Why did these Douglas firs break all of a sudden?

[Benny Nganabbarru]

Raminshooter, when one of those really hard termite mounds is hit (and you can't tell the difference before you shoot it), it is like hitting a concrete wall. The termite mound is almost unmarked - perhaps a slight scrape - and the arrow stops dead and bounces back.

[Looper]

They might do that if they are hitting the hard ground and glancing off it. I've broken a few that way. That also happens occasionally, when I miss a target and it goes bouncing off trees.

[snag]

Any wood shaft, for that matter carbon or aluminum, will find there breaking point when pushed to the limit. We're not shooting rebar...