The Ministry of Agriculture and Forestry has carried out forest inventories and drawn up silvicultural plans. According to surveys, between 1945 and the late 1970s foresters had cut trees faster than the forests could regenerate them. Nevertheless, between the early 1950s and 1981, Finland was able to boost the total area of its forests by some 2.7 million hectares and to increase forest stands under 40 years of age by some 3.2 million hectares. Beginning in 1965, the country instituted plans that called for expanding forest cultivation, draining peatland and waterlogged areas, and replacing slow-growing trees with faster-growing varieties. By the mid-1980s, the Finns had drained 5.5 million hectares, fertilized 2.8 million hectares, and cultivated 3.6 million hectares. Thinning increased the share of trees that would produce suitable lumber, while improved tree varieties increased productivity by as much as 30 percent.