Accounting for albedo change to identify climate-positive tree cover restoration

Restoring tree cover changes albedo, which is the fraction of sunlight reflected from the Earth’s surface. In most locations, these changes in albedo offset or even negate the carbon removal benefits with the latter leading to global warming. Previous efforts to quantify the global climate mitigation benefit of restoring tree cover have not accounted robustly for albedo given a lack of spatially explicit data. Here we produce maps that show that carbon-only estimates may be up to 81% too high. While dryland and boreal settings have especially severe albedo offsets, it is possible to find places that provide net-positive climate mitigation benefits in all biomes. We further find that on-the-ground projects are concentrated in these more climate-positive locations, but that the majority still face at least a 20% albedo offset. Thus, strategically deploying restoration of tree cover for maximum climate benefit requires accounting for albedo change and we provide the tools to do so

Review and assessment of smartphone apps for forest restoration monitoring

With increased interest in forest restoration comes an urgent need to provide accurate, scalable, and cost‐effective monitoring tools. The ubiquity of smartphones has led to a surge in monitoring apps. We reviewed and assessed monitoring apps found through web searches and conversations with practitioners. We identified 42 apps that (1) automatically monitor indicators or (2) facilitate data entry. We selected the five most promising from the first category, based on their relevance, availability, stability, and user support. We compared them to traditional field techniques in a well‐studied restoration project in Costa Rica. We received further feedback from 15 collaborator organizations that evaluated these in their corresponding field restoration sites. Diameter measurements correlated well with traditional tape‐based measurements (R2 = 0.86–0.89). Canopy openness and ground cover showed weaker correlations to densiometer and quadrat cover measurements (R2 = 0.42–0.51). Apps did not improve labor efficiency but do preclude the purchase of specialized field equipment. The apps reviewed here need further development and validation to support monitoring adequately, especially in the tropics. Estimates of development and maintenance costs, as well as statistics on user uptake, are required for cost‐effective development. We recommend a coordinated effort to develop dedicated restoration monitoring apps that can speed up and standardize the collection of indicators and provide evidence on restoration outcomes alongside a centralized repository of this information

Data from: Edaphic factors, successional status, and functional traits drive habitat associations of trees in naturally regenerating tropical dry forests

1. Many studies have examined individual environmental drivers of tropical tree species distributions, but edaphic and successional gradients have not been considered simultaneously. Furthermore, determining how functional traits influence species distributions along these gradients may help to elucidate mechanisms behind community assembly. 2. To assess the influence of environmental filtering on tropical dry forest (TDF) tree species distributions we used forest inventory data from sites with large edaphic and successional gradients in NW Costa Rica. Our goals were to determine (1) whether edaphic or successional factors are more important determinants of the abundance of individual tree species in regenerating TDF, (2) how species-level functional traits are related to edaphic and/or successional niche associations of tree species, and (3) correlations between species-level edaphic and successional niche associations. 3. The distributions of 82 focal tree species were strongly driven by both edaphic and successional gradients. Overall, 94% of species responded to soil chemistry, 89% to soil texture, and 94% to stand age gradients. Some functional traits were correlated with the edaphic and successional niche associations of TDF tree species. Species that specialized on soils with high total nutrient concentrations had higher foliar nutrient concentrations (nitrogen and phosphorus) and lower leaf dry matter content (LDMC). Species with wider stand age niches had lower LDMC and wood density. There were no correlations between edaphic and successional niche optima of TDF tree species. 4. Our results indicate that successional and edaphic gradients concurrently drive community assembly in regenerating TDF. Moreover, our work underscores the importance of considering how the functional characteristics of TDF trees dictates species distributions across environmental gradients

Organic Wastes and Tropical Forest Restoration

In a recent publication, we documented the benefits of using agricultural waste (specifically, leftover orange peels from a commercial orange juice factory) to promote forest recovery at a site in Costa Rica. While we showed unambiguously positive impacts on soil conditions, forest biomass, and tree diversity, our ability to infer mechanisms behind this recovery was limited because the project was never replicated. It appears our work is one of only a handful of peer-reviewed studies testing the use of unprocessed agricultural waste as part of a tropical forest restoration initiative. We argue that regardless of the mechanism, there are first-principle reasons to expect that minimally processed (and thus low-cost) agricultural wastes could be utilized to accelerate tropical forest restoration in a variety of contexts, potentially creating a new class of biodiversity-friendly carbon offsets that may address previous concerns about linking tropical forestry to global carbon markets. We outline research initiatives that could lead to a richer understanding of when and where it is safe and effective to utilize agricultural and other wastes in tropical forest restoration endeavors