Resistance tests of native pine to drought
The Forestry Association of Galicia has just participated together with three researchers from the French National Research Institute for Agriculture, Food and Environment (National Institute for Agricultural Research) in the collection of samples of the country's pine (Pine maritime) to measure its resistance to drying.
This study is part of the project. FORMANRISK (Forest management and natural risks) within the framework of the INTERREG SUDOE programme of the European Union, in which the Forestry Association of Galicia participates together with INRAE, the Mediterranean Institute of Cork, the Aragonese Society for Agro-environmental Management (SARGA), the Catalan Centre for Forest Science and Technology (CTFC), a University of Trás-os-Montes and Alto Douro (UTAD), a Provincial Council of Ávila and the company GISTREE, led by National Forestry Office (ONF).
Between 20 and 23 July, three researchers from INRAE and two people from the Galician Forestry Association collected samples in the community woodlands of Santa María de Oín (Rois), San Vicente do Mar (O Grove) and Cabeiras (Arbo) to measure their drought resistance. The measurements were taken at 6 a.m. and 3 p.m., at the times of peak and minimum temperature.
Using the Cavitron equipment, the needles of the pine chosen for the test are subjected to severe depression, simulating a very intense drought until the water column flowing through the plant tissue's vessels breaks, causing the sap flow to collapse. When this happens, the tree dies, as the roots can no longer supply water to the leaves when they lose it through evaporation. With these measurements, the maximum depression at which a leaf cannot withstand is recorded for each selected tree, when capillary action breaks down and air bubbles appear in the vascular tissues, in the so-called process of cavitation or embolism.
During this July, this expedition is touring south-west Europe with a mobile laboratory in a van, and with the help of local technicians from the project partners, it is studying whether different pine provenance lines exhibit distinct resistance behaviours to drought. The aim is to be able to select which provenance lines are best prepared for the severe droughts predicted in the future as a consequence of climate change.
