That weird checkerboard texture is the default that is used when the appropriate texture is missing, so you will see it crop up in odd places here and there. These textures and other art-type files are distributed via the updater - as your run is very recent, then there is not much you can do to fix the situation, you already have all current art files. It will be the same way for everybody, regardless of the OS, the art files should be the same on every platform, so like LigH says, its a world-wide problem ( rather than a Linux-specific problem ) at the moment.
That said, that part of the trees was rendering nicely a couple of months ago with a nice leafy texture, it was probably inadvertently deleted or removed for mysterious reasons that only the dev team can fathom.
