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应用削度方程编制湿地松材积表和出材率表的研究 总被引：1，自引：0，他引：1
在树干形状研究的基础上,利用样木资料建立了一个适合湿地松人工林干形变化规律的可变参数削度方程,据以编制了一元材积表、二元材积表、一元材种出材率表和二元材种出材率表,这些数表经检验误差较小,精度较高,可在林业生产上推广应用。 相似文献
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影响立木材积的因子不仅仅是直径,树高两个因子,干形是单株材积中第三个决定性的因子,但把干形因子引进材积表,在实际测量及预估中既浪费时间,又不经济,所以任何干形的测量在材积预估中都没有实际意义。我们应用的材积表,在编表时每株树都看作具有平均材积——胸径关系中的一定群体中的一株,实际上来自不同地区、不同种源、不同经营管理水平的树木材积——胸径的关系是不一致的,只有当被测树木的干形十分相似于编表所用树木的于形时,这个材积表才能正确地预估材积。鉴于此可以通过模型识别来提高材积预估的准确性。树木干形特征包括了一套相互依存的比率关系。所以模型识别必须在多维分析的基础上进行。 相似文献
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闽东柳杉人工林立木材积表和地位指数表的编制 总被引：5，自引：0，他引：5
本文根据258株柳杉样木资料，编制了一元和二元立木材积表，其模型为V=aDb和V=aDbHc，所编制的材积表经过检验证明适用。根据70株优势木的树于解析材料，用Richards方程编制多态形地位指数表。 相似文献
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利用回归方程建立杉木地径与胸径、树高曲线方程,并结合福建省杉木二元材积公式和出材率表编制了红旗林场杉木地径一元材积表和出材率表,经检验,其精度符合要求,适合红旗林场杉木林分使用． 相似文献
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二元立木材积表编表材料来源于黑龙江省海林林业局标准地的落叶松解析木材料,采用非线性回归模型迭代法拟合材积方程的参数,对方程进行残差分析和参数估计。 相似文献
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基于分位数回归的华北落叶松干形曲线模拟 总被引：1，自引：0，他引：1
干形是反映树干外部形态的重要指标,也是评价干材价值的重要依据,而削度方程是描述树木干形好坏的一个重要定量指标,其对干形模拟的准确性直接决定着树干材积和森林蓄积的估算结果。以河北省塞罕坝机械林场华北落叶松人工林为研究对象,基于4个常见的简单削度方程,模拟了260株样木的干形曲线,采用调整后决定系数(Ra^2)、均方根误差(RMSE)、平均误差(ME)和平均误差绝对值(MAE)评价模型的拟合效果和检验效果,筛选最优的基础模型,并利用分位数回归技术,构建人工华北落叶松干形曲线模型。结果表明,4个简单削度方程中,Kozak方程对华北落叶松干形的拟合效果最好(Ra^2=0.934,RMSE=1.985cm),检验结果也是最优的(ME=0.125cm,MAE=1.212cm)。因此,基于Kozak方程,结合分位数回归技术建立了华北落叶松干形曲线,相较于基础模型,分位数回归模型的拟合优度进一步提高。当分位点设置为0.1时,模型对靠近下部和上部的树干干形拟合效果较好;当分位点设置为0.5时,模型对位于中部的树干干形拟合效果较好;当分位点设置为0.9时,模型对树干基部的拟合效果较好。可见,分位数回归技术使模型具有更强的灵活性。 相似文献
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西江林业局尾巨桉人工林一元材种出材率表编制 总被引：1，自引：0，他引：1
在广东省西江林业局尾巨桉无性系人工林中选择并设置70个标准地,分别进行林分因子调查,同时选择163株样木以2.0 m或2.6 m段材长分径阶进行样木伐倒造材,以实际经济材造材出材率为基础拟合并选择较优的单株木一元材积比方程,然后根据材积比方程进行理论造材并编制尾巨桉单株木一元经济材出材率表;接着利用单株木一元经济材出材率表对所调查的标准地进行理论造材,以林分理论造材出材率为基础拟合并选择较优的林分一元材积比方程,最后根据材积比方程研制尾巨桉林分一元经济材出材率表。所编制的数表均符合国家精度检验标准,可为本地区桉树生产经营提供参考。 相似文献
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本文论述了直径分布在林分结构和林分材种出材量表中的重要意义。介绍了使用Weibull直径函数研制林分材种出材量表的技术和方法。根据辽宁省人工落叶松林分资料,系统地介绍了利用一致性削度方程和Weibull直径函数编制林分材种出材量表的技术和方法。最后,对林分材种出材量表的一些技术和方法问题进行了讨论。 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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河南省杨树材种出材率表的研编 总被引：1，自引：0，他引：1
夏丰昌 《中南林业调查规划》2006,25(1):10-12
用削度方程和单株带皮—去皮胸径的转换关系式两个模型对河南省杨树进行计算机理论造材．经精度检验，满足要求，方法可行，依此编制了河南省杨树材种出材率表。 相似文献
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我国50～60年代初期,林业部综合队曾编制红松(Pinus koraiensis Sieb.et Zucc.)、云杉(Picea spp.)、马尾松(Pinus massoniana Lamb.)、兴安落叶松(Larix gmelini(Rupr.)Rupr.)、白桦(Betula platyphylla Suk.)等树种材种出材量表,70～80年代各省(区)市、规划院、科研等单位对杉(Cunninghamia lanceolata Hook.)、落叶松、山杨(Populus davidiana 相似文献
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The long term effects of superphosphate fertilization on stem form, taper and stem volume estimation of Pinus radiata on a phosphorus-deficient site was examined using data from a fertilizer experiment which had been maintained for 30 years. The application of superphosphate resulted in long term and statistically significant changes in stem form. Mean cylindrical form factor ranged from 0.33 for the control trees up to 0.40 for trees fertilized with 100 kg P ha−1. Stem form was also examined through taper curves which provided detailed