Current issue: 57(1)
Under compilation: 57(2)
A process-oriented tree and stand growth model is extended to be applicable to the analysis of timber quality, and how it is influenced by silvicultural treatments. The tree-level model is based on the carbon balance and it incorporates the dynamics of five biomass variables as well as tree height, crown base, and breast height diameter. Allocation of carbon is based on the conservation of structural relationships, in particular, the pipe model. The pipe-model relationships are extended to the whorl level, but in order to avoid a 3-dimensional model of entire crown structure, the branch module is largely stochastic and aggregated. In model construction, a top-down hierarchy is used where at each step down, the upper level sets constraints for the lower level. Some advantages of this approach are model consistency and efficiency of calculations, but probably at the cost of reduced flexibility. The detailed structure related with the branching module is preliminary and will be improved when more data becomes available. Model parameters are identified for Scots pine (Pinus sylvestris L.) in Southern Finland, and example simulations are carried out to compare the development of quality characteristics in different stocking densities.
In the literature review the current status of information on the genetic variation of CO2 exchange and some reviews and investigations on this subject are listed. Photorespiration is separately discussed and unpublished data of an electron microscope study of poplar leaf microbodies are presented.
Considerable genetic inter- and intraspecific variation is found in several characteristics that affect CO2 exchange in trees. Photosynthesis in young trees does not correlate well with growth through the whole rotation cycle. A special interest has been shown to marginal environmental conditions (e.g. water deficit, low temperature, and low light intensity), as opposed to optimal conditions often employed in laboratory studies of CO2 exchange in trees.
In an unpublished poplar studies by the author et.al. a preliminary experiment with poplar clones showed variation in the CO2 competition point. This variation was negatively correlated with the photosynthesis efficiency of these clones.
The PDF includes a summary in English.
The purpose of the study was to find out the most economical fuel for central heating boilers in different parts of Finland. The most common central heating fuels and boilers used in Finland were compared in the study.
The present consumption of different fuels and the regional distribution of the boilers of a few main types was investigated. The costs were calculated according to the costs level of February 1957. To be able to compare the costs, both variable costs and fixed costs were calculated. The heat output produced annually in the different boilers was studied to divide the fixed costs into costs per heat unit.
Comparison of the total costs per heat unit showed that cost of wood or imported fuels (oil, coke, coal etc.) was about on the same level in the coastal areas close to import harbours, but wood was the cheapest fuel for central heating in inland.
The article includes an abstract in English.
The government of Finland appointed a committee to make a suggestion of measures to be taken to arrange fuel supply during the heating season. The committee drafted also a plan to regulate and govern the fuel economy.
The committee estimated that the total consumption of coal, coke, firewood, waste wood and fuel peat, converted into pine firewood increased from 33.8 million eu.m in piled measure in heating period of 1952-53 to 42.9 million in 1955-56. According to the report, the demand of fuel is met increasingly through imported fuels, such as coal, coke and oil. The change is mainly due by their lower price and technically easy handling compared to domestic fuels.
The committee suggests that the production of domestic fuels, peat and firewood, should be increased and rationalized. In addition, financial support should be targeted to construct hydroelectric plants. Fuel peat industry should be developed further. The use of oil should be promoted, and boilers able to use different kinds of fuel should be constructed. To be prepared in changes in international situation, stocks of fuel are needed.
Fuel shortage during and after the Second World War compelled the Government of Finland to improve the fuel supply. In 1948 the Government appointed a Committee to draft a proposal on use of domestic and imported fuels. Special attention was placed on how to develop use of peat as fuel.
In rural districts, firewood billets and waste wood accounted for 45% of fuel consumption. For other users than the rural population, coal and coke consisted 25%, industrial waste wood 11% and billets 18% of the total consumption in 1938. After the war the use of coal and coke increased and the use of billets decreased.
Due to the decreased demand of billets, their price in the towns fell lower than the production and transport costs from the most remote areas where the wood was harvested. The demand for small sized timber is important for silvicultural reasons, and wood harvesting creates jobs for the rural population, therefore, the Committee proposes that the state supports the production of billets. This could be done by improving the effectiveness of firewood loggings, and by building truck roads and railways.
Small-sized birch is used predominantly as fuel. The Committee considers the growing stock of birch to be the largest unutilized wood reserve. Supported by technological research, it may become a new raw material for sulphate cellulose industry. Use of industrial waste wood as fuel and improvement of heating equipment would improve the competitiveness of fuelwood and peat against other fuels. For the possible interruptions in imports, stocks of foreign fuels should be maintained.
The article includes a summary in English.
Silva Fennica issue 52 includes presentations held in professional development courses, arranged for foresters working in public administration in 1938. The presentations focus on practical issues in forest management and administration, especially in regional level. The education was arranged by Forest Service.
This presentation describes the principles of charcoal burning in Finland at the time when charcoal had found a new market in ore processing.
The use of imported fuels has increased in Finland, which has resulted in a growing disregard of domestic fuels, primarily firewood, on fuel market. This has affected forest management and economy of forest owners as well as diminishing the working opportunities in the countryside by decreasing the demand of small-sized timber. This investigation studies the fuel problem in the industrial field by a survey sent to all industrial plants in the country.
The different fuels were converted to the calorific value of pine firewood measured in piled cubic meters (p-m3, cu.m.). In 1950 the industry utilized 14.1 million cu.m piled measure of imported and domestic fuels. Of this 47% was domestic fuels and 53% imported fuels. The share of coal was 40%, wood waste almost 30%, and firewood 18%. The relatively small proportion of firewood suggests that it could be possible to increase the industrial demand for firewood. However, it should be noted that industry uses fuel mainly for power production, where imported fuels are highly effective. Forest industry used 2/3 of all domestic fuel.
According to the report, waste wood was cheapest kind of fuel for industry. It was, however, often the plant’s own waste material. The cost of coal at the mill was 60% of the corresponding price of firewood. The location of the industry affects greatly the price relations between domestic and imported fuels. Coal is cheaper close to the harbours and the coastline of the country. The state has supported firewood transportation by lower freight rates for firewood.
The PDF includes a summary in English.
Plants assimilate carbon dioxide from the air. Respiration of plants also produce carbon dioxide. Because the carbon dioxide level of the air is only 0.3%, only little carbon dioxide can diffuse in plants. Thus, the carbon dioxide assimilated by the plants is formed mostly in the earth when organic substances are degraded. The article describes a method to measure carbon dioxide level in the air.