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1.
基于冠幅直径和植株高度的灌木地上生物量估测方法研究   总被引:26,自引:0,他引:26  
采用冠幅直径和植株高度两个易测因子,以河蒴荛花为例,用数理统计方法构建了该灌木地上生物量和枝、叶生物量估测模型.  相似文献   

2.
【目的】探讨简单、方便且能准确估算盐沼植物生物量的方法,简化其生物量测定工作。【方法】以高度(H)和密度(D)2个形态因子作为变量,用数理统计方法构建茳芏(Cyperus malaccensis Lam.)生物量估测模型。【结果】茳芏地上生物量(Wa)以DH为变量进行估测更恰当,以DH为自变量的乘幂曲线模型Wa=0.0097(DH)1.177为生物量最佳估测模型。【结论】运用回归模型估算茳芏地上生物量可行,并可取得较为可靠的预测精度,茳芏地下生物量不能得出合适的估算方程。  相似文献   

3.
采用幂函数生物量模型,对喀斯特森林不同林分环境中136株 2~9年生光皮桦幼树的地上部分、树干、枝和叶生物量的分配关系进行研究,得出了林缘木生物量地上部分、干、枝、叶的估测模型,模型的拟 合优度均在090以上。对比分析表明地径模型最客观反映林木生物量变化规律,该模型适用的地径范围为04~80cm。  相似文献   

4.
1992年3月在广西北海半岛大冠沙白骨壤群落研究了白骨壤植株的测树因子跟地上部生物量间的相关性。结果显示,由于白骨壤植株形态多变,树高通常小于2.0m,树高在估算地上部生物量时并不重要。植株的生物量可较好地用下述方程估算:茎:W=0.8496-0.4429D+0.0748D~2枝:W=-2.2744+1.5595e~(-H)+1.0590C+0.0606D~2叶:W=0.0180D~(2.1294)地上部分生物量:W=-2.4386+0.0081H/LnH+1.4796C+0.0991D~2式中 H 为树高(m),D 为基茎(cm),C 为冠幅(m~2),W 为干重(kg)。文中还给出了利用这些方程估算群落生物量的范例。  相似文献   

5.
江西杉木人工林生物量分配格局及其模型构建   总被引:1,自引:0,他引:1  
在省级尺度上分析不同林龄杉木生物量数据,以探索江西省杉木人工林生物量的动态分配格局及其准确估算方法。结果表明:江西省杉木人工林生物量变化范围为55.64~165.22 t/hm2,其乔木层生物量占94.2%以上。杉木林及其乔木层生物量随林龄先增加后略微下降,而各林龄的灌木层、草本层和凋落物层生物量均没有显著差异。幼龄林、近熟林、成熟林各组分生物量大小排序均为乔木层>凋落物层>灌木层>草本层,而在中龄林和过熟林中则为乔木层>凋落物层>草本层>灌木层。幼龄林各器官生物量大小排序为树干>叶>根>枝,而其他林龄中的排序均为树干>根>枝>叶。以胸径(D)为单变量的杉木单株生物量(W)模型(W=0.266D2.069)及以胸径(D)和树高(H)为变量的模型(W=0.046 9(D2H)0.906 4)预测值小于测量值,且预测精度R2均为0.84,其精度和预测能力均低于以胸径、林龄(A)、密度(N)为自变量的生物量模型(W=11.497D1.847A0.082N-0.478)。  相似文献   

6.
日本落叶松人工林生物量及生产力的研究   总被引:5,自引:0,他引:5  
在长岭岗国营林场调查了日本落叶松人工林林分24块标准地,并测定了单株平均木的各器官生物量,结果表明:应用W=a(D^2H)^b模型来估测日本落叶松人工林生物量,其相关程度达显著水平;日本落叶松人工林单株林木各器官的生物量随年龄变化符合理查德(Richards)生长方程;日本落叶松人工林单株林木生物量年平均生长量在26a时达到顶峰;日本落叶松人工林林分生物量24a时达293.40t/hm^2,生产力为20.78t/(hm^2.a).  相似文献   

