Wilding Conifers – not in my backyard?
Since their introduction to New Zealand in the 1880s, conifers have significantly impacted the New Zealand landscape. Along with providing high-quality and fast-growing trees for our timber industry, conifers have also played a vital role as shelter belts for our agricultural and horticultural industries.
However, since the 1970’s New Zealand has been dealing with the burgeoning issue of the spread of ‘Wilding Conifers” which has resulted from self-seeded conifers becoming established in places they are not meant to be. Unlike commercial forests, wilding conifers are weeds. Wilding conifers are the plants that pose the biggest threat to New Zealand’s unique environment. They are as much of a menace to our environment as stoats, rats, and possums. A report in 2011 concluded that wilding conifers were spreading by 5% a year and left unchecked these ‘tree weeds’ would cover 20% of New Zealand's land area by 2030.
Wilding conifers on Mt Isobel, without control this landscape will become a forest in the next decade with native species disappearing due to being shaded out.
The lower slopes had been burnt and grazed years ago and the regenerating vegetation consisted of kanuka and coprosma, and in some areas, the broom was very thick and difficult to negotiate.
Well-established conifers were dotted through these areas. Access to these trees was a slow and scratchy affair, sometimes the easiest route was crawling through tunnels beneath the vegetation made by the local pig population. Once the target trees were located they were either cut down and stumps treated with cut-n-paste picloram gel or ring barked. When cutting trees down, care must be taken to ensure no branches or green needles are left on the stump for the tree to regrow from.
Searching for young wildings amongst the native sub-alpine vegetation.
Removing these trees from this environment is vital to prevent further spread. A single tree can produce over 20,000 seeds a year which can remain viable in the soil for years. The conifers are capable of growing fast and tall and will completely shade out native species and dramatically change the ecosystem.
On the higher slopes, the team contoured around the slopes to ensure all the ground was covered. Binoculars are an important tool in this work, to correctly identify the species for committing to the sometimes long walk or climb to get to the tree. It was extremely rewarding to find and remove the conifers from this fragile and unique environment and we took heart that this work will help preserve the iconic high country landscapes in their natural state. But we must refrain from turning our backs on wildings as the cost and difficulty of removing them rises exponentially each year as the trees disperse more and more seed on the wind and grow in size.
A pair of loppers and cut-n-paste - essential tools for eradicating trees in their juvenile stage
In June of 2022, we returned to the site with a chainsaw crew and were able to remove some of the larger trees left the previous year. We hope to go back again to this site as funding allows.
If you have a wilding problem in your backyard, be sure to tackle it earlier before it turns into a much bigger problem.
