Abstract

Aboveground competition is often argued to be the main process determining patterns of natural forest regeneration. However, the theory of multiple resource limitation suggests that seedling performance also depends on belowground competition and, thus, that their relative influence is of fundamental importance. Two approaches were used to address the relative importance of above-and below-ground competition on regeneration in a nutrient-poor pine (Pinus sylvestris) boreal forest. Firstly, seedling establishment beneath trees stem-girdled 12 years ago show that a substantial proportion of the seedlings were established within two years after girdling, which corresponds to a time when nutrient uptake by tree roots was severely reduced without disrupting water transport to the tree canopy, which consequently was maintained. The establishment during these two years also corresponds to abundances high enough for normal stand replacement. Secondly, surveys of regeneration within forest gaps showed that surrounding forests depressed seedlings, so that satisfactory growth occurred only more than 5 m from forest edges and that higher solar radiation in south facing edges was not enough to mediate these effects. We conclude that disruption of belowground competitive interactions mediates regeneration and, thus, that belowground competition has a strong limiting influence on seedling establishment in these forests.

Keywords

boreal forest; forest edge; pine regeneration; asymmetric competition; tree girdling

Published in

Forests
2014, Volume: 5, number: 9, pages: 2106-2121

SLU Authors

• Axelsson, Petter

  • Department of Forest Ecology and Management, Swedish University of Agricultural Sciences
    

• Lundmark, Tomas

  • Department of Forest Ecology and Management, Swedish University of Agricultural Sciences
    

• Högberg, Peter

  • Department of Forest Ecology and Management, Swedish University of Agricultural Sciences
    

• Nordin, Annika

  • Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences
    

Associated SLU-program

SLU Future Forests


Sustainable Development Goals

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


Publication identifier

DOI: https://doi.org/10.3390/f5092106

Permanent link to this page (URI)

https://res.slu.se/id/publ/60405