“Controllers” of the Forest

The beech family, Fagaceae, is a family of flowering plants that includes beeches, chestnuts, and oaks. Their most familiar feature is the fruits, known as calybia, which are fully or partially enclosed in a protective structure called the cupule.

Fagaceae are widely distributed in the northern hemisphere. At first glance they appear similar to other woody plants, but for Lin Huan-ching, author of Oak Family in Taiwan, they are very special.

Lin Huan-ching has personally climbed every giant tree of the Fagaceae family in Taiwan to photograph these plants from various angles. (courtesy of Lin Huan-ching)

Fascinating Fagaceae

At age 26, Lin took a job at the Lienhuachih Research Center of the Taiwan Forestry Research Institute (TFRI). In the center’s offices, surrounded by woodland, he looked at a fruit calendar on the wall and thought: “Why don’t we hang a calendar of forest fruits?”

Filled with enthusiasm, each day he used his free time to go into the forest and take photographs. His colleagues joked that he had been “enchanted by tree spirits.”

This enchantment caused him to progress from publishing a calendar to compiling an illustrated field guide, and he even resigned from his job to devote himself fully to exploring all 46 species of Fagaceae in Taiwan.

He used his camera to record Fagaceae family plants all over Taiwan, showing their wide variety of shoots, green leaves, flowers, reproductive organs, branches, and fruits. He accompanied the photos with easy-to-­understand text, discussing their origins and habitats, and even including many amazing stories of his relationships with them.

Some Fagaceae have flowering periods that are measured in years. One of these is the Nantou tanoak (Lithocarpus nantoensis), a Taiwanese endemic species. With the period from budding to flowering being very short, Lin was worried that he would miss the day of efflorescence. But to his surprise, one night in a dream he saw a waving leafy branch reminding him that it would soon be time to photograph the bloom, and just a few days later he really did see signs of the flowers preparing to blossom.

It took Lin more than four years to write Oak Family in Taiwan, the first field guide to Fagaceae in Taiwan. It was finally published in 2019. Not only was it praised by local botanists as an homage to Faith in a Seed by the pioneering nature writer Henry David Thoreau, it also crossed over to general readers.

Lin’s book Oak Family in Taiwan. (courtesy of My House Publishing Company)

According to the late plant taxonomist Liao Jih-ching, Fagaceae plants in Taiwan belong to five genera: Castanea (chestnuts), Fagus (beeches), Castanopsis (evergreen beeches), Lithocarpus (stone oaks), and Quercus (oaks). (courtesy of Lin Huan-ching)

The woodland buffet

However, Lin says with a smile that in reality Fagaceae are not always as beautiful as in the book. “In fact you could say they are a mess.” He says that the ground around them is often covered in empty shells left by squirrels and other rodents after they eat the seeds, the buds are scarred with the teeth marks of mammals like the Formosan Reeve’s muntjac, and there are countless small holes in the leaves gnawed by insects. At flowering season the pollen also attracts creatures like butterflies and moths.

Thus each Fagaceae plant is actually a “woodland buffet.” Lin notes that they are important platforms for resource and energy exchange in the forest. They are also useful to humans in many ways.

In 2021, the TFRI discovered a new species of whitish truffle, Tuber lithocarpii, living parasitically on the roots of a Konishi tanoak (Lithocarpus konishii). In 2024, scientists discovered wild yeasts growing in a Fagaceae forest, and gene sequencing showed these yeasts to have the greatest genetic diversity in the world.

Lin says that although Fagaceae are not the most prolific plant family in Taiwan in terms of the number of individual plants, they have the greatest biomass. “Hence the role that Fagaceae play in Taiwan’s forests is comparable to that of the Taiwan Semiconductor Manufacturing Company in the economy.”

Hsu Chun-kai, chief of the Lienhuachih Research Center (LRC), tells us about the “Lauro–Fagaceae association,” an important grouping of flora in Taiwan’s low- to medium-elevation woodlands. Fagaceae and Lauraceae (the laurel family) constitute an important combination in Taiwan’s forests, and have a competitive advantage in the canopy space. They can be said to be “controllers” of the forest environment.

The Lienhuachih Research Center of the Taiwan Forestry Research Institute is located in a valley in Nantou County’s Yuchi Township. Because it preserves many endemic plant species, it is known as a “Noah’s Ark for low-elevation plants.”

Squirrels play an important role in the reproduction of Fagaceae plants.(MOFA file photo)

A Noah’s Ark of Fagaceae trees

However, when we consider the reproductive rate of Fagaceae, the term “controllers” seems somewhat out of place.

Firstly, in contrast to “pioneer” species whose seeds are spread by the wind, Fagaceae depend largely on the food storage behavior of squirrels to relocate seeds and enable them to reproduce, a process that is slower and more limited spatially.

Secondly, if Fagaceae are toppled by strong winds or other causes, the trees will regenerate through buds or shoots. But while this enables the fallen tree to survive, it does not add to the population of the species. These two characteristics represent natural mechanisms that ensure that there are not excessive numbers of Fagaceae plants. However, faced as they are with climate change, shrinking habitats, and excessive logging, this adds to the challenges of their existence.

