The five plus five years contract, estimated to be worth between £8m-£10m, will see Gristwood and Toms work with Enfield Council to build on its reputation for its high standard of tree maintenance.
Enfield Council senior arboricultural officer Andy Robinson said: "I am delighted to be able to announce that Gristwood and Toms has been successful in being awarded the contract to deliver a range of planned and reactive arboricultural works for the council.
"We have absolute confidence in their ability to deliver our requirements and ensure residents of Enfield continue to receive value for money."
Gristwood and Toms has worked for Enfield Council for over 20 years.
Gristwood and Toms sales head Darren Kilby said: "Our teams have a proven track record delivering tree maintenance services to Enfield Council and to local authorities across the UK. This is one of the largest local authority tree contracts in the country. The award underlines our experience in this sector and consolidates our position as key partner to public sector authorities."