TREE FACTS

• Trees replenish our oxygen, filter out air pollution, contribute to better mental health and wellbeing, they are vital for the water we drink,  help cool our cities and towns, and are home to many species of plant, birds and wildlife.
• Air pollution, including carbon monoxide, lead, nitrogen dioxide, ozone, particulate matter – PM10 and PM2.5 – and sulfur dioxide, is are known to cause health concerns in humans, including headaches, lung, throat and eye irritation, respiratory and heart disease, and cancer. There is an urgent need for more trees and forests in Ontario, and in Southern Ontario in particular. If this comes as a surprise to you, think of the urban sprawl where forests are in serious jeopardy, and remember older neighbourhoods where trees that were planted decades ago will die soon, leaving a void in the urban forest. 
• Tree planting in rural areas of southern Ontario declined significantly in the early 1990’s. Until that time, 20 to 30 million trees were planted per year in the region, however in 1998, that number fell to less than 2 million trees planted annually. Now, Trees Ontario, working with its partners, is rebuilding the infrastructure to increase forest cover to the required levels.
• Heat from the earth is trapped in the atmosphere due to high levels of carbon dioxide (CO2) and other heat-trapping gases that prevent heat from being released into space – creating a phenomenon known as the "greenhouse effect." 
• Increasingly, carbon dioxide is being recognized as a "greenhouse gas" pollutant with potentially devastating consequences, which include global warming, dramatic changes in rainfall patterns, and rising sea levels that threaten flooding in coastal cities. Trees and forests are playing a vital role in helping to counteract the increase of this gas in the atmosphere.
• Trees sequester (trap) carbon dioxide (CO2) from the atmosphere. They do this during photosynthesis to form carbohydrates that are used in plant structure/function and return oxygen back to the atmosphere as a byproduct.
• About half of the greenhouse effect is caused by CO2. Trees therefore act as a “carbon sink” by removing the carbon and storing it as cellulose in their trunk, branches, leaves and roots, while releasing oxygen back into the air.
• Trees also reduce the greenhouse effect by shading our homes and office buildings. This reduces air conditioning needs up to 30 per cent, thereby reducing the amount of fossil fuels burned to produce electricity.
• This combination of CO2 removal from the atmosphere, carbon storage in wood, and the cooling effect makes trees a very efficient tool in fighting the greenhouse effect.
• A healthy tree stores about 13 pounds of carbon annually – or 2.6 tons per acre each year. An acre of trees absorbs enough CO2 over one year to equal the amount produced by driving a car 26,000 miles.
• The size of trees is important when it comes to carbon sequestration and speaks to the need for sustained growth. Carbon sequestration rates can be up to 90 times greater for healthy large trees than healthy small trees. For these reasons, good management of the urban forest is critical to achieve maximum benefits.
• During growth, the carbon captured by trees is locked away for significant periods – often hundreds of years. Carbon is stored very quickly with fast-growing tree species, and they store it much longer than crops or tropical trees. And if we restore and re-forest promptly, the growing forest provides a positive balance as a sink. Young thriving trees and forests are the key. Most mature forests are in a state of balance (i.e. they store as much CO2 as they emit).
• Climate change is already having a negative effect on existing trees. More trees must be planted to offset the ongoing destruction of Ontario’s forests which is a direct result of global warming. There is growing evidence that environmental changes caused by elevated atmospheric carbon dioxide (CO2) and its potential effects on global climate will alter forest ecosystems in Ontario.