In spite of its leafy and green reputation, Sheffield has been receiving bad press recently with regards to how its street trees are being managed and, more troublingly, to how its citizens’ rights to protest are being subjugated.
In 2007, City Council adopted a methodology document, “Streets Ahead”, which categorises trees into one of 6 “D” categories: dead, dying, dangerous, diseased, damaging, and discriminatory.
Apparently the potential for urban vegetation to produce ozone in combination with anthropogenic emissions “has long been recognized, [but] the municipalities actively enlarging their green spaces still generally either overlook or ignore this fact” (Churkina et al., 2015).
This latter comment leads neatly to an Ugly story pertaining to urban trees in the U. The Ugly With more than 250 parks, woodlands, and gardens, Sheffield is Britain’s most treed and wooded city (10.4 percent woodland by area).
While I hoped that people would enjoy our walks, the feedback we received was tremendous.
(One of my highlights: “I’ve always wanted to know how to identify a Hornbeam: thank you!Trees are symbols of health, vitality, and goodness.For the greater landscape and environment, trees and woodlands connect the lithosphere and the atmosphere through their role in the water cycle, whether by absorbing liquid water and facilitating infiltration into the soil and aquifers, or evaporating and transpiring water vapour, along with oxygen and other molecules, into the atmosphere. As in the case of any complex issue, however, there is no such thing as a silver bullet, and the same applies here.With this essay, I’d like to explore some good, some bad, and some ugly stories pertaining to urban trees and forests in Sheffield, England, where I’ve been living for seven years.The Good This year marks 800 years since King Henry III signed the 1217 Charter of the Forest, which established rights of access and use for common people to the forests of Britain.Most of us know how “good” trees are for the urban environment, and for the planet overall.Whether you’re a human, an insect, a fungus, a bat, a bird, a four-legged omnivore, or an amphibian, we all love trees.They determined the varying contribution of VOCs from vegetation to ozone levels in Berlin as follows: ~9 – 11 percent on average days in June and August, ~17 – 20 percent on average days in July, and ~60 percent during the heat wave.Researchers have reported that there are “crucial knowledge gaps associated with exacerbated emissions of pollen and volatile organic compounds, which may increasingly contribute to tropospheric ozone and particle formation under future climatic conditions” (Grote et al., 2016).Issues such as allergens, ozone formation, and how plants deal with particulate matter play an important role in the quality of the urban atmosphere.Like most living things, plants emit volatile organic compounds, or VOCs, in the form of evaporated vapour or as sublimated solid resin.