Articles containing the keyword 'MAI'

The condition of forest road pavements was studied in spring, one week after maintenance and in autumn. The effect of vibrating blade was slightly better than that of pulled drag. Large loose stones couldn’t be pressed into pavement with either of the implements. The use of the vibrating blade was three times as expensive as the use of the pulled drag, however, the blade is suitable for other purposes as well.

The PDF includes an abstract in Finnish.

• Rummukainen, E-mail: ar@mm.unknown

The paper presents aspects of town and forest architecture. A feature of the Finnish building tradition is that the forest is allowed to grow next to buildings. After the Second World War a new type of town was created in Finland, ”the forest town”. The most prominent feature of the history of Finnish architecture, from national romanticism to functionalism and up to the present day, is the modification of international ideals to a certain ”forest culture” style.

The paper is based on a lecture given in the seminar ‘The forest as a Finnish cultural entity’, held in Helsinki in 1986. The PDF includes a summary in English.

• Pallasmaa, E-mail: jp@mm.unknown

The Finnish forest was elevated into an appreciated artistic motif by Werner Holmberg with his picture ”The Finnish conifer forest” in 1858. The second significant period was during national romanticism in the 1980’s, when the decorative beauty of the winter forests was discovered. At the turn of the century, the forest obtained a central national symbolic significance, and many leading artists regarded increased cuttings as a rape of the forests. Since that period, individual artists have succeeded in bringing new features in the art history of our forests.

The paper is based on a lecture given in the seminar ‘The forest as a Finnish cultural entity’, held in Helsinki in 1986. The PDF includes a summary in English.

• Reitala, E-mail: ar@mm.unknown

The earliest manor parks, which are a special form of cultivated forests, were created at the end of the 18th century. The surrounding of the main buildings was divided into two parts, an aesthetic park and yard serving household and economic purposes. Early in the 19th century, large parks were created which represented dominant aesthetic ideals but, on the other hand, formed a ”wild” counterpart to the structured inner world of the main building. A good example is Ratula Manor and its park, which represent the diversity of the cultivated forest of the 19th century manors.

The paper is based on a lecture given in the seminar ‘The forest as a Finnish cultural entity’, held in Helsinki in 1986. The PDF includes a summary in English.

• Lönnqvist, E-mail: bl@mm.unknown

The main features of the Finnish landscape are a result of preglacial erosion processes and the structural lines of the bedrock. The microstructure of the landscape was created by the Ice Age and its melting processes. Upon this base, human activities have created a palimpsest of cultural landscapes. The article describes the effects of slash-and-burn cultivation, tar production, cattle ranging and some other forest uses to the forest landscape. 

The paper is based on a lecture given in the seminar ‘The forest as a Finnish cultural entity’, held in Helsinki in 1986. The PDF includes a summary in English.

• Linkola, E-mail: ml@mm.unknown

The article compares forest images in provincial and patriotic songs and in forest advertisements by banks and insurance companies. In songs, coniferous forests represent the primaeval nature and broadleaved forests represent culture. Coniferous forest is the real patriotic forest. Forest images in advertisements are twofold: both elevated patriotic forests and profane raw-material forests are found.

The paper is based on a lecture given in the seminar ‘The forest as a Finnish cultural entity’, held in Helsinki in 1986. The PDF includes a summary in English.

• Julkunen, E-mail: ej@mm.unknown
• Kuusamo, E-mail: ak@mm.unknown

This publication consists of 16 papers on importance of forests to Finns, mainly from the viewpoint of various social and humanistic sciences. The articles are based on lectures given to a seminar organized in Helsinki, December 18-19, 1986.

This paper includes preface and list of the speeches in English.

• Reunala, E-mail: –
• Virtanen, E-mail: –

The aim of this concise interview survey was to collect information about the servicing properties of forest tractors. Ten interviewees gave grades (in a scale from 4 to 10) concerning two servicing properties of various types of forest tractor. The rating covered the general safety during servicing (structural serviceability) and work postures during the work. Four types of forest tractor widely-used in Finland were chosen. The forwarders were of different size and structure.

According to the rating, the lightest forwarder was clearly superior to the other types. This machine was also the smallest in size and the most modern. Differences between the other three forwarders were not quite so clear. The variation between the machines as regards both so-called easy and troublesome tasks was considerable. Lubrication of the articulated shafts and supporting bearings was, however, very troublesome regardless the machine type. The heaviest tractor was considered the most difficult to service.

The PDF includes a summary in English.

