In a tray or foil pack normally around 225* F but you have to remember that the chips or pellets are right on top of a heat source, so they are going to be a lot hotter than the ambient chamber temp.
If I remember correctly most wood will combust away from a direct heat source right around 300* F meaning if you placed a tray of wood chips or dust on the middle shelf of your oven at 300* it will ignite eventually after the wood temp reaches 300* It might be 325* I can't remember that far back.
I took fire science classes about 30 years ago.
It's kinda hard to explain........LOL