fusefs-kmod-0.3.0_3 requires the Kernel source to be installed

[Sam Cates]

# cd /usr/ports/sysutils/fusefs-kmod/
# make install clean
===> fusefs-kmod-0.3.0_3 requires the Kernel source to be installed. Set
SRC_BASE if it is not in /usr/src.

I'm new to freebsd and ports.  Is there not a port that will fetch the
Kernel source I need?
If not, could someone please direct me where to find the source?
Thanks