in modelling. We, hereafter, termed the biomass models with former two predictors as first category models (density independent models) and the models with all three predictors as second category models (density dependent models). Among various functions evaluated, a simple power function of the form \(y_{i} = b_{1} x_{i}^{{b_{2} }}\), in each category, showed the best fits to our data. This formulation, in each category, described most of the biomass variations (\(R_{adj}^{2}\) > 0.98 and RMSE < 72.2) with no significant trend in the residuals. Since both density dependent and density independent models exhibit almost similar fit statistics and graphical features, one of them can be applied for desired accuracy, depending on the access of the input information required by the model. Our biomass models are site-specific, and their applications should therefore be limited to the growth stage, stand density, site quality, stand condition, and species distribution similar to those that formed the basis of this study. Further research is recommended to validate and verify our model using a larger dataset with a wider range of values for site quality, climatic and topographic characteristics, stand density, growth stage, and species distribution across Nepal. 相似文献
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以被研究区（郧县）林地指示树种（马尾松）为目的树种，以海拔、坡度等８个因子为建模自变量，编制了数量化立地指数表和立地类型表，为林地经营提供依据。将此表用于郧县长防林建设总体规划，取得了较好的效果。 相似文献
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[目的]研究桂西南岩溶区不同恢复模式群落的生物量及其林下植物多样性的特点,为该区域的生物多样性保护、生态功能恢复效果评价积累基础数据。[方法]以桂西南岩溶区4种不同恢复模式为研究对象,采用样方法对林下植物多样性进行研究;采用收获法研究灌木层与草本层的地上、地下生物量及凋落物层现存量;采用异速生长模型来估算乔木层的地上生物量,并参考IPCC根茎比来量化乔木的地下生物量。[结果]表明:共调查记录林下植物85种,隶属于46科,81属,其中,灌木植物25科,46属,50种;草本植物21科,35属,35种;不同恢复模式群落生物量的变化趋势为自然恢复林(166.66 t·hm-2)任豆林(48.61 t·hm-2)吊丝竹林(36.54 t·hm-2)灌草坡(0.96 t·hm-2)。[结论]不同恢复模式灌木层物种丰富度差异不显著,最高的为灌草坡(16种),其次为任豆林(15种),最低为自然恢复林(12种);草本层物种丰富度最高的为任豆林(12种),其次为灌草坡(10种),最低为自然恢复林(4种)。自然恢复林乔木不同组分生物量与任豆林、吊丝竹林之间差异显著(P0.05);灌草坡的灌木、草本地上生物量与吊丝竹林、任豆林、自然恢复林之间差异显著(P0.05)。吊丝竹林、任豆林的灌草生物量表现为草本层灌木层,而灌草坡与自然恢复林的灌草生物量则表现为灌木层草本层。 相似文献
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Iciar Alberdi Sonia Condés Ronald E. Mcroberts Susanne Winter 《European Journal of Forest Research》2018,137(3):265-278
Because shrub cover is related to many forest ecosystem functions, it is one of the most relevant variables for describing these communities. Nevertheless, a harmonized indicator of shrub cover for large-scale reporting is lacking. The aims of the study were threefold: to define a shrub indicator that can be used by European countries for harmonized shrub cover estimation using data from their respective national forest inventories (NFIs); to quantify the effects of using different NFI field cover scales; and to establish bridges to facilitate harmonized estimation. Data for shrub species cover from the Third Spanish NFI together with scales for cover assessment from 16 European NFIs were used. The indicator, mean species cover (MSC), was defined for each species and each European forest category. Estimates of MSC calculated using species covers recorded for field plots, with 1% interval widths (MSCobs), were compared with the MSC values that would be obtained for the same data with the different European cover scales (MSCpred). Residuals calculated as differences between MSCobs and MSCpred were analyzed, and a linear mixed model was used as bridging function to adjust predictions and thus further harmonize estimates. Scales with only two or three intervals produced the greatest residuals, while all the other analyzed scales had residuals less than 5%. Most scales, except those most similar to Braun-Blanquet, displayed a tendency to be unreliable for larger covers. The proposed mean species cover indicator provides comparable estimates for shrub communities at large scales. The linear models improved the harmonization of MSC for the scales having two and three intervals. 相似文献