Current issue: 58(5)
This paper comments on the article written by Simo Hannelius that is published in the same issue of Silva Fennica (Who is the non-farmer forest owner? Silva Fennica 14 no. 4). Hannelius suggests that researchers dealing with the behaviour of private forest owners should change their classification to agree with the concepts presented in the Farm Economy statistics, and that the recommended concept of farmer forest owner is understood as a forest owner who has taxable net incomes (state taxation) from farming. Other private forest owners would be classified as non-farmers. Veli-Pekka Järveläinen states in his opinion that when distinguishing a farmer and a non-farmer, the key criterion should be the profession, which has been proved to be an important parameter in behavioural research.
The landscape preferences and attitudes of inhabitants of Puolanka, north-eastern Finland, to the effects of silvicultural practice on the forest landscape were studied by a postal inquiry. The effect of silvicultural practice on the forest landscape was mainly negative. Birch (Betula sp.) stands and mixed coniferous and deciduous tree species were the most preferred by the Puolanka inhabitants. The landscape preferences were related to socio-economic background of the inhabitants. The quality of the living environment also influenced the preferences, since uncommon features in the living environment were favoured most.
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Crown and stem growth of young Scots pines (Pinus sylvestris L.) were studied in relation to photosynthate supply and light condition in a stand. The magnitude of needle and bud formation, and radial and height growth were to a great extent dependent on the photosynthate supply. However, in shaded conditions the growth of each characteristics was greater than expected on the basis of photosynthate supply. In the stem system this was especially apparent for height growth. Consequently, height growth was favoured at the expense of radial growth in shaded conditions. It also appeared that the basic density of wood was negatively related to both tree position and photosynthate supply.
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Variation of wood characteristics was studied in two mature trees of Betula pendula Roth and two of B. pubescens Ehrh. by stressing the interrelationships of some of the structural features, basic density and shrinkage. Correlation analysis revealed that basic density was related to some of the variables studied, viz: number of rings (age) and distance from pith, height from the ground, ring width, fibre length and double wall thickness. Multiple regression equation showed that age from pith and height from the ground explained 80% of variation of basic density in B. pendula. Two structural variables, viz: fibre wall thickness and ring width accounted for only 28% of variation of basic density in B. pubescens. No significant relations could be found between shrinkage and any of the wood parameters measured in B. pendula while some of the relationships were significant in B. pubescens. However, only 55% of variation of volumetric shrinkage was explained by two related factors, viz: basic density and moisture content while only 35% of variation of tangential shrinkage was explained by ring width and fibre width. Increase in fibre length was highly associated with the increase in fibre width, double wall thickness and vessel length in either species.
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The first Finnish paper on aspen (Populus tremula L.) was published in 1759 in Åbo (Turku). After this dissertation, numerous scientific and other articles and reports have been published. In this bibliography about 340 papers are listed. Most of the papers deal only with aspen or other species of the genus Populus. Besides these even those articles have been included which deal with other problems but contain some information on the features of poplars.
The titles are listed without any translation or classification. If an article has a summary, it is shown in the title.
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On the basis of a limited material, the drying of Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) H. Karst.) timber at room temperature decreased the thickness of the bark proportionally to the decrease in the moisture content. The decrease was the greatest in the middle portion of the trunk. In the spruce material, the decrease in bark thickness was exceeded by the shrinkage of the wood. During soaking, the bark thickness of both tree species decreased, too, contrary to the presupposed hypothesis. In both cases, the shrinkage was the greatest in the middle portion of the trunk. In the spruce material, the decrease in bark thickness was exceeded by the shrinkage of the wood. Possible explanation for the phenomenon is discussed.
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Snow and rime, attached to branches of conifers, seriously damaged forests in a region of 11,000 km2 in Southern Finland during a passage of two nearly occluded cyclones in 1959. The roles of different weather elements were studied by considering the variations occurring in them over this region and its surroundings. Damage occurred only inside an accentuated pattern of copious orographic precipitation. Precipitation only became attached to and retained on branches in such parts of the area where temperature varied on both sides of freezing point but did not exceed 0.6°C. Furthermore, damage only occurred in forests where rime formed (above a certain level and on sloping towards the prevailing wind).
