A park in the Providencia commune, in Santiago (Chile), with just a handful of trees. NurPhoto (NurPhoto via Getty Images)
Santiago de Chile reached a maximum of 35.6 degrees this Thursday, but its seven million inhabitants do not deal with high temperatures in the same way.
How bearable the heat wave that will last for a week depends on whether the person is in a municipality with esplanades of trees or concrete.
The lack of green areas can raise temperatures by two to three degrees.
Of the 52 communes in the metropolitan region, only eight meet the minimum recommended by the World Health Organization: 10 square meters of green areas per inhabitant.
Most of them are concentrated in the wealthiest areas, where in some cases there are as many as 18. However, half of the territories, especially in the peripheral areas, where people with lower incomes tend to live, have surfaces below the five,
according to the system of urban development indicators and standards (SIEDU).
To deal with this inequity, the regional government has launched a plan to plant 30,000 native trees in the next two years, the kickoff of a project that aspires to 200,000 new plantations.
The "Urban Trees" program will plant an axis of 20 kilometers of trees in 34 municipalities with a deficit of green areas, which will benefit half a million inhabitants.
The Cultiva Corporation, dedicated to reforestation and environmental education, will have 2,000 million Chilean pesos (2.5 million dollars) to plant 11,000 trees in public spaces and deliver 19,000 to citizen organizations that will be trained in their proper care .
This Wednesday the architectural and urban planning team was formed that will be in charge of defining the benefited municipalities and the type of trees that will be used considering criteria of equity, heat waves and concentrated particulate matter, among others.
The Nueva Alameda-Providencia architectural and urban redesign project, which starts in the center of the city, is part of the urban tree-lined plan.
It begins in the municipality of Providencia, one of the most expensive to live in, and with 14.9 square meters of green areas per inhabitant, and continues its journey through the communes of Santiago, Estación Central and Lo Prado, one of the most arid areas. of the region, with 3.2 square meters of green areas per inhabitant.
Matías Herceg, executive director of Cultiva, clarifies that the plan will not necessarily go through all the aforementioned municipalities.
If a decade ago Chile suffered six heat waves a year, in 2022 they exceeded 60. Santiago in particular, being surrounded by hills, is a city that does not allow the emanation of gases to circulate fluently.
The importance of planting green lungs has the objective, in addition to offering shade to combat heat waves, to absorb particulate matter.
The first trees of the project will be seen from April, with the aim of ending this year with 10,000 to 15,000 new trees.
For now, Cultiva is considering planting quillay, huingán, quebracho, maitén and peumo.
Considering that the South American country has been going through a mega-drought for 14 years, the water needs of the plantations are key.
Herceg explains that it is crucial when choosing that they are native species with low water consumption.
There are areas where the water only arrives in cistern trucks once a week, for example.
“We are going to work with the municipalities to find out how much cost of irrigation they can assume, and if they have drinking water or can alter their water routes.
If support is necessary during the transition from the plantation to a solid tree, it will be supported from the Cultiva program or from the Regional Government”, points out the executive director of the NGO, who considers this problem a relevant point, but not critical.
The governor of the Metropolitan Region, Claudio Orrego, assured at the launch of the program that, due to the fact that heat waves hit the inhabitants of the most vulnerable communes more than the rest, they decided to plant 200,000 new native trees “where they are concentrated the heat islands.
The initial plan, in charge of Cultiva, addresses 30,000 new trees and will later continue with the 170,000 "through other lines," said Orrego.
In December, the authority announced on Duna radio that by 2024 100,000 new ones will have been planted.
This newspaper tried unsuccessfully to speak with the governor to find out the details of the macroproject.
The architect Francisco Schmidt, former adviser to the Ministry of Housing and Urban Planning, and manager of the Urban Parks Program, highlights the initiative, like other more local ones that have been made from plantations, but warns of the lack of maintenance that these have and that, added to water scarcity, end up in bare territories.
“It is one thing to plant, and another is to irrigate, control, administer, so that it bears fruit.
Especially if you think of native species, where many have slower growth," says Schmidt, who would like the figures for new trees to be more ambitious due to the climate emergency.
"Urban islands generate radiation that, when they announce 33 degrees, is actually 35. A call for very drastic and profound innovation must be made," says the architect.
Keeping the proportions, he looks at what has been done in Melbourne (Australia), where nature has been reincorporated into the city with the recovery of riverbeds, parks in between the city, rain gardens, porous pavements, among other initiatives.
For the specialist, the urban tree plan should focus first of all on the course of the Mapocho river and the streams that exist in Santiago.
A study published this Wednesday in
The Lancet
with data from 93 European cities (where 57 million inhabitants over the age of 20 live), cited in this article in EL PAÍS, found that close to 6,700 premature deaths are due to heat islands, a phenomenon where asphalt and concrete absorb heat during the day and emit it at night, raising the temperature compared to places where there are green areas.
The document concluded that a third of these deaths could be avoided by planting trees in 30% of urban space.