Trees for healthier cities

January 24, 2020 | By: Architect Felino A. Palafox, Jr. (first published in The Manila Times last January 23, 2020)

‘Trees can live without people, but people cannot live without trees.’

ACCORDING to scientists, planting billions of trees around the world can make a big impact in cleaning the world’s overwhelming carbon emissions and help combat climate change. Researchers at ETH Zürich have identified planting trees as our best and cheapest solution to fight climate change. Their recent analysis reports that 1.2 trillion native tree saplings can grow in 1.7-billion hectares of treeless areas. In fact, planting forests the size of the United States can reduce atmospheric carbon dioxide by 25 percent. Aside from absorbing carbon dioxide, trees can also retain other urban pollutants like nitrous oxide, industrial soot and heavy metals, among others, which are stored in the wood. The older the trees are, the more effective they are in controlling pollutants. Sadly, last year and until now, deadly wildfires have laid waste millions of hectares of rainforests, bushland and national parks — densely vegetated areas that are the earth’s carbon sinks. In the Amazon, approximately 1,812,992 hectares of rainforests were destroyed, while in Australia, more than 4,870,391 hectares have already been razed — further elevating greenhouse gas emissions. Worse, it will take years before these trees are replaced and can be mature enough to absorb atmospheric carbon and other pollutants. Nevertheless, experts have calculated and ranked certain regions where it will be least risky and costly to reforest. They discovered that the best locations to reforest are in more than 100 million hectares of tropical rainforests spread across Africa, Southeast Asia, and Central and South America.

In 2015, the World Economic Forum (WEF) included enhancing green canopy cover at the top 10 urban initiatives that cities must prioritize. As a result, tree-planting programs have become an important component of urban planning because these promote resiliency, sustainability, health, wellness and economic success, among others. The manifold benefits of urban trees should hinder local governments and developers from cutting down trees to make more space for infrastructure and other kinds of development. Trees can alleviate some of the negative effects of urbanization and can help cities become more resilient and sustainable. Extensive tree cover in the city can reduce urban heat island temperatures of between 2 degree Celsius and 8 C by increasing water evaporation and blocking shortwave radiation. A mature tree can absorb up to 150 kilogram of carbon dioxide each year and can filter fine particulates and other urban pollutants, thus improving air quality. Trees are valuable components of stormwater management because a single tree can retain more than 100 gallons of rainfall, and collectively, trees help collect and filter water to be channeled to aquifers and watersheds that replenish our groundwater supply. Trees increase food security by providing fruits, leaves and nuts for consumption, and they boost urban biodiversity by giving animals and other plants more favorable and safe habitats. Living near urban green spaces has numerous physical and mental health benefits such as increased physical activity and reduced stress and blood pressure. Trees around buildings can help conserve energy, reducing the need for air conditioning by 30 percent and winter heating by 20 to 50 percent. In addition, green urban spaces can increase property value by 20 percent and attract more opportunities for business and tourism.

Thankfully, more cities are heeding the call for urgent and large-scale reforestation. Treepedia, a collaboration between the Massachusetts Institute of Technology and the WEF, measures the tree cover of 27 cities through their Green View Index — a metric that assesses and compares tree canopy density. Tampa City in Florida is No. 1 on the list, with 36.1 percent of its area as tree cover, which is more than one-third of the city. It is followed by Singapore with 29.3 percent, Oslo with 28.8 percent, and Sydney and Vancouver with 25.9 percent.

It took decades for Singapore to replace its reputation as an overly polluted city with its current international renown as a “city in a garden.” It started with Lee Kuan Yew who was fondly called “Chief Gardener” because of his belief in the ability of biodiversity and plants to increase people’s and spaces’ well-being. Singapore has since flourished and become a model for environmentalism and sustainability by establishing urban plans that promote the creation of world-class gardens and nature reserves, revitalization of urban parks and streetscapes, construction of green infrastructure, strengthening of their landscape and horticultural industry, and community engagement.

Oslo is Europe’s Green Capital for 2019. Its sustainable city planning, which is the result of a collaborative effort of the local government, urban planners, businesses and communities, includes emission-free mobility, energy-efficient neighborhoods, waste-to-energy initiatives, habitat conservation and, of course, expansion of green areas in the city. School gardens are a tradition in Oslo, and early on, local children learn firsthand the joys of urban farming. Additionally, the city has allotted 1,000 gardens that are part of garden colonies in which families or individuals can plant vegetables, fruit trees and other plants. Similarly, Sydney is hoping to plant 5 million trees by 2030 through the city initiative “Five Million Trees,” which will increase their urban tree canopy from 16 percent to 40 percent. The local government allotted $38.7 million for this project. Trees will be planted in schools, parks, backyards and streets — creating a more livable and healthier city.

Today, intensifying reforestation and urban tree planting initiatives have never been more crucial. If you look at it, trees take care of us; the numerous benefits we get from trees are invaluable. So, shouldn’t we, in the same way, value and take care of them more?



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