Scattered unlawful patches in forest landscape not only cause adverse effects on soil and water conservation, but also deteriorate the integrity and functionality of the forest ecosystem. This study took a 548ha government-managed experimental forest as an example to investigate the effects of unlawful cultivation on the forest landscape. Based on land use maps of 1971 and 1998 produced by digital photogrammetry, a Markov model was constructed to project the extent of land cover changes in the future. A binary logit model was used to examine the possible factors contributing to the observed land cover changes, and to simulate the spatial patterns of cultivation in the future. Finally, 4 landscape indices were used to assess the effects of unlawful cultivation on the forest landscape. The results of this study showed that the occurrences of cultivation were related to elevation and proximity to private land. Cultivated areas have more-significant edge effects than shape effects on the landscape. Among the 4 indices examined, the total edge length was more sensitive to cultivation than were the others. On the other hand, cultivated areas appeared to have little effect on the fractal dimension of the dominant forest patch.