首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到17条相似文献,搜索用时 156 毫秒
1.
本文以马尾松(Pinus massoniana)地上生物量数据为例,通过利用度量误差模型方法,研究建立了地上生物量与干、皮、枝、叶4个分量的相容性方程系统。首先,从各个分量所占比例变化特点分析入手,采用比值函数分级联合控制和比例函数总量直接控制2种方案构建了以地上总生物量为基础的相容性方程系统,其中对地上总生物量模型的估计,又采取了独立估计和联合估计2种处理方法。结果表明,分级联合控制方案和总量直接控制方案效果基本相当,而独立估计方法和联合估计方法也几乎没有差异。然后,还对一元、二元和三元模型的拟合效果进行了对比分析,结果显示随着解释变量的增加,估计值的标准误差和平均预估误差会有所下降,但对模型效果的改善幅度并不大。最后,对各个分量占地上总生物量的比例随直径的变化特点进行了分析,结果表明干材生物量所占比例随林木直径的增大而提高,干皮和树叶生物量所占比例则随林木直径的增大而下降,而树枝生物量所占比例相对比较稳定。本文所建立的相容性生物量方程系统,地上总生物量的预估精度达到95%以上,树叶生物量的预估精度最低,但也达到了85%以上。  相似文献   

2.
含地域和起源因子的马尾松立木生物量与材积方程系统   总被引:1,自引:0,他引:1  
【目的】建立含地域和起源因子的相容性立木生物量与材积方程系统,为准确估计森林生物量提供依据。【方法】以我国南方主要针叶树种马尾松为研究对象,基于301和104株样木的实测地上生物量、树干材积和地下生物量数据,综合利用哑变量建模方法和误差变量联立方程组方法,建立集地上生物量、树干材积和地下生物量为一体、确保与生物量转换因子和根茎比等变量相容的一元和二元方程系统,并分析立木生物量和材积估计是否受地域和起源的影响。【结果】所建立的马尾松一元和二元相容性立木生物量方程与材积方程,确定系数(R~2)均在0.92以上,其中地上生物量方程的平均预估误差在4%以内,地下生物量方程的平均预估误差在8%以内。对马尾松地上生物量和树干材积的估计,二元模型均显著优于一元模型,其F统计量远大于临界值;但对地下生物量的估计,二元模型反而不如一元模型效果好。不论是一元模型还是二元模型,地域和起源对马尾松地上生物量估计均无显著影响,地上生物量模型具有很好的通用性,同时也进一步印证了曾伟生等(2012)提出的通用性地上生物量模型M=0.3ρD~(7/3)的广泛适用性。对马尾松地下生物量的估计,不同地域的模型存在显著差异;相同直径的林木,总体1地域范围内(长江流域东南部)的地下生物量要大于总体2(长江流域中西部)。对马尾松树干材积的估计,二元模型不受地域和起源影响,但一元模型受起源影响;相同直径的林木,人工林的材积估计值大于天然林。【结论】将哑变量引入误差变量联立方程组,可同时解决多个变量之间的相容性及地上生物量和地下生物量样本单元数不相等时如何联合建模的问题,是切实可行的生物量建模方法;研究所建立的马尾松立木生物量方程、材积方程及其相容的生物量转换因子和根茎比方程,达到相关技术规定预估精度要求,可推广应用。  相似文献   

3.
云南省云杉立木生物量模型研建   总被引:2,自引:0,他引:2  
以云南云杉为研究对象,对云杉地上生物量和地下生物量模型进行研建。建立云杉地上总生物量、树干、树冠、干材、干皮、树枝、树叶独立模型与材积相容模型,采用分级联合控制和度量误差模型方法,建立地上总生物量和所有分量相容的立木生物量模型,建立根茎比模型对云杉地下生物量进行估计。结果表明:建立的云杉地上总生物量、树干、干材生物量二元模型预估精度均达95%以上,干皮生物量模型预估精度达94%以上,树冠、树叶、树枝生物量的预估精度均在92%以上,地下生物量模型预估精度在88%以上;所建立的模型可以用于云杉生物量的估计。  相似文献   

