What shavings
specifically? From milling, sawing, turning..... or chipping the branches freshly cut from the trees felled?
Ramial wood chippings are the branches from trees trimmed around power lines or other places. The include a lot of bark on which live a multitude of organisms that are usually happily balanced in the natural world, but when you run them thru a chipper, especially with green leaves, and pile them up it can create a petri dish for a toxic overgrowth of molds. This might not
always be the case, may depend on other factors, but the chances are rather high.
I suggest aging fresh chippings due to this story, where fresh chippings put in a run killed a flock of birds and the cause of death was determined by poultry experts who tested the birds and the chippings and found a gross over growth of aspergillus molds:
https://www.backyardchickens.com/threads/dying-chickens.1129854/