Farm Forestry New Zealand

Pining in the sandhills

Gwen and Chris Bossley, New Zealand Tree Grower November 2008.

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In 1981, after a lot of searching and advice, we settled on a sand block in Ohau south of Levin. The 33.5 hectares had been grazed by steers and horses. There were three paddocks, some was raw sand valued at $200 a hectare, some stabilised dunes at $600 a hectare, and some peaty flats. The annual rainfall was 800 to 900 mm, with occasional frosts. We had a great view of Kapiti to the south west, as well as a lot of bracken and lupin tall enough to walk under.

Wind-blown sand on the western boundary was a problem and it was estimated that it was advancing about 10 metres a year. The sand hills, Foxton hill soils, were of low fertility, while the flats were more fertile Omanuka peaty loam. There had been extensive wetlands until the 1950s, but drainage had changed that. Our highest point, Tiro Tiro Whetu, 60 metres above sea level, has the trig station.

The area was roamed by Te Rauparaha and there is still a large sea shell midden just over our boundary. The Cobb and Co coach from Wellington to Foxton crossed the adjacent Ohau River.

We arranged a grazing lease and started clearing the bracken and lupin with grubbers. We were visited and advised by forestry extension officer Tom Muir. Full of enthusiasm, we planted 2,000 elite pines at 3.5 cents each and 200 macrocarpa from Maurice Murray in Woodville. We watched dismayed as the majority failed, due to rabbits, drought, wind-blown sand and overgrowth of bracken and lupin.

Learning

We applied for and were awarded a Forestry Encouragement Grant. Gavin McKenzie encouraged attendance at the NZ Forest Service Flock House course. Never has so much knowledge been presented and assimilated in such a short time. Theory was followed by practice, with visits to Denis Hocking’s farm and Lismore Forest. Accommodation and food was superb, while spirits or a jug of beer in the evening set us back 50 cents.

Armed with this knowledge, we helicopter-sprayed the lupins with excellent results. At last we could see where the planting rows were supposed to be. Spot spraying made planting easier. We did have problems with Velpar on the sandy soil, as although it gave an excellent bracken and lupin kill, the pines did not survive in the pre-sprayed spots.

Planting the pines

Over the next few years the family and some friends planted about 6,000 pines a year. Under grant regulations we had to plant 1,000 trees per acre. We thought this was excessive and after the first year went for wider spacing. As an experiment one year we tried planting blackwood, Acacia melanoxylon or Eucalyptus botryoides in every third space.

This was not successful for various reasons, including wind, beetle infestation and different growth rates. It then struck us that planting was easy, releasing a little harder but the main problem was silviculture. The first plantings were due for pruning lifts before we had finished our planting programme. We were weekend foresters and professional help was needed on two occasions as we fell behind.

Thinning and pruning

Our policy was to prune and then thin all unpruned trees. Many of these thinnings were donated to clubs for fund raising as Christmas trees. We also borrowed a tyre-driven peeler and took trees out for posts, which we used to sub-divide the rest of the farm. Cattle were allowed in for short periods from the fourth year with reasonable grazing under the trees until year 10.

We had a visit from Neill Barr and Harry Bunn on one Middle District field day. They were both amazing, with their energy and enthusiasm, racing up and down the sand hills. They demonstrated form pruning with general advice. One block was a mixture of pines and gums. Neill and Harry had a long discussion about which species should be retained, taking opposite sides. They both wrote thank you letters afterwards, and each admitted they were wrong and said they thought the other had the correct option. As a compromise, in this block we have retained the best specimens of both species.

After Tom Muir’s death, Blair Haggitt was our mentor for many years.

Advice

We are members of both Middle Districts and Wellington farm forestry groups, so field days have provided much interesting discussion and debate. One example was a group of macrocarpa, pruned to three or four metres, badly affected by canker. Several trees had died and the advice ranged from clear felling, through thinning of affected trees, to doing nothing. We did not prune any more but the disease is not present now and there are some good butts in the remaining trees.

The pines are growing well, now 22 to 26 years old and increasing in diameter 1.5 to 2 cm a year. Pruned in four lifts to 6.5 metres, most are about 340 stems per hectare. In some areas we were not radical enough in our thinning − you should have someone else fell the trees you have tended.

We had some wind damage last year but very little in the recent storm. Pines do not blow over in the sand due to their long tap root, but they can snap off. The experiment has been great fun, keeps us fit and has gained us many friends. Throughout, we have had great advice from NZFFA members, individually and at field days. Whether our forest will be financially worthwhile remains to be seen but we are optimistic that common sense will soon prevail and wood will be valued for the resource it is.

See: Pining in the sand hills, Episode two. New Zealand Tree Grower May 2013.