Allometric growth and allocation in forests: a perspective from FLUXNET.
Allometric growth and allocation in forests: a perspective from FLUXNET.
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DOI：
10.1890/10-1201.1
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发表时间：
2011-07
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影响因子：
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通讯作者：
A. Wolf;C. Field;J. Berry
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文献类型：
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作者：
A. Wolf;C. Field;J. Berry
为了开发一个计划，用于分区的光合作用的产品对不同的生物量组成部分的陆面模型，组件质量和净初级生产力（NPP），从FLUXNET网站收集的数据库，进行了检查，以确定异速生长模式的分配。结果表明，单株植物的叶、枝、粗根和细根的NPP在很大程度上（r ~ 2 = 67-91%）可以用单株植物的总NPP（G）来解释。Gfol与G等距缩放，这意味着它是G的固定分数（25%）。根冠权衡表现为Gfroot的缓慢下降，作为G的一部分，从50%到25%，随着林分生物量的增加，Gstem和Gcroot随之增加。这些结果表明，地上和地下分配之间的功能权衡基本上是捕获的变化G，这本身主要是由林分生物量，只有次要的特定网站的资源可用性。我们认为，森林的特点是对光线的强烈竞争，观察作为一个种族的个别树木上升，增加分配木材，而不是通过增长更多的叶子，这种竞争强烈地限制了分配可塑性，树木可能是有能力的。在分区的残留变化是不相关的气候或土壤因素，也没有与营养或水补充地块显示出的分区模式不同的预测由G单独。这些研究结果利用陆地碳循环的短期过程研究，以改善森林生物量积累的十年尺度预测。提出了一种陆面模式分区计算的算法。
To develop a scheme for partitioning the products of photosynthesis toward different biomass components in land-surface models, a database on component mass and net primary productivity (NPP), collected from FLUXNET sites, was examined to determine allometric patterns of allocation. We found that NPP per individual of foliage (Gfol), stem and branches (Gstem), coarse roots (Gcroot) and fine roots (Gfroot) in individual trees is largely explained (r2 = 67-91%) by the magnitude of total NPP per individual (G). Gfol scales with G isometrically, meaning it is a fixed fraction of G ( 25%). Root-shoot trade-offs were manifest as a slow decline in Gfroot, as a fraction of G, from 50% to 25% as stands increased in biomass, with Gstem and Gcroot increasing as a consequence. These results indicate that a functional trade-off between aboveground and belowground allocation is essentially captured by variations in G, which itself is largely governed by stand biomass and only secondarily by site-specific resource availability. We argue that forests are characterized by strong competition for light, observed as a race for individual trees to ascend by increasing partitioning toward wood, rather than by growing more leaves, and that this competition stronglyconstrains the allocational plasticity that trees may be capable of. The residual variation in partitioning was not related to climatic or edaphic factors, nor did plots with nutrient or water additions show a pattern of partitioning distinct from that predicted by G alone. These findings leverage short-term process studies of the terrestrial carbon cycle to improve decade-scale predictions of biomass accumulation in forests. An algorithm for calculating partitioning in land-surface models is presented.