Current issue: 58(4)
Seed mass within any plant species is one of the least plastic components of plant structure. The aim of this study was to analyse the variation in the seed mass of Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) H. Karst.) in relation to three environmental factors: soil fertility, mean temperature and precipitation during seed filling period. Data published earlier on seed mass of these species on different sites and different years was used in the study.
The seed mass of both species was independent of soil fertility (forest type) but did vary between different years. It is hypothesized that if the seed-ripening summer is warmer than average, Scots pine seed mass tends to be smaller. In this study, seed mass varied independently of the amount of precipitation during the ripening summer. However, generalization of the results requires further study.
The PDF includes an abstract in English.
The development of shoot number and shoot properties was examined in successive shoot cohorts of young widely-spaced Scots pine trees (Pinus sylvestris L.) growing in a progeny trial. This was accomplished by reconstructing the branching process of the trees over a period of five years, from tree age 4 to 8. During this time the number of shoots in successive shoot cohorts increased rapidly, while at the same time the mean shoot length decreased. The decrease in shoot lengths from older to younger shoots was accompanied by a decline in the bifuraction frequency of the shoots. In general, rapid changes occurred in the branching characteristics during the yearly development of the trees. The variation in the branching characteristics was reflected in the development of the architecture and biomass production of the trees.
The PDF includes an abstract in Finnish.
The Academy of Finland commissioned a review of forest regeneration research. This paper summarises the evaluation. The report deals with the individual research projects and, in addition, the international evaluation group gives several recommendations to develop the forest regeneration research further. The recommendations concern education and training, publications, peer review, experimental design, routine work and extension service, and technology transfer. The paper also includes comments of the Finnish Forest Institute, the Finnish Society of Forest Science and a research scientist on the results of the evaluation.
The PDF includes a summary in English.
In 1979, the Federal Research in the United States instituted a so-called ”tight money” policy which led to a decrease in the demand for stumpage. The decrease in demand brought about lower stumpage prices and, consequently, a waning interest in policies to stimulate NIPF production. The authors report on five recent studies on NIPF behaviour and raise concerns that increases in demand for housing may bring new pressure upon NIPF as a source of wood.
Methods involving the use of moving averages, trend surfaces and their combination are compared in deriving local values of monthly mean temperatures and precipitation sums from the observations made by the Finnish Meteorological Office. Correlation between meteorological variables and sea index, lake index and height above sea level were used in the trend surface method and in the combined method. Combined method, with a trend surface calculated from means of a long time period, was the most reliable method to estimate long local time series.
A method to calculate unbiased estimates of effective temperature sums from monthly mean temperatures is presented.
The PDF includes a summary in English.
The study is part of a project designed to elucidate the nutrient budget of a Scots pine (Pinus sylvestris L.) stand. Results of variation in the nutrient contents were compared with those obtained for the previous growing season.
The potassium and calcium contents varied the greatest in the humus layer. However, in the bottom and field layer vegetation and needles the variation in the nitrogen content was the greatest. The nutrient contents of the needles were affected by the physiological stage of development, needle age and the position in the crown of the tree. The nutrient content of the rainfall increased in the order: free rainfall, throughfall, and stem flow.
The PDF includes a summary in Finnish.
This study forms part of a project designed to elucidate the total nutrient budget of a Scots pine (Pinus sylvestris L.) stand in Central Finland during the 1974 growing period. Precipitation has been divided up into precipitation, throughfall and stemflow.
The acidity of the rainwater was found to increase in the order – Precipitation, throughfall and stemflow. The electrolyte content of the rain water from throughfall and stemflow was higher than that of precipitation. The nutrient contents of precipitation were rather low. Throughfall and stemflow were found to leach some nutrient from the trees. This was most clear in the case of potassium. The total amounts of nutrients reaching the ground in throughfall were found to be smaller than those in precipitation. On the other hand, the amounts of potassium, calcium and magnesium in stemflow were clearly greater than those in precipitation.
The PDF includes a summary in English.
The aim of the paper was to study the amount and distribution of rainfall in a virgin Norway spruce (Picea abies (L.) H. Karst.) stand. Special attention has been paid to the dependence of throughfall on the characteristics of the precipitation falling on an open area and the stand.
