Environmental Impact Assessment: Holding back the sea, one tree at a time

Wed, Nov 11, 2020 page13

Environmental Impact Assessment: Holding back the sea, one tree at a time

A foundation is afforesting Taiwan’s coastline in an attempt to mitigate the effects of climate change
- By Steven Crook / Contributing reporter
Sometimes, Cheng Li-yi (程禮怡) feels like she’s fighting a losing battle.
“Because planting trees along the coast is so difficult, the area we can reforest each year is small. However, the area of coastal forest annually destroyed by development and other causes is significant,” she says. “Without forests to protect our coasts, the ocean’s impact on Taiwan will be greater, and dry land will quickly disappear due to rising sea levels and land subsidence,” says Cheng, director of Tse-Xin Organic Agriculture Foundation’s (TOAF, 慈心有機農業發展基金會; toaf.org.tw) reforestation initiative.
Since 2015, volunteers organized by TOAF, which promotes organic agriculture, environment conservation, tree-planting and plastic-free action, have created or regenerated windbreak forests in 23 districts and townships on Taiwan’s north, west and east coasts, planting a total of 518,515 trees on 260 hectares of land.

TOAF volunteers plant saplings in Dayuan District, Taoyuan City.

Photo courtesy of TOAF

Hoping to mitigate climate change, TOAF started planting trees in 2010. Just as the foundation began to run out of privately-owned plots on which it could nurture woodlands, Cheng realized that the forests that once characterized much of the west coast had been massively fragmented.
Deng Shu-lin (鄧書麟), chief of the Taiwan Forestry Research Institute’s Chungpu Research Center, expresses the decline of coastal forests in stark numbers. The total area of such woodlands shrank from 17,747 hectares in 1985 to 13,742 hectares last year, he says.

On May 10, the Chinese-language United Daily News reported that, in addition to rising sea levels, the removal of sand for use by the construction industry and the building of reservoirs inland (which reduces the amount of sediment reaching the sea) have undermined coastal woodlands.

The site of TOAF’s first coastal reforestation project in Yunlin County’s Taisih Township, caked with salt in 2015.

Photo courtesy of TOAF

Windbreak forests are especially important to Taiwan.
“Our coastal areas are often hit by monsoons and typhoons,” Deng says. “Therefore, coastal windbreaks are very important to the stability of shifting sand, to crop production and to protecting the living environment in coastal areas.”
People who live in the part of Yunlin County that faces the Taiwan Strait understand the link between coastal forests and a pleasant environment. They’ve long been afflicted by gritty air and clouds of dust. In Sihhu Township (四湖), there’s even a place that, since the Qing era, has been called Feisha (飛沙, “flying sand”).

The site of TOAF’s first coastal reforestation project in Yunlin County’s Taisi Township, as it looked last year.

Photo courtesy of TOAF

Due to Taiwan’s location, the country is particularly susceptible to environmental changes, Deng says.
“As a response to climate change, afforestation and reforestation are the most cost-effective ways to reduce net carbon emissions. Windbreak forests also have this function,” he adds.
Most people understand that trees sequester carbon, and how coastal forests can blunt gale-force winds blowing in from the ocean. But, Deng says, not many are aware that clusters of trees can also: dilute or absorb manmade pollution; improve the micro-environmental climate within those forests; and, by holding back sand and seawater droplets, protect nearby crops.

Cheng Li-yi, second from left, with TOAF colleagues at a tree-planting site in New Taipei’s Jinshan District.

