City Trees

Trees Over Time Series: Most of us have knowledge of an unlikely recovery in ourselves, our friends or family. Personally, I am very lucky to have recovered well from a very serious spinal injury whereby I could not feel the lower part of my body due to a disc in my spine impinging rather severely on my spinal cord. I am very grateful for the skills of the neurosurgeons that operated on me at two in the morning, after I rapidly signed off a set of consent forms without reading them. Despite some short and mid-term side effects, all my facilities and functions now work fine. My doctor even commented that this level of recovery from such an operation was unusual: a badge of honor (if not earnt)! Unfortunately, high-impact sport and exercise is now not recommended for me; looking at it more positively, I have got a good excuse never to run a marathon. This article, based on my "Trees over Time" project, looks at some unlikely recoveries within trees, from the occlusion of wounds to the reshaping of a tree's crown. This is far easier to illustrate in younger trees whose growth rate is fast and where changes are rapid. However, I am playing the long game with this hobby of mine and am tracking changes in many old trees, too, because I think that all trees have a lot to teach us. There are three key parameters for a recovery to occur in a tree. First, the root system must be sufficiently developed and healthy to support any recovery efforts. In the UK, nearly all native trees can be coppiced (cut to a low stump) and then they re-grow, empha- sizing the great importance of a tree's root system for tree health and its ability to grow (and re-grow). Conserve a root system and one often saves a tree. Second, and very fortunately, photosynthesis is a highly efficient process and produces a lot of non-structural carbohydrates pretty quickly. The leaves of the average tree, for instance, can pay back their own "construc- tion costs" in less than a fortnight of fine weather. Third, and highly related, is the way in which all woody parts of a tree can act as stores for those non-struc- tural carbohydrates arising from photosynthesis—and these can then be mobilized to provide the necessary resources for growth and recovery when needed. This is a bit like a government having a national reserve of funds for emergencies; if only the UK's government would take note of how successful that strategy is! These eight "Trees over Time" series images are amongst my favorites so far captured in the "Unlikely Recoveries" sub-category. Text and photos by Dr. Duncan Slater, Senior Lecturer in Arboriculture at Myerscough College, Lancashire, England Unlikely Recoveries 30 CityTREES Dr. Duncan Slater is Senior Lecturer in Arboriculture at Myerscough College in Lancashire, England. Duncan is the tutor for the MSc in Arboriculture and Urban Forestry online course, run at Myerscough College and validated by the University of Central Lancashire. Duncan currently holds five university degrees, including a PhD in Plant Sciences from the University of Manchester, and he is working on a sixth, an MSc in Environmental Management from the Ecology Department of Ulster University.

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