Pine Stand Density Influences the Regeneration of Acacia saligna Labill. H.L.Wendl. and Native Woody Species in a Mediterranean Coastal Pine Plantation

Abstract

Mediterranean plantations are the most suitable areas to assess vegetation dynamics and competitive interactions between native and exotic woody species. Our research was carried out in a coastal pine plantation (Sicily) where renaturalization by native species (Pistacia lentiscus L. and Olea europaea var. sylvestris) and invasion by Acacia saligna (Labill.) H.L.Wendl. simultaneously occur. The regeneration pattern of woody species in the pine understory was evaluated in six experimental plots along a stand density gradient, from 200 to approximately 700 pines per hectare. Both pine stand density and regeneration by native species had a significant negative relationship with Acacia natural regeneration. Olea regeneration was positively correlated with stand density, while Pistacia showed a non-significant relationship. Saplings of both native species were mostly less than 1 m high, whereas approximately 70% of Acacia individuals were higher than 1 m. We found that 400 pines per hectare should be considered a minimum stand density to keep Acacia under control, while favouring the establishment of native species in the understory. The successful control of Acacia requires an integrated management strategy, including different forest interventions according to stand density: thinning, control measures against Acacia, and renaturalization actions.

Native Plant Diversity and Composition Across a Pinus radiata D.Don Plantation Landscape in South-Central Chile—The Impact of Plantation Age, Logging Roads and Alien Species

“…This would increase connectivity of native patches, stand structure as well as stand heteroneneity with potential positive effects for native biodiversity [36,65]. In clearcuts and young plantations, residual native tree species from previous mature stages should not be actively removed; (2) Alternative forest management options for alien species reduction in the vicinity of natural forests: As alien species decreased with plantation age, a continuous cover of pines in densities of around 400 trees/ha [78] as a buffer zone around natural forests might reduce the propagule pressure of alien species. This, however, would require management options that allow for a continuous cover [79].…”

“…This, however, would require management options that allow for a continuous cover [79]. Such alternative management options can further facilitate a regeneration of natural forest understories [78]. In Mediterranean Europe Pinus radiata plantations have a rotation period of approximately 40 years and were found to converge in understory community composition with time when compared to natural forest understories [35].…”

Carbon stock increases up to old growth forest along a secondary succession in Mediterranean island ecosystems

“…Forests in the Mediterranean basin have been subject to millennial human exploitation, which deeply modified and simplified their composition, structure, functioning and the ability to provide ecosystem services [1–2]. However, in the last decades, the reduction in the intensity of forest management, and the increase in the protection regime of European forests have allowed the progressive development of structural and biological traits typical of old growth forests (OGFs) [3].…”

Effects of Seed Size and Sand Burial on Germination and Early Growth of Seedlings for Coastal Pinus thunbergii Parl. in the Northern Shandong Peninsula, China

“…Although the quality of planted forests in China in general is perceived low, planted forests in the coastal area play a significant role in reducing natural disasters, stabilizing shore lines, and sustaining biodiversity [3][4][5]. How to renew coastal protection forests without destroying their ecological functions is an important research topic [5,6].…”