Maritime pine natural regeneration in Coastal Central Portugal: Effects of the understory composition

Abstract

Aim of study: To study the natural dynamics of Pinus pinaster natural regeneration in a post-fire scenario in three populations of Coastal Central Portugal, with severe ecological degradation due to plant invasions, and partially affected by the 2017 wildfires. Area of study: Three P. pinaster populations, located along a geographic gradient of about 140 km on Coastal Central Portugal: Mira, Tocha and Leira. Materials and methods: The density and establishment success of P. pinaster regeneration was studied in burnt and unburnt forest stands. Special focus was given to the effects of the cover by native and invasive species (mainly Acacia longifolia) on pine regeneration. Main results: Regeneration values considered sustainable (over 0.3 seedlings·m-2) were recorded in all three populations in burnt and unburnt plots, where only one of the three study sites showed signs of establishment difficulty. We recorded high levels of invasion which showed a negative relationship with regeneration density.. Research highlights: The cover of invasive flora was negatively correlated with pine regeneration, while the presence of native flora showed positive relations with density and height of pine natural regeneration.