New Zealand blackwood grower and co-author of the blackwood growers handbook Ian Brown has posted a useful and detailed update on his view of current blackwood management. It makes for thoughtful reading for current and prospective blackwood growers.
Here’s the handbook:
Here’s the update:
I have two comments on Ian’s notes:
Firstly on the issue of blackwood growth rate and wood quality.
Certainly current research shows that growth rate has little to no impact on blackwood wood quality in terms of heartwood colour and basic density.
But my PhD research showed that blackwood wood quality can vary enormously from tree to tree. This is supported by numerous other studies, and is shown to be mostly genetically based.
So if you want good quality wood from plantation blackwood you need to plant good quality genetic stock.
Unfortunately we don’t yet have a blackwood selection and breeding program.
Fortunately the incidence of poor wood quality genes is relatively low.
Also note that research shows there is no correlation between heartwood colour and wood basic density.
Secondly on the issue of pruning height.
Pruning height will obviously affect the final value of the crop and in a big way since most of the value is in the clear pruned log.
Where the site dictates that you can only prune to 4 metres so be it.
But a fully stocked blackwood plantation of 200 trees with an average tree diameter of 60cm dbh pruned to 6 metres will have approximately 300 cubic metres of clear grade premium blackwood per hectare. Only prune to 4 metres and the volume of clear grade blackwood comes down to 215 cubic metres per hectare a reduction of 28%!!
Whilst you have the trees growing you may as well get the most value out of them that you can.
Thanks to Ian Brown for posting his comments.