Articles containing the keyword 'luonnonnormaalit metsät'

Examination of stands developed under natural conditions can be used to provide basis for comparison for study of the development and yield of stands treated with intermediate fellings. In Finland, the first investigation and the yield and the structure of natural normal stands were published in 1920. This investigation on development and yield of the natural forests of Kainuu in southeastern Northern Finland is based on 92 sample plots on three forest types; Empetrum-Vaccinium type (EVT), Empetrum-Calluna type (ECT) and Vaccinium-Myrtillus type (VMT).

The Scots pine (Pinus sylvestris L.) sample plots represented variation of age classes for construction of mean development series. The Norway spruce (Picea abies (L.) H. Karst.) of the region are so old that development series could be obtained only for dominant trees based on stem analysis.

The average development of Scots pine stand on EMT type within the region is on average more rapid and the yield in cubic volume quantitatively larger and structurally better than that on ECT type. Self-thinning during the early decades of EVT is slower. The pine stands are denser in the age of 70 in Kainuu compared to Central Northern Finland, but the development and yield are similar.

The development, yield and structure of natural Norway spruce stand on VMT proved considerably inferior to the average level of pine stands on EVT, and to a major part on ECT. The mixed pines on spruce sample plots have developed better than spruces of equal age. Spruce stands on VMT in the area developed markedly better than Geranium-Dryopteris-Myrtillus (GDMT) in Central Northern Finland.

It seems that a spruce stand seems to require more fertile site type in north than in the southern part of Finland. These fertile types are relative rare in the north. In the region, the best results are received with pine. As a rule, also the yield of birch (Betula sp.) is poor in the region.

The PDF includes a summary in English.

• Ilvessalo, E-mail: yi@mm.unknown

The article is fifth part of a series of papers on fully stocked natural normal stands on mineral soils in Finland. This part studies the stands in Northern Lapland, dominated by Scots pine (Pinus sylvestris L.). This investigation was concerned mainly with Scotch pine stands, using Norway spruce (Picea abies (L.) H. Karst.) and birch (Betula sp.) stands for comparison only. 107 sample plots were measured.

The most common forest types in the area are Empetrum-Myrtillus-(Cladina) type, EM(C1), Ericacea-Cladinae type, ErCIT, P-L, and Cladina type, C1T. Stand development is more rapid and wood production greater in EM(C1) type than ErCIT, while the C1T stands are further behind in all respects. The average differences in stand characteristics between forest types are roughly similar, but for cubic volume and total production less, than between the more southerly forest types. Measurements made from increment cores taken at breast height have confirmed that variation of the pine annual ring width has on average been very considerable, in accordance with the climatic, mainly temperature, variations, in the investigation area close to the north pine forest limit.

The few plots from birch and spruce stands measured as samples in the northern Lapland investigation area indicate the generally poor development and wood production of these stands by comparison with pine stands.

The PDF includes a summary in English.

• Ilvessalo, E-mail: yi@mm.unknown

The article is third part of a series of papers on fully stocked natural normal stands on mineral soils in Finland. This part studies area between the ca. 62nd and 66nd parallels of the strip of land on the Gulf of Bothnia stretching from the coast to an altitude of 150 m above the sea level. The material consists of 121 sample plots in Scots pine (Pinus sylvestris L.) stands, 36 sample plots in Norway spruce (Picea abies (L.) H. Karst.) and 22 sample plots in birch (Betula sp.) stands.

Since the vegetation gradually changes from south to north, it was considered necessary to separate sub-types (marked s.) for certain southern-central forest types; these are poorer in vegetation but obviously more generally found than the main types. The Myrtillus s. sub-type shows slower development of pine stands than the Myrtillus type. The number of stems on the former is greater, owing to the slow initial development, but the mean diameter and height are smaller than on the latter. The difference in volume and growth increases with age. The slower the rate of self-thinning on the sub-type has the effect that the differences in total production are small.

The Vaccinium sub-type s. (VTs.) is poorer in vegetation than the southern-central type, differs from VT less than was the difference in the MT sub-types. The Empetrum-Vaccinium type (EVT) in general differs considerably from the VT but less from the VTs., in relation to which the difference shows mainly in the volume and total production. The EVT differs from the Calluna type as regards in all stand characteristics.

The results of this study suggest that the s.c. sub-type MT could be placed between the types MT and VT. This has significance especially in forest mensuration. However, in practical forest inventories it would seem possible to combine MT and MTs. to avoid having too many site classes. The types VT and VTs. can generally be considered nearly as one type. Similarly, CT and ECT (Empetrum-Calluna type) may be regarded as one site group. The differences may also partly be due to differences in early treatment of the forests.

The PDF includes a summary in English.

• Ilvessalo, E-mail: yi@mm.unknown