The throughfall was 62% of the precipitation in the open. The best independent variable as regards the throughfall was the amount of precipitation falling in the open. The heaviness of precipitation in the open gave no meaningful correlation. Horizontal layout of the stand was found to have some effect on the throughfall. The throughfall was also influenced by the tree species composition of the stand. Only 52% of the total variance of the amount of water caught by the rain gauges could be predicted with the characteristics of the precipitation in the open and the stand.
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The significance of water budget in June and July for forest and peatland vegetation, and consequent effects on fauna, climate and agriculture has been studied.
In June, the difference between evaporation and precipitation is greater than it is later in the summer. North of the line zero difference of evaporation and precipitation, coinciding with a line of sharp change in forest vegetation, the uppermost part of podsol remains wet throughout the summer. During July, the line of zero difference moves from north to south over the greater part of Finland, run-off being minute and podsol at the driest in this month. This line, indicating the length of the period with evaporation greater than precipitation and causing a sharp change in forest vegetation, in frequency of peatlands, amount of growing stock productive capacity of forests etc. This line is significant also for cultivation: because of the lower evaporation north of this line, night temperature below the freezing point often appear in summer.
The PDF includes a summary in English.
The purpose of the study was to measure the throughfall in a managed Scots pine (Pinus sylvestris L.) stand in Southern Finland (61°47’, 24°18’). Totally 20 summer rain gauges (collecting area 100 cm2) were placed randomly in form of a lattice of 100 squares, each 2x2 m. Six rain throughs, 15 cm x 150 cm, were placed in the experimental stand. Auxiliary precipitation measurement was done in an opening, by using four summer rain gauges, two rain throughs and one recording rain gauge. The throughfall was followed in May–September 1967.
In comparison with summer rain gauges, the rain throughs gave too low values when the precipitation was below 3 mm/rain shower. Accordingly, only the results of rain gauges were used. The rate of throughfall was determined by the amount of precipitation and the rate of heaviness of the rain shower. When trying to describe the relative amount of throughfall by using various characteristics of the stand, the equitation proposed by Seppänen (1964) proved the best. When the rate of throughfall was depicted with the distance between the summer gauge and the nearest tree, there was negative correlation between these. The correlation was negative under heavy rains, but positive in small rains.
Various factors of uncertainty are discussed. During long periods the areas under Scots pine canopies reach more rain water than those between the canopies, which may be important when analysing the spatial distribution of ground vegetation.
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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.
The aim of this treatise is to describe forests owned by timber companies, their area and position, the quality of forests, the condition of the forests, and fellings carried out during the World War II.
Area of the company-owned forest was 1,95 million hectares, 1,64 million hectares of which was productive and 0,31 hectares inferior forest soil, not including the areas lost after the war. Most of the forests were situated in remote regions. Average volume of the tree stands was slightly larger than in farm-owned forests. Fellings counted for 84% of the growth of the forests.
During the war the state set felling quotas for both company, private and state forests. It was widely discussed how well they were met by the different owner groups. According to the statistics, the companies had followed relatively closely their cutting plans in peace years. Cuttings were highest in 1939, when the war begun. In the war years 1940-43, lack of workforce, horses and cars for transport complicated logging. The fellings increased again during truce after Winter War. Especially demand for small timber increased during the war. Felling of firewood increased in all the owner groups, in particular in the private forests that were situated near settlements. in general fellings were higher in forests that were easiest to reach.
During the war the companies acquired timber more from their own forests. The fellings from company forests were in war years 70% of those in peace years. The article concludes that companies fulfilled the requirements as well as it was possible in the circumstances.
The article includes an abstract in English.
A Committee was appointed in 1931 to prepare a program to improve the trade of small timber and to develop Finnish fuels and their production. The low demand for small timber is caused by the reduced export of Egyptian balks, and decreased demand of fuel wood that have been replaced by the imported fuels, like coal. At the same time, the supply of small timber has grown significantly due to increased thinnings, and better transport facilities that have made timber more accessible. Also, decreasing demand of large timber has increased the supply of small timber. The demand of small timber concentrates on Norway spruce (Picea abies (L.) H. Karst.). The sales of small timber are crucial from the silvicultural point of view. Selection felling of large timber in the past has reduced the supply of logs and led to surplus of small timber.
The article discusses the uses of small timber and potential new fields, such as wood sugar as fodder or refining wood as fuel. The use of timber should be promoted especially in the domestic industry. The Committee suggests funding for an additional forestry teaching post in the University of Technology, for forest technology and forest economics research in the Forest Research Institute, for research in wood technics, and for follow-up of forest sugar and wood gas fields.
