BayCEER Workshop 2025

The path to tranquility: Recovery of forest soils after disturbance

Disturbance of forests (e.g. via wind, infestation, harvesting, fire, etc.) will be a more prominent occurrence in temperate climate forests due to climate change. Since the effects of disturbances onto forest vegetation have been the major focus in research and soils are often less in the focus, this study aims to gain a better understanding how soils are recovering after canopy opening events. Therefore a chronosequence of organic and mineral horizons were selected in different forests types (spruce, beech) as well as under different patterns on the site if present (grass, shrub, tree). Organic carbon, nitrogen, oxygen and respiration were analyzed. We hoypthesized that

1. Disturbances add more organic carbon to the soil leading to a primary carbon loss and higher nutrient availability due to higher microbial activity. 2. Temperature-sensitivity of soil respiration (Q10) is higher on soil under grass, shrubs or beech compared to spruce as the substrate quality is favourable for microbes. 3. Forest recovery under spruce leads to less nutrient availability and more carbon storage due to the lower quality of the spruce derived litter compared to beech. 4.Water holding capacity of the different sites is highly dependent on carbon content of the Oe and Oa-A-horizon.

Effects of the disturbance are only visible in the Oa-A horizon where the carbon content decreases in the first 18 years before it starts to rise again. Carbon content is influencing the water holding capacity significantly with higher carbon content leading to a higher water holding capacity. Coniferous sites disturbed in the year 2007 had the highest microbial activity in the Oe-horizon especially under grass and young trees.