Carrabin plantation update 2013

On my way back from the north west I called in on Giles Carrabin at Paradise to see how his plantation is going. I last reported on this plantation in March 2012:

This plantation is one of the few successfully managed blackwood plantations that I know of in Tasmania and is a real testament to the effort and dedication of it’s owner. It demonstrates a number of unique features including the successful use of shelter in a windy site. Three goats now help keep the weeds and blackberries under control (see the pictures).

The regime is not one I would recommend but full credit to Giles for making it work.

A start has now been made on thinning this plantation down to the final 30 trees (it’s only a small plantation). Already the retained trees are responding to the thinning with obvious crown growth. At least another 100 trees should be thinned from this plantation this season. With plenty of spring rainfall this will be a good growing season.

While a great success this plantation still faces two major management risks:

  • Thinning too slowly so that productive green crown is lost. Already some trees are beginning to lose their lower green crown due to increasing competition between the trees. These trees are losing their productive capacity, perhaps permanently. Thinning is critical to keep this plantation fully productive and allow the blackwood crowns to develop a stable wide structure.
  • Under thinning resulting in too many small trees that are slower growing. This is a common problem with farm plantations and Giles said he is already finding it hard. Having devoted so much physical and emotional effort to get the plantation to this stage it can be a real challenge to then have to cut down the results of so much effort. This is one reason I recommend a much simpler regime.

Having watched the Blackwood in New Zealand video, the risks of thinning too slowly and underthinning are very real. Poorly formed crowns (with the risk of future crown collapse), and permanent loss of growth potential are a high price to pay after so much effort. As farmer Ian Brown says on the video, beware of becoming too emotionally attached to your trees.

With continued good management this plantation will look fantastic in five years time and be a real inspiration to other Tasmanian farmers.

Giles is now planning to establish another plantation using a similar regime but with a wider (3x3m) planting spacing. With such a labour intensive regime I can only support this move to a lower planting rate.

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8 responses to “Carrabin plantation update 2013

  1. G’day Giles, download Private Forests Tasmania’s series on blackwood and give serious consideration to the group planting regime with a low stocking of sacrificial nurse crop trees. You will get a far better result than a 3x3m planting of pure blackwood.

    • Group planting is a good option. It makes thinning a lot easier. But I certainly don’t support the use of any nurse crop. On a good site blackwood doesn’t need any nurse crop, just regular annual pruning. The New Zealand farmers have well and truly proven that. And Giles has shown the benefits of shelter from wind.

  2. Do a trial, plant some with a nurse crop and some without. I’d put money on the better blackwood developing when grown with a nurse crop.

    • Watch the New Zealand video ( They aren’t talking about more trials with nurse crops. The video clearly shows good blackwood development without nurse crops and greater complexity/cost. In fact the focus now needs to be on simplifying the NZ regime even further if possible to reduce up-front costs, reduce complexity and work load and hence improve profitability. For example is a 3:1 selection ratio really necessary to get good form? Would a 2:1 selection ratio give as good results or close too? Everything is a tradeoff. Once the Kiwis establish markets in the next few years they will also then be focusing on selection and breeding.

  3. I’ve have seen the video, been to the NZ trials in the video and met with / discussed blackwood silviculture with most of those in the video. NZ research trials didn’t utilise nurse crops, hence there are no direct examples showing / exploring the difference between blackwood grown with and without nurse crops. One site I inspected in NZ (it’s in the video) was grown with a nurse crop of eucs. This was the only example of blackwood I observed in NZ where a sawlog could realistically be expected from the second log (above the pruned but log). Trees grown without a nurse crop and thinned to final stocking (200 sph) by age 10 are too heavily branched to produce a sawlog above the pruned butt log, particularly on windy sites. The extra cost of a nurse crop may be offset by improved returns at the end of the rotation, plus the benefits of a nurse crop to reduced branching, improved form and reduced pruning requirements. There is nothing particularly complex about planting with a nurse crop, just a little extra management.

    As for selection ration, at least 3:1 is required. All those in the video had a ratio of 3 or 4:1. Tree selection must also consider tree vigour, health and crown structure as well as form. A ratio of less than 3:1 will be insufficient in most instances.

    Gordon, you’ve seen Claude Road. The blackwood there have better form than the NZ trial sites and sawlog potential above the pruned but logs while growing on a harsh site. Without the use of a nurse crop of eucs on this site the blackwood would have been poor.

    • The Kiwis aren’t talking about a second log either. 90% of the value is in the first log. Who cares about a second log?

      And Claude Road is not a blackwood site. Too dry and too exposed. Yes the trees have great form, but they are still a long way from complete management (the nurse crop is still there), and a very long way from the marketplace.

      Keep it simple. That’s the way to success.

  4. Are you using the nurse crop as a lightwell or as a windbreak, Stu? In either case, if you have a site where it’s in a sheltered gully wouldn’t that remove the need for a nurse crop?

  5. I’m well aware Claude Road isn’t a blackwood site, I didn’t select it, just did the blackwood pruning and thinning of the nurse crop. Few hours with a chainsaw and the nurse crop is gone – should have been done some 2 years ago but management is no longer my call. Personally, I do care about a second log if it can be done for little extra input. Funny that you say the Kiwis don’t care about a second log yet do include stumpage from unpruned logs in their economic calculations.

    David, what I’m suggesting is a planting with a low density of nurse crop trees (200 sph) such that they act as light wells and shelter. It’s very simple and not at all complicated once you have been shown. All but the most sheltered sites will benefit, even gullies.

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