Scientific name: Pinus nigra

Common name: Corsican pine

Corsican pine (Pinus nigra) is a hardy species with a well recognised potential for timber and roundwood production. It is a relatively common species in the high country where it has proven hardier than radiata pine (greater browse resistance, and more tolerant of unseasonal frosts and wet snows), and better suited to drier sites and flat frosty sites than Douglas-fir. For these reasons it is likely to continue to feature in high country forestry.

Origin

The species occurs naturally through most of the northern Mediterranean seaboard from southern Spain to Turkey. It is most frequently encountered in the mountain areas.

At least five subspecies are recognised in its home range but only two are commonly encountered in New Zealand. The true Corsican pine (P. nigra ssp. laricio) originates from Corsica, Sicily, and southern Italy. It has the more regular, conical form and is the only commercially acceptable form in New Zealand.

Austrian pine (P. nigra ssp. nigra) is more bushy with heavy, wide, spreading branches and is prone to forking. From a forestry point of view it is not as desirable a tree.

Description (the next para was omitted from your text)

Corsican pine is most readily recognised by its foliage, winter buds and tree habit or form. The needles occur in pairs while the winter buds are ovoid to cylindrical, covered in small white scales and ending abruptly in a tapered point. Tree form is characteristically conical with an orderly slender crown of sparse, short. light, horizontal branches. In the high country the species is most readily confused with Scots pine and lodgepole pine both of which have needles in pairs.

History in New Zealand

Corsican pine was first introduced into New Zealand about 1866. Large plantings were made between 1920 and 1930. By 1970 the species ranked third by area in exotic forests behind radiata pine and Douglas-fir. Plantings declined rapidly after 1964 when the pine needle blight, Dothistroma pini, invaded New Zealand. In the warmer, moister parts of New Zealand, Corsican pine is very susceptible to attack irrespective of age. The pine needle blight is not a problem in the high country.

In 1985 there was approximately 16 000 ha of Corsican pine (9000 and 7000 ha) in the North and South Islands, respectively). In the central South Island high country Hanmer and Naseby forests used to have a high percentage of Corsican pine. Most has now been replaced by radiata although Naseby plantations still total around 1000 ha. The largest areas of Corsican pine consist of natural regeneration or wildings. There are hundreds of hectares around Naseby and over 6000 ha around Hanmer where wildings are present.

Siting

Corsican pine is a very reliable species on cold and exposed sites where radiata pine is at risk. It is the most site-tolerant conifer of use in the high country with commercial possibilities up to at least 800 m above sea level. Not only is it tolerant of a wide range of soils, but it also withstands snow well and will survive weed competition and animal grazing more readily than other conifers. It can also tolerate drought prone sites, although growth rates are slowed considerably and wood qualities may be poorer. Despite this, it is usually the best commercial choice for high altitude, flat,dry sites

Growth

Average growth rates are only 50–60% those of radiata pine and 85–90% those of Ponderosa pine. However, Corsican pine can attain large dimensions in old age — 35 m tall with a diameter at breast height (word omitted) of 100 cm after 100 years. After 20 years on a good, moist site an open-grown Corsican pine tree can be 15 m in height with a diameter of 30 cm. In plantations, the species has the advantage over radiata of being able to sustain good growth rates and higher stockings over longer periods of time. This is particularly apparent at higher elevations. (sentence omitted) Rainfall is the greatest determinant of growth potential. The figure below graphs the potential productivity of fully stocked stands relative to rainfall at age 50 in the Canterbury high country.

[Figure - Potential productivity relative to rainfall]

Establishment

Corsican pine can be grown for sawlogs or roundwood (posts and poles). Roundwood regimes use denser stockings to keep branch size down and to reduce taper.

The minimum initial stockings for high country sites suggested below may need adjustment (higher or lower) for specific site conditions.

Spacing and stocking relative to rainfall (revised table)

Recommended seed sources

All seed should originate from registered seed sources representing the best genetic quality available. Registered stands are located at Rankleburn Forest, Southland (Compartment 37); Balmoral Forest, Canterbury (Cpt 57); and in Golden Downs.

Silviculture

The characteristics of light and uni-nodal branching and conical crown form make Corsican pine a silviculturally adaptable species. Combine this characteristic with the ability to carry high stockings without significant mortality, and there is the opportunity for production thinnings for post and pole material (on more readily accessible sites only), or for regimes aimed solely at roundwood production. The extensive nature of land uses in the high country mean that the minimum tending regimes involving no pruning and zero or light thinnings (roundwood) to medium density thinnings (sawlogs), are likely to be the most desirable. The shorter rotations and increasing scarcity of Corsican pine posts and poles (often favoured ahead of radiata) have heightened interest in the roundwood option.

Corsican pine also lends itself well to agroforestry regimes ( the most common design is double rows spaced 20 m apart), and shelterbelts, where its short branching habit means that side trimming to keep branches inside fence lines is less frequently needed than with radiata pine and Douglas-fir.

The table below gives sawlog, roundwood and agroforestry regimes for the high country.

Fortunately, the climate in the South Island's high country does not favour Dothistroma pini so that the area has a unique potential to grow Corsican pine. Apart from Dothistroma needle blight, the only other pathogen sometimes encountered is Diplodea pinea. This can cause pronounced branch tip dieback in severe drought years, although the species is not as susceptible as Ponderosa pine.

Stunted growth or leader dieback is a common symptom of boron deficiency. Boron is usually applied 3-4 years after planting at the rate of 0.5 g to 0.7 g elemental B per seedling.

Uses

Corsican pine is grouped with radiata pine as a general utility timber. Nationally it is described as having a slightly denser and harder timber, but samples taken from high country trees have been similar to radiata, averaging around 390–400 kg/m3.

As a pulp wood it is regarded as somewhat inferior to radiata because of its higher resin content.

The species has very desirable attributes as a roundwood timber. Branches are smaller than radiata pine with less nodal swelling and growth rings are tighter, resulting in stronger posts and poles. In addition, its ability to hold more trees/ha relative to age can be used to advantage to produce a high yield of lightly branched, cylindrical stems with little taper.

There is a steady local, and unexplored international, demand for roundwood (particularly poles) which has led some commentators to suggest that the high country could specialise in growing quality Corsican pine roundwood. This potential certainly deserves further investigation. Current research is looking closer at wood quality characteristics and silvicultural regimes best suited to producing posts and poles.

Natural regeneration

In Canterbury, wildings of Corsican pine affect more land than any other introduced conifer. The species has light seed (50 000/kg) which are readily wind spread, and young seedlings are very unpalatable. The risk of spread should be considered in the planning of all plantings (See Section on wilding spread).