Myotis
Could you ask your friend exactly which species she is worried about?
Your link http:// http://www.ukbap.org.uk/UKPlans.aspx?ID=341, is all about species that need mature or ancient wood or hollows. In my job we consider wood, oak for instance, of 10 cm or thicker to be of insect value. Of course it is different for example hazel but I don´t know of any insectspecies that use twigs and are threatened by habitat loss.
But as many posts have shown, it can be a lot about how you wiew things.
Fireing a hobo may not cause species extinction but it will have an impact on something.
If minimising that impact gives you peace of mind then all the better!
I like the quote, but on the other point her remarks weren't specific, it was the principle of not doing things that could potentially make things worse for a group of species now considered to under considerable threat.
I suspect there is a big difference between the role of standng wood and the general availability of wood (sticks or otherwise) on the forest floor for insects and other decomposers to break down. Certainly the link suggests that hollow standing trees/stumps are the most important and its difficult to see how burning a few twigs is likely to have any effect on those particular species.
I'll see if I can find out anything useful.
Graham