1. No, you can unxz then dd the image to your sd card with linux (see below) or mac. On windows you need an unzipper and w32diskImager or similar.
2. If a sd card is in at powerup/reboot, the pinebook will attempt to boot from it.
unxz -c /path/to/pinebook_linux.img.xz | sudo dd of=/dev/sdX
2. If a sd card is in at powerup/reboot, the pinebook will attempt to boot from it.
unxz -c /path/to/pinebook_linux.img.xz | sudo dd of=/dev/sdX