When they arrived at the Rockridge-Temescal Greenbelt, aka FROG Park, on Saturday morning, Alya Davidman and her 6-year-old daughters Evelyn and Josephine Ellis-Davidman found a group of over 100 volunteers hard at work raking leaves, pulling weeds, and picking up trash across the narrow greenway tucked between a row of houses, the DMV and the Temescal farmers market in north Oakland  Josephine and Evelyn, waddling with bright orange trash pickers in one hand and garbage bags as big as their…