Textures and stylizing

And lots of brushes... Check out Kyle's Brushes - https://www.kylebrush.com/. Use a Wacom tablet...

I initially thought it might be a 3D rendering, but I now think it is a digital drawing.  The nearly horizontal lines across the trunk have a hint of depth.  As long as the lines are on their own layer, you can use Bevel & Emboss to create the effect of depth.  Setting Direction to Down works best, but it depends on the Direction settings.

If you add some white to a new layer and blur it, we give it some depth.  We extend the depth effect with some inner shadow layer style.  Splatter brushes are an easy way to add that texture, but it is not hard to make splatter brushes by setting size and scatter jitter in the preset panel.

So draw and fill the outline.  Keep using new layers as you build it up add eyes ears tusks etc.  add shading and highlights always using new layers so you can move and blur.  It's actually a really easy digital painting to do and wouldn't take long.  I used all those techniques and more to make this digital painting of my wife.  Check out some of Bert Monroy's tutorials on digital art to see how it is done.

Good luck.  This is a rewarding way to use Photoshop, and a lot of fun.