Hi John,
The first tree you photographed is Acer tataricum var ginnala. A selected cultivar is available in the nursery trade from time to time, called 'Hot Wings', that has really bright red samaras. There is a similar tree here in Bear River, behind "Flight of Fancy" Gallery.
I am guessing that your Alnus is Manchurian/Siberian alder (Alnus hirsuta), but I may be wrong.