Caring For Your Logs
Generally speaking, the fresher the log the better. Some species, such as Alder, can be especially prone to decay or stain if seasoned too long prior to milling and drying. However, there is always an exception to the rule, as aging can sometimes impart spectacular coloring and spalting (spalted Maple, blued pine, orange flamed Alder).
To note, as logs season and dry, they can begin to form checks and splits at the end of the log. To reduce this potential, one can either leave extra trim allowance (6-12 inches) or apply an end coat sealant as soon as possible after the tree is felled to reduce this potential. The harder the species of wood, the more important this can be.
Fundamentally, wood dries ~10x faster through the end grain than radially through the sides. Applying end coat slows the moisture loss from the end of the wood, thereby allowing more even drying and less frequency of checks and splits.
For more information on taking care of your logs, check out Chapter 14 of the Wood Handbook.