How cities are moving from one-off inventories to continuous urban forest management.
Not long ago, most tree inventories were treated as one-off projects. For many of our clients, that is still the right starting point, and a single, well documented Smart Tree Inventory already brings enormous value: a clear record of what trees exist, where, and in what condition.
At greehill, we are increasingly seeing a second pattern emerge. Some cities are returning to update the same trees several years later. Instead of treating the inventory as a completed project, they are beginning to use it as the foundation for continuous urban forest management. That shift is closely linked to advances in digital tree inventories.
At greehill, a Smart Tree Inventory combines mobile LiDAR scanning with AI-based analysis to create a detailed digital record of every tree. Instead of relying exclusively on manual field surveys to build an inventory, cities receive consistent information about tree location, species, dimensions, canopy structure and condition across their urban forest.
The value of repeated measurements lies not in collecting more data, but in collecting comparable data. If inventories are created using different methods, different levels of detail or different definitions, identifying real change becomes difficult. Using the same workflow over multiple years creates a consistent record that allows cities to distinguish genuine change from differences in measurement.
In Germany, that shift is becoming visible across three of our projects: Berlin, Leipzig, and Amberg.
Berlin: from baseline to update
In the boroughs of Friedrichshain and Kreuzberg, we first scanned 16,700 street trees for Berlin in 2023. Three years later, the district’s tree management office asked us to scan the same trees again.
That decision adds a new layer to data that was already valuable on its own. The 2023 scan gave Berlin a clear starting point. The 2026 update turns that baseline into a point of comparison, allowing changes in individual trees and the wider canopy to be measured rather than inferred.
Leipzig: building a time series
We have now scanned Leipzig’s street trees three times: in 2022, in 2023, and again in 2026. What began as a single dataset is becoming a long-term record of change, allowing the same trees to be observed over multiple years.
The same pattern applies to Leipzig’s park areas. We scanned a park in 2022, followed by the Südfriedhof cemetery in 2023, covering 7,869 trees. In 2026, the scope expanded again to include three additional cemeteries, where roughly 2,500 cemetery trees are expected.
Amberg: from pilot to citywide record
Amberg’s story starts differently and shows just as clearly why a first scan matters. Last year, we scanned a single park area as a pilot. Based on the results, Amberg decided to expand the approach across its entire public tree population: around 11,000 street trees and 4,000 park trees, covering the whole city.
For Amberg it is the city’s first complete Smart Tree Inventory for its entire public tree stock, creating a citywide baseline that can support future monitoring whenever the city decides to update it.
Repeated measurements answer additional questions
Across all three cities, we use the same underlying method: LiDAR vehicle scanning, using both car and Polaris based platforms, combined with AI analysis to extract individual tree data.
A single Smart Tree Inventory already answers essential questions: what trees exist, where, and in what condition. Repeated measurements answer additional questions on top of that: how trees are developing, where decline is beginning, and how storms, heat or maintenance are affecting the canopy over time.
When cities choose to rescan, they move from a strong benchmark towards more long-term urban forest management. Repeated inventories help cities identify where canopy is expanding or declining, understand the effects of drought or storms, evaluate maintenance programmes and prioritise inspections based on measurable change rather than assumptions. Instead of reacting only when problems become visible, urban forestry teams gain evidence that supports earlier and more informed decisions. This does not replace expert judgement, but it gives arborists and urban forestry teams stronger evidence to support it.
Two valid starting points, one shared foundation
Together, these three cities illustrate different stages of the same journey. Amberg is establishing its first citywide record. Berlin is beginning to compare that baseline over time. Leipzig is demonstrating what becomes possible once repeated measurements start building a genuine historical record. Two valid starting points, one shared foundation.
Whether a city is scanning its trees for the first time or returning to update a previous inventory, both are meaningful steps toward better informed urban forest management. A first scan turns unknowns into a clear picture. A second or third scan turns that picture into a story of change.
Urban trees never stop growing, responding to drought, storms or maintenance. It is therefore increasingly difficult to manage them using information that remains unchanged. A Smart Tree Inventory provides the foundation. Repeated measurements turn that foundation into an evolving understanding of the urban forest, allowing cities to manage their urban forest as the living infrastructure it is.
The experiences of Berlin, Leipzig and Amberg show that there is no single path towards better urban forest management. Some cities begin by creating a reliable baseline. Others return years later to understand how their urban forest has changed. Both approaches create value. Together, they show how a tree inventory can evolve from a one-time project into a long-term operational asset, supporting better decisions year after year.
