Risk assessment of hollow-bearing trees in urban forests.

The paper is a study of risk assessment posed by trees in selected urban woodlands (urban forests) of Warsaw. Two groups of trees were analysed and compared: exhibiting signs of maturity and ageing (hollow-bearing trees with open or hidden cavities and/or caries) and with no signs of decay. 373 individual trees growing near routes frequently or continuously used for recreational purposes were examined using Roloff's vitality classification, and tree risk assessment method, complemented by instrumental studies: a resistance resistograph, pulling tests, and sonic tomography (SoT). The collected data was analysed using the Chi-square test. The results indicate that it is not possible to conclude unequivocally that the presence of hollows in aged trees significantly increases the risk of falling. According to the safety factor results from the SoT and pulling tests, no correlation was demonstrated between the presence of hollow trees and an increase in risk class. The highest proportion of hollow trees (89.42%) was in the low risk group for trunk fracture and uprooting. The results also indicate the coherence of the diagnostic methods to be necessary for providing sufficient information to assess the statics and, ultimately, as our study showed, the protection of hollow trees.

Eye-Tracking in Assessment of the Mental Workload of Harvester Operators.

Harvesting large quantities of timber requires the use of various technical means, including harvesters. The introduction of machine logging has greatly improved safety and reduced accident rates but has also resulted in the risk of musculoskeletal disorders and increased psychological strain. The aim of this study was to determine the level of the mental workload of harvester operators in wind-damaged stands, during daytime and nighttime clearfelling, and during late thinning using the technique of eye-tracking (analysis of saccades and pupil dilation). The highest number of saccades for both felling and processing operations was recorded during daytime and nighttime clearcutting, while the lowest number was recorded in late thinning. For both operations, the highest mean saccade duration was found in late thinning (felling 38.7 ms, processing 36.0 ms) and the lowest in nighttime cutting (felling 33.1 ms, processing 35.5 ms). The highest frequency of saccades in both operations was recorded in clearcut areas during both daytime and nighttime operations. The largest mean pupil diameters during saccades were recorded in night clearfelling plots (felling 5.57 mm, processing 5.52 mm), while the smallest were recorded in plots with windbreaks (felling 2.91 mm, processing 2.89 mm). Comparison of the number, duration, frequency, and time proportion of saccades as well as pupil diameter provided a quantifiable assessment of mental workload in clearcut, wind-damaged, and thinning stands. The indicators analyzed showed that the cutting category can significantly affect the level of mental workload and thus fatigue of harvester operators.

Physiological workload of workers employed during motor-manual timber harvesting in young alder stands in different seasons.

OBJECTIVES: This study examined the physiological strain experienced by workers employed in motor-manual timber harvesting performed in winter and summer, and the applicability of heart rate indices for estimating energy expenditure. MATERIAL AND METHODS: The heart rates (HR) of 2 teams consisting of 2 persons working simultaneously during felling and forwarding, in both winter and summer, were measured. Heart rate at work (HRwork), resting heart rate (HRrest), relative heart rate (%HRR), ratio of working heart rate to resting heart rate, and 50% level were used to estimate the physiological workload in particular jobs. The HRindex (HRwork/HRrest) equation was used to estimate the energy expenditure (EE). RESULTS: For all jobs, significantly higher physiological workload and energy expenditure were recorded during winter. CONCLUSIONS: The season significantly affects the physiological workload during logging operations. If there is no possibility of harvesting wood in summer, in order to limit the workload of workers during winter activity, attention should be paid to the proper organization of work and selection of workers. Int J Occup Med Environ Health. 2022;35(4):437-47.

Cadmium Stress Reprograms ROS/RNS Homeostasis in Phytophthora infestans (Mont.) de Bary.

Heavy metal pollution causes many soils to become a toxic environment not only for plants, but also microorganisms; however, little is known how heavy metal contaminated environment affects metabolism of phytopathogens and their capability of infecting host plants. In this study the oomycete Phytophthora infestans (Mont.) de Bary, the most harmful pathogen of potato, growing under moderate cadmium stress (Cd, 5 mg/L) showed nitro-oxidative imbalance associated with an enhanced antioxidant response. Cadmium notably elevated the level of nitric oxide, superoxide and peroxynitrite that stimulated nitrative modifications within the RNA and DNA pools in the phytopathogen structures. In contrast, the protein pool undergoing nitration was diminished confirming that protein tyrosine nitration is a flexible element of the oomycete adaptive strategy to heavy metal stress. Finally, to verify whether Cd is able to modify P. infestans pathogenicity, a disease index and molecular assessment of disease progress were analysed indicating that Cd stress enhanced aggressiveness of vr P. infestans towards various potato cultivars. Taken together, Cd not only affected hyphal growth rate and caused biochemical changes in P. infestans structures, but accelerated the pathogenicity as well. The nitro-oxidative homeostasis imbalance underlies the phytopathogen adaptive strategy and survival in the heavy metal contaminated environment.

