MTLLoader problem - object is black coloured

Question

I'm having trouble loading textures. I've tried several ways but my object is still black. What am I doing wrong?

const onProgress = function (xhr) {
  if (xhr.lengthComputable) {
    const percentComplete = (xhr.loaded / xhr.total) * 100;
    console.log(Math.round(percentComplete, 2) + "% downloaded");
  }
};

**const mtlLoader = new MTLLoader();
mtlLoader.setPath("./models/low-poly-tree-concept/source/tree_2/");
mtlLoader.load("tree_2.mtl", function (materials) {
  materials.preload();
  const objLoader = new OBJLoader();
  objLoader.setMaterials(materials);
  objLoader.setPath("./models/low-poly-tree-concept/source/tree_2/");
  objLoader.load(
    "tree_2.obj",
    function (object) {
      scene.add(object);
      object.scale.setScalar(0.005);
      object.position.set(-2, 0, 1);
    },
    onProgress
  );
});**

How to apply the texture?