Jeff Mikulina, director and spokesman for the Sierra Club's Hawai'i chapter for 10 years, will step down next month.

His last day will be Sept. 27, the day the chapter celebrates its 40th anniversary, the chapter said in a news release.

"We all owe Jeff a debt of gratitude for leading the good fight to protect Hawai'i's environment for present and future generations," said Isaac Moriwake, the chapter's executive committee legal chair. "In a time when we all need to do our part to save our planet, Jeff showed us that one person really can make a difference."

During Mikulina's tenure, the chapter said, membership grew 50 percent to more than 5,500 and the budget nearly doubled.

"Working every day to protect the most beautiful piece of the planet has simply been a dream job," said Mikulina.

For details on the chapter's 40th anniversary gala, go to www.hi.sierraclub.org.