Silva Fennica no. 117 | 1965

According to the statistics, the fuel wood consumption in Europe has declined since 1925/1929, when the total fuel wood consumption was 144 million m³. In 1960 the consumption was 108 million m³. Because of insufficient statistics in the early years, the drop may even be larger than shown by the figures. The aim of this paper is to assess what part of European fuel wood removals in 1960 could be used for industrial purposes by 1975.

It was estimated that in 1975 the use of fuel wood in Europe will be about 45–55 million m³ less than in 1960 and about 10 million m³ of this amount will consist of coniferous species. It is believed that about 45 million m³ could be transferred to industrial use by 1975, and 55 million m³ is supposed to be the maximum reduction achievable by 1975. The estimates are based on the revised European fuel wood removal figures.

The new European timber trends and prospects study reveals a shortage of small-sized coniferous wood of about 25–43 million m³, depending on whether the exports from Europe are curtailed or not. The decrease of coniferous fuel wood of 10 million m³ could almost entirely be transferred for the use of industry.

A more important question is, is there demand for the extra small-size broadleaved wood. It is important to note that there is no longer any technical limitations on the use of this kind of wood for producing pulp, paper paperboard and wood-based panel products.

Fuelwood is often collected by the farmer and used near the farm. If the wood is to be used in the industry, harvesting and transport costs need to be decreased. However, productivity of the logging and transportation may be significantly improved by cutting the trees into longer lengths and professional harvesting. About 40% of the potential transfer of fuelwood to industrial uses is concentrated in Finland (7 million m³), France (5 million m³), and Italy (7 million m³). Other countries with significant potential shifts could be Romania, Spain and Yugoslavia.

The PDF includes a summary in French, German, Dutch, Russian and Finnish.

• Roitto, E-mail: yr@mm.unknown

When the seed harvest of Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) H. Karst.) are low, pine and spruce buds are among the secondary food items of squirrel (Sciurus vulgaris L.) in Finland. In this study, conducted in Nokia in Southern Finland in 1962-1963, eating of pine buds by squirrel is described. The eaten buds in 15-years old Scots pine seedlings were recorded in two seedling stands.

According to the results, the squirrels selected the largest buds of the best seedlings in the studied stands. In over 50% of the cases the squirrels chose only the buds of the leading shoot, especially the terminal bud. In half of the trees, a side bud of the leading shoot continued the growth, which causes form defects in the trees. In 35% of the damaged trees, a lateral branch continued the growth. Well-growing seedling stands may be especially susceptible for damages caused by, for instance, squirrels.

The PDF includes a summary in Finnish.

• Pulliainen, E-mail: ep@mm.unknown
• Salonen, E-mail: ks@mm.unknown

Understanding the growth of trees is the prerequisite for meaningful forest management. Hence the studies on the ways the trees grow is important. The growth of roots and sprouts was studied by Larix leptolesis, Pinus silvestris, Betula pendula, Robinia pseudoacasia, Populus euramericana, Pseudotsuga taxifolia, Quercus borealis and some other species. The results of still ongoing experiments on pine, birch and larch are presented for root and shoot growth.

The results indicate that the amount of light or shade the tree is having plays an important role in the growth. Hence some tree species are better adapted to shade than others, there are differences in their growth depending whether they are in light or in shade. 

• Lyr, E-mail: hl@mm.unknown
• Hoffmann, E-mail: gh@mm.unknown

The many unsolved questions concerning fertilization makes it difficult to forecast accurately its biological and economic consequences. Some of the problems are discussed in this paper. The most common types of forests in Sweden, Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) H. Karst.) stands on well-drained mineral soil, respond strongly to nitrogenous fertilizers, but the effect of phosphate, potash or lime is small or nil, at least within 5–10 years after application. The response of nitrogen lasts 4–5 years in pine and somewhat more in spruce.

Drained peatlands usually respond to mineral fertilization, but the improvement brought about by a PK application depends, inter alia, on the nitrogen content of the peat. Peatlands with a peat low in nitrogen need NPK fertilization. For deep peatlands, a moderate or high nitrogen content, a single PK application improves growth conditions for a very long time. Experience of fertilizing shallow peatlands and poorly-drained mineral soil is very limited, but it seems easy to get a growth response either with nitrogen alone or with NPK.

