NFS: what happens to local space when remote space is imported?

From: Tlhingan (tlhingan1_at_optonline.net)
Date: 12/31/04 

Date: Thu, 30 Dec 2004 21:01:37 -0500

What happens to the space occupied by the local /usr/ports when a
directory of the same name is imported? does the local drive get
"bigger "? Does one recover local disk real-estate by importing
directories that are common?

O.K., once again, for me more than you;
If the directories were already on there, and then I import on top of
them, I'm actually using the nfs server directory - but what happens
to the space that was on my disk which had (have?) those directories?