The Influence of the Privatization Process on Accident Rates in the Forestry Sector in Poland.

The aim of this paper is to analyze the changes in accident rates resulting from the privatization of forest operations. Data from the years 1990-2017 were obtained from the Statistical Forestry Yearbooks issued by Statistics Poland, and were analyzed for two periods: the time of intensive privatization (1991-2002) and the post-privatization period (2003-2017). The data from 1990 were treated as a benchmark. There were 14,626 accidents in total, of which 236 (1.61%) were fatal. The non-fatal accident rate in the whole forestry industry showed a decreasing trend in the study period (t = 2.27, p < 0.05). In the case of the fatal accident rate we can observe an upward trend; in the period of intensive privatization the average annual fatality rate was 0.11, and after privatization it was 0.18 (t = -2.68, p < 0.05). In both periods the fatality rate was twice as high in the private forestry sector as in the public sector. The number of working days lost declined in the public sector and increased in the private sector. An accident in the private sector resulted in 20 days' longer absence than one in the public sector. The study confirms that despite economic transition, accident rates in Polish forestry remain a serious issue. The main problem to be addressed is the increase in the fatal accident rate, especially in the private sector.

Switchable Nitroproteome States of Phytophthora infestans Biology and Pathobiology.

The study demonstrates protein tyrosine nitration as a functional post-translational modification (PTM) in biology and pathobiology of the oomycete Phytophthora infestans (Mont.) de Bary, the most harmful pathogen of potato (Solanum tuberosum L.). Using two P. infestans isolates differing in their virulence toward potato cv. Sarpo Mira we found that the pathogen generates reactive nitrogen species (RNS) in hyphae and mature sporangia growing under in vitro and in planta conditions. However, acceleration of peroxynitrite formation and elevation of the nitrated protein pool within pathogen structures were observed mainly during the avr P. infestans MP 946-potato interaction. Importantly, the nitroproteome profiles varied for the pathogen virulence pattern and comparative analysis revealed that vr MP 977 P. infestans represented a much more diverse quality spectrum of nitrated proteins. Abundance profiles of nitrated proteins that were up- or downregulated were substantially different also between the analyzed growth phases. Briefly, in planta growth of avr and vr P. infestans was accompanied by exclusive nitration of proteins involved in energy metabolism, signal transduction and pathogenesis. Importantly, the P. infestans-potato interaction indicated cytosolic RXLRs and Crinklers effectors as potential sensors of RNS. Taken together, we explored the first plant pathogen nitroproteome. The results present new insights into RNS metabolism in P. infestans indicating protein nitration as an integral part of pathogen biology, dynamically modified during its offensive strategy. Thus, the nitroproteome should be considered as a flexible element of the oomycete developmental and adaptive mechanism to different micro-environments, including host cells.

Does body posture during tree felling influence the physiological load of a chainsaw operator?

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. MATERIAL AND METHODS: 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.

Nitric oxide implication in cadmium-induced programmed cell death in roots and signaling response of yellow lupine plants.

The sequence of events leading to the programmed cell death (PCD) induced by heavy metals in plants is still the object of extensive investigation. In this study we showed that roots of 3-day old yellow lupine (Lupinus luteus L.) seedlings exposed to cadmium (Cd, 89µM CdCl(2)) resulted in PCD starting from 24h of stress duration, which was evidenced by TUNEL-positive reaction. Cd-induced PCD was preceded by a relatively early burst of nitric oxide (NO) localized mainly in the root tips. Above changes were accompanied by the NADPH-oxidase-dependent superoxide anion (O(2)(·-)) production. However, the concomitant high level of both NO and O(2)(·-) at the 24th h of Cd exposure did not provoke an enhanced peroxynitrite formation. The treatment with the NADPH-oxidase inhibitor and NO-scavenger significantly reduced O(2)(·-) and NO production, respectively, as well as diminished the pool of cells undergoing PCD. The obtained data indicate that boosted NO and O(2)(·-) production is required for Cd-induced PCD in lupine roots. Moreover, we found that in roots of 14-day old lupine plants the NO-dependent Cd-induced PCD was correlated with the enhanced level of the post-stress signals in leaves, including distal NO cross-talk with hydrogen peroxide.