Method of variational calculation of influence of the propulsion plants of forestry machines upon the frozen and thawing soil grounds

The forests, which grow in the conditions of complete expansion of the perpetually frozen ground, are unique forests in accordance with their taxational characteristics, quality indicators of the felled timber, and the ecological functions, which these forests perform in the nature. They are characterised by the low biological productivity, as well as by the high vulnerability due to climatological changes and human economic activities. It is fair to say that conservation of the permafrost is one of the main functions of the forests, which grow within the cryolithozone. Because of this, it is necessary to ensure special regimes for the forestry management and forest exploitation within the forests of the cryolithozone. We formulated the variational problem in order to determine influence of the changeability of the physical and mechanical properties of the thawing soil ground at the boundary with the permafrost ground. © 2019 SERSC

Theoretical approaches to logging trail network planning: Increasing efficiency of forest machines and reducing their negative impact on soil and terrain

A good part of the forest that survived active logging during the previous period of industrialization is now in remote areas: on steep slopes, in waterlogged or permafrost areas. There, especially on the slopes, the use of land disproportionately affects ecological processes, specifically hydrological (e.g., peak waves, suspended load, etc.). Organizing off-trail transport of log timber under such conditions is a challenge associated with specific difficulties. Almost any cutting area has sites of different capacity (stand volume per ha), which require the use of high flotation machines and have habitats that cannot be disturbed. The frequency of trips to cutting areas increases with the stand volume in these areas, but there are areas that machines have to drive round. Areas with weak soils need forest machines to carry less weight or to use additional attachments to hold the load. Unfavourable grades need the bundle to be limited in weight to maintain the tractive effort of a skidder. Because this activity is carried out with a high impact on ecology, it calls for a mathematical model and technique to evaluate logging routes and to assess the impact that logging activities have on the forest soil and subsoil and on the forest in general. This paper is devoted to the creation and justification of such a technique and offers an algorithm for careful forest use and forest-friendly logging. © 2019 IOS Press. All rights reserved