This manual describes the step-by-step procedures by which ImpactMatters analyzes tree planting nonprofits. We recommend reading the program analysis methodology first.
For nonprofits that operate both urban forestry and reforestation programs, we analyze each program independently using the respective calculation methods for each subtype. Following that, we sum up the total impact and costs for each component program to get a total figure for the nonprofit.
We note the country in which the tree planting program(s) operates. This information is usually found in:
Form 990, part I, 1
990, part III, 1
990, part III, 4a
Financial disclosure forms
Note: From here on this list of sources will simply be referred to as the “common areas” where information is found.
Dates of impact¶
To fully capture the impact of tree planting nonprofits, we estimate the effect of trees planted across the average lifespan of a tree. Based on the research literature, we set the average lifespan of an urban tree to 10 years, and for forest trees, 30 years. As a result, when recording the dates of final impact, we set the end date to 10 years after the start date for urban forestry programs, and 30 years after for reforestation programs. For nonprofits featuring both urban forestry and reforestation programs, we take the average of the two and set the end date 20 years after the start date.
Number of trees planted¶
We report the number of trees planted by looking at the common areas described above. The location where nonprofits report the number of trees planted is varied and inconsistent across organizations. We use the number of trees planted in the year for which we have financial information for the nonprofit.
If no data is available on the number of trees planted, we do not evaluate the nonprofit.
Carbon sequestered per tree¶
To calculate the carbon sequestered per tree for a given nonprofit, we must first determine the biome of the location where the nonprofit plants trees. Nonprofits with U.S. urban forestry programs are given a catch-all “urban” biome designation. Reforestation programs are given a biome designation based on the list of 14 biomes established by the World Wildlife Fund (W.W.F.).1
To give a planting location a biome designation, we first see whether the nonprofit reports the habitat types where it works. If this information is not reported, we then search the W.W.F. website to find which biome or biome(s) apply to the nonprofit’s planting locations. If a nonprofit does not report a specific location and only lists a country or broader region where it works, we search the W.W.F. website for that country as a whole and list all the biomes that apply to that country. An example: A nonprofit works in Nepal, but does not specify where it plants trees within the country. But we know that six biomes could apply to Nepal: Tropical moist broadleaf forests; Tropical coniferous forests; Temperate broadleaf forests; Temperate coniferous forests; Tropical grasslands; Montane grasslands and shrublands. We select all six biomes for that nonprofit.
Some nonprofits may plant across a wide swath of countries without describing more specific planting locations. In cases like this where it may be difficult to designate biomes, we take a global average of the carbon sequestration rate for every biome.
Once all the biomes have been determined, we then input the data for carbon sequestered per tree. Each biome has a separate rate of carbon sequestration taken from the research literature. For organizations that plant across multiple biomes, we take the average of all the sequestration rates for each biome to use in calculations.
Probability of displacement¶
To estimate the impact of a nonprofit, we estimate the extent to which its tree planting might displace that of others (e.g., city government, other nonprofits). We calculate the likelihood of displacement by assuming that a nonprofit becomes more likely to displace other tree-planting organizations as the availability of plantable land decreases.
For reforestation programs, we calculate available land based on the biomes the nonprofit works in. The figure we use for each biome is taken from the research literature. For nonprofits that plant in multiple biomes, we take the average across biomes. Again, for nonprofits where we are not able to narrow down possible biomes, we take a global average of all biomes.
For urban forestry programs, we use data from the i-Trees analysis tool. Based on locations provided by the nonprofit, we search for the location within i-Trees and record both the percentage of plantable space and the canopy percentage for a given location. While some nonprofits list the cities where they work, others may refer to a broader area where they work (e.g., the Twin Cities metropolitan area). In cases like this, we will record the county in addition to the city and possibly surrounding counties depending on the information the nonprofit provides.
i-Trees has two possible data sources, high resolution data (HiRes) and the 2011 National Land Cover Database (N.L.C.D.). HiRes data is only available for locations where Urban Tree Canopy assessments have been submitted. HiRes layer is usually updated twice per year, often May and December. We use 2011 N.L.C.D. data for areas that lack HiRes data.
When isolated costs of the tree planting program are reported in the common areas (usually form 990 section III, line 4a, or section IX line 24a), we use those costs directly. This includes all costs directly related to tree planting, such as procuring seeds or seedlings, maintaining tree nurseries or tree farms, transporting and planting trees, and pruning and watering.
We include tree maintenance expenses in our calculations. We make the simplifying assumption that, on average, all tree planting programs are operating at a steady state. For example, a nonprofit incurs costs in 2018 to plant new trees, but it also incurs costs to maintain trees planted in 2017. Assuming there is no significant change in the scale of its operations from one year to the next, we expect that the cost to maintain the 2017 trees is an appropriate substitute in our calculation for the future cost of maintaining the 2018 trees.
In other cases, nonprofits may lump together the cost of planting trees with other programs and activities not directly tied to planting trees. For example, a community beautification program may include litter collection and cleanup alongside tree planting expenses. In these situations, we net out a fixed 5 percent of program cost for each activity that was initially lumped in.
We assume beneficiary costs are $0 unless they are reported. Some nonprofits charge beneficiaries a nominal fee for tree planting services, mostly in residential planting contexts. We deduct this revenue from the nonprofit’s program cost, then add this revenue amount to beneficiary costs.
Nonprofits tend to charge heavily subsidized fees for tree planting, so we assume that people who pay nonprofits to help them plant trees would not otherwise pay market rates for trees. Said differently, these are costs incurred as a result of the nonprofit’s intervention and therefore should be included in our calculation.