Tony Denton is a regular and long-time FWG volunteer. His bailiwick includes tackling invasive tree species that keep popping up on our grounds. You could say that he is a regular ‘hatchet man’!
How long have you been a volunteer at FWG? Why did you decide to start?
The date is vague in my mind, it was soon after I retired and looked around for activities. I came to the annual ‘Migration Day’ in spring, took the birding tour with Jeff Harrison (co-founder of the FWG and chaired the management committee for many years) and decided that I liked the area. We talked for quite a while, back at the Interpretation Centre, about gardening in difficult conditions, which we shared. He convinced me that I should build a pond.
When did you begin to tackle buckthorn – your cause célèbre?
It was not a conscious decision, it happened by default. I tried the tasks offered, did not like weeding, did some handyman stuff but after making a notice board, getting the composting working and setting up the hose system there was not much to do. The buckthorn removal was already under way in the hands of Malcolm Leith and Dale Crook (there may have been others) and joining them seemed natural.
What methods have you used to control buckthorn?
FWG owned the #2 Weedwrench which we put to good use, later completing the set. That old #2 is still bent from over-use in those days. We also used Round-Up, very carefully because its use violated the principles of FWG not using chemicals. The cut stump was painted carefully, but was not 100% successful, nor was drilling a hole in the tree, filling the hole and putting a cork in it. The trees proved to be segmented in such a way that only part of the buckthorn would die.
We also tried cutting the roots around the tree with a pruning saw, which worked until the saw lost its edge, which was not long. I later found that an axe could do the same job, and could easily be sharpened. This only worked because the roots of buckthorn grow close to the surface, with no tap root (with exceptions).
Later I tried covering the cut stump with thick pool liner, vinyl at first and later rubber which proved superior. This method is still used, usually for the larger stumps, pegging the cover down then putting earth over it to keep it lightproof around the edges.
Which methods do you find most effective? Why do you think that is?
The root crown has to be removed, having done that you know that the tree is not going to re-grow. In an area of widespread growth, a team of three people can work through clearing buckthorn quite rapidly, even quicker with more help. All infestations of this kind have been cleared at FWG, leaving isolated large buckthorn trees in places which are difficult to work in, and small areas which were overlooked. In these cases the ‘cut-and patch’ becomes the method of choice, one which can be handled alone.
Is controlling buckthorn at FWG different than in other contexts?
Every situation is different. At FWG we only work in wooded areas when birds are not nesting – early spring and late fall. At woods near my home is a small city park where we can only work two mornings every year. At the Pinney Sand Dunes all of the buckthorn are glossy, grow very slowly and are easy to pull from the sand. When they get older it is a different story.
Common Buckthorn is also much more difficult to pull in grass, very wet soil and probably other soils.
Do you feel that you and those who help you are making progress in the removal of buckthorn at FWG?
The removal is ongoing. The challenge is to maintain the effort needed to keep up the work when there is no obvious need.
What new techniques are you considering to control buckthorn, if any?
There are none that I know of. The only real solution is biological and that is a long way away. The seeds are spread by birds, in their droppings, so making sure that there are no berry-bearing buckthorn trees in the area would be the best control.
What other problem tree species are you dealing with at FWG? Do you think they will prove to be more problematic than buckthorn in the future so far as speed of spread and control?
There are other invasive trees so it is important to recognise them and act quickly. There is always a tendency to ‘wait and see’ when new species appear. The Amur Maple is an example of a tree which was thought to be invasive – but it was even recommended last year for new housing areas – and nothing was done until recently at FWG to control it.
Some invasive trees are available at local garden centres. Even buckthorn was available long after we were pulling out as fast as we could. The excuse given me once was ‘people demand them’.
Recently the European Spindle Tree (Euonymus europaeus) has appeared in at least three places at FWG and shows symptoms of being invasive.
Tatarian Honeysuckle (Lonicera tatarica) has taken over parts of Gatineau Park and we should be clearing it from FWG, if we had the manpower.
If you could ask people to learn one thing about buckthorn to help in its control, what would that be?
If people recognised buckthorn in its early stage and treated it like any other weed, pulling it out, we would not have the present infestation. Common Buckthorn only appeared in FWG about 1980, which shows how quickly such a weed can spread.
Learn more about buckthorn:
Want to help with removing invasive trees at FWG?
Tony predominantly works as part of the Friday morning group, who meet from 8:30 until 12:30. Sometimes he comes on off-hours, and is pondering a weed bee for the autumn. For more information, contact us at fletcher [at] ofnc.ca