Increasing tree numbers in urban environments is a global priority but for city trees to flourish, they need effective protection systems like Wavin TreeTank.
As cities worldwide expand, balancing urban development with green infrastructure is essential. Trees are central to this greenification movement due to the wide range of benefits they deliver. From a sustainability perspective, they’re crucial to carbon capture and lowering the risk of urban flooding by reducing surface runoff. Beyond this, trees enhance urban residents’ quality of life by contributing to air purification, helping cool cities in hot seasons, fostering community well-being, and promoting better mental and physical health.
Despite increasing urbanization, national and local governments understand the importance of increasing tree numbers in urban environments. A significant positive is that municipalities globally are taking action to boost greenification, ensuring the future for urban tree expansion initiatives looks bright.
Enhancing greenification, one city at a time
Cities around the world are embedding long-term investment into tree-planting programs inspired by the United Nations’ Trees in Cities Challenge. This initiative encourages cities to commit to planting and maintaining trees as part of their climate action and urban sustainability efforts. As of August 2024, the Challenge has facilitated the planting of 18.5 million trees globally, surpassing its initial target by more than double.
Although the structure of these tree-planting programs varies from city to city, they all aim to enhance sustainability, increase biodiversity, improve environmental quality and foster closer connections between residents and nature, as a few examples demonstrate…
In Barcelona, the Tree Master Plan intends to increase the city’s urban forest over two decades to cover 30% of the city’s surface area by 2037, representing a 5% increase. London also aims to increase tree cover to 30% by 2050. The London Urban Forest Plan sponsors community urban greening initiatives, focusing on areas with high air pollution and low biodiversity. Over in New York, the MillionTreesNYC initiative aimed to plant one million trees across its five boroughs and achieved its goal two years ahead of schedule. Indian cities like Mumbai, Bangalore and Chennai create dense, fast-growing micro-forests in vacant urban spaces. Melbourne focuses on mitigating extreme heat with an Urban Forest Strategy to double its urban tree canopy cover from 22% to 40% by 2040, relying primarily on tree species resilient to climate change. China’s Sponge Cities Program tackles city flooding with large-scale urban tree planting and eco-friendly drainage systems to improve water management and enhance urban resilience. While, in Mexico City, the Green Challenge revegetation strategy planted 10 million trees and other plants between 2019 and 2020.
However, these ambitious initiatives only work if the trees they plant thrive. It’s not enough to achieve tree planting targets—long-term tree survival is vital. To ensure this, municipal governments and those running tree-planting projects must consider and mitigate the urban factors that can threaten tree survival.
Maximizing tree health in urban environments
Although trees have simple needs for optimum growth and longevity, urban environments can struggle to provide what the countryside delivers more naturally. Broadly, trees require enough room for their roots to spread out and anchor securely in loose soil for better nutrient, mineral and water absorption. Crucially, trees require oxygen, and well-aerated soil ensures oxygen reaches their roots.
Unfortunately, urban areas often have soil that’s compacted or lacks oxygen, forcing tree roots to spread horizontally to find the nutrients, oxygen and water they need rather than penetrating deeper into the ground. Roots often extend up to three times the tree’s canopy width, making them a common cause of city infrastructure damage. They can lift pavements, crack road surfaces and interfere with underground utilities, leading to damage and costly, disruptive repairs.
Tree protection systems support urban green assets
Fortunately, by implementing measures such as tree protection systems, cities can reduce infrastructure damage and extend the lifespan of roads, sidewalks and underground services, ultimately improving urban resilience.
Tree protection systems that include root barriers help mitigate tree-related damage by preventing roots from spreading horizontally and guiding root growth deeper into the soil. This provides enough space for trees to be well established without damaging the surrounding infrastructure. Installing root barriers is also a prime opportunity to tackle the soil compaction that restricts root growth. The resulting aerated soil enhances downward growth by giving roots the nutrients and oxygen essential for the tree to flourish.
Systems designed with load-bearing cells also help to prevent soil from compacting, protecting space for tree roots to grow while providing a stable foundation for pavements and minimizing surface damage. By incorporating flexible paving materials that expand with root growth, tree protection systems can also prevent cracking and reduce the need for frequent maintenance. Tree grates and sub-surface irrigation are valuable additions, increasing the flow of hydration and nutrients to trees.
Tree protection systems make financial sense
By investing in tree protection systems, municipalities can secure significant long-term cost savings and risk reduction for urban areas. Unprotected trees are far more likely to suffer from poor health, require frequent maintenance, or fail to thrive—ultimately needing to be removed and replaced—all scenarios which contribute to higher costs.
By helping trees to thrive, tree protection systems ensure that investment in trees ‘pays off’. And, by regulating root growth, they also reduce costly infrastructure repairs for damage uncontrolled tree roots can cause to sidewalks, roads and underground utilities.
Plus, promoting healthy tree growth mitigates liability risks caused by tree-related incidents, such as falling branches or cracked pavements, leading to injuries.
Meet the Wavin TreeTank: the modular system for optimum tree growth
To help urban trees flourish, Wavin (an Orbia company) manufactures the innovative Wavin TreeTank. This advanced underground water management system is designed to create optimal growing conditions for urban trees while safeguarding surrounding infrastructure.
Its modular structure of load-bearing cells provides a high-capacity water retention and distribution system, so trees receive sustained hydration without causing surface waterlogging. Wavin TreeTank’s permeable design promotes deep root growth, and its lightweight yet durable and long-lived construction supports soil aeration and load-bearing capacity.
The TreeTank creates safe underground protection zones for urban trees, ensuring healthy root growth while preventing soil compaction and enhancing stormwater management.
Discover how Wavin TreeTank can benefit your next project. Contact a Wavin Consultant today.
