Arboriculture and landscape manager John Parker, who is in charge of 26,000 street trees and 815 sq km of woodland across TfL's estate, told Horticulture Week: "There are always a lot of challenges. For us it's really important that local and national government are putting in policy about trees. It's the best situation policy-wise I've seen in my 10 years in arboriculture."
He acknowledged that things were "quite difficult still without much money" but added "people are passionate about their trees. It's great that they are expressing an interest."
Responding to this week's Budget pledge of £60m of new money for trees, including £10m for street trees, he said: "Any mention of trees from Government is to be welcomed. We need to make sure that as well as having money to plant trees we need to have money to look after them.
There's more and more good policy and positive noises. As always the devil is in the detail and we need to make sure that anything that's done is done with sustainability in the future in mind.
Speaking at IOG Saltex today, Parker welcomed the London Mayor's Transport Strategy and the London Environment Strategy - both of which expressed the intention to retain existing trees and plant more.
In his talk he outlined the main advantages of trees and the responsibilities of managing trees on land you care for. Shade, shelter from rain and flood attenuation were three reasons trees should be seen as an asset, he told delegates.
"Some tropical trees have been shown to catch 60-70% of rain that falls on the tree in the canopy. It slowly trickles down into the earth. This is something we can use in an urban environment to benefit people and save money," he said.
"The major benefit of this that we are trying to promote is health. Children who grow up around trees have been shown to have fewer allergies. Research has shown that in areas with more tree canopy there are lower incidences of antidepressant prescribing. Instead of just throwing pills at people for many health problems get them out among trees and green infrastructure." Other research shows that life expectancy increases when people live in close proximity to trees.
He recommended custodians of green spaces with trees to make friends with their local tree officer. Austerity has affected arboriculture departments but every local authority should have at least one, he said.
It is essential to engage registered arboriculturists to check trees often and have a good recording system, even if it is just a one-page document saying when and how trees are checked in any one year. Be aware of your responsibilities. For example trees growing next to a main road are high-risk, he added. If something goes wrong, claiming ignorance will not help with the authorities.
He urged delegates to keep existing trees and plant more, not see them as a risk and problem to be solved. "It's a fantastic legacy to have planted and looked after trees in your care."
TfL has a commitment to plant 1% more street trees a year between 2016 and 2025 on its road network and borough roads to protect tree canopy cover.
Parker has given a TEDx talk - Why trees are better than people - which can be seen on YouTube.