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浙江大学学报（农业与生命科学版）
Journal of Zhejiang University (Agriculture and Life Sciences)  2015, Vol. 41 Issue (03): 340-348    DOI: 10.3785/j.issn.1008-9209.2014.06.162
Resource & environmental sciences     
Branching architectures of Caragana intermedia at different ages in desert steppe areas
Zhai Deping, Chen Lin, Yang Mingxiu, Song Naiping, Yang Xinguo*
(Key Laboratory for Restoration and Reconstruction of Degraded Ecosystem in North-Western China of Ministry of Education/Breeding Base for State Key Laboratory of Land Degradation and Ecological Restoration of North-Western China/Union Research Center for Ecology and Exploitation of Biological Resources in Western China, Ningxia University, Yinchuan 750021, China)
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Abstract  Caragana intermedia is a bush-like plant, and its branching architectures are more complex. Fractal theory provides a new tool for the study of trees and their properties. The crown characteristics of trees can be quantified by fractal dimensions, and the architectures can be described accurately. The relationships  between branching architectures and growth of C. intermedia were studied from the viewpoint of fractal theory, in order to study the branching architectures and adaptation strategies to the environment of C. intermedia in desert steppe areas. Based on the theory of fractal dimension in forestry application, the changes of branching architectures and strategies of ecological adaptation of C.  intermedia at different ages (growth for 16 a, 25 a, 37 a of intact plants and growth for 1 a, 5 a after stumping) were studied in desert steppe areas. The indexes of crown size, height and basal diameter of C.  intermedia increased firstly and then decreased with the increasing ages. Aboveground biomass of intact C.  intermedia at different ages decreased gradually with the increasing ages. Older shrubs (37 a) resisted the situation of senescence by self renewing. The ratio of branch diameter (RBD) of C.  intermedia shrubs which grew for one year after stumping was higher than those without stumping. The bearing capacity of shrub branches increased after stumping. The overall bifurcation ratio (OBR) and the lower-level stepwise bifurcation ratio (SBR1∶2 ) decreased with the increasing ages. The OBR and SBR1∶2 of shrubs which grew for one year after stumping were higher than the shrubs without stumping, but OBR and SBR1∶2 of shrubs which grew for 5 years after stumping decreased dramatically. The crown fractal dimensions (CFD) of shrubs without stumping were lower than 1, and  CFD decreased with the increasing ages. The CFD of shrubs after stumping were higher than 1, especially the shrubs which grew for five years after stumping were the highest. The bifurcation fractal dimensions (BFD) of shrubs without stumping decreased with the increasing ages. The BFD of shrubs which grew for one year after stumping were higher than those without stumping, and the BFD of shrubs which grew for five years after stumping were the lowest. At the module level, C. intermedia at the ages of 16 a, 25 a, 37 a presented a tendency of declining development. The branching pattern of 16 a shrubs was the most complex, and the ability to occupy the space and the potential of using spatial resources were higher. But the branching architecture of C. intermedia became simplified and the utilization potential of spatial resources and ecological adaptability declined with the increasing ages. Stumping was beneficial to stimulating the development of shrubs’ spatial patterns, and made branching architectures more complicated. The architectures development of shrubs which grew for 5 years after stumping mainly depended on branch length of different branch orders, and the branch number contributed little to it.

Published: 20 May 2015
CLC:  S 718.42  
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Articles by authors
Zhai Deping
Chen Lin
Yang Mingxiu
Song Naiping
Yang Xinguo
Cite this article:

Zhai Deping, Chen Lin, Yang Mingxiu, Song Naiping, Yang Xinguo. Branching architectures of Caragana intermedia at different ages in desert steppe areas. Journal of Zhejiang University (Agriculture and Life Sciences), 2015, 41(03): 340-348.

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http://www.zjujournals.com/agr/10.3785/j.issn.1008-9209.2014.06.162     OR     http://www.zjujournals.com/agr/Y2015/V41/I03/340


荒漠草原不同生长年限中间锦鸡儿灌丛枝系构型特征

基于分维数理论,对荒漠草原5个不同生长年限(未平茬16年、25年、37年生及平茬后1年、5年生)中间锦鸡儿(Caragana intermedia)灌丛的枝系构型变化进行分析,并探讨其生态适应策略。中间锦鸡儿灌丛的冠幅、株高、基径等指标基本随生长年限的增加呈先增大后降低趋势,未平茬中间锦鸡儿灌丛的地上生物量随林龄的增加呈下降趋势,老林龄(37年生)灌丛以自我更新的方式来抵制衰老的态势；平茬后1年与5年生中间锦鸡儿灌丛的枝径比(ratio of branch diameter,RBD)较未平茬16、25、37年林龄灌丛大,平茬后灌丛枝条间的承载力增大；中间锦鸡儿灌丛的总体分枝率(overall bifurcation ratio,OBR)以及低级枝的逐步分枝率(stepwise bifurcation ratio, SBR1∶2)随林龄增大而减小,平茬后1年生灌丛的OBR及SBR1∶2较未平茬3种年限林龄的灌丛大,但平茬后5年生灌丛的OBR和SBR1∶2急剧降低；未平茬灌丛的树冠分维数(crown fractal dimensions,CFD)较低,均小于1,且随林龄增大,树冠分维数降低。平茬后的灌丛CFD值大于1,尤以平茬后5年生灌丛为最大。未平茬灌丛的分枝分维数(bifurcation fractal dimensions, BFD)随林龄增大而减小,平茬后1年生灌丛BFD值大于未平茬灌丛,平茬后5年生灌丛BFD值最小。在构件水平上,16、25、37年生中间锦鸡儿灌丛出现衰退型发育的趋势。16年生中间锦鸡儿灌丛的枝系空间格局最为复杂,其占据空间的能力以及利用空间资源的潜能较高。但随着灌丛林龄的增加,中间锦鸡儿的枝系构型趋于简化,对空间资源的利用潜能和生态适应能力下降。平茬有利于刺激灌丛空间格局的发展,使灌丛枝系构型复杂化,但平茬后生长5年的灌丛,其构型发展主要以各级分枝枝长为主,分枝数对其贡献不大。
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