Historical Development of the Portuguese Forest: The Introduction of Invasive Species

Abstract

Portugal is a country with a territorial dimension of approximately 90,000 km2. However, the forest occupies a prominent position, since it represents about 35% of the total area of the country. Portuguese people always had a very close connection with the forest, which has provided the necessary resources for the development of its communities. The geological substratum of continental Portugal is very old and may therefore have witnessed the evolution of its plants, from the early beginning to the present time, as well as all sort of historical and environmental landmarks such as glacial periods or mass extinctions. Also, from the perspective of human occupation, Portuguese territory was crossed by hunter-gatherer populations who, initially, were constantly moving and looking for sustenance, but at a later stage, chose to settle. This relationship between human populations and the forest is, thus, very old and demonstrates the interdependence between the subsistence of the populations and the resources exploitation. Currently, the main national economic groups are based on forest industries, which depend directly on the exploitation of the three dominant species, Eucalyptus globulus Labill., Pinus pinaster Aiton and Quercus suber L., demonstrating the human role in the development of the forest, motivated by the satisfaction of its needs. This work reviews the historical development of the forest in mainland Portugal, from geological times to the present, including the arrival of exotic species that later acquired invasive behaviors and now occupy significant areas of the national territory.

Carbon Sequestration Potential of Forest Invasive Species: A Case Study with Acacia dealbata Link

“…With Acacia dealbata being the species with the greatest dissemination in Portugal, Martins et al (2016) presented forms of invasive alien mapping of Acacia dealbata Link using ASTER multispectral imagery to quickly identify the areas seriously affected by this species [54]. This species has attracted the most attention mainly due to its high rate of [55], but also because of the difficulty that often exists in identifying the problem and in making decisions about the measures to be taken to control and combat it. A recent study by Vaz et al (2020) assessed stakeholders' perceptions in Northern Portugal about these non-native acacias and their invasion processes, social-ecological impacts, and management, and verified the existence of a great lack of knowledge (and experience) regarding the recognition and identification of non-native trees, as well as that on their introduction and invasion history, drivers of dispersion, costs and benefits, and effective management [56].…”

Comment on nhess-2021-38

“…CC BY 4.0 License. Portugal is where the most extensive forests in the country (Nunes et al, 2019), particularly abundant in pine and eucalyptus trees, two species that have been associated with extreme wildfire events (Maia et al, 2014). Additionally, dense Mediterranean forests over hard-to-reach mountains can also be found in these areas, which combined enhance the difficulty of the firefighting efforts.…”

Comment on nhess-2021-38

“…Additionally, dense Mediterranean forests over hard-to-reach mountains can also be found in these areas, which combined enhance the difficulty of the firefighting efforts. The Algarve, which despite being located in the south coast, also has some mountains with forests, surrounded by a considerably dry and arid terrain, especially in the summer (Nunes et al, 2019). Beira Baixa is the region which presented the most burned area during the period 2001-2016, with almost 124,000 ha in total.…”