The Magnuson Park Wetlands need your help removing invasive blackberry shrubs. By no means should this volunteer project be confused with blackberry picking, which is done in the height of summer and rewards you with a pail full of delicious bounty. On the contrary, this activity takes place in the dead of winter and you'll be rewarded with scratched-up arms and soggy boots. However, native plant species will be grateful for your hard work. (Warren G. Magnuson Park Wetlands, 6370 NE 65th St, Building 308, 9 a.m., free)