Researchers at the Universidad Politecnica de Madrid suggest the use of dendroecology, the dating of past events through study of tree ring growth, to enhance the management and conservation of the Pinus Nigra within the centre of the Iberian Peninsula.
A study carried out in the pine forest of Navalacruz (Avila) has been used as a pioneer to prove the potential application of the dendroecology to understand the origin, forest dynamics, local variability, the relationship with the weather and the anthropogenic disturbances in relict forest. The research, headed by a researcher at the E.U. Forestry Engineering of the UPM, has proposed a series of measure focused on increasing the protection of this area, which is an exceptional biodiversity stronghold.
Pinus nigra is a species of pine that is only found in circum Mediterranean territories; it is subdivided in various isolated populations and has different features (subspecies) depending on the area. The subspecies salzmannii, commonly found in the eastern and the centre of the Iberian Peninsula, southern France and northwest Africa, occupy the most occidental position. The persistence of long-lived species Pinus nigra salzmannii in Spain, achieving even a millennium in some cases, as well as their sensitivity to climate change have attracted researchers attention. Although numerous studies have been published in the dendroecology field (Science that studies the ring growth compared to other environmental factors) so far, these types of research had not been related to conservation for biodiversity and genetic resources.
The study1 used dendroecology methods to analyze the relict pine in Navalacruz, which is located on the northern North Slope of the Sierra de los Gredos and constitutes a fascinating forest genetic resource at risk because of frequent forest fire around the area.
The interpretation of dendroecology and palaeobiogeographic data has allowed researchers to prove that this relatively young pine forest is a relict of forests wider than in the past coated the area. In addition, among other aspects, this study has detected a high variety and numerous quasi-periodic perturbations of growth (alternating between suppression and release) which indicate there are cycles of varying intensity in the exploitation of wood from this forest.
The pine forest of Navalacruz constitutes an example of this type of forest at low altitude which could provide Sierra de los Gredos with valuable genetic resources in a future scenario of global warming.
For this reason, it is essential to take management actions that can increase de protection of this area, as suppression of foreign plantations with other subspecies what would prevent genetic contamination. The study results suggest that local conditions are very important for the growth and regeneration and it is desirable a multivariate approach to its conservation.
In some cases would be convenient to remove shrubs and herbaceous perennials to promote regeneration and in other cases the selective thinning can increase the regeneration and to promote increased tree growth.
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