Love between Forest and Sea:

Over the past few years, the Penghu County Government has made a big push to plant trees and restore coral reefs, engaging in ecological revival that embraces their interconnectedness. It’s not wishful thinking to say that planting trees can protect fisheries. This is work that brings multiple benefits.

Rainforests of the sea

Known as “the tropical rainforests of the oceans,” coral reefs, which make up less than 1% of the world’s oceans by area, provide places for one-fourth of all marine fauna to breed, rear their young, escape predators and feed. They are critical for marine biodiversity. According to the Ocean Conservation Administration of Taiwan’s Ocean Affairs Council, more than 500 of the world’s approximately 1,500 coral species grow in Taiwanese waters. In South Penghu Marine National Park alone there are 209 species of coral, which belong to 54 genera in 15 families, according to a survey directed by Jeng Ming-shiou, a research fellow at the Biodiversity Research Center of the Academia Sinica.

But for more than ten years, climate change and harmful human activities have been decimating local coral populations. Ko Chih-hung, director of the ­Penghu County Marine Life Propagation Station, explains that tropical corals are suited to water temperatures of 20–28°C. Temperatures outside that range cause coral to bleach and die. When no typhoons hit Penghu for several years, water temperatures rose, leading to coral bleaching.

Conversely, says Chen Kao-liang, director-general of Penghu’s Agriculture and Fisheries Bureau, in 2008 the archipelago experienced a once-in-a-century cold spell, killing all but a tenth of its corals. A few years later, in 2014, the 360-square-kilometer South Penghu Marine National Park was established.

Coral cuttings are inserted into coral stone blocks and placed in ponds to grow for two weeks before being transplanted into the ocean.

The coral cultivation tanks designed by Ko Chih-hung provide a suitable environment for coral growth.

Artificial reefs

Broadly speaking, reef restoration work involves two stages: First, corals are cultivated on land; then they are transplanted to the sea.

At the Marine Life Propagation Station we examine a coral cultivation tank designed by Ko, in which staghorn and other corals of the genus Acropora are growing together. The corals in the tank resemble a beautiful work of installation art. Demonstrating the functions of its various valves, Ko explains, “Corals like to grow in clean water. There is a water intake at the bottom and an outlet at the top, and there is also a waste discharge valve at the bottom.” We had thought an aquarium bubbler installed at the top of the tank was for aeration, but Ko explains, “Actually, the bubbles create a barrier so that sunlight doesn’t directly hit the corals. Otherwise, the overly strong sunlight would kill some of them.”

It is difficult getting corals to attach to the seafloor here. “When restoring coral reefs in Southeast Asia, they typically lay a framework of steel bars on the seabed and then tie corals to them,” Ko explains. “But we have typhoons here, so we can’t do it that way.” The station staff used to throw cinder blocks on the seabed to build reefs, but they were difficult to fix in place and were often damaged by sea currents or typhoons. Then they started to cast concrete to form hollow blocks in the shape of triangular prisms and pyramids, featuring recesses on their surfaces into which they could plant corals. These were arranged on the seabed to serve as homes for corals. “Think of it as the foundation of a house,” explains You Huiqing, a technician at the station. “After transplantation, the corals grow day by day. The complex three-­dimensional spaces created by the concrete blocks provide shelter for a multitude of marine creatures. The structures become something like high-rise buildings, filling steadily with more and more residents.”

When divers take the plunge to plant corals, they also plant hope.

Public–private partnership

The propagation station operates as a public–private partnership. It provides technology and a platform for legally obtaining coral, and it encourages the private sector to propose coral conservation projects that will bring in more collaborators.

You shares that the station also works with diving outfits to promote environmentally friendly diving. Diving courses include coral planting sessions to strengthen a sense of connection with the sea. On their own initiative, the firms also regularly check on the health of the corals, monitoring their condition and reporting their findings.

“We previously restored an area of around 2,500 square meters, or six basketball courts,” says Ko. “The number of tourist visits annually is hitting 50–60,000 or more.” Now anyone who comes to dive at Suogang in Penghu’s Magong City can survey a vibrant garden of corals in the company of green sea turtles. Footage of coral spawning in the sea off Suogang stirred great excitement last May.

And it’s not only about tourism. “The most important goal in coral reef restoration is creating habitat that will revive marine ecologies and fisheries,” emphasizes Chen.