4.
广东主要乡土阔叶树种含年龄和胸径的单木生物量模型   总被引:1,自引:0,他引:1  
【目的】建立樟树、木荷和枫香3个树种以胸径、年龄为自变量的单木地上生物量模型,为精准估计森林生物量和碳储量变化规律提供理论、实践支撑和技术支持。【方法】基于每个树种按10个径阶均匀分配的90株伐倒木数据(3个树种共270株伐倒木),使用破坏性试验和树干解析分别获取生物量和年龄,采用哑变量方法区分起源,分别建立和比较3个树种不同起源(天然林和人工林)含胸径、年龄和2种常用的含胸径、树高单木地上生物量模型,并通过联立方程组总量控制法解决地上部分各组分(干材、树皮、树枝、树叶)的模型相容性问题。【结果】3个树种3个地上生物量模型修正的确定系数(R■)在0.89~0.94之间,使用含胸径、年龄的生物量模型(1)估计地上生物量是可行的,模型具有良好的估计效果且方便使用。增加哑变量后,3个树种3个地上生物量模型的R■均达0.90以上,模型(4)可以进一步提高模型精度,细化模型应用条件;基于B-D-T的相容性生物量模型系统(7)3个树种树干生物量模型的R■在0.90~0.95之间,树皮生物量模型的R■在0.84~0.94之间,树枝生物量模型的R■在0.73~0.91之间,树叶生物量模型的R■在0.63~0.75之间;构建含有哑变量的B-D-T相容性生物量模型系统(8),树干生物量模型的R■在0.88~0.97之间,树皮生物量模型的R■在0.82~0.93之间,树枝生物量模型的R■在0.84~0.90之间,树叶生物量模型的R■在0.62~0.69之间,表明含胸径、年龄的生物量模型比含胸径、树高的生物量模型效果更好,满足估计需求。【结论】含胸径、年龄的单木地上生物量模型(1)和分起源的单木地上生物量哑变量模型(4)拟合精度均高于2种常用的含胸径、树高的单木地上生物量模型(2)和(3)以及分起源的单木地上生物量模型(5)和(6),含哑变量的非线性联立方程组(8)比B-D-T模型系统(7)精度更高,同时含胸径、年龄的哑变量非线性联立方程组(8)精度指标也优于含胸径、树高的哑变量联立方程组(9)和(10),联立方程组(8)不仅可保证不同起源各分量生物量之间的相容性,还能得到更优化的参数估计。含胸径、年龄的单木生物量模型(1)和考虑起源的地上生物量模型(4)、模型系统(7)中的含胸径、年龄的地上各组分生物量相容性方程组以及考虑起源的地上各组分生物量相容性方程组(8)比2种常用的含胸径、树高的地上生物量模型拟合精度高,实践中更适用于人工阔叶林和碳汇造林项目的碳汇计量、监测和评估。  相似文献   

5.
南方马尾松不同器官的含碳系数分析   总被引:1,自引:0,他引:1  
为了应对全球气候变化,森林碳储量监测日益受到重视,而含碳系数是一项重要的基础计量指标.以南方马尾松为对象,利用假设检验和回归分析方法,对不同器官的含碳系数进行系统分析.结果表明:马尾松不同器官的含碳系数存在显著差异,从大到小依次为树叶>干材>树根>树枝>干皮;树干不同高度干材和干皮的含碳系数也存在明显差异,但不同层次树...  相似文献   

6.
浙江舟山地区马尾松地上生物量模型研究   总被引:7,自引:0,他引:7  
基于浙江舟山地区马尾松标准地的调查和几种常用的树木单株生物量估测模型,选择单个因子和多因子组合,分别对马尾松地上总生物量、树干生物量、树枝生物量和树叶生物量进行建模,并对各种模型进行误差分析,从中挑选最优的估测模型,可以在一定精度保证下,用于该地区马尾松生物量估测。  相似文献   

7.
基于60株辽东山区日本落叶松样木生物量的实测数据,分析不同林龄条件下立木各部分生物量的变化情况,并应用度量误差方法建立立木相容性生物量模型。结果表明:树叶、树枝、树皮生物量占总生物量的比值随林龄增长呈下降趋势,干材占总生物量的比值随林龄增长呈上升趋势。在筛选出总生物量与各分量最优独立模型的基础上,应用三级控制的方法建立生物量相容性模型,并采用加权回归方法消除总量和各分量模型的异方差。建立的总量、地上部分、树干、干材、树皮生物量模型,其R2均大于0.9;树根、树冠、树叶和树枝生物量的R2略低,介于0.7 0.9之间。通过独立样本对模型的相容性和预测精度进行检验,各分量预测值所占总生物量的百分比之和为1,模型完全相容;根、冠、叶和枝的模型预测精度略低于90%,其他部位模型的预测精度都在95%以上,模型的预测精度较高。  相似文献   

