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Intensifying the management of protection forests in the Alps

Mihelič M., Spinelli R., Poje A.

Drewno : prace naukowe, doniesienia, komunikaty

2018

vol. 61, nr 201

23--37

In the Alps, forests are generally multi-functional, and they are classed according to their primary role as production, protection or recreation forests. The dominance of one of these roles does not exclude all the others, although it shapes management, which must reflect the primary role of each forest. That is also the case of protection forests, which must be managed for their secondary production and recreation roles as well. What is more, management is a vital requirement because it supports forest health, and therefore periodic harvesting remains a necessity. However, the physical conditions that characterize a protection forest (e.g. extremely steep terrain, sensitive soil, remote location etc.) and the prescriptions of a specifically designed silviculture tend to constrain harvesting and make it especially difficult. Special harvesting equipment and novel approaches to harvesting are required in order to achieve environmental, social and financial sustainability. This study reports about cable yarding in a protection forest, under conditions that are representative of the challenges encountered when negotiating this forest type. The productivity of the yarding operation was 6.1 m3ub ub SMH-1 for the yarding distance of 135 m, an average load of 0.88 m3 and a lateral distance of 20 m. Of the remaining trees, 27.1% were damaged during forest operations due to felling, log contact or falling rocks. Falling rocks have a great influence on log quality and value. Consequently, 73% of conifers and 90% of broadleaves are C class logs or other lower grade wood, making a large impact on the economy of the operation.

Healing rate of logging wounds on broadleaf trees in Hyrcanian forest with some technological implications

Tavankar F., Picchio R., Nikooy M., Lo Monaco A., Venanzi R., Iranparast Bodaghi A.

Drewno : prace naukowe, doniesienia, komunikaty

2017

vol. 60, nr 199

65--80

The wound healing rate (WHR) was investigated in 234 wounded trees in Iranian forests and was found to range from 6.4 to 24.0 mm·yr-1. Tree species, slope aspect, elevation, wound age, and wound type had significant effects on the WHR. The mean of the WHR in the Fraxinus excelsior (24 mm·yr-1), Alnus subcordata (18.9 mm·yr-1) and in the Fagus orientalis (17.9 mm·yr-1) were significantly higher than in the Acer insigne (15.7 mm·yr-1), Acer cappadocicum (14.6 mm·yr-1), Carpinus betulus (13.7 mm·yr-1), and Tilia begonifolia (6.4 mm·yr-1). In addition, the mean of the WHR on northern slopes (17.5 mm·yr-1) was significantly higher than on southern slopes. Moreover, the parameters that positively influenced tree growth showed a similar effect on the wound healing rate. The WHRs of 5-, 10- and 15-year-old wounds were 19.3, 16.9 and 10 mm·yr-1, respectively. The WHR increased the higher the wound from ground level. The WHR for horizontal wounds (18.4 mm·yr-1) was significantly higher than for vertical wounds. The highest WHR was estimated in a stand with a canopy closure of 60-80%. The WHR decreased according to increasing wound width. Wounds affect future income, lowering the number of trees that potentially provide a higher quality of saw and veneer logs.

Damage caused by harvester head feed rollers to alder, pine and spruce

Karaszewski Z., Łacka A., Mederski P. S., Noskowiak A., Bembenek M.

Drewno : prace naukowe, doniesienia, komunikaty

2016

vol. 59, nr 197

77--88

The harvester head causes damage to the bark and wood on the lateral surface of the processed assortment. The severity of the damage may be influenced by the construction of the harvester head and tree species characteristics, such as bark thickness and wood hardness. The study aimed to recognise and compare damage caused to hardwood and softwood. Wood from alder, pine and spruce was harvested using a Valmet 911.4 harvester equipped with a 360.2 head. Logs measuring 2.40 and 2.50 m in length were used in this study. The depth of the damage caused by the feed roller spikes was measured using a digital caliper. Comparison of these defects across the three species revealed that as bark thickness increased so the depth of damage to the timber decreased. Damage to the alder logs in the form of dents and gouged timber fibres was shallow: from 1.7 to 3.7 mm, and significantly less than that to the softwood logs: in the pine from 5.9 to 7.8 mm, and in the spruce from 3.9 to 5.6 mm. Damage to the middle and top logs for each species was similar and depth varied little along the entire length of the processed assortment. Such damage only slightly lowered the quality of the alder wood, which had the thickest bark. Application of the Valmet 911.4 harvester caused less damage to the alder wood than to the softwood (pine and spruce).