If you could travel back in time to about 1400AD you would find the mountains surrounding Wanaka, and for that matter most of Central Otago, were covered with totara up to 1200m above sea level.
Tussock grew only above this elevation, with the exception of some rocky escarpments and tight ravines.
Thus, totara not tussocks were what biologists call the "climax species'' for these slopes.
In other words, if you started off with bare land, given enough time totara would eventually prevail.
Unfortunately, by 1500AD a large portion of these forests had been burnt off by Maori to facilitate their hunting of moa.
Later the Europeans pretty well finished off what was left of the totara in the development of hill-country farming.
In the meantime the settlers brought into this environment many invasive species which have subsequently become a problem: rodents, rabbits, broom, gorse, briar, hawthorn, wilding pine species and hieracium.
Today, farmers are struggling to control these pests and to keep the slopes in pasture.
Even in the higher cleaner areas such as the Lindis Pass and Crown Range, tussock is being squeezed out by hieracium.
The best weapon we have in the battle against the wilding "weeds'' is to bow to the knowledge that trees, not tussock, are the natural "climax species'' in these areas.
While this used to be totara, it is likely now that if the land was left for long enough we would mainly get wilding pines inheriting these slopes.
Once you recognise the biological inevitability that wilding pines are the most likely species to take over our slopes, then it is essential to develop a smarter and more pragmatic solution to the problem.
Indeed rather than be part of the problem, some species of "wilding pines'' could become part of the solution.
There are 10 main species of so called "wilding pines'' but the four really common ones in Central Otago are Pinus radiata, Pinus contorta, Douglas fir and Larix deciduaa (deciduous larch).
I personally don't like the weedier radiata and contorta and am quite happy to see their spread discouraged.
What I would like to debate is whether the Douglas firs and larches should be lumped into the same category.
Douglas firs can grow to more than 30m tall.
They have real value in their timber, while larches are also excellent timber but additionally give a beautiful golden yellow colour to autumn.
Together the two species are a good mix.
If trees are going to be the climax species on our slopes and totara, in most cases, is either too expensive or too impractical to replant, would we not be better to remove the "weedy wildings" (radiata and contorta), but leave and even encourage Douglas fir/larch plantations?
As an adjunct to this, effort could be put into protecting kanuka stands in the hope that totara will eventually come through this intermediary as a successional species .
Limited financial resources could be targeted on protective "no grow'' zones around larger stands of native forest.
I would like to understand what long-term goal the Queenstown Lakes District Council (QLDC) hoped to achieve by spending a large amount of ratepayers' money spraying out the large stands of fir/larches in the Queenstown basin, leaving a legacy of dead trees and an providing an environment for the other "weedy wildings'' to thrive.
The council has quoted "environmental reasons'' for not having these trees.
What about the compelling reasons why trees are good for the environment ?
1. Forests absorb CO2 and of course this helps mitigate global warming.
2. Trees help reduce soil erosion, in a country which has one of the largest soil loss rates in the world.
3. Trees absorb nutrients such as phosphates and nitrates from the water table, thereby helping to clean up the groundwater before it moves into our rivers and lakes. We need this filtration to help address the increasingly serious problem with eutrophication in our lakes and the dramatic increase in algae growth.
4. More trees, fewer rabbits.
5. The Otago Regional Council and the QLDC are on record as claiming that trees reduce water yields in already dry catchments, but from what I understand this statement is simply incorrect.
Have they taken into account the drying effect of wind on our treeless slopes ?
What about transpiration?
According to the Max Plank Institute of Meteorology, mature forests in temperate regions increase rainfall by 10%-15% compared to pasture.
In my view, public bodies are both wasting scarce resources and ultimately harming the environment through the destruction of some potentially beneficial tree species.
Clearly, their position is different to mine, but is it based on science?
I have yet to be convinced that a robust scientific basis can be shown which warrants vast swathes of unsightly dead trees which will be an eyesore in the landscape for decades to come.
● Wanaka man Peter Whiting is a retired geologist and businessman and a former All Black.