8.
桂西北马尾松人工林生物量生长规律及其分配模式   总被引:2,自引:0,他引:2  
对桂西北马尾松人工林的单木生物量相对生长模型、林分生物量及其分配规律的研究结果表明:(1)马尾松树干、树皮、地上生物量、地下生物量以及总生物量以方程W=a×(D2H)b的拟合效果为好,树枝和树叶以方程W=a×Db的拟合效果为好。(2)不同林龄马尾松林分标准木各器官的生物量所占总生物量的百分比出现明显的变化。在不同的马尾松林龄中,各器官的生物量均以树干为最高,同时随着林龄的增加,其所占百分比例出现明显的升高,随着林龄的继续增大,其所占百分比逐渐趋于稳定。与树干的变化趋势相反,树皮、树枝、树叶和树根的所占总生物量百分比随着林龄的增加而呈现下降。(3)林分生物量随着林龄的增大而出现明显的增加。林分树干和树枝的总生物量和所占百分比均出现明显的上升;树皮和树叶的总生物量随林龄的增加而增加,但其所占乔木层总生物量的百分比则随着林龄的增加而下降;地下生物量随林龄的增大而无显著变化。  相似文献   

9.
马尾松阔叶树混交效果分析   总被引:3,自引:0,他引:3  
在分析闽粤栲+马尾松、光皮桦+马尾松混交林及马尾松纯林土壤化学性质差异的基础上,探讨了闽粤栲+马尾松、光皮桦+马尾松混交林及马尾松纯林生长量、地上部分生物量及分配率。研究结果表明,闽粤栲+马尾松及光皮桦+马尾松混交林在改良地力、促进马尾松生长及生物量积累等方面均优于马尾松纯林;闽粤栲+马尾松混交林改良地力的能力略强于光皮桦+马尾松混交林,光皮桦+马尾松混交林中马尾松生长量高于闽粤栲+马尾松混交林;各树种干材生物量分配率最大,其次为树枝和树叶;叶的分配率大小为光皮桦+马尾松混交林>马尾松纯林>闽粤栲+马尾松混交林,枝的分配率大小为光皮桦+马尾松混交林>闽粤栲+马尾松混交林>马尾松纯林。  相似文献   

10.
[目的]研究建立地上生物量与地下生物量、立木材积之间相容,以及地上生物量与各分量之间可加的一体化生物量模型系统,为准确估计森林生物量提供定量依据。[方法]以新疆自治区的云杉(Picea spp.)为研究对象,基于230株和78株样木的实测地上生物量、树干材积和地下生物量数据,综合利用误差变量联立方程组方法和哑变量建模方法,研究建立集地上生物量、树干材积和地下生物量为一体,兼具相容性和可加性的二元和一元生物量模型系统,并分析一元模型是否受地域的影响。[结果]所建云杉一元和二元一体化生物量模型系统,地上生物量方程的平均预估误差在7%以下,干、皮、枝、叶各分项生物量方程的平均预估误差在10%左右,地下生物量方程的平均预估误差在15%以下,均达到了相关技术规定的预估精度要求。除了干材和树皮生物量的估计效果不如二元模型外,一元模型对其它各项生物量的估计均要优于二元模型。比例控制法和代数控制法均能解决地上生物量与干、皮、枝、叶各分项生物量之间的可加性问题,且两种方法得出的模型预估结果无显著差异。[结论]将哑变量引入误差变量联立方程组,不仅能解决地上生物量和地下生物量样本单元数不相等时如何联合建模的问题,还能同时解决地上生物量与地下生物量和立木材积之间的相容性问题及地上生物量与各分量之间的可加性问题,方法切实可行;对地上生物量、地下生物量及立木材积的估计,含区域因子的哑变量模型均要优于总体平均模型。  相似文献   

