Acacia sieberiana var Woodii
I know these photos are not ideal for the point I'm trying to illustrate but they'll do. The first picture was taken in 2002 about 4 months after I'd planted the paperbark thorn.
In the next photograph my sister is standing next to it for comparison 4 years later. The funny thing is that although we water it like theres no tomorrow the position its planted in is pretty much solid slate, we had to chop a hole with a pick axe to plant it there which was back breaking work.