Quantify the value of planting and maintaining trees.
A single mature tree absorbs 22 kg of CO2 per year and produces enough oxygen for 2 people. Over its lifetime, one tree can absorb over 1 tonne of CO2. But carbon storage is just the beginning. The USDA Forest Service estimates a single urban tree provides $16 in air quality improvement, $13 in stormwater management, $36 in energy savings (shade cooling), and $13 in CO2 reduction annually — roughly $78/year in total benefits. Large deciduous trees planted on the south and west sides of buildings reduce air conditioning costs by 20-30%. A mature tree canopy intercepts 15,000-20,000 liters of rainfall per year, reducing stormwater runoff and flood risk. Trees increase property values by 7-15% ($10,000-$15,000 for a typical home). Urban trees also reduce ambient temperature by 2-8°C through evapotranspiration, combating the urban heat island effect. Neighborhoods with more tree cover have lower crime rates, better mental health outcomes, and higher social cohesion.