Let’s be upfront: Alpha Trees Pro 2.3.3 is a paid add-on, originally sold on Blender Market and Gumroad. While the keyword “free download” is heavily searched, the official developers do not offer a free version.
The add-on does not merely import static images. It provides a parametric interface to modify: Alpha Trees Pro 2.3.3 for Blender Free Download
Version 2.3.3 includes an expanded library of assets: Let’s be upfront: Alpha Trees Pro 2