Black cottonwood
Populus ( i suspect it is P. trichocarpus)
'mother tree'
A wonderful tree to have a round, called mother tree because apearantly every part can be used
for medice. I myself have P. balsemferia in the yard, it's brother, and i use the spring buds, who have a wonderful fragrance.
This tree is photographed on a spot, from where it probaly has to go, but i am sure if you have one poplar on your lot, there are more, and i find it's brother in my yard propengates by it's roots even faster then it's cousin the Aspen.