THE SANCTUARY ESTATEgardens
How it works

A river that runs uphill.

When sunlight warms a leaf, water evaporates inside it and slips out through tiny pores. Each molecule that leaves tugs on the next, because water clings to itself, and the tug runs down an unbroken thread through twigs, limbs, trunk and roots to the finest root tips. The whole column rises. Two scientists in Dublin, Henry Dixon and John Joly, proposed this in 1894, and more than a century of measurement has borne them out.

Four kapoks grow in the gardens; the first were planted in 2015. The same river runs through each of them, every sunny day.

Reading the drawing

  • Blue is water, climbing in the dead pipes of the wood.
  • Gold is sugar, coming down in the living pipes under the bark.
  • Teal threads are fungi, the hidden partners around the root tips.

Below ground the depth is stretched so you can see the roots: almost all of a kapok’s roots lie in the top meter of soil, running out past the edge of the crown, with a few sinkers and a taproot going deeper. The building counts twenty floors of three meters. The water moves thousands of times faster here than in life.

Four more

  1. Florists recut flower stems under water. Cut in air, the stretched thread of water snaps back and air rushes into the pipes, blocking them.
  2. When a thread of water breaks under too much pull, it clicks. Botanists have recorded those clicks with microphones since the 1960s.
  3. In the laboratory, pure water has held a pull of about 250 atmospheres before breaking, more than ten times the pull at the top of a tall tree.
  4. Kapok wood is so light that a block of it weighs about a quarter as much as the same block of water.

Where the numbers come from

A kapok spends nothing to lift its water. The sun does the work, and the tree lets go of almost all of it.

How the kapok grows: Above and belowThe kapok in the collection
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