Improving the adaptation capacity in reforestations in the Valencian Community

In the Valencian Community, reforestations with Pinus pinaster were carried out in large areas in the 1970s. The lack of proper maintenance, the extensive reforested area, and the high homogeneity of the stands make them particularly vulnerable to climate change. The purpose of this action is to promote the adaptation capacity and resilience of these reforested stands.

The measures will consist of applying “close-to-nature forest management” aimed at promoting attributes typical of forest maturity by modifying the structure of the stands to promote natural regeneration, increase species diversity, and reduce competition.

Implemented actions:

Participatory process

With the aim of involving forest owners, an informative session was held, where the forests of Mairana, owned by the Generalitat, the forests of Las Lomas, belonging to the Barracas City Council, and four private owners were successfully engaged.

Design of adaptation measures

The application of the vulnerability index (Action C1) allowed the identification of the main objectives, which include diversifying the structure, diameter classes, and species composition. Following the criteria generated in Action C2, selective thinning was designed for these plots.

Selective thinning involves reducing tree density in designated areas to decrease linearity and promote natural regeneration. This reduction in tree density also reduces competition for water, creating a forest stand that is more resilient to drought. Within each thinned area, all broadleaf species (holm oak and oak) are preserved, and, preferably, Pinus nigra subsp. nigra or austriaca is selectively thinned while respecting other native pine species (Pinus pinaster, Pinus sylvestris, and Pinus nigra subsp. salzmannii).

During tree marking, all existing microhabitats or trees capable of hosting these microhabitats, such as bifurcated trees, are preserved. The existing deadwood is all retained.

Example of Pinus pinaster reforestation. Current state.

Example of Pinus pinaster reforestation after a clearing.

Example of Pinus pinaster reforestation following the actions of the project.

Implementation of the measures

Location of the thinned areas: A number of thinned areas per plot is established based on the dominant height and the projected final density. Thinned areas are distributed randomly, avoiding round shapes. Thinned areas cover 40% of the plot.

Marking of trees: In the field, 50-60 trees are selected in small thinned areas (radius 1.5 times the dominant height) and 100-120 in large thinned areas (radius 2.5 times the dominant height).

Felling of marked trees: Once marked, the selected trees are cut down by specialised personnel.

Extraction of felled trees using a forestry forwarder and support chainsaw operator. The wood is stacked and later chipped for sale and processing.

Example of thinned area distribution in a plot in the Mairana forest.