Each mature tree captures about 20KG of carbon a year. When millions, billions, trillions of trees grow that is serious carbon impact with real economic power behind it. Trees do this while growing, and their leaves fill our atmosphere with oxygen. Dirty polluted air is purified by those same leaves. Captured carbon only makes a difference when it is stored for the long haul. Planted forests must be left standing for many generations to make a impact on climate change.

Most of the carbon a forest pulls from the air during photosynthesis isn’t built into the tree trunks. Instead, it is pushed out the tree roots into the soil under the forest. There microorganisms in the soil food web exchange water and minerals for the sugars the trees made with carbon during photosynthesis. Forests grown of a wide mixture of native trees create diverse and healthy below ground environments which hold much more carbon below the surface than above. The implications are clear; we mustn’t just grow forests; we must grow healthy diverse forests of native trees to capture the most carbon.

Forests of native trees create valuable habitat for wildlife. From the unseeable soil dwelling microorganism living in symbiosis with tree roots to the massive elephants of Xishuangbanna, creatures are dependent on environments such as healthy forests of native trees. Insects and birds, we need to control pests in our crops, are fortified by their forest homes and their populations suffer as forest health decreases.

About 88% of flowering plants rely on animals for pollination. Forests provide essential habitat for pollinators. These insects and birds are critical workers in our planet’s functioning. Each flower they visit becomes a fruit and seeds keeping us and our forests alive. World-wide pollinator populations are dropping, imperiling natural systems and agriculture alike. It is critical to keep forests healthy, so pollinator populations stabilize and improve in health.

Forests control and minimize surface water runoff keeping rivers and oceans cleaner. And the branches, and roots of the forest slow rainfall allowing it to enter the soil and become clean groundwater. The global water cycle is driven by forests, each tree releasing vast quantity of moisture into the air where it forms clouds and rain.

Everyone is drawn to a forest. We are relaxed and refreshed. A picnic, a hike, or forest bathing provides people the world over power and mental recharge to solve humanity’s problems.

Trees improve air quality by trapping particulates, absorbing gaseous pollutants such as O3, SO2, NO2, PM10 and releasing oxygen. By cooling urban heat islands and shading parked cars, trees indirectly reduce ozone levels.

Large amounts of CO2 are sequestered by urban forests in the process of photosynthesis where carbon is used to build wood and feed soil dwelling microorganisms. Of the carbon held within the tree, 50% is kept in its trunk, 30% in its branches, and 3% in its leaves. The urban forest filling and shading a city plays a real role in reducing CO2 levels.

A healthy and leafy urban canopy is a strong distraction from the normal noise of the city. The rustling of leaves and tweeting of birds add interest and build natural sounds back into the city’s structure.

People are healthier when they have regular contact with nature. Physical and mental health improve when the urban forest provides a place of escape, entertainment, and an area to exercise. A city is better to live and work in when its forest is full. People’s responsibility and attitude towards the environment will improve, and it builds a sense of belonging and self-awareness among citizens.

Street trees reduce stormwater runoff by slowing water getting to the ground and slowing its movement on the ground. This allows more to enter the soil. It relieves pressure on urban sewage systems and decreases the expenses of urban facility maintenance. Trees filter out the pollutants in runoff and purify the storm water, mitigating the effects of water pollution on groundwater, rivers, lakes and even oceans.

Trees near buildings help decrease the temperature in summer by shading and evaporation. This reduces the energy required to cool the air inside the buildings. Shaded sidewalks and cars are cooler and fewer people die from heat exhaustion. And in winter, evergreen trees limit the velocity of winds and help retain heat inside the buildings.

The urban forest contributes vast intangible benefits and urban beauty. Because of our innate desire for a connection to nature we find streets and cityscapes with many urban trees more appealing, and those locations have greater property valuation.