• Rieppo, E-mail: kr@mm.unknown
• Väyrynen, E-mail: sv@mm.unknown

Using literature and a simulator experiment, an ordinary processor and a grapple loader processor were compared in conditions corresponding to thinning later than the first commercial thinning. Visual bucking only was employed in the simulator experiment. The strip road spacing was 30 m and there was no preliminary skidding of the trees. The simulator experiment confirmed the view reached in the literature that work productivity of the grappler loader processor is 20–40 % greater than that of an ordinary processor provided that the stem size is under 0.2–0.4 m3.

The PDF includes a summary in English.

• Harstela, E-mail: ph@mm.unknown
• Maukkonen, E-mail: am@mm.unknown

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.

The PDF includes a summary in English.

• Karhu, E-mail: ik@mm.unknown
• Kellomäki, E-mail: sk@mm.unknown

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.

The PDF includes a summary in English.

• Harstela, E-mail: ph@mm.unknown

The article describes the two approaches which are evident in planning and management of nature and landscape. One is based on traditional architectural thinking, emphasizing the significance of subjective intuition and practical creative work. The other has evolved from the study of the economic utilization of natural resources, emphasizing the significance of rational thinking and scientific analysis.

This paper was presented in the ‘Man and the Biosphere’ programme project 2 seminar held on August 24–25 1978 in Hyytiälä research station of University of Helsinki.

The PDF includes a summary in English.

• Simons, E-mail: ts@mm.unknown

The article describes the results of the studies made in 24 Finnish housing areas. They show that the building density is not as important as the way of building and the site planning, in the view of preserving natural vegetation in the site. Building on slopes was difficult with modern building techniques because of the extensive earthwork required. 

This paper was presented in the ‘Man and the Biosphere’ programme Project 2 seminar held on August 24–25 1978 in Hyytiälä research station of University of Helsinki. 

The PDF includes a summary in English. 

• Rosengren, E-mail: cr@mm.unknown

The study deals with economic significance of forest landscape planning models used in regional planning in Finland. The »judge»-method is used among professional foresters working on private forestry boards in Southern Finland to define their view of what would be moderate level of costs of landscape management for private forest owners. A sample of 154 forest professionals working in district forestry boards in Southern Finland was sent a sociological questionnaire.

It was possible to form three hierarchical moderation classes by statistical grouping of judgement distributions. Prolongations in rotation ages and restrictions concerning ditching of forested bogs, forest read building and clear-cutting were considered the most immoderate models. Rather or wholly insignificant were evaluated such management models, which mean restrictions in »old fashioned» methods or which are already used in practice.

The PDF includes a summary in English.

• Lovén, E-mail: ll@mm.unknown

This paper deals with the problem of optimal multiple use of forests. The concept of attractive visual environment is analysed following the framework of conditional reflexes and conditionalization of needs. Uniformity of landscape preferences among a group of persons, forest professionals working in district forestry boards in Southern Finland, who have similar education and working environment is studied in empirical part of this paper. The sample of 154 persons were sent a sociological questionnaire.

The preference distribution of forest officers and forest technicians were found very similar. Only poor condition for wood production as a landscape feature was considered clearly negative. The answers show the demand for rational and active working environment as a factor directing the landscape preferences.

The PDF includes a summary in English.

• Lovén, E-mail: ll@mm.unknown

The purpose of forestry has hitherto been seen mainly as economic conservation, i.e. the use and management of timber resources on a sustainable yield basis. Along with the rising standard of living, however, amenity values of the environment will become more appreciated, which means that forestry and forest industries will be concerned with conservation of immaterial resources of nature as well. Since inland lakes cover some 10% of the surface area of Finland, and forests occupy more than 70% of the land area, forests and lakes are essential constituents of the Finnish environment during both work and leisure.

The main task of the pulp and paper industry in conservation is the control of water pollution. Today some 10% of Finnish lakes are polluted. Pulp and paper industries contribute 75% of the total waste water load of the Finnish lakes. Increasing water pollution can be prevented by improved processing technology, waste water treatment, and economic use of industrial wastes. Thus, the waste water load of the lakes has not increased in the last 10 years, despite doubling of pulp and paper production. According to the prognoses, by the year 2000 the waste water load from pulp and paper industries will be reduced to one half or one fourth of the present level although the capacity will still be increasing.

In forest management more emphasis should be paid on the aesthetic and recreational values of forests. Along with increasing leisure the need for recreational areas is growing. Scenic and recreational aspects must be considered in the management of industrial forests, too. With wise management, high timber yield is compatible with the maintenance of an enjoyable environment. Good silviculture takes account of timber production, wildlife management and landscape architecture simultaneously. National forestry development programs must be based on the principle of the multiple use of forests.

