Kelemen Szabolcs, Józsa Máté, Hartel Tibor, Csóka György, Néda Zoltán
Faculty of Physics, Babeş-Bolyai University, Cluj-Napoca, 400347, Romania.
Faculty of Environmental Science and Engineering, Babeş-Bolyai University, Cluj-Napoca, 400294, Romania.
Sci Rep. 2024 Jan 12;14(1):1168. doi: 10.1038/s41598-024-51553-2.
The diameter distribution of a given species of deciduous trees is well approximated by a Gamma distribution. Here we give new experimental evidence for this conjecture by analyzing deciduous tree size data in mature semi-natural forest and ancient, traditionally managed wood-pasture from Central Europe. These distribution functions collapse on a universal shape if the tree sizes are normalized to the mean value in the considered sample. A new evolutionary master equation is used to model the observed distribution. The model incorporates four ecological processes: tree growth, mortality, recruitment, and diversification. Utilizing simple and realistic kernel functions describing the first three, along with an assumed multiplicative dilution due to diversification, the stationary solution of the master equation yields the experimentally observed Gamma distribution. The model as it is formulated allows an analytically compact solution and has only two fitting parameters whose values are consistent with the experimental data related to these processes. We found that the equilibrium size distribution of tree species with different ecology, originating from two contrastingly different semi-natural ecosystem types can be accurately described by a single dynamical mean-field model.
某一特定种类落叶树的直径分布可以很好地用伽马分布来近似。在此，我们通过分析中欧成熟半天然森林以及古老的、传统管理的林牧地中的落叶树大小数据，为这一猜想提供了新的实验证据。如果将树的大小归一化为所考虑样本中的平均值，这些分布函数会呈现出一种通用的形状。一个新的演化主方程被用于对观测到的分布进行建模。该模型纳入了四个生态过程：树木生长、死亡、补充和多样化。利用描述前三个过程的简单且现实的核函数，以及由于多样化而假定的乘法稀释，主方程的稳态解产生了实验观测到的伽马分布。所构建的模型允许有一个解析紧凑的解，并且只有两个拟合参数，其值与与这些过程相关的实验数据一致。我们发现，源自两种截然不同的半天然生态系统类型、具有不同生态特征的树种的平衡大小分布，可以用一个单一的动态平均场模型准确描述。
