SHAPING OF THE WIDTH OF TREE RINGS IN SCOTS PINE AS A RESULT OF RESIN TAPPING
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Department of Forest Utilisation, Forest Engineering and Technology, Faculty of Forestry,
University of Agriculture in Krakow
Acceptance date: 2019-11-20
Publication date: 2020-06-23
Acta Silvestria 2019;LVI:49-60
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ABSTRACT
The study material was taken from a stand in the Świerklaniec Forest Division from
a 164-year-old pine stand. Resin was tapped from the stand in question in 1964–1965
in a 2-year cycle. In the case of pines with single resin tapping areas, the notches were
made on trees’ west side. From felled trees, 3 pieces with tapping areas were selected.
Then, 3 wood discs were retrieved from the felled trees at the following heights: discs
marked with A – 1 m from the intersection of the thicker end, within the tapping area
made 47 years earlier (in the 2nd year of tapping) and B – at a distance of 2.60 m and C
at a distance of 3.80 m from the intersection. Rings B and C were above the top edge of
the notch. Samples for comparison were taken with an increment borer from 3 standing,
non-tapped trees on the height of 1.30 m from the base of the trees, from the west and
east. The collected material was analysed by measuring the width of the radial growth
of the trunk of tapped and non-tapped trees from the west and east, taking into account
two zones: 1 – internal, from the core to 1965, i.e. to the second year of tapping, and 2 –
external, from 1966 to 2012.
For all trees, tapped and non-tapped, the average widths of annual growth in internal
zones were larger than in external zones. For tapped trees at the height A, eastwards, i.e.
on the side that is vital for the tree nutrition system, or the vital strip, the average widths of
growth were only 12.3% smaller in the outer zone than in the inner zone. Corresponding
difference in non-tapped trees was as much as 60.4%. In tapped trees on the extension of
the tapping areas (on the west side), at the heights B and C, the average widths of rings in the outer zone were respectively 53.1% and 50.0% smaller than in the inner zone. On the east side, on the extension of the vital strip, at height B, they were smaller only by 37.3%, and at the height C by 39.2% than in the internal zone. This study confirmed the theory of optimising the shape of the tree by increasing the growth in the perimeter part that was not directly affected by mechanical damage; in this case, the damage was caused by resin tapping notches.