The biodiversity-productivity relationship (BPR) is foundational to our understanding of the global extinction crisis and its impacts on ecosystem functioning. Understanding BPR is critical for the accurate valuation and effective conservation of biodiversity. Using ground-sourced data from 777,126 permanent plots, spanning 44 countries and most terrestrial biomes, we reveal a globally consistent positive concave-down BPR, showing that continued biodiversity loss would result in an accelerating decline in forest productivity worldwide. The value of biodiversity in maintaining commercial forest productivity alone—US$166 billion to 490 billion per year according to our estimation—is more than twice what it would cost to implement effective global conservation. This highlights the need for a worldwide reassessment of biodiversity values, forest management strategies, and conservation priorities. (Résumé d'auteur

The identity of the dominant microbial symbionts in a forest determines the ability 70 of trees to access limiting nutrients from atmospheric or soil pools 1,2 , sequester 71 carbon 3,4 and withstand the impacts of climate change 1-7 . Characterizing the global 72 distribution of symbioses, and identifying the factors that control it, are thus integral to 73 understanding present and future forest ecosystem functioning. Here we generate the first 74 spatially explicit map of forest symbiotic status using a global database of 1.2 million forest 75 inventory plots with over 28,000 tree species. Our analyses indicate that climatic variables, 76 and in particular climatically-controlled variation in decomposition rate, are the primary 77 drivers of the global distribution of major symbioses. We estimate that ectomycorrhizal 78 (EM) trees, which represent only 2% of all plant species 8 , constitute approximately 60% of 79 tree stems on Earth. EM symbiosis dominates forests where seasonally cold and dry 80

Live woody vegetation is the largest reservoir of biomass carbon, with its restoration considered one of the most effective natural climate solutions. However, terrestrial carbon fluxes remain the largest uncertainty in the global carbon cycle. Here, we develop spatially explicit estimates of carbon stock changes of live woody biomass from 2000 to 2019 using measurements from ground, air, and space. We show that live biomass has removed 4.9 to 5.5 PgC year−1 from the atmosphere, offsetting 4.6 ± 0.1 PgC year−1 of gross emissions from disturbances and adding substantially (0.23 to 0.88 PgC year−1) to the global carbon stocks. Gross emissions and removals in the tropics were four times larger than temperate and boreal ecosystems combined. Although live biomass is responsible for more than 80% of gross terrestrial fluxes, soil, dead organic matter, and lateral transport may play important roles in terrestrial carbon sink.