Silk oak for BN Plecos?

I have a silk oak tree in my yard, and a rather large branch fell.

I am planning to cut off a length of it, bore a 3"diameter hole, 8" deep down the length of it, stopping short of the end of the branch, so there's only one entrance, bleach, boil, boil, boil, and then use it as a BN pleco cave.

Does anybody know if silk oak will be ok for aquarium use? Will it leach anything harmful? Will it be ok for a bn to injest?

Thank you for your help!

It seems the latin name is
[h=1]Grevillea robusta[/h]

Forgot to mention that I'm going to remove the bark. This tree actually drops branches all the time. I drag them to a spot in my yard and let them sit in the sun until I get low on fire wood and then I chop them up. I live in San Diego, so the firewood lasts a while. I think the branch I chose has been sitting there for a couple years.

I'm going ahead and making the pieces, boiling them, and sinking them. I don't want to actually put them in an aquarium until I hear back about safety of this specific type of wood, grevillea robusta, or silk oak, silky oak, or silver oak.

Does anybody have experience with this wood, or knowledge of someplace that I can find information on it's safety for aquariums, and specifically for BN plecos? Or am I being paranoid?