11.
Forest biomass estimation at large scale has become an important topic in the background of facing global climate change, and it is fundamental to develop individual tree biomass equations suitable for large-scale estimation. Based on the measured data of biomass components and stem volume from 100 sample trees of two larch species (Larix gmelinii and L. principis-rupprechtii) in northeastern and northern China, an integrated equation system including individual tree biomass equations, stem volume equation and height–diameter regression model were constructed using the dummy variable model and error-in-variable simultaneous equations. In the system, all the parameters of equations were estimated simultaneously, so that the aboveground biomass equation was compatible to stem volume equation and biomass conversion factor (BCF) function; the belowground biomass equation was compatible to root-to-shoot ratio (RSR) function; and stem wood, stem bark, branch and foliage biomass equations were additive to aboveground biomass equation. In addition, the system also ensured the compatibility between one- and two-variable models. The results showed that: (1) whether aboveground biomass equations or belowground biomass equations and stem volume equations, the estimates for larch in northeastern China were greater than those in northern China; (2) BCF of a larch tree decreased with the growing diameter while RSR increased with the growing diameter; (3) the proportion of stem wood biomass to aboveground biomass increased with the growing diameter while those of stem bark, branch, and foliage biomass decreased.  相似文献   

12.
Calorific value of plants is an important parameter for evalu- ating and indexing material cycles and energy conversion in forest eco- systems. Based on mensuration data of 150 sample sets, we analyzed the calorific value (CV) and ash content (AC) of different parts of Masson pine (Pinus massoniana) trees in southern China using hypothesis testing and regression analysis. CV and AC of different tree parts were almost significantly different (P〈0.05). In descending order, ash-free calorific value (AFCV) ranked as foliage 〉 branch 〉 stem bark 〉 root 〉 stem wood, and AC ranked as foliage 〉 stem bark 〉 root 〉 branch 〉 stem wood. CV and AC of stem wood from the top, middle and lower sections of trees differed significantly. CV increased from the top to the lower sections of the tnmk while AC decreased. Mean gross calorific value (GCV) and AFCV of aboveground parts were significantly higher than those of belowground parts (roots). The mean GCV, AFCV and AC of a whole tree of Masson pine were 21.54 kJ/g, 21.74 kJ/g and 0.90%, re- spectively. CV and AC of different tree parts were, to some extent, cor- related with tree diameter, height and origin.  相似文献   

13.
Regressive models of the aboveground biomass for three conifers in subtropical China—slash pine (Pinus elliottii), Masson pine (P. massoniana) and Chinese fir (Cunninghamia lanceolata)—were established. Regression analysis of leaf biomass and total biomass of each branch against branch diameter (d), branch length (L), d 3 and d 2 L was conducted with functions of linear, power and exponent. A power law equation with a single parameter (d) was proved to be better than the rest for Masson pine and Chinese fir, and a linear equation with parameter (d 3) is better for slash pine. The canopy biomass was derived by adopting the regression equations to all branches of each individual tree. These kinds of equations were also used to fit the relationship between total tree biomass, branch biomass, foliage biomass and tree diameter at breast height (D), tree height (H), D 3 and D 2 H, respectively. D 2 H was found to be the best parameter for estimating total biomass. However, for foliage biomass and branch biomass, both parameters and equation forms showed some differences among species. Correlations were highly significant (P<0.001) for foliage biomass, branch biomass and total biomass, among which the equation of the total biomass was the highest. With these equations, the aboveground biomass of Masson pine forest, slash pine forest and Chinese fir forest were estimated, in addition to the allocation of aboveground biomass. The above-ground biomass of Masson pine forest, slash pine forest and Chinese fir forest was 83.6, 72.1 and 59 t/hm2 respectively, and the stem biomass was more than the foliage biomass and the branch biomass. The underground biomass of these three forests which estimated with others’ research were 10.44, 9.42 and 11.48 t/hm2, and the amount of carbon-fixed were 47.94, 45.14 and 37.52 t/hm2, respectively. __________ Translated from Chinese Journal of Applied Ecology, 2006, 17(8): 1382–1388 [译自: 应用生态学报]  相似文献   

14.

Key message

A climate-sensitive aboveground biomass (AGB) equation, in combination with nonlinear mixed-effects modeling and dummy variable approach, was developed to examine how climate change may affect the allometric relationships between tree diameter and biomass. We showed that such changes in allometry need to be taken into account for estimating tree AGB in Masson pine.