7.
光皮桦种群生物量的测定   总被引:11,自引:3,他引:8  
用相对生长模型W=a(D^2H)^b和幂函数改进模型W=aD^αH^β,对福建邵武卫闽光皮桦种群生物量进行了研究。结果表明,幂函数改进模型要优于相对生长模型,并且光皮桦林分总生物量为33.47t/hm^2,其生物量大小顺序为树干>根>枝>皮>叶。  相似文献   

8.
桂林岩溶石山主要灌丛类型地上生物量及分配特征   总被引:1,自引:0,他引:1  
以桂林岩溶石山主要灌丛类型:紫凌木灌丛Decaspermum esquirolii Shrub、檵木灌丛Loropetalum chinense Shrub、龙须藤灌丛Bauhinia championii Shrub、小果蔷薇灌丛Rosa cymosa Shrub、红背山麻杆灌丛Alchornea trewioides Shrub为研究对象,采用群落学调查法研究这5种灌丛类型地上生物量分配特征.结果表明:5种灌丛类型地上生物量大小顺序为:紫凌木灌丛>小果蔷薇灌丛>龙须藤灌丛>檵木灌丛>红背山麻杆灌丛,生物量分别为:29.48 t/hm2,18.76 t/hm2,15.18 t/hm2,9.78 t/hm2,7.54 t/hm2.5种灌丛群落地上生物量平均为16.15 t/hm2,不同层次生物量大小顺序为:灌木层>枯枝落叶层>草本层,各自生物量占地上生物量的比例分别为81.67%、11.89%和6.44%.对于5种灌丛类型建群种生物量所占各自灌丛灌木层生物量的比例而言,其大小顺序为:红背山麻杆>檵木>小果蔷薇>龙须藤>紫凌木.  相似文献   

9.
长白山区林下主要灌木生物量估算与分析   总被引:4,自引:0,他引:4  
以长白山金沟岭林场天然云冷杉林、杨桦次生林、人工落叶松林3种森林类型为研究对象,构建了林下灌木层分布较广泛的10个物种以植冠面积(Ac)、植冠体积(Vc)、地径平方与株高乘积(D2H)为自变量的器官生物量模型,并按照灌木形态的不同分别乔木型灌木(主干明显)、典型灌木(分枝多,主干不明显)构建混合物种模型,选出R2较大、SEE较小的模型作为最优模型,研究了不同森林类型林下灌木层生物量及其在不同物种和器官中的分配。结果表明:单一物种器官生物量最优模型多为线性、二次或者三次方程,干、枝最优模型采用的自变量多为D2H或者Vc,叶生物量最优模型采用的自变量多为Ac或者Vc,根的多为D2H。混合物种模型的最优方程为幂函数或三次方程,最优模型的自变量除典型灌木枝模型为Vc外,其他各器官模型自变量都为D2H。计算得到的天然云冷杉林、杨桦次生林、人工落叶松林林下灌木层生物量分别为4 01359、3 95066和4 64936 kg/hm2,且乔木型灌木对生物量的贡献率大于典型灌木。  相似文献   

10.
以内蒙古鄂尔多斯毛乌素沙地优势灌从沙柳(Salix psammophila)为研究对象,利用其易测指标株高(H)和冠幅直径(D)作为变量,结合实地获取的沙柳地上生物量与地下根系生物量,进行回归分析构建沙柳生物量模型.通过综合对比分析各预测模型的判定系数(R2)、F检验和平均估算误差(AEE)等指标,筛选出沙柳最佳生物量估测模型.沙柳生物量的最优模型为:地上生物量WA=0.326(HD)1.831,地下(根系)生物量WR=0.343(HD)1.497,总生物量WT=0.72(HD)1.660.模型的建立为毛乌素沙地沙柳群落生物量的测定提供了一种简便、实用的方法.  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.  相似文献   

13.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

14.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

15.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

16.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

17.
There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.  相似文献   

18.
本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。  相似文献   

19.
In the 19th century the society was controlled by men, and women were just appendants of them, they had not any rights and freedom. But Jane was an exception, she showed some characteristics of early feminist. Jane showed her characteristics of feminism in three aspects: rebellion, equality, and independence. These characteristics were helpful to her success, and feminism is the only way out for women of that time.  相似文献   

20.
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