how to make gameobject jump onto other gameobject using Linecast

Hi so what im trying to make is a tree falling over across a gap and the character is always moving forward. Once he hits the tree, i want him to jump once onto the tree and continue across.

Here's a sample of my code. I am fairly new to Unity and to coding, so any tips would be much appreciated.

using UnityEngine; using System.Collections;

public class CharacterControl : MonoBehaviour {

 Animator anim;

 public float speed;
 public Transform sightStart, sightEnd, groundedEnd;
 public bool treeHit = false;
 public float thrust;
 public Rigidbody2D walkForce;
 public bool grounded = false;

 RaycastHit2D treeJump;


 bool jumped;
 
 // Use this for initialization
 void Start () {
     walkForce = GetComponent<Rigidbody2D>();
 }
 
 // Update is called once per frame
 void Update () 
 {
     walkForce.AddForce(2*Vector2.right);

     Raycasting();

     
 }
 void Raycasting()
 {
     Debug.DrawLine(sightStart.position, sightEnd.position, Color.green);
     Debug.DrawLine(this.transform.position, groundedEnd.position, Color.green);


     if (Physics2D.Linecast (sightStart.position, sightEnd.position, 1 << LayerMask.NameToLayer ("Tree"))) {
         treeHit = true;
         walkForce.AddForce (Vector2.up * 10f);
     }
     if (treeHit = true) {
         treeHit = false;
     }
     }

}