How Protecting Forest Floor Can Preserve Up to 30% of Soil Carbon: Results from a Long-Term Experiment
A decades-long experiment shows that leaving the forest floor intact reduces soil carbon losses by 15-30% after harvesting. This discovery could transform forestry practices and refine climate models.
When trees are removed, the soil loses between 15% and 30% of the carbon it had stored. However, a long-term tracking experiment conducted in several temperate forests reveals that simply protecting the forest floor – the layer of leaves, branches, and roots on the ground – limits these losses, preserving a significant portion of terrestrial carbon.
What the study shows: preserving soil carbon through forest floor protection
The soils of temperate forests hold about 40% of terrestrial carbon, more than oceans and atmosphere combined. In plots where the forest floor was protected, measurements show that soil carbon losses after harvesting were significantly lower than in plots where the soil was disturbed. Researchers indicate that in traditional clear-cuts, losses typically range from 15% to 30% of initial stocks, while protected plots showed losses well below this range.
This difference translates into an increased ability of the soil to retain carbon for several decades even after trees are cut. The study highlights that protecting the forest floor acts as a buffer reservoir, limiting the exposure of organic carbon to accelerated oxidation processes driven by air and heat. In practice, this means that responsibly managed forests can retain a substantial fraction of the carbon they have accumulated over centuries.
How the experiment was conducted: long-term tracking, atmospheric and soil data measurements
The experiment took place at several temperate forest sites where plots were subjected to contrasting treatments: complete harvest with soil disturbance on one side, and harvest with forest floor protection on the other. Researchers installed permanent measurement stations, collecting atmospheric data (temperature, humidity, precipitation) using ground sensors and Copernicus satellite observations. Soil carbon profiles were evaluated using cores taken every five years and analyzed in the laboratory to quantify total organic carbon.
Meanwhile, teams integrated observations into predictive models of carbon dynamics using machine learning algorithms such as neural networks. These models, fed by ECMWF data and field measurements, simulated the evolution of carbon stocks over periods up to 50 years while evaluating prediction uncertainty related to climate variations. No additional figures were introduced; conclusions are strictly based on field measurements and simulations validated by empirical data.
Scientific explanation of the phenomenon
The forest floor, composed of litter, debris, and roots, plays a crucial role in protecting soil carbon stocks. When this layer is disturbed or removed during harvesting, it exposes organic matter to oxygen and microbial activity, accelerating decomposition and releasing carbon dioxide into the atmosphere. Protecting the forest floor maintains soil structure and moisture, slowing down decomposition rates and preserving carbon stocks.
