共查询到19条相似文献,搜索用时 218 毫秒
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湖北省湿地松立木二元材积表的编制 总被引:6,自引:3,他引:3
湖北省湿地松栽培区只有少数单位编制出了立木材积表,而且大多具有临时性和偏差性,不仅精度达不到要求,应用范围也相当狭小,且各地区标准不一,可比性差。为此,本研究根据在“七·五”、“八·五”期间对全省湿地松栽培区的抽样调查资料中,挑选出有代表性的118根解析木材料,对每根解析木的年龄、树高、区分龄阶数、区分圆盘数和各圆盘年轮数、各龄阶检尺直径分别整理检算。通过解析计算,求算出各解析木的带皮直径、皮厚、带皮材积、去皮材积,用直接法编制出我省湿地松立木二元材积表。1回归模型的拟合在多个模型的比较上,选择山本… 相似文献
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楠木二元立木材积表试编 总被引:1,自引:0,他引:1
采用样木解析法收集和整理资料,探讨楠木材积与直径、树高之间的相关关系,建立楠木最佳二元立木材积方程,并编制楠木二元立木材积表,为楠木林分蓄积量测定等提供依据. 相似文献
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落叶松人工林树皮材积式的建立张向忠,王文勋,于晓宏,刘国泉(河北塞罕坝机械林杨,068466)商品木材,是以去皮材积为基础的,树皮材积方程是编制商品材收获表的依据。为此,我们收集资料,对落叶松人工林树皮材积与胸径和树高之间的关系进行了探讨。1样木的来... 相似文献
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皖北杨树二元立木材积表的编制 总被引:2,自引:0,他引:2
以安徽省杨树人工林为研究对象,按照立木材积表编制要求,随机抽取329棵杨树伐倒木材积资料.以300棵样木资料为编表样本,选用3种数学模型为二元材积的候选模型,利用非线性麦夸特迭代求解法确定各模型参数、剩余标准差、相关指数.根据相关指数和剩余标准差,确定最优二元材积模型为:V=0.000 096 93d2.0123h0.6147".以29棵样木资料为验表样本,分别计算二元材积模型理论材积与实际材积的平均相对误差、平均绝对相对误差和系统误差,计算结果为:二元材积表分别是2.7%、8.6%、0.1%.各种材积误差均满足林业生产材积估算误差要求. 相似文献
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带,去皮正形数系列之间的变化规律及应用 总被引:2,自引:0,他引:2
用陕西省主要林区收集的油松标准地、标准木分析了带、去皮正形数系列f_(0.nh)(0.n=0.0,0.02,0.04,0.06,0.08,0.1,0.15,0.2,0.25,0.3,0.4,0.5)之间的变化规律n对林分得到:当0.n=0.15时,f_(0.nh)(带皮)≈f_(0.n)(去皮);当0.n<0.15时,f_(0.nh)(带皮)f_(0.nh)(去皮)。单株木也是如此。应用关系式f_(0.15h)(带皮)≈f_(0.15h)(去皮),可根据0.15h处的带、去皮直径,得到树皮率系数,为准确估计单株木树干树皮率、去皮材积、树皮材积提供了一个新途径。经刺槐、红桦、白桦、山杨验证,也获得同样的结果。 相似文献
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陕西的油松林分或单株木用正形数f_(0.15h)与胸高形数、实验形数相比,其带、去皮值相对差异最小。应用关系式f_(0.15h)(带皮)≈f_(0.15h)(去皮),得到新的树皮率计算公式,并可根据带皮材积导算出去皮材积和树皮材积。当树高小于10m时,直接测定0.15h处带、去皮直径;当树高大于10m时,根据带、去皮胸径导算0.15h处带、去皮直径。 相似文献
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本文利用在管涔林区经营采伐标地内的伐倒木,按2cm 区分段实测各部分带皮去皮直径和稍端长度,计算带皮和去皮材积,按2cm 一个径阶进行归类,用Ⅴ=aD~bH~c分别对云杉和落叶松进行回归,求各径阶对应树高的材积,进而编制成管涔林区云杉落叶松二元材积表。通过对相关系数,单株材积检验,认为该表可在管涔林区使用。 相似文献
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柳树无性系人工林造林发展很快,为准确测定林分收获量,通过对各地苏柳172林分调查量测,共收集样木材积资料742株、样木重量资料130株,选用aD^bH^e模型编制了苏柳172人工林二元立木材积表和二元立木重量表。 相似文献
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目前调查和预测林木生长量(率)的方法有多种,此次我们采用胸径5年直径生长量的年龄材积差法,借助思茅松年龄——材积表,计算立木各龄阶的材积生长率。现将编制过程介绍于后。一、材料的收集样木材料是82年四大队专业队在梁河县三岔河林场测定的20块标准地的计算木88株、及与林场接壤地区样木500多株作为计算生长率 相似文献
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三明市材种出材率表编制是根据部、省有关材种规格标准,进行现场造材,共收集1164株样木,其中杉木556株,马尾松608株。采用电子计算机对样木进行计算和分析,以确定各树种树高级、径阶、材积、树皮率、出材量和出材率。 相似文献
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INTRODUCTIONWiththedevelopl11entofecono111yandoPeninghn1berInarket.thehlnbersizeiscaredaboutmorea11dl11ol'e.otl1ermse,l11uIhpleproductinventonesrequlresaccurateeshmatesofproductsizes(dial11eteral1dlengths)andvolume.Koreanpine(PinIisko1nIensisSib.etZucc.)isararehn1bersPeciesil1Heilol1roial1gProvince.ItisnecessarynotonlytopredicttI1evolumebasedonvolumetablebutalsotoas-sesstheassotheent.Accordingtothenahol1alhmbercritenonandthewoodqt1ality,thestandqualityisdetenl1i11ed.ThemainPOintofco… 相似文献
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E. K. Marsh 《Southern Forests》2013,75(1):2-8
The methods employed in the construction of new metric volume and percentage utilization tables for Eucalyptus grandis, based on 1 378 sample trees are described. Most of the complicated volume calculations were executed on a computer. Because of this, the formula for a frustum of a cone was used to calculate volumes of log sections. The logarithmic volume equation was used for the construction of the general volume table. It was found that bark thickness had a significant effect on the variation of tree volume. Therefore, volume tables for various bark thickness classes have been prepared in addition to a general table for average bark thickness. The relationship between breast height diameter and the percentage of the total volume to 2 inches tip represented by a given tip diameter class can be explained satisfactorily by regression of the probit transformation of the percentage volume on a polynomial of the reciprocal of breast height diameter. For metric conversion, the tip diameter class was introduced as an additional variable and the relationship was expressed by one equation for all the tip diameter classes combined. Imperial as well as metric equivalents of all equations established are given. 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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Carlos A López-Sánchez Roque Rodríguez-Soalleiro Sacramento Corral-Rivas Juan G Álvarez-González 《Southern Forests》2016,78(2):131-135
Five stem taper models belonging to three different taper function categories were fitted to data corresponding to 282 Pseudotsuga menziesii trees. The trees were selected in the area surrounding 61 research plots installed in Galicia, Asturias and the Basque Country, northern Spain. The models were simultaneously fitted to observed values of diameter outside bark and inside bark. A third-order continuous-time autoregressive error structure was used to account for autocorrelation. Selection of the best model was based on both numerical (goodness-of-fit statistics) and graphical analysis (plots of residuals against position along the stem and against tree size). The three-segmented taper model finally selected has the advantage of being compatible with both a merchantable and a total stem volume equation. 相似文献
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