by which time 1,540 km of inland forests were included within Forest Reserves. this area had increased to 2,430 km by 1954, but forest destruction by shifting cultivation in up-river interior regions was by then regarded by the state as a problem. the export of timber from Brunei was banned in 1957 because the domestic demand for timber had until then continued to exceed the available domestic supply, requiring imports from Sarawak. This ban was relaxed in response to the surplus of timber which had accumulated by the late 1960 s, but was reinstated in 1970. further development of the timber industry saw some, strictly restricted, exports of sawn timber resume by the early 1980 s.