This document describes the use of aerial photography and airborne LiDAR to estimate individual tree heights in forest stands. The advantages and disadvantages in the use of LiDAR systems are revised and a data fusion analysis with digital aerial photography is proposed. The work shows an example of these techniques in a forested area in Scotland. An algorithm has been devised to extract a high resolution digital terrain model of the bare ground. This information was used to obtain a tree canopy model as a difference between the laser first pulse and the model of the underlying terrain. The information at a tree level was obtained by image segmentation and classification. The analysis showed a good estimation of individual tree canopies and heights