Technique paper 秋 · Autumn
Jin and shari: carving deadwood without cutting the live vein
- Season
- Late autumn to winter, when the tree is not pushing growth
- Risk level
- High — cutting into a live vein can kill the tree within one season
- Steps
- 7
- Bark per session
- No more than 30 percent of the remaining bark in one session
- Wait between sessions
- One full growing season
Cultivation record
Tools
- Hand pull-shave and a rotary tool with 4 to 8 mm burrs
- Wire brush and a stiff nylon brush
- Lime sulphur, diluted to 15 to 20 percent
- A soft brush for applying lime sulphur
Risk level：High risk · 7 steps
Deadwood work is the most permanent thing you can do to a tree. A wiring mistake grows out in two seasons; a carve that crosses the live vein is visible for the rest of the tree's life, if the tree has one. The whole method is about finding the vein first and never crossing it.
Find the vein before you find the chisel
A juniper's life runs in a strip of cambium usually between 8 and 25 mm wide, running from a root up to a branch. Everything else on the trunk can be dead. The vein is easiest to find in winter: spray the trunk with water and watch. The vein soaks the water in and darkens; dead wood beads it and stays pale. On this project every carving plan is drawn on a photograph with the vein traced in pencil first, and the pencil line is treated as a hard boundary that no tool crosses.
The 30 percent rule and why sessions are a year apart
Removing bark removes the tree's ability to move water through that section of trunk; the remaining vein has to carry the whole crown. Taking more than about 30 percent of the remaining bark in one session overloads the vein and shows up as branch dieback the following summer. The reason for waiting a full growing season between sessions is that the tree has to grow a new layer of wood under the carved surface to seal it, and that takes one season on a healthy juniper. Two sessions a year apart is aggressive; one session every second year is conservative and produces a better surface.
Making deadwood look old
Freshly carved juniper wood is pale, soft and obviously new. Three things age it: carving along the grain with a wire brush to raise the harder summer wood and leave the softer spring wood recessed; hollowing the interior so that shadow does the work; and lime sulphur applied in shade, never in direct sun, because sun on wet lime sulphur bleaches unevenly and leaves a streaked surface. A 15 to 20 percent dilution applied in February and repeated every other winter produces the grey-white that reads as weathered.
What not to do
Do not carve wet wood in summer. Do not seal deadwood with varnish, wood hardener or lacquer — it traps water and rots from the inside. Do not connect a shari to a jin with a carved channel narrower than 5 mm, because it will look like a scratch rather than a natural feature. And do not carve a tree in the same season it was repotted; the tree needs all its resources for the roots.
Steps in order
- Trace the live vein in winter by spraying the trunk with water and watching where the water beads and where it soaks in.
- Mark the planned shari with chalk on the dead side only, keeping at least 8 mm of clearance from the traced vein line.
- Remove bark in strips with a hand pull-shave, working along the grain and never across it.
- Hollow the deeper areas with a rotary burr, but stop 3 mm short of the vein; leaving a thin wall of dead wood protects it.
- Raise the grain with a wire brush in the direction of the wood fibres, then soften the edges with a nylon brush.
- Apply lime sulphur at 15 to 20 percent in February, in shade, and leave to dry for 48 hours without wiping.
- Wait a full growing season before carving further, and check the vein for any sign of recession before the next session.
What to remember
- Trace the live vein with water in winter and treat the traced line as an absolute boundary.
- Remove no more than 30 percent of the remaining bark per session, one session per growing season.
- Apply lime sulphur in shade at 15 to 20 percent; sun on wet lime sulphur streaks the surface.
- Never seal deadwood, and never carve in the same season as a repot.
Note Growing notes are provided for general information only. Lime sulphur is a caustic preparation; wear gloves and eye protection and follow the label.