Health effects of trees, biodiversity and global climate benefits. Trees are important – some people are oblivious to that. Trees give us oxygen – oxygen makes us feel better, makes us healthier, it makes Earth habitable for people and animals. They mitigate climate change. Trees clean the air. They clean the water. Trees are the center of ecosystems -- everything from other plants to wildlife to microbes to people depends on trees! They are resting and feeding points for migrating birds. Trees act as barriers to hurricanes. They provide shade, which adds to our comfort. Trees have economic benefits – increase worker and student productivity, reduce air conditioning costs, and increase property values. Neighborhoods seem safer with more trees.