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The paper consists of a report of a study tour made by Finnish forestry students, under the leadership of the author, to Harbin, Changchun, Peking, Nanking and Shanghai in December 1977. In addition, some earlier literature sources concerning forestry in China are briefly reviewed. The paper presents the general geographic characteristics of north-eastern China, as well as the vegetation zones and timber species of this region. Silvicultural methods and the main features of forest technology and forest industry are also discussed. The last chapters describe the forestry administration and current trends in forestry education and research in north-eastern China as observed during the tour.
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The applicability of MCPA- and 2,4,5-T-herbicides for use in the management of sapling stands and the possibilities of carrying out foliar spraying at an earlier date than at precent with smaller doses of the active ingredient were examined in this study. The results were obtained from foliage spraying experiments carried out in Central Finland in summer 1976. MCPA and 2,4,5-T were as effective as each other against deciduous tree species. However, MCPA was slightly more effective against aspen (Populus tremula L.) than 2,4,5-T. The spraying date had no effect on the mortality rate of aspen or birch (Betula pendula Roth and B. pubescens Ehrh.) There were only very slight differences between the results for different dosage levels. The damage caused to Scots pine (Pinus sylvestris L.) was very slight. The temperature conditions prevailing during spraying affected spraying effectiveness in such way that the mortality rate decreased during cold period.
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The paper reviews the past research in the five major subfields of business economics of forestry. Although the twelve doctoral dissertations in the discipline distribute evenly among the subfields, timber production economics has gained the major weight during the past 10–20 years. The new forest products market development requires the focus be shifted from pulpwood to high quality sawn timber production. Maintaining the current market share requires effective measures to control the wood costs. The article proposes nine research projects relating to these market demands.
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It was concluded on the basis of the anatomical investigations of four mature trees that Betula pendula Roth can be distinguished from B. pubescens Ehrh. using the number of bars per scalariform perforation plate as an identification factor. If the average number of bars is more than 17.6, the sample is probably from B. pubescens, and if less, from B. pendula. The accuracy can be slightly improved by using the vessel frequency as another factor.
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A material of 478 birch logs were measured. The horizontal diameter was on average larger than the vertical one, the difference increasing with the increasing diameter. The reason was supposed to be the effect of sweep and out-of-roundness of logs. The difference between the actual and nominal length increased with the increasing lengths, but decreased with increasing diameter.
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Samples that had extensive pith flecks, caused by the larvae of Dendromyza betulae (now Phytobia betulae E.Kang), were collected from two trees of Betula pendula Roth and two B. pubescens Erhr. The age of the trees varied from 45 to 56 years. The effect of larvae injury on the rays was studied. The width of affected rays in both species was more than twice that of normal rays. The height and frequency also increased considerably. When describing the anatomy of Betula species the pith flecks should be treated with caution in order to avoid confusion and misinterpretation.
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Dependence of the growth increase given by fertilization on different stand characteristics is examined in this article. The aim was to determine whether the volume growth increase can be accurately determined beforehand when fertilization is carried out on mineral soil sites at a dosage of 120 kg N/ha. The material consisted mostly on of mature stands ready for cutting, a total of 22 Scots pine (Pinus sylvestris L.) and 20 Norway spruce (Picea abies (L.) H. Karst.) stands. Increase in basal area, height quality class and basal area of the stand were found to best explain the increment and its increase in the regression equations calculated for different types of fertilizer and the control level.
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The proportions of needle and wood in current-year shoots in crown systems of young Scots pine (Pinus sylvestris L.) trees was studied. The proportion of needles out of the total shoot biomass increased according to the increasing number of the whorl counted from the apex. In the lower part of the crown system the needle biomass of newly-formed shoots was 50–60 fold compared to that of wood and bark biomass. In the upper part of the crown system the same ratio was 1–2. The variation in ratio between needle and wood biomass was whorl-specific and independent of tree class. The magnitude of the ratio was not related to the position of the tree in the stand nor to the prevailing light conditions within the state.
