How do tress get wider without actually moving upward from the base?

Question

I was pruning trees in the yard and realized that earlier, lower cut branch’s are relatively in the same spot.

My expectation was that trees grew upward from the ground but then I noticed they grow from the top or ends, outward or towards sunlight.

Which lead me to wonder, how do trees actually get wider at the base without growing upward?

In: 3

Answer 1

There’s a layer of cells under the bark that grows both outwards to make more bark, and inwards to increase the diameter of the tree, the growth rings of a tree are laid down year after year in layers, building up the thickness.