This despite the fact that the average altitude of the Yangmingshan hill region is only around 1,000 meters, normally insufficient for snowfall on a subtropical island like Taiwan. But a combination of severely cold polar high-air currents plus the special wind-gap terrain in the area—more precisely, Mt. Chihsing and Mt. Tatun—sometimes makes up for all that. Occasionally, then, denizens of northern Taiwan are offered a prime opportunity to enjoy snowwhite scenery right at home.
In sharp contrast to the peaceful, sometimes snowy, sub-urban recreation scene of today is the history of the region as a theater of volcanic eruptions. In this scenic area, geographically dubbed the Tatun volcanic group, about 2,500,000-500,000 years ago, turbulent flows of lava spread as much as 20 kilometers from east to west, 22 kilometers from south to north, covering the triangular district marked off today by Wanli, Kingshan, and Tamsui.
According to Professor Wang Shin of National Taiwan University, the massive eruptions probably occurred following collision of the Philippine Oceanic Plate and the Eurasia Plate during the early Pleistocene period. The lava and scraps that accumulated cooled off to form Mt. Tatun, Mt. Mientien, Mt. Chutzu, and Mt. Kuanyin in a first stage; Mt. Huangtsui and Tachienhoushan in a second, and finally Mt. Chihsing and Mt. Shamao.
Volcanic terrain in smaller magnitude can also be found in Keelung, Hualien, and on many offshore islands, including Green and Orchid Islands and the Penghus.
The center of the major movements (especially the convergence) involved in the plate tectonics of the Pacific Ocean and the Eurasian mass was later transferred to the Marianas Trench. So like others of the world's 500-plus active volcanic structures, the Tatuns became dormant. But for hundreds of thousands of years now, their ancient activity has given northern Taiwan its special geological aspect. Volcanic traces, including hot springs, solfatara vents, steam fumaroles, hot mud pots, etc., especially on the east side of Kingshan Cliff, extend from the Hokou Delta southwestward along the Huangchi River to the Peitou area and the Taipei Valley.
Affluent creeks and rivers flow over and around the volcanic terrain features, crossing the edges of precipitous gorges to form numerous magnificent waterfalls. The terrain itself is formed largely of an extrusive rock known as Andesite (after the Andes Mountains in South America). The Silk Cataract at Cold Water Hole on the southeastern slope of Mt. Chihsing and the Maple Tree Cataract upstream on the Huangchi River are among the most noted waterfalls.
Some 20-plus conic volcanoes form, northeastward, a concave screen that impedes the spread of the northeastern monsoon, dominator of the area's climate from middle October to mid-May. Clouds, fog, and rain linger there, veiling the lush green mountains in soft white mists.
Adapted nicely to the cold, wet ambience, numerous species of plants and animals generally hailing from higher-altitude regions can be seen in the Tatuns, a special ecological phenomenon.
Their wealth of geological, topographical, and ecological beauty and their favorable situation in the suburbs of metropolitan Taipei have assured the Tatuns their place, also, as a prime recreation area and tourist destination.
MT. Chihsing peaks 1,120 meters above sea level, the highest point not only of the Tatuns, but also of metropolitan Taipei's greater environs. At the center of the Tatuns, it claims a rightful position as troupe leader.
A famous caldera on the northwest side of Mt. Chihsing, Lieuhuangku (Sulfur Valley), covers an area 200 meters long and 150 meters wide. Seen from the Yangmingshan-Kingshan Highway, the elliptical depression resembles a giant's footprint, deep into the slope of the mountain. Sulfur fumes rise here to fill the air with a notably offensive odor, which gets denser and denser as you climb nearer and nearer the fuming cleft. Subterranean sulfur, melted by geothermal steam, vents forcefully with a melodiously hissing or sizzling sound, in accordance with the momentary pressures.
Various minerals give yellow, golden, black, pink, and burgundy tinges to rocks and sands, creating a colorful, picturesque ground. Around the sulfuric steam vent, appended groups of yellow, spruce-shaped crystals are look alikes for conifer needles covered with frost. The crystals, so frail that even the slightest touch of a finger will pulverize them, shiver in the breeze.
Looking downward from the top to the valley, you can see, on the other side of the highway, the old Chutzu Lake bed. Originally formed by the lava "dam" of Mt. Chihsing and Mt. Tatun, it was named Chutzu for its exuberance of bamboos. Then during the Japanese occupation of Taiwan, it was dubbed the "Original Species Rice Farm;" the wet, cold climate here fitted in nicely with the cultivation of the original species of peng-lai rice. Today, the old bed is a green valley of terraced paddies, the major supplier of Taipei's rice and high-altitude (temperate zone) vegetables.
