Carl Salk

In Brazil, large‐scale restoration of native forest vegetation will only be achieved by fostering the effective participation of rural landowners. Understanding the social‐ecological factors (e.g. farmer and farm characteristics and government management) influencing farmers' decisions is a prerequisite. To effectively inform policymakers, researchers and farmers must evaluate forest restoration of these agricultural lands and the ecosystem services the forest provides. We determined the underlying reasons for decreasing, maintaining, or increasing native forest cover in farms of different sizes over the past 35 years and the perceived ecosystem services or disservices of forest. We conducted structured interviews with 90 farmers across 13 municipalities with high forest cover turnover between 1985 and 2015 in São Paulo state. The interviews addressed socio‐economic and environmental factors. The main reasons for farmers to decrease forest cover were government incentives and to increase agricultural area. In contrast, water conservation and legislation compliance were the main reasons for conserving and restoring forest cover. Large farmers reported more reasons to decrease native forest than small and medium farmers. The benefits most perceived by farmers are related to water resources, while food production and carbon sequestration were the least‐perceived benefits, indicating that there is a scale gap in these benefits between farmers, government, and organizations. Large farmers' positive engagement in restoring forests is related to their interest in carbon credit markets. These farm‐level results provide necessary input for developing goal‐oriented and targeted forest landscape restoration policies that aim to regain ecological functionality and enhance human wellbeing.

Aims: Overgrazing by excessive deer populations harms native plant communities across most north temperate and boreal regions. In regions where deer impact is particularly severe, fencing is sometimes employed as a conservation measure to safeguard rare and threatened species and ecosystems. Here we examine how forest vascular plant communities have been affected by 21 years of sika deer exclusion by fencing of a 900 ha area.Location: Nikko National Park, Tochigi prefecture, Japan.Methods: We surveyed vascular plant cover in 240 plots and measured forest density on both sides of the fence in stands dominated by larch (Larix kaempferi) and oak (Quercus crispula).Results: Vascular plant species richness was found to be lower in forest areas protected by the fence. At the same time, dwarf bamboo, often the most abundant understory component in Japanese open forests, was taller and denser inside the fence where deer had been excluded. In addition, the lack of natural tree regeneration inside the fence, likely due to strong dwarf bamboo competition, was also notable. This suggests that deer exclusion has benefitted dwarf bamboo while inhibiting the competition of other species, thereby lowering vascular plant richness. Vascular plant communities outside the fence instead seem to be strongly shaped by abundant sika deer; several species found there are known to be unpalatable or grazing tolerant, and there were few tree seedlings.Conclusion: These results show that fencing to protect forest flora against overgrazing may have unintended consequences where there is a risk that competitive species can dominate understory plant communities. Instead of fencing, improved game management to maintain moderate deer populations may be a better strategy for large‐scale conservation of forest flora and for promoting natural tree regeneration.

Tropical forests are increasingly threatened by deforestation and degradation, impacting carbon storage, climate regulations and biodiversity. Restoring these ecosystems is crucial for environmental sustainability, yet monitoring these efforts poses significant challenges. Secondary forests are in a constant state of flux, with growth depending on multiple factors. Remote sensing technologies offer cost‐effective, scalable and transferable solutions, advancing forest restoration monitoring towards more accurate, efficient and real‐time data analysis and interpretation. This review provides a comprehensive evaluation of the current state and advancements in remote sensing technologies applied to monitoring tropical forest restoration. Synthesis and applications: This review brings together the state of the art of remote sensing technologies, such as very‐high‐resolution RGB imagery, multi‐ and hyperspectral imaging, lidar, radar and thermal‐infrared technologies and their applicability in monitoring forest restoration. In conclusion, this review emphasizes the potential of remote sensing technologies, coupled with advanced computational techniques, to enhance global efforts towards effective and sustainable forest restoration monitoring.

Global warming is leading understory and canopy plant communities of temperate deciduous forests to grow leaves earlier in spring and drop them later in autumn. If understory species extend their leafy seasons less than canopy trees, they will intercept less light. We look for mismatched phenological shifts between canopy and understory in 28 years (1995–2022) of weekly data from Trelease Woods, Urbana, IL, USA. The observations cover 31 herb species of contrasting seasonality (for 1995–2017), three sapling species, and the 15 most dominant canopy tree species for all years, combined with solar radiation, temperature and canopy light transmittance data. We estimate how understory phenology, cold temperatures, canopy phenology, and solar radiation have individually limited understory plants’ potential light interception over >2 decades. Understory and canopy phenology were the two factors most limiting to understory light availability, but which was more limiting varied greatly among species and among/within seasonality groups; solar radiation ranked third and cold fourth. Understory and canopy phenology shifts usually occurred in the same direction; either both strata were early or both were late, offsetting each other’s effects. The four light-limiting factors combined showed significant temporal trends for six understory species, five toward less light interception. Warmer springs were significantly associated with shifts toward more light interception in three sapling species and 19 herb species. Canopy phenology became more limiting in warmer years for all three saplings species and 31 herb species. However, in aggregate, these variables mostly offset one another; only one sapling and seven herb species showed overall significant (and negative) relationships between light interception and spring temperature. The few understory species mismatched with canopy phenology due to changing climate are likely to intercept less light in future warmer years. The few species with data for carbon assimilation show broadly similar patterns to light interception.

