Browsing by Subject "uneven-aged Scots pine"

The purpose of this study was to define economically optimal stand structures and harvesting cycles for uneven-aged Scots pine (Pinus sylvestris L.) in Finland. According to a recent proposal by Ministry of Agriculture and Forestry, uneven-aged management will be included in the new Forest Act as an alternative for future forest management in Finland. Uneven-aged management is also planned to be included in the Forest management practice recommendations by the year 2014. However, only little knowledge exists on optimal uneven-aged management in Finland, particularly on uneven-aged Scots pine. This thesis aimed at filling the gap in knowledge regarding economically optimal management of uneven-aged Scots pine. So far, economic studies on uneven-aged Scots pine have been conducted only in a static optimization framework, where optimal stand structure is constrained with a classic “reversed-J” diameter distribution, and transition cuttings are limited to one single harvest. In this work, stand structures and harvesting cycles were optimized for maximum volume yield and maximum stumpage revenues by applying both static and dynamic optimization. Until now, no dynamic optimization has been conducted on uneven-aged Scots pine. Static optimization was applied for different growth sites from mesic sites in Southern Finland (MT1300) to sub-xeric sites in Central Finland (VT1100). Mesic sites in Southern Finland were also optimized in a dynamic framework. A density-dependent individual tree model with latest ecological growth models was applied in optimization. The large-scale nonlinear problems were solved by means of numerical computing with discrete-time formulations. Present value of stumpage revenues was maximized applying 1% and 3% discount rates. Economically optimal harvesting cycle became 40 years in Southern Finland (site MT1300), and even longer at more northern and less fertile site types. Results imply that it is not economically optimal to manage Scots pine with a traditional selection method with short harvesting cycles, but rather with a heavy harvesting regime including low after cut basal areas. When maximizing present value of stumpage revenues, optimal after cut basal areas in Southern Finland were as low as 5 m2 (1% discount rate) and 3.2 m2 (3% discount rate) per hectare. A proposal of Ministry of Agriculture and Forestry suggests minimum after cut basal areas of 10–11 m2 per hectare for Southern Finland, which clearly exceed the optima of this study. Contrary to the existing results for uneven-aged Scots pine, economically optimal stand structure did not follow the classic reversed-J diameter distribution.