Invercargill Airport management have requested 227 trees be removed from Queens Park due to airspace exclusion zone intrusions.
Civil Aviation Authority senior communications adviser Emily Laws said all certified airports were required to survey the areas around the aerodrome and note the presence and height of terrain, obstacles, structures, hazards and trees.
Invercargill Airport chief executive Stuart Harris said tree height on airport approach/takeoff zones was limited depending on the distance from the airport and runway approach and centre-line.
The park’s trees were not the only group affected by the Invercargill City Council district plan zoning. Otatara properties and the Otatara Golf Club on the western approach pathway were also required to keep vegetation growth within the limits.
"We’ve had ongoing relationships with a lot of the Otatara landowners and the golf club over the years and there’s a lot of ongoing management out there of trees to make sure they’re not obstacles."
Mr Harris said the airport management had been working with a lot of landcare groups involved with taking care of many of the old native trees which needed to be attended to.
"We are just making sure the native trees are being treated a bit differently out there because there’s a lot of those that are sitting very close to the limits but are also very slow growing."
Some trees on the western approach were also protected under a Queen’s covenant. Queens Park had 65 high priority trees, closest to the approach centre-line, that would be removed in the next two years.
Mr Harris said tree height limits varied across the park as it depended on their location to the centre-line approach.
"If you extend the line of the runway, it extends right through the middle of Queens Park. So anything on that line has the more onerous height restrictions. As you go either side of that the restrictions eases off.
He said it was a difficult balance to get right but believed safety needed to take priority.
The gap between planes during take-off and landing could look quite significant, especially on calm days.
"But it’s the days where it’s cloudy, really turbulent conditions and you’ve got a plane not floating directly on line... it might hit a pocket of turbulence and suddenly lose a bit of height.
"So we are making sure under those circumstances, there is a margin of error for that plane to come through without catching the top of a tree."
High trees also created turbulence above them which could also impact planes moving overhead, he said.
Council Parks and Recreation manager Caroline Rain said they had developed the 2020 Tree Plan which included developing a Queens Park tree inventory, risk management assessments and annual scoping to ensure proper management of the tree network.
By Toni McDonald
