Oshima Cherry Tree

The Sakura-kabu of Oshima: An 800-Year-Old Cherry Tree That Refuses to Die

On the volcanic island of Izu Oshima, about 120 kilometers south of central Tokyo, stands a cherry tree unlike any other in Japan. The "Sakura-kabu" of Oshima — literally "the Cherry Stock" — is an ancient Oshima cherry (Oshima-zakura) whose main trunk snapped centuries ago, leaving only its massive base. From this broken stump, the tree refused to die. Instead, its fallen branches rooted themselves in the volcanic soil and rose up again as new trunks, surrounding the parent like a quiet family of descendants gathered around an elder.

Estimated at over 800 years old, this is the oldest and largest Oshima cherry in existence — and the only Special Natural Monument designated for a plant in all of Tokyo. To stand before it in early spring, when fragrant white blossoms float over a tangle of writhing limbs and exposed roots, is to witness something most cherry-blossom viewers will never see: not a tree in its prime, but a tree that has learned how to live forever.

A Tree Born of Volcanic Fire

Izu Oshima is the visible peak of an active volcano, Mt. Mihara, that has shaped the island's landscape through countless eruptions. The Sakura-kabu grows at an elevation of about 230 meters along the path from Tokyo Metropolitan Oshima Park up toward the summit of Mt. Mihara. It is rooted, remarkably, on top of a lava field — a stretch of black basalt that once flowed across this slope.

Geological surveys long suggested the tree must have grown after the great eruption of 1552, when fresh lava buried the surrounding ground. But more careful study of the local topography has revealed something extraordinary. The patch of earth on which the cherry stands sits slightly higher than its surroundings, and Izu Oshima's low-viscosity basaltic lava flowed around it rather than over it, splitting into two streams just before reaching the tree. The cherry survived as if on a small island in a sea of fire.

Geologists borrow a Hawaiian word — "kipuka" — to describe such an isolated patch of old forest left untouched by a younger lava flow. The Sakura-kabu is one of Japan's most famous kipuka residents, a single tree that has outlived eruption after eruption while everything around it was reborn as stone.

How a Cherry Tree Learns to Walk

The tree's appearance puzzles many first-time visitors. There is no soaring, symmetrical canopy. Instead, the main stock (moto-kabu) is a low, weathered base about two meters tall, its upper trunk long since dead. Heavy limbs lie across the ground like sleeping dragons, and at three nearby points — to the north, east, and west — new trunks rise upward from the soil.

These are not separate trees. They are all one organism. Over the centuries, severe winds and typhoons broke off large branches, but rather than dying, each fallen limb sent out adventitious roots from its underside where it touched the soil. New shoots then climbed upward from those roots, becoming trunks in their own right. Tree specialists call this phenomenon "the cherry that walks": a tree that gradually relocates itself by collapsing in one direction and rising again from where it falls.

A particularly large branch toppled in a strong wind in May 2004, and another major collapse followed during a typhoon in 2005. Yet the Sakura-kabu still blooms every spring. Today it survives as the original stock plus three child trunks — north, east, and west — all connected underground by a remarkable circulatory system in which adventitious roots draw water and nutrients from soil far from the original base and feed them back to the ancient core.

Why It Was Designated a Special Natural Monument

The Sakura-kabu was first designated a Natural Monument on December 24, 1935, and elevated to Special Natural Monument status on March 29, 1952. Special Natural Monument is Japan's highest tier of natural heritage protection, reserved for objects of "particularly high scientific or cultural value." Across the whole of Tokyo, this single cherry is the only plant to hold the designation.

Several qualities earned it this distinction. It is the oldest and largest known Oshima cherry, with a base circumference of roughly 7.9 meters. It is the most spectacular wild example of the species that gave its name to a whole lineage of Japanese cherries — Oshima-zakura is the male parent of the Somei Yoshino, the cultivar that paints Japan pink each April. And the tree's astonishing capacity for self-regeneration, observed over generations, is considered scientifically rare even among species known for producing adventitious roots.

Equally important is its cultural longevity. Local people have protected the tree since long before it received any official recognition. They call it "Sakurakkabu" in their dialect, and traditions remember when its trunk was wrapped in shimenawa rope and offered gohei paper streamers in the manner of a sacred tree. The early scattering of its blossoms was once read as an omen of storms or poor harvests.

The Lighthouse of Sailors and the Cherry of Legend

In the Edo period, before lighthouses and modern navigation, sailors crossing the strait from the Boso Peninsula on Japan's mainland used the Sakura-kabu as a landmark to guide them toward the port of Izumitsu on Oshima's northeastern coast. From the sea, the enormous white-flowering crown would have stood out brilliantly against the dark green island and the black lava slopes around it — a living beacon of spring.

The tree is also wrapped in older legend. One tradition holds that En no Gyōja, the legendary ascetic and founder of Shugendō, planted it with his own hand. En no Gyōja was exiled to Izu in the year 699, and if this story were true, the Sakura-kabu would be over 1,300 years old. Most scholars consider 800 years a more reliable estimate, but the legend captures the awe the tree has long inspired in those who encounter it.

Highlights and Best Time to Visit

The Sakura-kabu is reached by following the Ajisai Rainbow Line, a scenic road that branches off the island's coastal loop just past Tokyo Metropolitan Oshima Park. Wooden walkways and explanatory panels surround the tree, allowing close, respectful viewing from multiple angles. The site is on a wooded slope, with a southern face shaded by tall hortinia (horutonoki) and Japanese chinquapin (sudajii) trees that the cherry has spent centuries growing around.

Late March is the prime moment. Oshima cherry opens its blossoms and its fresh green leaves almost simultaneously, so visitors see white petals layered against young foliage rather than the bare-branched pink familiar from Somei Yoshino. The total floral display is modest in volume — this is an aged tree, not a young one — but unforgettable in atmosphere. The Japanese aesthetic of wabi-sabi, the beauty of impermanence and age, has rarely a more eloquent expression.

Camellia (tsubaki), Oshima's signature flower, is often still in bloom at the same time, layering crimson and white across the island's landscape. The journey from the Sakura-kabu upward along the road brings visitors into the broader caldera of Mt. Mihara, with its black volcanic desert and sweeping views.

Around the Sakura-kabu

Tokyo Metropolitan Oshima Park, just down the road, is one of the largest free-admission zoological parks in Japan and famously the home of Asian black bears, primates, and birds in spacious enclosures. Mt. Mihara itself is a roughly two-hour round-trip hike from the parking area at its base, crossing a lunar-like expanse of black scoria and visiting the steaming summit crater. The island's southwestern coast holds Sunoharimon, a striking cliff of layered volcanic strata that records thousands of years of eruptions in cross-section.

For travelers from central Tokyo, Izu Oshima is reachable by overnight ferry from Takeshiba Pier in roughly six to eight hours, by jet ferry in about 1 hour 45 minutes, or by short flight from Chofu Airport. The island feels worlds away from the metropolis to which it formally belongs.