CRACK or CHECK?

On inspection of the work completed last week, we were concerned about the increased number of 'CHECKS' appearing in many of the main truss arms, the vertical supports and solid logs.
('checking' - crack-like structures that follow the wood-grain direction - nothing to do with bank accounts).

In some places the 'checks' appeared to run the complete length of the wood section. We suddenly had a few questions that needed answering:
Are these cause concern, would the structural integrity of the supporting structure be compromised in anyway?
Are these really 'checks' or 'cracks' in the wood - how could we tell the difference?

Fred phoned the main designer at the log home company. He told Fred that these were not a cause for concern and that they occur when the wood dries out.

We decided to do some of our own investigation and trawled through a huge pile of log home magazines (collecting in the corner of our tiny apartment along side the wood samples, test stain-pots and other Green Log Home product samples).
Firstly, when you look at any pictures of log homes, (inside and out), you will see an abundance of 'checks'.
Checks do look like cracks in the wood, checks tend to follow and run along side the grain direction, whereas cracks, well... they just don't follow the grain at all and tend to be much straighter in appearance.

Reading a little more, we discovered why 'checking' happens:
Explanation of wood types taken from our website section >>Green Advice>>Log Home: Sapwood is located in the outer ring of a tree, near the bark and is the 'living wood'. Consequently it contains a lot of moisture and inevitably shrinks when dried. All wood in a tree is formed in the sapwood. The heartwood is located in the center of the tree. Tension occurs between the cells of the heartwood and sapwood as they dry-out at different rates, as a result the bonds between the different cells break, causing a check to appear! Our home is now dry on the inside, getting drier by the day... as the wood continues to dry we may be surprised to hear the odd 'snap, crackle and POP' noise!