How can i detect a collision to add score?

Question

When my player touches the object, it should add score but does not go. I put this code on the tree. Thanks!

public class LifeTree : MonoBehaviour
{   
    private int contador=0; 
    private ScoreData _scoreData; 

    private void OnCollisionExit(Collision other)
    {
        if (CompareTag("Player") & contador < 4)
        {
            _scoreData.score = _scoreData.score+5;
            Debug.Log("Tree"); 
            contador++;   
        }
    }
}

Answer 1

So first make sure a rigidbody is attached so a collision can be recognized.

void OnCollisionEnter(Collision col)
{
  if(col.gameObject.tag == "Player" && contador < 4)
  {
    //detects if the player hit the tree
  }
}