BLACKBERRY WORK TRIP: The O'ahu Invasive Species Committee leads a volunteer trip for advanced hikers to remove invasive Hima-layan blackberry on Mau'umae trail, 8 a.m.-3 p.m. Saturday. Bring at least 2 quarts of water, a hearty lunch, gloves, hat, sunscreen, mosquito repellent, long pants, long-sleeve shirt and sturdy walking shoes. Meet at Church of the Crossroads, 1212 University Ave. RSVP by June 12 to Julia Parish at oisc@hawaii.edu or 286-4616.

POUHALA MARSH RESTORATION: Help the Hawai'i Nature Center remove invasive species and create habitat areas for endangered Hawaiian stilts, 8:30-11:30 a.m. Saturday at the center. Bring work gloves and drinking water, and wear a hat, sunscreen and covered-toe shoes; expect to get dirty and muddy. Contact Pauline Kawamata at volunteer@hawaiinaturecenter.org or 955-0100, ext.18.

FRIENDS OF HALEAKALA: Hike-in service trips to perform park maintenance and/or invasive species removal, June 21-23. Participants must sign up on the Friends of Haleakala Web site at www.fhnp.org. For more information, contact Farley at 808-248-7660 or Matt at 808-876-1673.

INVASIVE GINGER REMOVAL: Hawai'i Volcanoes National Park ranger Jason Zimmer will lead a work project to remove non-native kahili ginger along the Crater Rim Trail, 9 a.m. June 28. Volunteers should meet at the Kilauea Visitor Center.

Submit items for this calendar to dleone@honoluluadvertiser.com.