The company, which won a Highly Commended award at the 2018 Horticulture Week Business Awards, said demand has grown for its expert advice.
Chairman John Lockhart said "Requirement for the services and expert advice that we provide around trees, ecology, woodland, forestry, landscape planning and design and green infrastructure has grown as people increasingly recognise the commercial and environmental importance of forests, trees and woodland."
Set up by John Lockhart in 1998, the company now employs almost 40 staff at offices in Chipping Norton and Corby and works in a range of associated disciplines including arboriculture, ecology, landscape architecture, forestry, woodland management, soil survey and land restoration.
The practice has just produced a free guide on dealing with ash dieback to help anyone with responsibility for managing and maintaining locations where ash trees grow.
Warning that "there is limited time for action" the environmental planning and forestry consultancy hopes that Sunset for Ash Trees, will help people develop a balanced approach to the Chalara ash dieback which arrived from Europe in 2012.
It has developed a specific process for managing ash trees in its RACER programme (Resource, Approach, Compliance, Execution and Replant). This system identifies the importance of understanding tree stock and determining the objectives for that stock, as well as good management, coordinating operations with legislation, undertaking arboricultural and/or forestry works and planning replacement planting.