Articles containing the keyword 'edge'

Distribution and occurrence of bark beetles and other forest insects in relation to environmental variation were analysed by multivariate methods. Eight different forest edges were studied using 10 x 10 m sample plots that formed 200 m linear transects perpendicular to the forest edge. Forest edge affected the distribution of insect species only in the edges between mature, non-managed spruce stands and clear cuts or young seedling stands, but not in the pine stands. The occurrence of the selected forest insects mainly depended on variables associated with the amount and quality of suitable woody material. The most significant environmental variables were forest site type, crown canopy coverage, tree species, number of stumps, number of dead spruce trunks and amount of logging waste at site. Quantitative classification of species and sample plots showed that some specialized species (Xylechinus pilosus, Cryphalus saltuarius, Polygraphus poligraphus and P. subopacus) adapted to mature spruce forests, tended to withdraw from the forest edge to interior stand sites. By contrast many generalized species (Pityogenes chalcographus, P. quadridens, Pissodes spp., Hylurgops palliatus, Tomicus piniperda, Dryocoetes spp. and Trypodendron lineatum) benefitted from cuttings and spread over stand borders into mature forest.

• Peltonen, E-mail: mp@mm.unknown
• Heliövaara, E-mail: kh@mm.unknown
• Väisänen, E-mail: rv@mm.unknown

Decision making in the forest protection involves diagnosing the pest, making predictions of the effects of the pest on forest, knowing the possible control tactics, and cost/benefit integration. To cope with all that, a generalist forest manager needs a tool like an expert system to support decisions.

This paper presents an expert system that approaches the goals of integrated pest management. With the systm, the user can make diagnosis and predictions of 12 North European bark beetles. Written in Common LISP and Flavors, the expert system has a combined frame- and rule-based knowledge representation. Frames are used to represent the hierarchy of insect taxonomy in diagnosis. Prediction is made with qualitative reasoning with rules. The interface engine applies both forward and backward chaining. The system has a graphical user interface that supports exploring the sensitivity of advice on input.

It is concluded that expert systems and artificial intelligence have high applicability everywhere in forestry where complicated decisions have to be made. Especially, an integrated pest management system in forestry is largely equivalent to a computerized decision-making aid.

The PDF includes an abstract in Finnish.

• Saarenmaa, E-mail: hs@mm.unknown

The abundance of main invertebrate groups was studied in clear-fellings, forests and in edges between them in Northern Finland in June-August 1983. Five trapping transects were used. Each transect had 48 pitfall traps and 16 window traps on the ground and 4-6 window traps in bushes or trees.

Invertebrate groups Homoptera, Diptera, Formicidae, Coleoptera and Gastropoda were more abundant in forest than in clear-cuts according to the pitfall data. In window traps the catches of all the main groups were larger in the forest side. Six out of the eight most important groups preferred the edge in pitfall data. Formicidae, other Hymenoptera, Arachnida and Gastropoda were more numerous in the edges than in the interior habitats in both sides of the edge. In window trap material no consistent edge preference was found in clear-fellings, but in the forest side it was evident. Coleoptera and Arachnida preferred the edge on both sides of it.

The variations in the catches of the invertebrate groups were studied by regression analyses. Independent variables used were the distance to the edge, the coverage of mosses, litter, mineral soil, grasses and sedges, herbs and the density of saplings. The percentage of variance explained in multiple regression analyses were highest for the group of other Hymenoptera and Arachnida and lowest for Coleoptera and Homoptera. As regards the explanation power of the independent variables the distance to the edge and the density of saplings clearly exceeded the others.

The results support the assumption that the breeding bird densities at forest edges, which is often high, may depend on high prey density there.

The PDF includes a summary in Finnish.

• Helle, E-mail: ph@mm.unknown
• Muona, E-mail: jm@mm.unknown

The paper deals with the nutrient status of surface peat layer from virgin sedge-pine swamps and its relationship to peatland types. When the nutrients are expressed in mg/100 g peat, only easily extractable Ca and Mg correspond to the productivity status of the peatland type. N, P, and K levels in the herb rich sedge-pine swamp are generally lower than in the small sedge-pine swamps, which are the least productive ones. The differences between the site types in all the five nutrients become much clearer when the results are expressed in kg/ha. P, K, and Ca are significantly different between the site types, and correspond to the productivity of the site type. For N and Mg the same tendency can be seen. The organically bound nutrients N, and to a lesser extent, P appear to comply with the hypothesis of an increase in nutrient availability in Southern Finland.

The PDF includes a summary in Finnish.

