Forest Fragmentation in Bavaria: A First-Time Quantitative Analysis Based on Earth Observation Data

Anthropogenic and climatic pressures can transform contiguous forests into smaller, less connected fragments. Forest biodiversity and ecosystem functioning can further-more be compromised or enhanced. We present a descriptive analysis of recent forest fragmentation in Bavaria, the largest federal state in Germany. We calculated 22 metrics of fragmentation on forest polygons, aggregated within administrative units and with respect to both elevation and aspect orientation. Using a forest mask from September 2024, we found 2.384 million hectares of forest across Bavaria distributed amongst 83,253 forest polygons 0.1 hectare and larger. XS patches (< 25 ha), outnumber all other size classes (25-160 ha, 160-789 ha, 789-3,594 ha, and 3,594-48,703 ha) by nearly 13 to 1. Edge zones, where microclimatic effects may distinguish an area up to 100m from the forest perimeter, accounted for more than 1.68 million hectares, leaving less than 703,000 remaining hectares as core forest. Although south-facing slopes dominated the state, the highest forest cover (~36%) was found on least abundant east-oriented slopes. Most of the area is located at 400-600 m.a.s.l. with around 30% of this area covered by forests, however, XL forest patches (> 3,594 ha) dominated higher elevations, covering 30-60% of land surface area between 600-1400 m.a.s.l. The distribution of the largest patches follows the higher terrain and corresponds well to protected areas.