Trees in need – closed



With more than a million trees, Amsterdam is one of the greenest cities in Europe. The trees aren’t just there for aesthetics – they’re also crucial to climate-proofing: they cool the air, take up rainwater and have a positive effect on wellbeing, health and biodiversity. On a hot day, one tree has the same cooling effect as ten air-conditioning units. Because trees are so valuable to Amsterdam and its inhabitants, they’re managed to keep them safe and healthy for as long as possible. 

Because of climate change, we are experiencing more extreme weather conditions, and this can drastically shorten the lives of assets like trees, bridges and canal sides. Asset management concentrates on maximising the lifespan of assets, and that also applies to trees. And so, Amsterdam is working to ensure that trees are future proof and that the city stays pleasant and liveable in a way that keeps the costs low. Various initiatives have already been launched, such as the Rainproof programme, aimed at coping with increasingly heavy rainfall. Drought is another topical climate issue: temperature and drought records were broken over and over again in 2018. We know that trees help to make the city heatproof, but how can we make the trees themselves heatproof?

During the drought in the summer months of 2018, the city districts spent €475,000 on watering plants and trees – around €160,000 a month. At a first rough estimate, because of the drought, the city has lost between 25 to 50 per cent of its planting (shrubs, perennials, hedges, new trees and lawns that are heavily used and are not watered, as in the Vondelpark and Sarphatipark). The cost of replanting next year is estimated at around €1.4 million euros. A more accurate estimate can only be made in spring when we see whether apparently lifeless plants start putting out new shoots. However, another period of drought or a hard winter could finish plants off. Apart from the initial expense of replanting, there will also be extra maintenance costs, because new planting needs more weeding and watering.

We’re looking for innovative solutions that enable the trees themselves to ‘express their needs’ so that ultimately we can provide customised care to individual trees. The aim is to enable trees to grow bigger and older, so they’re more attractive and more valuable to the city.


The Challenge:

Develop an innovative solution to enable trees to ‘express their needs’



  • We’re looking for a solution that will indicate and register exactly when a tree really needs water: ‘give the tree a voice’.
  • Circular solutions are preferred – for example, collecting rainwater during heavy showers to prevent flooding and using it to water trees during periods of drought.
  • Startups that at least have some knowledge of trees in an urban environment are preferred.
  • It should be possible to roll the solution out across the entire city, and it should be vandal proof.


  • Tree care in times of drought that is sustainable (no water wastage), efficient (targeted) and effective (amount of water per tree).
  • Circular tree management (water recycling).
  • Future-proof tree management (such as planting trees that are less sensitive to extreme weather conditions).
  • Data collection for risk management.
  • The tool must be affordable to use within the regular maintenance budget.
  • The City of Amsterdam aims to ensure that by 2025 all public space will have the status of ‘well maintained’. This means that at a given location, no more than 10 per cent of certain assets in public space may be classified below CROW standard B.


Issued by: Assetmanagement, Verkeer en Openbare Ruimte.


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