Taking care to protect their marine ecosystem, local diving instructors regularly check on the health of Hangwan Bay’s corals. (courtesy of Penghu County Marine Life Propagation Station)

In Hangwan Bay near Penghu’s Suogang Fishing Harbor, expanses of purple Acropora corals resemble fields of lavender. (courtesy of Penghu County Marine Life Propagation Station)

Nothing simple about it

Another chapter of this story begins on land. “It is very difficult to grow trees in Penghu,” says Andy Lee, director-general of the Penghu County Forestry and Park Management Center. The county only averages 1,000 millimeters of rainfall per year, but annual evapotranspiration here can reach 1,600 mm. What’s more, the topsoil layer is very shallow at only about 20–30 centimeters, and the islands feature an igneous geology with a pitted surface that doesn’t hold water well. During the northeasterly monsoon season, winds bordering on ­typhoon strength are a feature of daily life.

Three years ago, when the Tse-Xin Organic Agriculture Foundation, which has planted trees in many places throughout Taiwan, came to do so in Penghu, they brought “magic weapons”: water-storing seedling pots. These oval pots are made mostly of recycled paper and can hold 15 liters of water, or roughly a month’s worth of water for a seedling. Wicks in the pots carry water down to the sapling roots, efficiently giving them a steady supply. Covers reduce evaporation of water and reduce temperatures by shading the soil from the sun, while holes in the covers enable the pots to collect rainwater. The pots biodegrade in about a year without any damage to the environment.

These pots have improved the efficiency of afforestation efforts in Penghu. The three-year survival rate of seedlings planted in Penghu with these pots stands at 95%. Lee points proudly to a casuarina tree that has grown from 60 to 250 cm tall.

Cheng Li-yi describes how Tse-Xin planted trees to help protect the Formosan landlocked salmon, another domestic example of using forests to protect fish.

With Penghu’s harsh natural conditions, growing trees here is not easy. But after three years, the planting efforts of the Penghu County Government and the Tse-Xin Foundation are showing some success.

Ocean–forest love affair

While working with the Penghu County Government to plant trees, Tse-Xin shared with them the concept of fish breeding forests. “The concept comes from Japan,” explains Tse-Xin CEO Morris Su. It aims to protect forests so as to protect fish. When trees are planted along the upper stretches of rivers, rainwater carries organic matter such as fallen leaves into the rivers and then to the sea. This provides food for fish, crustaceans and shellfish in the lower stretches of the river and at the rivermouth, which in turn attract larger schools of marine fish to feed on them. It thus bolsters fisheries.”

Cheng Li-yi, director of Tse-Xin’s Tree Planting Initiative, says that fishermen on Oshima Island of Kesennuma City in Miyagi, Japan, have long recognized the industry’s dependence on forests. They discovered that forest nutrients would enter the seas from snow melt at the end of winter, making oysters and other shellfish more abundant.

There are also examples from within Taiwan. Cheng explains that the Formosan landlocked salmon (Oncorhynchus masou formosanus) cannot survive in waters with summer temperatures above 17°C. Unfortunately, mountain districts have been overdeveloped, leading to habitat degradation. In 2021, the Wuling Farm of the Veterans Affairs Council, the Taichung branch of the Forestry and Nature Conservation Agency, and Tse-Xin collaborated in planting more than 20,000 trees in the upper Dajia River watershed. “The larger the area of forest, the more the water will cool as it passes through. And trees, of course, provide shade, which also helps to lower river water temperatures. Moreover, tree litter and the insects that live in the forest provide food for river fauna.” This is a good practical example of the concept of a fish breeding forest.

Morris Su, CEO of the Tse-Xin Organic Agriculture Foundation, embraces the idea of a fish breeding forest, a Japanese concept of protecting fisheries with forests.

From mountains to sea

In mid-April of 2024, the Penghu County Government, Tse-Xin and some private corporations joined hands to promote a visionary satoyama plan for coastal afforestation and coral restoration in Penghu’s Hangwan. They aim to improve 2.5 hectares of forest within three years.

Coastal forests serve as windbreaks and reduce the impact of natural disasters, and they can also protect fisheries. Thirteen tree species suited to local conditions were chosen, including beach naupaka (Scaevola taccada), coastal she-oak (Casuarina equisetifolia), sea hibiscus (Hibiscus tiliaceus), and velvetleaf soldierbush (Heliotropium arboreum), which are planted in areas closest to the shore. To increase biodiversity, additional species such as fragrant pittosporum (Pittosporum pentandrum), Norfolk Island pine (Araucaria heterophylla), pongame oil tree (Pongamia pinnata), and yedda hawthorne (Rhaphiolepis umbellata) are added to the mix in other areas.

On the day of our visit, many citizens came out to plant trees themselves. “When you plant trees,” notes Lee, “you may not see much of a difference in three years, or even a decade. The efforts we expended won’t necessarily be highly visible for a generation. But it is still necessary and important work.” In the fight against climate change, no one is a neutral party. Planting trees is a good place for anyone to start.

These water-storing seedling pots are highly effective in parched Penghu.

In the fight against climate change, no one can claim neutrality. Planting trees is a good place for anyone to start.