Forests provide many ecological services, including protecting surface waters from runoff pollution. A study conducted in the Hubbard Brook Experimental Forest showed that streams in deforested areas had much higher stream flows than nearby forested areas due to higher levels of runoff reaching the streams after a rainfall.

The terrestrial biomes of the world store almost three times as much carbon in above-ground biomass and soil as is found in the atmosphere, making them vital carbon sinks. Forests hold the most by far. Most of the carbon in tropical forests is in above-ground biomass, whereas in boreal forests, the majority is in the soil and leaf litter, where cold year-round temperatures retard decomposition. Maintaining forest integrity is crucial to retain this carbon-storage ecosystem service.