Skip to main content
SLU publication database (SLUpub)

Abstract

While homogeneity of forest stands was previously sought to simplify forest management planning, structurally rich stands are increasingly encouraged and implemented in contemporary forest management. One reason for this reversal is that structuring may promote forest stability and resilience as well as the provision of ecosystem services. However, the effect of structure on forest growth is not yet fully understood. In contrast, simple density growth relationships are commonly used for modelling, forest planning, and as a background for forest man-agement decisions without taking structure into account. Using the example of long-term Norway spruce (Picea abies (L.) H. Karst) stands covering a wide range of structures, densities, and site conditions, we investigated how stand structure modulates tree and forest stand growth and what mechanisms are behind this modulation. First, we show that under otherwise identical conditions, tree size variation increases the crown occupancy of the 3-dimensional space owing to the wider vertical distribution of tree crowns. We furthermore demonstrate that the occupancy of structurally diverse forests increases relative to the occupancy of homogenous forests with increasing stand density. Second, we found that, all other conditions being equal, stand growth increases asymptotically with increasing tree size variation; this applies to both managed and unmanaged forests although the level and rate of increase is higher in dense, un-thinned forests than in thinned forests. Third, we reveal the interdependency between size distribution and size-growth, demonstrating that structural diversity increases the growth efficiency of large trees in dense forests but increases the efficiency of smaller trees in sparsely stocked forests. Ensembles of trees with different sizes and efficiencies can make the best possible use of the growing space and resources and produce maximum stand growth. We discuss how previously contradictory views on the relationships between density and growth, density and symmetry of competition, and size and growth of trees become consistent when structural diversity is taken into account. Based on these findings, we also evaluate how growth responds to structurally oriented high thinning compared with homogenizing low thinning.

Keywords

Density-growth relationship; Size-growth relationship; Structural diversity; Thinning effects; Vertical stand structure; Growth partitioning, growth efficiency

Published in

Forest Ecology and Management
2026, volume: 611, article number: 123699
Publisher: ELSEVIER

SLU Authors

UKÄ Subject classification

Forest Science

Publication identifier

  • DOI: https://doi.org/10.1016/j.foreco.2026.123699

Permanent link to this page (URI)

https://res.slu.se/id/publ/146679