The soils of the Basque forests could absorb about double the quantity of carbon with a change in forest management and thus contribute to reducing the presence of this gas in the air and, in turn, ameliorate the problem of global warming. This is the main conclusion of the research carried out by the Basque Institute of Agricultural Research and Development, Neiker-Tecnalia, in which more than a thousand samples of soil belonging to representative forest masses in Euskadi were studied - eucalyptus, pinus radiata, Douglas fir and beech. This research falls within the remit of the activities of this technological centre aimed at enhancing the activity and competitiveness of the Basque forestry sector.
Soils are the principal deposit of organic carbon in the biosphere, and thus constitute a key element in the flow of atmospheric carbon between the atmosphere and the Earth’s crust. At present, forest soils in temperate climates are a fundamental drainage system which absorbs more carbon from the atmosphere – through photosynthesis – than the quantity emitted through respiration. Nevertheless, the new environmental conditions derived from climate change could change this situation. This is why Neiker-Tecnalia Technology Centre has undertaken research in order to determine the existence of the carbon content in the soils of Basque forests and puts forward measures to increase it.
From the Neiker-Tecnalia research it was concluded that all the forest plots studied were below 40% of their total potential for carbon storage capacity and all the eucalyptus forests below 30%. Thus, forest management in the Basque Country has a significant margin for absorption capacity of carbon in forests. In order to achieve this, specialists from the Technology Centre propose the rational and appropriate use of machinery during the tasks of felling, clearance and terrain preparation. Moreover, this machinery has to be adapted to the orography and terrain of the Basque Country.
The specialists also call for including the aspect of improvement in carbon stocks in the soil when management measures aimed at taking advantage of energy are proposed when working with leftover bark, normally used for creating biomass.
Neiker-Tecnalia also holds that the rates of carbon storage in forest soils should be able to be monitored and should be quantified, in order to objectively evaluate the effect of changes in forestry management and thereby comply with the Kyoto Protocol and the European Directive on Good Practices for Land-Use Change and Forestry.
Representative samples of the Basque forestry mass
Neiker-Tecnalia researchers analysed a total of 1,180 samples of forest soils for the PEFC forestry certification management plans between 2005 and 2010, all representative of the forest mass in the Atlantic region of the Autonomous Community of the Basque Country. The results pointed to the fact that the current stocks of carbon in the plots studied vary between 57 and 100 tons of carbon per hectare down to the first 25 cm of depth, values which coincide with a recent report published on this matter by the European Commission. However, these values are far from the potential of the carbon sequestration of these soils.
Eucalyptus forest soils present the lowest values for carbon storage; in concrete, values less than 25% of their total potential storage capacity for carbon. The plantations of pinus radiata are between 22% and 28% of their storage capacity, while beech woods and plantations of Douglas fir register between 30% and 40% of their total potential for carbon fixing.
As regards the volume of carbon stored by Basque forest soils Eucalyptus forests present an average content of between 67 and 73 tons of this gas per hectare. The plantations of pinus radiata retain between 67 and 74 tons, while beech woods and Douglas fir store between 80 and 82 tons per hectare.
The low percentages in potential of carbon fixing may be due to old forestry policies and practices, and which did not include concepts of survival and sustainability, together with the abusive use of other forestry products (firewood, charcoal, humus and bushes used as bedding for livestock, etc.). The current forestry sector has the opportunity to reverse this trend and begin to consider the absorption of carbon as a target within its management plans.
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