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I was wondering how trees grow. I wonder if it was similar to hair growth which occurs from the follicle. but clearly branches grow from the trunk so there is definitely a difference with hair growth.
I looked here and couldn't find a verifiable source, there are contradicting answers.
If I carve and inscription in a young tree, will it get up with time?
It appears you are mostly interested in the vertical growth of trees. As @Joe Healy points out, this is done only by cells in the apical meristem. This region always remains at the top tip of the tree, that is where the upward growth occurs. The apical meristem, as it continues upward with growth, will leave portions of itself behind that may result in branches (axillary merristems). So yes, unless you carve at the very tip of the tree, your initials will remain at the same height you carved them.
A very simple experiment that I've done many times with students demonstrates this. Germinate some corn seeds until the shoot and the root are about 2 cm long. With a fine Sharpie, mark each with lines every 4 mm or so. Continue the germination. After a few more days you'll note that the line spacings nearest the kernal are the same as when you drew them. But on the very outboard end, near the tips of shoot and root, the spacing will appear stretched out.
Another type of meristem, the vascular cambium, is responsible for the increase in diameter of a tree. It is a sheath that lies between the bark and wood producing new wood to the inside and new bark to the outside.
Yes in general a tree's primary direction of growth will be from the tip of a new shoot, though not exclusively (for instance the additon of new tree rings occurs from the inside out.
Most growth occurs at the apical meristem of a new shoot as cells continually push outward.
