Why ring-barking a tree will kill it

Ring barking is the removal of the bark of a tree in a strip all the way around the trunk.

In many tree species this will cause the tree to die. The reason for this is that when bark is removed the whole outer living part of the tree trunk is removed. This includes the vascular cambium, the secondary phloem and the periderm. The tree is unable to produce more secondary phloem in the region where the cambium has been removed. The transport of organic molecules produced by photosynthesis in the leaves to the roots is thus interrupted. Without the organic molecules from the leaves, the roots cannot produce energy-rich ATP by cellular respiration which they use as fuel to run their metabolism, and they slowly begin to die. The tree can no longer absorb the nutrients it need from the soil and the whole tree dies.

What about cork! Cork is produced from the cork oak (Quercus suber) which has very thick bark and it is grown especially in the western Mediterranean. The bark is used to produce corks and is stripped from the trees. The bark is harvested every 10 years, from when the trees are 20-25 years old. The cork breaks away from the tree at the phellogen (cork cambium), thus the process does not kill the tree as the vascular cambium and secondary phloem is left intact and the cork cambium can form new layers of phellem or cork.

NOTE : The bark of many trees is believed to have medicinal properties. It is harvested and sold as medicine. It is very important that the the bark is collected in a responsible manner because if the tree is ring-barked it is likely to die. 

ringbark.jpg (29171 bytes)       corktree.jpg (25508 bytes)
A tree which has been ring- barked
      Cork oaks (Quercus suber) from which the phellem or cork has been harvested.

 

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