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Forests play an irreplaceable role in linking the water cycle with the functions of soil. Soil water not only enhances the stability of forests, but also its runoff and evaporation affects the growth of plants in different ecosystems. The forest soil water balance is contextualized within the immediate and more global landscapes, in terms of relations of water to the soil environment and bedrock, participation in the local water cycle within a catchment basin and in the global cycle between ecosystems. Modifications by human civilization can have significant impacts, including erosion intensification, eutrophication, salinization, spreading of singlespecies plantations, and regime shifts. Forests regulate the movement of water in the soil environment by reducing the intensity of runoff. Such moderated runoff prevents the occurrence of flash floods, maintaining continuous availability of water for plant and human use. Participation of soil water in the cycling of elements in forests is modified by soil organic matter balance. The preservation of hydric functions in forest soils depends on prioritization of water balance restoration in every catchment basin enclosing the local element cycle. More fundamentally, the development of a synergistically interlinked system, centered around the soilforest-water-civilization nexus, must become an urgent priority.

Abstract:The exact data from the field of soil mechanics from specific forest stands exposed to forestry mechanization operation were obtained. Field surveys were performed on four study plots within the Křtiny Training Forest Enterprise, Masaryk Forest, followed by laboratory analyses of the collected soil samples aimed at evaluation of the impacts of Zetor 7245 Horal System, PONSSE ERGO 16 harvester and Gremo 950 forwarder on the compaction of upper soil horizons as well as on the dynamics of soil saturated hydraulic conductivity. A specific objective of the performed investigation was to assess the influence of the used hauling/skidding technology on measurable parameters of soil mechanics with the emphasis on a possibility to apply the Guelph permeameter for direct study of soil saturated hydraulic conductivity. In the measurement points affected by machinery operation, the impact of the changed soil structure on the values of saturated conductivity is very well noticeable -on study plots No. 3 and 4, the values decreased by one order of magnitude from 0.7 × 10 -5 m·s -1 to 0.09 × 10 -5 m·s -1 : specifically, (i) on study plot No. 3 and from 6.9 × 10 -5 m·s -1 to 0.7 × 10 -5 m·s -1 , and (ii) on study plot No. 4; on study plot No. 2 even by two orders, i.e. from 1.6 × 10 -5 m·s -1 up to 0.03 × 10 -5 m·s -1 .After the operation of a universal wheeled tractor at the Babice nad Svitavou locality, the situation partially improved by one order to 0.3 × 10 -5 m·s -1 , similarly like at the Rudice locality to 1.5 × 10 -5 m·s -1 . Significant changes were found in both surface and subsurface horizons. Field-saturated hydraulic conductivity indicates also a reduction of the pore volume after machinery traffic; however, tendencies towards restoration of the original state were detectable as soon as after six months.