by Ian Brown
For over 30 years I have been on a learning curve for blackwood. I planted my first blackwoods in 1980 on a small abandoned farm property I had bought in the far north of New Zealand. It was a long way from home, but it was cheap, and the nearby coast was appealing for family holidays. It was located in an elevated valley, sheltered from prevailing winds, an adjacent range provided good rainfall, and had clay loam soils based on ancient volcanics. In response to a recent study carried out by Ian Nicholas at Forest Research, who had been working on a project to select a limited number of species to supplement our monoculture of radiata pine, my brother and I decided to trial some alternative species, including blackwood.
Blackwoods have been planted in New Zealand from the 19th century. It had been generally assumed that to produce good form they should be interplanted with another species, and many had been planted in native bush, or in mixtures with eucalypts or pines. There had been little interest in pruning blackwood for form correction.
1980 trial planting.
We planted 500 blackwoods in groups of 4 trees, 8 metres between groups, and interplanted with pines. When we visited the site in the first summer the blackwoods were growing strongly, and were about chest height, but some of them were developing double leaders and competing branches. It seemed logical to trim these back, leaving a single leading shoot. Without a clear agenda, we set to with secateurs. However competing demands for time (fishing) meant we did not finish the job. In the following summer, two things were apparent: the trees we had pruned were much better in form than the unpruned trees, and the pruning had not affected their growth rate. And the blackwoods were growing faster than the pines, which were clearly having no influence on them. Over each of the following summers we continued with form pruning, directing attention to competing shoots near the top of the trees, and from about year 4 followed through with clearwood pruning from the base. When the trees were above 6 metres we thinned them to one per group.
The pines lagged behind, and made no contribution until about year 4, and by year 6 were suppressing the blackwoods. We then felled the pines. This left a thick layer of slash, which made access difficult for further silvicultural work. The pines had clearly been more trouble than they were worth.
I have a trial plot on the site, and in 2010 at age 30 the mean diameter was 55 cm. It should be close to 60 cm by 35 years, when I hope to mill them.
The message we got from this block was that on a good site, blackwoods respond well to annual form pruning, without the need for a nurse. So we decided to try something novel.
1982. Open grown planting.
In 1982 we planted blackwoods, again in groups at 7 to 8 metre spacing between groups, in the open, and undertook annual form pruning, but without a nurse species. These are probably the first blackwoods to have had this form of intensive annual treatment. Of the systems we have tried, it proved to be the simplest and most effective, and with some modifications it has been the method I have used since then.
At the same time we planted blackwoods in holes cut in an area of regenerating native scrub. This worked well, but the trees still needed an annual visit for light form pruning and remove overhanging branches. I tended to get lost when locating the trees, and spent some time wandering about in circles. This might have been avoided by cutting lines in the scrub.
1983. Blackwoods and eucalypts.
In 1983 we returned to orthodox management, and interplanted blackwoods in a mixture with with E. saligna. This worked well for the first few years, and we started to clearfell the eucalypts at about year 5. Half way through the program we encountered a problem familiar to growers who have tried this regime: we were seduced by the eucs, which were growing strongly, and looked too good to fell. So we kept them, in the hope of eventually milling both species. It didn’t work out. The blackwoods became badly suppressed, and the eucalypts thrived. Where we had thinned the eucs, the blackwoods grew well.
The message here was that nurse species provide some benefit for a limited period, but although improving form, they do not eliminate the need for form pruning. They add costs and complicate the management, and to avoid suppression have to be sacrificed on time.
In subsequent planting in the Waikato I have relied on form pruning on open-grown trees, planted in groups of 3 or 4 at final spacing. This has worked well, and has done so on other plantations in NZ that I have looked at, provided one essential condition is met: to grow blackwoods in the open and without a nurse you must have a good site, one that will encourage rapid growth. This means warmth, shelter, adequate moisture, and decent soils. On sites that are cold, dry or exposed, it is very difficult to control form in open grown trees. In those conditions you might get away with it by using a nurse crop. Or it might be better to simply plant another species.
Photos are from the Northland planting, taken in April 2010. The top photo is from the 1980 planting. The scrub is natural regeneration. The tree marked 7 (below) is from the 1982 planting, open planted and annually form pruned DBH 70 cm at age 28. Naturally it is one of the bigger trees.
Thanks Ian for a great contribution. I hope it generates some discussion amongst readers.
More concerns for the public blackwood resource
Here’s an extract from an email I recently received from another forest industry employee.
My guess is that Forestry Tasmania will cease to exist within a few years. I ……… know something of the [public] resource that is left in the North West and it’s not much. Available mature [eucalypt] resource has been largely logged and most of what is left is either not economic or has been locked up. High quality [eucalypt] regrowth sawlog resource has mostly been logged. What FT has available is mostly younger regrowth that is too young for sawlog, most of which is earmarked for Ta Ann. The blackwood resource is limited and I suspect has 5 years left at current harvest rates.
That’s 5 years of public blackwood sawlog resource remaining to be harvested before it’s all over. This certainly correlates with my own expectations of the available public resource.
The end of the blackwood industry as we know it.
AFS and FSC Certification will count for nothing under the current scenario.
As part of the Tasmanian Forestry Agreement Forestry Tasmania is currently undertaking a special timbers resource review which is due for release later this year. It is not known whether this review will include blackwood. Given the increasing uncertainty about the public blackwood resource, the resource review report will have to be very convincing in its detail and analysis. The last blackwood resource review in 1999 was anything but convincing and detailed. The fact that Forestry Tasmania has been harvesting blackwood well above the sustainable yield since the last review is just one of many points of concern.
As I’ve said before the transparent process of regularly planning, executing, managing, reviewing and reporting the sustainable blackwood sawlog production from public native forest is clearly not up to scratch, and is certainly not worthy of FSC certification.
The growing uncertainty about the sustainability of the Tasmania’s blackwood industry is cause for concern. But questions about the sustainability of the resource may be over-shadowed by more immediate issues such as the State election in March, and now the dire state of the State Government budget. Post-election the new incoming Government will have no option but to make major cuts to Government spending. Schools and hospitals will be obvious targets. But there will be no more hand-outs for the forest industry. Non-performing assets like Forestry Tasmania will be told in no uncertain terms to ship-up or shape-out. Forestry Tasmania may be forced to abandon its “non-profit, non-commercial” special timbers activities even before the resource review is finished!
It’s going to be another very hard year for the forest industry.
The only future for the blackwood industry is to focus on private growers. There is a small existing resource that can be utilised, but the focus must turn to rebuilding the resource base on private land with a dedicated growers cooperative. Engage private land owners to learn to manage and grow more blackwood. A key part of this strategy must be greater market and price transparency.
The only other option is that we all disappear into the dusty pages of history, and let the New Zealand farmers take our blackwood heritage and industry.
PS. Meanwhile the forest industry in New Zealand just keeps going from strength to strength – absolutely unstoppable!
http://www.scoop.co.nz/stories/BU1402/S00316/stars-align-for-nz-foresters-as-wall-of-wood-comes-on.htm
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