duane wrote:Ghosta in reply to your query
you havent explained what changed to make certain willows a problem.
Try this:
It is invasive.
It spreads too quickly
It's residue fails to break down.
Its a monoculture.
It's killing ALL of our catchments.
It prevents biodiversity from growing beneath it.
It takes more water out of our waterway systems than native plants
And the landscape condition has deteriorated SO much that the area and the job willows have to cover has increasingly got bigger.
All reasons for putting it on the WONS list.
Well some of the reasons you have given are correct. But its not "It's killing ALL of our catchments." And the statement " the landscape condition has deteriorated SO much that the area and the job willows have to cover has increasingly got bigger" is certainly questionable given that other plants can and will be doing this job in future.
The thing that HAS changed is the widespread use of hybrid willows from the 1980s on.
from
http://www.aabr.org.au/index.php?option ... &Itemid=74
"Generally, willow seed is very small, very short-lived (2-4 days), produced in massive quantities over several weeks, highly fertile, capable of dispersal over very large distances by wind, and very specific about the characteristics of a suitable seed bed. This means that usually most seeds do not survive but, when conditions are suitable, hundreds of thousands of seedlings can establish.
As willow seed is very short-lived, all of the early introductions of willows were made as cuttings or pot plants. This meant that most of the plants of any species, or at least the plantings at any one site, were derived from one or very few individuals. As willows are mostly either male or female this has meant that most of the clones were unisexual and plantings rarely produced seed or seedlings. Seed was only possible from hybridisation of two different species where the correct sexes were present; the flowering times overlapped; and the trees were closer than about 3-500 metres, (about the maximum effective distance for the pollinating insects.) The sparcity of plantings, other than massed single-clone plantings, and the lack of overlap of flowering times for the different species has meant that seeds were hardly ever formed.
Over the years more species and cultivars have been introduced. Some of these cultivars were hybrids between other species, often very rare. If such hybrids are planted, and either or both parent species are around, they can overcome the problems of non-overlapping flowering times, and also reduce the inter-species fertility barriers. There is now an increased opportunity for fertile and viable seed to be formed. As trees aged, the longer they tended to flower and the more likely that overlaps occurred. All such situations have occurred and there are now areas where there has been mass colonisation by seedling willows. Although these are, so far, usually serious to the 1ocal area only Salix cinerea, (a Pussy Willow), has proven to be a serious problem over large areas to date. It is a serious problem in Victoria, becoming a problem in southern N.S.W., but we now also have a population producing seeds around Sydney."
The dilema for followers of NSF is that willows can be used sucessfully to achieve the aims of the landowner, often with no effect that is seen as detrimental to him/her. The fact that willows dont provide much habitat for native species may be completely irrelevent, as an example.
Willow spread may be completely under control at present due to the lack of suitable cross pollinating stock. But there is certainly no guarentee that it will remain this way, all it would take is for a neighbour to plant a willow of a differnt sex or variety which allows cross pollination and the
someone is likely to have a problem...it may or may not be you.
Governmet authorities have chosen to act to minimise the chances of this happening and to fix existing problems.
Fortunately there are other species of plant that can do the job that willows can do- perhaps not as easily, but taking "problem" willows out of the NSF toolbox does not mean the end of this approach to farming. In my view NSF advocates should not be at war with authorities, rather they should be demanding some of the funding be used to find the most suitable
alternative species for their particular situation.