Old Growth Arboriculture

Two ash trees in the same front garden can look near enough identical and be worlds apart in law and in behaviour. Desert Ash counts as an invasive problem species; Claret Ash does not. Swamp Sheoak suckers and puts invasive roots under your paving, while the very similar River Oak is treated as a beneficial tree. Getting the name right is the first step in every legal, maintenance and management decision that follows it, so I will inspect and identify a tree with a verbal or written report, and key out the harder ones, the cultivars, the Cupressaceae and the less common ornamental eucalypts, on vegetative and reproductive characters. Behind that sits a PhD in plant taxonomy, former experience as an identification botanist at a state herbarium, and a database of more than 200 tree species commonly cultivated in the greater Adelaide region, compiled for Old Growth Arboriculture.

I'm Dr Gregory Guerin, an AQF Level 8 arborist, botanist and forest ecologist with a quarter of a century in those fields. First class honours in botany and a PhD in taxonomic botany from the University of Adelaide, a Graduate Certificate in Arboriculture from the University of Melbourne, and more than 80 published articles on plant taxonomy, vegetation, plant biodiversity and forest health in peer-reviewed journals. I carry $20 million public liability and $5 million professional indemnity, hold a white card, a national police check and a working with children check, and I'm a member of Arboriculture Australia.

The formal side is the documentation your project will be asked for. Arborist reports and tree risk assessment, preliminary reports, retention value, arboricultural impact assessments, tree protection plans and monitoring and certification for development sites under AS 4970-2009, along with tree audits, inventories, health monitoring and tree management plans. You'll need something in writing if you want to remove or substantially trim a protected tree, if you're subdividing, building, demolishing or putting utilities in where trees are present, or if a neighbour matter has reached that point. It pays to get independent advice before you contract expensive works.

Formative pruning is best done in youth, when the cuts seal with active defences and occlude within a season, and it guides growth away from double leaders, weak attachments, included bark and crossed branches before any of them turn structural. Corrective pruning, canopy lift and clearance work around driveways, parking spaces and buildings all preserve the shape and the future health of the tree. Heavy pruning and topping look impressive for a season, then stress the tree into a proliferation of weakly attached adventitious growth that needs cutting again the following year, and can end in decay. A patient, low impact approach is better for the tree and cheaper for you, and it can often be done without a large truck, a chipper and a crew turning up at your gate.

Older trees get their own program: health monitoring, management of nutrition, disease, water, soil compaction and site access, enhancing limb retrenchment to renew a crown, and palliative care through natural senescence. After a storm I triage damaged trees to work out whether the tree is still viable, what residual safety issues are left and what pruning or management the aftermath needs. Pest and disease management belongs here too, and at the other end of the cycle I write species selection reports matched to the light, soil, space, infrastructure and water on a site.

My work covers the whole of the greater Adelaide region and runs into country South Australia for significant projects, with core areas in north-eastern Adelaide and the peri-urban Mount Lofty Ranges, out of Tea Tree Gully. Basic maintenance can be carried out at the time of the inspection, with written recommendations or specifications prepared where the works are more involved. Get in touch to book an inspection, talk a tree matter through, or ask for a free quote.