There’s more to rainforest conservation than lush, hot tropical rainforests. Research by the Technical University of Munich reveals cool Alpine forests will also suffer if there are more frequent droughts and torrential rain. Apparently the glorious mountain forests of the Bavarian Alps have seen a ‘significant reduction’ in topsoil organic matter over the last thirty years, and the study’s author recommends increasing the amount of soil humus to safeguard mountainous forests for the future.
Humus is vital for all sorts of reasons
Good stocks of humus are vital for soil fertility. They also support a good water balance and soil nutrient supplies. The thing is, carbon bound up with soil in cooler mountain regions reacts strongly to warmer weather caused by climate change, released in huge amounts by micro-organisms. Eventually the soil loses its capacity to store carbon altogether.
Humus reduced to a poor state over a very short time
The new study looks at changes in humus stocks in Alpine soil, based on data from 35 mountain forests and high altitude pastures going back 30 years. And it looks like there’s been a dramatic, rapid and statistically significant humus loss in the mountain forest soils studied. The topsoil organic matter stock in the Bavarian Alps declined by an average of 14% and limestone and dolomite-based soils suffered the most, losing just under a third of their humus.
Warming Alpine climate dates back to the ’70s
Weather stations have recorded climate change in the area since the 1970s and the changes have been observable for the past century, especially in the badly-affected Berchtesgaden region where the average temperature rise has been ‘drastic’ through the summer months. In contrast there’s been very little humus loss in mountain pasture soils, but they’re always less humus-rich than nearby forest soils anyway.
What can be done?
The authors of the study recommend humus-promoting forest management to mitigate the effect as the climate continues to warm and we see more extreme weather. A healthy humus layer helps store water to nourish trees and Alpine flora, and also help reduce floods. To keep things working as they should, proactive humus restoration is essential.