In a groundbreaking endeavor, scientists from the University of Innsbruck are delving into forgotten practices of forest use in the Alps at the beginning of the 19th century. The focus of their research is on “litter utilization,” a widespread practice involving the removal of needles, leaves, and the humus layer for use as stable bedding or fertilizer. The researchers aim to unravel the impact of this intensive forest floor use on the water balance, exploring potential consequences for modern-day ecological understanding.
The Alps’ forests underwent significant transformations in the 19th century, with the practice of litter utilization being a common thread in shaping the landscape. The removal of the top layers of soil, known as the organic layer, for agricultural purposes led to a permanent reduction in the forest’s nutrient content. Clemens Geitner from the Institute of Geography at the University of Innsbruck explains, “We believe that in the event of a flood in an area with intensive forest soil use, the condition of the forest floor and its inability to absorb heavy rain events could have played a role.”
To recreate the historical context, researchers are conducting large-scale irrigation experiments on test areas before and after litter usage. Collaborating closely with the local history museum in Fügen and relying on historical tools, the team is dedicated to providing accurate insights into the absorption capacity of the forest floor. Historical sources from around 1840, forest descriptions, and maps form the basis for selecting study areas, ensuring a comprehensive dataset.
The researchers selected four test areas – Stummerberg in the Zillertal, Söll, Ellmau, and Matrei am Brenner – for detailed analysis. Irrigation tests simulated heavy rainfall, allowing scientists to assess the forest floor’s ability to absorb water. Subsequent to the first round of tests, the forest floor was removed from the test areas, mimicking the historical practice of litter utilization. The irrigation tests were then repeated, and the data on runoff processes were evaluated and compared with untreated soil.
Clemens Geitner states, “The goal is to create a model that maps the runoff process as accurately as possible.” Preliminary results from the tests have provided intriguing insights, revealing varying effects of historical land use on surface runoff. Some areas showed no change, while others experienced increased runoff after litter usage.
As the project progresses, the research team is conducting laboratory tests on the organic soil layer and installing a network to measure soil moisture and temperature. Notably, the researchers discovered the rare emerald green earthworm near Söll during their experiments, underscoring the importance of near-natural forests.
The team is committed to deepening their understanding of the historical use of litter and its long-term effects on Tyrolean forests. By combining historical insights with cutting-edge scientific methods, the researchers aim to unlock the secrets of forest history, contributing valuable knowledge to contemporary ecological discourse. Stay tuned for further developments as the project continues to unfold.
