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News from BARB, the BGANZ Arboriculture Professional Group
We speak for the trees. The role of arborists in botanic gardens and the value of our trees.
Ian Allan, Chair BARB and Supervisor Natural Areas & Arboriculture, Blue Mountains Botanic Garden, Mount Tomah
For most visitors to our amazing botanic gardens, the trees frame their experience. From picnicking and taking respite from the hot summer sun in their shade, frolicking in fallen autumn oak leaves, pondering ancient lands where trees like the Wollemi Pine were once common, or watching the birds in hollows atop towering eucalypts, people connect with our trees in deep and long lasting ways. Often, they are the most dominant plants in our landscapes — their presence is undeniable — yet many people are not aware of the benefits trees provide them, and even fewer people know who looks after our trees and how we do it.
Our tree collections and the naturally occurring trees provide a vast array of benefits to society and the environment. Public awareness of the importance of trees has seen a massive upsurge in recent years, with even primary school aged kids learning about carbon sequestration, ‘forest bathing’, habitat trees and the efforts to save the Wollemi Pine from extinction.
As arborists and tree managers in botanic gardens, we have committed ourselves to the life of the Lorax — speakers for the trees. As the BGANZ Arboriculture (BARB) Professional Group, we are committed to advocating for both the trees AND the arborists. Across our network of highly qualified and expert arborists, we put our skills and knowledge to work daily to ensure our trees, and the benefits they give us, can continue to grow and be maintained sustainably for generations to come. We garden our trees, but we also do a whole lot more …
Just like the shrubs and lawns in our gardens, our trees need care and maintenance (as some of the longest living plants in our collections that provide the most benefits, one could make the case they deserve even more care!). Our experts mulch our trees to ensure they have healthy soil to support their growth, we carry out decompaction works using specialist, science based techniques, we do all types of pruning, pest and disease management, planting, and on top of that, we manage comprehensive living collection record keeping systems that set us apart from your average garden or park.
Many people know that arborists prune and remove trees due to risk, and of course our arborists do that too. Some of the arborists in our network are highly qualified, leading experts in managing tree risk. I like to think this is so we can educate people on the proportionally low risks from our trees and balance those risks with the amazing benefits our trees provide. When we do that well, we can get on with the tree management work that is unique to arborists in botanic gardens.
Many of our experts are qualified consulting arborists. They play important roles in guiding their organisations in balancing the pressures and impacts on our trees from the increased use of our gardens, and the development of facilities and infrastructure, to ensure the benefits and value of our trees are maintained.
At Kings Park and Botanic Garden in Western Australia, BARB Treasurer/ Secretary Chelsea Payne and her team of arborists are playing a key role in the biosecurity response to the arrival of a wood boring pest, Polyphagous Shot Hole Borer, that threatens to heavily impact Australia’s trees and our urban forests.
At Royal Botanic Gardens Victoria, BARB Committee Member Peter Berbee and his colleagues are involved in the Global Conservation Consortia for Quercus. They are building their Oak conservation collection and distributing it throughout the BARB network to secure wild sourced oaks that are incredibly difficult to import into Australia (to read more about this, click here).
At Botanic Gardens of Sydney’s gardens, arborists including BARB Committee members Matt Coyne from Royal Botanic Gardens Sydney, and myself from Blue Mountains Botanic Gardens, Mount Tomah, play important roles in the conservation efforts to save the Wollemi Pine and in providing arboricultural advice on growing and maintaining this ancient tree.
Many of our arborists are providing advice on habitat tree management and developing habitat trees in our gardens for endangered bird species such as Gang Gang cockatoos.
Our colleagues across the Tasman in New Zealand are also doing incredible work on Kauri Dieback and managing ancient veteran Rimu trees.
These are just a few examples of the breadth and depth of what botanic gardens arborists are doing for our trees and some of the benefits our trees and tree management teams provide. Our trees and our arborists are clearly of great value, but just to drive it home, we can quantify some of these benefits in dollars.
BARB is working with BGANZ to look at ways we can quantify some of the economic benefits our trees provide, even just in terms of carbon sequestration and pollution capture. Early ballpark figures using peer reviewed online tools indicate the trees in just one of our member gardens provide hundreds of thousands of dollars of those benefits each year. There has also been some work on determining dollar values of individual trees by arborists at several member gardens. Based on recognised tree valuation methods, it would be reasonable to value just one moderately sized mature tree in one of our collections at tens of thousands of dollars. I’m better at looking after trees than I am at maths, but the value of our trees in BGANZ gardens and the benefits they provide is definitely well into the tens of millions of dollars.
With an asset like that, we hope we see the continued support of our arborists and the resourcing of specialist arboriculture teams for the gardens that don’t have them.
BARB is committed to providing network support to all our member gardens to help with whatever tree management issues they have. For a contact list of BARB arborists, please email me at ian.allan@botanicgardens.nsw.gov.au.
