Acta Forestalia Fennica vol. 32 | 1927

Discs were collected from sample trees of Scots pine (Pinus sylvestris L.) in different types of peatlands and mineral soil sites in Kajaani, Rovaniemi, Kuusamo; Suojärvi, Pielisjärvi, Evo and Lokalahti in Finland. The growth ring series of the different areas reach as far as in the 1600th century in some sample plots. The diameter growth shows patterns that repeat in cycles of 7, 11, 21, 35 and 70 years. However, the cycles are not exactly equally long. The average lengths of the cycles are relatively similar both in peatlands and in mineral soil sites.

The PDF includes a summary in German.

• Boman, E-mail: ab@mm.unknown

Because the cross-sectional area of a tree stem is ellipsis, it cannot be determined exactly with only the diameter measurement.  The article presents a formula and the calculation of the exact cross-sectional area. If the cross-sectional area is calculated as arithmetic mean of two diameter measurement, varies the error between two limit values. The error becomes smallest by calculating the area based on the biggest and the smallest diameter measurements. 

• Heikkilä, E-mail: th@mm.unknown

Sample trees of Betula sp. were felled in North Karelia in different forest site types. The stands, both mixed and pure stands, had been regenerated in areas where shifting cultivation had been practiced. Sample trees represented breast height diameters up to 43 cm. Diameter was measured in distances of 1/10 of the height of the tree to calculate the stem form. The form factor was higher for the good forest site types than the poor sites. The volume tables were calculated based on the assumption that diameter does not affect the form factor. Comparing the volume table to the original data, it was found that the table seems to form a successful fitting of the data. Control data proved that the method seems to give a good fitting to the used data. Thus, the volume table can be used to measure volume of birch stands in North Karelia.

The PDF includes a summary in German.

• Hildén, E-mail: nh@mm.unknown

To achieve a continuous and constant timber flow over a longer time period, the forest holding structure should be close to normal forest or regulated forest. Concept of normal forest is presented as the model of achieving the highest possible sustainable yield and hence also the best economic return. The article discusses the regulations on the management of a forest holding with the view on regulating the forest yield.   

Felling need to be planned according to the forest site and tree species. The main tree species for silvicultural purposes are pine, spruce and birch. After the widely used controlled burning of forests the state of Finnish forests is mostly weak and far from the “normal forest”. Majority of forests are of young and there are lots of broadleaved forests.  Because of the great variation of the forest sites and their productivity as well as the small size of holdings in Finland, the selection of forest management regime, mainly the felling style (clear cut or light selection) is also important. The idea of management plans is represented.  

• Lönnroth, E-mail: el@mm.unknown