As necessary data and information for forestry studies can be obtained directly from terrestrial measurements, it can be also collected by using remote sensing methods such as aerial photographs and satellite images. Although terrestrial measurements are much more accurate and precision compared to other techniques, however, working in large areas and using terrestrial method s are time consuming and not feasible in most cases. Therefore, in these types of studies, proportion of terrestrial measurements within entire study period should be minimized in order to save time and money. By using remote sensing method s, necessary updated data can be collected in large areas in a reliable manner within a short term. The main objective of this paper is to introduce important remote sensing data (aerial photographs and satellites data), explain their technical characteristics, and finally compare characteristics and evaluation of satellites data with those of aerial photographs.