It can be bad to leave a dead stump in the ground. A stump becomes a hefty piece of dead wood in time and eventually (especially with the help of rain) starts to rot. That makes it a locus point for diseases and pesky insects, as well as a bit of an eyesore. It’s best to remove a tree stump completely before it starts to decay, especially before it starts to fall apart. If the tree was removed because of disease, it’s even more important to fully remove the stump if possible.

Leaving the tree stump and letting it rot is never a good idea, as this leads to insect infestations and other frustrations. Additionally, decomposing trunks are at risk for diseases that spread out to the remaining plants and trees in the yard, thus ruining your whole outdoor aesthetic. It's usually best to remove the stump at the same time you remove the tree.

There are several signs that may indicate a tree needs to be cut down. These include visible damage to the trunk or branches, a hollow trunk, extensive storm damage, or a significant lean to one side. Other warning signs are pest infestations or the tree growing too close to a house, power lines, or other structures. It is best to hire a professional arborist to inspect the tree, as they can determine if it can be saved or if removal is necessary.

Yes, tree roots can regenerate after they’re pruned or cut. In fact, trimming can stimulate new growth, especially in healthy trees. The tree’s roots can still grow back even after a tree is cut down, (and learning how to get rid of regrowing tree roots is a separate feat). Still, if you don’t wish to harm a tree, pruning the roots should be done with extreme care, and ideally by a professional.