Advances and shortfalls in applying best practices to global tree-growing efforts

As global tree-growing efforts have escalated in the past decade, copious failures and unintended consequences have prompted many reforestation best practices guidelines. The extent to which organizations have integrated these ecological and socioeconomic recommendations, however, remains uncertain. We reviewed websites of 99 intermediary organizations that promote and fund tree-growing projects to determine how well they report following best practices. Nearly half the organizations stated tree or area planting targets, but only 25% had measurable, time-bound objectives. Most organizations discussed the benefits local communities would receive from trees, but only 38% reported measures of these outcomes. Non-profit organizations with greater prior experience converged more closely on best practices, and their level of scientific expertise was positively associated with clearer project selection standards. Although many tree-growing organizations acknowledge the importance of clear goals, local community involvement, and monitoring, our results raise questions regarding whether long-term benefits are being achieved and emphasize the need for stronger public accountability standards.

Methods
1. Description of methods used for collection/generation of data (see Schubert et al. 2024 and Supporting Information: Extended Methods for more details): Data collection occured Jan-Mar 2023. We identified 99 tree-growing intermediary organizations from recently published studies -- Bosshard et al. (2021) and Martin et al. (2021) -- and by searching Google and online charity platforms. These constituted private sector organizations that: (1) fund tree-growing or forest landscape restoration projects that are implemented by local organizations and landholders in multiple regions (i.e., at least multiple states/provinces within a country) (2) have a web presence with information communicating the organization’s restoration activities to potential funders. We excluded organizations that are primarily funded by government sources that are less dependent on web pages to share information with potential donors, fundraise for other intermediary organizations, or are exclusively service providers for hire (e.g., planted trees as a business). Each organization was assessed for data collection by at least two authors, who followed a protocol with survey prompts designed to collect information pertaining to the ten questions funders should ask about reforestation (Holl and Brancalion 2022). Data collection consisted of recording information to address a combination of categorical and open-ended questions that describe the organizations and their tree-growing practices. All web pages of the organizations primary website, in addition to all publicly-available annual and financial reports corresponding to tree-growing standards were subject to review. These prompt questions are detailed in the Extended Methods section of Schubert et al. 2024 Supporting Information. Cumulative review times ranged 50–170 min per organization, depending on the extent of information available. We conducted a final search 21–25 March 2023 for new annual reports to ensure we used the most updated information.

2. Persons responsible for data entry and proofing: K. E. Battaglia, C. N. Blebea, C. J. P. Seither, H. L. Wehr, Y. Sheikhvand, and S. C. Schubert

3. Methods for processing the data: The data presented here have been redacted slightly from the original survey spreadsheets for multiple reasons. First, we provide a numeric code 1-99 to identify each organization rather than actual organization names since the goal of the study was to characterize trends rather than evaluate individual organizations. Similarly, some descriptive open-ended columns include lengthy responses, quoted text, and project names/locations which we hold confidential. We have included the data necessary to repeat the quantitative analyses in the study. From the data initially collected from our online surveys, we calculated an index to evaluate the extent of organizations’ adherence and transparency to best practices based on our expanded questions, hereafter ‘best practices index’. The index was based on a sum of 21 responses with a total possible value of 22 points derived from presence and extent of information provided by organizations (e.g., no information = 0, vague response = 0.5, information provided = 1). We used multiple regression to test whether certain organizational characteristics including organization type (non-profit or for-profit), past experience (prior number of trees or area planted/conserved), and staff scientific expertise predicted the best practices index. To examine relationships between specific ordinal variables, we used Kendall rank correlation. Data processing, operations, analysis, and figure rendering were performed in R 4.3.0 (R Core Development Team 2023). For further information concerning code and additional data collected, send inquiries to Spencer Schubert ([e-mail]).