Glowing embers or visible flames?

[PKBoo]

Which should it be? We put in a used Fisher insert about a month ago, and have been burning logs that were left behind in the woodshed. Who knows how long they've been there - they smell musty and are very "dirty" (not soil dirt, but bark chips, cobwebs, crumbly stuff, and maybe dust), but we've been burning them because it's all we have right now.

We can't see the fire because of the solid doors, but when we open the doors, usually the logs are embers. Is this okay? How should a fire burn?

[The Paw]

It sounds like the wood is burning fast, which will happen if it is really dry and perhaps some dry rot has set in.

In other words, if you open it right away you will see flames, but eventually all fires burn down to embers. Yours are just burning down faster.