developed by IDV (Interactive Data Visualization). There is no legitimate "free library download" of the full SpeedTree software or its complete asset library. Downloading cracked or pirated versions would violate copyright laws and the software's terms of service.
: An interesting use case of SpeedTree (specifically SpeedTreeRT) for visualizing realistic-looking trees in real-time within GIS (Geographic Information Systems) is discussed in research featured on ResearchGate Industry Standard Overview speedtree library free download
You can download official and community-made SpeedTree assets from several reputable platforms: Official SpeedTree Store Freebies SpeedTree Store developed by IDV (Interactive Data Visualization)
SpeedTree | The Industry Standard for Procedural Modeling - Unity SpeedTree | The Industry Standard for Procedural Modeling. July Bonus Content - SpeedTree speedtree library free download