Diagnosing Causes of Pine Forest Decline: The Cases of a Production Forest and a Protected Area

The pine wood nematode (PWN) Bursaphelenchus xylophilus is maybe the most consequential invasive pine pathogen in Eurasia, causing the pine wilt disease (PWD). It was introduced in Portugal (and in Europe) in 1999, leading to the enforcement of strict regulations attempting to control its dispersion. However, the system put in place to deal with this epidemic does not account with other factors affecting pine forest health and decline and gets easily overwhelmed by natural disturbances in ecosystem dynamics, such as severe drought and forest megafires. It also fails to consider diverse local contexts, such as nature preserves, ownership and liability. Presented here are the cases of a protected and a production forest, discussing the different causes of forest decline and their different management strategies according to the objectives of the stakeholders, in a region under quarantine since the introduction of the PWN in the country. © The Authors 2023