Is Killarney Heights Slowly Losing Its Trees?

Why we need to start measuring the changes to our leafy suburb

One of the things that makes Killarney Heights special is something that is easy to take for granted: trees.

Our streets are lined with mature native trees. Bushland surrounds the suburb. From many parts of Killarney Heights, the landscape blends seamlessly into the forested slopes and waterways around Middle Harbour.

The trees are not simply decoration. They are part of the character and identity of our suburb.

They provide habitat for birds and wildlife, shade our streets and homes, help reduce urban heat and contribute to the distinctive landscape that makes Killarney Heights such a desirable place to live.

But are we slowly losing them?

A changing landscape

Over recent years, many residents have noticed trees disappearing from properties around Killarney Heights.

Some removals are obvious. Others are less noticeable.

A large tree may disappear during a renovation. A backyard may be cleared as part of landscaping. Trees may be removed to open up a garden or improve a view towards Middle Harbour.

Importantly, this isn't necessarily about new development.

A house can remain standing while the landscape around it changes considerably.

One mature tree can take decades to replace. If one tree is removed from one property, the change might seem insignificant. But what happens when this occurs across dozens or hundreds of properties over many years?

That is the question we should be asking.

We need to know what is happening to our canopy

Northern Beaches Council has stated that the Northern Beaches has an estimated 12 million trees and that protecting and enhancing tree canopy is a priority. Council's Tree Management Policy, adopted in 2025, aims to support the retention of healthy trees, replacement planting and increased tree cover.

Council also publishes information about tree removal and pruning on private land, including the circumstances in which approval is required.

These are important commitments.

But from a community perspective, there is another question:

How do we know whether the tree canopy of individual suburbs is actually increasing or decreasing?

It is one thing to know that the Northern Beaches has millions of trees.

It is another to know what is happening in Killarney Heights.

Are we gaining trees or losing them?

Has canopy cover changed over the last five, ten or twenty years?

Which parts of the suburb are changing?

How much canopy is being lost on private land?

And are replacement trees actually replacing the canopy that has been lost?

At the moment, these questions are difficult for residents to answer.

What if we could see the change?

Modern spatial technology makes this much easier than it once was.

High-resolution aerial imagery, satellite imagery, LiDAR and geographic information systems can be used to measure tree canopy across an entire suburb.

Rather than relying on individual observations, Council could establish a baseline tree canopy measurement for every suburb and then repeat the analysis regularly.

For example:

Killarney Heights
Tree canopy: 43%
2026 baseline

Then, five years later:

Killarney Heights
Tree canopy: 40%
Change: -3 percentage points

Suddenly, the community has something tangible to discuss.

The same information could be provided for every suburb across the Northern Beaches.

That would allow residents, Council and elected representatives to see where canopy is being retained, where it is declining and where additional planting may be needed.

There are already Australian companies that can do this

This isn't a theoretical idea.

Australian geospatial companies such as The Spatial Distillery Co. already provide tree canopy analysis and urban forest mapping services to local governments.

Their work combines high-resolution imagery, remote sensing, LiDAR and spatial analysis to answer questions such as:

• Where is tree canopy today?

• Where are the gaps?

• Where could new trees be planted?

• Which communities are most exposed to urban heat?

• How is canopy changing over time?

• Are canopy targets being achieved?

The Spatial Distillery Co. – Urban Forest & Sustainability

For a place like Killarney Heights, this technology could provide a fascinating picture of how our suburb is changing.

It could even allow us to look beyond simply counting trees.

We could understand where canopy is being lost, where it is being gained and what that means for shade, biodiversity and urban heat.

Transparency doesn't have to mean stopping change

This isn't an argument that every tree should be protected forever.

Trees sometimes need to be removed.

There are legitimate reasons for tree removal, including safety, tree health, construction requirements and other property considerations. Council's current policy recognises the need to balance tree protection with these practical realities.

Nor is this about criticising individual residents.

Homeowners make decisions about their own properties for many different reasons.

The issue is the cumulative impact.

If hundreds of individually reasonable decisions gradually reduce the canopy of a suburb, the end result can still be significant.

And without measuring the change, we may not realise what is happening until much of the landscape has already changed.

Killarney Heights is more than its houses

Our suburb has a story.

The bushland, waterways, wildlife, streetscapes and mature trees are all part of that story.

For Killarney Heights Heritage & Outdoors, preserving an appreciation of this landscape is an important part of understanding our local heritage.

When we talk about heritage, we often think about old buildings, historic sites and stories from the past.

But the landscape itself is also heritage.

Some of the trees that surround us today were here long before many of our houses were built. Others have grown alongside the suburb as it developed.

If we want future generations to experience Killarney Heights as the leafy, bushland suburb we know today, we need to understand how that landscape is changing.

A simple request to Northern Beaches Council

We would like to see greater transparency around the Northern Beaches' tree canopy.

In particular, we would like Council to consider:

1. Establishing a canopy baseline for every suburb

Measure the current percentage of tree canopy across each suburb, including canopy on private and public land.

2. Publishing the results

Make suburb-level canopy information publicly available through an easy-to-use online map or dashboard.

3. Measuring change regularly

Repeat the analysis every few years so residents can see whether canopy is increasing or decreasing.

4. Tracking canopy loss and replacement

Where practical, provide information on tree removals and replacement planting so that the community can understand the bigger picture.

5. Identifying canopy hotspots

Show which suburbs and neighbourhoods are experiencing the greatest canopy loss and where additional planting could make the biggest difference.

This would align well with Council's stated commitment to protect and enhance the Northern Beaches' green canopy.

Let's measure what we value

Killarney Heights has a remarkable combination of suburban life, bushland, wildlife, waterways and history.

We shouldn't have to rely solely on anecdotal observations to understand whether that character is changing.

If tree canopy is important to the Northern Beaches, let's measure it.

And if we can measure it, let's make the results visible to the community.

A simple suburb-by-suburb canopy dashboard could give residents a much clearer picture of what is happening to our green landscape over time.

It would also give Council something valuable: the ability to identify trends early and target planting and protection efforts where they are most needed.

The technology already exists.

The data can be collected.

The opportunity now is to make it transparent and accessible to the people who live here.

Killarney Heights is our home. Its trees are part of what makes it special.

Let's make sure we know what is happening to them.