Trees and Design Action Group, formed last year, is targeting designers, planners and developers with a set of new guidelines dealing with trees in developments and the value of trees.
Sue James, an architect consultant for Capita Lovejoy, said the first two guidelines would be "unveiled as green papers" at the House of Commons next month.
"We want to challenge then help change policy and tie it into local development decisions," she said of the broad-church group.
It includes Cabe Space, the Forestry Commission and the Landscape Institute as well as councils, researchers, insurance firms, developers and utility companies.
"If we act collectively we have more chance of changing policy because everyone is on a level playing field. This has not been the case before.
"In the past developers, for example, felt they were being held responsible and penalised financially for a lack of trees and greenery."
Two nurseries, Barcham and Willerby Landscapes, also belong to the group.
"The key concept is inclusivity and coming to agreement to avoid a sieve-like effect where one or two influential people or groups fall through."