This kiln dried firewood consists of a mix of sizes of logs. Unlike the boxes, the bags only include logs. 
 
Why do we use Certainly Wood?
Flaming firewood are kiln dried logs, being force dried in kilns rather than drying naturally or being "seasoned" over a period of time. The wood is dried to below 20% moisture content, making it ready to burn on all appliances. 
Certainly Wood selects its logs from sustainably managed, British woodland. In other words, the trees used are removed to ensure the ongoing health of the forest or woodland.
The kiln drying process also substantially reduces the smoke, debris and tar produced by logs when alight.