Interested in identifying trees in your area, but not an expert? There are several apps and websites that you can use to give it a go!
A good online key for urban spaces in California is Urban Tree KEY from the Urban Forest Ecosystems Institute at Cal Poly San Luis Obispo https://urbantreekey.calpoly.edu/.
There are a variety of apps that can be found for your Apple or Android device if you search for a tree identifier. Make sure to look for the app that best suits your geographical area and environment (natural or urban setting) to improve your chances of success.
Some examples for Android devices include, but are not limited to:
PlantNet Plant Identification is a fantastic resource to help you narrow your identification simply by taking a detailed photograph of the leaves, flowers, or fruit.
Virginia Tech Tree ID
NCFS Tree ID App (From the North Carolina Forest Service)