A campfire is made from sticks and logs why do the sticks ignite before

its because sticks have more surface area expose to oxygen

Because of the smaller size, and larger and faster heat absorption capacity

Explanation:

The sticks are more igneous in comparison to the logs because of their smaller size and high heat absorption capacity.

Smaller objects catch fire more readily than the larger ones as it has the ability to absorb more amount of heat energy at a much faster rate compared to the bigger logs.

In addition to this, the surface area also is equally important because larger the area of the surface fuel, the more amount of oxygen molecules can interact with the surface, as a result of which their rapid interaction with the fuel per second enhances the combustion reaction. This is why they ignite more rapidly. The dry objects are burned more rapidly than a wet or a partially wet object.