I've seen a lot of videos with people inoculating the length of the logs. Why don't people do the width?
With the exception of "trees" such as palm trees, as a tree grows the inner conductive tissues lose their ability to transport nutrients up or down and become hardened into heartwood, providing structural strength and leaving the outer tissues to keep the roots and canopy supplied with food. So the "length" under the bark is soft wood and will be more easily penetrated by the fungal mycelium and providing a quick establishment of the colony. While you can inoculate the ends it will only work satisfactorily when the wood is very soft such as with North American basswood where the heartwood remains spongy or palms which do not produce heartwood since they are grasses, designed to bend in high wind rather than attempt to stand straight and stiff.