Context

As a native species and being widely distributed in subtropical China, Masson pine (Pinus massoniana Lamb.) forests play a pivotal role in maintaining forest ecosystem functions and mitigation of carbon concentration increase at the atmosphere. Traditional biomass allometric equations do not account for a potential effect of climate on the diameter–biomass relationships. The amplitude of such an effect remains poorly documented.

Aims

We presented a novel method for detecting the long-term (2041–2080) effects of climate change on the diameter–biomass relationships and the potential consequences for long-term changes of biomass accumulation for Masson pine.

Methods

Our approach was based on a climate-sensitive AGB model developed using a combined nonlinear mixed-effects model and dummy variable approach. Various climate-related variables were evaluated for their contributions to model improvement. Heteroscedasticity was accounted for by three residual variance functions: exponential function, power function, and constant plus function.

Results

The results showed that diameter at breast height, together with the long-term average of growing season temperature, total growing season precipitation, mean temperature of wettest quarter, and precipitation of wettest quarter, had significant effects on values of AGB. Excessive rain during the growing season and high mean temperature in the wettest quarter reduced the AGB, while a warm growing season and abundant precipitation in the wettest quarter increased the AGB.

Conclusion

Climate change significantly affected the allometric scale of biomass equation. The new climate-sensitive allometric model developed in this study may improve biomass predictions compared with the traditional model without climate effects. Our findings suggested that the AGB of Masson pine trees with the same diameter at breast height under three climate scenarios including representative concentration pathway (RCP) 2.6, RCP 4.5, and RCP 8.5 in the future period 2041–2080 would increase by 24.8 ± 32.7% (mean ± standard deviation), 27.0 ± 33.4%, and 27.7 ± 33.8% compared with the constant climate (1950–2000), respectively. As a consequence, we may expect a significant regional variability and uncertainty in biomass estimates under climate change.
  相似文献   

15.
Because of global climate change,it is necessary to add forest biomass estimation to national forest resource monitoring.The biomass equations developed for forest biomass estimation should be compatible with volume equations.Based on the tree volume and aboveground biomass data of Masson pine(Pinus massoniana Lamb.) in southern China,we constructed one-,two-and three-variable aboveground biomass equations and biomass conversion functions compatible with tree volume equations by using error-in-variable simultaneous equations.The prediction precision of aboveground biomass estimates from one variable equation exceeded 95%.The regressions of aboveground biomass equations were improved slightly when tree height and crown width were used together with diameter on breast height,although the contributions to regressions were statistically insignificant.For the biomass conversion function on one variable,the conversion factor decreased with increasing diameter,but for the conversion function on two variables,the conversion factor increased with increasing diameter but decreased with increasing tree height.  相似文献   

16.
Comparison of branch-level foliage and branch (wood+bark) biomass relationships for North Carolina Coastal (NCC) and Oklahoma/Arkansas (O/A) loblolly pine (Pinus taeda L.) seed sources provided an indication of biomass partitioning differences between these two seed sources. The objective of this study was to quantify and compare the branch-level foliage and branch biomass of NCC and O/A provenances on an excessively drained site in southeastern Oklahoma to assess their branch-level biomass partitioning patterns; a modeling process was developed to accomplish this objective. It was found that seed source significantly influenced the amount of foliage per branch. If tree and branch dimensions were held constant, NCC branches would carry approximately 30% more foliage per branch than O/A branches. The relationship between tree and branch dimensions and branch production did not differ for the two seed sources. Vertical distributions of branch and foliage biomass were found to be similar for the two seed sources as well. Thus, on the droughty site observed in this study: (1) the NCC seed source tended to partition more biomass into the foliage component at the individual branch level than did the O/A seed source; (2) the two seed sources were similar in their propensity to partition biomass into the branch component at the branch level, and (3) the two seed sources were similar in the vertical distribution of branch and foliage biomass within the crown.  相似文献   

17.
马尾松是我国松属树种中地理分布最广的一种,也是南方的造林先锋树种和主要用材树种。文中从物理力学性能、纤维特性以及渗透性等方面论述了马尾松木材材性特点,介绍了马尾松木材干燥及脱脂处理技术、木材蓝变及其防治方法,总结了马尾松木材在实木利用、人造板生产等领域的应用现状,展望了马尾松木材加工利用的发展前景。  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号