Restoring oak forests on bare ground using topsoil translocation Article uri icon

abstract

  • Seedling establishment in degraded Oak forests is often hampered by harsh soil conditions, which may take decades to recover. Translocating the top soil from old-growth healthy forests to severely impaired sites can improve environmental conditions and eventually trigger self-repairing forest succession. We tested the potential of this strategy to enhance the seedling establishment of three oak species (Quercus eduardii Trel., Quercus viminea Trel. and Quercus resinosa Liebm.) in a fragmented seasonally dry oak forest with severely weathered soils in Mexico. We transferred old-growth forest topsoil with and without leaf litter to a degraded clearing. To separate habitat from soil effects, we also moved topsoil from the clearing into the old-growth forest. The effects of soil translocation on seedling establishment varied according to life-stage (acorn, seedling, and young sapling), season (rainy vs dry) and site (clearing vs forest). In the clearing, transferred forest topsoil covered with leaf litter yielded the maximum germination probability rates, which were 7 ± 1%25 higher than in native weathered soil. Once seedlings emerged, survival probability decreased in the transferred soil in both sites, i.e. the weathered clearing soil in the forest habitat, as well as the forest soil in the clearing. Furthermore, transferring forest soil and leaf litter enhanced initial seedling growth in the clearing, increasing growth rates by 60 ± 5%25 compared to native weathered soil. Increased soil moisture due to soil translocation enhanced seedling establishment in the clearing, but decreased germination and survival rates in the forest. Our results suggest a dynamic water stress mechanism: (1) lack of moisture in soils with poor water retention capacity during the dry season; and (2) water excess during the rainy season in more mesic soil habitats. Given the elevated cost of translocating topsoil and the damage this causes at donor-sites, we recommend considering this intervention only for sites with reduced water retention capacity, prolonged dry seasons and slow soil formation. © 2018 Elsevier B.V.

publication date

  • 2018-01-01