The PDF includes a summary in English.

• Mikola, E-mail: pm@mm.unknown

Nordiska skogsarbetsstudiernas råd (NSR, Council for Inter-Scandinavian Research in Forest Work Science) is the most developed organization in this field. It has only research institute members. The council started in 1953 and has since then had meetings and working groups. Among the latter, an Inter-Scandinavian and British wood nomenclature was created. In 1969 the organization will start a number of joint investigations, two of them in Finland, concerning utilization of waste wood and transport difficulties in forest terrain. Sweden will study branching, Norway relations between men and machines and Denmark broadleaved tree cutting and hauling.

Economists have since 1958 had an Inter-Scandinavian Seminar for Forest Economists (Nordiskt skogsekonomiskt Seminar, NSS), which has only personal members. Also, Inter-Scandinavian forest congresses have been held every fourth year since 1923, in which also research results have been presented.

The PDF includes a summary in English.

• Heikinheimo, E-mail: lh@mm.unknown

The aim of this present study was to elucidate the quality of seed of foreign tree species grown in Finland, and the factors which have affected the quality of the seed yields. Due to the smallness of the material, however, no far-fetching conclusions can be drawn. The bulk of the seeds were collected in the fall of 1964. The samples of seeds were X-rayed and their classification to empty seeds and full seeds of four quality classes was done on the basis of the anatomical structures. The species studied (a total of 34 species) belonged to the following genera: Abies, Chamaecyparis, Larix, Picea, Pinus, Pseudotsuga, Thuja and Tsuga.

The percentage of empty seeds was throughout quite high. The reasons for the generation of empty seeds probably originate from the special nature of the stands from which the seeds were collected. As a rule, the stands were young and small in area, which may have caused weak pollination and self-pollination leading to embryo mortality. Also, insect damages were observed.

Seeds with albumen still discernible, although the embryo had died, occurred to some extent. In some Larix species, even the bulk of the seeds recorded as full belonged in this group.

The ripening of seeds with embryos was quite successful in spite of the fact that the temperature sum of the year of ripening was slightly below the average in Finland. For instance, all Abies species ripened almost completely.

According to the results, it can be expected that the tree species examined in this study are able to produce rich yields of good-quality seed in Finland, provided that the ovules are well pollinated and self-pollination does not take place to a large extent.

The PDF includes a summary in English.

• Tiililä, E-mail: pt@mm.unknown

Foreign tree species have been planted in Finland since 1900s, the most famous being Larix sibirica plantations in Raivola in Karelia, which now belongs to Soviet Union. One of the largest larch plantations of Finland today is situated in Tuomarniemi, in Central Finland. Ten larch stands were established in Tuomarniemi between 1912 and 1937 mainly by planting. The stand established in 1937 was sown. The trees represent five larch species: Larix sibirica Ledeb. (5 stands), Larix gmelinii var. kurilensis (2 stands, current name probably Larix gmelinii var. gmelinii), Larix americana Michx. (1 stand, now Larix laricina), Larix decidua Mill. (1 stand) and Larix occidentalis Nutt. (1 stand). The total area of the larch stands is 82.5 ha. This paper reports the studies made in the plantations in 1958.

In Tuomarniemi larch grows well in many types of soil from Vaccinium type sites to fresh mineral soil sites. The age of the stands varies from 19 to 48, height from 12 to 24 metres and annual growth from 5 to 12 m³/ha. Larix sibirca has the best stem form of the species, followed by L. gmelinii var. kuriliensis. Easiest to split is the straight-grained L. gmelinii var. kuriliensis. L. sibirica is almost as easy to process. The wood of L. decidua, on the other hand, is often spiral-grained and tough. The trees are seldom infected with decay fungi.

The PDF includes a summary in German.

• Kolehmainen, E-mail: vk@mm.unknown

This paper concentrates on analysing advertising of building materials used in residential, agricultural and factory building, power station construction, warehouse building and the joinery industry in Great Britain, concentrating on advertising to consumers, including architects, engineers, building entrepreneurs, farmers and do-it-yourself practitioners. The material is based on questionnaires answered by 8 professionals of the field, and assessment of two leading English paper in the field of construction in January 1 – June 30, 1959.

