Seed Origin and Protection Are Important Factors Affecting Post-Fire Initial Recruitment in Pine Forest Areas

Manuel Lucas-Borja,Daniel Moya,Jorge De Las Heras,Pedro Tíscar,Peter Fule,Thierry Onkelinx,David Candel-Pérez

doi:10.3390/f8060185

Abstract

Initial seedling recruitment is one of the most critical stages for plants in the Mediterranean basin. Moreover, wildfires and post-fire environmental conditions might deteriorate regeneration success, which can lead to problems for sustainable forest restoration and forest persistence. On this context, different seed origins and pine species may be better adapted to new environmental conditions remaining after forest fires and seed protection might modulate seedling initial recruitment. This study evaluates the effects of seed origin (Pinus nigra Arn. subsp. salzmannii Dunal (Franco) from lowland, midland and upland distribution areas), pine species (Pinus pinaster Aiton, Pinus sylvestris L. and Pinus nigra Arn. subsp. salzmannii Dunal (Franco)) and seed protection on seed emergence and early seedling survival after forest fires in the Cuenca Mountains. In addition, a greenhouse experiment was set up under controlled conditions to test seedling performance and to compare initial seedling growth of different P. nigra seed origins growing in field and greenhouse conditions. Results showed that wetter spring seasons and P. nigra seed origins from midland and upland distribution growing in their natural habitat distribution perform better that P. sylvestris and P. pinaster. Seed protection is an important factor modulating the above-mentioned trend. P. nigra seeds growing at the greenhouse experiment showed differences in growth for extreme (upland or lowland) P. nigra distribution.

Highlights

Current decreasing precipitation and increasing temperatures, together with the growing likelihood of extreme drought events, may heighten the vulnerability of forest ecosystems in the Mediterranean Basin [1]
The study findings showed that P. nigra and P. sylvestris emergence rates were higher than P. pinaster and that seedling survival rates were higher for MA and HA P. nigra seed origins for this experiment and for protected seedlings
The necessary conditions for a successful seed emergence may depend on specific environmental factors, while suitability for seedling survival can be related to different conditions

Summary

Introduction

Current decreasing precipitation and increasing temperatures, together with the growing likelihood of extreme drought events, may heighten the vulnerability of forest ecosystems in the Mediterranean Basin [1]. Increasing forest fire severity is expected, affecting forest soils and forest composition, persistence and stability over the Mediterranean region [2]. In this context, knowledge about potential post-fire regeneration of Forests 2017, 8, 185; doi:10.3390/f8060185 www.mdpi.com/journal/forests. Recent and predicted fire regimes in the Mediterranean area may restrict the establishment of some species or may result in a change in the species composition [5,6]. These changes have important consequences on plant biodiversity

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