Why the Twenty-First Century Has Made the World Look at Urban Trees in an Entirely New Light
Only a few decades ago, trees were regarded primarily as elements of urban landscaping and street decoration. Today, the situation has changed fundamentally. In many countries across the world, green plantings are now considered fully-fledged green infrastructure, and the costs of establishing and maintaining them are treated as investments in urban resilience, public health, and climate adaptation.
In 2025, the United States Environmental Protection Agency (EPA) published its Green Infrastructure Strategy to 2035, which emphasises that natural systems must be planned on an equal footing with roads and engineering networks.
According to the document, green infrastructure delivers reductions in urban temperatures, stormwater management, improvements in air quality, the preservation of biodiversity, and the enhancement of urban resilience.
Source: Tech NaujienosIf the Trees Were Removed
Imagine a modern city without trees. In summer, asphalt heats up to 60–70 °C, building rooftops reach 80 °C, and concrete surfaces continue to radiate heat well into the night. The air grows drier, concentrations of dust increase, electricity consumption for air conditioning rises sharply, and the wellbeing of residents deteriorates.
At first glance, it might seem that the only solution to these problems lies in the construction of new engineering structures. Yet nature has long since devised a far more effective system. A single mature tree simultaneously cools the air, purifies it, intercepts rainwater, reduces noise levels, shields buildings from overheating, and absorbs carbon dioxide. This is precisely why specialists increasingly refer to trees as living infrastructure.
The Tree as a Natural Air Conditioner
A tree's principal function extends well beyond the provision of shade. Its primary cooling effect is generated through transpiration — the evaporation of water through the leaves. A mature tree is capable of evaporating hundreds of litres of water each day. According to numerous studies, air temperatures in well-planted districts are typically 2–8 °C lower than in densely built-up areas, while surface temperatures beneath a tree's canopy can be as much as 20–45 °C cooler than scorched asphalt. It is for this reason that parks and tree-lined avenues become natural "islands of coolness" within the city.
It is equally important to understand that not every tree performs the functions of green infrastructure with the same degree of effectiveness. In hot climates, species with large, spreading crowns that cast broad natural shade are of particular value. It is precisely these trees that are capable of significantly reducing temperatures across pedestrian spaces, building façades, and road surfaces.
These include plane trees (Oriental plane), elm, ash, lime, oak, maple, and certain other deciduous species adapted to local conditions. By contrast, coniferous trees with narrow crowns — such as most spruces or thujas — serve a predominantly decorative function and provide virtually none of the shading coverage that urban streets and squares require.
This is precisely why, when developing greening programmes, it is important to evaluate trees not only for their ornamental qualities, but also for their capacity to create a comfortable microclimate, reduce the urban heat effect, and fulfil infrastructural functions.
Trees in Place of Costly Engineering Structures
Consider a heavy summer downpour. The summer of 2026 illustrated this scenario to Tashkent in no uncertain terms. In a modern city, water rushes swiftly across asphalt into the stormwater drainage system. When that system is overwhelmed, the streets flood. Now picture the same street lined with trees. The raindrops are first intercepted by the leaves. A portion of the moisture evaporates back into the atmosphere. The remainder gradually flows down to the trunk and is absorbed by the soil, where it is retained by an extensive root system. As a result, the volume of surface run-off is significantly reduced.
This is why modern cities are increasingly turning to trees, rain gardens, and other elements of green infrastructure as a complement to conventional stormwater drainage. In the EPA strategy, green infrastructure is regarded as a vital instrument for stormwater management, localised flood prevention, and the replenishment of groundwater reserves.
Trees Save the City Money
It is widely assumed that maintaining urban trees is an expensive undertaking. Yet global experience suggests the opposite. It is precisely the absence of green plantings that leads to considerably greater economic losses.
The overheating of streets increases expenditure on building air conditioning, accelerates the deterioration of road surfaces, places greater strain on electricity networks, and contributes to rising healthcare costs. Conversely, by shading building façades, trees reduce their heat absorption and allow for a substantial reduction in electricity consumption during the summer months.
International research indicates that the thoughtful placement of trees around buildings can reduce air-conditioning costs by 20–40%, whilst simultaneously lowering ambient urban temperatures and peak demand on the energy grid.
The City's Air Filter
Every leaf of a tree functions as a miniature natural filter. Road dust, soot particles, heavy metals, and fine particulate matter — PM₂.₅ and PM₁₀ — settle on its surface daily. In addition, trees absorb carbon dioxide, nitrogen oxides, and other pollutants.
This is precisely why streets with well-developed tree cover are distinguished by cleaner air and a more favourable microclimate. The EPA counts improvements in air quality among the key benefits of green infrastructure, alongside temperature reduction and the restoration of natural ecosystems.
The World Is Already Changing Its Approach
In recent years, the approach to urban greening has changed fundamentally. In many countries, green infrastructure is now planned alongside roads, buildings, and utility networks. This approach is already being applied in Singapore, Copenhagen, Melbourne, Amsterdam, Vancouver, and other cities. In the United States, the development of green infrastructure is supported at the federal level.
Each year, substantial funds are allocated through the programmes of the United States Environmental Protection Agency to implement green infrastructure projects, develop methodological guidelines, conduct scientific research, and provide technical support to municipalities.
As a result, green infrastructure has become an integral part of water resource management programmes, climate change adaptation strategies, and sustainable urban development initiatives.
What does this mean for Uzbekistan?
For Uzbekistan, the development of green infrastructure is becoming a matter of strategic importance. Summer temperatures in many cities regularly exceed 40 °C, and on certain days the surface of asphalt heats up considerably further. Meanwhile, urban populations continue to grow, built-up areas are expanding, and the amount of available natural open space is diminishing.
In these conditions, every mature tree becomes an element of a city's climate defence. Greening can therefore no longer be regarded as the final stage of urban improvement. It must be planned in tandem with roads, utility networks, and public spaces.
In lieu of a conclusion
The twenty-first century has transformed our very understanding of urban infrastructure. Today, trees are no longer merely ornamental features of the city. They constitute fully-fledged infrastructure, performing the functions of a natural air-conditioning system, an air purification network, a stormwater management mechanism, a noise barrier, and a carbon sink. Unlike most engineered structures, a tree simultaneously addresses several challenges at once, rendering the city more resilient, safer, and more liveable.
It is precisely for this reason that the modern city must treat its trees with the same care it affords to roads, bridges, and utility networks. After all, a mature tree can be destroyed in a matter of minutes, whereas restoring its infrastructural value may take several decades.