The results of fertilization at the time of planting have not, as a rule, been very good in Sweden. An exception is the afforestation of abandoned fields on drained deep peat, where PK fertilizer around the plant seems to be essential for both survival and growth.

• Tamm, E-mail: ct@mm.unknown

The Economic Council asked Heikinheimo, Holopainen and Kuusela to prepare a report on the development of Finland’s forest resources up to the beginning of the next century. The expansion of forest industry beyond the level foreseen in earlier forecasts, the large-scale removal and neglect of the basic improvements required have weakened the condition of the wood production to such an extent that extensive measures are needed to ensure the continuity of the supply of wood. The results of the calculations are formed in three separately analysed alternatives.

Alternative I: Realisation of the Teho programme and the removal corresponding to it. The development of the growing stock according to the programme would only permit a cut amounting to an annual drain of ca. 51 million m³ up to the year 2000. After that it would be possible gradually to increase the removal. This drain would not itself to utilise fully the already existing production capacity of the industry.

Alternative II: Consequences of the predicted removal if the Teho programme is realised as such. The wood utilization forecast based on the premises given to the team show that the annual drain will grow in 1964–1975 from 52 to 58 million m³, and thereafter by 0.5% annually. This would lead to over-cutting, and exhaust the present growing stock by the turn of the century. If annual total drain of ca. 58 million m³ would after 1975 be sufficient, exhaustion of the growing stock would be postponed for 4–5 years.

Alternative III. Teho programme expanded in conformity with the removal forecast. A new programme is proposed, which includes, among others, large scale fertilization of fully grown firm forest land at about the rate of 100,000 ha/year, intensified artificial regeneration, assurance of the supply of planting stock and seed, increase of forest drainage from the present 155,000 to 250,000 ha/year by 1970, site preparation of the cutting areas for artificial regeneration, increase of tending or seeding stands to 300,000 ha/year, replacement of fuelwood by other fuels, increase of wood import and new forest roads.

• Ervasti, E-mail: se@mm.unknown
• Heikinheimo, E-mail: lh@mm.unknown
• Holopainen, E-mail: vh@mm.unknown
• Kuusela, E-mail: kk@mm.unknown
• Sirén, E-mail: gs@mm.unknown

The present study is an attempt to clarify the decrease in growth, or the increment loss, caused by sudden reduction of growth of the growing stock below a certain level, and to find a method for its determination. Increment loss is defined as a decrease in growth during the rotation due to a deficient stock volume. The material consists of Koivisto’s yield tables for repeatedly thinned stands in Southern Finland, and the results of the Third National Forest Inventory concerning the mean volume and increment in the productive sites.

For the calculation of increment loss three formulae were constructed where the increment loss is calculated 1) as the difference between the removal by thinnings in normally developed stands during a time equal with the period of deficient stock and the suddenly removed stock, 2) according to the compound interest calculation principle as the sum of the differences which are obtained by subtracting from the removal in each thinning during the period of deficient stock its initial value, and 3) as the straight interest of the stock deficiency during the period of deficient stock.

According to the calculations, the increment loss is greatest in stands to be grown, viz. 50 m³ solid measure excluding bark per hectare tended Norway spruce stands on Oxalis-Myrtillus type sites at 40% deficiency below minimum stock. In stands to be regenerated the losses are, too, greatest in the similar stands. It exceeds 200 m³/ha when stands younger than 50 years have to been regenerated and the removal amounts to 50% of the stock. In stands to be regenerated the increment loss for spruce, due to the slow initial development by the species, is greater than for Scots pine and birch. The loss is the same at different period of age if the relative deficiency of the stock is of equal size.

According to the study, each stand has a characteristic variation in the increment loss which depends mainly on the relative degree of deficiency from the minimum stock. The formulae and methods can be used to determine the increment loss in average and better stands in Southern Finland when the stock suddenly decreases.

The PDF includes a summary in English.

• Matilainen, E-mail: tm@mm.unknown