Many global environmental agendas, including halting biodiversity loss, reversing land 45 degradation, and limiting climate change, depend upon retaining forests with high ecological 46 integrity, yet the scale and degree of forest modification remains poorly quantified and mapped. 47 Page 3 of 54By integrating data on direct and indirect forest pressures and lost forest connectivity, we generate 48 the first globally-consistent, continuous index of forest condition as determined by degree of 49 anthropogenic modification, which we term 'forest health'. Globally, only 17.4 million km 2 of 50 forest (40.5%) can be considered in high health (mostly found in Canada, Russia, the Amazon,
51Central Africa and New Guinea) and only 27% of this area is found in nationally-designated 52 protected areas. Of all the world's forests found within protected areas, only 56% can be 53 considered in high health. Ambitious policies that prioritize the retention of forest health are now 54 urgently needed alongside current efforts aimed at restoring the health of forests globally. 55 56 MAIN TEXT 57 58 65bodies (e.g. 5), and it is now essential that the scientific community develop improved tools and 66 data to facilitate the consideration of the degree of forest modification in decision-making.
67Mapping and monitoring this globally will provide essential information for coordinated global, 68 national and local policy-making, planning and action, to help nations and other stakeholders 69 achieve the Sustainable Development Goals (SDGs) and implement other shared commitments 70 such as the United Nations Convention on Biological Diversity (CBD), Convention to Combat Ecosystem integrity is foundational to all three of the Rio Conventions (UNFCCC, UNCCD, 74 CBD ). As defined by Parrish et al. ( 6), it is essentially the degree to which a system is free from 75 anthropogenic modification of its structure, composition and function. Such modification causes 76 the degradation of many ecosystem benefits, and is often also a precursor to outright deforestation 77 (7, 8). Forests largely free of significant forest modification (i.e. forests having high ecosystem 78 integrity), typically provide higher levels of many forest benefits than modified forests of the 79 same type (9), including; carbon sequestration and storage (10), healthy watersheds (11), 80 traditional homelands for imperiled cultures (12), contribution to local and regional climate 81 processes (13), and forest-dependent biodiversity (14-17). Industrial-scale logging, fragmentation 82 by infrastructure, farming (including cropping and ranching) and urbanization, as well as less 83 visible forms of modification such as over-hunting, wood fuel extraction and changed fire or 84 hydrological regimes (18, 19), all degrade the degree to which forests still support these benefits, 85 as well as their long-term resilience to climate change (9). There can be trade-offs however, 86 between the benefits provided by less-modified forests (e.g., carbon sequestration) and those 8...