The significance of above-ground biomass, moisture content and mechanical properties of peat layer on the bearing capacity of ditched pine bogs

Abstract

The significance of above-ground biomass, moisture content and mechanical properties of peat layer on the bearing capacity of ditched pine bogs Uusitalo J., Ala-Ilomäki J. (2013). The significance of above-ground biomass, moisture content and mechanical properties of peat layer on the bearing capacity of ditched pine bogs. Silva Fennica vol. 47 no. 3 article id 993. 18 p. AbstractIntensive utilisation of peatland forests calls for logging activities to be increasingly carried out in conditions other than those in harsh winter. The low bearing capacity of peatlands forms a severe obstacle for the prevailing harvesting machinery. The aim of this study was to clarify and quantify the significance of above-ground biomass, brash mat, moisture content and mechanical properties of peat layer on the bearing capacity of pine bogs. In-situ driving tests were conducted in Western Finland on a pine bog covering a large variation of growing stock. Portable tools were tested for measuring strength properties of the top layer of peat. According to the results, shear modulus of top layer of peat, volume of trees and the existence of cutting debris are the most important factors affecting bearing capacity. Spiked shear vane was shown to be a promising tool in predicting the strength properties of peat soil.

Estimating the Rut Depth by UAV Photogrammetry

“…Ruts are formed when the loading exerted by the forest vehicle exceeds the strength of the soil [12][13][14]. The bearing capacity depends on various static and dynamic factors: e.g., soil type, root density, slope and other micro-topographic water dynamics and frost state.…”

“…The bearing capacity depends on various static and dynamic factors: e.g., soil type, root density, slope and other micro-topographic water dynamics and frost state. As a result, both the spatial and temporal variation in trafficability is extremely large [14,15]. An easily collected and extensive dataset on rut depths that covers field measurements over several test sites and various weather conditions is thus needed for any attempts to model forest terrain trafficability [16].…”

Performance of weather parameters in predicting growing season water table depth variations on drained forested peatlands – a case study from southern Finland

“…There is, however, a problem in the utilization of the timber resources in the drained sites. The generally poor bearing capacity of peat makes harvest conditions more demanding than those in the upland sites (Uusitalo and Ala-Ilomäki 2013). Due to the poor support of peat for harvesting machines, peatland harvesting has been traditionally done in seasons when the soil is frozen to prevent machines from sinking.…”

Projected decrease in wintertime bearing capacity on different forest and soil types in Finland under a warming climate

“…Consequently, peatlands consist nowadays one third of the Finnish forestry area and one fourth of the growing stock volume (Ala-Ilomäki et al, 2011). In increasing the wood harvesting, more intensive utilization of drained peatland forests has the largest potential (Ala-Ilomäki et al, 2011), because of a pronounced reduction of suitable logging sites on upland (mineral) soils (Uusitalo and Ala-Ilomäki, 2013). However, more intensive utilization of peatlands is a controversial 25 issue.…”

“…However, more intensive utilization of peatlands is a controversial 25 issue. Peatlands representing sensitive forest sites are generally characterized by the most difficult forest harvesting conditions (Nugent et al, 2003;Uusitalo and Ala-Ilomäki, 2013;Uusitalo et al, 2015a). Moreover, in addition to the increasing demand of wood harvesting from drained peatlands, there exists a pressure to restore drained peatlands to natural state in order to maintain biodiversity and prevent carbon loss from peatlands (Komulainen et al, 1999;Carroll et al, 2011;Pitkänen et al, 2013).…”