Commercial pine plantations have been grown in South Africa for about a century. The first mature sawlogs became available in the 1930, leading to the development of a local sawmilling industry. The South African sawmilling industry is the only major industry of it’s kind in the world based 100% on plantation resources (New Zealand is second with 97%).
Five major pine species are grown. Their mechanical and machining properties are described in tables 2 and 3 below. Pine plantations are typically thinned from 1100 to 250 trees per hectare on the basis of quality selection. Most trees taken out during thinnings are used as pulpwood. The trees are also pruned to seven metres high, usually in three steps, producing knot-free butt logs. The trees at clearfelling age (25 to 35 years) are therefore of exceptional quality.
Until recently, most trees harvested had been grown from unimproved seed. However, nearly all trees planted since the early 1970’s have been of significantly improved wood quality, as a result of a comprehensive tree-breeding program. Within a few years, all trees harvested will come from this improved quality stock.
Extensive sampling and testing and the development of a range of lumber grades with specifications carefully matched to intended end-uses have largely overcome the problems caused by natural variations in growing trees.
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