Crown Princess Masako, who is receiving treatment for a stress-induced illness, attended a greenery conservation event in Chiba Prefecture with her husband, Crown Prince Naruhito, on Sunday.

It was her first appearance for an official duty outside the capital since October, when the couple traveled to Kagoshima Prefecture. She last attended the annual ceremony to commend civic groups working to promote greenery in Yokohama seven years ago.

Crown Prince Naruhito, the eldest son of Emperor Akihito and Empress Michiko, addressed the meeting in the city of Kashiwa, Chiba Prefecture, stressing the importance of involvement of a broad range of people in order to conserve greenery and water resources.

The couple also took part in a tree planting ceremony held in a square within the park where the event was staged.

A man from Kanazawa, Ishikawa Prefecture, told the Crown Princess that his city is sponsoring next year's event. The 52-year-old princess told him, "I'm looking forward to it."