Departamento de Ciencias Forestales, Pontificia Universidad Católica de Chile, Chile.
Ann Bot. 2011 Oct;108(6):1155-78. doi: 10.1093/aob/mcr156.
Functional-structural models are interesting tools to relate environmental and management conditions with forest growth. Their three-dimensional images can reveal important characteristics of wood used for industrial products. Like virtual laboratories, they can be used to evaluate relationships among species, sites and management, and to support silvicultural design and decision processes. Our aim was to develop a functional-structural model for radiata pine (Pinus radiata) given its economic importance in many countries.
The plant model uses the L-system language. The structure of the model is based on operational units, which obey particular rules, and execute photosynthesis, respiration and morphogenesis, according to their particular characteristics. Plant allometry is adhered to so that harmonic growth and plant development are achieved. Environmental signals for morphogenesis are used. Dynamic turnover guides the normal evolution of the tree. Monthly steps allow for detailed information of wood characteristics. The model is independent of traditional forest inventory relationships and is conceived as a mechanistic model. For model parameterization, three databases which generated new information relating to P. radiata were analysed and incorporated.
Simulations under different and contrasting environmental and management conditions were run and statistically tested. The model was validated against forest inventory data for the same sites and times and against true crown architectural data. The performance of the model for 6-year-old trees was encouraging. Total height, diameter and lengths of growth units were adequately estimated. Branch diameters were slightly overestimated. Wood density values were not satisfactory, but the cyclical pattern and increase of growth rings were reasonably well modelled.
The model was able to reproduce the development and growth of the species based on mechanistic formulations. It may be valuable in assessing stand behaviour under different environmental and management conditions, assisting in decision-making with regard to management, and as a research tool to formulate hypothesis regarding forest tree growth and development.
功能结构模型是将环境和管理条件与森林生长联系起来的有趣工具。它们的三维图像可以揭示用于工业产品的木材的重要特征。就像虚拟实验室一样，它们可以用于评估物种、地点和管理之间的关系，并支持造林设计和决策过程。我们的目标是为辐射松（Pinus radiata）开发一个功能结构模型，因为它在许多国家具有重要的经济意义。
该植物模型使用 L 系统语言。模型的结构基于操作单元，这些操作单元根据其特定特征遵守特定规则并执行光合作用、呼吸和形态发生。植物的比例生长被遵守，以实现和谐生长和植物发育。使用形态发生的环境信号。动态更替指导树木的正常进化。每月的步骤允许获得木材特征的详细信息。该模型独立于传统的森林清查关系，被设想为一种机械模型。为了模型参数化，分析和合并了三个生成与辐射松有关的新信息的数据库。
在不同和对比的环境和管理条件下运行模拟并进行了统计测试。该模型针对相同的地点和时间的森林清查数据以及真实的树冠结构数据进行了验证。对于 6 年生树木的模型性能令人鼓舞。总高度、直径和生长单元的长度得到了充分估计。树枝直径略有高估。木材密度值不太令人满意，但生长轮的周期性模式和增加得到了合理的模拟。
该模型能够基于机械公式再现物种的发育和生长。它可以在评估不同环境和管理条件下的林分行为方面具有价值，有助于对管理做出决策，并作为研究工具来制定关于森林树木生长和发育的假设。
