It appears to be a planting so willows used might not be native to vicinity or even region. Revegetation plantings here often contain species from the intermountain region or even Europe.
I'd be surprised if MetroVancouver Parks paid to import willows when willows cuttings are so easy and willow are so abundant locally. Perhaps a park ranger or the East Area office would be able to help you if you called them. You'd likely need a really good description of the location and the planting area.
Would be made up of kinds already on the market here, and not imported specifically for the Parks project(s). I have seen multiple examples of such plantings containing exotic species such as French pink pussy willow and blue Arctic willow here, as well as shrubs native to western North America but not this part of it being used. Then there is the recurring inclusion of Ribes rubrum, red currant - doubtless a mistake for R. sanguineum, red flowering currant. I have even seen this done in a National Forest.
