i-Tree Report Is Published

Day One – Kenton Rogers from Treeconomics shows us how it is done.

It’s been nearly three summers since we first ventured out, our pockets bulging with books about trees, the scent of sap and science in our nostrils, and tape measures, maps, rainproof clipboards, and funny bits of plastic with a wobbly circle-thing on them all festooned about our persons – to begin the University of Leeds Campus i-Tree Eco Full Survey.

Learning i-Tree with Kenton and Keith Sacre from Treeconomics (right). (UBoC PhD student Jamie Wilson is on the left, and the three in the middle are Tom Bliss, Anna Gugan and Dr Hannah Walker.

This was the first leg of a long journey which also includes an i-Tree Eco Sample Survey of Leeds’ Middleton Ward (where our Forest Observatory keeps a weather eye on the ancient woodland in Middleton Park), and an i-Tree Canopy survey of the whole city, ward by ward. (Reports on both these, along with other valuation work using CAVAT etc, are in preparation). And there’s more to come, as we work towards better ways to value Natural Capital, and so help to protect existing trees and facilitate the growth of more – while the world gradually remembers how vital the Greenery Machinery is to our heath, welfare – and even survival.

Tim Knighton measuring the last tree in October last year (we’ve done a lot of QA samples since)

The Campus Report has involved many months of detailed work by our i-Tree team. Lead authors are Anna Gugan, Dr Cat Scott, Dr Hannah Walker and Hazel Mooney (with input from Hannah Birch, Tom Bliss, Abyed Chowdhury, Poppy Cooney, Suzanne Robinson, and Dr Kieron Doick). We’ve had sterling help from an army of volunteer surveyors (especially our Champion Surveyor Tim Knighton, above), and huge support from our client partners; Leeds City Council, University of Leeds Sustainability Service, The Woodland Trust, Treeconomics and Forest Research.

It’s vital to get the species right – this one looks like a fern-leaf beech. (The campus is really an Arboretum, with many special and rare trees).

You can read more about the background on our research partner LEAF’s website: https://leaf.leeds.ac.uk/i-tree-leeds-putting-a-value-on-the-citys-trees/

Measuring height with a clinometer.

Here are the key findings:

We found that the biggest trees on campus are having huge benefits: the largest 100 trees, which make up only 7% of the total number, provide over one third of the total environmental benefits in terms of carbon sequestration, pollution removal and flood risk reduction. When a mature tree is removed, the loss will be compensated by planting three new saplings on campus. We found that it can take around 25 years for those three trees to be generating equivalent benefits to the mature tree they replaced.

And the key recommendations are:

• plant long-lived, large canopy, tree species in locations where soil volume is sufficient for them to grow to their full size

• increase campus canopy cover from 17% to a minimum of 20%


• plan for the potential loss of 8% of the campus trees due to Ash dieback


• protect the existing mature tree stock by a continuation and adoption of good practice measures in tree care and management

Rather than duplicating the rest of findings, which you can read on the LEAF page, here are some more pictures and a video clip about the project, made by the Woodland Trust for their Street Trees Awards in 2018.

It turns out the UoL even has a secret garden!
Fraxinus Raywood leaf
And this is a very rare one: Hannah measures a Nothofagus Antarcticus – which once grew in a far-distant place where she was shortly to be working!