tokyo’s hinterland

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Panoramic view of the mixed deciduous forests from the summit of Tennosan Mountain, Okutama

The metropolis of Tokyo is better known for its dense urban center surrounded by the Yamanote line, but so-called Tokyo-to includes 23 wards that stretch to the western edge of the Kanto Plain. Bordering Kangawa and Saitama Prefectures, the mountainous extremity of Tokyo is the source of the Tamagawa River and has several natural and rare habitats of alpine fauna and flora. At around the 1700m altitude in Okutama, near the summit of Tennosan Mountain, the cedar forests that blanket the hills below recede, giving way to a mixed deciduous forest. Autumn arrives in Okutama’s hills earlier than Tokyo, with temperatures plummeting from the mid-20s in the daytime to just above freezing in the evening. With the dramatic temperature swings in October, the deciduous forest is alight with the crimson reds of Sumac in the understory, the auburn palmate leaves of Sycamore, and the delicate ochre of Japanese Maples in the upperstory, and the bright yellow and orange Larches in the upper alpine reaches of the mountains. The cedars at lower elevations retain their evergreen boughs, the coniferous forest itself mute with an army of perfectly vertical trunks and a forest floor where nothing grows under the darkness of the dense shade.

The remaining mixed deciduous forest near the summits of Okutama is what Tokyo probably used to look like before its first growth forests were cut down to build Edo when the capital was relocated by the Shogun Tokugawa. Forests that could be felled easily in the lower slopes were carted off to the east to be turned into shrines, temples, Edo castle itself and to satisfy the housing for the masses that settled in the Kanto Plain. Cedars were planted in the aftermath of the indiscriminate logging, creating a massive monoculture that exists to the present-day. Cedars being revered for their capacity to resist water damage and insect (especially termite) infestation, were the logical choice for re-planting. Deciduous hardwoods, although prized for their strength and beauty, needed much more tending and maintenance as they were susceptible to various types of damage, reducing the yield as compared to the favored evergreens.

The consequences of this monoculture on such a large scale have affected not only the natural ecology of the mountains in western Tokyo, but also the habitat of fauna and on the air quality all the way in the metropolis. Fauna like the Japanese Macacque (Macaca fusata) have retreated to higher elevations where the supply of food is plentiful and the environment conducive to their natural habitat. The mixed deciduous forest includes fruit and nut-bearing varieties like the Japanese Chestnut (Castanea crenata) which litter the forest floor with edible nuts that the monkeys gather. At lower elevations, with only Cedar pinecones and pine needles on the forest floor, the food-barren environment stands in shadowy silence.

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A Japanese Macacque with its baby on a branch in a Chestnut grove

When Spring arrives, Cedars release massive amounts of pollen which is sent eastwards when air borne, mixing with pollution in the city and becoming a noxious mixture that is attributed to the high incidence of hay fever. With few permeable surfaces in the city, the allergy-causing concoction swirls around, reducing the air-quality significantly enough that many urbanites don masks and take prescription medication over weeks of eye-watering suffering.

On the descent from Toridaniyama Mountain, one of the tallest peaks in the area, its possible to see all the way to Tokyo’s skyscrapers. A three hour train ride from Tokyo Station, a 20 minute bus ride to the foot of the mountain and a two day hike to an elevation of nearly 2000 meters and Tokyo is still clearly visible on a crisp fall day. Roppongi Hills, the Tokyo Tower, and the Shinjuku Towers can easily be perceived on the horizon within the vastness of the Kanto Plain.  Despite the great distances, Tokyo’s influence has collapsed space and what would seem to be a modern ecological problem actually started as the first trees were being felled 400 years or more ago. Ecological systems in the globalized world don’t obey man-made borders and certainly today, the demands of a city like Tokyo can mean overfishing in places as far-flung as Canada or clear-cutting in the depts of Amazonian Brazil. Okutama is a microcosm of this phenomenon, demonstrating that the frame of the city as ecosystem needs to be expanded to be comprehended in its entirety.

Toridaniyama

The view to the Kanto Plain and Tokyo’s skyscrapers from Okutama