Glen, I agree with you. I would think the V. Gordon Dillon x Kretcant is probably a very dark blue color.
I have no clue about the Eucalyptus tree. I have seen tons of Eucalyptus trees, and I now try to pull out of my memory if I ever saw any type of other plants attached to them. I don't think so, but then they were usually planted as "replacement/reforestation tree".
If the roots are so imbedded that you have to clip them really close to the plant, I would probably leave it alone. If it involves just clipping the ends of the roots, or some of the roots only, you should be ok. Other than that, I would see if more waterings and plenty of fertilizer help. Vandas do like a lot of water and fertilizer anyway!
It certainly is a very pretty Vanda!
Sorry, I was not much of help here, I hope others will add here. In the meanwhile I will do some more googling on Eucalyptus trees.
edited to add - here is an article about Eucalyptus mulch-
http://homeguides.sfgate.com/e...
My take-away from this is that a fresh/live Eucalyptus might make for a not so happy Vanda, but in your case the wood is old ( ? -- how attached is the dead piece of wood to the healthy tree) and I would think that any offending compound might have evaporated by now or is thoroughly washed out and away.
Another possibility - can the whole piece of wood with the attached Vanda be somewhat severed from the main tree?