Recent news has highlighted the fragility and importance of tropical rainforests to our ecosystem, including in helping to mitigate climate change and enhance biodiversity. While negative headlines have dominated recently, particularly about the destruction of rainforests in Brazil, there is potential hope through targeted restoration programs that are driven by informed decision-making based on the use of spatial data and remote sensing.
In recent research, countries committed to the Bonn Challenge which aims to restore more than 350 million hectares of destroyed tropical rainforests by 2030, have been identified as some of the most likely countries where restoration of tropical rainforest areas should concentrate. Using peer-reviewed GIS datasets and remote sensing data, 88% of the needed restoration effort could focus on just six countries that are likely to help restore tropical rainforest growth. These countries are Rwanda, Uganda, Burundi, Togo, South Sudan, and Madagascar. While they only represent less than 10% of tropical rainforested areas, they represent countries that can most likely provide the right type of rainforest cover to help preserve not only biodiversity and help fight climate change, but these restoration efforts could assist with local economic development and opportunities.
Assessing Restoration Benefits
In the recent work, conservation hotspots are identified based on high rates of forest loss and having high concentration of endemic species. Four key restoration benefits are identified that can be derived from spatial landscape data using a combination of multiple satellite datasets at 1-km2 resolution and land-based data collected through ground-truthed work, with biodiversity conservation, climate change mitigation, climate change adaptation, and human water security being the variables identified in finding relevant landscapes. Physical data are derived from such datasets as carbon sequester maps that have been published as well as rainfall potential in different regions.
Mapping Restoration Feasibility
While benefits are one factor, the other major assessment requirement is feasibility of given landscapes to be restored to tropical rainforests. In this case, three variables are identified using land opportunity costs, landscape variation in forest restoration success, and restoration persistence chance. These variables intersect policy and local potential for action to restore given areas. Countries also had to show potential in bringing relevant stakeholders, such as farmer, developers as well as ecologists, together in mitigating impact. The combined data created what is called a restoration opportunity score, with the top 10% areas identified (in 1-km2 intervals) resulting in the countries identified as the six relevant countries for major restoration investment. The results provide a literal map for policy makers to enable them to focus their efforts into specific regions, helping to conserve the remaining tropical rainforests, restoring damaged/destroyed areas in a way that balances stakeholder interests, and enable the planet to benefit through keeping biodiversity and mitigating carbon loss. (The geospatial data for “Global restoration opportunities in tropical rainforest landscapes” can be downloaded from the paper’s Supplementary Materials page)
The Need for Smaller-Scale Analysis
Although the new research highlights the benefits of integrating various remote sensing datasets and GIS data, even smaller-scale analyzes may need to be brought into the full implementation of tropic rainforest restoration schemes. It is evident, for instance, at the microbial scale that soil quality and composition changes as rainforests are destroyed. Old growth rainforests provide benefits that are not easily replaced, thus the quality of forest will not be the same as before and may take decades or even never fully replicate the carbon capture some patches of rainforest provide prior to their destruction. Efforts to restore may need to look at local factors such as these in choosing given areas to restore and assessing their potential.
While the current news cycle makes the destruction of the Amazon a clear threat in exacerbating climate change and the destruction of biodiversity, recent work is also highlighting there might be some hope in restoring the health of tropical rainforests in places that can balance the needs of the planet and local stakeholders. Restoration efforts can focus on specific countries, placing their investments in restoring tropical rainforests where they can maximize benefits. This is made possible through decades of satellite data collection and field observations that can now be utilized to inform future policy decisions. Increasingly scientists are beginning to see that their planning and research should focus on how to mitigate major global environmental threats, and being specific about where policy can best achieve results, using available resources and regions that may enable the most beneficial plans to be implemented.
 For an example dataset utilized to build the assessment, see: Poorter, Lourens, Frans Bongers, T. Mitchell Aide, Angélica M. Almeyda Zambrano, Patricia Balvanera, Justin M. Becknell, Vanessa Boukili, et al. 2016. “Biomass Resilience of Neotropical Secondary Forests.” Nature530 (7589): 211–14. https://doi.org/10.1038/nature16512.
 For more on this latest research on restoring tropical rainforests, see: Brancalion, Pedro H. S., Aidin Niamir, Eben Broadbent, Renato Crouzeilles, Felipe S. M. Barros, Angelica M. Almeyda Zambrano, Alessandro Baccini, et al. 2019. “Global Restoration Opportunities in Tropical Rainforest Landscapes.” Science Advances5 (7): eaav3223. https://doi.org/10.1126/sciadv.aav3223.
 For more on soil change and composition in tropical rainforests and restoration efforts, see: Bonner, Mark T. L., Diane E. Allen, Richard Brackin, Tim E. Smith, Tom Lewis, Luke P. Shoo, and Susanne Schmidt. 2019. “Tropical Rainforest Restoration Plantations Are Slow to Restore the Soil Biological and Organic Carbon Characteristics of Old Growth Rainforest.” Microbial Ecology, August. https://doi.org/10.1007/s00248-019-01414-7.