Current issue: 55(2)
An occurrence of Cronartium Peridermium Strobi Kleb has been found in a privately owned garden in Tampere. They are found in several types of currant that the fungus uses as alternate host. The fungi have earlier been found on eastern white pine and now seemingly for the first time on stone pine.
The moisture content of the wood has negative impact on transport, storage and use of wood, particularly this can be noticed on firewood. The moister the wood the harder is the transportation and storing. The high percentage of moisture also reduces the heating power of fire wood.
Drying of the wood of different tree species was studied at the forestry institute Tuomarniemi with following experiment setup: pines, spruces, birches, aspens and alders were logged and cut into one-meter split billets. Then they were dices according Huber’s formula. The wood was stacked in three similar ricks (stacks), varying the direction of the cut surface. The various tree species were distributed evenly to every rick. The split billets were weighted straight after manufacturing and after every month.The wood dries fastest during spring and summer months. The direction of the cut surface of split billets in the rick makes no big differences in drying. The coniferous wood dries up to lower moisture content than broadleaved woods.
The article is a review on shifting cultivation, its methods and use in Finland, and its effect on the condition of forests. Shifting cultivation decreases forest reserves not only by burning large amounts of wood. Of the area used for shifting cultivation, 10-50% can be open land. The older age classes of forests are often missing, and range of tree species shift towards deciduous trees. This causes lack of large timber. The shorter the rotation, the less well the most valuable trees survive on the area. One reason is lack of seed trees. Of the coniferous trees, Scots pine (Pinus sylvestris L.) is able to survive in the burnt-over lands better than Norway spruce (Picea abies (L.) H. Karst.), because it can produce seeds at a relatively young age. Betula sp. and especially grey alder (Alnus incana (L.) Moench) regenerate well on burnt-over lands. Also the frequency of good seed years determine which tree species become the dominant species on a burnt-over site.
When shifting cultivation is abandoned, deciduous trees keep their advantage over coniferous trees, because the wood of coniferous trees is used more in the surrounding villages. Pine and spruce spread to the burnt-over areas from the poorer sites that often had remained unburned. In densely populated areas in some counties in Savo in eastern Finland, where shifting cultivation was practiced intensively, Norway spruce became rare. Dominant tree species in the burnt-over areas became birch and pine.The article is divided in two parts. A German summary is included in a separate PDF
The hummocky peatlands are fairly common in Finland. Peatlands with hummock ridges are rare in southern Finland but become more common in northern parts of the country.
In the incompletely drained flark fens the development of the hummocks can be studied particularly well because they can be found in different development phases there. The phenomenon is more common in drained peatlands than in the peatland on their natural state.
The development of the hummock ridges is close related to development of the hummocks. The hummock ridges are formed only under certain circumstances.
Height increment of the hummock ridges is restricted by the same factors that prevent the unrestricted height increment of the hummocks. The hummock ridge may sink due to its own weight in unfrozen swamp, it may be eroded by frost, wind, flowing water or ice. Dead trees, shading or other detriments may prevent the growth of secondary peat.