Forest boundary delineation is one of the key issues of forest management for Swiss National Forest Inventory (NFI). The proposed approach in this paper focuses on the delineation of forest boundaries with special emphasis on spatially contiguous and reproducible results by using both aerial images and LIDAR data. The used Green Vegetation Index (GVI) is helpful to find green vegetation areas. With the information provided by canopy height model (CHM) obtained from LIDAR data, the forest area where CHM has a regular density can be detected successfully. The selected JSEG segmentation method has been found to produce useful homogenous sub-areas. The combination of JSeg segmentation result and the texture features extracted by Gabor wavelet leads to the whole forest area detection and obtain proper forest boundaries. Preliminary results are encouraging, regarding an automatic process and delivers robust delineation of forest boundaries. Future research is focused on appropriate Gabor filter selection to reduce computation burden and other better data fusion methods to obtain more accurate forest boundary delineation.