Articles containing the keyword 'natural normal forests'

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