1. (Forest) - The increase of the canopy cover or stocking within a forest. Explanatory note: For the purpose of having a harmonized set of forest and forest change definitions, that also is measurable with conventional techniques, forest improvement is assumed to be indicated by the increase of canopy cover and/or stocking of the forest through growth. In a more general sense forest improvement is the long-term increase of the overall potential supply of benefits from the forest, which includes wood, biodiversity and any other product or service. FRA 2000. FAO. 2002. Draft Analytical Framework on Forest-Related Definitions.
2. (Land) - Alteration in
the qualities of land that improves its potential for land use.
http://www.nscb.gov.ph/peenra/Publications/Compendium/glossary.PDF