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Does body posture during tree felling influence the physiological load of a chainsaw operator? Ann Agric Environ Med. 2017; 24(3): 401-405. doi: 10.5604/12321966.1235177 Abstract Introduction and Objectives. Holding determined body postures during work is connected with muscles activity. The more forced the posture, the larger the number of muscles taking an active part in holding and stabilizing the work posture. During logging, the greatest share of awkward (forced) working postures occurs in tree felling by chainsaw. Materials and Method. A group of 10 experienced fellers aged 47.5±7.3 (37 -59-years-old) was studied. Heart rate (HR) was measured during simulation of felling activity in 4 working postures: back bent forward with straight legs (stoop), back bent forward with bent legs (flexed-stoop), squat and kneeling on one knee (half-kneel). Results. The lowest value of HR was noticed for squatting -114.1 bpm, then for kneeling on one knee -116.3 bpm. HR during felling in a standing posture with straight legs amounted to 121.5 bpm and for standing with bent legs 125.3 bpm. For all studied postures the differences in average HR values were statistically significant at p<0.01. Conclusions. A working posture during tree felling by chainsaw has influence on the level of physiological workload of an operator. Standing bent forward body postures cause higher heart response than squatting and half-kneeling.

The aim of this study was to investigate the effect of season of the year on the frequency and degree of damage to residual trees caused during winter and summer timber harvesting operations in young alder stands. Analyses were conducted in pure black alder (Alnus glutinosa Gaertn.) stands aged 38 and 40 years, located in north-eastern Poland. Chainsaw logging was performed in the cut-to-length (CTL) system, while timber was extracted using an agricultural tractor with a trailer with manual timber loading and unloading. Damage caused in the stand as a result of early thinning operations was evaluated in terms of: (1) damage location, (2) wound size, (3) wound depth, and (4) the distance of the damaged tree from the skid trail. Timber harvesting caused damage in 8.3% of trees remaining in the stand. Both the total number of damaged trees (p = 0.001) and the number of trees damaged during felling (p = 0.01) and extraction of timber (p < 0.001) were greater in summer than in winter. Irrespective of the season, two-thirds of all cases of damage were caused during timber extraction, with 67.7% of damage recorded on trunks or root collars and 32.3% on roots. Irrespective of the season and the technological operation, slightly over 50% of cases of damage were small wounds of max. 10 cm 2 . The proportions of medium-sized wounds (11-100 cm 2 ) and large wounds (over 100 cm 2 ) were comparable. The majority of damaged trees (85.1%) were found in the vicinity (<1 m) of the skid trails. The frequency of tree damage near the skid trail was twice as large in summer as in winter (p < 0.001).

Warmer winters may lead to changes in the hibernation behaviour of bats, such as the barbastelle Barbastella barbastellus, which prefers to hibernate at low temperatures. The species is also known for its large annual fluctuations in the number of wintering individuals, so inference about population trends should be based on long-term data. Prior to 2005, analyses indicated stable or even increasing barbastelle population in Poland. We analysed the results of 13 winter bat counts (2005-2017) of the species from 15 of the largest hibernacula, and additional site of 47 small bunkers, in Poland. The total number of wintering individuals remained stable during the study period, because the barbastelle is not a long-distance migrant, this likely reflects the national population trend. On the basis of mean winter air temperatures we divided the country into four thermal regions. Analyses of barbastelle abundance in hibernacula in the four regions revealed a 4.8% annual mean increase in numbers in the coldest region, where mean winter temperatures were below-2˚C, annual mean declines of 3.3% and 3.1% in two warmer regions of western Poland, but no trend in the region of intermediate mean winter temperatures of between-1˚C and-2˚C. Overall, there was a significant, but weak, negative correlation between the abundance of hibernating individuals and the mean winter temperature. On the other hand, the number of individuals hibernating in small bunkers increased, even though the site was located in one of the warm regions. The results indicate a warming climate will likely reduce the use of large, well-insulated winter roosts by species that prefer colder conditions-and that this is already

Accurate log processing by harvesters during bucking is of great importance if round timber is to be fully exploited for maximum value recovery. Logs that exceed the target length can cause difficulties in further processing (e.g., in the pulp industry), while logs which are too short may not be of further use (e.g., boards for pallets). It can be difficult to achieve accurate log lengths due to irregular tree trunk shapes or errors in the measurement system in the harvester head. The objective of the research was to investigate how tree species and log diameter affect bucking length accuracy. The research was carried out in a premature broadleaved stand of birch and aspen in the third age class in the Zaporowo Forest District, northern Poland (54°24′47″N, 20°8′50″E). The thinning operation was carried out in early spring before the start of the growing season and after the snow cover had melted. Trees were cut using a UTC 150-6LS harvester, equipped with a CTL 40HW harvester head designed for hardwood. Pulp wood was harvested from the trees with an intended length of 2.50 m and a tolerance of ±0.05 m. The on-board harvester computer was set to a length tolerance of between 2.46 m and 2.54 m. More than 80% of the thicker birch and aspen logs (d1/2 > 14 cm) met the target length (2.50 ± 0.05 m), while only 70% and 50% of the thinner birch and aspen logs (d1/2 ≤ 14 cm) reached the target. For top logs, a different length tolerance should be applied compared to butt logs in order to achieve higher efficiency in length accuracy.