Unity3D Add Colliders To Terrain Details, Mouse Click To Remove Terrain Details

AddColliders.cs

using UnityEngine;

public class AddColliders : MonoBehaviour

{
    public Terrain terrain;
    private TreeInstance[] _originalTrees;

    void Start()
    {
        terrain = GetComponent<Terrain>();

        _originalTrees = terrain.terrainData.treeInstances;

        for (int i = 0; i < terrain.terrainData.treeInstances.Length; i++)
        {
            TreeInstance treeInstance = terrain.terrainData.treeInstances[i];
            GameObject box = GameObject.CreatePrimitive(PrimitiveType.Cube);
            box.tag = "Plant" as string;

            BoxCollider boxCollider = box.GetComponent<BoxCollider>() as BoxCollider;
            boxCollider.center = new Vector3(0, 30, 0);

            DestroyablePlant plant = box.AddComponent<DestroyablePlant>();
            plant.terrainIndex = i;

            box.transform.position = Vector3.Scale(treeInstance.position, terrain.terrainData.size);
            box.transform.parent = terrain.transform;
            box.GetComponent<MeshRenderer>().enabled = false;
        }
    }

    void OnApplicationQuit()
    {
        terrain.terrainData.treeInstances = _originalTrees;
    }
}

DestroyablePlant.CS

using System.Collections.Generic;
using UnityEngine;

public class DestroyablePlant : MonoBehaviour
{
    public int terrainIndex;

    public void Delete()
    {
        Terrain terrain = Terrain.activeTerrain;

        List<TreeInstance> plants = new List<TreeInstance>(terrain.terrainData.treeInstances);
        plants[terrainIndex] = new TreeInstance();
        terrain.terrainData.treeInstances = plants.ToArray();

        Destroy(gameObject);
    }
}

DetectCollider.cs

using UnityEngine;
using UnityEngine.UI;

public class DetectCollider : MonoBehaviour
{
    public DestroyablePlant destroyablePlant;

    public GameObject cam;

    public Text queryNameText;

    void Update()
    {
        RaycastHit queryName;
        Ray ray = Camera.main.ScreenPointToRay(Input.mousePosition);

        if (Physics.Raycast(ray, out queryName, 10))
        {
            queryNameText.text = queryName.transform.tag.ToString();

            if (queryNameText.text == "Plant" && Input.GetMouseButton(0))
            {
                queryName.transform.gameObject.GetComponent<DestroyablePlant>().Delete();
            }
        }
    }
}