Reforestation is defined as:

Reforestation is accurately defined as the process of planting trees to restore a forested area that has been depleted or damaged. This practice aims to re-establish a healthy forest ecosystem, which can provide numerous environmental benefits, such as enhancing biodiversity, improving air and soil quality, and sequestering carbon dioxide, thereby mitigating climate change.

The importance of reforestation lies in its ability to restore not only the physical presence of trees but also the complex interactions these trees have within their ecosystems. This includes supporting wildlife habitats and promoting ecological balance. In contrast, the options related to land removal or ecosystem protection do not capture the essence of reforestation, which is specifically focused on the act of planting trees to re-establish forested areas. Similarly, monitoring invasive species, while an important aspect of conservation, does not align with the core concept of reforestation.