ABSTRACT

Very few spatially explicit tree models have so far been constructed with a view to project remote-sensing data directly. To fill this gap, we introduced the prototype of the CanopyShotNoise model, an individual-based model specifically designed for projecting airborne laser scanning (ALS) data. Given the nature of ALS data, the model focuses on the dynamics of individual-tree canopies in forest ecosystems, that is, spatial tree interaction and resulting growth, birth and death processes. In this study, CanopyShotNoise was used to analyse the long-term effects of the processes crown plasticity (C) and superorganism formation (S) on spatial tree canopy patterns that are likely to play an important role in ongoing climate change. We designed a replicated computer experiment involving the four scenarios C0S0, C1S0, C0S1 and C1S1 where 0 and 1 imply that the preceding process was switched off and on, respectively. We hypothesized that C and S are antagonistic processes, specifically that C would lead to increasing regularity of tree locations and S would result in clustering. Our simulation results confirmed that in the long run intertree distances decreased and canopy gap size increased when superorganisms were encouraged to form. At the same time, the overlap and packing of tree crowns increased. The long-term effect of crown plasticity increased the regularity of tree locations; however, this effect was much weaker than that of superorganism formation. As a result, gap patterns remained more or less unaffected by crown plasticity. In scenario C1S1, both processes interestingly interacted in such a way that crown plasticity even increased the effect of superorganism formation. Our simulation results are likely to prove helpful in recognizing patterns of facilitation with ongoing climate change.

摘要

迄今为止，为了直接投影遥感数据而构建的空间显式树模型很少。为了填补这一空白，我们引入了CanopyShotNoise模型的原型，这是一种基于个体的模型，专为投影机载激光扫描 (ALS) 数据而设计。鉴于 ALS 数据的性质，该模型侧重于森林生态系统中单个树木冠层的动态，即空间树木相互作用以及由此产生的生长、出生和死亡过程。在本研究中，CanopyShotNoise用于分析冠可塑性(C) 和超有机体形成过程的长期影响(S) 关于可能在持续气候变化中发挥重要作用的空间树冠模式。我们设计了一个复制的计算机实验，涉及四个场景 C0S0、C1S0、C0S1 和 C1S1，其中 0 和 1 分别表示前面的过程被关闭和打开。我们假设 C 和 S 是对抗过程，特别是 C 会导致树位置的规律性增加，而 S 会导致聚类。我们的模拟结果证实，从长远来看，当鼓励形成超有机体时，树间距离会减少，树冠间隙大小会增加。同时，树冠的重叠和堆积增加。树冠可塑性的长期作用增加了树位的规律性；然而，这种影响比超有机体形成要弱得多。因此，间隙模式或多或少不受牙冠可塑性的影响。在场景 C1S1 中，两个过程有趣地相互作用，以至于冠可塑性甚至增加了超有机体形成的影响。我们的模拟结果可能有助于识别持续气候变化的促进模式。