The firm has been awarded the £1.5m forestry and tree maintenance contract with Solihull Metropolitan Borough Council after a competitive tender process.
The firm, a division of Parkwood Holdings, first won the contract in 1990. Executive chairman Tony Hewitt said: "I am delighted we have retained what is, for Glendale, a legacy contract to provide arboricultural services for Solihull.
"We have always had a good working relationship and will work with the council to provide an enhanced service to the community over the next few years."
Locally, Glendale also undertakes grounds maintenance contracts in Birmingham, Warwick and Nuneaton.
Glendale's arboricultural business has continued to thrive through the recession, with new business in the London Borough of Hammersmith and Fulham and Epsom and Ewell in Surrey.
The firm also runs arboricultural contracts from offices in Watford, Exeter, Bristol and south Tyneside.