What technology best assists in assessing changes in forest cover over time?

The use of polar-orbiting satellites is particularly effective for assessing changes in forest cover over time because they can provide comprehensive, consistent, and high-resolution imagery across vast areas. These satellites orbit the Earth at a relatively low altitude and can capture images of the same locations periodically, allowing for the monitoring of temporal changes in vegetation, such as deforestation, reforestation, and changes in forest density.

The capability of polar-orbiting satellites to cover large geographical areas, combined with their ability to collect data in various spectral bands (including visible, infrared, and microwave), enables detailed analysis of forest health and cover. They can also transmit real-time data which helps in tracking short-term changes, making them a robust tool for researchers and environmentalists studying forests.

Aerial photography, while useful, is limited in coverage compared to satellite data and typically requires aircraft, which can be cost-prohibitive for extensive areas. Ground-based surveys provide valuable on-the-ground detail but lack the scalability of satellite data, making them less effective for wide area assessments. Weather balloons primarily collect atmospheric data rather than ground-level cover, thus are not applicable for forest cover assessments.