It was concluded that forest products were clearly less advertised than other building materials. The unweight average degree of advertising of all forest products was. 1.7, while the score was 2.6 for other materials. Of the different forest products stand out advertising of plywood and sawn good. The most extensively advertised materials were metals, concrete and cement, and some covering materials. Forest products accounted only ¼ of the advertising space in the publications.

The most important media used in advertising building materials were trade journals, calendars and yearbooks, courses and lectures, exhibitions and fares and direct advertising. The most important audience of advertising were architects, followed by the entrepreneurs. It is suggested that the advertising of Finnish products in Great Britain might be best organized by placing it in the hands of two organizations: the sales organisation and a separate body for advertising. The producers would manage the advertising of individual brands to sales level, while the other levels (agents, importers, merchants) would manage the joint advertising of the forest products to the lower sales levels and consumers. A Finnish market research and information offices might be established in Great Britain.

The PDF includes a summary in Finnish.

• Ervasti, E-mail: se@mm.unknown

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 discusses forest management practices of drained peatlands and the allocation of responsibilities in draining of peatlands between district forest officers and forest officers responsible of drainage work. Problems has occured in those cases, when the process of draining had lasted so long that at the time of final assessment of the project the first ditches have already needed maintenance.

• Lukkala, E-mail: ol@mm.unknown

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 discusses legal aspects of cases when property has been used without property rights. Examples related to forestry, hunting, fishing and reindeer husbandry are presented.

• Komsi, E-mail: tk@mm.unknown

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 nature turism and recreation in Finland, how timber harvesting and nature conservation affect tourism and ways to adjust fellings to tourism.

• Heikinheimo, E-mail: oh@mm.unknown

The issue 39 of Silva Fennica includes presentations held in professional development courses in 1935 that were arranged for foresters working in public administration. The presentations focus on practical issues in forest management and administration, especially in regional level.

This presentation describes building and renovation of wooden buildings, that were owned by the forest organizations.

• Lehtinen, E-mail: il@mm.unknown

Silva Fennica Issue 39 includes presentations held in professional development courses in 1935 that were arranged for foresters working in public administration. The presentations focus on practical issues in forest management and administration, especially in regional level.

This presentation describes the use and maintenance of village roads.

• Simola, E-mail: es@mm.unknown

Silva Fennica Issue 39 includes presentations held in professional development courses in 1935 that were arranged for foresters working in public administration. The presentations focus on practical issues in forest management and administration, especially in regional level.

This presentation gives guidlines in building and maintaining roads in forest administration.

• Simola, E-mail: es@mm.unknown

Trees and shrubs of foreign origin have been grown in Finland at least from the 1700th century. At the State Horticultural Institute in the neighbourhood of the town Turku in southwestern coast of the country, a number of ornamental trees and shrubs have been planted since 1927. During the first decade, weather conditions were quite favourable, but the winters in 1939–1940 were so severe, that only the hardiest plants survived.

It would be important to study hardiness and suitability of the various woody plants cultivated in the different parts of the country. This paper includes notes of the survival of the tree species and shrubs so far planted at the Institute.

The PDF includes a summary in English.

• Meurman, E-mail: om@mm.unknown

The article is a report of the exotic tree and shrub species found in major parks and gardens in the city of Tampere, in Southern Finland, and the surrounding areas, including fruit trees and berry bushes. The survey of species was conducted in 1934-1935. There was a total of 221 tree and shrub species in the 245 parks and gardens of the city. Exotic species was found 193, of which 37 was introduced only recently. The frequency of 199 species in Tampere area and the condition of each species is listed. Most common are the native species of the genus Picea, Pinus, Betula, Acer, Prunus and Sorbus. Of the exotic species only Malus pumila (Mill.) is commonly cultivated. Relatively common are Ulmus montana (With.), Tilia cordata (Mill.) and Fraxinus excelsior (L.).

The PDF includes a summary in German.

• Saarnijoki, E-mail: ss@mm.unknown

The development roots of Norway spruce (Picea abies (L.) H. Karst.) seedlings was studied in sample seedlings grown in different kinds of sites. In the early stage, the seedling roots grow primarily length. The main root is usually long. If the growth of the root is hindered, the tip of the root dies, and the root system growing from the original root collar remains relatively small; in these cases, the secondary root system becomes more important. In unfavourable conditions the root branches can early on replace the main root. The main root of a germling seems to be less able to seek for free growing space than the main and side roots of older seedlings. When the growth of the root is blocked by some kind of obstacle, it does not often hinder the growth of the seedling. The type of soil influences strongly how the root system grows. In good soil and in humus the root system is regular and richly branched, while in clay and coarse sand the root system was small. Spahgnum moss was good substrate for seedlings, Dicranum undulatum moss little less good, while the seedlings grew poorly on Pleurozium Schreberi.

