Effect of stand structure on Stone pine (Pinus pinea L.) regeneration dynamics

Abstract

Natural regeneration of stone pine (Pinus pinea L.) in the Northern Plateau of Spain is fraught with problems and, consequently, difficult to attain. In this study, we start by describing the spatial structure of one even-aged and one uneven multi-aged stand as a first step towards understanding the processes that produce the spatial patterns and, in turn, provide managers with information that could help to enhance regeneration. All trees were mapped and located through their xy coordinates and two perpendicular crown diameter measurements were recorded for each tree in addition to other structural variables. A grid-based approach, in which crowns were projected on a grid, was then used to characterize the spatial pattern and this was compared with the conventional point pattern analysis. This allowed us to take into account variations in crown size and shape. Regeneration was found to be clumped in both stands and the spatial association with stems varied among the age classes considered. Results from the crown pattern analysis differed from those obtained using the traditional point pattern analysis, especially in the older age classes, where crowns were larger and had a greater influence on regeneration. Our results suggest that where large variations in crown dimensions exist, the use of this method can help us to avoid misinterpretations of the results and provide further insight into the processes that drive natural regeneration. © Institute of Chartered Foresters, 2008. All rights reserved.