日本の樹木支柱の種類と歴史──鳥居・八ツ掛・布掛・やぐら、竹と杉丸太としゅろ縄の手仕事|樹木医が解説(Japanese Tree Staking: Torii, Yatsugake and Nunokake)

English: Japanese Tree Staking — Torii, Yatsugake, Nunokake and Yagura, Built by Hand from Bamboo, Cedar Poles and Palm-Fibre Rope

Japanese tree stakes protect newly planted trees from the wind, and they come in several forms: torii, yatsugake, nunokake, gassho, yagura and hedge stakes. Drawing on the standard drawings of the City of Yokohama and Tottori Prefecture and the guidelines of Japan’s national research institute, this article explains the types and how they are chosen, how they are installed, how bamboo, cedar poles and shuro (palm-fibre) rope are tied, and when the stakes should come off.

Anyone who has walked through a park, along a street or past the planting beds of an apartment complex in Japan has probably seen young trees braced with poles and bamboo. These are tree stakes, called shichū. When local governments plant trees in parks and along roads, their standard drawings set out which stake to use for which size of tree and how to assemble it. Using the City of Yokohama’s Standard Drawings for Park and Green Space Facilities and Tottori Prefecture’s tree stake drawings as a guide, I will describe the types of stakes and how they are put together, the handwork that survives in their form, and when to remove them. The illustrations were drawn by our company.

What stakes are for: a temporary structure that keeps the roots still

People tend to think stakes are there to stop a tree from falling over, but their main job is to protect the roots. The Manual of Countermeasures for Tree Failure of Street Trees, 2nd edition (2019) from the National Institute for Land and Infrastructure Management (NILIM) explains that stakes are installed to keep a newly planted tree from falling, and to prevent strong swaying in the wind from opening gaps between the root ball and the planting soil or breaking the fine new roots, so that root growth is encouraged.

A freshly planted tree has simply been set into the ground with its root ball (the mass of roots and soil lifted with it) and has not yet rooted into the surrounding soil. When the trunk moves, the root ball moves too, and the fine roots that have just begun to grow snap with every sway. The stake is there to stop that. The same manual describes stakes as, in principle, a temporary structure that stays only until the tree has established and extended its roots enough to support itself.

Choosing by tree size: the “application tables” in the standard drawings

Which stake to use depends on the size of the tree. Standard drawings classify trees by height and trunk girth and set the form and dimensions of the stake for each class. Tottori Prefecture’s drawings open with an application table that separates planting in parks from planting along roads and shows the stake to use for each girth and height.

For the main stakes, Yokohama’s drawings, Tottori’s table (parks, tall trees of 3 m or more) and the “examples of application conditions” in NILIM’s manual compare as follows.

Even for the same size of tree, the form used differs slightly from one client to another. In Tottori’s table, for trees planted along roads the cross torii is used up to girths of 75 cm and more, and the 4 m cedar yatsugake up to girths under 50 cm, so the ranges differ from those for parks. For medium trees 1 to 3 m tall, the table lists the two-leg torii with splint, the bamboo yatsugake, the soebashira type (a single bamboo set along the trunk), the bamboo nunokake and the hedge stake. On site, we follow the standard drawings of the client for that job.

NILIM’s manual advises considering a stake one grade above the usual specification where trees are exposed to strong winds, such as on the coast or on windswept sites. The figures in the table are guides for standard conditions.

How each type is assembled and installed

From here, the main stakes are shown in drawings. Each illustration shows the stake from the front, with a plan view in the top right. The parts that go into the ground are drawn down to their pointed tips.

Two-leg torii stake: a simple form for narrow planting spaces

Two cedar poles stand on either side of the trunk, with a crossbar across the top tied to the trunk. The name comes from its resemblance to a shrine gate (torii). NILIM’s Guidelines for Typhoon Damage Countermeasures for Urban Greening Trees in Okinawa (2011) describes the torii type as cut poles assembled in the shape of a torii, and notes that its simple form suits sites with little planting area.

In Tottori’s drawing (with splint), two 1.8 m cedar poles are driven into the ground, and a 0.6 m crossbar is set across their tops 0.95 m above the ground, nailed and bound crosswise with wire. The crossbar is tied to the trunk with cedar bark and shuro rope. The splint is a slender cedar top-pole 4.0 m long that runs along the trunk up into the crown and is tied at the crossbar and at a higher point. Yokohama’s drawings also show a torii stake of 1.5 m cedar poles (TS-S) and a version with a bamboo splint (TS-SM).