• Starr, E-mail: ms@mm.unknown
• Westman, E-mail: cw@mm.unknown

The aim of the present study was to describe the diffusion of the professional insight in forestry taking place among forest owners and as factors attached thereto. The material is based on interviews of 289 forest owners in municipalities of Jämsä and Karstula in Central Finland in 1966. The forest owners were a random sample of all males in the municipalities, who were in the possession of at least 2 ha of cultivated land and 10 ha of forest.

Mass media (papers, radio and television) was an important source of information for the forest owners. Forest educational events are specially planned to spread information on forestry to forest owners, but 40% told that they had never participated any such event. Only 8% had got professional forest education. Knowledge concerning forests and forest management may also be inherited from the forest owner’s parents, or in discussions with professional forest officers or neighbours. About 73% of the forest owners had been in touch with professional foresters at least once during the last three years.

A third of the forest owners regarded professional insight their most important source of information on forestry, a little smaller group considered instruction in forestry questions the most important source. The third largest group had achieved their knowledge on forestry on own experience and inherited knowledge. Forest owners favouring mass media, own experience and inherited knowledge were often owners of a small forest holding.

The PDF includes a summary in English.

• Järveläinen, E-mail: vj@mm.unknown
• Vadén, E-mail: tv@mm.unknown

Fertility of surface peat from sedge pine mires was studied by measuring several edaphic growth factors: bulk density, volume weight of organic matter, ash content, acidity, electric conductivity, effective cation exchange capacity, degree of base saturation, and total contents of N, P, K, Ca and Mg. The 168 temporal sample plots were situated on virgin sedge mires in different parts of Finland, and the 30 permanent sample plots on two uniform sedge mires.

The results showed that peat bulk density and volume weight of organic matter tend to increase with increasing site quality. Ash content increased gradually in the site series from small sedge mire to the herb-rich sedge mire. The relationship between the total content of macronutrients in peat and the site quality is clear. The importance of bulk density in evaluating the site quality is further emphasized when taking into account its significant correlation to contents of N and P. The soil variables follow the accepted quality gradient of the site series. Consequently, the plant sociologically based site classification seems to reflect satisfactorily the average soil properties. However, the within site variation was significant.

• Westman, E-mail: cw@mm.unknown

It is commonly accepted that the period of early-spring xylem sap exudation marks a stage during which a positive pressure builds inside the tree trunks. This state changes when leaves appear, initiating water transport within the trunk. It is unknown, however, how the wood anatomical structure and its mechanical resistance influences the sap. We present the results of research on the relationship between exudation of sap from Betula pendula Roth trees from the interior of a forest stand and from its edge, and the anatomical structure of the trunk wood and its bending strength. During the period between March 21 and April 18, we performed five sets of measurements of sap exudation from trees at the edge of the stand and from the forest interior. The resulting radial wood samples were tested for bending strength using a fractometer. We tested the sap for electrolytic conductivity and sugars content. For the anatomical analysis of the wood, we determined the number of vessels per 1 mm², average vessel lumen area and potential conductivity index. We found that the trees along the edge of the stand exude more sap, but it is less concentrated than the sap from the trees from the interior. Bending strength perpendicular to wood fibres is higher in the trees from the stand edge and in the western side of the trunk, where the number of vessels per 1 mm² and conductivity index are smaller. Seemingly, this is the result of western winds, which are dominant in Poland.

• Zajączkowska, Department of Forest Botany, Faculty of Forestry, Warsaw University of Life Sciences, 159 Nowoursynowska St., 02-776 Warsaw, Poland E-mail: urszula.zajaczkowska@wl.sggw.pl
• Kaczmarczyk, Department of Forest Botany, Faculty of Forestry, Warsaw University of Life Sciences, 159 Nowoursynowska St., 02-776 Warsaw, Poland E-mail: karina.kaczmarczyk@wl.sggw.pl
• Liana, Department of Forest Botany, Faculty of Forestry, Warsaw University of Life Sciences, 159 Nowoursynowska St., 02-776 Warsaw, Poland E-mail: janusz.liana@wl.sggw.pl

• Franklin, Department of Renewable Resources, University of Alberta, 751 General Services Building, Edmonton, Alberta, T6G 2H1, Canada E-mail: cfrankli@ualberta.ca
• Harper, School for Resource and Environmental Studies, Dalhousie University, Suite 5010, 6100 University Ave., Halifax, Nova Scotia, B3H 3J5, Canada E-mail: Karen.Harper@dal.ca
• Murphy, Department of Environmental Science, Saint Mary’s University, 923 Robie St., Halifax, Nova Scotia, B3H 3C3, Canada E-mail: liamkmurphy@gmail.com

