Dongria Kondh, also known as Penny Eastwood, is understood to have died peacefully on Monday.
She spent 30 years fighting the effects of climate change and was a founding member of Treesponsibility - the not-for-profit community group which has planted over 250,000 trees since its formation in 1998.
She also founded The Source Partnership and worked with The Environment Agency, Calderdale Council and Yorkshire Water as well as charitable organisations including Slow The Flow and other local groups to promote and utilise natural flood management techniques.
Earlier this year, a new annual bursary was launched in her honour, funded by Calderdale Council, the Environment Agency, National Trust and Slow The Flow, to support masters students investigating natural flood management.
Hebden Royd Town Council said: "It is with great sadness that we have learned of the passing of Dongria Kohdh, otherwise known as Penny Eastwood. She will be sorely missed in the Hebden Royd community and beyond."
Hebden Royd Town Councillor Nikki Harvey said: “A truly inspirational woman who has left such a legacy.
"I believe our hedgerow at High Hirst may have been the last project she was so personally involved with and I remember her insisting she wanted to visit the site and climbing over the gate to access it at the end of last year!
"We learnt so much from her knowledge and vision.”
Calderdale Councillor Josh Fenton-Glynn said: "Dongria made change happen. From treesponsibility to natural flood management. She worked with others and brought people together.
"She was a force of nature. I remember in the lead up to the Iraq war with rising islamophobia, joining her at a Mosque in Halifax to plant a tree for peace. Peace between communities and between nations.
"The world needs more people like her. Thoughts and love to those who knew her best. She left a mark on the world that will be seen by future generations."