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The technique of double normalizing, i.e. normalizing the relative needle biomass and the length of the living crown system, is applied to the modelling of the distribution of needle biomass in the canopy of young Scots pine (Pinus sylvestris L.) stands. The study based on the parameters of β-function shows that at the individual-tree level, the variance in needle distribution was not closely associated with any tree characteristics. A shift in the point of maximum needle biomass upwards unsuppressed trees was, however, evident. This was associated with an increase in the height of the trees. At the stand level, the stand mean height and stand density had an equal and a rather high potential for explaining the variance in the needle distribution. The normalized crowns are utilized in models for determining light extinction in the crown. A special technique for determining the amount of photosynthates available for growth in a particular tree is presented.
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The concept of tree class as indicated by dominant, codominant, intermediate and suppressed trees is analysed using empirical material representing 13 younger Scots pine (Pinus sylvestris L.) stands. The relative needle biomass, i.e. the needle biomass related to the maximum needle biomass in the stand, was closely related to the relative height of the tree and independent of the stand characteristics. Furthermore, the relative illumination of the crown system was related to the relative height of the trees as well as the relative photosynthetic capacity and tree-to-tree variation in growth. When calculated per needle biomass unit it appeared that height growth, radial growth, needle growth and other growth parameters were the highest in the suppressed trees. The suppressed trees thus appear to be more efficient in utilizing available resources than other tree classes. The ecologic significance of the results is discussed.
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The forestry working group of the committee for scientific and technical cooperation between Finland and the Soviet Union initiated cooperation work between the two countries in the field of forestry almost ten years ago. The Finnish organizations the Department of Peatland Forestry, the Finnish Forestry Research Institute, and the Institute of Peatland Forestry of the University of Helsinki participated in the activity. From the Soviet Union the participants have been the Ministry of Forestry, the Russian Federation of USSR, and the Forestry Research Institutes of Leningrad and Estonia.
This paper includes the papers presented in the joint symposium arranged at the Forest Field Station of University of Helsinki on 17.9.1979. The 9 Russian lectures and the 8 Finnish ones, are presented either in their entirety or slightly condensed variably in Finnish, English or Russian. The summary of the seminar is presented in English and in Russian.
In order to be recorded in the national list of untested seed orchards, set by law, a seed orchard must attain certain objectives. It is impossible to define universal requirements for all categories of seed orchards of all species. The present paper suggests minimum requirements for a clonal region seed orchards of Pinus sylvestris L in Finland. The clonal composition as well as factors influencing on the mating pattern have been given precise numerical threshold values. To be approved the seed orchard must fulfil all the requirements at the same time. The goal is to control the genetic superiority of the forest reproductive material obtained from registered untested seed orchards.
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Research into the forestry behaviour of private forest owners in Finland began 10 years ago. The private forest owners have been dichotomously classified into two groups, farmers and non-farmers. The farmer forest owner was considered to derive his main income (earnings) from agriculture. This classification is compared to the concepts in statistical publication Farm Economy 1976 (Maatilatalous). On the basis of this examination, it is recommended that researchers dealing with the behaviour of private forest owners should change their classification to agree with the concepts presented in the Farm Economy statistics. The recommended concept of farmer forest owner is understood as a forest owner who has taxable net incomes (state taxation) from farming. Other private forest owners are classified as non-farmers.
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The dying-off of more trees in an over-aged Norway spruce (Picea abies (L.) H. Karst.) stand caused by Ips-bark beetles was reduced by a pheromone preparation, ipslure. 20 preparations placed in trapping bolts captured more than 13,700 specimens of Ips typographus L. and Ips duplicatus Sahlb., which alone corresponded to a saving of five old trees in this valuable exhibition and seed collection stand. Attractance of ipslure to the following predators of bark beetles was also examined; Thanasimus formicarius, T. rufipes, Epuracea bickhardti, Rhizophagus ferrugineus, Pityophagus ferrugineus.
