Birch Shrubs (publ. 2023-08-30)

I'm still struggling with the identification of some shrubs. Here are photos of one, from last Thursday (Aug 24) near the Tanana River:

shrub exhibit A

shrub exhibit B

shrub exhibit B

I believe this is the same thing as what I had identified earlier as Resin Birch (Betula glandulosa) but am doubting this identification now. Looking again at the sketches in my book ("Alaska Trees and Shrubs", 2nd ed., Viereck et al, pg. 150.), the leaves do not look the same. I'm thinking it must be some kind of birch, though.

The double-toothed featured of the leaves looks similar to the sketches of Western Paper Birch (Betula papyrifera), but that does not grow in the interior, and is not a shrub. The leaf is similar to the sketches of Sitka Alder (Alnus sinuata) which is a shrub, but it is not supposed to be growing in Fairbanks, and also the twig description doesn't match. As to the twigs, there appears to be some similarity with Siberia Alder ("Hairless, smooth, dark brownish-red, with many light dots") but the leaves are very different.

The book mentioned that there are hybrid birches (Betula hybrids). Yukon bark is mentioned, having a Reddish-black bark, with twigs "densely covered with glandular dots" but the leaves are supposed to have rounded teeth.

So, I'm not sure what to make of these shrubs.