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Thursday, Sept. 4, 2003
GREEN AMID THE SNOWS
Labrador tea and forests to walk on
By MARK BRAZIL
During the heat of a Honshu summer it is hard to imagine that there are hints of tundra here, or that refreshing tea might come from an unusual source. However, the alpine regions of high-altitude Japan, and small areas of the cool, fog-shaded regions closer to sea level in southeast Hokkaido, not only resemble tundra, but also amazingly share some of the very same plants.
While lowland urbanites swelter for month after month, summer on the tundra may last for just the two months of July and August. Temperatures can fall below freezing even then, and the wind can be very drying. Plants that live in such places live on the edge, with their toughness enabling them to eke out an existence in the poor acidic soils.
In this environment, plants tend to be small, ground-hugging, mysteriously able to survive repeated freezing and thawing, and able to cram their entire lives into the brief warmth of summer.
True tundra (a word derived from the Finnish tunturia, meaning "a barren area") spreads across the northernmost parts of the Eurasian and North American land masses. It is the treeless zone that is draped like a thin, frigid blanket around the North Pole.
This region of the Earth is surprisingly desertlike, with most of the little annual precipitation it receives falling as snow. The melting snow in spring and early summer forms temporary pools and marshes, since only the surface soils thaw and below that the permanently frozen layer prevents drainage. Upstanding trees cannot grow on the tundra because the permafrost, which is not far beneath the surface, prevents them from putting down deep roots. It's not surprising, therefore, that the characteristic vegetation is comprised of shallow-rooted, creeping plants that present little stature to the wind.
Although the tundra is blessed with 24 hours of daylight during the summer, the winter is dark and seems endless. As a result, the growing season may last no more than 60 days, and around the larger snow patches in the mountains of Hokkaido the summer is hardly longer.
Although there may be no tall trees on either the tundra or in the Japanese alpine zone, similar tree species, such as dwarf willows and birches, survive in both regions by adopting an unobtrusive growth form -- they creep along the surface, forming a forest canopy that may be no more than 10-cm high.
Whereas in tropical forests the canopy towers as much as 40 meters above the ground, on the tundra, or up in the alpine zone, it's quite possible to walk across the top of the "forest" canopy without even noticing it.
One Holarctic plant well-adapted to the harsh conditions found on poor soils in cold regions is the ledum. Going by a host of names -- from Duke of Argyll's tea tree to Iso-tsutsuji -- the Ledum palustre of Japan is a member of the Ericaceae, or heath family of plants. It's a shrubby plant, a low evergreen species that attains no more than a meter in height even under ideal conditions. Its narrow, elongated leaves are rather leathery, and are a shiny dark green above and cinnamon brown and hairy underneath, with curled-down edges. Its flowers are delicately attractive, forming foamy white umbel-like clusters on slender stalks from as early as May, and I have found many still flowering at higher altitudes well into July. I have heard that when walking among ledum bushes one can smell a sweet, spicy aroma -- perhaps I walk too gently among them, for I have not noticed the scent myself.
However, despite being widely known as Labrador tea, Iso-tsutsuji is not related to other plants we know by the name of tea.
This plant is at home in Alaska and Greenland and from Canada south to New England and Oregon, as well as in northern Europe, across Siberia and in Japan, too, in Honshu and Hokkaido. It grows in cool, moist, acidic soils.
Sometimes in shady forested areas it is abundant, forming raised carpets of frothy flowers. While being at home in wet areas, it is also surprisingly capable of surviving fires by regenerating quickly from its rhizomes. As such, it is typically one of the first plants to recolonize burned bogs.
In addition, in its continental range it forms the browse of large mammals such as moose and caribou, and its strongly aromatic leaves are rich in vitamin C. Here in Japan, though, I have never seen signs of it being eaten, not even by deer.
This attractive plant has important healing properties and can be used externally and internally. Externally, it can apparently treat various skin conditions; taken internally, it helps stimulate the nerves and the stomach. Syrup made from the plant can also be used to ease coughs and throat complaints, but the plant is better known for the palatable herbal tea with a spicy fragrance that can be made from its leaves (hence the name). The leaves can also be added to black tea to give it flavor, or mixed with willow-leaf tea for a potently medicinal mix.
Tundra plants, including the Labrador tea, are now known to be able to get a jump start on summer by beginning photosynthesis beneath the snow before it has fully melted away. In late spring and early summer, these plants are safe beneath the protective layer of snow but still receive sufficient light to operate at up to 20 percent of summer efficiency. It seems more than likely that alpine plants do the same here in Japan, as snow patches linger in the mountains throughout July. As they melt, however, plants emerge that are already deep green, and they must rush to benefit from the brief summer.
Mark Brazil welcomes readers' comments at firstname.lastname@example.org