On Feb 18, 2011, David Hewson of ECan led a small group up to Flock Hill to discuss wilding control operations for the present year.  Present with Dave were Ray and Marie Goldring of the upper Waimakariri Environmental and Landscape Restoration Alliance (WELRA – main current focus is wilding removal), Dean Turner of DOC, Darrin Woods (wilding expert) and Nick Ledgard (NZWCMG manager).  First we looked at the results of past aerial spraying operations (see photo).  Most of these were using ‘brews’ prescribed by Andy McCord (of Andy McCord Technical Forest Services Ltd) which has diquat as the major contact herbicide plus a cocktail of additives.  It is pleasing to report that these contact herbicide brews are currently being trialled alongside the DoC brews containing systemic herbicides such as glyphosate, metsulfuron and triclopyr, so by this time next year we will have a good idea of the most cost-effective ‘best bet’ herbicides for aerial spraying of a range of wilding conifer species.  In the near future, there will be an update on this trial series.

Dean Turner of DOC inspecting contorta wildings aerially sprayed with a contact herbicide mix a year ago.  New trials are underway, comparing both contact and systemic herbicides, so the  most cost-effective, ‘best-bet’ sprays should be known by next year.

WELRA has been diligently seeking funds for a few years now and current funding for the 2010/11 year totals over $100k and originates from the Pacific Development and Conservation Fund, Flock Hill station, Environment Canterbury and DOC.  Plus, wilding control days are always well attended by volunteers, who have been the main removal agent for distant outlier trees. 

From SH73, which passes between the Craigieburn range and Flock Hill station, the view to the east can look depressing to passers-by, as the wildings continue to become more widespread and dense.  However, what most people never see is the large areas further back from the road which have been cleared of wildings; these mainly involve high altitude, exposed ‘take-off’ slopes and ridges plus  hundreds of hectares of widely scattered conifers at lower altitude.  The primary aim of the control plan written for Flock Hill (by Darrin Woods) in 2007, is to arrest the invasion of new land and to bring the affected land back to a core area, which can be treated by aerial spraying once the most appropriate herbicides have been determined.  In the meantime, it is inevitable that these core areas will continue to thicken up – and unfortunately, these are the most obvious areas to the passing public.

In the near future, WELRA will be erecting a sign alongside the highway near the entrance to Broken River ski field, which will explain the wilding control process, what has been achieved to date and what is planned for the near future.


A DoC, ECan, WELRA team discusses 2011 control priorities for contorta pine wildings spreading on the southern  flanks of Constitution Hill, Flock Hill station.  In the background is the Craigieburn Range, from which the spread originated.