A significant tree in Bold Park has been saved and given a new lease on life, thanks to an expert team from the Botanic Gardens and Parks Authority.
The magnificent Marri tree (Corymbia calophylla), growing near the WA Ecology Centre was experiencing a slow decline in health and vitality. Closer investigation revealed significant root damage and poor soil quality and pH levels.
Major damage, including heavy soil compaction, had occurred during the 1980s and early 1990s prior to BGPA taking management of Bold Park.
At more than 100 years old and about 18-20 metres high, restoring this towering beauty to its former glory was no mean feat and took a dedicated team of BGPA arborists, horticulturists and scientists.
BGPA Curator Arboriculture Jeremy Thomas said the Marri's age and species were big factors when considering its treatment plan.
'The sheer size of this tree meant a lot of work was required both above and below ground to provide care.
'Some species respond to treatment differently or not at all. Age is also important, as through maturity, tree function and metabolism slows and their ability to respond is challenged.'
Jeremy said he found it incredibly rewarding to be able to save a tree from premature decline and viewed the Marri project as a great experience for the staff.
'To be at ground level getting your hands dirty and see such stunning results is just priceless. Over 90 per cent of all tree problems start underground', he said.
And, as the Marri continued to flourish, Jeremy said he believed the local environment would benefit too.
'No doubt there are many other benefits from saving this tree and improving condition and Cockatoo populations will soon return to this tree for seed as it has been of poor production in recent years.'
Jeremy said the Marri tree restoration program was designed to reinvigorate the surface root system by alleviating soil compaction and reintroducing beneficial soil organics, nutrition and a customised watering regime.
The mammoth effort commenced in 2015 with the arboriculture team undertaking a two-day service of the tree's canopy to remove dead and diseased wood using safety ropes, harnesses and a cherry picker.
'The Kings Park Science team investigated leaf photosynthesis and function whilst horticulturists collected soil samples from around the Marri to assess the soil chemistry', Jeremy said.
'Using Air Spade technology the team generated horizontal mulching trenches throughout the surface root system, incorporating organic compost back into the trench lines to improve soil conditions, soil oxygen and water penetration capacities and improve general root development and condition.'
Now, less than 12 months on, its dramatic transformation has even surpassed the team's expectations of recovery.
'We did expect to see a result as the program was implemented during its growing stage of the year', Jeremy said.
'We were somewhat surprised by the fullness of the response which is clear when you look at the canopy and leaf conditions. We are still to gather more data in time to see what soil chemistry has improved and relate this back for further tree function analysis.'