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A nail is inserted into a tree's trunk at a young stage of its development. At which height will we find the nail after some years? Will it be found higher or at the same height(What extent of accuracy?) as when it was inserted? I have two specific questions:

  1. Doesn't the intercalary meristem, which is responsible for the increase in internode length, affect the relative position of the nail?

  2. When plants are at a young stage their branches' position would be low but after some years they would have moved higher. How does this happen if growth only happens in the apex? As an example, in the following image the position of the branches changes with time. Why wouldn't the same happen with a nail?

Groeth of branch position

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  • $\begingroup$ Welcome to Biology SE! I have suggested an edit of your question in an attempt to make it more cleear. Feel free to roll-back the changes if you do not think it was useful. $\endgroup$ – vkehayas Dec 13 '17 at 13:27
  • $\begingroup$ One cell at a time. $\endgroup$ – aaiezza Dec 13 '17 at 21:32
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You will find the nail at the same height. Trees grow by a) adding to the tips of their branches (sometimes sprouting new branches at nodes), and 2) adding to their diameter. (Only a thin layer inside the bark actually grows, forming the annual growth rings.)

The branches changing position in your image is an illusion. The branches do not actually move. What happens is that the higher branches grow larger, shading out lower ones, which die (or become leafless support branches). You can see this most obviously in many conifers, where the dead lower branches tend to remain on the trunks. If you cut and split a trunk, say for firewood, you will find knots in the wood where the older, now dead, branches were once attached.

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  • $\begingroup$ Nice answer. It would be even better if you included some references. $\endgroup$ – RHA Jan 13 '18 at 4:34
  • $\begingroup$ @RHA: If you want references, feel free to add some. I don't have any, other than high school biology and spending a lot of time observing trees. As for instance signs & wire fences nailed to trees. Decades later, they're at the same height, but the tree bark has grown around them. $\endgroup$ – jamesqf Jan 13 '18 at 5:01

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