Assaying techniques to improve dry season plantings in eastern Madagascar. Issue 8 (13th June 2022) - Logan, Chris M.
Abstract : Rampant deforestation in eastern Madagascar highlights the urgency of protecting and restoring its unique rainforests. This experiment addresses a restoration bottleneck: the precipitous drop in seedling survival during dry season plantings. We assayed nine soil, water, and shade treatments that were codeveloped with local farmers to improve survival and growth of 17 native tree species planted on a denuded hillside during one dry season. Most treatments had no effect; however, rustic shade structures decreased transplant shock mortality (i.e. mortality within the first 2 months after planting) by 75%. This improvement is broadly accessible; it can be accomplished with materials freely and easily accessed in most farmlands in eastern Madagascar. Also, survival varied among species and seedling size, suggesting that carefully selecting species that are resistant to the harsh dry periods, improving shade availability, and planting larger seedlings of each species could lead to further gains in native tree performance in dry season plantings. Short‐lived dry season resistant species (e.g. Uapaca sp., Trema orientalis, Psiadia sp., Macaranga sp., and Pittosporum ochrosiifolium ) could also provide shade as nurse trees for less resistant canopy trees, which have the potential to be established through enrichment plantings in years following the initial planting.