The PDF includes a summary in English.
Short run market forecasting is desirable both for adjusting production and for regulating the national employment policy. In this study a forecast is made for one product. The purpose of the study is to develop a short run model describing newsprint sales in Finland that will combine mathematical simplicity, accuracy of description and universality.
Two methods of selecting variables seemed to be available. According to the first, newsprint consumption is divided into components, each of which is considered separately. The second method, which proved more fruitful, starts out directly from factors influencing the publishers’ decisions in purchasing newsprint, eliminating the least significant intuitively and simultaneously determining the lags.
The models developed in this study are capable of forecasting potential consumption. Even the best models in this study are multicollinear. The further into the future a forecast is extended, the greater is the possibility that relationships between the explanatory variables will change. It is intended that the newsprint seller will profit from the models achieved by using them to forecast sales in a future period, so that he can avoid both loss of interest due to acquiring a surplus of raw material or acute shortages of raw material.
The PDF includes a summary in Finnish.
The present investigation is concerned with the price elasticity of sawn wood, concentrating on the price elasticity of sawn wood supply for export. The supply of sawn wood for export is referred to the joint attitude to price changes of all producers participating in the market.
The study concludes that producers cannot in the short- and medium-term view use the price parameter to increase total utilization in the sawn wood market. Demand holds a primary position in price formation. The capacity reserve of the sawmills permits great variations in output at the mill level, and thus elasticity in the supply of sawn wood. High timber costs are typical for the industry. Supply of roundwood can easily be adapted even to large variations in demand. The price elasticity of roundwood supply is rather great.
The long process of sawn wood production and the resulting relatively long lead-time of deliveries result in a long adaptation time of supply. Expansion and contraction of sawn wood exports cause, via the effect of exports, on income similar fluctuations in the domestic sales of sawn wood. This weakens the price elasticity of exports in some degree.
The ‘instantaneous elasticity’ upwards of sawn wood supply might be great, but speculation with stocks at the different levels of production often makes it ‘incalculable’. The price elasticity of a medium-long and long period can be expected to be relatively great upwards. The downward elasticity of a period of medium length is probably small. The elasticity of a prolonged period may be influenced by the substitution of other materials for sawn wood.
The PDF includes a summary in Finnish.
The purpose of the investigation was to examine the seasonal pattern in Finnish export shipments and export sales of sawn softwood in 1927-1953. Statistics concerning shipments have been obtained from the Board of Customs, and material relating to sales has been provided by the Finnish Sawmill Owner’s Association (now Finnish Sawmills Association). On the basis of original monthly statistics, 13-month moving averages were computed. Finally, a seasonal index was calculated.
According to the results, the export shipments have a fairly apparent seasonal pattern with very low figures from January to April, a peak from June to August, and thereafter a gradual decline up to the end of the year. There are also considerable variations from year to year but in general the exports follow this rhythm. In contrast to export shipments the seasonal pattern of export sales is characterised by significant irregularity. Market developments and speculation play a far greater role than the seasonal factors. Indeed, a seasonal character in export sales can scarcely be discerned.
The Acta Forestalia Fennica issue 61 was published in honour of professor Eino Saari’s 60th birthday.
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Finland was the first country, in connection with World War II, from which reparations were demanded. In September 1944 Soviet Union demanded indemnifications of 300 million dollars, payable in commodities (timber products, paper, wood pulp, sea-going and river craft, sundry machinery). Later similar obligations of deliveries in kind were applied to Rumania, Bulgaria, Hungary and Italy. Germany were to pay in kind for the losses caused by her to the Allied nations in the course of the war.
The article discusses the principle of war indemnities to be paid exclusively in kind, which was a new one, and compares it to the situation after World War I. One reason for the principle was a negative lesson drawn from the experiences after the previous war. A reparation system of payment in kind is the most suitable system for a country like the Soviet-Union, as it requires, at least some degree of economic planning by a centralized system.
The Acta Forestalia Fennica issue 61 was published in honour of professor Eino Saari’s 60th birthday.
The article revises the accomplishments of professor Peter Woldemar Hannikainen, the former director of Forest Service of Finland, in the development of forest sector in the end of 1800s and beginning of 1900s.
The PDF includes a summary in German.
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.
