Speaking of boring, there are some intriguing insect larvae boring round-n-round in galls on the alder's branches. These larvae cause lumpy galls to form on the alders. I see several galls on the alder bush pictured above.
I peeled the bark off an alder gall as if I was peeling the skin off of a potato. This revealed the frass-filled galleries of a wood-boring larva that had caused the gall.
This next photo shows an alder gall - an irregular swelling on the upper branches of the alder bush. This is an alder stem gall caused by the larva of an Alder Gall Buprestid - Eupristocerus cogitans.
Alder Gall Buprestid larvae are flat-headed borers. That name comes from the broad thorax.
Here is a photo of another gall that I split open.
I made Alder flitches to display buprestid larvae tunnels.
We've "scratched the surface" with alder galls, don't you think?
See part one in this series on interesting facts about alder.