Tree Chopping/Harvesting cooldown

So i made a tree "harvesting" script and i want to have a cooldown for it. I dont want the player to be able to spam the button and get Wood and Exp from it. I'd like to have an cooldown system so i can Harvest and wait for 10 seconds and harvest again after the 10second cooldown. But i cannot find anything like this anywhere so im asking help here. Sorry for bad grammar, english is not my native language.

Code =

 #pragma strict
 
 var TreeHarvest : boolean = false;
 var menuSkin : GUISkin;
 public var Player : GameObject; 
 private var InventoryScript : Inventory;
 private var ExpScript : ExpSystem;
 var canHarvest : boolean = false;
 
 function Start () {
 
 }
 
 function Update () 
 {
 
 }
 
 function HarvestTree () 
 {
     InventoryScript = Player.GetComponent(Inventory);
     InventoryScript.wood += 1;
 
     ExpScript = Player.GetComponent(ExpSystem);
     ExpScript.Exp += 1;
 }
 
 function OnTriggerEnter (other : Collider)
     {
         if(other.tag == "Tree") {
             TreeHarvest = true;
         }
 }
 
 function OnTriggerExit (other : Collider)
 {
     if(other.tag == "Tree"){
         TreeHarvest = false;
     }
 }
 
 function OnGUI ()
 {
     if(TreeHarvest == true)
     {
         GUI.skin = menuSkin;
         GUI.BeginGroup(new Rect(Screen.width / 2 - 150, Screen.height / 2 - 150, 300, 300));
         GUI.Box(Rect(0, 0, 300, 300), "Tree Harvesting");
     if(GUI.Button(Rect(60, 50, 20, 20), "Harvest Tree" ))
     {
         if(canHarvest == true) {
             HarvestTree();
         }
     }
 }

}