depiction of average relative stem profiles. The increase in cylindrical form factor of fertilized trees was largely attributed to a significantly broader profile of the lower third of the stem. In comparison with the control trees, the fertilized trees also had a broader, although not statistically significant, profile of upper and middle stem which could also contribute to the increase in their cylindrical form factor. With increased form factor a greater proportion of the stem became merchantable because of increased log length to tree height ratio. Mean average taper of trees did not show a consistent trend with increasing lelevels of superphosphate application. It largely reflected the differential response of DBH and height growth to the treatments. The volume equation based on control trees underestimated the underbark stem volume of fertilized trees by 5–12% on average. Developing separate volume equations for the fertilized trees is warranted. 相似文献
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Marcos Barrio Anta Ulises Diéguez-Aranda Fernando Castedo-Dorado Juan Gabriel Álvarez González Klaus von Gadow 《Annals of Forest Science》2007,64(5):511-520
A model is required for accurate estimation of the merchantable volume of pedunculate oak (Quercus robur L.) trees in Galicia, northwestern Spain. Accordingly, the purpose of the present study was to obtain equations for predicting merchantable volumes and stem profiles of individual trees. For this reason, two compatible and four non-compatible volume systems were initially evaluated and fitted to data from 251 destructively sampled trees which were collected in stands located throughout the area of distribution of the species in Galicia. The outliers were removed to provide a data set of measurements from 3 090 sections, which was then available for fitting. A second-order continuous autoregressive error structure was used to account for autocorrelation. Comparison of the models was carried out using overall goodness-of-fit statistics and box plots of residuals against relative height or diameter class. The compatible volume system of Fang et al. [22] provided the best compromise in describing the stem profile and estimating merchantable height, merchantable volume and total volume and is therefore recommended for pedunculate oak stands in Galicia. 相似文献
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Compatible stem volume and taper equations for Brutian pine, Cedar of Lebanon, and Cilicica fir in Turkey 总被引：2，自引：0，他引：2
Compatible segmented taper and volume functions were developed for Brutian pine, Cedar of Lebanon, and Cilicica fir in Turkey. The proposed models generally performed better for the whole tree, especially for Cilicica fir. Average diameter prediction error was less than 2.2 cm and average volume error was less than 0.009 m3. The proposed models provide needed merchantable stem volume and diameter estimates to any point in the bole based on the 10 relative height classes examined for the three species. Model estimates compared well to existing volume tables currently employed for these three important commercial species. 相似文献
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本文提出了计算机理论造材仅根据削度方程和单株带,去皮胸径的转换关系式两个模型,可不必由削度方程推导材长方程和材积比方程。比相关指数,均方程为指标,结合残差图分析,选择了杉木、落叶松的削度方程;结合标准树高曲线,是可仅根据优势高为任一具体林分编制（一元）单株出材率表（特称之为自动调整出材率表）。 相似文献