Quality of timber from drained peatlands
The study indicated that the quality of forests established after
regeneration cuttings in peatlands was almost as good as that of
mineral field forests at corresponding trophic levels. The key factors
were the tree species adapted for the site, the regeneration method
and the management of the young stand.
Of central importance for industry are Scots pine and birch from
thinnings, and saw timber of Norway spruce from final cuttings,
while for long-term evaluations also saw timber of pine and, to
some extent, also birch are important.
The yield of saw logs and construction timber from drained peatlands
was almost invariably less than that from mineral forest lands,
while the remaining stand, after properly applied quality thinning
and strip road planning, provided about as good (and sometimes even
better than expected) starting point for well-managed silviculture
of saw timber. Norway spruce stands from final cuttings in peatland
forests were of equal quality to those in mineral forest lands,
yet the yield of cuttings, stems and saw logs was smaller and the
timber material was more dry-knotted.
Only in exceptional cases Scots pine stands from final cuttings
of peatland forests produced larger amounts of good quality saw
timber; normally the yield of products and their quality distribution
were less than average. Suitable uses are, for example, short construction
and building timber logs, building logs and less valuable construction
and packaging items. Both pine and spruce shared common properties
of stem sweep and crookedness, dry knots and especially, lack of
even quality, because the wood material before and after the draining
was substantially different. Wood developed before the draining
was closely ringed heart-wood, heavy and quite hardy, yet abundantly
knotted and often hard to handle.
Additional information on the project: www.metla.fi/hanke/3258/index-en.htm
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