In the present investigation, the problems connected to demand of firewood are dealt with by studying the fuel markets of the three biggest towns in Finland – Helsinki, Turku and Tampere as well as those of Vaasa. The purpose of the investigation was to study the firewood supply areas in two time periods, in 1933-1939 and in 1945-1947, after the Second World War.
Railway and shipping were the most important ways for transporting firewood in 1933-1939. Towards the end of the period, road transport increased especially in Turku and in Vaasa. In 1945-47 almost 90% of the firewood transported to Helsinki, 60% to Tampere and Turku, and over 50% of the firewood transpors to Vaasa were carried by rail. One factor supporting rail transport was that the tariff policy of the State Railways gave preference to firewood transports.
The supply areas increased markedly from 1933-1939 to 1945-1947. Supply of firewood near the towns in the southern, southwestern and western parts of the country was small. Also, pulp industry began to use small-sized timber in 1930s, which increased competition of the wood. Coal and coke began to replace firewood in the 30s, but their use decreased during and after the war due to supply shortage.
The PDF includes a summary in English.
The purpose of the analysis presented in the article was to form an estimate as to future Finnish-American trade in forest products. The Finnish-American trade, that had its beginning in 1919, has been steadily growing and at the outbreak of the Second World War occupied third place in Finland’s total foreign trade. Over 90% of the Finnish exports consisted of forest industry products, pulp and newsprint being the most important items. The sales associations of the pulp and paper industries made it possible for the industries to gain a footing in the American market.
The production of pulp and most kinds of paper has increased in the USA up to 1942, but production of newsprint has tended to decrease. The timber resources of the country are large, but there is a considerable timber deficit in the northeastern states, therefore, these regions must be the principal aim for a campaign to build up the future market. According to the survey of future need of imports to the USA, more than two million tons of pulp and 2-3 million tons of paper products are needed in the immediate post-war period. The Canadian and Swedish competition will remain at about the same level, but one Finnish advantage, the quality, has disappeared on account of the progress made by research in the USA during the war.
The PDF includes a summary in Finnish.
Forest work in Finland has generally been paid by the job. The wages in 1930s were based on variable measuring units and principles in different parts of the country. The rates did not often take into account how difficult the individual stands are to harvest. The studies have shown that the productivity of logging depends on size of the stems, density of the stand, branchiness of the trees, terrain and depth of snow cover. The article suggests a wage system which takes into account the differences of the cutting areas.
Wages of felling and hauling logs that are payed per the trunk or cubic meter should be adjusted so that the earnings of an employee depends not on the quality of the stand. The quality of the stand influences the stumpage price of the wood, because of the versatile harvesting costs. If the demands of the job in a challenging stand are not compensated for the workers, the higher harvesting costs are inequitably balanced by lowering the wages of the forest workers.
The PDF includes a summary in German.
Factors determining newsprint consumption in Finland in 1960–1986 were analysed. An econometric recursive multi-equation model describing the structure of the newspaper industry was formulated and estimated to obtain information on direct factors influencing newsprint demand. Short-term and long-term demand elasticities for newspapers and newspaper advertising were estimated.
The results indicate that the main factors affecting newsprint consumption are total circulation of newspapers, volume of newspaper advertising and the change in newsprint substance weight. Total newspaper circulation was found to depend on the rate of household formation and real household income changes. Demand for newspapers was shown to be price-inelastic. Structural analysis indicates that income elasticity of newspaper demand has increased slightly over time.
The volume of newspaper advertising was shown to affect newsprint consumption via the effects on pagination. Newspaper and television advertising were found to be independent of each other. The impact of the reduction in the basis weight was found to be substantial. The estimation of long-term elasticities of demand for newspapers and newspaper advertising using dynamic models revealed that demand rigidities exist.
The case study of Finland proposes three reasons why newsprint demand has not shown clear signs of reaching a saturation level. First, although population growth has stagnated in major consuming countries, the number of households has been increasing continuously. Second, income elasticity of newspaper demand does not show a declining trend. Third, the main driving force behind the buoyant demand is the resurgence of demand for newspaper as an advertising medium. In forecasting newsprint consumption, in addition to projections of economic growth, attention must be paid to the rate of household formation, the development of the advertising sector, the factors affecting competition between alternative media and the resulting media-mix in advertising, and changes in the substantial weight.