Gassho stake: legs leaning in from four sides

Yokohama’s drawings use the gassho stake (GS) for trees with a girth of 40 cm to under 70 cm. Four short cedar poles, about 60 cm long, are assembled in a 井 (hash) shape that clasps the trunk from four sides, and four long cedar poles lean in diagonally from four directions to its corners, where they are nailed and wired. The tops of the legs project a little above the frame. The legs lean towards the trunk like hands pressed together in prayer (gasshō).

Yatsugake stake: bamboo or poles from three directions

The yatsugake stake leans three bamboo canes or poles in from three directions, seen from above, and ties them to the trunk. The tie height is 60% of the tree’s height in Yokohama’s drawings and two-thirds in Tottori’s. The three pass beside the trunk and cross each other, with their tops projecting a little above the crossing. Where they meet the trunk they are tied with cedar bark and shuro rope; canes and poles are fixed to each other with wire.

The way the feet are held is the key to this stake. For bamboo, a short piece of bamboo (negase) is driven in at an angle to cross the cane in an X, and is fixed with wire in a saw cut. For cedar poles, Tottori’s drawing has a 0.6 m cedar stake driven in to cross each pole, nailed and bound crosswise with wire. On our sites, the stake crosses the pole at ground level, and the crossing is fixed where it can be seen above ground. The foot does not slip, and loosening is easy to check at inspection.

Yokohama’s three-cane madake stake (MD-3L) is for trees with a girth of 9 to 15 cm. The three-pole cedar stake covers trees from 2.5 m to under 7.0 m tall, in ten grades of pole length (3.0 to 5.5 m) and thickness, and on larger trees the poles are tied not only to the trunk but also to main branches. The Okinawa guidelines say the yatsugake suits trees with a wide crown and sites with a large planting area.

Yagura stake: a framework that holds a large tree

Yokohama’s drawings use the yagura stake (YS) for large trees with a girth of 70 cm to under 120 cm. 3.8 m poles rise from four directions, and their tops are fixed about 3.2 m up to a small hash-shaped frame that clasps the trunk. About 1.6 m above the ground, a square frame of 1.8 m poles links the four legs, and the legs are also tied to main branches on the way up. It looks like the frame of a wooden watchtower (yagura) and is the form you see when a large tree has been transplanted.

Nunokake stake: trees in a row holding each other up

The nunokake stake links a row of trees with a single horizontal bamboo rail. In Yokohama’s reference drawings (MD-NS, MD-NL), a madake bamboo rail runs through a row of trees 1.5 to 3.0 m tall; the left end is braced by two canes splayed outward in a V, and the right end by two canes set at right angles to the row. Tottori’s drawing also runs the rail at two-thirds of the tree’s height. Because the trees in the row support one another, this stake is used for row planting. Nuno is the word for a horizontal member in scaffolding; it appears, for example, in the article on log scaffolding (Article 569) of Japan’s Ordinance on Industrial Safety and Health.

Hedge stake: a frame that resembles a bamboo fence

For a row of young hedge plants, the hedge stake sets two rails of madake bamboo, one above the other, on cedar posts, and each plant is tied to them with cedar bark and shuro rope. In Tottori’s drawing the posts stand every 2 m, the rails are nailed on, and the height is about 1.3 m. Both Yokohama and Tottori specify two to three plants per metre.

There is also a single-cane stake for young trees (Yokohama MD-1, 0.8 to 1.5 m tall), in which one bamboo cane is pushed in at an angle and tied, and the soebashira type in Tottori’s drawings, in which a cane is set along the trunk. NILIM’s manual also lists a wire type that guys the tree from three to five directions, and steel and underground types used where appearance or pedestrian traffic matters.

Bamboo, cedar poles, cedar bark and shuro rope: handwork in the materials and the ties

The notes on the drawings show that the materials are still, in principle, natural ones. In Yokohama’s drawings, madake bamboo is about 2.5 cm at the narrow end, “cut at a node at the tip”, and cedar poles are “untreated”. Tottori’s drawings specify cedar or hinoki cypress poles with preservative treatment (charring excluded). Even for the same cedar pole, the specification differs from one client to another.

