In 2015, a Yale study using satellite imagery and forest inventories found that Earth has about 3.04 trillion trees. In contrast, the Milky Way has between 100 and 400 billion stars, meaning there are over seven trees for every star. These forests produce oxygen, absorb carbon dioxide, and provide essential wildlife habitats. However, about 15 billion trees are lost each year and overall numbers have dropped by nearly half since the start of human civilization. | The History Page