One thing that I can tell you about the TD trees is that they have a more realistic variety of tree sizes for a given species. Up close, they still don't look anywhere near as good as the 3D speedtrees, but once aloft, 2.5D billboard trees are still billboard trees, so the differences among the three packages have more to do with seasonal color changes.

16 hours ago, flyblueskies said:

Here's a better in depth explanation from Orbx:

"Neither Trees HD nor TerraFlora place any trees themselves they just replace the textures and models of the default autogen trees. Trees HD does it by swapping out the default tree library and textures while TerraFlora deactivates the default library and activates the replacement library and textures in a separate scenery folder. In short, the method is different but the result to the user is the same.

Some Orbx global and regional products also place tree models from custom libraries of our own, given that the default set is quite limited in terms of tree types/species. If Trees HD isn't installed then those additional trees will use their original Orbx standard-resolution textures; with Trees HD installed they display HD textures. 

 

Thus, as mentioned above, with both TerraFlora and TreesHD installed all default trees will use TerraFlora models & textures while custom Orbx models, often mixed with the default models, will show Orbx HD textures." 

 

Thank you a lot for pounting out this very useful explanation in a nutshell 😀. 

Now I can understand the purpose of the FTXTreesHD Folder in ORBX/Scripts; very enlightening.