Mayhew originally began his working life as a journalist before becoming involved with horticulture and arboriculture.
He began by discussing urban tree planting. He said there were two main issues facing urban planners when designing green spaces - money and health and safety.
He added that he did not believe there were enough trained and qualified arborists designing urban areas. This was why it was common to see linear and avenue designed plantings of trees that were "narrow-minded" and "boring".
Mayhew spoke about how new trees were chosen for specific places, emphasising how trees can pull a landscape and its architecture and plants together.
He talked about plant hunters, adding that the UK had just 33 native woody specimens - everything else had been brought into the country over the past 1,000 years. Introducing trees into a landscape must be done with care and thought, he said, because they can help to preserve a landscape.
This is the first dispatch from Peter Seabrook Scholar Award winner at Writtle College Joseph Iacobucci, who is attending the James Hearsham series of lectures at Writtle and reporting on each.
- Meanwhile, Writtle College representatives have met with local residents to discuss plans to sell off 2ha of the college's estate to a developer for housing. The college plans to use the money raised from the sale of the land for investment in college infrastructure and student facilities, in line with its 10-year estate strategy.
Commenting on the proposals, a Writtle College representative said: "The college is seeking to gain consent for possible residential development on land that totals just under five acres, representing around one per cent of its 220ha estate, and is making every effort to communicate widely and consult with the local community.
"The college values its relationship with those residing in Writtle village and the surrounding area very highly and has been encouraged by the support voiced by members of the local community during the consultation process."