Forest Ecosystems (Jan 2024)
Effect of the rotation frequency in the eucalypt plantations
Abstract
In the last century, eucalypt plantations are increasing all over the world. Concretely, in the Basque Country (northern Iberian Peninsula), 7% of pine plantations have been recently substituted by eucalypt plantations, where little is known about their ecological impact on soil and plant diversity. However, the most relevant impact is due to forest management, as Eucalyptus globulus Labill. plantations have a short harvesting cycle, 12–15 years rotations. In fact, the species is able to regenerate from stumps; therefore, those plantations are replanted after 3–4 rotations. This type of invasive and frequent management could lead to further adverse effects on the ecosystem. The aim of this study was to characterise and compare the eucalypt plantations newly established (New: never been harvested) with older ones (Old: several times harvested and grown from stumps), having been established for at least 35 years, and to identify the primary factors that could influence the richness and diversity of vascular plant species in those plantations. The results indicated that both plantations exhibited comparable characteristics with respect to deadwood (volume and decay stage) and tree size and density. However, the Old plantations exhibited higher forest heterogeneity, pH, and higher shrub and herb richness and diversity. Overall, generalist and invasive species were found in the New plantations, while in the Old plantations, typical species of the native forests were also observed. The factor that influenced plant diversity was the volume of deadwood. Regarding life forms, higher altitude and proximity to watercourses favoured tree diversity; and lower canopy cover, shrub diversity. In conclusion, the longer the plantation has been established, the greater the number of species that are able to survive and adapt. This is probably due to the fact that management disturbance is specific and not sufficient to remove the already established plants and the soil seed bank.
