void Start()
    {
        gridManager = GameObject.FindObjectOfType<GridManager>();
        worldPlacer = GameObject.FindObjectOfType<WorldPlacer>();
        itemMenu = GameObject.FindObjectsOfType<ItemMenu>();
        moneyManager = GameObject.FindObjectOfType<MoneyManager>();

        importMenu = GameObject.FindObjectOfType<ImportMenu>();
    }
        private void enableTrees()
        {
            var placer = new WorldPlacer
                         (
                getItems: () => TW.Data.Objects.OfType <Tree>(),
                getPosition: tree => ((Tree)tree).Position,
                setPosition: (tree, position) => ((Tree)tree).Position = position,
                getBoundingBox: tree => ((Tree)tree).Physical.GetBoundingBox(),
                createItem: () => new Tree(),
                deleteItem: t => TW.Data.RemoveObject((Tree)t)
                         );

            controller.Placer = placer;
        }