The effectiveness of harvesting machines, their reliability, and the level of negative environmental impact depends on the degree of adaptation of the equipment to natural-production conditions (NPC). To choose the equipment it is necessary to allocate groups of areas with close NPC. The purpose of the study is to form methodological tools for forest industry typification of forest areas by NPC. It is proposed to carry out the typification of forest areas based on cluster analysis. For this purpose, a methodology has been developed, including: setting the goal of typing areas by NPC; data collection on NPC; conducting cluster analysis; decision making on typification of areas by NPC. The task of cluster analysis is to divide, on the basis of a certain set of data, the set of forest areas into groups with similar NPCs. It is proposed to use Euclidean distances as a measure of belonging to one of the groups, and to determine the data set by indicators describing the NPC. The proposed methodology has been tested on the example of the European North of Russia (ENR). The study showed that three zones can be distinguished in ENR: zone A, including the Murmansk region; zone B, including the Republic of Karelia, the Republic of Komi and the Arkhangelsk region; zone C, including the Vologda region. Additionally, two subzones are distinguished in zone B: the West Karelian Upland and the territories belonging to the Northern, Subpolar and Polar Urals. The proposed methodology allows to increase the degree of formalization and convenience of the typification process of forest areas by NPC, to take into account a wide range of various aspects of natural-production conditions, their probabilistic nature, as well as to flexibly carry out the typification of areas for specific purposes. The research results may be applicable in solving problems of searching for effective technologies and rational parameters of logging machine systems.

The modern technological process of timber harvesting is a complex system both technically and organizationally. Nowadays, the study of such systems and improvement of their efficiency is impossible without the use of mathematical modeling methods. The paper presents the methodology for the optimization of logging operations based on the queueing theory. We show the adapted queueing model, which characterizes the process of logging with the use of a harvesting set consisting of harvesters and forwarders. We also present the experimental verification of the designated model that confirmed mode`s adequacy. The analysis of the effectiveness of the investigated harvesting set was conducted and the recommendations for its optimization were drawn. The research was conducted in the Pryazhinsky District in the Republic of Karelia. We showed that significant improvement of operational efficiency of the investigated harvesting set in the study area cannot be done by adjusting separate machine operations (i.e. by reducing the time of operations execution and their steadiness). However, a change in the number of machines allowed significant improvement in the operational efficiency. The most optimal harvesting set design for the experimental area consisted of two harvesters and two forwarders.Key words: queueing theory; harvester; forwarder; harvesting set; moddeling abstrakt Moderný ťažbový proces predstavuje technicky aj organizačne komplexný systém. Štúdium takýchto systémov a zvyšovanie ich efektívnosti v súčasnosti nie je možné bez využitia metód matematického modelovania. V článku prezentujeme metódu na optimalizáciu ťažbového procesu založenú na báze teórie hromadnej obsluhy. Prezentujeme model hromadnej obsluhy pre zostavu ťažobných strojov pozostávajúcu z harvestorov a vývozných súprav. Okrem toho prezentujeme výsledky experimentálnej validácie navrhnutého modelu, ktoré potvrdili jeho funkčnosť. Výskum bol realizovaný v Prijažinskom regióne v Karélii. Z výsledkov vyplynulo, že významnejšie zlepšenie výkonnosti zostavy ťažbových zariadení v modelovom území nemôže byť dosiahnuté úpravou jednotlivých operácií (napr. skrátením času výkonu operácie). Naopak, zmeny počtu zariadení majú na výkonnosť ťažbovej zostavy zásadný vplyv. Optimálna ťažbová zostava pre podmienky modelového územia pozostáva z dvoch harvestorov a dvoch vývozných súprav.

Natural-production conditions determine operational efficiency of logging machines. This influence needs to be taken into account at different levels of forest management. It is necessary to allocate areas with similar natural-production conditions for effective forest management. It allows simplifying the decision making process for selecting logging technology and machines. The purpose of this study was to establish areas with similar natural and production conditions in the European North of Russia (ENR). In addition, for small enterprises, we recommend logging technologies and logging machines that can be used in established areas. We determined the indicators of the natural-production conditions of ENR regions and compared them. Cluster analysis was used to compare the indicators. We found that ENR can be divided into three main zones A, B, C and two subzones B1 and B2 with similar natural-production conditions. In the zones A, B and the subzones B1 and B2, small logging enterprises should use a harvester and a forwarder. In the zone C, the enterprises can use a logging system including a harvester and a forwarder or a logging system including a feller buncher, a skidder and a processor. The logging system should be based on the light class of logging machines for the zone A, the medium class or the heavy class for the zones B, C and the subzones B1, B2, the heavy class of machines for the zone C.

The objective of the present study is to define mass distribution laws for a bundle of trees using the methods of statistical simulation modeling in order to calculate chokerless skidding tractors lift capacity. For that purpose a statistical simulation model has been developed to generate forest taxation data necessary for complete filling of skidding tractor grapple. The following samples have been obtained from the regions of the European North of Russia based on the model: masses of bundles of trees that can be placed in grapple and values of vertical component of normal load applied to skidding tractor grapple. Minimum values for masses of bundles may vary in the range of 40-87% from the average value. Maximum values may vary in the range of 8-55% from the average value. The difference between the maximum and minimum masses of bundle values increased with increasing the capacity grapple and decreased with increasing the distance from the butt to grapple. We have determined the dependence of bundle mass variation and values of vertical component of normal load applied to skidding tractor grapple on capacity grapple for the regions of the European North of Russia. The studies have allowed determining recommended values for chokerless skidding tractors lift capacity. The analysis of specifications of various models of skidding tractors has shown that clambunk skidders have deficient marginal lift capacity.

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