"At this moment, in this atmospheric river and in these storms that occurred in the previous weeks, we have a loss of 20,000 trees and in the Martinho depression we had 230,000 trees that were affected, which gives us a total of 250,000 trees affected in this space of less than a year," said the President of Parques de Sintra-Monte da Lua (PSML), João Sousa Rego.

The head of the publicly owned company that manages the historic gardens and monuments in the Serra de Sintra, speaking to Lusa after the “Resilient Sintra” meeting with property owners and associations, argued that the scale of the damage means that “the volume of actions and management model” must “change significantly” to meet the needs of the area.

Recent weather conditions

In addition to the recent depressions, Kristin, Leonardo, and Marta, Storm Martinho struck the Sintra mountain range on the night of March 19-20 of last year with heavy rain and strong winds, with gusts reaching 169 km/h at Cabo da Roca, following weeks of high precipitation levels, causing soil saturation.

In April, PSML identified, after surveys using drones and on the ground, the fall of 98,000 trees, affecting 280 hectares (ha) of the approximately 1,000 hectares of the mountain range's forest perimeter under the company's management, including 5,000 trees in woodlands and enclosed areas, especially those of Monserrate and D. Fernando II.

The Sintra City Council, for its part, estimated that 23,000 trees fell on private land in the mountain range due to Storm Martinho.

The PSML director revealed that, in the new survey, the forested area within the perimeter was the most affected, "significantly," covering "more than 80%" of the area, while "in parks and gardens the impact is relatively less," with situations that are "more controlled."

As a consequence of Storm Kristin, one hundred and fifty trees fell in the Pena and Monserrate parks and in the gardens of the National Palace of Sintra, including iconic species of the Serra da Mantiqueira mountain range.

“The time it takes to act on the territory allows us to have more data, more information to be able to be more precise in assessing the damage. And the objective of the damage assessment is to empower Parques de Sintra for reforestation,” and to develop “a new strategy for forest valorisation,” emphasised João Sousa Rego.

These storms “are becoming less frequent” and, therefore, the company's management has doubled its investment in the forest to €3.6 million this year, and is “reorganising the teams and finding the best solutions to increase technical capacity and a more resilient operating model to climate change,” he pointed out.

More native trees

“We need a mountain range with more native trees, with lower density in many cases and greater differentiation in tree types, which will not only make them more robust against harsh weather and the risk of fire, but also allow us to have a greater capacity for biodiversity development,” he argued.

In this sense, he advocated the creation of "landscape mosaics," taking advantage of "areas with large tree falls to create forest discontinuities," creating meadows and biodiversity in these areas, which also serve "to stop the spread" of fires, and the recovery of watercourses.

Controlling invasive species

Other actions include controlling invasive exotic species, planting to promote shade, preserving the "view system" in a 19th-century cultural landscape, and developing management plans for each park and forest area, with "concrete actions" and teams focused on these objectives.

For a more resilient forest, the circular economy model will enable "other types of income" and "solutions," such as the use of woody materials, forest clearings and plants, and products of forest management, such as honey.

According to Sousa Rego, increased knowledge is also achieved through "seed reserves," for the reproduction of plants and species that allow for the reinterpretation of these historical spaces while maintaining their romantic character "and uniqueness."

Removal of affected trees

The removal of the affected trees will “extend over the next three years,” it is not immediate, proceeding in areas considered “at highest risk” and, in parallel, preparing “replanting actions to stop soil loss resulting from erosion” and solutions “that reduce the risk of the reappearance of invasive exotic species.”

“This, without neglecting the preparation we have to ensure for the summer with the management of fuel breaks to reduce the risk of fire,” he concluded.