A family tree is a chart or diagram representing family relationships in a conventional tree structure. Extending over several generations of the family, it is basically a record of the people, places, and events that make up your family history.

Creating a family tree is important because it:

Family memorabilia on the other hand, refer to the keepsakes that have been handed down through generations. They can include anything as simple as ticket stubs to even letters and photos from your loved ones, and are basically objects that have special significance to you and your family.

Family memorabilia are important because they are:

Family History: The importance of telling your story to keep family history alive.
What Makes Genealogy So Important? | AF-213
How to sort memorabilia | Kacy Paide, Professional Organizer DC/MD/VA