Hello Gary,
I don't believe there is any way to automatically export the items in a
tree to a file. I believe that if you want to populate a file
with all of your items you will need to create some function to iterate
over your tree control and extract the data you are concerned with and
write that to the file. Hopefully this helps -- please let us
know if you have any
additional questions (for faster turnaround you might also consider posting to the
CVI board 
)
Have a great day!
Travis M
LabVIEW R&D
National Instruments