It is possible to cut down a tree on your property yourself, but it is generally not recommended unless specific conditions are met. You should only consider this project if the tree is small (e.g., under 4-5 inches in diameter and short enough that you don't need a ladder to reach the branches), and you are experienced in handling a chainsaw. The tree must also be located far from any power lines, fences, homes, or other structures. Even for small trees, the work can be dangerous, and it's always advisable to have a spotter to ensure the tree falls correctly and no branches fall on you.

For any tree that is large, requires a ladder to access, or is near electrical lines or structures, you should always hire a professional. Attempting to remove a large tree yourself is extremely dangerous, poses a risk of serious injury, and could result in significant damage to your property.

Before any tree removal, it's also important to check your local and state regulations to ensure the tree is not historic or otherwise protected by your city.

Since each tree is different, it’s impossible to say how long a dead tree can remain on your property. While it could be days, months, or even years, it’s highly likely that, at some point, the tree will fall. In the meantime, dying or dead trees can become a haven for pests, so it’s best to have them removed sooner rather than later.

If a disease has attacked and destroyed the roots, then the tree may fall over as soon as it has died or while part of it is still alive. Trees that die with their roots left in place tend to stay standing for much longer, but those roots will decay eventually, allowing gravity to do the rest.

Since overwatering can harm mature trees just as much as a lack of water, it’s important to know the signs of an overwatered tree. If your tree’s leaves are yellowing, wilting, or dropping leaves, it’s likely that you’re overwatering. Other common signs include rotting, fungi, soggy soil, soft or peeling bark, falling leaves, and brittle roots. 

If you realize that you’ve been overwatering your mature tree, stop watering and give the soil time to dry out. Then moving forward, increase time between watering sessions.