Insects on Hem-Fir/SPF lumber?
They are springtails.

There's a picture of one looking happy at It Takes Two to Tango… or Does It? The Curious Courtship of Collembola (Springtails).

Insect Identification Key Order Collembola: the springtails and snowfleas has another picture, labelling the little creature as a globular springtail.

The Kids' Inquiry of Diverse Species has this to say about the diet of springtails:


  Although many species are herbivorous, others are carnivorous feeding on other springtails, nematodes and other small arthropods. Those springtails living in leaf litter and soil usually feed on fungi, plant material, feces and algae.


So there is no need to be concerned.