Yes, exact same problem (SpeedTree 8 models). The textures are not mapped correctly on almost all of my models in the "Temperate Deciduous Forest Pack" I purchased. They are stretched on certain sections of the trunk and branches for multiple models. If I change all the texture import settings to "repeat" instead of "clamped" it helps a bit, but still pretty much unusable in a real game. This is a glaring mistake/issue! I hope someone from SpeedTree sees this and can fix it.