Farm Forestry New ZealandWide planting does not work
Ken Jones and Neil Cullen, New Zealand Tree Grower February 2008.
In the 1980s the wide spacing of radiata pine was a popular strategy with farm foresters. The advocates of this system believed that the reduced establishment and tending costs and greatly increased grazing obtained in such blocks would more than offset any disadvantages.
Agro-forestry, as it was also known, soon fell out of favour as the problems became more apparent. With no pressure from adjacent trees, heavy branching was common and a regular and precise pruning regime was essential to achieve good butt logs. Even if the forester got the pruning right, the top log with big branches and no peer pressure to force it up was of low value.
Final results
Now that the wide spaced blocks are being harvested the final results of this experiment are available. A recent harvest of a 4.5 hectare wide planted block illustrates the disadvantages. Planted in a gorse gully in 1981 by award winning South Otago farm foresters, Don and Joan Gordon, the trees have recently been harvested by Mike Hurring Logging using a small hauler. A nearby block that had been traditionally planted, pruned and thinned at the appropriate time showed stark comparisons when harvested last year. There was a big difference in returns, even allowing for cost increases and the virtual collapse of the market for poorer grades.
The wide-spaced planting finished up with 155 stems per hectare while the traditional planting had about 320 stems per hectare. There were about 200 tonnes per hectare more on the traditional block and the value per hectare was more than double. The log above the prune in the wide spaced planting saw much of the drop in value, but logging and transport costs were also a bit higher. There was luck with the weather on both blocks and no new roading was necessary. Nett revenue for the wide spaced planting was $9,632 per hectare, which was a bit disappointing, considering the diameter of the butt logs, though some had sweep.
Lack of volume
The biggest problem therefore with wide spaced radiata is the lack of volume of logs. This means with increasing costs of harvesting the nett returns are going to be significantly less than conventionally stocked blocks. You cannot, it seems, have it both ways.
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