When your tree starts to look a little worse for wear, it can be tempting to hire a professional tree service to come and take a look. However, this is not always necessary. There are a few things you can do to try and resurrect your tree without spending a lot of money.
First, take a look at the roots. If they are dry or dead, then there is not much you can do. However, if they are still alive, then you need to water them. Deeply water the roots once a week for best results.
Next, take a look at the leaves. If they are yellow or brown, then they are probably not getting enough sunlight. Trim any branches that are blocking sunlight from reaching the leaves.
Finally, fertilize your tree. You can buy tree fertilizer at most hardware stores. Follow the instructions on the package.
If you follow these steps and your tree does not improve, then you may need to hire a professional.