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 Climate change, population growth may lead to open ocean aquaculture
05.10.2017 | Oregon State University

nachricht New machine evaluates soybean at harvest for quality
04.10.2017 | University of Illinois College of Agricultural, Consumer and Environmental Sciences

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: Neutron star merger directly observed for the first time

University of Maryland researchers contribute to historic detection of gravitational waves and light created by event

On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...

Im Focus: Breaking: the first light from two neutron stars merging

Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.

Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....

Im Focus: Smart sensors for efficient processes

Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).

When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...

Im Focus: Cold molecules on collision course

Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.

How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...

Im Focus: Shrinking the proton again!

Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.

It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ASEAN Member States discuss the future role of renewable energy

17.10.2017 | Event News

World Health Summit 2017: International experts set the course for the future of Global Health

10.10.2017 | Event News

Climate Engineering Conference 2017 Opens in Berlin

10.10.2017 | Event News

 
Latest News

Osaka university researchers make the slipperiest surfaces adhesive

18.10.2017 | Materials Sciences

Space radiation won't stop NASA's human exploration

18.10.2017 | Physics and Astronomy

Los Alamos researchers and supercomputers help interpret the latest LIGO findings

18.10.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>