Today, I have encountered problems trying to read data from sshfs share in apache2. I was getting 403 Forbidden error. It turned out you need to enable other_user in sshfs, so other users than the one mounting the share can access the data, as apache2 is using www-data user.
# uncomment last line of /etc/fuse.conf
# Allow non-root users to specify the allow_other or allow_root mount options.
# enable other_user and read access by non-root
sudo chmod a+r /etc/fuse.conf
sudo umount DESTINATION
sshfs -o allow_other SHARE DESTINATION