How can I make a GameObject that has a health bar?

I am trying to make a survival game but I can’t figure out how to make it so my character can destroy objects with tools/fists. I am making C# files for each destroyable GameObject, heres my first one:

using UnityEngine;
using System.Collections;

public class BigTree : MonoBehaviour {

	int Health = 100;


	// Use this for initialization
	void Start () {
	

	}
	
	// Update is called once per frame
	void Update () {
	
		if(Health == 0) {
			Destroy (gameObject)

		    }
		}
	}

By the way, I just started messing around with Unity so my code is probably totally wrong.

There’s a bunch of stuff that needs to be worked out here, such as how you’ll decrement the private int Health, what “damages” the BigTree and by how much, what if Health goes from 12 to -3 (ie. use <= 0 instead of ==0), etc.

I suggest a good tutorial vid @
http://www.unity3dstudent.com/get-help/