What tree is considered a symbol of wisdom?

It depends on the culture. If we are talking about the so-called "Western" culture having its roots in Ancient Greece - it is the Olive Tree. It symbolizes not only wisdom, but also peace, and in the past it also symbolized fertility.
In Poland, I encountered the attribute of wisdom to Oaks. These grow patiently and consistently, reaching impressive sizes over time, and here I would look for the origin that associates them with wisdom.

At first I thought of oak. Maybe because the oldest trees in our country are oaks, and old age is associated with wisdom. Olive trees grow even longer, so it's no wonder that in the Mediterranean zone they have become a symbol of wisdom. However, I have come across one more type of tree that is considered a symbol of knowledge - the fig tree. According to ancient writings, Hippocrates taught his students under a fig tree. Nevertheless, I do not think that in countries that have been in the circle of Christian culture for centuries, there could be a change in symbolism, because the fig tree is associated rather with the proverbial fig leaf, which Adam and Eve covered themselves in paradise, and not with wise behavior ;)

This is neither a philosophical nor a botany question. It fits in the fortune telling and horoscopes section.

In many cultures and traditions, the oak tree is considered a symbol of wisdom. The oak is associated with wisdom because of its longevity, strength, and stability. Its roots reach deep into the ground, symbolizing a strong connection to tradition and the past. Additionally, the oak tree bears abundant fruit, which can be interpreted as abundance of knowledge and experience. In ancient Roman mythology, the oak tree was dedicated to the god Jupiter, who was considered the god of wisdom and justice.