public float getHeightmapHeight(float x, float z) {
        if (x < 0 || z < 0 || x >= size || z >= size)
            return 0;
        int idx = (int) (z * size + x);
        return getMesh().getFloatBuffer(Type.Position).get(idx*3+1); // 3 floats per entry (x,y,z), the +1 is to get the Y
    }
The maximum lod supported by this terrain patch.
If the patch size is 32 then the returned value would be log2(32)-2 = 3
You can then use that value, 3, to see how many times you can divide 32 by 2
before the terrain gets too un-detailed (can't stitch it any further).
@return the maximum LOD
jme3-terrain/src/main/java/com/jme3/terrain/geomipmap/TerrainPatch.java