Auckland City’s Quay Street is getting a makeover as part of the Downtown Transformation project. Last year, in conjunction with JFC, our AirX trucks were used to remove five mature Pohutukawa trees from along Princes Wharf. After 30-40 years, the trees were a pretty decent size: they ranged between 8-10m tall and one had a canopy spread of 5m. The rootballs alone were around 3.8m wide by 60cm deep.
The plan was to move the trees off-site for a year before reinstating them once the transformation is complete, so extreme care was necessary when digging out. Before work started on each tree, a meeting was held with expert arborists to discuss strategy, mainly around avoiding the main tap root.
To add to the challenge, at some point the trees had large amounts of concrete poured around their base, constricting their growth. This needed to be carefully broken away with jackhammers, without affecting the roots.
Complicating things further, there were large services running through the concrete and tree roots — both power and gas — that would be catastrophic if hit.
“This was definitely a job for our AirX,” says the HydroVac project manager overseeing the job. “The stakes were too high to have a digger doing the work, and flooding the hole with water with hydro-excavation wasn’t an option with the services running through the job. Air excavation is ideal for these kinds of jobs. Air is a powerful excavator but gentle enough to work around dangerous in-ground services as well as not harming even the finest roots.”
An air lance was used first, to locate all the roots – an air lance is a bit like a waterblaster but using compressed air instead. Once the main roots were exposed by the air lance, the arborist would determine the best place to fit the 10-inch boom in. Air-excavation was employed until the root ball was exposed, about 1.5-2m deep, before a crane carefully pulled each tree from the site and put it on the back of a truck.
Excavation and removal took between 1-3 days per tree.
Watch this cool short video on the process HERE
Some facts about our AirX air-excavation trucks:
- They offer very high vacuum – 25000 CFM (compared to 1800-5000 CFM with hydro)
- They have a generous 10-inch boom which allows you to suck very big product without getting boom blockages. They can vacuum up bowling-ball sized dirt!
- They vacuum up/remove the dirt as they excavate
- Excavated soil can be reused on site or removed
- If you choose to remove and dump the excavated soil, it costs less as a
dry material, without water adding weight like it does with hydro-excavation
- HydroVac’s trucks are fitted with a unique filtration system that doesn’t emit dust to the atmosphere when operating – helpful in residential situations
- Air doesn’t damage roots, whereas water skips the bark off the trunk and roots
We’ve also used our AirX trucks to carefully remove large trees to make way for new roads, driveways, or to move them to another part of a house site. To enquire about our AirX services, please contact your nearest HydroVac office HERE