I understand about these diseases, as I am a frequent camper and we travel through many states on our trips. I had one guy tell me I couldn't transport mesquite because of that. Mesquite!
As for the BS at the CA border, next time cover the wood or place it in other things. I wouldn't transport forbidden kinds, but when it comes to things which I know are innocuous I consider the game to be on.
When it comes to the CA/US border, the above posters are right - do NOT joke with these guys. I had to bite my tongue a lot. Going into Canada, we were stopped by the very nice young man and questioned for no less than 15 minutes. During our shared time there at the booth, about 25% of the questions consisted of repeatedly asking about guns owned, what type, how many, did you have any with you - over and over again in between other things. I readily listed all the foods - processed and fresh - that we were importing, and he didn't care about them at all (including some I found out later were proscribed). He was very nice, but it got old after a while.
I'm very familiar with that issue in cross-border travel, and have never been tempted to try and cheat it. It would never be worth it. Now, I am certain they don't process every man & wife in that manner, or the line would have been backed up across the bridge into Buffalo. I can only account for it happening because we were in a 4wd F350 Crewcab Diesel with full bumper treatments and Texas plates. I told him I didn't have any horses or oil wells either.
Coming back, the US agent was a complete a$$. We didn't have to unload; didn't even have to show our certified copies of birth certificates or anything. He just had a crappy attitude and seemed to derive pleasure out of holding us up.
Sorry about the rant.