Analysis of Accuracy of Evaluating the Structure of a Harvester Operator’s Workday by Work Sampling

The study covered an analysis of the accuracy level of measuring time within a working shift using the method of regular snapshot observation at a harvester operator’s worksite in Scots pine stands. A conformance level of the analyzed methods was evaluated through assessing the accuracy of rectilinear fitting of time structures, established using the photography of work day method and snapshot observations. The accuracy of snapshot measurements performed in 3-minute intervals was determined as high, exceeding 95%. Increasing the time interval between observations to 10 or 15 minutes resulted in higher estimation error in snapshot observation time, ranging between 5 and 10% for late thinned and clear-cut stands. The accuracy of evaluating proportions of specific work times within a working shift, in regular snapshot observations, was correlated with work cyclicality. The strongest work cycle in thinned stands consisted of 43 activities, with total duration of 13 minutes, whereas in clearcut stands it comprised 45 activities, with total duration of 15 minutes. One of the advantages of the described method, apart from its lower labour intensity as compared to working day photography, was the possibility to assess labour time and breaks as well as estimate the share of downtime

Design of a Planting Module for an Automatic Device for Forest Regeneration

Forest regeneration by means of seedlings grown in container nurseries is usually performed manually with the use of the standard dibble bar or the tube dibble. Manual placement of a large number of seedlings in the soil requires a lot of work. Manual removal of the soil cover and digging the soil in spots with a diameter of 0.4 m requires, under average conditions, about 38 man-hours/ha, while planting with a dibble bar requires about 34 man-hours/ha. Additional work time is needed to carry seedlings over an area that is being afforested. At present, forestry does not have automatic planters that would enable the establishment of forest cultures. The aim of the paper is to present the concept of an autonomous robot and an innovative technology of performing forest regeneration and afforestation of former agricultural and reclaimed areas. The paper also presents the design solutions of the key working unit, which is a universal, openable dibble, cooperating with a three-toothed shaft to prepare a planting spot. The solution proposed enables continuous operation of the machine, i.e. without the need to stop the base vehicle

Time Consumption of Skidding in Mature Stands Performed by Winches Powered by Farm Tractor

The aim of the present research was to determine the characteristics of time consumption in skidding by winch. The research was conducted in pine, fir, spruce and beech mature stands. It covered the operation of skidding from the stand to the skid trail at the distance of up to 50 m. A time study was performed for skidding operations, timber volume and thinning intensity. The average time consumption of skidding in the operational time, assessed in the examined mature stands, amounted to approximately 18 min/m3. Significant differences were observed in frequency levels between early thinnings (24 min/m3) and late ones (13 min/m3). The operational time structure for skidding by winch was characterized by a large share of auxiliary time: 71%. Out of that time, 30% was used for attaching and detaching the load and 36% for the transfer. Approximation was also done of the multiple regression equations. The equations described changes in skidding time consumption, i.e. the Empirical Efficiency Index (EST). The changes depended on environmental factors (stand, cutting category), elements of the working day structure (the share of a given time category in a shift) and task intensity (ratio of the number of harvested trees per area unit). The strongest correlations between the EST and the analyzed variables were observed for the factors related to the percentage of time required for attaching and detaching the load and factors related to operation intensity

The accuracy of measurements in a time study of harvester operations

Abstract Background Work time measurements are the starting point for any calculation of unit costs of machine exploitation; therefore, the accuracy of evaluating these costs determines the economic effectiveness of technological solutions employed in forest work. The research aimed to determine the level of measurement error of harvester operation times by means of a chronometric method. Methods Different methods for measuring the components of the work cycle in cut-to-length harvesting operations were compared. These operations consisted of a thinning and a clear-cut harvesting operation in two Scots pine (Pinus sylvestris L.) stands in central Poland. The average duration of a work cycle was determined from cumulative timing using either the on-board PSION microcomputers or analysis of video footage. Results from these two methods were compared with the standard method used in work study which is snap-back timing (i.e. the timer is reset at the end of each activity within the work cycle, the average time for each activity calculated and then summed to give the average cycle time) using the PSION microcomputer. Results The average duration of the work cycles estimated from cumulative timing of video footage were 55.0 and 52.3 s for the thinning and clear-cut operations, respectively. The cumulative timing method using the PSION on-board computer underestimated these cycle times by ca. 14% in thinning operations and by 22% in clear-cut operations. The snap-back timing method, which measures the duration of certain operations separately, underestimated the average work cycle time in the clear-cut operation by 6% but overestimated it by ca. 12% in the thinning operation. In both operations, most of the difference in work cycle time estimates were due to differences in the time recorded for delimbing and bucking activities. Conclusions The accuracy of work time measurement taken using the standard methods—snap-back timing—depends on the variability of work cycles. The hitherto employed method of snap-back timing is more accurate than the cumulative timing method with respect to both stable and more changeable work cycles

