Generating a Mesh instead of a bunch of gameobject

I created a tree generator for my game. It uses unity cubes and pre-made leaves and assembles them to create a mesh. The problem? The tree is only 4.7k tris but it lowers the fps (from 113 fps to 78 fps). If was wondering if I could create the exact same tree but all in one mesh. The problem: I cannot scale/rotation a bunch of triangles to create this exact same tree:

The code:

         case TreeCreatorTools.TreeShape.Round:
             TreeHeight = Random.Range(LogMinHeight,LogMaxHeight);
             TreeSize = Random.Range(LogMinSize,LogMaxSize);
             DistanceBettwenBranch = Random.Range(MinDistanceBettwenBranch,MaxDistanceBettwenBranch);
             CurrentHeight = 0;
             CurrentScale = 1f;
             beforeRadius = 0;
 
             float BranchDistance = DistanceBettwenBranch;
             float BranchDirection = Random.Range(0f,360f);
 
             //GameObject Obj;
 
             for(int tH = 0; tH < TreeHeight; tH++) { //Tree Height
                 Obj = (GameObject)Instantiate(ObjectTemplate,transform);
                 Obj.transform.localPosition = new Vector3(0f,CurrentHeight,0f);
                 CurrentScale = TreeSize * (logCurve.Evaluate((float)tH/TreeHeight)*logCurveInfluence);
                 Obj.transform.localScale = new Vector3(CurrentScale,CurrentScale,CurrentScale);
                 Obj.transform.GetChild(0).GetComponent<MeshRenderer>().material = LogMaterial;
 
                 if((float)tH/TreeHeight > HeightBeforeBranch) {
                     if(BranchDistance >= DistanceBettwenBranch) {
                         //Setup a branch
                         Obj = (GameObject)Instantiate(ObjectTemplate,transform);
                         Obj.transform.localPosition = new Vector3(0f,CurrentHeight,0f);
                         float THICCness = Random.Range(0.14987f,0.3756f);
                         Obj.transform.localScale = new Vector3(THICCness,RoundFoliage.Evaluate(((float)tH-beforeRadius)*(1f/(TreeHeight-beforeRadius)))*7.8f+Random.Range(MinBranchLenght*0.075f,MaxBranchLenght*0.075f),THICCness);
                         Obj.transform.eulerAngles = new Vector3(0f,BranchDirection,BranchRotation-100);
                         Obj.transform.GetChild(0).GetComponent<MeshRenderer>().material = LogMaterial;
 
                         Mesh UVEditor = Obj.GetComponentInChildren<MeshFilter>().mesh;
                         List<Vector2> UVs = new List<Vector2>();
 
                         for(int i = 0; i < UVEditor.uv.Length; i++) {
                             if(i < 4) {
                                 UVs.Add(new Vector2(UVEditor.uv[i].x*Obj.transform.localScale.z,UVEditor.uv[i].y*Obj.transform.localScale.y));
                             } else if(i < 6) { //8 -> 12 
                                 UVs.Add(new Vector2(UVEditor.uv[i].x*Obj.transform.localScale.x,UVEditor.uv[i].y*Obj.transform.localScale.z));
                             } else if(i < 8) {
                                 UVs.Add(new Vector2(UVEditor.uv[i].x*Obj.transform.localScale.z,UVEditor.uv[i].y*Obj.transform.localScale.y));
                             } else if(i < 10) {
                                 UVs.Add(new Vector2(UVEditor.uv[i].x*Obj.transform.localScale.x,UVEditor.uv[i].y*Obj.transform.localScale.z));
                             } else if(i < 12) {
                                 UVs.Add(new Vector2(UVEditor.uv[i].x*Obj.transform.localScale.z,UVEditor.uv[i].y*Obj.transform.localScale.y));
                             } else if(i < 16) {
                                 UVs.Add(new Vector2(UVEditor.uv[i].x*Obj.transform.localScale.x,UVEditor.uv[i].y*Obj.transform.localScale.z));
                             } else if(i < 20) {
                                 UVs.Add(new Vector2(UVEditor.uv[i].x*Obj.transform.localScale.z,UVEditor.uv[i].y*Obj.transform.localScale.y));
                             } else if(i < 24) {
                                 UVs.Add(new Vector2(UVEditor.uv[i].x*Obj.transform.localScale.z,UVEditor.uv[i].y*Obj.transform.localScale.y));
                             }
                         }
                         Obj.GetComponentInChildren<MeshFilter>().mesh.uv = UVs.ToArray();
 
                         //Add the FLUFF at the end of the branch! (Also don't forget to do the prepared branch mode too)
 
                         if(Obj.transform.localScale.y < 1.2f) {
                             continue;
                         }
 
                         int FluffQ = Mathf.RoundToInt(Random.Range(RoundFluffMinSize*0.6f,RoundFluffMaxSize*0.6f));
                         GameObject Fluff;
 
                         for(int i = 0; i < FluffQ; i++) {
                             Fluff = (GameObject)Instantiate(FluffyTemplate,Obj.transform.GetChild(0));
                             Fluff.transform.localEulerAngles = Vector3.zero;
                             Fluff.transform.localPosition = new Vector3(0f,Random.Range(0.1f,0.5f),0f);
                             Fluff.transform.position += new Vector3(Random.Range(-RoundFluffMinSize,RoundFluffMinSize)*1f, 0f, Random.Range(RoundFluffMinSize,-RoundFluffMinSize)*1f);
                             float Size = Random.Range(8f,11f);
                             TreeCreatorTools.SetGlobalScale(Fluff.transform,new Vector3(Size,Size,Size));
                             Fluff.transform.GetChild(0).eulerAngles += new Vector3(Random.Range(-7f,7f),Random.Range(-7f,7f),Random.Range(-7f,7f));
                             Fluff.transform.GetChild(1).eulerAngles += new Vector3(Random.Range(-7f,7f),Random.Range(-7f,7f),Random.Range(-7f,7f));
                             Fluff.transform.GetChild(2).eulerAngles += new Vector3(Random.Range(-7f,7f),Random.Range(-7f,7f),Random.Range(-7f,7f));
 
                             Fluff.transform.GetChild(0).GetChild(0).GetComponent<MeshRenderer>().material = FluffLeavesMaterials;
                             Fluff.transform.GetChild(0).GetChild(1).GetComponent<MeshRenderer>().material = FluffLeavesMaterials;
                             Fluff.transform.GetChild(1).GetChild(0).GetComponent<MeshRenderer>().material = FluffLeavesMaterials;
                             Fluff.transform.GetChild(1).GetChild(1).GetComponent<MeshRenderer>().material = FluffLeavesMaterials;
                             Fluff.transform.GetChild(2).GetChild(0).GetComponent<MeshRenderer>().material = FluffLeavesMaterials;
                             Fluff.transform.GetChild(2).GetChild(1).GetComponent<MeshRenderer>().material = FluffLeavesMaterials;
                         }
 
                         BranchDistance = 0f;
                         BranchDirection += 150+Random.Range(-16.4f,16.4f);
                     } else {
                         BranchDistance += CurrentScale;
                     }
                 } else {
                     beforeRadius++;
                 }
 
                 CurrentHeight += CurrentScale;
             }
             break;