Why Trees Matter

Urban trees are not just a beautiful addition to our cityscape; they are a vital component of a healthy and sustainable environment. Modern cities recognize this and strive to make green spaces accessible to all citizens. A widely recognized urban planning guideline, the "3-30-300 rule," states that every citizen should be able to see at least three trees from their home, live in a neighborhood with 30% tree canopy cover, and be within 300 meters of a park or green space. This document outlines the key benefits that make such access essential for the residents of Yerevan.

1. Shade and Cooling in a Hot Climate

Yerevan's climate is characterized by hot, dry summers, making urban trees and the shade they provide essential for the comfort of all residents. By creating cooler microclimates, trees make public spaces like parks and sidewalks more pleasant and usable during the hottest parts of the day.

This need for shade extends beyond pedestrian walkways and into the streets themselves. Asphalt roads can absorb solar radiation and heat up to an astonishing 60 degrees Celsius in summer. This turns our streets into giant "hot pans" that radiate intense heat, making the surrounding environment unbearable even if the sidewalks are shaded. To combat this, we need large trees with canopies that can extend over the roads, providing comprehensive shade that cools the entire urban corridor.

Ultimately, this is not just a matter of comfort but of public health. Extreme heat is a significant health risk, and urban trees are a key defense. Studies have shown a direct link between the loss of urban tree canopy and an increase in mortality rates. For instance, research in the United States on the impact of the emerald ash borer—an insect that killed millions of trees—found a significant increase in deaths related to cardiovascular and lower-respiratory issues in areas that lost their tree cover.

2. Cleaner Air for a Healthier City

Trees are natural air purifiers, and in Yerevan, they are our primary defense against severe air pollution. Our city faces unique challenges: the Nubarashen landfill often burns, releasing toxic smoke; many vehicles lack catalytic converters, pumping pollutants directly into the air; and Yerevan's geographic position in a valley often leads to thermal inversions, where a layer of warm air traps colder, polluted air close to the ground, allowing pollution to accumulate to dangerous levels.

In this context, trees are not just beneficial; they are essential. They absorb harmful pollutants, with a particular focus on particulate matter (PM2.5), which poses significant risks to respiratory and cardiovascular health. The effectiveness of this filtration is directly related to the size of the tree. A large, mature tree has a vast leaf surface area, which can capture significantly more PM2.5 particles than a small, young tree.

This is why replacing a single large tree with two or even more smaller saplings, while a potentially good long-term strategy, is a disaster in the short term. We lose immediate, high-impact air filtration when we need it most. This highlights the urgent need for alternative approaches that prioritize the preservation of our existing large trees while we expand our urban canopy.

3. Psychological Well-being and Mental Health

The presence of trees and green spaces has a demonstrable positive impact on our mental health. This is not something you have to be a "tree lover" to experience; the effect is often unconscious and automatic. Scientific research shows that simply being around trees—even seeing them from a window—reduces stress, improves mood, and restores mental focus. This happens on a subconscious level. Our brains are wired to respond positively to natural environments. In a bustling city like Yerevan, these green oases are essential for our psychological well-being, providing a silent, constant source of mental relief.

4. Noise Reduction for a More Peaceful Environment

Urban noise pollution is a constant source of stress and can have long-term health consequences. Trees can significantly reduce noise levels. Studies have shown that a well-designed tree belt can reduce noise by 5 to 10 decibels, which is perceived by the human ear as a halving of the sound. The leaves, branches, and trunks of trees absorb and deflect sound waves, creating a more peaceful and pleasant environment.

5. Energy Savings for Buildings

Trees provide natural cooling for buildings, reducing the need for air conditioning during the hot summer months. This translates directly into lower energy bills for residents and businesses. Beyond individual savings, this reduced demand also significantly lessens the load on the city's power network, preventing overloads and reducing the frequency of power failures, particularly during periods of peak electricity consumption in extreme heat. By strategically planting trees around buildings, we can create a more energy-efficient and sustainable city.

6. Stormwater Management and Water Purification

Trees are excellent at managing stormwater. Their canopies intercept a significant amount of rainfall, which reduces the volume of water rushing into our drainage systems and helps prevent flooding. Furthermore, their root systems filter pollutants from the water as it seeps into the ground, improving water quality and recharging our groundwater reserves. This provides a natural and cost-effective addition to our city's infrastructure.

7. Economic and Commercial Growth

A green city is a prosperous city. Studies consistently show that properties in neighborhoods with a healthy tree canopy have higher market values. Additionally, tree-lined commercial districts are more attractive to shoppers, who tend to stay longer and spend more money, thus boosting the local economy. A beautiful urban environment also helps attract tourism and new business investment.

8. Community Building

Trees and the green spaces they create are the bedrock of strong communities. They provide beautiful, neutral ground where residents can connect. Parks, squares, and even simple tree-lined benches serve as natural gathering places that foster spontaneous social interactions, helping neighbors to meet and build relationships. These spaces are also vital for children, offering safe environments for play, which is essential for their social development.

Furthermore, public green spaces are among the most democratic areas in a city, accessible to everyone regardless of age or background. They can host community events like festivals and markets, bringing people together with a common purpose and creating a shared sense of local identity and pride. By strengthening the social fabric of our neighborhoods, urban trees make our city a more connected and supportive place to live.

9. UV Radiation Protection

The shade from trees does more than just cool us down; it also protects us. A dense tree canopy can block a significant amount of the sun's harmful ultraviolet (UV) radiation, reducing the risk of skin damage for pedestrians, especially children.

10. Biodiversity

Urban trees are not just for humans. They provide habitat and food for a variety of wildlife, including birds and insects. This biodiversity is a sign of a healthy ecosystem and contributes to the overall resilience of our city. In a healthy, biodiverse ecosystem, individual trees are stronger, more resilient to disease and pests, and generally healthier. This means they require less intervention and maintenance, allowing the city to spend less money on tree management while achieving better results for the urban forest as a whole. Promoting a diverse range of native tree species can help to create a more vibrant and ecologically balanced urban environment.