Douglas fir – the next wave of wildings -Reporting the recent spread of wilding Douglas fir in the southern South Island
Date: 10th April 2025
This is an opinion piece by Richard Bowman, past chair of the Wilding Pine Network.
There is a new wave of wilding conifer spread that is now starting to become widely recognized
particularly in the southern South Island. It relates to the widespread planting of Douglas fir
(Dfir) mainly for commercial forestry purposes in the early 2000s. These trees have been coning
now for up to 10 years. Given the number of new seed sources, rates of spread and proximity to
vast areas of highly vulnerable hill and high-country land, this latest generation of wildings may
dwarf the impacts of those of earlier legacy plantings from 1950s -1980s.
The first wave of legacy wildings has already cost New Zealand well in excess of $150M for control management. The next wave coming may well exceed this unless effective preventative policies and
management measures are urgently put in place. The aim of this paper is to raise awareness of this new wilding threat in order to prevent repeating the mistakes of the past. If the initial warning signs of earlier legacy wilding conifer spread had been recognized in the 1990s and prompt action taken, then we may not have required the national Wilding Conifer Control Programme we have today.
I am focusing on the emerging problems in the southern South Island where I have direct knowledge. I am aware that similar issues are present in many other parts of New Zealand but have not yet been recognized or brought to attention.
The impetus for this paper came from a quarterly meeting of the Mid Dome Wilding Trees Charitable Trust in September 2024. Here Environment Southland staff and those from the Project Manager, Boffa Miskell Limited, said they are now finding Dfir seedlings routinely during Pinus contorta control and maintenance practically everywhere they look in the programme area. These were not present a few years ago and they see this as a serious new problem arising just as the programme is starting to get wilding Pinus contorta under control.
This led to the realisation that an uncontrolled Dfir infestation on the ranges at Mid Dome has the potential to spread downwind across thousands of hectares of the Garvie Mountains and eastward to the Clutha River and beyond into Central Otago.
It also led to the realisation that there are many similar Dfir infestations starting to develop across Southland and Otago which threaten vast areas of hill and high country. These lands are under low intensity land use or protected for conservation purposes and offer no resistance to invasion by Dfir.
This paper identifies warning signs of the ‘next wave’ of wildings. This is being caused by Douglas fir (Dfir) planted in Southland and Otago from the late 1990s to the early 2000s. Failure to recognize and take early and effective action against this will nullify the efforts of the last two decades dealing with ‘first wave’ of legacy conifer plantings. From the descriptions of the sites in this paper it should be evident that there is a high risk of wilding spread risk from a number of known Dfir seed sources in Otago and
Southland.
The potential extent of spread from these plantings is illustrated in Fig.1. This shows that new Dfir seed sources are located on or close to land classed as having “very high vulnerability”. (The term is defined in the report: Methods for the prioritization of wilding conifer sites across New Zealand. Wildlands 2016). The area of this high-risk land class in the southern South Island covers almost 2 million hectares.
To read the paper in detail please find it below as well as the 2016 Wildlands Report referred to above. For further information contact Richard on richard@wildingpinenetwork.org.nz.
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