The past tense of tree is treed.
Adding -ed makes a verb a past tense verb. This means the action happened in the past. ie. I climb a tree. (present tense) Yesterday, I climbed a tree. (past tense)
The simple past tense of "hide" is "hid." For example, "She hid behind the tree."
The monkeys were sitting on the tree.
saw. Today, I see a tree. Yesterday, I saw a tree.
Past
If 'hung it up on the tree' is in the past tense, as in 'He hung it up on the tree!', it is correct. If it is in the present tense, then, no, it is incorrect. In the present tense, the correct way of saying it would be, 'hang' or 'hangs', not 'hung'.
If you are speaking of the noise made by animals such as dogs (and some humans), the simple past tense is barked. The verb bark can also refer to the removal of the bark from a tree. That simple past tense is also barked.
The past tense of "pick" is "picked." In English, regular verbs typically form their past tense by adding "-ed" to the base form of the verb. "Pick" is a regular verb, so it follows this rule. For example, "Yesterday, I picked some apples from the tree."
Felt is a word. It is a noun and also the past tense of feel.
the past tense of am is was and the past tense of has is had
The past tense of "has" is "had" and the past tense of "have" is "had."
Built is a past tense adjective, "the house is built." Build is a verb "please build me a house."