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This article is a book review on a Finnish book 'Dynaamiset mallit kasviekologiassa' by Holmberg. A., Mäkelä A and Sievänen R., concentrating on dynamic models in plant ecology.
This article is a book review on a Finnish book 'Luonnon olosuhteiden huomioonottaminen uusien asuntoalueiden suunnittelussa' by Kellomäki, Seppo and Lakka, Aura, concentrating on utilization of forests in urban planning.
Soft X-ray radiation (Grenz rays) has been used in the X-ray radiography of seeds. It is based on the principle that the different parts of the seed absorb X-rays to a slightly varying extent. Empty seeds and empty regions in the seeds appears as dark areas on the film. X-ray radiography without staining and X-ray contrast radiography were compared to study the stored seeds of Scots pine (Pinus sylvestris L.). The results were compared with the results of germination in a Jacobsen germinator according to ISTA norms.
Normal X-ray radiography gave too good estimates of germinative capacity of the seeds, and was shown to suit only when it is used to study fully ripe seeds which have recently been collected in an undamaged condition. The results of X-ray contrast radiography when barium chloride was used as the stain, however, followed closely the germination results.
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The aim of the present study was to establish whether hormone treatments would promote flowering in Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) H. Karst.) grafts under Finnish conditions. Also, an attempt was made to test the efficiency of hormones as well as the variation in response among different clones. Six Scots pine and six Norway spruce clones were selected in each seed orchard based on their flowering intensity, and treated with growth hormones (GA, NAA) of different dosages by spraying. Flowering was observed one year after the treatments.
None of the treated or untreated spruce grafts flowered. However, poor flowering in the natural stands indicated that the environmental conditions during the previous years did not favour flowering. On the other hand, a distinct increase in flowering in Scots pine was observed as a result of spraying with hormone solutions. Treatments with gibberellin had a distinct promoting effect both on male and female flowering in the Scots pine grafts, although the responses varied between the different hormones or clones. The relative effect was generally stronger in male flowering.
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In this paper the connection between seed weight and amount and duration of growth are studied at the progeny level within stands or climatically uniform areas, and at the provenance level within larger geographic areas. The material consists of materials of several experiments in the nursery of Maisala in Southern Finland in 1971–76. The origins of the plant material used in the different experiments ranged from progenies of individual Scots pine (Pinus sylvestris L.) or Norway spruce (Picea abies (L.) H. Karst.) trees to provenance selections covering almost the whole natural range of these species.
The effect of seed weight on plant height is strongest immediately after germination and subsequently decreases steadily, when the genetic growth properties of the plants themselves become effective. The effect is usually visible at least until the end of the 1st growing season. This relationship varies considerably depending on the material studied. The connections between the duration and the amount of height growth also proved to differ according to the nature of genetic variation. In wide selection of provenances, which show clear genetic differentiation in annual growth rhythm. The variation in the duration of growth accounts for most of the differences in total height growth. At the individual and family level or between provenances of a limited area, there seems to be no clear connection between the duration and the amount of growth. It seems that the duration of the annual growing period is a genetic property, which is not affected by seed weight.
The total height alone in 1-year old test material grown in a greenhouse had hardly any value in the forecasting of growth capacity. The growth differences were caused mainly by the variation in seed size and growth rate differences during the growing period.
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The paper discusses the theoretical basis of quantitative analysis of the effect of genotype and environment in forest trees. Perhaps the main problem in the understanding of the laws of intrapopulation variability of the species of woody forest plants is the study of the structure of their populations. It may be characterized by a number of parameters. The intrapopulation variability of quantitative characteristics appears as a result of environmental and genetic factors, but to determine the relative weight of these factors in a concrete case is not easy. The study of the structure of a population by its quantitative characteristics has a wider task: to establish the relevance of the hereditary differences of the individuals of a population. Also, the differences caused by diverse growth conditions and how they are reflected in the level of general phenotypic variability of the quantitative characteristics in a given population has to be identified. The author gives examples of assessment of heritability in forest trees.