One-hour's climb from Sulfur Valley buys a vantage at the "top of Taipei"—Mt. Chihsing (Seven Stars), known for the seven prominences at its summit. When the chill polar air currents strike in the winter, Mt. Chihsing offers its guests the unforgettable experience of travelling to a snow-bound polar summit within a downhill hike of a hot, steamy valley.
In June and July, the mountain slopes are blooming, covered with a blanket of small, burgundy flowers of rhododendron nakaharai, Yangmingshan's latest-blooming azalea, and unique to Mt. Chihsing.
On one of the area's rare sunny days, screen-like Mt. Tatun, guarded by steep West Peak and rounded South Peak in the west; Hsiao Kuanyinshan (Small Mountain of the Goddess of Mercy), with the Tatuns' largest and most picturesque crater (1,200 meters across and 300 meters deep), in the northwest; and the soaring peak of Mt. Chutzu, the second highest of the group at 1,103 meters, in the north—all are in view. Farther off, the island's northern coast line can be seen. And the exertions and strains of mountain climbing are suddenly overwhelmed by a complicated amalgam of delight and admiration.
On the east side of Mt. Chihsing sleeps serene Lake Dream, a fantasyland pool shrouded in mists year around. Another name, less romantic, is Pool of Teals, for the autumn swarms of migratory ducks from northern lands that find a traveler's shelter here. The seeds of water leek, probably brought by the teal from cool-weather zones, have gradually developed here into a new species, unique to Taiwan. Botanists called it isoetes taiwanensis; its sole range, Lake Dream, is the southernmost point for the occurrence of water leek.
On the southeast of Mt. Chihsing, Chingtienkang's (Sun Valley's) prairie stretches four kilometers northeastward to Mt. Huangtsui and Tachienhoushan. Grazing cattle here impede the growth of plantlife, and the prairie is an endless green carpet, an attractive invitation to somersaults. In autumn, small yellow and white flowers dot this green blanket, an extravaganza for the romantic eye.
Striding here over the turf startles numerous grasshoppers and other small jumping insects. These little denizens offer delicious meals for larger wildlife. A guinea fowl ambling serenely in the vicinity of its home is one example. Four big-crown eagles soaring above are not.
Spiders' webs embellished with little, round dewdrops are everywhere, embroidered across the grass coverlet.
Butterflies of the papilionidae family in summer, and of the smaller-sized pieridae family in winter, can be seen flashing their wings everywhere over the prairie.
Here is sulfur, ready for a thousand uses.
Bathing in the warm sunshine, giant Chihsing seems to have fallen soundly asleep, and the vast stretch of Sun Valley sweeps across below. Far away, the bright green meadows of Bamboo Pole Ridge shape a graceful curve against the sky.
The valley fragrance of sweet, tender, grassy shoots blows in the soft breeze. The placidly pastoral ambience successfully masks the volcanic origins of the valley, until you stroll over to a cliff edge.
Off the rocky edge, left by a cataclysm of a younger earth, miscanthus grasses stipple a scene of utter desolation. Ahead, flat-topped Mt. Huangtsui and its satellite volcano, Tachienhoushan, hold a trace of old lake in between. Between Mt. Huangtsui and Sun Valley, the Tayoukeng (Big Sulfur Vent) caldera roars with messages from the heart of the earth. Furious white steam vents at a heat of 120°C, marking the most vehement fumarole in the whole region.
Huddling in the valley between Mt. Chihsing and Mt. Chiku, Matsao Hot Spring (the Manger) puffs hot steam through layers of rock and gravel. Like most other springs in this prolific strip—18 kilometers long and 3 kilometers wide—Matsao Hot Spring is sulfurtainted, undrinkable. But in all four seasons, people come here from around the island to bathe in the hot springs, whose rich mineral brew is said to be a curative for skin diseases, and helpful for victims of rheumatism and arthritis.
Approaching through a vast expanse of virgin, broad-leaf forest, in which Taiwan's blue magpies glide sprightly along over-and-under air routes, hikers reach the joining point of the Matsaochi and Luchiaokengchi Rivers. The waters of the former, red with silt, contrast sharply with the crystal clear currents of the latter. Such scenes are abundant in the Tatuns, and never cease to mesmerize observers.
CLOTHED in the colorful blooms of various azalea species, among which rhododendron longiperulatum is the most unique, Mt. Tatun in spring is justifiably regarded as one of the region's eight top scenic highlights.
The most popular hikers' route enters by Pakala Highway via Mt. Tatun, Mt. Mientien, and Mt. Hsiantien and exits in Peitou. It is customarily referred to as the "Gallery of Butterflies." Year around, but especially in spring and summer, swarms of butterflies fly the route at the invitation of fetchingly aromatic flowers. Their number reaches its maximum during the late meiyuchi, the rainy season in May and June when plums are ripening.
