Interesting. Keep in mind that the sound also depends on other factors, such as body shape and size, saddle material, sound hole size and placement, strings, cut of the wood, finish and even how it's held, so while the video is very informative, it is only a general guide and applies more to that line of ukes than to ukes in general. Two of their koa ukes may sound different simply because the wood cut is from different parts of the tree and has different grain patterns. I think the caveat at the end is very important.
Plus there's a whole question about the fidelity of the recording... placement and style of mic, etc. that affect the result.
Personally I can't hear a huge difference is sounds or tone until the fir top, which to my ears has a marginally brighter sound. But nonetheless, I appreciate the comparison and will link to it on my own site as useful for people trying to decide what woods to look for.