Tree nuts are usually cross-reactive. This means that if you are allergic to one type of tree nut, you should try to avoid them all.
Often times, people with peanut allergy are not allergic to tree nuts. Peanuts are not considered tree nuts because they are legumes and grow in the ground. However, if you have a tree nut allergy, you may want to also avoid peanuts because they may be processed on the same equipment.