The PDF includes a summary in German.

• Hertz, E-mail: mh@mm.unknown

The growth of 35 exotic tree species in garden established in 1912 is discussed in the article. The site is located in Kulosaari, Helsinki in the Southern coast of Finland. The species represented the Chamaecyparis, Abies, Tsuga, Picea, Larix, Pinus, Betula, Fagus, Quercus, Juglans, Populus, Salix, Tilia, Acer, Prunus, Crataegus and Amelanchier families. All the tree species from northern continental climate and most of the species of temperate regions grew well or moderately well. Species form northern oceanic climate succeeded moderately well. The species from southern continental or oceanic climate did not endure the climate in Kulosaari. Definite conclusions were not possible to make, because the precise origin of the seedlings was not known, and there was usually only one tree from each species.

The PDF includes a summary in German.

• Tikka, E-mail: pt@mm.unknown

• Valle, E-mail: kv@mm.unknown

The article contains a literature review about the spatial order of plants and a description of the small-scale experiments with corn. The literature is primarily of German origin. The question of the spatial conditions of trees in forest is important for practice of silviculture. The first part of the article illustrates based on the literature the importance of roots and root concurrence for the development of plants or forest stands. The second and third part deepens the methodological knowledge on root research. Fourth part is the field experiments with corn. There are no clear relation to be found between yield and the number of plants.  

• Aaltonen, E-mail: va@mm.unknown

The article describes experiences in exotic tree and shrub species in Mustila arboretum in 1901-1921, situated in Southern Finland. Mustila is the first arboretum of the country, established in 1901. The tree species have mostly been planted as small stands or groups of trees. The objective has been to find species that suit the Finnish climate. The article describes experiences of cultivation trials of coniferous tree species from the genus of Taxus, Tsuga, Pseudotsuga, Abies, Picea, Larix, Pinus, Thyopsis, Thuya, Chamaecyparis and Juniperus, in total 100 different species. The climate of Finland ranges from maritime to semi-maritime and semi-continental, becoming more continental towards the eastern parts of the country. According to the experiments, in Mustila area most promising are the Western American species from regions that are suitable distance from the Pacific Ocean. The exact origin of the seeds in the America is important for the survival of the species in Finland.

The PDF includes a summary in English.

• Tigerstedt, E-mail: at@mm.unknown

The article includes a dendrological review on the effect of climate to the success of cultivation of exotic tree species, based on literature and analysis of the existing Finnish field tests. The cultivation of an exotic tree species succeeds only if the seed has been procured from an area, which climate is similar to the place of cultivation. Climate is even more important than site quality.

Finnish climate is boreal and continental, and thus tree species of similar climate suit here best. In favorable site conditions it is possible to grow also species from boreal marine, and temperate climates. Finnish summers are not warm enough for species from temperate continental climate to get prepared for the winter, and the shoots can get frost damages. This may be compensated with a warm and sheltered site. If the species tolerates shading, it can be planted under sheltering trees. For species from maritime boreal climate, the Finnish summer tends to be too short, and the winters too cold. A suitable site is rich, warm and sheltered, and has preferably a protective sparse tree cover. Species from southern maritime climate cannot be grown in Finland. The provenance of the seeds is also very important. An important source of seeds are the successful plantations in Finland.

The PDF includes a summary in German.

• Ilvessalo, E-mail: li@mm.unknown

Two approaches were applied in measuring the scenic value of forest landscapes. In the field, the scenic value of forest lands representing clear cut areas, as well as young closed stands and mature stands with varying tree species composition, were assessed. In the laboratory, the scenic value of the same stands was measured with the help of photographs of the same stand. The same persons representing forest students (36 persons) and city dwellers (25 persons) made the evaluation.

Stands of moderate density containing individual tall trees and a coniferous undergrowth had the greatest scenic value, independently of the tree species composition. However, birch was preferred to Scots pine and Norway spruce. Measurements made in the field by means of interviews, and in the laboratory based on photographs, gave very similar results. Photographs seem to represent a reliable tool for estimating the scenic value of forest landscapes.

The PDF includes a summary in English.