We present the results of a hybrid research design that borrows from both experimental techniques—experimental games—and observational techniques—surveys—to examine the relationships between basic human values and exposure to natural ecosystems, on the one hand, and collective action for resource governance, on the other. We initially hypothesize that more frequent exposure to forests, and more pro-environmental values will be associated with more conservation action. However, we find that other values—tradition and conformity—are more important than pro-environmental values or exposure to nature. Our results imply that resource governance is likely to be more successful where resource users hold values that facilitate cooperation, not necessarily strong pro-environmental values.

Involving members of the public in image classification tasks that can be tricky to automate is increasingly recognized as a way to complete large amounts of these tasks and promote citizen involvement in science. While this labor is usually provided for free, it is still limited, making it important for researchers to use volunteer contributions as efficiently as possible. Using volunteer labor efficiently becomes complicated when individual tasks are assigned to multiple volunteers to increase confidence that the correct classification has been reached. In this paper, we develop a system to decide when enough information has been accumulated to confidently declare an image to be classified and remove it from circulation. We use a Bayesian approach to estimate the posterior distribution of the mean rating in a binary image classification task. Tasks are removed from circulation when user-defined certainty thresholds are reached. We demonstrate this process using a set of over 4.5 million unique classifications by 2783 volunteers of over 190,000 images assessed for the presence/absence of cropland. If the system outlined here had been implemented in the original data collection campaign, it would have eliminated the need for 59.4% of volunteer ratings. Had this effort been applied to new tasks, it would have allowed an estimated 2.46 times as many images to have been classified with the same amount of labor, demonstrating the power of this method to make more efficient use of limited volunteer contributions. To simplify implementation of this method by other investigators, we provide cutoff value combinations for one set of confidence levels.

Drone‐based remote sensing is a promising new technology that combines the benefits of ground‐based and satellite‐derived forest monitoring by collecting fine‐scale data over relatively large areas in a cost‐effective manner. Here, we explore the potential of the GatorEye drone‐lidar system to monitor tropical forest succession by canopy structural attributes including canopy height, spatial heterogeneity, gap fraction, leaf area density (LAD) vertical distribution, canopy Shannon index (an index of LAD), leaf area index (LAI), and understory LAI. We focus on these variables’ relationship to aboveground biomass (AGB) stocks and species diversity. In the Caribbean lowlands of northeastern Costa Rica, we analyze nine tropical forests stands (seven second‐growth and two old‐growth). Stands were relatively homogenous in terms of canopy height and spatial heterogeneity, but not in their gap fraction. Neither species density nor tree community Shannon diversity index was significantly correlated with the canopy Shannon index. Canopy height, LAI, and AGB did not show a clear pattern as a function of forest age. However, gap fraction and spatial heterogeneity increased with forest age, whereas understory LAI decreased with forest age. Canopy height was strongly correlated with AGB. The heterogeneous mosaic created by successional forest patches across human‐managed tropical landscapes can now be better characterized. Drone‐lidar systems offer the opportunity to improve assessment of forest recovery and develop general mechanistic carbon sequestration models that can be rapidly deployed to specific sites, an essential step for monitoring progress within the UN Decade on Ecosystem Restoration.

Global efforts for biodiversity protection and land use-based greenhouse gas mitigation call for increases in the effectiveness and efficiency of environmental conservation. Incentive-based policy instruments are key tools for meeting these goals, yet their effectiveness might be undermined by such factors as social norms regarding whether payments are considered fair. We investigated the causal link between equity and conservation effort with a randomized real-effort experiment in forest conservation with 443 land users near a tropical forest national park in the Vietnamese Central Annamites, a global biodiversity hotspot. The experiment introduced unjustified payment inequality based on luck, in contradiction of local fairness norms that were measured through responses to vignettes. Payment inequality was perceived as less fair than payment equality. In agreement with our preregistered hypotheses, participants who were disadvantaged by unequal payments exerted significantly less conservation effort than other participants receiving the same payment under an equal distribution. No effect was observed for participants advantaged by inequality. Thus, equity effects on effort can have consequences for the effectiveness and efficiency of incentive-based conservation instruments. Furthermore, we show that women exerted substantially more conservation effort than men, and that increasing payment size unexpectedly reduced effort. This emphasizes the need to consider social comparisons, local equity norms, and gender in environmental policies using monetary incentives to motivate behavioral change.