Research analysing 370 front yards and gardens in Northern Sydney and Greater Western Sydney where older houses in low density residential zones were demolished and replaced with new and larger detached houses reveals a stark pattern: developers are systematically prioritising built form over green space.
On average redevelopment resulted in a 46 per cent reduction in garden area, 57 per cent increase in front hardstand driveway area and a 62 per cent loss in canopy area. The data paints a troubling picture of what has become standard practice in Sydney's middle-ring suburbs.
The research, compiled in an academic paper authored by Peter Davies, Adrienne Keane, and others, exposes a critical planning tension. While local council policies exist to protect the front garden and enhance the landscape character of the residential area, in practice these controls are subjugated to state government planning controls enabling larger houses that occupy lots to the greatest extent possible, maximising the development envelope, while gardens and canopy trees are relegated to secondary priority.
This matters beyond aesthetics. Sydney faces a significant challenge in meeting its environmental goals. Greater Sydney's tree canopy has increased from 21 per cent in 2019 to 21.7 per cent in 2022, but more than 8 million new trees are needed to meet the 40 per cent canopy cover target. Yet knockdown rebuilds are moving in the opposite direction.
The problem is particularly acute in leafier suburbs. Every council except Mosman with 30 per cent or more canopy cover in 2019 experienced canopy loss by 2022, with the highest losses in Ku Ring Gai, Northern Beaches, Sutherland Shire and Wollondilly. These are precisely the areas experiencing the greatest knockdown rebuild activity.
Council policies acknowledging the importance of trees and gardens exist. But they struggle against state-level planning frameworks that reward maximum site utilisation. A new house filling most of the block generates more development value. A front garden generates none.
There is a legitimate argument for housing density: Sydney needs more homes. Larger houses on the same blocks mean households can stay in established suburbs they prefer, rather than sprawling outward or relocating. Knockdown rebuilds avoid the environmental cost of greenfield development.
Yet this does not require sacrificing gardens entirely. The research suggests a false choice is being imposed. The growing emphasis on canopy targets reflects broader changes in how cities are planned, with urban heat, infrastructure stress, and declining environmental resilience having become central planning concerns, and tree canopy increasingly viewed as part of essential urban infrastructure supporting thermal comfort, stormwater management, and long-term liveability, and assessed alongside density controls, transport planning, and service capacity.
The data suggests planning controls should be rebalanced. If local councils value front gardens and canopy, state planning policy should enable them rather than make them the exception. Some councils are responding. Since 2022, most local government areas have adopted a Vegetation Management Plan aligned with Tree Protection Order reforms, and in 2025, Blacktown Council piloted real-time permit dashboards while Ku-ring-gai introduced drone-based audits to track canopy loss.
The message from the research is clear: Sydney cannot simultaneously maximise housing density, demolish established trees systematically, and meet its canopy targets. Policymakers need to choose what matters most, and design planning controls that deliver on that choice rather than hoping markets will balance values that planning itself has rendered unequal.