Hawaiian
Ethnobotany-Anatomy-20 
Hawaiian
Ethnobotany-Anatomy-20 
Secondary Growth-3
The Outer Bark (Cork or Periderm) is produced by the Cork Cambium.
Cork Cells comprise the Outer Bark.
| Cork production
begins when cells just beneath the Epidermis divide parallel to the surface. There is a unicellular layer which continues to produce Cork cells towards the outside of the stem. This is the Cork Cambium. Cork cells have waxy cell walls and die at maturity. This isolates the Epidermis and results in its demise. The waxy walls provide a barrier to water loss and pathogen attack. Cork also has insulating properties and was used commercially before the age of Styrofoam |
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Link to Periderm
Development |
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Spanish Cork Oak is the source of commercial Corks. Thick bark also protects plants from range fires and other environmental insults. |
 External view of the Bark from Spanish Cork Oak |
 Diagram showing showing the Outer Bark (Cork), Inner Bark (Secondary Phloem) and Wood (Secondary Xylem) |
 Stump of Norfolk Island Pine (Araucaria) showing the Outer Bark (Cork), Inner Bark (Secondary Phloem) and Wood (Secondary Xylem) |
The Outer Bark is produced by the Cork Cambium. It is dead at maturity and forms a barrier between living tissues inside the plant and potentially lethal components of the environment. The Outer Bark is what we commonly mean when we say bark. However, there is also an The Fibers of the Inner Bark are longer and more uniform than those produced during Primary Growth (Primary Phloem [Bast] Fibers). It is the Inner Bark Fibers of wauke & hau which are harvested for kapa and cordage. |
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 Metasequoia produces a thick Bark & reaches great heights. |
 Secondary Phloem with Secondary Phloem Fibers from hau stem with polarized light. |
 Sequoia trees have a lot of Secondary Growth. |
 Giant Sequoia |
