The Importance of Shade Trees
(Published in the newspaper Amigoe on the 25th of March 2026)
In the previous article, we discussed rising temperatures, a longer hot season and higher night temperatures due to climate change. We also discussed the health effects of this. We have also seen which population groups suffer the most from this. In this article, we will discuss how shade trees reduce temperature. We will also discuss the many advantages of shade trees compared to other ways to lower the temperature.
Anyone who walks through the city on Curaçao will notice it immediately: in many streets and squares there are few or no shade trees at all. In the city center, around schools and in residential areas, you often walk from one sunny spot to another, without natural cooling. Asphalt, concrete and stone facades absorb a lot of heat during the day and slowly release it again, keeping the environment extra hot, even later in the day and at night.
Well thought-out urban planning, and sensible construction methods, could have mitigated many heat problems from the outset. By taking into account natural ventilation, shadow structures and a smart orientation of buildings when building, the heat build-up in the city could have been lower. Unfortunately, not enough attention has always been paid to this in practice. As a result, we are now faced with the challenge of reducing urban heat with additional measures. Planting shade trees is an effective strategy for this.
How do shade trees lower temperature?
Shade trees have a clear cooling effect on Curaçao that is based on two important mechanisms. Firstly, the shade of trees blocks direct solar radiation on the skin. As a result, the perceived temperature in the shade of trees is considerably lower than in full sun. This is especially important in Curaçao's tropical climate, where sun strength is high year-round and exposure to direct sunlight can quickly lead to heat stress.
Secondly, trees actively reduce the air temperature because the leaves evaporate water. This is also called evapotranspiration. Water that evaporates through the leaves extracts heat from the surrounding air and thus creates a cooling effect. This process can be compared to the refreshing sensation of a menthol-containing body splash such as alcolado glacial. The evaporation of the alcolado glacial applied to the skin cools the skin. In urban environments with a warm and dry climate, measurements show that the air temperature under a mature, well-leafed tree can be on average 1 to 3 °C lower than in direct sunlight.
Due to the combination of a lower perceived temperature because of shade, and a lower air temperature due to evaporation, the decrease in the total perceived temperature under a tree is 5 °C or more. As a result, shade trees contribute greatly to a more comfortable and healthier outdoor climate. What are the advantages of shade trees compared to other methods of combating heat?
Lower energy consumption and lower energy costs
Cooling by shade trees means that the need for artificial cooling decreases. Less use of air conditioning means lower electricity consumption and therefore lower energy costs. In addition, it reduces the load on the electricity grid and the greenhouse gas emissions associated with energy generation. On an island like Curaçao, where a lot of energy is used for cooling, shade trees can therefore be a simple and sustainable way to reduce energy consumption. By combining natural shade and cooling, trees contribute to a more comfortable indoor climate and lower energy costs for schools, homes and other buildings.
More pleasant microclimate on the street or in the schoolyard
Measures such as white roofs or reflective paint can help to prevent buildings from getting hot quickly. However, they have less effect on the temperature at street level where people are. Shade trees do have that effect. They not only lower the temperature of the surrounding air but also create air circulation. This creates a more pleasant microclimate in streets, squares and around buildings where people are.
Cooling larger areas
An important advantage of shade trees is that they can cool a larger area at the same time. The shadow of a tree covers sidewalks, roads, parking lots, and facades, so that they absorb less heat and release less heat back into the environment. This makes the public space more comfortable. This is especially important in a sunny and warm climate such as that of Curaçao, where many activities take place outdoors.
Shade trees in a shopping street
Cooler classrooms and schoolyards
Shade trees are extra valuable for schools. Not all classrooms have air conditioning, so the temperature inside can rise quickly. Trees around school buildings can keep classrooms cooler by shading walls and roofs, reducing the need for air conditioning. Even in schoolyards, where students often stand in full sun during breaks or sports activities, shade from trees can make a difference. Shaded playgrounds provide less heat stress, a lower risk of overheating, and a more comfortable environment for playing and learning. This contributes to the health, concentration and well-being of students and teachers.
Shadow in the schoolyard
Additional benefits of trees
In addition to cooling, trees offer other advantages. For example, trees improve air quality. Through photosynthesis, trees absorb carbon dioxide (CO₂) and convert it into oxygen, helping to reduce greenhouse gases. In addition, trees filter harmful substances such as particulate matter (PM10 and PM2.5), nitrogen dioxide (NO₂) and ozone from the air. Furthermore, trees reduce noise pollution. Among other things, they absorb part of the sound waves. Trees can also help rainwater to infiltrate the soil better. Trees also contribute to local biodiversity. This is because they provide food and shelter for native birds, insects, and other species, making urban ecosystems more resilient. Unlike air conditioning, trees do not use energy and do not move heat outside. They cool passively and sustainably.
Why native trees?
Native trees are generally better suited to the urban environment of Curaçao than exotic species. Native trees have evolved under the local conditions of heat, drought, strong winds, and salty air. As a result, they have more efficient root systems and leaves that cope better with intense sun and limited precipitation. They require less irrigation and maintenance. In addition, native species often provide more effective shade and cooling because they are tailored to the local climate and are more resistant to prolonged heat waves. They are also less susceptible to disease.
Some examples of trees that are suitable for the urban environment are:
- Wayaka Guaiacum officinale), called "pokhout" in Dutch
- Black Olive (Bucida buceras)
- Mangel Blanku (Conocarpus erectus), in Dutch "knoopmangrove", and in English called "buttonwood"
- Mahòk (Swietenia mahagoni), in Dutch called "West Indian Mahogany
- Dreifi di Laman (Coccoloba uvivera), called sea grape in Dutch
- Dividivi (Caesalpinia coriaria), also called Watapana in Papiamento
Exotic trees can grow quickly at first and provide a lot of shade but often need more water and are more susceptible to diseases, storm damage and prolonged drought. When such trees weaken or die, the cooling effect is lost, and they must be replaced. This leads to extra costs and extra heat build-up in the city. Native trees are therefore often a better choice.
In short, planting shade trees in the city is of great importance to keep the city livable for the local population now and in the future. This is even more important for vulnerable groups that are already suffering greatly from the heat, such as the elderly, schoolchildren and people with a lower income. A cooler city is also essential for tourists. They also experience nuisance from high temperatures when visiting outdoor tourist attractions. There are also relatively many elderly people among tourists, for whom this is even more important. A cooler city therefore not only provides health benefits but also creates clear economic added value.
In the following article, we will give tips on how to plant shade trees in the city. In the city, you must consider issues such as limited growing space, paving, heat, water availability and use of public space.
The Importance of Shade Trees