• Savolainen, E-mail: rs@mm.unknown
• Kellomäki, E-mail: sk@mm.unknown

The aim of the study was to search for measurement methods of muscle fatigue in forest work. Lactic acid concentration of capillary blood was measured from test persons after submaximal and maximal strain tests in laboratory and during forest work. At rest the lactic acid content was affected mainly by the body dimensions and blood pressure. In a maximal strain test it was affected mainly by the age. In submaximal forest work lactic acid content concentrated below the attitude factor indicating working pace and below the body dimensions so that bigger persons had a higher lactic acid concentration than smaller persons.

The PDF includes a summary in English.

• Wuolijoki, E-mail: ew@mm.unknown

The rate of vegetative spreading in oak fern (Carpogymnia dryopteris) and may-lily (Maianthemum bifolium) was studied by comparing the size of stands formed by individual plants of these species with those of other species growing on the same sites as well as with the time that had elapsed since the last fire on the sites and the age of the tree stand. The average maximum rates of spreading showed to be of similar magnitude in both species, being 12.6 cm/year in oak fern and 12.3 cm/year in may-lily; these values correspond to a radial growth of 6.3 and 6.1 cm year respectively. The maximum radial growth recorded was about 7 cm/year in both species.

The PDF includes a summary in Finnish.

• Oinonen, E-mail: eo@mm.unknown

We used a process-based hydrological model SUSI to improve guidelines for ditch network maintenance (DNM) operations on drained peatland forests. SUSI takes daily weather data, ditch depth, strip width, peat properties, and forest stand characteristics as input and calculates daily water table depth (WTD) at different distances from ditch. The study focuses on Scots pine (Pinus sylvestris L.) dominated stands which are the most common subjects of DNM. Based on a literature survey, and consideration of the tradeoffs between forest growth and detrimental environmental impacts, long term median July–August WTD of 0.35 m was chosen as a target WTD. The results showed that ditch depths required to reach such WTD depends strongly on climatic locations, stand volume, ditch spacing, and peat thickness and type. In typical ditch cleaning areas in Finland with parallel ditches placed about 40 m apart and tree stand volumes exceeding 45 m³ ha^–1, 0.3–0.8 m deep ditches were generally sufficient to lower WTD to the targeted depth of 0.35 m. These are significantly shallower ditch depths than generally recommended in operational forestry. The main collector ditch should be naturally somewhat deeper to permit water outflow. Our study brings a firmer basis on environmentally sound forestry on drained peatlands.

• Hökkä, Natural Resources Institute Finland (Luke), Natural resources, Latokartanonkaari 9, P.O. Box 2, FI-00791 Helsinki, Finland E-mail: hannu.hokka@luke.fi
• Laurén, University of Eastern Finland, Faculty of Science and Forestry, School of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland E-mail: ari.lauren@uef.fi
• Stenberg, Natural Resources Institute Finland (Luke), Natural resources, Latokartanonkaari 9, P.O. Box 2, FI-00791 Helsinki, Finland E-mail: leena.stenberg@luke.fi
• Launiainen, Natural Resources Institute Finland (Luke), Bioeconomy and environment, Latokartanonkaari 9, P.O. Box 2, FI-00791 Helsinki, Finland E-mail: samuli.launiainen@luke.fi
• Leppä, Natural Resources Institute Finland (Luke), Bioeconomy and environment, Latokartanonkaari 9, P.O. Box 2, FI-00791 Helsinki, Finland E-mail: kersti.leppa@luke.fi
• Nieminen, Natural Resources Institute Finland (Luke), Natural resources, Latokartanonkaari 9, P.O. Box 2, FI-00791 Helsinki, Finland E-mail: mika.nieminen@luke.fi

• Fernandez-Lacruz, Department of Forest Biomaterials and Technology, Swedish University of Agricultural Sciences, SE-901 83 Umeå, Sweden E-mail: raul.fernandez@slu.se
• Di Fulvio, Department of Forest Biomaterials and Technology, Swedish University of Agricultural Sciences, SE-901 83 Umeå, Sweden E-mail: fulvio.di.fulvio@slu.se
• Bergström, Department of Forest Biomaterials and Technology, Swedish University of Agricultural Sciences, SE-901 83 Umeå, Sweden E-mail: dan.bergstrom@slu.se

• Eriksson, SLU, Dept of Bioenergy, P.O. Box 7061, SE-750 07 Uppsala, Sweden E-mail: ee@nn.se
• Johansson, SLU, Dept of Bioenergy, P.O. Box 7061, SE-750 07 Uppsala, Sweden E-mail: tj@nn.se

• Matero, University of Joensuu, Faculty of Forestry, P.O. Box 111, FI-80101 Joensuu, Finland E-mail: jukka.matero@joensuu.fi