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ORIGINAL RESEARCH article

Front. Ecol. Evol.
Sec. Conservation and Restoration Ecology
Volume 12 - 2024 | doi: 10.3389/fevo.2024.1461573

How much to cut? Finding an optimal thinning intensity of encroaching woody species for the herbaceous community in an East African savannah

Provisionally accepted
Teshome Abate Teshome Abate 1,2*Tesfaye Abebe Tesfaye Abebe 2Anna Treydte Anna Treydte 3,4,5
  • 1 Wondo Genet College of Forestry and Natural Resources, Hawassa University, Hawassa, Ethiopia
  • 2 College of Agriculture, Hawassa University, Hawassa, Ethiopia
  • 3 Ecology of Tropical Agricultural Systems, Hans Ruthenberg Institute, University of Hohenheim, Stuttgart, Germany
  • 4 School of Life Sciences and Bioengineering, Nelson Mandela African Institution of Science and Technology, Arusha, Tanzania
  • 5 Department of Physical Geography, Faculty of Science, Stockholm University, Stockholm, Stockholm, Sweden

The final, formatted version of the article will be published soon.

    Globally, bush encroachment poses a great threat to the conservation of biodiversity and range-land productivity. However, control methods of encroaching woody species have rarely been ex-perimentally quantified. We assessed the impact of tree thinning intensities on tree mortality, and the herbaceous community in Borana rangelands , an Ethiopian savannah ecosystem. At two 1.4 ha areas of mono-specific Vachellia drepanolobium stands, we set up 20 m x 10 m experimental plots with four tree-thinning treatments (0%, 33%, 67%, and 100% tree removal), with three rep-lications in a randomized complete block design (RCBD) across two sites . The 0% plot was left uncleared and used as control. Over two growing periods, we monitored resulting tree mortality, coppicing, seedling mortality, and recruitment as well as herbaceous layer attributes (diversity, biomass) and the rangeland conditions. Tree thinning intensity significantly increased abundance of the dominant desirable grass species. Total herbaceous and grass species richness, diversity and biomass were significantly improved under high (100%) and moderate (67%) tree removal intensity. We conclude that tree thinning at moderate intensity (67%) was most effective in en-hancing mortality of encroached trees, and improving grass diversity, and herbaceous biomass. We stress that effective tree thinning requires post-thinning management and repeated bush con-trol measures. Our findings contribute to development of recommendations on controlling bush encroachment, species restoration, and rangeland productivity in Ethiopian rangelands.

    Keywords: Bush encroachment, restoration, Tree removal, Vachellia drepanolobium, Ethopia

    Received: 08 Jul 2024; Accepted: 26 Nov 2024.

    Copyright: © 2024 Abate, Abebe and Treydte. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

    * Correspondence: Teshome Abate, Wondo Genet College of Forestry and Natural Resources, Hawassa University, Hawassa, Ethiopia

    Disclaimer: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.