Photo courtesy of TOAF

In Japan, such woodlands are known as coastal disaster-prevention forests, because they provide some protection against tsunamis.
The case for preserving and even expanding forest cover close to the shore is easy to make. Getting trees to grow in such challenging conditions is a different matter.
In 2015, in cooperation with the county government, TOAF adopted a piece of land in Yunlin County’s Taisih Township (台西).
“The land was already 2m below sea level before we began planting. Seawater would flood in, and the soil was heavily saline. Initially, we wanted to bring soil dredged from reservoirs to the site, to raise the ground ahead of tree-planting. Unfortunately, this turned out to be too expensive,” Cheng says.
The reforestation team began digging and piling soil, but when they disturbed a fiddler-crab habitat, they ran into opposition from local conservationists. After consulting experts, TOAF agreed to shift their tree-planting effort to a less ecologically-sensitive plot.
At the new site, the foundation created a four-hectare artificial wetland to retain rainwater. “It’s the only source of freshwater in the vicinity, and it desalinates the topsoil and subsoil. We then planted about 60,000 trees around the wetland, of which 70 percent have survived. Where only weeds and grass used to grow, there’s now a thriving woodland,” Cheng says.
An important breakthrough was made in 2017, when TOAF began using water-storing tree planters developed in conjunction with Taipei-based social enterprise Zen Zhou Co (仁舟社會) and made of recycled paper.
Devising a tree planter that was waterproof and would last at least six months, yet would ultimately decompose, wasn’t easy. Yet the results have been impressive: According to Cheng, using the planters has lifted the survival rate of saplings to over 90 percent, and doubled the speed at which they initially grow. Each planter has space for two saplings.
At the majority of sites, a necessary preliminary step is the building of fences to protect saplings from wind damage. Volunteers sometimes erect simple bamboo perches to attract eagles, because the rodents which often damage young trees by chewing their bark will stay away if they see a bird of prey. After planting, volunteers monitor rainfall; if necessary, they’ll water the trees and shrubs.
Few tree species flourish in proximity to the ocean. To survive and function as windbreaks, trees should grow fast and develop deep roots. Many are evergreens, but deciduous trees are better able to intercept flying sand. Tolerance to salt and strong winds is essential. In the south, where it often goes a month or two without rain, drought tolerance is a useful characteristic.
One species often planted in the past was Casuarina equisetifolia. Also known as the whistling pine tree, it’s been deployed as a windbreak and sand blocker since it was introduced to Taiwan in 1897. However, because of its vulnerability to pests and diseases, few Casuarina equisetifolia survive more than 30 years. Mature specimens are tough, and sometimes exceed 25m in height. The survival rate of seedlings near the shoreline is so low, however, that repeated reforesting is necessary.
TOAF prefers native species, such as Hibiscus tiliaceus and Scaevola taccada, Cheng says. The latter is also known as beach cabbage. Pandanus tectorius (the thatch screwpine) seldom grows more than 3m high, but it’s extremely robust, and can survive even when mostly covered by sand.
The foundation also plants some nectar-yielding plants and fruit trees, such as Elaeagnus oldhamii (the yiwu), Pittosporum pentandrum (the fragrant pittosporum) and Pyracantha koidzumii (the Taitung or Formosa firethorn) to provide food for small animals.
On social media, TOAF has shared night-camera images of wild hares spotted in a coastal forest in Taichung, as well as stunning data on the cooling effect of tree cover. In July, noontime temperatures of 40 degrees Celsius were recorded in one windbreak. A few meters away, sandy topsoil exposed to the sun was a blistering 85 degrees Celsius.
Since 2017, TOAF’s coastal afforestation work has attracted sponsorship from 31 companies — and an aphorism shared by Buddhist Master Shin Jih-chang (日常老和尚), the late founder of the Bliss and Wisdom Foundation of Culture and Education, helps Cheng stay motivated: “If this is supposed to be done and no one is doing it, then let’s do it.”
Steven Crook, the author or co-author of four books about Taiwan, has been following environmental issues since he arrived in the country in 1991. He drives a hybrid and carries his own chopsticks.
Comments will be moderated. Keep comments relevant to the article. Remarks containing abusive and obscene language, personal attacks of any kind or promotion will be removed and the user banned. Final decision will be at the discretion of the Taipei Times.
Most Popular