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The paper discusses the variation of flowering and seed crop of Scots pine (Pinus sylvestris L.) stands based on literature published in Finland. According to the studies, the list of good seed years given by different authors do not completely match, and no essentially new about the periodicity of the seed crop or the causes of variation has been found. The difficulty in classification of the seed crops in different years in different stands and locations can be handled through the concept of capacity. It is suggested in the paper that to be able to compare the occurrence of good flowering and seed years of different stands and localities, a case exceeding 50% of the capacity is described as abundant, and a case exceeding 75% as very heavy.
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Establishment of seed orchards to produce genetically improved seed started in the USSR in the 1960’s. The aim is that within 10–15 years the total seed production will reach 50% of the seed used. The paper describes seed production in seed orchards of Scots pine (Pinus sylvestris L.) in the forest-steppe of the European part of the USSR. The orchards have been established either by grafting or by planting of seedlings originating from plus trees. The grafts begin flowering relatively early, however, only at the age of 8–10 years seed crops become relatively regular and abundant. The cone yield in young seed orchards have great variability, and the yield of cones varies between clones. Cone yield does not always correlate with a good seed yield. One of the reasons for high amount of empty seeds is the difference in the periods of flowering between the clones.
The seed crops can be improved by establishing optimal conditions for the growth of the trees. Also, when a seed orchard is founded, the peculiarities of the generative activities of the clones and their reactions to changes in the environmental conditions must be taken account by taking an individual and selective measure approach to improvement measures. The orchards can be established with clones for their genetic combining ability and their requirements for the stimulation of seed-bearing.
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Cutting propagation of forest trees has recently been done in Finland mainly by the Foundation for Forest Tree Breeding. The aim has been to develop methods which could be used in forest nurseries for large scale production of rooted cuttings. Methods are being developed for tree species which seem to offer possibilities for economically profitable vegetative propagation. The most important tree species has been Norway spruce (Picea abies (L.) RH. Karst.), and also larches (Larix sp.), lodgepole pine (Pinus contorta), birches (Betula sp.), alders (Alnus sp.) and hybrid aspen (Populus tremula x P. tremuloides) are propagated. The sensitive rooting phase takes place in plastic greenhouses which have ventilation on the roof top, mist irrigation equipment and separate heating systems for the air and the ground. Methods used for cutting propagation of Norway spruce, lodgepole pine, larch species and broadleaved trees are described.
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Planting of forest trees takes place in USSR on millions of hectares but without permanent forest seed bases having yet been established in every region of the country. Consequently, local seed does not suffice the need, and it is necessary to secure it from other geographical regions. To avoid negative consequences of seed transfer it is necessary to study geographic variation of the genetic characteristics of forest trees and construct scientifically based division into seed zones. Geographic transfer of seed can also be regarded as a breeding measure. A large research program is being carried out in the USSR on the subject. Most of the existing trials are provenience tests of Scots pine (Pinus sylvestris L.). Over 2,000 hectares of new provenience experiments is to be established in near future.
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The study concerned with variations in the density of the wood of different provenances in provenance test series of Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) RH. Karst.), established in 1931. Increment cores were collected from 10 sample trees from each sample block. The density of the pine wood was noticeably higher than that of spruce. The basic density was in average 450 kg/m3 for Scots pine, and the variation between different origins was 3–9%, while the average basic density of spruce was under 400 kg/m3 and the variation 3–10%. Statistically significant differences were found between the mean basic densities of different provenances in all sub-experiments for spruce, but only in one pine sub-experiment. However, these differences were not due to the altitude or latitude of the place of the origin. Volume growth seems to be the dominant component in the formation of dry matter yield.
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The productivity and several morphological features of Estonian Norway spruce (Picea abies L. Karst.) show significant geographical variation. This is no doubt because of differences in the climatic and soil conditions, which in spite of the small area of the country is quite large. In order to check the possible geographical variability of the gene pool, preliminary experiments were carried out in 1969, when seeds from 93 spruce stands originating from 14 forest enterprises were sowed in a nursery. After two years, the seedlings originating from south-eastern Estonia were the tallest. The seedlings from northern origins were smallest. However, it cannot be maintained that spruces from Southern Estonia are of better genotype than genotype from Northern Estonia since the genotypes are evaluated on the basis of ecological conditions under which the experiments are carried out. Another study suggests that an average shift of 7° to the east of the territory for spruces are suitable for cultivation in Estonia.
