Now that the plan is at its halfway point, the more useful question isn't "are we on track?" It's whether the targets set in 2017 are still the right ones.
That distinction matters because tree decisions made now won't show their consequences for decades. The halfway mark is an opportunity to ask whether the strategy is still aligned with the urban forest Barcelona set out to create before another decade of decisions locks today's priorities into tomorrow's urban forest.
What the plan actually set out to do
Most tree strategies are judged on one number: canopy cover. Barcelona's plan resists that because rather than focusing only on canopy cover, the plan combines three objectives: expanding canopy, improving climate resilience, and strengthening species diversity. By 2037, the city aims to increase canopy cover by five percentage points, reaching 30% of its surface area, ensure that 40% of its tree species are climate-adapted, and limit any single species to no more than 15% of the urban forest.
Developed jointly by Barcelona's Department of Green Areas and Biodiversity and the Area of Urban Ecology, the plan provides a management framework for more than 300,000 municipally managed trees, one of the largest municipally managed urban tree populations in southern Europe.
Why the combination matters more than any single number
A city can hit a 30% canopy target with a handful of fast-growing species and call it done. It would look good on a dashboard but if those species aren't climate-adapted, the canopy thins out exactly when the city needs it most. Cities that lean too heavily on one species can lose large parts of their canopy to a single pest, pathogen, drought, or climate shock.
Barcelona's plan treats canopy, adaptation, and diversity as one decision, not three separate targets. That combination, not the 30% figure on its own, is what makes it interesting.
Where this shows up in practice
This is where the plan either becomes part of everyday management or remains a strategy document.
- Procurement. A 15% species cap only works if nurseries can actually supply that many different species years ahead of planting season, not the two or three that are always in stock.
- Maintenance. A climate-adapted tree that's under-watered in its first years won't deliver the resilience it was chosen for. Budgets need to follow the trees carrying the plan's long-term weight, not just the oldest or most visible ones.
- Monitoring. Canopy cover is easy to track by satellite. Species health under real heat and drought is not and without that data, a city can look on-target for years while quietly drifting off it.
- Funding. A twenty-year plan gets financed in two- and four-year budget cycles, across administrations with different priorities. A tree planted under one mayor is rarely still being monitored with the same consistency by the next.
Ultimately, this is where most long-term tree strategies succeed or fail.
Worth re-checking at the halfway point
A decade of warming across the Mediterranean may have already outpaced the "climate-adapted" species list the plan was built on, and a decade of pest pressure could mean the 15% ceiling deserves a second look. Two questions are worth asking directly:
- Can nurseries actually deliver the species mix the plan calls for, or has real-world availability quietly narrowed what gets planted?
- Does monitoring track tree health, or only canopy area?
None of this undercuts what Barcelona set out to do. Treating canopy, species mix, and diversity as one system put it ahead of most comparable city plans, and its approach has since been cited in UNECE's work on urban greening. But good design in year one doesn't guarantee alignment in year ten, that's what a midpoint review is for.
The broader point
The bigger question isn't how many trees are planted this year. It's whether today's procurement, maintenance, and monitoring decisions are still aligned with the forest the city will need thirty years from now. A twenty-year strategy should be measured not only by whether it is being followed, but by whether it is still pointing in the right direction.
The views expressed are those of the author and are intended to contribute to professional discussion on urban forestry and climate adaptation.
Further Reading
- Barcelona City Council. Trees for Life: Master Plan for Barcelona's Trees 2017–2037.
- UNECE. 3-30-300 Rule for Greener Cities.
- C40 Cities. Urban Nature Knowledge Hub.
About the Author
Daniela Bruse is the Founder of BRUSEGROUP and a Strategic Advisor to climate technology companies. She advises organisations on urban climate adaptation, urban forestry, digital infrastructure and strategic communications, helping them translate complex technical expertise into thought leadership that supports business growth and industry influence.
Her writing explores how cities can become more resilient by combining long-term planning with better operational decision-making, data and emerging technologies.