Wood Matters

The spread of wilding pines from farm shelter belts and forestry plantings into tussock and less intensively grazed introduced grasses and native scrub vegetation has become a major issue throughout parts of the central North Island and across the South Island. Pinus contorta, P. sylvestris, P. mugo, P. ponderosa, and P. nigra along with larch and Douglas fir are the main species involved in the invasion.

The majority of the problems stem from legacy plantings of these species by early run holders and government agencies. Whilst the pine species are no longer planted for commercial use Douglas fir remains an important commercial species in the South Island. The spread of regeneration from these species into neighbouring land has resulted in community concerns in many areas and significant costs are being incurred by forest and land owners in controlling the regeneration and preventing further spread.

In many areas this concern has resulted in controls being placed on forest owners and their ability to plant Douglas fir, threatening the “licence to operate” for forest owners large and small.

The New Zealand Wilding Conifer Management Strategy 2015 – 2030 aims to prevent the spread of wilding conifers and contain or eradicate established areas by 2030. This strategy has been adopted by Government with the support of land owners, forest owners, and local government. Central government funding has been allocated to assist with a coordinated programme for control and prevention of spread.

These efforts have been further supported by the approval of a 5 year research programme funded by MBIE, local authorities and forest owners. While led by Landcare Research the programme is a partnership with Scion, Canterbury University and Lincoln University with a number of themes covering dispersal, ecological impacts, legacies, detection, control, prevention, and improved overall decision making or prioritisation.

Whilst forest growers are interested in the wider programme, their area of most interest is in finding a solution to enable the planting of Douglas fir for commercial timber production to continue. This research is focused in the shorter term on identifying trees that produce less seed and reducing the seeding and spread of regeneration through inducing cone abortion in mature trees. In the longer term, it is focused on utilising newer biotechnologies, including gene editing, with the aim of developing sterile trees. If this can be achieved it will overcome a major barrier to further planting of Douglas fir in the cooler parts of the country where it is best suited. The growers also have an interest in early identification of wilding regeneration through remote sensing, and more cost effective control regimes. Whilst much of the problem stems from legacy plantings, forest owners accept their responsibility for helping to find solutions and are contributing to the research effort via the Forest Growers Levy Trust funding.