Acta Forestalia Fennica vol. 69 | 1959

Since Finnish professor A.K. Cajander published his theory on forest types, there have been discussion and contradictory studies on certain forest types. This paper is a litterature review on the thick-moss type in Northern Finland and its parallel types in Kainuu and Southern Finland. First, the principles of Cajander’s theory on forest types is described and discussed. It is concluded that Cajander has described forest site types as their common, genuine variants. Borderline variants have been excluded from the description. 

Second, the North Finnish thick-moss type (Hylocomnium-Myrtillus type, HMT) and its position in Cajander’s system is discussed. Concepts of this forest type have varied considerably, and it has been argued that the type does not fit Cajander’s system very well, as it arises as a result of the invasion of other forest types by Norway spruce (Picea abies (L.) Karst.) with consequent degeneration of the site.  

The writer concludes findings of the results of the previous studies about MHT and its relations to the Myrtillus type. Cajander in his system included the thick-moss type in the moist upland forests as a type whose vegetation is less exacting than that of the Myrtillus type. This position seems to be the right one. Some factors point out the moist nature of HMT: the ability of Norway spruce to compete, a relatively high persipitation, the humidity of the climate in general and the rather poor water percolation capacity of the moraine soil. The HMT sites are relatively poor. It is stated that the opinion that the thick-moss type is secondary state of development of the Myrtillus type has no plant sociological, ecological, mensurational or silvicultural foundation. The type is probably Finland's most dynamic forest type, but in the natural forest its dynamics are confined to such changes as are permitted within the same forest type. HMT must be described as three series of plant association types, which differ from another to some extent. 

The PDF includes a summary in English. 

• Keltikangas, E-mail: vk@mm.unknown

This investigation is part of series of studies aiming at defining the present condition and growing stock of drained peatlands. The studies were conducted in 1955–1957. The first part concentrates on the state of the areas, and second part the growth and volume of the stands.

Condition of the drained peatlands, a total of 45,224 ha, in Southern and Northern Finland, was studied occularly as surveys by stands. The stands to be studied were chosen randomly. Drainage effect of the areas proved to be relatively good especially in Southern Finland in private lands. In Northern Finland in the State forests, however, were many drained areas with poor drainage effect. Many of these were preliminary drainages that had not been continued. Others had too sparse drainage system, the planning was insufficient or the ditches had deteriorated. The need for supplementary draining should be considered. The condition of the ditches in old draining areas was relatively weak. This can be problematic especially in private lands. Therefore, the ditches should be planned in a way that minimizes the need for repair. The silvicultural state of the forests was poor, mostly because forest management, and sometimes regeneration had been neglected.

A total of 1,368 sample plots were measured to determine the growing stock of the studied stands. The country was divided in five climatic zones to determine local variations in the growth. The material covered large variation of peatland types. The growth of different spruce swamp types had increased close to the mineral soil sites, but especially in originally treeless or sparcely wooded stands the growth was still poor. In addition to fertility of the peatland type, the climate zone had strong effect on the volume of the stands when similar peatland types were compared. Tree species composition seemed to be strongly determined by the peatland type. Against previous understanding thickness of the peat layer had little effect on the growth of the trees, and shallow peat layer proved not to improve the drainability of a peatland.

The PDF includes a summary in German.

• Heikurainen, E-mail: lh@mm.unknown