Disease, aging, and root-growth

This edition of the Arboricultural Journal includes three major papers which present three significant but widely differing contributions to arboricultural science each one addressing a key matter of interest. Jonathan Lageard used a mixed methods approach to gaining evidence for the growth and age of mulberry trees planted at The Charterhouse in London. This provides a helpful insight into the dating of planted fruit trees and into the use and application of different sources of information to aid the process. A rather different piece of research is reported by Peter Del Tredici (Del Tredici, 2022). Again, addressing a very neglected topic, Del Tredici considers the generally neglected subject of endocormic roots and their development and function. These structures are a form of adventitious root growing inside older trees with significant heart-rot and in fact are very important in terms of tree and growth. Furthermore, the phenomenon of endocormic root growth appears to be highly significant in smaller veteran trees such as hawthorn, birch, and rowan; a topic to be reported on in due course. This present paper provides a remarkable insight into what is currently known and of the history of the study of these poorly understood roots. The author also suggests the term “epicormic” be extended for adventitious roots where branches meet the ground. The study touches on several rather neglected topics including hollowing of veteran willows, and suckering/rooting of branches and fallen trunks especially in wet landscapes. Much of this takes us beyond the typical research into ancient and veteran trees and helps open up new lines of investigation and of discovery. Finally in terms of the papers, another hugely important topic at present is the spread of often catastrophic tree diseases. For those interested in or concerned by exotic Phytophthora infections, Andrew Walton and Andrew Smith have presented a wide-ranging review of literature on natural resistance to infection. This is a very important topic and with climate change and increasing globalisation the problems will certainly get worse rather than better in the decades to come. Insights provided by such reviews are therefore welcomed and particularly helpful. The issue ends with a letter to the editor from Peter Sterken (Sterken, 2022) addressing the matter of compression forks and axioms, and finally with book reviews.