Nature's Beckon, an environmental activist group in the North-east has expressed serious concern over the massive illegal felling of trees inside Chakrashila wildlife sanctuary, a Nature's Beckon press release said. "A team of Nature's Beckon visited the area and found large-scale felling of trees has taken place and there were evidences of hand-sawing operations in 13-number of saw-piets", the release added. Meanwhile, Nature's Beckon has reported about the incident to Mr S Doley, Principal Chief Conservator of Forest, Assam and urged him to take necessary action soon.