Dear all, The International Tree Mortality Network, an initiative of the IUFRO task force on monitoring trends and patterns in global tree mortality, continues the online seminar series on *March 15, 4 pm CET*, with: *Bonaventure Ntirugulirwa* *Title: **Mortality of Afrotropical trees in a temperature manipulation experiment: Result from the Rwanda TREE project* _Abstract:_ Knowledge on mortality responses of tropical trees and communities under projected warmer climate is limited. Trees in tropical montane forests (TMFs) are considered particularly vulnerable to climate change, but this hypothesis remains poorly evaluated due to data scarcity. To reduce the knowledge gap on the warming response of TMFs, we have established a field experiment along an elevation gradient ranging from 2400 m a.s.l. (15.2 °C mean temperature) to 1300 m a.s.l. (20.6 °C mean temperature) in Rwanda. Twenty tree species, native to East and Central Africa, from two forest types of origin (transitional rainforest at 1600 – 2000 m a.s.l, and TMF at 2000 – 3000 m a.s.l.) and two successional groups, early (ES) and late succession (LS), were planted in multispecies plots at three sites along the gradient. Tree growth and survival of 5400 trees was monitored regularly over two years. The results showed that ES trees from lower elevations grew faster at warmer sites while several of the LS species, especially from higher elevations, did not respond or grew slower. Moreover, tree mortality increased in a warmer climate and this was more pronounced in high-elevation and LS species compared to lower-elevation and ES tree species. ES species with transitional rainforest origin strongly increased in proportion of stand basal area at warmer sites, while tropical montane forest species declined, suggesting that higher-elevation and LS species are at risk to be outcompeted by lower-elevation and ES species in a warmer climate. We conclude that tree mortality and growth responses combined may lead to modified tree community composition in a warmer climate, favouring lower-elevation and ES tree species. This has important implications for biodiversity and carbon storage of Afromontane forests. _Bio:_ Bonaventure Ntirugulirwa is a research fellow in the Forest Productivity and Improvement Program at the Rwanda Forestry Authority of the Ministry of Environment in Rwanda. He is a PhD candidate at the University of Rwanda and at the University of Gothenburg in Sweden. His research focus are native tree species, their relation to ecological regions, and the influence of climate change on growth and mortality. *Please register for the Zoom Webinar: * https://zoom.us/webinar/register/2716463846296/WN_KN6QanBkTQye_cLZyvFWKg Note that the talks might be recorded. * * *Previous seminars:* Seminar # 1: Matt Hansen - Global forest monitoring using satellite data https://youtu.be/snUSGNb9bAQ Seminar # 2: Flavia Costa - Tree mortality in the Amazon across local hydrological gradients: how water table depth may save or condemn trees as climate changes https://youtu.be/5wmzX9ldn4Q Seminar #3: Belinda Medlyn - Tree mortality in Australian ecosystems: past, present and future https://youtu.be/T6S9VKklbyc Seminar #4: Nate McDowell - Rising tree mortality in the Anthropocene https://youtu.be/vdAXQ8CibKA Seminar #5: Lisa Hülsmann - Tree mortality modeling – a tool for ecological inference and a challenge for projecting forest dynamics https://youtu.be/Yzsa0p7lq7c Seminar #6: Craig D Allen - The global emergence of hotter-drought drivers of forest disturbance tipping points https://youtu.be/5NlkIQOzl2Y <https://www.youtube.com/watch?v=5NlkIQOzl2Y> Seminar #7: Yude Pan - Impacts of disturbances on leaf area index and productivity of terrestrial ecosystems https://youtu.be/mhHxGPVZXXE <https://youtu.be/mhHxGPVZXXE> Seminar #8: Viacheslav Kharuk - Conifer decline and mortality in Siberia https://youtu.be/2X4ZoUQa8jA <https://youtu.be/2X4ZoUQa8jA> Seminar #9: Barbara Bentz - Recipes for Climate-Induced Bark Beetle-Caused Tree Mortality https://youtu.be/ddjMbYvuX6I <https://youtu.be/ddjMbYvuX6I> Seminar #10: Ana Bastos - Climate variability, extremes, and attribution of high-impact ecological events: challenges and ways forward https://youtu.be/jhTwbQ6cffA <https://www.youtube.com/watch?v=jhTwbQ6cffA> * * *Visit us at:* https://www.tree-mortality.net/ https://www.iufro.org/science/task-forces/tree-mortality-patterns/ -- --- Dr. (habil.) Henrik Hartmann Group leader Plant Allocation MPI for Biogeochemistry Hans Knöll Str. 10 07745 Jena, Germany Contact:hhart@bgc-jena.mpg.de <mailto:hhart@bgc-jena.mpg.de> Phone:+49.3641.576294 Mobile:+49.171.8188273 Website: https://www.bgc-jena.mpg.de/bgp/index.php/HenrikHartmann/HenrikHartmann *Initiatives*: International Tree Mortality Network https://www.tree-mortality.net/ IUFRO Task Force on monitoring of global tree mortality patterns and trends https://www.iufro.org/science/task-forces/tree-mortality-patterns/ <https://www.tree-mortality.net/>https://www.tree-mortality.net/