The PDF includes a summary in Finnish
The study examines the factor demands of the Finnish pulp and paper industry. In the theoretical part of the study, factor demand equations are derived using neoclassical production theory. In the empirical part, econometric factor demand model is estimated using annual time-series data for the period 1960–86. The relationship of factor demands and their prices are examined in terms of own price, cross price and substitution elasticities.
It is assumed that the ”representative firm” in the pulp and paper industry is minimizing its costs of production at a given output level. In addition, a number of other assumptions are made which enable the production technology to be represented by a cost function, in which the inputs are capital, labour, energy and raw materials. From the cost function, the factor demand equations, i.e., the cost share equations are derived by applying Shephard’s lemma. The equations are transformed to estimable form using translog approximation for the underlying factor share functions.
The study differs from the previous factor demand studies by applying the error correction model based on the Granger Representation Theorem and the results of the cointegration literature to model the dynamics of the factor demand. This approach provides a statistically consistent method for estimating the long-run static factor demand equations and the corresponding short-run equations. In general, the econometrics of integrated processes (e.g. stationarity and cointegration tests) applied in the present study have not been applied before in factor demand systems models.
The empirical results of the study indicate that the error correction approach can be applied to estimations of the factor demands for the pulp and paper industry. In both industry sectors, the adjustment to short run disequlibrium (price shocks) appears to be fairly rapid. The most significant results of the calculated elasticities are that the factor demands of pulp and paper industries clearly react to changes in factor prices and that there are significant substitution possibilities between the different inputs. The absolute values of the elasticities are, on average, somewhat larger than have been obtained in previous studies.
The PDF includes a summary in Finnish.
Evaluation of product attributes and the overall quality significantly affect consumer purchasing decisions. Previous studies on wooden products have mostly addressed wood product quality from technical viewpoints, while largely disregarding environmental, social, and economic aspects in the assessments. Therefore, knowledge on how sustainability aspects are evaluated as a feature of wood product quality is narrow. This study investigated consumer perceptions of different quality indicators (i.e., quality cues and attributes) of wooden interior products with a special focus on sustainability and value chain phases. In addition, the connections between consumers’ sociodemographic background and their perceptions of the quality features of wooden interior products were evaluated. The material of the study was based on data gathered in 2018 with a postal survey sent to 1000 people living in Finland with a response rate of 25.6%. As methods of analysis, exploratory factor analysis, the Mann-Whitney U test, and the Kruskall-Wallis test were utilized. The results show that the quality indicators of wooden interior products can be grouped into four factors relating to products’ environmental friendliness, fit with lifestyle and home design, visual and tactile attractiveness, and technical solidity, which are in multiple ways connected with sustainability. The sociodemographic background of the respondents was found to be linked with consumer scores for those factors. Engaging consumers in sustainable consumption choices requires providing them with information on wooden product value chains that meets their individual needs in relation to their existing knowledge of those issues and individual values.
Thekopsora areolata (Fr.) Magnus is a serious cone pathogen that reduces seed crop of Picea abies (L.) Karst. and other Picea spp. Natural sporulation of T. areolata was investigated in nine Norway spruce seed orchards suffering from severe successive T. areolata epidemics in Finland. Habitats occupied by Vaccinium myrtillus L., V. vitis-idaea L., Empetrum nigrum L. and Calluna vulgaris (L.) Hull, and a number of other wild species belonging to ground flora were investigated for Thekopsora areolata uredinia 9–10 times in May–September 2018–2019. Occurrence of Thekopsora uredinia was estimated in current-year leaves of the plants in ca. 25 sample plots of 1 m2 in each seed orchard. A sample of plant leaves with rust uredinia or necrotic pustules were collected from each plot. No rust fruiting stages of T. areolata were found on any of the test species of ground flora. However, rust uredinia were observed regularly on leaves of V. myrtillus and V. vitis-idaea in all seed orchards between mid-July and the end of September. Rust sporulation started on V. myrtillus in July and on V. vitis-idaea in August. Based on symptoms, uredinia and spore morphology, the rust on both V. myrtillus and V. vitis-idaea was identified as blueberry rust, Naohidemyces vaccinii (Jørst.) S. Sato, Katsuya & Y. Hirats. ex Vanderwegen & Fraiture. The uredinial stage of the rust on Vaccinium spp. were described. No evidence of natural sporulation of T. areolata on wild plant species other than Prunus was observed in Finnish Norway spruce seed orchards.
