|MadSci Network: Botany|
Not being from the land down under I would assume your question deals with the death of a tree because the bark is removed. Spending a great deal of time as a Boy Scout, and planting new trees where there was damage to a forest due to clear cutting, it was not unusual to see new sprouts from the old trunks. On cloaserinspection, I also noticed the ones further from the tree were also seedlings produced from the main tree's seeding.
The new sprouts you mention are called water sprouts. Also the term "suckers," or shoots that appear near the base of a main stem or in your observation around the trunk. In the living tree they may divert energy and are usually removed by pruning.
Now, if I understand, in ring barking some of the bark is removed from the tree in a circle around it. When this is done it exposes the phloem and xylem tissue to the outer environment and damages it. Many things can interfere with the tree's ability to carry nutrients to other parts of tree - from the roots and food from the leaves to the roots for growth if these transportation tubes are cut or damaged. It would be like ripping through the veins and arteries of a human being. When the tree dies, it will shoot off suckers and water sprouts. These could grow into small branches or offshoots of the tree, some growing large but not a straight and even growth as a seedling would grow. In the ring barking, you then have actually destroyed the protective covering of the tree. The tree becomes exposed dried out and rots. Insects would damage it further until it dies.
David Hershey adds the following:
Harris (1983) notes that ring barking or girdling a year or two before the tree is cut down tends to inhibit stump sprouting compared to just cutting the tree down. Possibly this is because ring barking does not kill the tree, just disrupts the phloem which prevents sugars produced by the leaves from reaching the roots. Using stored nutrients, the root system continues to absorb water and mineral nutrients that it translocates to the shoots via the xylem. Eventually, the root system starves and dies. If the tree was not cut down until after the root system was dead, then there should be no stump sprouting.
Obviously, this technique is not perfect because it takes a year or two and does not prevent sprouting from below the girdle during that one or two year period.
Harris, R.H. 1983. Arboriculture. Englewood Cliffs, NJ: Prentice-Hall.
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