Deforestation is the complete removal of native vegetation existing in a given area.

The removal or cutting of isolated trees or a few trees within an area of native vegetation, where the remaining vegetation remains standing, does not constitute deforestation. Therefore, selective logging, forest management, and understory burning that may result in vegetation thinning or other processes of native vegetation degradation are not considered deforestation alerts. 

The definition of deforestation encompasses a number of specific aspects, which are clarified below in order to accurately characterize the data.

• Deforestation or Native Vegetation Suppression – Deforestation is commonly associated with the complete removal of forest vegetation. In this report, the term deforestation is used in a broader sense and includes any and all removal of native vegetation, whether primary or secondary vegetation, as well as the removal of non-forest vegetation, such as grasslands and savannas. Therefore, in this report, we use the term native vegetation suppression.

• Deforestation Alert - A deforestation alert refers to an event or indication of deforestation at a specific location. 

• Deforested Area - The area effectively affected by the removal of native vegetation. 

• Deforestation Detection Date – The date on which deforestation was detected and/or identified by the original detection systems. 

• Deforestation Occurrence Date – Refers to the period during which the deforestation occurred. This information is determined based on the available satellite imagery used by MapBiomas Alerta and reflects the most likely timing of the event according to the observed records.

• Observed Deforested Area  – The spatial extent directly quantified by comparing satellite images from different dates (before and after the deforestation). MapBiomas Alerta works exclusively with the concept of observed area.

• Deforestation Rate – The official deforestation rate reported by PRODES, which uses observed area information to estimate deforestation that occurred throughout the territory, including areas that could not be directly observed.

• Deforestation Rate of Change - refers to the ratio between the total deforested area and the number of days elapsed between the beginning and end of deforestation, usually expressed in hectares or km2 per day. In MapBiomas Alerta, the speed is underestimated because the calculation is approximate, based on the dates of the satellite images selected and available to best document the moment before and after the deforestation episode.

• Degradation – Degradation involves the partial removal of areas of native vegetation. The MapBiomas Alerta initiative deals only with cases of deforestation.