Unity - Convert terrain trees to GameObject's

using System;
using System.Collections.Generic;
using System.Linq;
using UnityEngine;
using Object = UnityEngine.Object;
#if UNITY_EDITOR
using UnityEditor;
#endif

[RequireComponent(typeof(Terrain))]
public class ConvertTreesToGameObject : MonoBehaviour
{
    [SerializeField]
    private Terrain terrain;

    private void Reset()
    {
        terrain = GetComponent<Terrain>();
    }

    [ContextMenu("Extract")]
    public void Extract()
    {
        List<GameObject> children = new List<GameObject>();
        foreach (Transform child in transform)
        {
            //Skip the first, since its the terrain itself
            if(child == transform) continue;

            children.Add(child.gameObject);
        }

        foreach (GameObject child in children)
        {
            //Remove all previously created objects first
            DestroyImmediate(child);
        }

        for (int i = 0; i < terrain.terrainData.treePrototypes.Length; i++)
        {
            TreePrototype tree = terrain.terrainData.treePrototypes[i];

            //Get all instances matching the prefab index
            TreeInstance[] instances = terrain.terrainData.treeInstances.Where(x => x.prototypeIndex == i).ToArray();

            for (int j = 0; j < instances.Length; j++)
            {
                //Un-normalize positions so they're in world-space
                instances[j].position = Vector3.Scale(instances[j].position, terrain.terrainData.size);
                instances[j].position += terrain.GetPosition();

                #if UNITY_EDITOR
                GameObject instance = PrefabUtility.InstantiatePrefab(tree.prefab, this.transform) as GameObject;
                #else
                GameObject instance = Object.Instantiate(tree.prefab.gameObject, this.transform);
                #endif

                instance.name = tree.prefab.name + j;
                instance.transform.position = instances[j].position;
                instance.transform.rotation = Quaternion.Euler(0f, Mathf.Rad2Deg * instances[j].rotation, 0f);
                instance.transform.localScale = new Vector3(instances[j].widthScale, instances[j].heightScale, instances[j].widthScale);
            }
        }
    }
}

#if UNITY_EDITOR
[CustomEditor(typeof(ConvertTreesToGameObject))]
class ConvertTreesToPrefabInspector : Editor
{
    private ConvertTreesToGameObject script;
    private void OnEnable()
    {
        script = (ConvertTreesToGameObject)target;
    }

    public override void OnInspectorGUI()
    {
        base.OnInspectorGUI();

        if (GUILayout.Button("Extract trees"))
        {
            script.Extract();
        }
    }
}
#endif