Terra preta soil, made by humans 1-2000 years ago, contains charcoal - known as "biochar" - that helps retain soil nutrients. Little is known about biochar effects in the tropics, particularly to aid forest restoration. We propose to apply biochar to native tree plantations, and to assess soil properties, soil organisms, and tree growth in experiments and in forests with terra preta soil in Ecuador. Biochar has potential to directly aid forest restoration and take pressure off natural forests.