Structure and growth of mixed Scots pine/European beech stands compared with pure stands analyzed along an ecological gradient through Europe

混交林的新特性和过度屈服的原因尚不清楚，但对了解和预测混交林动态以及设计资源高效生产系统具有重要意义。这个项目将重点放在苏格兰松和欧洲山毛榉的混合物上。它们互补的生态特性可能导致目前的超产，并可能变得更加稳定，从而在未来气候变化下具有相关性。我们将以一个独特的数据集为基础，该数据集由30个成熟的、充分储存的苏格兰松和欧洲山毛榉的三胞胎混合和纯林分组成，这些林分位于整个欧洲的生态梯度上，这些林分已经建立、测量并通过增量取芯进行采样。申请人作为成本行动eumixfor1206的副主席组织设立了这些三人组，目的是使混合林场研究标准化和协调一致。对于这个拟议的项目，现有的树木数据、增量核心和林分数据将通过光和水条件的测量来补充，以便回答以下问题。在林分水平上，物种混合如何影响生产力和最大林分密度承载能力。任何超产和最大林分密度的增加都表明竞争和促进同时发生的积极净效应。为了更好地理解资源供给、捕获和利用效率对混合效应的影响，我们其次考察了混合效应如何沿着生态梯度从营养贫乏和干燥地向肥沃和潮湿地变化。基于回顾性的树木年轮数据，我们将分析主要的年度天气条件对混合效应的时间变异性和依赖性。-通过分析单个树木的结构、生长和大小分布，我们可以追踪从树木到林分水平的混合效应，并揭示树木的哪个子集，即哪个层次层导致混合林分与纯林分的过度或低产。基于额外的光和土壤湿度测量，我们将质疑混合效应是如何通过光和水的供应、捕获和利用效率之间的相互作用来调节的。考虑到气候变化和从纯针叶树到针叶树与阔叶树混合的持续过渡，苏格兰松和欧洲山毛榉的混合得到了更多的关注。揭示时空间的相互作用、资源条件的依赖性和生产力方面的结果可能有助于更好地理解、建模和设计资源高效生产系统。

Emerging properties in species mixtures and causes of overyielding are hardly clarified, but important for the understanding and the prediction of mixed stand dynamics and for the designing of resource efficient production systems. This project would be focused on mixtures of Scots pine and European beech. Their complementary ecological traits might cause overyielding at present and may become even more stabilizing and thereby relevant in future under a changed climate. We would base the project on a unique dataset of 30 triplets of mature and fully stocked mixed and pure stands of Scots pine and European beech located along an ecological gradient through Europe, which are already established, measured, and sampled by increment coring. The applicant organized the establishment of those triplets acting as vice chair of COST action EuMIXFOR 1206 for the purpose of standardization and harmonization of mixed stand research. For this proposed project the already available tree data, increment cores, and stand data will be complemented by measurements of light and water conditions so that the following questions can be answered.-How does species mixing affect productivity and maximum stand density -carrying capacity- at the stand level. Any overyielding and increase of maximum stand density would indicate a positive net effect of simultaneously occurring competition and facilitation. -In order to better understand the modification of the mixing effects by supply, capture and use efficiency of resources, we secondly scrutinize how the mixing effect changes along an ecological gradient from nutrient poor and dry sites to fertile and moist sites. -Based on the retrospective tree ring data we will analyse the temporal variability and dependency of mixing effects from the prevailing annual weather conditions. -By analysing individual tree structure, growth, and size distributions we can trace mixing effects from the tree to the stand level and reveal which subset of trees, i.e., which hierarchical stratum contributes to over- or underyielding of mixed versus pure stands. -Based on additional light and soil moisture measurements we will question how the mixing effects are modulated by the interplay between light and water supply, capture, and use efficiency.Mixtures of Scots pine and European beech get more attention in view of climate change and the ongoing transition from pure conifer stands to mixtures of conifers with broadleaved trees. Revelation of the spatial and temporal inter-specific interactions, there dependency of resource conditions and there outcomes in terms of productivity may contribute to better understanding, modelling and designing of resource efficient production systems.