When using a crane to dismantle and remove branches from a tree, there are a few different methods and techniques to consider.
Joe Harris from Into Trees participated in Vermeer Australia’s Arborist Seminar Series last year, talking through the balance branch lift technique, and best practice for arborists to use this method safely and efficiently. Here is some of what he had to say.
The right sling for the job
There are two different types of slings that can be used when lifting a branch: chain or textile loop slings.
“Chains can come in different sizes and lengths, and it’s common to have two to four different sized chains attached to the crane hook to balance the branch,” Joe says.
“The main issue with chains is that they can create a lot of slack, which can be hard to manage and manipulate lengths. Wrapping or shortening the chain can work, but this can still cause issues with managing the length.
“Textile loop slings are super light and easy to manipulate compared to chains. They are also safer for climbers – if they are to swing from a branch they are not as heavy or dangerous.”
Joe says the right choice depends on your preference and what is available at the time of the job, but textile loop swings are his preferred option.
How to sling a branch for a balance lift
Joe says there are a couple of key elements to a successful balance lift using a textile loop sling.
“First, you need to ensure your sling is set at the centre of gravity of the tree. Then, depending on the size of the branch, use different lengths and slings and space them out across the branch to ensure balance. Your longer sling should also be positioned at the blunt end of the branch so there is slack when the branch is cut and lifted.”
Joe also says when positioning your shorter slings, ensure they are angled at around 90° between the longer slings to assist with the removal. Your pre-load weight of the crane also comes into play here, which will determine positioning of the slings (Fig. 1).
Different cuts for different branches
“Now you have your branch slings set, and your crane weight pre-loaded, it’s time to cut the branch. There are a few different cut techniques when using the balance lift, and the right one depends on the type of branch, and the area you’re working in.”
Straight cut through
This is the simplest cut. Can be made top-down or bottom-up (Fig. 2).
Bottom cut inboard of top cut. This creates a step or lip to stop the butt ‘kicking up’ at the climber. There can be different variations of this depending on pre-load weight (Fig. 3).
Stops the butt kicking up or dropping down. Start with undercut, then finish with a top cut last (Fig. 4).
To find out more about Vermeer Australia, including more information on the Vermeer Australia Arborist Seminar Series, head to vermeeraustralia.com.au