As the sun begins to shine through the clouds in the early morning, tens of thousands of the young imagoes of parantica melaneus swinhoei and the parantica sita niphonica take flight from the waist of Mt. Tatun towards Mt. Mientien; the sky is almost shielded by them. According to naturalist Chen Wei-shou, about 133 species of butterfly occur in Yangmingshan and, on the right occasions, at least 50 species can be observed in the Gallery of Butterflies every day.
Even without butterflies, Mt. Tatun is still an excellent hikers' destination. The fresh air at the peak of the kingly mountain, 1,081 meters above sea level, is worth profound and undisturbed gourmet sampling. Inferentially, the last eruption of Mt. Tatun must surely have been very peaceful, with a glutinous lava flowing slowly to cover the mountain top in a graceful leisure cloak.
Viewed from Tatun's peak, the troupes of volcanoes and rivers radiate in all directions. To one side, the rounded peaks of Mt. Mientien and Mt. Hsiantien compose a saddleback. On the top of Mt. Mientien, a funnel-shaped crater 230 meters across and 45 meters deep becomes a pool on rainy days. It is known as Heaven-Facing Pool. On clear days, the dry crater bed, clad in greenery, is a good location for a picnic. When large parties frolic there, it perhaps does not occur to them that the ground under their feet was once piping hot lava.
Persistent mountain fogs inhibit long stays on Mt. Tatun. Driving down the Yangmingshan-Peitou Highway, motorists can often see blue skies extending on and on ahead, while behind, Mt. Tatun has already sunk beneath gray mists.
On two sides of Yangmingshan's second park, towering Mt. Chihsing and its delicate satellite volcano, Mt. Shamao (it derives the name for its resemblance to official headgear of old China), stand face to face. The comparatively thin, cross-layered composition of lava and scraps that make up Mt. Chihsing's slope smoothly form its conical shape. The dense, simple lava structure of Mt. Shamao is bell-like.
The diverse forms and ridgelines of the two volcanoes leave totally different impressions on a viewer's mind-another approach to beauty.
In the foothills of Mt. Shamao, a wealth of geothermal energy is sited at Erhchungchi (Dale of Two Creeks).
Tahuangtsui (Big Sulfur Mouth) on the west of Erhchungchi has a 300-year history of sulfur mining according to Taipei County records. During the reign of Emperor Kang Hsi of the Ching Dynasty, one Yu Yung-ho from Chekiang Province came to the island to mine sulfur for the production of gunpowder. During the later reign of Emperor Chien Lung, private development of sulfur mines was forbidden, and a specific factory was designated to extract sulfur here by means of the solvent method. The mining premises referred to in the records are believed to be at today's Tahuangtsui and Kingyuanfen (Wealth of Minerals) near Peitou.
Today, Tahuangtsui is no mine, but the hot spring source for Peitou Spa. Any traces of mine development from the Ching Dynasty have long since been buried in the sands. Only steam and the sparkle of hot water can be seen here now. There is no memorial of the past.
Overlooking the Tamsui River, outside the scope of Yangmingshan district but within the region of the Tatuns, Mt. Kuanyin, shaped and named for a reclining Goddess of Mercy, looks down on numerous small sailboats taking the wind.
A 600-meter hill composed of volcanic agglomerate, Mt. Kuanyin looks far bigger when viewed across the foil of the Tamsui River to the east and against the Linkou Plateau to the west.
Long ago, when Mt. Tatun and Mt. Kuanyin were erupting, flowing streams of lava blocked the river and created the then Taipei Lake. Over the ages, a gorge was finally worn through the lava, and the lake water began to drain down the Tamsui River and its branches; the bottom of the lake was gradually revealed. We can almost count back to that time on our fingers—it has been no more than 200 years since the emergence of the Taipei Basin. Contemplating the flourishing, high-rise present of Taipei and recalling its past geology, we cannot but wonder at the impermanence of the world around us.
New Peitou's Valley of Subterranean Heat is another wonderland of volcanic origin neighboring the Yangmingshan district. Traces of post-volcanism include fumaroles and hot springs. The hot water, acidified with sulfur dioxide, eroded a basin for marshland in the solid rockbed. Vapor fills the whole valley year round. Bubbling and boiling water venting from a rugged pool gives a mysterious and horrible extra twist to the ambience. Such pop-names as "Lake of Ghosts" and "Hell Valley" are in wide currency.
The oval valley, 40 meters wide and 100 long, is full of piping hot springs. Put an egg in a spring and it takes but a few minutes to cook it thoroughly.
Travel among the Tatun volcanic group recalls primeval ages in which traces of human intrusions were distant in both time and space. To keep the ambience of this land of original beauty at its most pristine, the Construction and Planning Administration of the Ministry of Interior has now mapped a preservation plan as an augmentation of the area's recent designation as Yangmingshan National Park, according to Tsai Hui-min, a national park planner. Hopefully, a trip through the Tatuns will be even more enchanting following the completion of the project.