Forestle saves 0.1 square meters (about 0.1 square yards) of rain forest per search event. It guarantees to donate 90% of its advertisement revenue to the Adopt an Acre program of is partner organization The Nature Conservancy. The Nature Conservancy uses these donations by Forestle to sustain rain forest. As of February 7, 2009, about 100000 square meters of rain forest have been saved [1].

A Forestle search is also essentially CO2-neutral, as Forestle.org offsets the carbon-dioxide emissions caused by electricity consumed by all Forestle servers, the network infrastructure as well as the computers of each user by purchasing an equivalent amount of renewable energy certificates [2]. The certificates are purchased from a part of the 10% of revenue left after conserving rain forest. This makes Forestle one of the few web search sites that are green certified.

Over the years, The Nature Conservancy has faced a number of criticisms. They fall into the following main categories:

    * Too close to business. Some environmentalists consider big business to be antagonistic to environmentalism, and disapprove of The Nature Conservancy's corporate collaborations[17]. The Conservancy argues that since corporations have such a significant impact on the environment, they must be engaged in finding ways to do business that do not harm the environment. Moreover, they provide significant resources. In the most egregious incident, Nature Conservancy protected-land became the site of a severe oil spill caused by an on-site drilling company. The Conservancy, however, apologized for the incident and instituted a broad policy review in the wake of the incident
    * Questionable resale. There have been allegations of The Nature Conservancy obtaining land and reselling it at a profit, sometimes to supporters,[18] who have then made use of it in ways not perceived by all as being sufficiently environmentally-friendly. The rationale for the resale has been that the profit allows The Nature Conservancy to increase its preservation of more important locations.[19] However, the Conservancy does have a no-net-profit policy that has been in effect for years for all transactions of this type.