Abstract

Oak trees are biodiversity hotspots in many landscapes and provide habitats for several organism groups, including species that are rare or threatened by extinction. Oak regeneration in the northern hemisphere is often poor, which is a serious problem in many oak-rich conservation forests. Competition from other vegetation and browsing by ungulates are two factors that limit oak regeneration. In 13 mixed oak-rich forests with high values for biodiversity we tested conservation-oriented thinning. Trees and shrubs were harvested for biofuel, but the main aim was to favour oak regeneration and biodiversity. On average, 23% of the initial basal area was removed during the winter 2002/2003. After thinning, we set up exclosures to protect oak seedlings from browsing. In 2012, after ten growing seasons, the exclosures had favoured regeneration of oak by reducing ungulate browsing, though the effect was weak. Tall oak saplings (>130 cm) were present in exclosures at five sites, and no such new stems were recorded in control plots with browsing. These five sites were characterized by higher canopy openness, and probably higher light availability, compared to the other sites. Other broadleaves, and especially shrubs, increased much more in density and height than oaks, in both exclosures and control plots. Thus, conservation-oriented thinning in combination with fences to protect oak seedlings from browsing ungulates, increased oak regeneration in the mixed conservation forests, but control of competing understory vegetation in exclosures is probably also needed. (C) 2015 Published by Elsevier B.V.

Keywords

Canopy disturbance; Forest restoration; Succession; Ungulates; Browsing; Quercus spp.

Published in

Forest Ecology and Management
2015, Volume: 354, pages: 1-9
Publisher: ELSEVIER SCIENCE BV

SLU Authors

• Löf, Magnus

  • Southern Swedish Forest Research Centre, Swedish University of Agricultural Sciences
    

Associated SLU-program

SLU Plant Protection Network


Sustainable Development Goals

SDG15 Protect, restore and promote sustainable use of terrestrial ecosystems, sustainably manage forests, combat desertification, and halt and reverse land degradation and halt biodiversity loss


UKÄ Subject classification

Forest Science
Ecology


Publication identifier

DOI: https://doi.org/10.1016/j.foreco.2015.07.004

Permanent link to this page (URI)

https://res.slu.se/id/publ/69725