Farm Forestry New ZealandWay down south at Whataroa
John Spencer, New Zealand Tree Grower May 2010.
John Spencer of South Westland has been a long term member of the Westland branch. He undertakes traditional farming at his property near Whataroa. It is a high rainfall area less favoured for radiata pine. John is passionate about his trees, and won the Peter Smail Shelter Award at the 1994 West Coast National Conference.
After leaving the Southern Alps the Whataroa Valley opens out on to a wide coastal plain with gravels, sand and silt being deposited due to the reduced river speed. These materials have weathered to form relatively fertile alluvial soils, although drainage can be poor through the finer silts. As on all other West Coast river plains the forest was gradually cleared.
Farm development was still being undertaken by the Department of Lands and Survey in the 1970s and 1980s, with an emphasis on dairying wherever possible. My farm covers 74 hectares of productive land on which I milk 120 to 125 cows. Calves are reared on the farm but heifers are grazed off the property.
The soils here have not been intensively mapped but the 1965 soil map of the South Island shows this farm to be on gley alluvial Harihari soils. The gleying is caused by inadequate drainage either due to localised hollows or heavy silt textures. Phosphate and sulphur levels are low as are potash and calcium. Magnesium and selenium are marginal. Annual applications of superphosphate and lime are needed.
Rainfall is about 4,000 mm a year with frosts as low as minus seven degrees. Soils vary from being light and gravelly to silt up to 60 cm deep. Intensive drainage has helped raise productivity, but the ground may still become waterlogged after prolonged periods of rain.
Shelterbelt establishment
I have lived on my farm in Whataroa for almost 32 years and planting of shelterbelts started in the winter of 1979. The initial shelterbelt was of two rows − radiata pine and Douglas fir. At first the growth and health of the trees was disappointing, with dothistroma needle blight evident in the radiata from an early age. Even on the light shingly soil some trees failed, where water flowed after heavy rain. After considerable thought these gaps were filled with black alder which was a spectacular success.
The pines were sprayed twice at ages four and seven with a copper-based fungicide to control dothistroma using a gorse gun. The trees are now vigorous and healthy. A number of radiata have been blown over in south easterly winds and the gaps planted in a variety of trees including copper beech, English oak and dawn redwood. The radiata are now pruned to approximately six metres.
Trees have been planted every year since 1979. In 1980 I planted a couple of rows of western red cedar with the eucalypts Eucalyptus nitens, E. maidenii and E. ovata. One row lost 70 per cent of seedlings many to pulling by pukekos – something I had not anticipated. Growth of the E. nitens has been spectacular and they are pruned to six metres. Initial growth of E. maidenii was good, but after five or six years slowed appreciably.
Cedar for huhu grubs
Western red cedar has grown with vigour and is this respect was clearly superior to other conifers in South Westland. Unfortunately some live ones recently cut down were found to be infested with huhu grubs, consuming most of the heartwood, leaving only the sapwood to hold the tree against the wind. Although this has been found in other parts of New Zealand, I have been told that it was not a problem in the original Forest Service stands in Central Westland.
In 1981 and 1982 double rows of western red cedar and Scots pine were planted. They are healthy but slow growing – it looks like being 50 years before the pines will be large enough to mill.
I have always had a great love of deciduous trees, and over the last 20 years only deciduous trees have been planted on the farm, mostly in single row shelter belts, with others in gaps in the conifer belts. The oldest deciduous trees are ash at 28 years, and a row of liquidambar now 26 years old on the back boundary. This colours beautifully but has been damaged periodically with wind.
No pattern
Hares have caused damage to ash species, ring-barking trees up to three years old. There seems no pattern to their damage – some rows are untouched, others severely damaged. Fortunately most ash species coppice readily.
A diverse range of deciduous trees has been planted. One row on the boundary contains, amongst others, ash, elm, alders, limes, oaks, japonica, sycamore and dawn redwood. Pruning has begun on ash, elm, sycamore and oak. The interplanting of ash with alders looks particularly promising.
On a clear day a magnificent view of the Southern Alps is available from the farm. I find this New Zealand’s most beautiful province. Our current development enhances rather than detracts from this great natural environment.
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