• Hamunen, Natural Resources Institute Finland (Luke), New Business Opportunities, P.O. Box 68, FI-80101 Joensuu, Finland E-mail: katri.hamunen@luke.fi
• Virkkula, Oulu University of Applied Sciences, Kotkantie 1, FI-90250 Oulu, Finland E-mail: outi.virkkula@oamk.fi
• Hujala, Natural Resources Institute Finland (Luke), New Business Opportunities, P.O. Box 18, FI-01301 Vantaa, Finland http://orcid.org/0000-0002-7905-7602 E-mail: teppo.hujala@luke.fi
• Hiedanpää, Natural Resources Institute Finland (Luke), Economy and Society, Itäinen Pitkäkatu 3, FI-20520 Turku, Finland E-mail: juha.hiedanpaa@luke.fi
• Kurttila, Natural Resources Institute Finland (Luke), New Business Opportunities, P.O. Box 68, FI-80101 Joensuu, Finland E-mail: mikko.kurttila@luke.fi

• Nilsson, Swedish University of Agricultural Sciences, Department of Forest Resource Management, SE-901 83 Umeå, Sweden E-mail: malin.nilsson@slu.se
• Staal Westerlund, Swedish University of Agricultural Sciences, Department of Forest Resource Management, SE-901 83 Umeå, Sweden E-mail: dianne.wasterlund@slu.se
• Wahlberg, Swedish University of Agricultural Sciences, Department of Forest Resource Management, SE-901 83 Umeå, Sweden E-mail: ow@nn.se
• Eriksson, Swedish University of Agricultural Sciences, Department of Forest Resource Management, SE-901 83 Umeå, Sweden E-mail: ljusk.ola.eriksson@slu.se

• Schiessl, Department of Genetics, Research and Training Centre for Forests, Natural Hazards and Landscape, Hauptstrasse 7, A-1140 Vienna, Austria E-mail: es@nn.at
• Grabner, Department of Material Sciences and Process Engineering, Institute of Wood Science and Technology, University of Natural Resources and Applied Life Sciences, Peter-Jordan-Strasse 82, A-1190 Vienna, Austria E-mail: mg@nn.at
• Golesch, Department of Genetics, Research and Training Centre for Forests, Natural Hazards and Landscape, Hauptstrasse 7, A-1140 Vienna, Austria E-mail: gg@nn.at
• Geburek, Department of Genetics, Research and Training Centre for Forests, Natural Hazards and Landscape, Hauptstrasse 7, A-1140 Vienna, Austria E-mail: tg@nn.at
• Schueler, Department of Genetics, Research and Training Centre for Forests, Natural Hazards and Landscape, Hauptstrasse 7, A-1140 Vienna, Austria E-mail: silvio.schueler@bfw.gv.at

• Lindroos, Swedish University of Agricultural Sciences, Department of Forest Resource Management, SE-901 83 Umeå, Sweden E-mail: ola.lindroos@srh.slu.se

• Siipilehto, Finnish Forest Research Institute, P.O. Box 18, FI-01301 Vantaa, Finland E-mail: jouni.siipilehto@metla.fi

• Burton, Symbios Research and Restoration, P.O. Box 3398, 3868 13th Avenue, Smithers, British Columbia, Canada V0J 2N0 E-mail: symbios@bulkley.net

• Leskinen, Finnish Forest Research Institute, Kannus Research Station, P.O. Box 44, FIN-69101 Kannus, Finland E-mail: pekka.leskinen@metla.fi
• Kangas, Finnish Forest Research Institute, Kannus Research Station, P.O. Box 44, FIN-69101 Kannus, Finland E-mail: jk@nn.fi

• Daume, The University of Edinburgh, Institute for Representation and Reasoning, Division of Informatics, 80 South Bridge, Edinburgh EH1 1HN, United Kingdom E-mail: stefand@dai.ed.ac.uk
• Robertson, The University of Edinburgh, Institute for Representation and Reasoning, Division of Informatics, 80 South Bridge, Edinburgh EH1 1HN, United Kingdom E-mail: dr@nn.uk

• Koivula, Department of Ecology and Systematics, Division of Population Biology, P.O. Box 65, FIN-00014 University of Helsinki, Finland E-mail: matti.koivula@helsinki.fi
• Niemelä, Department of Ecology and Systematics, Division of Population Biology, P.O. Box 65, FIN-00014 University of Helsinki, Finland E-mail: jn@nn.fi