Response of vegetation and soil biological properties to deformation in logging trails in drained boreal peatland forests

In the boreal region, peatland forests are a significant resource of timber. Under pressure from a growing bioeconomy and climate change, timber harvesting is increasingly occurring over unfrozen soils. This is likely to cause disturbance in the soil biogeochemistry. We studied the impact of machinery-induced soil disturbance on the vegetation, microbes, and soil biogeochemistry of drained boreal peatland forests caused by machinery traffic during thinning operations. To assess potential recovery, we sampled six sites that ranged in time since thinning from a few months to 15 years. Soil disturbance directly decreased moss biomass and led to an increase in sedge cover and a decrease in root production. Moreover, soil CO2 production potential, and soil CO2 and CH4 concentrations were greater in recently disturbed areas than in the control areas. In contrast, CO2 and CH4 emissions, microbial biomass and structure, and the decomposition rate of cellulose appeared to be uncoupled and did not show signs of impact. While the impacted properties varied in their rate of recovery, they all fully recovered within 15 years covered by our chronosequence study. Conclusively, drained boreal peatlands appeared to have high biological resilience to soil disturbance caused by forest machinery during thinning operations.

Determining Harvester Productivity Curves of Thinning Operations in Birch Stands of Central Europe

Silver birch (Betula pendula Roth) is a popular tree species forming stands in nearly the whole of Europe. In Poland, birch is one of the most representative broadleaved species growing on rather poor soils, very often as a mix species with Scots pine (Pinus sylvestris L.). In Central Europe, birch forms trunk often with sweeps, and at the older age with thick branches. Due to that, a harvester thinning operation in birch stands can be challengeable when trying to process logs from the top part of trees, which can finally impact on productivity. The objective of this research was to determine harvester productivity for birch with particular attention to production of logs from the top part of a tree. The research was carried out in stands of North and North-West Poland. All together 21 tests were completed in 16 stands, in which 9 harvesters were used (8 different models). The mean diameter of harvested trees was 23.7 cm with the mean height of 21.7 m. Obtained productivity without delays was on average 21.98 m3 h-1 and varied from as low as 5.14 to maximum 44.66 m3 h-1, and depended mainly on harvested tree size. It was also confirmed that top diameter of the last log depended on diameter at breast height (DBH). The model developed based on that relationship can be used for prediction of biomass volume from birch stands when harvesters are used for thinning.

Detection of Oil Tank from High Resolution Remote Sensing Images using Morphological and Statistical Tools

Oil tank is an important target and automatic detection of the target is an open research issue in satellite based high resolution imagery. This could be used for disaster screening, oil outflow, etc. A new methodology has been proposed for consistent and precise automatic oil tank detection from such panchromatic images. The proposed methodology uses both spatial and spectral properties domain knowledge regarding the character of targets in the sight. Multiple steps are required for detection of the target in the methodology – 1) enhancement technique using directional morphology, 2) multi-seed based clustering procedure using internal gray variance (IGV), 3) binarization and thinning operations, 4) circular shape detection by Hough transform, 5) MST based special relational grouping operation and 6) supervised minimum distance classifier for oil tank detection. IKONOS and Quickbird satellite images are used for testing the proposed algorithm. The outcomes show that the projected methodology in this paper is both precise and competent.

Vibration and Noise Exposure during Pre-Commercial Thinning Operations: What Are the Ergonomic Benefits of the Latest Generation Professional-Grade Battery-Powered Chainsaws?

In order to compare the vibration and noise exposure of STIHL’s battery-powered MSA 220 C and the combustion driven MS 201 C, a professional operator was monitored during a pre-commercial thinning operation in a twenty-year-old hardwood stand. The vibration levels were measured with a tri-axial accelerometer on the front and rear handle of both the chainsaws, and assigned to five different work elements using a video documentation. Additionally, noise levels were recorded in one-minute intervals, with a dosemeter worn by the operator. The results show that battery-powered chainsaws, when compared to combustion-driven chainsaws, can reduce the daily vibration exposure by more than 45% and the noise dose by about 78.4%, during pre-commercial thinning tasks. Replacing combustion-driven chainsaws with battery-powered ones is therefore generally recommended, to reduce occupational health risks for operators, in this respect. However, the daily vibration exposure of about 2.42 m/s2, caused by the battery-powered chainsaw on the front handle, is still very close to the daily exposure action value set by the EU directives for health and safety requirements. The daily noise exposure of 89.18 dB(A) even exceeds the upper exposure action value. Consequently, a further reduction in the vibration exposure during work is desirable. With respect to noise exposure, additional measures must be implemented for conformity with the current safety standards, making the use of hearing protectors mandatory for electric chainsaws, too.