The LRC, dubbed a “Noah’s Ark for low-elevation plants,” has been preserving biodiversity since the era of Japanese rule. The Nantou tanoak that Lin Huan-ching saw in his dream is one of 11 native Fagaceae species on the land managed by the center, and is one of the species in need of conservation.

Hsu Chun-kai points out that the Nantou tanoak has a limited range of distribution and a small population, so it is listed as a vulnerable species. The LRC is working with the Forestry and Nature Conservation Agency to implement seed collection and germplasm conservation measures in order to undertake artificial propagation of Nantou tanoaks, to overcome obstacles to reproduction such as its fruit being eaten by wildlife, and the large number of empty shells. The LRC is planting about 0.8 hectares of land with Nantou tan­oaks in the hopes that they can work on two fronts at once: in-situ preservation in the tree’s original habitat as well as ex-situ conservation at the LRC.

Research shows that Fagaceae plants show greater diversity in subtropical regions than in tropical or temperate regions. Subtropical Taiwan has 46 species of Fagaceae, of which 11 are endemic, a high level of diversity considering the island’s small area.

In addition, Taiwan’s Fagaceae are characterized by “reproductive isolation.” For example, in Anshuo Forest in southeastern Taiwan the endemic narrow-leaved oak (Quercus longinux) produces acorns more than twice the size of those it produces elsewhere.

Differentiation among Fagaceae species is the result of tens of millions of years of evolution. Lin Huan-ching laments that because past studies were not extensive, Fagaceae plants were seen simply as part of mixed woodland. “But over the past several years it has been confirmed that they provide useful evidence for studies of plant movements and geographic distribution during the Ice Ages, and they are repositories of precious ‘natural histories’ that even modern technology cannot yet decipher.”

Endemic Taiwanese Fagaceae growing in the Lienhuachih Research Center nursery all have a red-and-white pole inserted into the ground nearby to remind staff to take good care of them.

Juhu Ecological Park’s “Oak Hill” is located on a ridgeline in the mountains of Taitung County’s Changbin Township, from where one can gaze out over the Pacific Ocean.

Planting the seeds of sustainability

A key player in Taiwan’s Fagaceae conservation efforts has been Lai Jintian, the boss of Juhu Ecological Park in Taitung. Nimbly scrambling up a Nantou tanoak, Lai places a net over the canopy to protect the developing acorns from animals. Lai is writing a new page for Fagaceae conservation in Taiwan.

Asked about his story, Lai modestly responds: “I just think of things from a farmer’s point of view.” After retiring from the military, the youthful Lai moved back to his old hometown of Changbin to farm. He saw the power of nature during a natural disaster, and began to pay attention to the natural environment. He switched over to organic farming and began planting tree species native to his home area.

Through more than 30 years of tree planting, entirely by his own efforts, today he has grown 30 hectares of woodland, including Fagaceae species.

Lin has visited mountain forests across Taiwan to collect Fagaceae fruit, and used seed stratification to overcome seed dormancy and enable the trees to grow. After observing the saplings’ development, he moves the most robust ones to a specially selected ridgeline on his land. He provides them with six to seven meters of space to develop—enough room for at least 20 years of growth.

Like his elderly father, Lin keeps a close eye on “Oak Hill,” periodically touching the trees to check their condition and ensuring that the mesh guards protecting the saplings are in good condition.

Besides planting trees, Lai also works with scholars, recording detailed data on the trees’ growth. Given that Fagaceae research has only gradually become more comprehensive in recent years, while there are quite complete records of fully grown trees in the wild, there is a lack of information about sapling growth. Therefore Lai records data on the growth of his Fagaceae plants including time, humidity, and temperature, compiling a phenological study for Changbin Township. The data is continually uploaded to international websites, making a contribution to global Fagaceae research.

Nonetheless, ex-situ conservation is not easy, facing obstacles such as regional differences in soil properties, climate, and moisture. Looking at a short-tailed-leaf tanoak (Lithocarpus brevicaudata) that has started to produce small fruits at the treetop, and comparing it to a stunted Mori oak (Quercus morii), you can’t help but wonder how two trees planted at roughly the same time can end up so different. Lai says that the reason is perhaps that the Mori oak is mainly found in areas above 2,000 meters in elevation, so that it doesn’t respond well to the low-elevation environment of Changbin. He adds that every plant has its own ideal natural habitat, posing limits to ex-situ conservation.

Collaboration between government and the private sector not only can preserve habitats, but also can preserve fruits, so that like squirrels storing up acorns, people can create a sustainable future for the forests of Taiwan and preserve biodiversity in natural ecosystems. In this way we can ensure the diversity of Fagaceae plants and enable these “controllers” of the forest to continue to play an important role in nature.

Juhu Ecological Park owner Lai Jintian says he has achieved a degree of success in his ex-situ conservation of Fagaceae trees. In the future he will continue to observe forest ecosystems and do his best to contribute to the study of nature.

Insects including ants, butterflies, moths, and bees are attracted by the sweet nectar produced by Fagaceae plants during flowering season.