Structure and rigidity

The structural roots play the same role in the soil as do the branches above ground. The branches hold the leaves, and the structural roots do the same for the rootlets responsible for extracting nutrients and water. The branches are rigid in order to counter gravity, while the structural roots have to anchor the tree firmly so that it can remain standing. The structural roots and branches work together to give the tree a functional rigid structure.

The taproot, the first root to sprout from a seed, grows downward. In conifers, it disappears quickly after germination. In broadleaf trees, the taproot's lifespan and importance vary depending on the species.