Crushed wood is stronger than steel
The most expensive wooden floors have the end grain exposed facing upwards and this is then compressed down, much like the top of a good quality butchers block. Those floors are just about indestructible.The heavier such floors are used the stronger they get!The wood in the article is compressed crosswise to the grain (so they get thinner rather than shorter), using the original planks as the raw organic material to produce an engineered product that has relatively little to do with the original wood. 
While this is very impressive the process does not sound cheap (it is time consuming and will produce quite a bit of toxic waste) and the way the article is worded leaves it ambiguous of the strength increase is relative to the original base material or if it is on an absolute scale using the same cross section.The article states the result is 10 times stronger than the original after being compressed to 1/5th of the size, making it effectively thinner, lighter and stronger at the same time.It appears that the increase in density is where the writer missed the fact that reducing the cross section but leaving the amount of material the same does not result in an increase in strength on an absolute scale, it merely means that if you then laminated five of the densified planks back to the original cross section the result would be 11 times stronger.But then you'd lose much of the weight advantage.So I suspect this is either a space or a strength gain, but not both to the extent the article indicates.In the previous century there was a lot of research done on strengthening wood including gamma radiation and all kinds of other treatments, but none of those ever made it to very high levels of industrial adoption.