Pierre was president of the Quebec Society of Landscape Architects (1989-1991) and president of the International Symposium on the Conservation of Parks and Urban Squares (1993). He was board member of the Pole des Rapides Tourism Corporation and of the Quebec Environmental Law Center. He is vice-president of le Réseau de milieu naturels protégés du Québec. In 2014, Pierre was introduced to the “Doers” group of Société Provancher d’histoire naturelle du Canada.
Pierre is a founding member of les Amis de la Montagne since 1986, an NGO dedicated to the protection of mount Royal. He is member of the Advisory Committee of “Give Green Canada/ Patrimoine vert” set up to increase green philanthropy in Quebec and Canada and member of the organizing Committee of Ateliers sur la conservation des milieu naturels which provide training to conservation NGOs in Quebec. Between 1994 and 2001, he acted as advisor for acquisition of natural space in the Montreal area.
He set up the Private Stewardship Program of Parc de la Rivière-des-Mille-Îles in 1994. He was project landscape architect for Parks Canada, Atlantic Region were he designed and realized projects for Kouchibouguac and Fundy National parks (1983-1986).