Isolation of RNA from wood

[Eric Sarnighausen]

I am interested in the isolation of functional RNA from the xylem of red
osier dogwood (Cornus sericea L.) twigs. Only the youngest twigs of
which the maximum diameter is 0.3 inches will be used.
I would be extremely interested to obtain information regarding the
following aspects:

 I.) Optimizing the total amount of extractable RNA (cell breakage)
 
     a.) What is the best way to pretreat (cut, rasp) the wood before it 
         is frozen and stored?
     b.) How is the mechanical cell breakage prior to/at the beginning of 
         the extraction process to be accomplished most efficiently?
     c.) Is it possible to isolate functional RNA (in acceptable amounts)
         from material that has been freeze-dried (and is therefore easy 
         to grind)?

 II.) Optimizing the quality of the isolated RNA

        What potential problems regarding the extraction process itself
        have to be taken into account when RNA is extracted from woody
        material?

 Thanks for your help.

                                Eric