Born in 1959 in Meru County, Mrs. Matumbi has interacted with  the Meru forest ecosystem since an early age. As she joined  her mother to plant trees and grow crops as part of plantation establishment popularly referred to as shamba (farm) system, she became passionate about environmental conservation. After completing high school, Mrs. Matumbi embarked on community mobilization to tackle issues affecting women livelihoods, such as income sources, food and environmental conservation. By 1997 the community had started dairy production using goats and later tree nurseries on farm. As the locals were affected by escalating forest destruction in late 1990s, including illegal logging and poorly managed forest plantations, Mrs. Matumbi joined other like-minded women and spearheaded a movement on forest protection: the Meru Forest Environment Conservation and Protection Association (MEFECAP), which she co-chaired until 2017. She later joined the Meru County Community Forest Association and a national alliance of community forest associations (NACOFA), an umbrella of all CFAs in the country Kenya, where am also a board member, serving also as board member.

Mrs. Matumbi has helped  raise funds for forest conservation and community livelihood support from several organizations, including Farm Africa, European/UP-TANA, UNDP, Government of Kenya. She supports land restoration initiatives and is involved in several community training programs for natural resources management and forest protection.