Where the trunk meets the stake, it is wrapped in cedar bark and tied with shuro rope (palm-fibre rope). In Yokohama’s drawings the rope is “red (undyed)”, 3 mm in diameter, used doubled, in a crossed “aya-warikake” tie of at least three turns, and poles are joined with nails and wrapped crosswise in the same way with No. 18 galvanised wire. The Tokyo Metropolitan Government’s Standard Specifications for Street Tree Maintenance (Green Space Management, April 2013) require the trunk to be wrapped in cedar bark and tied with shuro rope “crosswise, with no slack”; yatsugake and nunokake stakes to be fitted “at a proper angle, neatly and firmly”, taking wind direction, soil and tree form into account; and the tips of the poles to be “trimmed neatly”. A government specification asks twice for the work to look good. The idea that a stake becomes part of the streetscape along with the tree is written into the specification itself. The Okinawa guidelines say the same: stakes form part of the landscape together with the tree, so materials of a consistent type and colour are preferable.

The drawings give dimensions and materials, and stop there. In my experience on site, the quality of a tie shows less in the number of turns than in how evenly they lie and how firmly they are pulled. Too tight and the trunk is damaged; too loose and the tree sways and the roots break. The tops of the canes are cut just above a node, all level; the tops of the poles are trimmed to the same height. A stake whose finished lines are even looks clean even from a distance. Among craftsmen it is sometimes said that you can judge a gardener’s skill by his stakes.

At Jushoin, a temple in Edogawa, Tokyo, where we care for the pine known as Garyu-no-Matsu (the “reclining dragon pine”), we renovated the stakes in 2023. We removed the horizontal poles and bamboo that had linked branch to branch, reinforced the branches instead with hōzue props that brace each branch diagonally from below, and replaced deteriorated poles with charred poles treated with preservative (Tanalith). Poles and bamboo were bound closely with shuro rope, and the bamboo, which deteriorates in about three years, is replaced as needed. The fewer stakes there were, the more the pine’s own branch structure came into view.

A history of stakes: forms passed down in government drawings, and new types

When and where did the practice of holding up trees with bamboo, cedar poles and shuro rope begin? I looked into it, but this time I could not find a primary source that clearly shows the origin of tree staking. What I do not know, I will leave as unknown.

What can be confirmed is how recent government standards have developed. Yokohama’s website publishes past editions of its Standard Drawings from the April 1999 edition onward, revised in 2002, 2005, 2009, 2013 and 2018; the April 2018 edition is still in use with partial revisions. Tottori Prefecture and the Tokyo Metropolitan Government also set out the forms and ties of stakes in their own drawings and specifications. NILIM’s manual states that stakes using bamboo or timber are the basic and most widely used type, and then lists steel stakes using steel pipe and underground stakes that anchor the root ball below ground, for sites where appearance or pedestrian traffic matters. For underground stakes, it adds that the tying material should be confirmed to be degradable so that growing roots do not become girdled by the fixings.

Famous and old trees may also have permanent supports, separate from the temporary stakes used at planting. NILIM’s manual says permanent stakes are needed for trees that are constantly exposed to strong winds, or that grow in small planting bases where the roots cannot extend enough. The Garyu-no-Matsu at Jushoin is said to be more than 500 years old; its trunk broke in a great wind in the Taisho era (1912–1926), leaving the low, creeping form it has today. For a tree like this, the stakes become a tool that goes on supporting its form. Abroad, cabling (crown securing), in which branches at risk of splitting are tied to each other with rope, is also widely used, and we install it as well.

When to remove stakes, and re-tying: so that stakes do not harm the tree

Because stakes are temporary, there is a time to take them off. NILIM’s manual gives roughly three to five years after planting as the guide for removal, pointing to the time when wooden stakes are deteriorating or when they are likely to begin cutting into the trunk (from about five years on). It also warns that if stakes are left after the tree has established, they can girdle and damage the tree, and a rotten stake itself becomes a hazard.

The City of Yokohama Road Bureau’s Common Specifications for Street Tree Maintenance Contracts (February 2026) give the purposes of re-tying as preventing the tied part of the trunk from becoming constricted and prone to breaking as the trunk thickens, and restoring the function of a stake lost when shuro rope and other materials rot. For removal, the stake is pulled completely out from the base, all ties including shuro rope and wire are removed, and the hole is backfilled and levelled.

