Welcome to the first installment of our series, “Plants Climbing Mount Fuji.” Today, we’ll focus on the vegetation found at the mountain’s base, which we’ll refer to as the “1st Station” in our multi-part exploration.
Japan’s Diverse Vegetation
The Japanese archipelago stretches from Hokkaido in the north to Okinawa in the south—roughly between 20° and 46° north latitude, spanning about 3,500 km. In general, the types of plants that grow in different regions are determined by average temperatures, which vary with latitude. This is known as horizontal distribution.
Vertical Distribution: The Impact of Elevation
Temperature also changes with altitude. As elevation increases, the temperature drops by about 0.6°C for every 100 meters of height gained. For Mount Fuji, this means a difference of about 23°C between sea level and the summit at 3,776 meters. This temperature variation causes the types of plants growing on Fuji to change with elevation—a phenomenon called vertical distribution.
Comparing Horizontal and Vertical Distribution
Looking at Japan’s vegetation horizontally, the northeastern regions are dominated by deciduous broadleaf forests (mainly beech, in what’s called the “summer-green forest zone”), while the southwestern regions are home to evergreen broadleaf forests (mainly oak, in the “laurel forest zone”). Mount Fuji sits near the boundary between these two zones.
The temperature changes experienced as you ascend Mount Fuji—dropping 0.6°C every 100 meters—are, in effect, a condensed version of the horizontal temperature changes found across Japan. In fact, the vertical temperature gradient on Fuji is about 1,000 times more pronounced than the horizontal gradient across the country.
Additional Influences on Plant Life
Temperature isn’t the only factor affecting plant growth. Other conditions—such as atmospheric pressure, ultraviolet radiation, sunlight, wind, rainfall, snowfall, and soil quality—also play important roles. For example, even at the same elevation, the vegetation on Fuji’s northern and southern slopes can differ.
How Does Plant Life Change with Elevation on Mount Fuji?
Up to about 1,000 meters in elevation, human activity has a strong impact, and much of the original vegetation has been altered. However, based on available clues, it’s estimated that the boundary between evergreen and deciduous broadleaf forests is around 800 meters. On Mount Fuji, this corresponds to areas such as Lake Kawaguchi on the north, Asagiri Plateau on the west, Fuji Safari Park on the south, and Subashiri Sengen Shrine on the east.
The upper limit for deciduous broadleaf forests is about 1,600 meters. Above this, you’ll find subalpine coniferous forests dominated by fir and spruce. Near the treeline, larch becomes more common and can be found up to about 2,400 meters. Beyond this is the alpine zone.
Plants That Defy Elevation
Some plants, known as “human-disturbed plants” or “weeds,” are found from the foothills all the way up to the upper subalpine zone. A good example is Plantago asiatica (commonly called “Ōbako” or plantain).
Spotlight: Plantago asiatica (Ōbako)
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Distribution: Hills to upper subalpine zones
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Habitat: Roadsides, vacant lots
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Life Form: Perennial
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Height: 10–50 cm
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Flowering Season: Early summer
The name “Ōbako” means “large leaf,” but it’s also called “Shazensō,” meaning “plant by the roadside,” because it typically grows along paths and roads. The seeds, known as “Shazenshi,” have been used in traditional medicine as a cough remedy.
Interestingly, plantain is often found along hiking trails, where it spreads by clinging to the soles of hikers’ shoes—literally “climbing” Mount Fuji with people!
Next time, we’ll continue our journey up Mount Fuji to the 2nd Station. Stay tuned!
