It is not what makes cats attractive in a spring time. That small forest is from tin, crystals grown in vacuum - "tin whiskers". Nothing attractive, if to keep in mind that 1mm whisker (grown in 1 hour) can short-circuit two electronic conductors on PCB.
To properly deal with it needs to cover PCB with polyurethane. Not just regular polyurethane, but - you know - with low outgassing in vacuum.
Funny looking, abstract pictures, anyway!