The effect of stand origin on the wood structure of Norway spruce

A study was carried out to compare the annual ring width, latewood share and density of spruce wood from the north eastern a nd south w estern ranges of Norway spruce. Twelve trial plots were located in the north eastern range, while within the south w estern range eight trial plots were established in the Sudeten Mountains and twelve trial plots in the Carpathian Mountains. On ev ery trial plot fifteen spruce trees were chosen, from which increment cores were sampled using a Pressler borer. Next, the increment cores had their surfaces smoothed and measurements were made of the width of annual rings, latewood zones and the share of latewood. Then the cores were divided into 2 cm sections, for which the relative wood density was determined. The analyses indicate that annual rings were wider in trees growing within the north eastern range than in those from the south western range an d the Kruskal Wallis test showed the differences to be statistically significant. T he latewood share followed an opposite pattern: t he wood from the Mazury region had a higher proportion of latewood than the wood from the mountainous areas and the statist ical test again indicated that the differences were significant. The analys i s of wood density showed slight differences between the density of wood from the north eastern and south western ranges, but in this case the Kruskal Wallis test showed the differe nces to be statistically insignificant

Evaluation of CRISPR/Cas9 Constructs in Wheat Cell Suspension Cultures

Despite intensive optimization efforts, developing an efficient sequence-specific CRISPR/Cas-mediated genome editing method remains a challenge, especially in polyploid cereal species such as wheat. Validating the efficacy of nuclease constructs prior to using them in planta is, thus, a major step of every editing experiment. Several construct evaluation strategies were proposed, with PEG-mediated plasmid transfection of seedling-derived protoplasts becoming the most popular. However, the usefulness of this approach is affected by associated construct copy number bias and chromatin relaxation, both influencing the outcome. Therefore, to achieve a reliable evaluation of CRISPR/Cas9 constructs, we proposed a system based on an Agrobacterium-mediated transformation of established wheat cell suspension cultures. This system was used for the evaluation of a CRISPR/Cas9 construct designed to target the ABA 8′-hydroxylase 1 gene. The efficiency of editing was verified by cost-effective means of Sanger sequencing and bioinformatic analysis. We discuss advantages and potential future developments of this method in contrast to other in vitro approaches

Evaluation of CRISPR/Cas9 Constructs in Wheat Cell Suspension Cultures

Despite intensive optimization efforts, developing an efficient sequence-specific CRISPR/Cas-mediated genome editing method remains a challenge, especially in polyploid cereal species such as wheat. Validating the efficacy of nuclease constructs prior to using them in planta is, thus, a major step of every editing experiment. Several construct evaluation strategies were proposed, with PEG-mediated plasmid transfection of seedling-derived protoplasts becoming the most popular. However, the usefulness of this approach is affected by associated construct copy number bias and chromatin relaxation, both influencing the outcome. Therefore, to achieve a reliable evaluation of CRISPR/Cas9 constructs, we proposed a system based on an Agrobacterium-mediated transformation of established wheat cell suspension cultures. This system was used for the evaluation of a CRISPR/Cas9 construct designed to target the ABA 8′-hydroxylase 1 gene. The efficiency of editing was verified by cost-effective means of Sanger sequencing and bioinformatic analysis. We discuss advantages and potential future developments of this method in contrast to other in vitro approaches