Well, actually you do, or at least you can with copper ore.
It is possible to do some smithing in a wood fire, the cherokee indians here in Ga, used to use hickory blocks,
but for real smithing a forced blast is necessary, in other
parts of the world a simple fan, a goat skin or even breath
power does the trick.
Absolutly, and with bronz, the tin requires the higher temps that twyers give. Also, some copper smelting requires higher temps depending on the impurity. As a blacksmith, you would be interested in some of the forge setups they have found in Southeast Asia. Some of the later replacement casting methods were ingenious.