Prodrssive soil succession after thinning in northern taiga bilberry spruce forest

Damage to the top soil layers during logging operations can be of various forms (compaction, mixing, pressing, etc.) and of a long-term character. The recovery of the morphological characters and the structure of the soil profile of the native soil can take decades or have irreversible effect. We have studied the soil damage during two-stage (1973 and 2002) conversion thinning operations in the spruce forest with blueberry cover in the northern taiga (tree-length log skidding, TDT-55 tractor). The types of damage that stay during the progressive succession for 50 years and have signs of disturbances due to the logging operations were identified. The mosaic structure of the mixed bedrocks still continues to exist. The forest litter pressed by the heavy machines is replaced by the newly formed one. And at the same time, the organic bedrock of the medium degree of decomposition, which is untypical for the native podzolic soil, is preserved. Mixing by tractor tracks and the formation of mixed bedrock is the most common disturbance of the upper bedrock during logging operations due to insufficient coverage of the skid roads by felling residues. The amount of such damage to the soil is 77 % and 79 % in the skid roads of 1973 and 2002, respectively. But the depth of damage is small, which is 10 cm on average, with fluctuations up to 22 cm. In nano- and micro-depressions, the processes of peat formation and gleying develop. The number of locations with the genesis of bog soils is gradually increasing. On the skid roads of 1973 the proportion of wetlands is 2,5 times higher than in the skid roads of 2002 (86,9 % and 37,3 %, respectively). The long-term soil disturbance in the structure of the soil profile makes it necessary to develop classification approaches to improve the analysis of anthropogenic disturbed soils in cutting areas. The classification units are suggested

An Assessment of Soil Compaction after Logging Operations in Central Amazonia

In the forests of the Amazon Basin, there are still few studies on soil compaction caused by logging activities. This study evaluated an operation located on the property of a timber company in Central Amazonia, which uses harvesting techniques based on the harvesting system developed by the Centre for Agricultural Research in Suriname. The timber-extraction method employed by the timber company consists of three activities: (1) skid trail construction with a track-type tractor, (2) log winching with a winch attached to the tractor, and (3) log skidding with a rubber-tired skidder. Soil bulk density and soil penetration resistance were quantified to 20 cm in depth. After a single tractor ingress and egress for trail construction, the soil incurred an increased root growth-limiting bulk density and penetration resistance. However, log winching did not cause significant soil compaction. The conclusions of the study were: (1) the greatest impact from this harvesting system came from the skid trail construction, (2) the technique of log winching limited forest floor compaction and disturbance that damages forest regeneration, and (3) log skidding during dry soil conditions limited increases in compaction and track formation.

The effects of wood chips and slash usage on skid trail sheet erosion caused by log skidding using a farm tractor

This study investigated the sheet erosion that occurs as a result of log skidding operations using a farm tractor on skid trails and the use of wood chips and slash in order to minimize the soil loss. A total of four blocks (sample fields) were formed in four designated skid trails in the study area and three runoff plots were established in each block. One of the runoff plots was left empty as a control (CNT). Wood chips (C) was placed in the second plot and logging residue slash (S) in the third. A total of 108 water samples were taken from the test sites, 36 from each of the control, wood chips and slash plots. The water samples were brought to the laboratory and placed in an heating oven. After the runoff water was evaporated, the remaining sediment was weighed on a sensitive scale. The specified value was calculated according to the total amount of runoff accumulated in the storage tank and the total suspended sediment it carried. As a result, the amount of the average runoff in the CNT was determined as 6.32 mm/m², in the C as 6.13 mm/m² and in the S as 6.03 mm/m². The average amount of suspended sediment transported in the CNT was found as 2.58 g m^-2, in the C as 1.61 g m^-2and in the S as 2.13 g m^-2. Therefore, the amount of soil loss in the control plots was about 1.2 times higher than in the slash plots and 1.6 times higher than in the wood chips plots. In this study, variance analysis results showed a statistically significant difference between the suspended sediment quantities carried from the plots (p <0.05). This study demonstrated that logging residues can be used to reduce the sheet erosion that occurs in skid trails after log extraction.

A comparison of rubber-tyred and steel-tracked skidders on forest soil physical properties

Compaction of a silty clay loam forest soil was compared for 2 types of log-skidding equipment, a rubber-tyred skidder and a flexible-steel-tracked skidder. Experiments involved the loaded skidders traversing marked laneways at zero, 2, 4, and 10 passes. Compaction was quantified in terms of 3 parameters: (1) bulk density to 25 cm depth measured gravimetrically, (2) penetration resistance using a field penetrometer, and (3) saturated hydraulic conductivity using a field rainfall simulator. Results showed no substantial difference in soil bulk density between the experimental treatments, regardless of skidder type or number passes. Penetration resistance of the traversed laneways was significantly higher than the surrounding undisturbed areas; however, there was no difference between skidder type. Rainfall simulation showed that the saturated hydraulic conductivity of all treatments was strongly reduced by trafficking, although this did not differ with skidder type. The results from this study highlight the dangers in assuming that reduced machine static ground pressures will automatically lead to reduced soil impacts. It is important to note that while this study did not find differences between the 2 skidder types when operated in a similar manner, differences in the operation of the two skidders may also influence impacts on soil properties.

Effects of Soil Disturbance on Hayscented Fern Establishment

A survey conducted in a central Pennsylvania mixed oak stand revealed that hayscented fern reproduced from spores (sexual reproduction) following timber harvesting. Establishment occurred most frequently where the soil had been disturbed by log skidding. Sexually reproduced ferns occurred more frequently where skidding on wet soil during the spring resulted in a high degree of soil disturbance compared with skidding on the same soil during the summer when it was drier. Reduction of logging-related soil disturbance by restriction of skidding on wet soils can decrease the number of microsites favorable for fern development and control the establishment of hayscented fern from spores. North. J. Appl. For. 9(1):29-31.