Stamping a medium – sized cartridge blank from low – carbon steel

The work is devoted to obtaining a medium – sized cartridge blank from low-carbon steel. The sequence of punching transitions includes a hot back- extrusion operation, two cold draw – thinning operations, and a cold crimp operation. Modeling using the finite element method established: efforts and specific forces during operations, thermal effect during shaping, shape and size of semi – finished products with distributions of strain intensity. An elastoplastic metal model was used, which made it possible to reveal the forces of extracting the tool from deformed semifinished products and the forces of removing semifinished products from the matrix. A hollow semifinished product with the required dimensions of a protrusion on the bottom part from the side of the cavity and a protrusion on the end for forming a flange is obtained by reverse extrusion. The possibility of carrying out the first drawing operation with thinning through three sequentially located matrixes is shown. After this operation, annealing of the semi-finished product is required to restore plasticity. In the second operation of drawing with thinning and additional stamping of the bottom part, the final dimensions of this part from the side of the cavity and the shaping of the flange on the lateral surface of the semi-finished product are provided with the creation of a macrostructure to ensure the required operational properties. The shape and dimensions of the wall of the semi-finished product after the second drawing, the distribution of the intensity of deformations in it are determined from the condition of reaching the final dimensions and mechanical properties of the cartridge blank at the last crimping operation. For this, the deformations obtained as a result of the second drawing are taken into account when modeling the crimp. The proposed technology for stamping a blank of a sleeve can be implemented on a universal press – forging equipment, has a high productivity and minimizes mechanical processing.

EVALUATION OF DAMAGE OF ROUNDWOOD ASSORTIMENTS CAUSED BY VARIED CONSTRUCTION, TECHNICAL SOLUTIONS AND CONDITIONS OF HARVESTER HEAD FEED ROLLERS

The purpose of this study was to evaluate the depth of damages caused by harvester head feed roller spikes to birtch veneer logs, harvested according to top diameter group (18x25cm, 25cm), spruce sawlogs (6x10cm), spruce and pine sawlogs according to top diameter group (10x14cm, 14x18cm). Thirteen technical solutions and conditions of the harvester head soft feed rollers (Moipu Standard, Rib), standard feed rollers (Multi-Tree Handling (MTH), Steel Thumbnail) and agreesive feed rollers (TP) were tested in this study.Regulation parameters of hydraulic system and angles of delimbing knife blades during the harvesting of stems in different woodland types and seasonality using single grip harvesters: John Deere 1270E, John Deere 1070E and John Deere 1070D equipped with harvester heads: H754; H480C and H460 were examined in clearcutting and thinning operations in twenty four wood felling sites in Kurzeme and Vidzeme region of Latvia.

Mechanical Thinning of Mandarins with a Branch Shaker

Thinning is the process of removing some flowers or fruit to increase fruit size at harvest. In the Valencia region of Spain, the thinning operation for citrus fruit (Citreae) is performed for some mandarin varieties. This is always performed manually; however, this method is very expensive. The goal of this research study was to assess the mechanical thinning of mandarin (Citrus reticulata) using a hand-held branch shaker. Different thinning treatments were conducted over a 3-year period. The gasoline-powered branch shaker was capable of detaching fruit four- to five-times faster than manual thinning. Final fruit size was significantly higher using manual and mechanical thinning compared with a no thinning treatment. Similar final fruit size was obtained with manual and mechanical thinning. However, no significant differences were found in final fruit yield by weight among no thinning, mechanical thinning, and manual thinning treatments. The use of a branch shaker could be recommended for thinning operations to increase efficiency, reduce labor costs, and obtain larger and higher-quality fruit.

Family Forest Owners’ Perception of Management and Thinning Operations in Young Dense Forests: A Survey from Sweden

Family forest owners (FFOs) own 48% of Sweden’s productive forest land and are responsible for 59% of the annual gross felling. They are thus important suppliers of raw materials to the forest industry and the energy sector. Environmental goals on the national and international level promote an increased use of renewable resources in order to replace fossil-based fuels, but since the current supply of forest products is already fully utilized by the industry, there is a need to find new types of biomass assortment. One way to increase the biomass supply is to replace traditional pre-commercial thinning operations, where fallen stems are left in the forest to rot, with whole-tree harvesting of small-diameter trees using novel technologies and methods. This will however require willingness of the FFOs to shift their management practices. The objectives of this study were, therefore, to elucidate FFOs’ perceptions of management and thinning operations in young dense forests, identify if there are differences depending on their demographic backgrounds, and clarify which factors could potentially affect their willingness to implement whole-tree harvesting in young dense forests. Data were collected through a survey administered to a random sample of 842 FFOs, with a response rate of 53.4% (n = 450). The results show that FFOs in general are positive towards implementing whole-tree harvesting in young dense stands, and are often also willing to promote the development of suitable stands. Factors such as forest size, geographical location, distance from home to their forest, degree of self-employment and current need for cleaning were found to significantly affect their attitudes. The study highlights that the development of cost efficient harvesting techniques and working methods is important if the industry wants to increase the FFOs’ willingness to engage in whole-tree harvesting in young dense forest stands and thereby increase the supply of biomass.