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Ecological investigations have shown that Norway spruce (Picea abies (L.) H. Karst.) reached Western Finland about 1,500–1,000 years B.C. and did not reach Åland islands before around the year 0. The species spread into Finland from the east and north-east, having survived the glaciation somewhere in the central parts of the Asian continent. Geographical variation has provided foresters with provenances of better growth and higher economic yield. In Finland, provenances, for instance, from Austria, Eastern Germany, Romania, Southern Poland and Slovakia have been planted in experiments, mostly in various parts of Southern Finland. According to the results of the experiments, it seems that for the more northern parts of Finland and Sweden the best material was to be obtained from north-east Europe.
The Scandinavian countries decided in 1975 to make a common assessment of all the provenance experiments with Norway spruce. The synthesis confirms the earlier view that provenances from the most north-eastern parts of Central Europe are of the greatest value for Finland.
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The development of the scientific basis for the production of high-quality seed led to the introduction of a large part of the research findings in forest genetics and forest tree breeding into practical forest seed production in the USSR. Since 1971, work has begun in forest enterprises on the establishment of a permanent seed supply for the main tree species – Pinus sylvestris, Picea ssp., Larix ssp. Quercus robur, Haloxylon ssp. and nut trees.
The basis for forest tree improvement is a gene pool which is built up using mass and individual selection of valuable forms in natural populations. In accordance with a long-term programme up to 1990, an inventory of 13.2 million ha of the best high-productive stands has been carried out for breeding purposes in the state forests. About 7,000 ha of plus stands have been selected, and a total of 9,453 ha of seed orchards and 141,253 ha of seed collection stands have been established. The first stage of the programme is planned to be complete in 1980, and in the second stage clonal high-quality seed orchards will be established.
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In the first part of the study the hindrance of the remaining trees when felling trees by machines working from the strip road in selective thinning was studied on the basis of the literature. In the second part there was geometrically studied the need of schematic thinning in some type stands when bundles are pre-skidded straight-lined to the strip road. In average only 0-1 trees per pre-skidding trail needs to be removed. It was concluded that trees removed from the pre-skidding trail do not significantly increase the need of schematic thinning. Remaining trees do not limit the length of machine booms if the pre-skidding trails are planned during the felling.
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As a part of the scientific and technical cooperation between Finland and the USSR a symposium and an excursion on forest genetics and seed production was organized in Finland in August 1978. The symposium paper presented at Punkaharju are published here in order to bring them available for a wider audience.
The 12 symposium reports deal with the following subjects: Practical application of forest genetic research (A.I. Novoselceva), geographical variability and provenance transfer (E.P. Prokazin, M. Hagman, I. Etverk), variation in wood density (P. Velling), variation of flowering and seed crops in seed orchards (Y.P. Efimov), and natural stands (V. Koski), vegetative propagation (J. Niiranen), seed size effects and early test problems (J. Mikola), quantitative analysis of genotypic and environmental effects (S.A. Petrov), hormonal induction of flowering (O. Luukkanen) and x-ray photography analysis of the ageing of seeds during storage (M. Ryynänen).
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Energy intake of ten lumberjacks in Eastern Finland was estimated by using 24-hour recall. In addition, serum cholesterol and triglycerides were analysed in different lipoprotein fractions. Average energy intake was according to present recommendations in Finland, although there was great individual variation. Serum triglycerides were in the normal range. Five lumberjacks’ total cholesterol concentration was somewhat increased. Average HDL concentration was clearly greater than in men of the same age.
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Radial growth of Scots pine (Pinus sylvestris L.) was investigated in seven camping areas located in Southern Finland. Radial growth reduction of 20–40% were found. The magnitude of this reduction was related to the amount of damage in the trees, and the age of the trees. A loss of humus, exposure of the roots and soil compaction were associated with the use of area but not related to the reduction in growth.
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