City in need of sturdier tree species after Hato
As Typhoon Hato reportedly damaged or uprooted as many as 10,000 trees, with over 4,000 of those needing to be destroyed, some experts have called for an immediate response in the form of planting trees before the autumn season.
Information from the Civic and Municipal Affairs Bureau (IACM) noted that around 70 to 80 percent of the trees were already treated by the department, and it has collected some 15,000 tons of broken tree branches.
Since most of the city’s trees were imported and not naturally grown inside the MSAR, the taproots of the trees are not as developed or deep when compared to trees that grew here from a seed. These inserted trees thus acquire more lateral roots than taproots.
Landscape architect António Saraiva suggested that the damages could be transformed into an opportunity to diversify tree species, as the city could choose certain species that will withstand typhoon weather conditions.
The agronomist proposed, in an interview with Ponto Final, that the planting of new trees should be conducted in a permeable floor area, not one blocked by cement and pavement, so that the roots can extend and provide more stability to the trees and resistance against strong gusts of wind.
According to him, replanting should start soon, as summer and spring are the best seasons for planting. He noted that there were several trees that were previously grown in vases, which can be transplanted into the needed locations.
Echoing the sentiments, Karen Tagulao, professor at the Institute of Science and Environment, told the Times that the region could choose trees with more complex root systems, similar to mangroves.
Tagulao explained that since mangroves have deeper roots on coastal areas compared to what is seen on the surface, the city should aim to plant more of such shrubs to assist the coastline of Macau.
“These shrubs are also efficient as a natural barrier against storm surge. So I really recommend to plant more mangroves to help the coastal line of Macau,” she said, adding that there are several coastal areas of Macau, particularly in the Inner Harbor area, which was one of the places most severely damaged by Typhoon Hato.
David Gonçalves, an associate professor at the University of Saint Joseph’s Institute of Science and Environment, said that trees provide a number of benefits in urban environments, including aesthetic, cultural, economic, environmental and climatic, as well as have an impact in reducing air, noise and water pollution.
“The destruction of a significant number of trees in Macau by Hato will certainly reduce some of these benefits,” he told the Times last night. “However, the extension of the impact will depend on a number of factors, like the proportion, size, location and types of trees that were destroyed, the restoration plan, among other factors. To properly predict the extent of the impact would [require] a deeper assessment of these factors.”
Regarding the typical practice of importing trees, Gonçalves said that it was a normal practice but city authorities ought to consider which regions the trees are being imported from.
“It is normal that young and recently implanted trees are more susceptible to be knock down by strong winds as their root system is less developed,” he said. “What should be assessed is whether the trees that have been planted in the urban environment of Macau throughout the years are the most appropriate to resist typhoons. Species native from typhoon areas are likely to be more resistant than species that have evolved in areas not subject to typhoons.”
Commenting on the impact of the damage to the city’s environment, Tagulao expressed her main concern: the region’s air quality. “Trees are natural filters so we really need trees to help the city’s air quality and pollution.”
Although these thousands of trees can still be replanted, the expert noted that growth recovery might take a lot longer.
Deforestation may increase risk of more disasters
The two typhoons to strike Macau last week have resulted in a partial deforestation of parts of the territory – most prominently in Coloane, after thousands of trees were felled – potentially increasing the threat of further environmental disasters.
The link between deforestation and natural disasters is well-documented.
In total, the Civic and Municipal Affairs Bureau estimates that as many as 10,000 trees may have been damage or uprooted by the two storms, with many of them in the hilly areas of Coloane.
Known as “vegetative cover”, trees in hilly areas play a vital role of water absorption during heavy rains and flooding scenarios. Heavy rains exert stress on soil particles that can create the conditions for landslides.
Deforestation has been damaged or used as a partial explanation behind successive landslides in the Philippines, India, Haiti and other countries.
David Gonçalves, an associate professor of environmental sciences, said yesterday that some studies show that proper plantation of trees can reduce the propensity for landslides by as much as 70 percent.
With thousands of damaged trees in the MSAR and around one-third of them being located in the hilly and sparsely populated areas of the territory’s south, any future rains during this typhoon season could lead to further natural disasters.
Karen Tagulao, professor at the Institute of Science and Environment told the Times yesterday that although much of the urbanized parts of the city are not at risk of landslides, there was some cause for concern in the hilly areas of Coloane and Taipa.
The Meteorological and Geophysical Bureau has warned through its website of a “low pressure system” over the northern Philippine island of Luzon that may develop into a tropical storm and enter the South China Sea.
Weather monitoring application Windy.com shows that a third typhoon, on a scale similar to Typhoon Pakhar, may form over the next few days and approach the Pearl River estuary by the early hours of Sunday morning. DB/LV
