Value branches
The Pruning ( Wertastung , Aufastung ) is a silvicultural measure to improve the quality of wood from tree trunks to serve. It came up at the end of the 17th century. In tree species that are difficult to clean naturally (especially conifers), i.e. poorly shedding their dead branches , the branches in the trunk area are removed at a young age to prevent ingrowth.
The aim is that the outer 2/3 of the trunk roll are later free of knots. Therefore, the measure must be carried out early, depending on the target diameter of the tree, in some cases with a breast height diameter of around 10 to 12 centimeters. Usually only up to a height of 6 meters is allowed. Only some tree species, such as spruce , larch or Douglas fir , are raised up to 12 meters. It is important that the left green crown is at least 40 percent of the total tree length.
The pruning represents a high investment and is therefore only carried out in well-growing, healthy stands (e.g. pine , Douglas fir, larch or spruce) on so-called Auslese or Z trees . These are used for quality timber production and in the broader portfolio of life exempt from harassing trees until their maturity in situ have gained.
A distinction between Trockenastung that removes the dead branches, and Grünastung be sawn off at the Living Green branches. With the latter, there is a risk that fungi will penetrate the cut and devalue the wood. On the other hand, coating the wounds with tree resin can help.
The pruning is done manually with hand tools such as hand or pole saws or the wing saw , mechanically with climbing saws or chemically with herbicides . In the latter case, water veins are treated, which then die and rot. They can then be removed with a push iron .
literature
- Ernest Asare Abeney: For the pruning of softwood with hand tools . Dissertation. University of Göttingen, Göttingen 1981
Individual evidence
- ↑ Ernest Asare Abeney: On the valuation of coniferous wood with hand tools . Dissertation. University of Göttingen, Göttingen 1981, p. 10.