Melbourne is famous for its English elms (Ulmus procera) and is really lucky compared to Europe and America as we still have them intact. It is one of the few places in the world you can still see avenues and stands of these magnificent trees, which were once common across the UK, Europe, and northern America but are now limited in those countries to a handful of remnant and isolated trees due to Dutch Elm Disease.
True we do get the elm leaf beetle and the elm bark beetle which spreads the Dutch Elm Disease but so far we haven’t had an outbreak of this fungal disease. Unfortunately New Zealand has, which is getting a bit too close for comfort.
I remember way back in the 1980s if you drive through Frankston (south of Melbourne and the gateway to the Mornington Peninsular) just as you approach the city centre there was a sign warning people that the ‘Elm leaf beetle hitch-hikes’. The beetle wasn’t in Melbourne back then, but it definitely is now.
According to the City of Melbourne, they manage approximately 6,000 elms, which include avenues of elms, specimens in our parks and gardens, and street trees. Most of Melbourne’s elms were planted in the middle to late 1800s. The earliest I know of is Arthur’s Elms (John Arthur was the first curator), planted in 1846 in the Royal Botanic Gardens, Melbourne. We know they came from his nursery but we don’t know where he sourced the seeds from.
Melbourne’s English Elms are aging and due to drought, poor pruning practices and other environmental stresses many of them are declining. We Melbournians love our elms, and as the City of Melbourne manages so many they have set up a trial to try and find out more about their genetic diversity and where it is located. What they don’t know is how diverse the genetic make-up is.
If they are similar, then the planners don’t need to worry about maintaining the genetic gene pool because they are basically all the same (clones) but may have to introduce new cultivars to increase the Elm’s diversity to protect against large scale population losses. If the trial reveals there is genetic diversity, then it needs to be maintained because it will help protect the elms against attack by pests and diseases and the ravages of stress in an urban environment. In this case the City of Melbourne will propagate from the existing trees and replant them into our parks and gardens.
The council has been working with the community and have organised a group of volunteers called Citizen Foresters to help identify and collect elm leaves in the Fitzroy Gardens. I went along and learnt a lot about identifying elms. Gosh, have I been walking around all this time and not noticed the differences? Yes. It was a really great morning. First, Amelia and David (one the City of Melbourne’s arborists) taught us how to distinguish the different elms features. It seems that a lot of what we think are English Elms are actually Dutch Elms, that is Ulmus x hollandica.
English elms have a denser, darker crown, the leaves are smaller, rough and rounded, and it has darker bark and deeper fissures. Usually, there not more than 12 veins in the leaf.
Dutch Elms have a more open crown, and smooth and bigger leaves, with a longer leaf tip than English Elms, lighter bark and shallower fissures. Veins usually exceed 12 in a leaf.
We broke up into groups and chose an avenue of trees (Fitzroy Gardens has a number of avenues of elms trees) and started to practise our identification skills. The avenue my group looked at was mostly English Elms but when we came to the Dutch elms we weren’t as confident as there are cultivars, just to put the spoke in the wheel for a beginner. We pruned off a leaf, identified on the bag which tree it was from (there was a labelling system) and then popped the leaf into the good old resealable Glad bag and indicated on the map which tree we had taken the leaf from.
When the City of Melbourne has the answers to how much genetic diversity there is and where it is located, they will be able to initiate a propagation strategy which will ensure the genetic identify is maintained and is represented in the future Elm tree generations planted in Melbourne.
Council has recruited Citizen Foresters to assist with this and other urban forest projects. More than 200 samples have been collected by Citizen Foresters to date. If you would like to find out more or get involved, log onto the City of Melbourne’s Urban Forest.