1 23 Spatial Information Research ISSN 2366-3286 Volume 25 Number 3 Spat. Inf. Res. (2017) 25:501-512 DOI 10.1007/s41324-017-0117-3 Assessing anthropogenic disturbance on forest health based on fragment grading in Durgapur Forest Range, West Bengal, India Shyamal Dutta, Mehebub Sahana & Sanat Kumar Guchhait