We use the protocol described in Kolosova et al., 2004 Biotechniques 36, 821-824 as a standard protocol to isolate RNA from conifer tissues (including bark, xylem and needles). As for DNA extraction, I usually yield good DNA amounts and quality with standard extraction kit from e.g. Qiagen.
Since open access is precluded by the journal, I can't provide you with a copy, but I attached our lab protocol for RNA isolation, which might be even more useful.