资源环境科技发展态势分析平台

A deep understanding of vertical and horizontal structure of old-growth Norway spruce mixed forests is critical for anticipating management outcomes and developing appropriate strategies for sustaining these complex forests. In most cases, the forest structure is assessed at stand level; however, the outcomes and impacts of natural disturbances (e.g., competition-induced mortality) and human interventions on development of spruce mixed forests occur across a landscape. We compared spatial interactions and size inequality on 148 plots randomly distributed across spruce-dominated stands in the national park (NP), protected stands (PS), and managed stands (MS) of the Bialowieta Forest (BF) in north-eastern Poland. Spatial pattern analyses and Gini coefficient (GC) were used to describe the conditions of spruce mixed stands with different management strategies. Scale-dependent density of conspecifics and heterospecifics around spruce individuals, inhibition between the dbh of spruce and neighbouring trees, negative correlation between neighbourhood density and spruce dbh, and size inequality of spruce were the structural properties negatively influenced by human activities in spruce mixed stands and highlight the lasting effect of management on these structural conditions. In contrast, there was no evidence of significant difference between some structural properties, including spruce mean dbh and mean GC values of NP, PS, and MS. The vertical and horizontal structure observed across three parts of the BF reveal the importance of having variation in spatial distribution and size irregularity across PS and MS to approximate these attributes in NP. In addition, the lower dbh of spruce individuals having a con specific neighbour compared to nearby heterospecifics due to intense intraspecific competition documented in this and other comparisons between pure and mixed spruce forests argues for an increased emphasis on mixture of spruce and other species if the sustainability of spruce is considered as a management objective.