Gameobjects not spawning after i destroy them (Unity)

Im trying to make a first version of a game with unity, but the trees wont keep spawning after i have destroyed the tree amount to less than 5. In unity when i run the game it displays the tree amount and when it reaches 5 it stops spawning them but if i destroy one it wont spawn a new one even tho the tree amount is less than 5.

Also if i keep destroying them so there is always just two trees then it keeps spawning. But whenever it reaches 5 then it stops.

I have two scripts:

This is the one where if i click the tree it destroys it.

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class Harvest : MonoBehaviour
{
    public GameObject tree;
    public int treeScore;
    public void AddTreeScore()
    {
        treeScore++;
    }

    private Spawner spawnerScript;
    void Start()
    {
        spawnerScript = FindObjectOfType<Spawner>();
    }

    public void OnMouseDown()
    {
        GameObject.Destroy(tree);
        spawnerScript.treeAmount--;
        AddTreeScore();
        Debug.Log(treeScore);
        

    }


}

And this is everything else.

using System.Collections;
using System.Collections.Generic;
using Unity.VisualScripting;
using UnityEngine;

public class Spawner : MonoBehaviour
{
    public GameObject tree;

    public int treeAmount;

    public float spawnRate = 1f;

    public bool canSpawn = true;

    public int maxAmount = 5;

    private IEnumerator Spawning()
    {
        WaitForSeconds wait = new WaitForSeconds(spawnRate);

        while (canSpawn == true)
        {
            yield return wait;
            
            Vector2 randomSpawnPos = new Vector2(Random.Range(-10, 11), Random.Range(-4, 5));
            Instantiate(tree, randomSpawnPos, Quaternion.identity);
            AddTreeAmount();

            if (treeAmount >= maxAmount)
            {
                canSpawn = false;
                
            }
            if( treeAmount < maxAmount)
            {
                canSpawn = true;
            }
            

        }
    }
    void AddTreeAmount()
    {
        treeAmount++;
    }

    void Start()
    {
        StartCoroutine(Spawning());
    }

    void Update()
    {
        
    }
}

I also tried setting the spawnRate to 0f; and then back to 1f;, but that did not work. It showed in unity that the spawnRate went to 0 but it kept still spawning them.

I think i have to set the canSpawn back to true some other way. Or is there more errors or mistakes?

>Solution :

Your coroutine Spawning runs exactly once – at the beginning of the game.

void Start()
{
    StartCoroutine(Spawning());
}

Once canSpawn = false; is reached it will never run again.

Instead you could use a field for tracking if an instance of that routine is already running and if not run a new one like e.g.

public class Spawner : MonoBehaviour
{
    // in general for things you only set up via the Inspector
    // you should use private o avoid other classes to modify them (Encapsulation)
    [SerializeField] private GameObject tree;
    [SerializeField] private float spawnRate = 1f;
    [SerializeField] private int maxAmount = 5;

    // backing field for treeAmount
    private int _treeAmount;

    // keeps track whether a Spawning routine is already running
    private bool spawning;

    public int treeAmount
    {
        get => _treeAmount;
        set 
        {
            // this is executed whenever a value is assigned

            _treeAmount = value;
            RunSpawningRoutine();
        }
    }

    private void Start()
    {
         RunSpawningRoutine();
    }

    private void RunSpawningRoutine()
    {
        // if already spawning ignore
        if(spawning) return;

        StartCoroutine(Spawning());
    }

    private IEnumerator Spawning()
    {
        // just in case double safety for blocking concurrent routines
        if(spawning) yield break;

        // block other routines from running (see above)
        spawning = true;

        // simpler and cleaner loop condition
        while (treeAmount < maxAmount)
        {
            yield return new WaitForSeconds(spawnRate);
            
            // generally note that this does not prevent two trees spawning in the same spot
            var randomSpawnPos = new Vector2(Random.Range(-10, 11), Random.Range(-4, 5));
            Instantiate(tree, randomSpawnPos, Quaternion.identity);
            treeAmount++;
        }

        // allow a next routine to start
        spawning = false;
    }
}

This way whenever a value is assigned to treeAmount it will kickoff RunSpawningRoutine. Here you will check whether a routine is already running in which case you don’t have to do anything, but if not it will start a new routine.