Palermo LiDAR Tree Scan: 21,000 Street Trees Mapped

Palermo has completed its first LiDAR street-tree scan with greehill, delivered in close collaboration with the city and local partner R3GIS. In the defined survey area, 21,000 street trees were mapped and processed into a complete digital tree inventory, a reliable urban forestry baseline the Italian city can use for maintenance planning, early risk detection, and long-term canopy and heat strategy.

In practical terms, the city now has a consistent view of its street trees across the network, replacing partial records with measurable evidence that can be updated over time.

Why Palermo needed a new street-tree inventory  

Urban trees are operational infrastructure in Mediterranean cities. They shape thermal comfort, reduce heat exposure in public space, and influence safety along streets and plazas. Yet many cities still work with inventories that are incomplete, outdated, or inconsistent between districts. The consequences are predictable:

• maintenance follows routine, not need

• risks remain invisible until storms or heat stress force emergency action

• canopy planning is driven by assumptions instead of evidence

• budgets spread thin instead of targeting high-impact streets

  
  

A current urban tree database changes the operating mode: from reactive care to planned, defensible management.

Palermo’s street system makes this especially relevant. Dense historic corridors, wide Mediterranean avenues, and heavily paved public space create strong variations in heat exposure, soil volume, and tree stress. A city-wide inventory allows Palermo to manage these differences at street scale, where real decisions happen.

What a LiDAR tree baseline enables for urban forestry

A baseline is not a report. It is a working tool, the foundation for decisions that hold up in real streets, real budgets, real weather.

Targeted maintenance.

Palermo can prioritise inspections, pruning, and replacement based on actual distribution and measurable attributes, not habit. That improves staff efficiency when capacity is limited.

Early risk detection.

Street trees interact with traffic, pedestrians, and built structures. When positions and size parameters are complete and consistent, risk screening becomes preventive. Problems are addressed while manageable, not after they become incidents.

Canopy and cooling strategy.

Heat resilience is spatial. A baseline makes canopy data visible at street level so cooling gaps can be identified and planting can be targeted where shade demand is highest. This is the practical route to fewer heat hotspots and better use of planting budgets.

Mediterranean heat: why Palermo’s canopy data matters   

Palermo is greehill’s southernmost scan in Italy so far. Its street-tree population includes a high share of evergreen and exotic species typical for Mediterranean environments. That diversity is a strength, but it increases management complexity because:

• maintenance cycles differ widely by species

• drought and heat stress affect tree groups unevenly

• cooling performance varies strongly between streets

  
  

A consistent baseline is therefore not only about counting trees. It is about understanding variation in the urban forest and managing it deliberately.

The scan just took place in mid-November, close to the end of the growing season. Operationally, that matters: cities do not get perfect conditions on demand. Palermo’s results show that reliable inventories must work under real scheduling constraints, because climate pressure does not wait for an ideal biological window.

How the greehill LiDAR system creates a digital tree inventory 

LiDAR survey vehicles map street space in high-resolution 3D. Automated recognition pipelines detect each tree in the point cloud and extract measurable parameters such as location, height, and crown dimensions. The output is a consistent digital street-tree inventory that can be integrated into municipal workflows and used as a reference for repeat surveys.

Typical outputs include geolocated tree position, structural attributes (height, crown size), and classification layers suitable for municipal use. Standardisation is what makes future scans comparable and operationally useful.

Next steps for Palermo’s urban forest management 

Before full delivery of the dataset in early 2026, Palermo has already prepared additional budgets for 2026 and 2027 to expand scanning into further areas. That signals a shift from pilot thinking to infrastructure thinking.

With the baseline in place, Palermo can now:

• align maintenance budgets with measurable need

• reduce exposure in high-risk corridors before extreme weather hits

• plan canopy growth where cooling demand is highest

• track change over time instead of relying on snapshots

Palermo’s first LiDAR baseline provides a quantitative foundation for proactive street-tree management. It supports structured maintenance, early risk screening, and a spatially informed canopy strategy especially relevant under Mediterranean heat and climate volatility. Repeat scans can build on this baseline to track canopy change, evaluate interventions, and tie budgets to evidence rather than assumptions.

FAQ 

What is a LiDAR street-tree scan?

A LiDAR scan uses laser sensing from street level to capture trees and surrounding public space in 3D. The resulting point-cloud data is processed into measurable tree attributes and a structured street-tree inventory.

How does a digital tree inventory help a city?

It enables targeted maintenance, preventive risk screening, and canopy planning based on consistent evidence. Cities can prioritise limited staff time and budgets where the operational and climatic impact is highest.

Why is canopy data crucial in Mediterranean cities like Palermo?

Because shade and evapotranspiration directly reduce street-level heat. Without spatial canopy data, cooling gaps cannot be identified or addressed strategically.