Structural diversity of the forest
High structural diversity promotes biodiversity by creating a variety of habitats for different species. Structural diversity and structural attributes are therefore important parameters of the ecological quality and the adaptability of forests to changes. A forest with a multi-layered or graduated structure is more resilient to environmental changes and disturbances, such as storms or insect infestations, because it possesses a greater capacity for adaptation and regeneration.
good
positive
- Database
- National forest inventory (NFI)
The structural diversity according to the NFI is a synthetic indicator for evaluating a forest stand as a habitat. Structurally rich forest stands are an important basis for high species diversity. When looking at individual characteristics, the (regional) developments have sometimes been different; for example, an increase in deadwood and branch piles, while at the same time an unfavorable development in the degree of damage to the stand. Overall, the structural diversity in Swiss forests is in good condition.
In their vertical structure, a good third of the stands nationwide are single-layered. Due to various factors such as altitude, site conditions and historical management, all the trees have approximately the same age and dimension in these forests. Particularly many single-layered stands are found on the southern side of the Alps, the Pre-Alps and in the Alps. Their proportion has further increased in the last decade. Uniform forests without any regeneration are unfavorable in the face of increasing disturbances due to climate change. This applies especially to protective forests.
Datas are provided by aerial images, the continuous sample survey carried out in forests and subsequent modelling. Evaluation unit: accessible forest without brushwood. Network: 1.4 km network (in NFI5: 1.4 km network, sub-networks 1-5).
Structural diversity of the stand (composite indicator): Value of the forest stand as a habitat, derived from NFI characteristics such as development stage, canopy closure, stand structure, proportion of large trees, degree of stand damage, presence of forest or stand edges, occurrence and type of gaps in the stand, coverage of the herb layer, coverage of berry shrubs, as well as the presence of stumps, lying deadwood, standing dead trees, and branch piles. Data on structural diversity of the stand are only available from NFI2 onwards.
Stand structure: vertical structure (layering) of a tree stand, defined by the canopy cover degrees of the upper, middle, and lower layers.
| Targeted trend | Initial value | Final value | Variation in % | Observed trend | Assessment |
|---|---|---|---|---|---|
| Growth | 1993/95 (NFI2) | 2018/22 (NFI5) | 40.54% | Growth | positive |
| Basis: (1) Structural diversity - high | |||||
Further information
