URBAN TREES ARE A LOW COST OPTION TO MITIGATE THE CLIMATE CHANGE
A PROJECT BY THE DEPARTMENT OF FOREST SCIENCES SHOWED THIS IN THREE SECTORS OF TALCA, WHERE TEMPERATURE, RELATIVE HUMIDITY, PARTICULATE MATTER, NOISE AND UV RADIATION WERE ANALYZED.
March 04, 2016
Academics from the Department of Forest Sciences of our University created a well-being index that defines the most favored places in terms of the contribution of the urban trees for the mitigation of climate change.
This is one of the results of a project that studied for two years the influence of the city’s trees in the environmental variables of temperature, relative humidity, noise, particulate matter and UV radiation.
In general terms, the project —funded by the Environmental Protection Fund of the State Department of the Environment— endorsed the nowledge about the benefits of the urban forest in that aspect. In addition, it gathered useful information for decision making in the public sphere with regard to low-cost solutions in the cities, and especially in the areas of public use, following the idea of sustainable cities.
“Trees are not only aesthetic elements, but they also provides ecosystem services in the city and should be considered comprehensibly in urban planning,” said Professor Mauricio Ponce, researcher in charge of the project.
To study the environmental role of the urban forest in the mitigation of sources of pollution, Mauricio Ponce and Professor Óscar Vallejos —from the same Department— worked in three axes of the city of Talca: half of the Alameda park, the Diagonal in all its extension, and half of the Uno Sur street. These are places that present varying levels of traffic and trees coverage.
The academics carried out the measurements in three periods: November to January, April to May and September to November, in three time slots: morning, noon and evening, twice a week.
In total, they collected 1,968 records, the equivalent of 15,515 data items.
The researchers then linked the variables. Likewise, they constructed a well-being index (IB), as a result of the weighted sum of the factors, which they standardized because there were several magnitudes.
“With the weighted sum of these variables, this index was determined. Therefore, if the combination is positive, it means that there is more well-being associated to the conjugation of these variables. The largest was almost 2.3 which is the ideal situation that we were able to record, and there are situations that are in -1,3 associated with low tree coverage. A higher rate means that that sector has a higher well-being”, explained Óscar Vallejos.
According to the scientists, the real estate companies plant trees only to comply with the law in terms of percentage of green areas and trees, but it does not respond to a need for environmental improvements.
On the responsibility of the municipalities in this area, Ponce stated that they do a lot more than what it is thought “because they are responsible for the caring of all the trees.”
One of the responsible agencies, as indicated, is the Serviu, which approves the proposals of the construction companies. But it does so only to comply with the current regulations.
The researchers recommended to both the private and public sector, to consider the production of trees with certain characteristics, such as the type of foliage. This is due to their contribution to the ecosystem in the city and not just for their attractiveness.
In their study, the researchers detected an abundance of sweetgum, a “fashionable” tree, but that in the opinion of the experts is not very recommended, especially for sidewalks, because their roots are very superficial and requires a lot of water.
Vallejos pointed out that from the commercial point of view it is better to have wooded areas, because it is much more attractive to walk in these places than on streets without trees.
Among the findings made by the conductors of the project is the strong increase in the recording of ultraviolet radiation: one of the effects of climate change on which the woodland has a mitigation effect, as well as on high temperatures, noise, particulate matter and relative humidity.
One of the areas with the greatest benefit by the tree coverage are the places identified as heat islands, which as explained by Mauricio Ponce, they have very hard soils and buildings covered with windows, that generate reflection and heat radiation.
“Those places can have two or three more degrees of temperature compared to the areas with shadows”, he said.
In Talca, there is a heat island — according to this specialist— in a sector of the Uno Sur Street, in the area of the former Concentradas Schools.
Among the complementary activities of the project were the ones made together with the Prosperidad School in Talca, which attended the closing seminar, in the auditorium of the Department of Forest Sciences.
On this occasion, architect Fernando Montoya, from the School of Architecture, gave a presentation on Sustainable Cities. For his part, Professor Mauricio Ponce talked about the “state of the art “and methodology of the project. While academic Óscar Vallejos gave a presentation on the results obtained.
In addition, forest engineer Luis González, from the Municipality of Vitacura, talked about the “Management of the urban forest, a vision from the municipalities”.