I'm not sure if the process of tension wood formation will stop once teinsion wood has been formed or it's like as long as the tree is bending this process keeps running all the time. Your opinoins are very welcome.
I think tension wood is created when then tree is bending. As soon as the tree is not bending, I belive is creating normal wood. This the case if the tree is bending because of gravity, is it's wind responsable of bending, more dificulte to conclude…
Tension and compression wood are subtypes of the so called reaction wood. Formation of reaction wood is related to mechanical stress. Sachsse (1965) demonstrated that tension stress is directly associated with tension wood formation (in poplars forced to lean over). Interestingly, tension wood, but not compression wood, is often found in roots.
Reaction wood formation occurs only during the period of bending. It's mechanical function is not usefull when stem is straight. On cross-section you can observe one or several reaction wood crescents corresponding to different periods of bending. According to a given type of reaction wood, you can determine on which side the stem had bend during a period. Thus, reaction wood formation process occurs only when stem is bended (bending period is high variable). Moreover, it's more interesting for trees to produce only sufficient amount of reaction wood, because it had been shown that reaction wood is less efficient in conduction, and become inactive earlier than normal wood. For a good review and synthesis about reaction wood, look at this book:
http://www.springer.com/life+sciences/forestry/book/978-3-642-10813-6
Reaction wood occurs when permanent loads produce bending in the tree or when the deviation of the natural growth is possible (hindrance for instace)
My results showed that the production of tension wood starts immediately (within a few days) after bending stress.Trees produce only sufficient amount of TW, till their straightness is recovered.
If bending was continued thus the new straight growth would be in normal direction and TW production due to bending would stop.
This is not to forget the internal stresses of trees which lead to produce reaction wood even in straight trees. Some Genus are more susceptible like: Poplars and Eucalypts.
My understanding is that the formation of the reaction wood by the vascular cambium, during the process of secondary xylem tissue differentiation, is a response to the force of gravity rather than to the mechanical forces of compression or tension (see: MH Zimmerman & CL Brown:Trees Structure and Function 1975ed). Therefore in a continually inclined (e.g. by force) dicot and conifer tree trunk I would also expect continuous formation of RW. Leaning monocots with tree growth habit (e.g. Dracaena draco) have no ability to deposit, in their vascular bundles, RW.
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