Europe is now in its third major heatwave since May 2026. A stable heat dome has settled over Western and Southwestern Europe, pushing daytime temperatures 10 to 15°C above historical norms across Spain, Portugal and France, with the heat expanding north into Germany, the UK and beyond. Soil that was already dry after a record-breaking spell in May has had little chance to recover.
Most public attention during a heatwave goes to people: heat alerts, cooling centres, health guidance for vulnerable residents. That focus is appropriate and necessary.
But there is a second, quieter effect that repeated heatwaves have on cities, one that gets far less attention: they change the condition of the urban forest. And in most cities, urban tree management still isn’t built to track that change as it happens.
Why Traditional Urban Tree Management Falls Behind in Summer
Urban tree management has historically run on an annual rhythm: inspect, prioritise, plan, maintain, repeat. That rhythm was designed for conditions that changed slowly and predictably across seasons.
Repeated, prolonged extreme heat breaks that rhythm.
A heatwave doesn’t affect every tree the same way. Some trees develop drought stress. Others become more vulnerable to pests or move faster toward structural decline. A tree that was a low priority in May can become a high priority in July, not because anyone re-inspected it, but because conditions changed underneath it.
If a city’s tree data only updates once a year, that city is, by definition, working from outdated priorities exactly when conditions are moving fastest: during summer.
Three Questions That Define Modern Urban Tree Management
The difference between cities that manage trees well and cities that struggle under changing conditions comes down to three operational questions.
1. Can the city see which trees have changed since the last heatwave, not since the last inspection?
Tree condition doesn’t wait for a scheduled site visit. A tree that looked healthy in spring can be under measurable drought stress within weeks of extreme heat. Urban tree management that only updates annually can’t catch that shift until it’s already several months old.
2. Can the city reprioritise maintenance and inspections within weeks, not at the next planning cycle?
Even cities with solid tree inventories often can’t act quickly on new information, because their planning processes are built around annual or seasonal cycles. Knowing a tree has become urgent doesn’t help much if the earliest opportunity to act on it is the following spring.
3. Can the city identify which tree has just become urgent, before something fails?
This is the difference between proactive and reactive urban tree management. Trees generally don’t announce that they’ve become a priority. Without a way to detect the shift, the first signal is often a resident’s report after a branch has already come down.
If a city can’t confidently answer “yes” to all three, the underlying issue is rarely a lack of commitment to trees. It’s that the management model wasn’t built for conditions that change this quickly, this often.
Why Planting More Trees Isn’t the Fix
For decades, urban forestry strategy has rightly centred on planting, expanding canopy cover, choosing climate-resilient species, greening streets and public spaces. That work remains essential and nothing here argues against it.
But planting solves a different problem than the one repeated heatwaves are exposing. More trees in the ground doesn’t help a city that can’t see which of its existing trees have become higher-risk this month. A maintenance plan updated once a year doesn’t help a city that needs to reprioritise within weeks.
This is a growing recognition across the sector: the global urban forestry software market was valued at roughly USD 96 million in 2025 and is projected to keep growing, driven in part by municipalities investing in tools that go beyond static inventories toward continuous, data-driven tree management. Resilience isn’t created by planting alone, it’s created by knowing which interventions are needed, where, and when.
Managing Trees as Living Infrastructure
Roads and streetlights are infrastructure that mostly stays the way it was built. Trees are infrastructure that keeps changing with weather, with age, with stress. Effective urban tree management increasingly means treating trees the way cities already treat other critical infrastructure: with continuous condition data, not periodic snapshots.
This is the focus of greehill’s work. Using AI-powered digital twins of urban trees, generated from street-level LiDAR data, greehill helps cities move from static, once-a-year inventories toward a continuously updated understanding of tree condition, risk and priority so that when conditions shift, as they have three times already in 2026, the city’s response can shift with them.
This summer 2026 is showing which cities can adapt their urban tree management as quickly as their urban forest is actually changing.
Frequently Asked Questions
How often should a city’s tree data actually be updated?
There’s no single fixed answer, but the more useful question is whether the update frequency matches how fast conditions change. Annual inventories work reasonably well in stable years; during repeated heatwaves, condition and risk can shift meaningfully within weeks, which is faster than most municipal planning cycles can react to using a once-a-year dataset.
Does this apply to smaller cities and towns, or only large municipalities?
The underlying problem, condition data going stale faster than planning cycles can act on it, applies at any scale. Smaller municipalities often have fewer trees to track, but also fewer staff to re-inspect them manually, which makes continuously updated data arguably more valuable per staff hour, not less.
How is greehill’s approach different from a traditional tree inventory?
A traditional inventory is a snapshot: a count and condition assessment captured at one point in time, then used until the next scheduled survey. greehill generates AI-powered digital twins of urban trees from street-level LiDAR data, producing condition and risk information that’s updated on an ongoing basis rather than fixed until the next manual re-survey.
Learn more about how greehill helps cities manage urban trees as infrastructure at www.greehill.com.
