Ku-ring-gai, and the forest it protects
Pymble sits on the Wianamatta shale ridge in Ku-ring-gai Council, which runs the most restrictive tree controls in New South Wales. The threshold at which a tree becomes protected is low, the exempt list is short, and significant pruning is treated similarly to removal.
The reason is under your feet. This ridge carried Blue Gum High Forest — Sydney blue gum, blackbutt and turpentine growing to forty metres on deep shale clay — and only fragments survive anywhere. Those remnants are a critically endangered ecological community with state-level protection on top of the council's own rules. Sydney Turpentine-Ironbark Forest occurs in patches here too.
The result is that a Pymble job usually begins with paperwork rather than a quote.
The trees on a Pymble block
Half-acre garden blocks along the streets off the Pacific Highway commonly hold two or three mature eucalypts that predate the house. Blue gum and blackbutt dominate, with turpentine on the moister aspects and the occasional enormous Sydney red gum on the sandstone fringe where the land falls toward Lane Cove National Park.
Underneath them sits an interwar or Federation roof and, quite often, a mature exotic garden planted in the 1950s — camphor laurel, liquidambar, jacaranda, privet. The weed species among those are the exceptions that get straightforward approvals.
What good pruning looks like here
Reduction pruning to Australian Standard AS 4373: each cut placed back to a lateral branch big enough to take over as the new leader, so the wound seals and the tree keeps a sensible structure at a smaller size.
Topping a blue gum — cutting limbs to stubs at a chosen height — produces dense epicormic regrowth anchored only in the outer wood. Within five to ten years that regrowth is heavier and more failure-prone than what it replaced. On a protected tree it is also likely to be an offence in its own right.
For most Pymble trees the highest-value work is not reduction at all. It is systematic deadwooding and the removal of specific defective limbs, which reduces the real risk without the council process that a large reduction attracts.
Timing and access
Late winter into early spring is the best window for reduction work, ahead of the growth flush and before summer heat stresses the tree further. Deadwooding can be done any time.
Access on the ridge is generally workable — wide streets, long driveways and room for a chipper. Blocks on the western fall toward Lane Cove National Park are different: the ground drops away behind the house and material has to be carried uphill.
Nearby
Turramurra is the next suburb north under the same council, Wahroonga covers removals, and the North Shore region page covers the councils. See what lopping should mean for the method.
Ring (02) 9000 1943, or check the cost guide.
Other numbers for this area
You can also reach us on (02) 9538 7842. Either number reaches the same team - tell us the suburb and what the job involves and we will get an arborist out to look at it.
Frequently asked questions
Do I need approval just to prune a tree in Pymble?
Often, yes. Ku-ring-gai treats significant pruning with much the same seriousness as removal, and the size threshold at which a tree becomes protected is low. Minor deadwooding and work on listed exempt species is generally fine. Anything that materially reduces a protected tree's canopy needs checking against the current development control plan first.
How much can be taken off a mature blue gum?
As a working rule, no more than about a quarter of the live crown in one season, and less if the tree is already stressed. Removing much more starves it and provokes a flush of weak epicormic regrowth. If you need a large reduction, it is staged across two or three years, which is also easier to get approved than one drastic cut.
Is deadwooding easier to get approved than reduction?
Generally yes, and on a mature Pymble eucalypt it also addresses most of the actual risk. A dead limb in a forty-metre blackbutt is heavy, brittle and comes down without warning. If your concern is a specific dead limb over the house rather than the tree's overall size, say so — it is a simpler job and a simpler approval.