The alternate host range of cherry-spruce rust is poorly studied although such information could be important in protecting spruce seed orchards from infections. Pathogenicity of cherry-spruce rust, Thekopsora areolata (Fr.) Magnus, was investigated on potential alternate host species in a greenhouse and in a laboratory in Finland. Five common species of Ericaceae, Vaccinium myrtillus L., V. uliginosum L., V. vitis-idaea L., Empetrum nigrum L. and Arctostaphylos uva-ursi (L.) Spreng, were inoculated in the greenhouse using aeciospores from seven Norway spruce [Picea abies (L.) H. Karst.] seed orchards suffering from T. areolata in 2018. In addition, young detached leaves of Vaccinium spp. and 17 other plant species of ground vegetation from eight Norway spruce seed orchards were inoculated with aeciospores from six seed orchards in the laboratory in 2019. Also, young leaves of Prunus padus L. trees growing within the seed orchards or close to them were inoculated as controls. None of the inoculated leaves of the potential alternate hosts formed uredinia either in the greenhouse or in the laboratory. In contrast, leaves of P. padus from the seed orchards were infected by the six spore sources from six seed orchards and produced uredinia. As T. areolata spores were able to infect only P. padus, but not the other tested species belonging to ground flora, it was concluded that T. areolata disperses only via Prunus spp. in Finnish seed orchards.
Cherry-spruce rust caused by Thekopsora areolata (Fr.) Magnus is a serious cone pathogen of Norway spruce [Picea abies (L.) Karst.]. The rust causes great economical losses in seed orchards specialized in the production of high quality seeds. Germination range of T. areolata aeciospores from rust populations (spore sources) in seven Finnish Norway spruce seed orchards was tested on water agar and malt agar at nine temperatures varying between 6–30 °C. The temperature range of spore germination was high varying between 6 °C and 27 °C, while germination was retarded at 30 °C. The peak in germination rate of all spore sources occurred between 15–24 °C. In a model with fixed effects of agar media, temperature and spore source, temperature had the most significant effect on germination. Spore source had a less significant effect, while agar media had a non-significant effect on germination. The rust was able to germinate at low temperatures corresponding to temperatures when the thermal growing season starts at 5 °C in the spring. As spores from cones from both the spruce canopy and the ground showed very similar germination ranges, it indicated the great capacity of all spores of the rust to germinate early in the spring. Hot temperatures with over 30 °C drastically reduced germination of the rust.
Two different pulse density airborne laser scanning datasets were used to develop a quality assessment methodology to determine how airborne laser scanning derived variables with the use of reference surface can determine forest road quality. The concept of a reference DEM (Digital Elevation Model) was used to guarantee locally invariant topographic analysis of road roughness. Structural condition, surface wear and flatness were assessed at two test sites in Eastern Finland, calculating surface indices with and without the reference DEM. The high pulse density dataset (12 pulses m–2) gave better classification results (77% accuracy of the correctly classified road sections) than the low pulse density dataset (1 pulse m–2). The use of a reference DEM increased the precision of the road quality classification with the low pulse density dataset when the classification was performed in two-steps. Four interpolation techniques (Inverse Weighted Distance, Kriging, Natural Neighbour and Spline) were compared, and spline interpolation provided the best classification. The work shows that applying a spline reference DEM it is possible to identify 66% of the poor quality road sections and 78% of the good ones. Locating these roads is essential for road maintenance.
Extant populations growing in regions that were refugia during the last glacial period are expected to show higher genetic diversity than populations that moved from these refugia into new areas in higher latitudes. Such new populations likely faced harsher climatic conditions, being established with reduced population size and experiencing the effects of genetic bottlenecks. In this study we employed data from nuclear SSR markers for detecting molecular signatures of genetic bottlenecks, and germination experiments to evaluate reduction of populations’ fitness in natural populations of Luehea divaricata Mart. et Zucc., growing in the southern range of the species distribution (around 30°S latitude). Signatures of genetic bottlenecks and reduction of populations’ fitness were observed in all populations. Lower levels of observed heterozygosity are correlated with populations’ fitness, decreasing germination capacity and increasing the proportion of anomalous germinated plantlets. Promoting the connection among populations is proposed as a key strategy towards conservation of L. divaricata genetic resources in its southernmost distribution range. The offspring from crosses among populations would significantly increase the observed heterozygosity and fitness of multiple populations.