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

08.09.2004


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:
http://www.basqueresearch.com
http://www.elhuyar.com

More articles from Agricultural and Forestry Science:

nachricht Ammonium nitrogen input increases the synthesis of anticarcinogenic compounds in broccoli
26.04.2017 | University of the Basque Country

nachricht New data unearths pesticide peril in beehives
21.04.2017 | Cornell University

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: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Fighting drug resistant tuberculosis – InfectoGnostics meets MYCO-NET² partners in Peru

28.04.2017 | Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

 
Latest News

Wireless power can drive tiny electronic devices in the GI tract

28.04.2017 | Medical Engineering

Ice cave in Transylvania yields window into region's past

28.04.2017 | Earth Sciences

Nose2Brain – Better Therapy for Multiple Sclerosis

28.04.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>