Researchers set out to answer this question using a wheeled harveter under various stand conditions
Thinning is one of the most important tools of forest management, although thinning operations require the use of machines which ultimately cause damage to the remaining stand. The level of damage largely depends on the human factor, and a tired, less focused operator will create more injuries in the forest. With this in mind, the objectives of this research were to find out whether the probability of tree damage caused by an operator is also affected by: (1) the part of the day (dawn/day/dusk/night), and (2) the cumulative shift time.
The research was carried out in pure pine stands of different ages, density and thinning intensities. Sample plots were selected that had an increasing number of trees per hectare and growing thinning intensities were applied. The same Komatsu 931.1 harvester was used for the thinning operations in each stand.
In all the age classes combined, 5.41% of the remaining trees were wounded. There was a significant influence of the part of the day on the percentage of damaged trees, which was positively correlated with the cumulative shift time. Stand conditions, such as age class and stand density, as well as thinning characteristics (thinning intensity, number of harvested trees and productivity) have different effects on the distribution of damage intensity and on probability.
It was proven that more damage could be observed when light conditions were less favourable or in artificial light, especially at dusk and in younger, or more dense stands. This information may be used during the planning of harvesting operations by programming activities according to age class, stand density and thinning intensity. Based on the results from the study, it is suggested that the operator has short breaks when a higher probability of damage is expected: in the dusk and towards the end of the shift. In this context, one point that could be further examined is the design of extended shift patterns. More information would assist the optimum allocation of the number and the duration of breaks during the shift, with the aim of improving operator focus and thus lowering the probability of tree damage.
The research was titled “Effect of Day or Night and Cumulative Shift Time on the Frequency of Tree Damage during CTL Harvesting in Various Stand Conditions” It was published in Forests 11(7) 2020. The authors were M Bembenek, P Tsioras, Z Karaszewski, B Zawieja, E Bakinowska and P Medersk. Source