Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


A computer simulation tool that predicts the influence of forest clearings on soil fertility


The process of clearing consists of cutting down trees in such a way that those remaining have more resources and can grow more. The question was if too many had been cut down, with the concomitant removal of nutrients, and the manner, therefore, in which this process might affect long-term soil fertility.

A PhD thesis presented in the Public University of Navarre specifically analysed the internal cycle of nutrients in two wooded areas in Pinus sylvestris forests, this species, together with the beech, being the most common tree in the Navarre mountains, especially in the Pyrenees. The areas chosen were in Aspurz and Garde, locations situated at different altitudes.

In the first stage, the above-ground biomass of the wood was measured before and after the clearing is carried out, i.e. we analysed the amount of wood, leaves and bark and each one of the nutrients (such as nitrogen and phosphorous) that existed in the wood. Then the biomass of the dry leaves, branches, etc. of the trees in question fallen onto the floor is measured in order to assess what nutrients returned naturally from the trees to the soil and which, therefore, would be natural fertiliser. The results concluded that the clearings reduced both the above-ground biomass as well as the mineral mass, although no differences in this drop were registered between different intensities of clearings.

In the second study, we start calculating the removal of nutrients from green leaves before they dry out, given that trees have a mechanism to reduce this nutrient loss and increase efficiency in their use. These parameters were not observed to have been influenced by the clearings.

The third experiment consisted of analysing the loss of weight and the chemical composition of the dead leaves. We analysed how this layer of fallen leaves deteriorated, how it breaks up and reconstitutes itself on the ground. In this way we could observe that both woods underwent a slowing down of this process after the clearings took place.

The fourth trial studied the respiration of the soil and its chemical composition and, in this way, the cycle is closed in which the tree first gathers the nutrients to be used to generate biomass, part of this biomass falls, degrades and, once more, reconstitutes itself in the soil to be reused by the tree. We found that respiration was greater in the location at higher temperatures and only in this wood was there detected a passing increase in respiration after the clearings had taken place. Neither did the clearings affect the chemical composition of the soil.

Subsequent to these studies, in the last stage of the thesis, we evaluated the changes in the reserves of nutrients. To this end, we created a computer tool that is a simulation model of the circulation of nutrients based on balances of masses. This has enabled us to predict what will happen to these trees in 60 years time.

A prediction that provides a number of possibilities in this process. It not only tells us that we should carry out clearings, but how often they should be carried out, how many trees should be cut down and whether the whole tree should be cut down or just the trunk or whether the branches and leaves should be left.

Acceptable limit

In any case, it can be affirmed that the management of forest clearings currently comes close to the acceptable limit, although we have to have more data to assess if the mountain is losing fertility. But, in order not to reduce the reserves of nutrients of a forest, the same form of clearings should not be applied to different zones without a prior evaluation of the consequences in each particular case, given that the effect of the clearings on internal cycle of nutrients largely depends on the features of each wooded area.

Garazi Andonegi | alfa
Further information:

More articles from Agricultural and Forestry Science:

nachricht Unique communication strategy discovered in stem cell pathway controlling plant growth
23.03.2018 | Cold Spring Harbor Laboratory

nachricht “How trees coexist” – new findings from biodiversity research published in Nature Communications
22.03.2018 | Technische Universität Dresden

All articles from Agricultural and Forestry Science >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Space observation with radar to secure Germany's space infrastructure

Satellites in near-Earth orbit are at risk due to the steady increase in space debris. But their mission in the areas of telecommunications, navigation or weather forecasts is essential for society. Fraunhofer FHR therefore develops radar-based systems which allow the detection, tracking and cataloging of even the smallest particles of debris. Satellite operators who have access to our data are in a better position to plan evasive maneuvers and prevent destructive collisions. From April, 25-29 2018, Fraunhofer FHR and its partners will exhibit the complementary radar systems TIRA and GESTRA as well as the latest radar techniques for space observation across three stands at the ILA Berlin.

The "traffic situation" in space is very tense: the Earth is currently being orbited not only by countless satellites but also by a large volume of space...

Im Focus: Researchers Discover New Anti-Cancer Protein

An international team of researchers has discovered a new anti-cancer protein. The protein, called LHPP, prevents the uncontrolled proliferation of cancer cells in the liver. The researchers led by Prof. Michael N. Hall from the Biozentrum, University of Basel, report in “Nature” that LHPP can also serve as a biomarker for the diagnosis and prognosis of liver cancer.

The incidence of liver cancer, also known as hepatocellular carcinoma, is steadily increasing. In the last twenty years, the number of cases has almost doubled...

Im Focus: Researchers at Fraunhofer monitor re-entry of Chinese space station Tiangong-1

In just a few weeks from now, the Chinese space station Tiangong-1 will re-enter the Earth's atmosphere where it will to a large extent burn up. It is possible that some debris will reach the Earth's surface. Tiangong-1 is orbiting the Earth uncontrolled at a speed of approx. 29,000 km/h.Currently the prognosis relating to the time of impact currently lies within a window of several days. The scientists at Fraunhofer FHR have already been monitoring Tiangong-1 for a number of weeks with their TIRA system, one of the most powerful space observation radars in the world, with a view to supporting the German Space Situational Awareness Center and the ESA with their re-entry forecasts.

Following the loss of radio contact with Tiangong-1 in 2016 and due to the low orbital height, it is now inevitable that the Chinese space station will...

Im Focus: Alliance „OLED Licht Forum“ – Key partner for OLED lighting solutions

Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP, provider of research and development services for OLED lighting solutions, announces the founding of the “OLED Licht Forum” and presents latest OLED design and lighting solutions during light+building, from March 18th – 23rd, 2018 in Frankfurt a.M./Germany, at booth no. F91 in Hall 4.0.

They are united in their passion for OLED (organic light emitting diodes) lighting with all of its unique facets and application possibilities. Thus experts in...

Im Focus: Mars' oceans formed early, possibly aided by massive volcanic eruptions

Oceans formed before Tharsis and evolved together, shaping climate history of Mars

A new scenario seeking to explain how Mars' putative oceans came and went over the last 4 billion years implies that the oceans formed several hundred million...

All Focus news of the innovation-report >>>



Industry & Economy
Event News

New solar solutions for sustainable buildings and cities

23.03.2018 | Event News

Virtual reality conference comes to Reutlingen

19.03.2018 | Event News

Ultrafast Wireless and Chip Design at the DATE Conference in Dresden

16.03.2018 | Event News

Latest News

For graphite pellets, just add elbow grease

23.03.2018 | Materials Sciences

Unique communication strategy discovered in stem cell pathway controlling plant growth

23.03.2018 | Agricultural and Forestry Science

Sharpening the X-ray view of the nanocosm

23.03.2018 | Physics and Astronomy

Science & Research
Overview of more VideoLinks >>>