Assessment of Felling Technique, Based On Stump Dimensions and Individual Logger Characteristics

In Slovenia, professional loggers are required to hold a national professional logger's qualification awarded by the National Centre for Vocational Training. The main purpose of these standards is to demonstrate a logger's ability to fell a tree safely. In our study, we measured the dimensions of each logger's stump. We also measured their personal characteristics and habits using pre-designed questionnaires. Twenty-five loggers were examined, each felling 5 trees, and one logger fell 8 trees. Prior to felling, each logger completed a questionnaire, detailing their personal characteristics and daily habits. The stumps were measured using eight different parameters, including the angle of the notch, lenght of top and bottom cuts, height and width on right and left side of the hinge and diameter of the stump. 60 % of the stumps had a correct notch angle between 35-45°. Notch angle is not statistically correlated with stump diameter. 77 stumps had the correct size of the bottom cut, which must be 1/6 to 1/3 of the stump diameter. Out of 128 felled trees, 110 stumps had a hinge and 18 had no hinge. The size of the hinge has a positive correlation with the diameter of the stump. The average width of the hinge measured 9 % of the stump diameter, whereas the prescribed width should be at least 10 %. The correct height of the hinge should be 1/10 of the stump diameter according to the standards. Our results showed that 67 % of all trees had the correct height of the hinge. Out of 25 loggers, 10 do not have breakfast before work, while the remaining 15 have breakfast every day. The amount of liquid consumed in summer is significantly different from that in winter (p=>0.001). According to our survey, 73 % of all loggers reported feeling tired after work every day. In addition, 43 % of them also feel tired in the morning before work, while 52 % do not feel tired and 5 % feel tired occasionally. 48 % of loggers described themselves as introverted, observant, pessimist (phlegmatic person), 32 % as extroverted, narrative, optimist (sanguinee person), 12 % as extroverted, hardworking, optimist (colerik person) and 8 % as introverted, thinker, pessimist (melanholic person).