In tree assessment work, too, we sometimes come across trunks pinched where an old stake rope has cut into them. Perhaps the inspection a few years later matters more than the day the stake goes in.

A stake is a tool that holds a tree for the few years until it can stand on its own roots. Put it up neatly and firmly; when its work is done, take it off before it harms the tree. Only when both are done, I believe, is the job of staking finished. For inspection, re-tying or removal of tree stakes, please contact us at info@toshilandscape.co.jp or through our contact page.

Frequently asked questions

Q1. When should tree stakes be removed?

A. Stakes put in at planting are generally removed about three to five years after planting. NILIM’s Manual of Countermeasures for Tree Failure of Street Trees (2nd edition) points to the time when wooden stakes are deteriorating or are likely to begin cutting into the trunk (from about five years on). Trees constantly exposed to strong winds, or growing in small planting bases where the roots cannot extend enough, need permanent support.

Q2. What types of tree stakes are there in Japan?

A. The two-leg torii stake (two cedar poles and a crossbar), three-leg, cross and four-leg stakes with more legs, the yatsugake stake (three canes or poles from three directions), the nunokake stake (a horizontal bamboo rail linking a row of trees), the gassho stake (poles leaning in from four sides), the yagura stake (a frame and poles for large trees), the hedge stake (young hedge plants tied to two bamboo rails), and the single-cane and soebashira stakes for young trees, among others. There are also steel, underground and wire types.

Q3. How is a stake chosen for the size of the tree?

A. Standard drawings classify trees by height and trunk girth and set the stake for each class. In Tottori’s table, for example, tall trees in parks with a girth under 30 cm get a two-leg torii with splint, and those of 30 to 60 cm a three-leg or cross torii. Because the form used for the same size of tree differs from client to client, on site we follow the client’s standard drawings for that job. Where strong winds are likely, a stake one grade higher is considered.

Q4. What should be done if the stake rope is cutting into the trunk?

A. Re-tie it, or remove the stake if it is no longer needed. Yokohama’s specifications call for re-tying to prevent the tied part from becoming constricted and prone to breaking as the trunk thickens, using new cedar bark and shuro rope. When removing a stake, all the ties should be taken off as well.

Q5. Why are cedar bark and shuro rope used to tie stakes?

A. Tokyo’s and Yokohama’s specifications call for the trunk to be wrapped in cedar bark where it meets the stake, to protect the bark, and then tied with shuro rope with no slack. The Okinawa guidelines say that because stakes are part of the landscape, materials of a consistent type and colour are preferable. Cedar bark and shuro rope deteriorate, so a guide for when to replace them should be set.

Sources

• City of Yokohama, Green Environment Bureau. Standard Drawings for Park and Green Space Facilities, Chapter 2 Planting and S2 Reference Drawings (April 2018 edition, partially revised April 2024). Past editions from April 1999 are on the same page. (Japanese)
• Tottori Prefecture. Tree Stakes for Planting, Chapter 7 Planting Work, 7-1 to 7-7 (application table, rear, side and plan views of each stake, materials table). (Japanese)
• National Institute for Land and Infrastructure Management. Manual of the Countermeasures for Tree Failure of Street Trees, 2nd edition. Technical Note No. 1059, February 2019, pp. 1-61 to 1-64 (Table 2.9, examples of application conditions for stakes), 1-87 to 1-89. (Japanese)
• National Institute for Land and Infrastructure Management. Guidelines for Typhoon Damage Countermeasures for Urban Greening Trees in Okinawa. Technical Note No. 621, 2011, section 1.5 Stakes. (Japanese)
• Tokyo Metropolitan Government Bureau of Construction. Standard Specifications for Street Tree Maintenance (Green Space Management), April 2013, sections 2-2-10 and 2-2-11. (Japanese)
• City of Yokohama Road Bureau. Common Specifications for Street Tree Maintenance Contracts, February 2026, Chapter 8, Articles 55–58. (Japanese)
• Ordinance on Industrial Safety and Health, Article 569 (log scaffolding). (Japanese)

Masatoshi Nakamura
Jumokui (Tree Doctor), Toshi Landscape Co., Ltd., Tokyo