Wednesday Speakers 2017

Biography

I joined Forestry Commission England in 2010, and have an operational role in the national Tree Health team, protecting England’s trees against pest and disease threats. I am primarily involved in the surveillance and detection of quarantine pests and diseases; I have field-level experience of various tree pests and diseases, including numerous phytophthora species, Asian longhorn beetle, sweet chestnut blight and oriental chestnut gall wasp to name a few. A registered Plant Health Professional, I provide training in surveillance and symptoms identification, and I'm currently studying towards a post-grad qualification in forest pests and pathology.

Abstract

An overview of the fungal pathogen Sweet Chestnut Blight, following the recent findings on trees in south-west England. Presentation to include an update on the UK situation, and in addition a brief background, examples of symptoms and a guide to identification, an idea of impacts and the implications for biosecurity.

Biography

Dr. Paula Shrewsbury received her B.S. in Plant Science from the University of Rhode Island, a M.S. in Entomology from the University of California, Riverside, and a Ph.D. in Entomology from the University of Maryland. Paula is an Associate Professor and Extension Specialist in Entomology at the University of Maryland, USA. Paula has conducted applied research and extension education programs towards furthering the development and adoption of Integrated Pest Management for over 25 years. The overall focus of her program is to create sustainable landscapes, nurseries, and turf systems with an emphasis on biological control and invasive species.

Abstract

Introductions of exotic, invasive species is on the upswing world-wide, many of which are devastating economically and ecologically. Approaches including classical biological (release of natural enemies from the pest insect’s native range into the introduced region) and conservation biological control (use of natural enemies native to the introduced range to suppress the pest insect) have the greatest likelihood of providing long term, sustainable suppression of invasive insects. Understanding the role of indigenous and exotic natural enemies is critical toward the success of biological control.

This talk will present research efforts to elucidate the influence of both indigenous and introduced exotic natural enemies against emerald ash borer (EAB), Agrilus planipennis, and brown marmorated stink bug (BMSB), Halyomorpha halys. Several parasitoids native to the U.S. have been found parasitizing EAB larvae. In addition, 4 parasitoids (tiny wasps) from EAB’s home range of Asia have been released in the U.S. since 2007 including the egg parasitoid Oobius agrili, and 3 larval parasitoids (Tetrastichus planipennisi, Spathius agrili, and in 2016 Spathius galinae). Tetrastichus planipennisi has established and dispersed in many regions of the U.S. Life table studies of EAB have identified the impact of mortality factors on EAB in infested ash trees. Historically, parasitoid releases have been conducted in natural stands of ash. More recently we are elucidating the impact that habitat factors have on EAB natural enemy activity along an urbanization gradient. Studies of indigenous natural enemies attacking BMSB in natural, fruit and vegetable, and soybean plantings have found that the complex and impact of parasitoids and predators vary by habitat type. Information from studies of biological control of invasive insects in the U.S. will help inform government agencies and practitioners worldwide in sustainable management approaches for these invasive species.

Biography

Graduating from Plumpton College with an FdSc in Arboriculture in 2008, Geoff continued his work in tree surveying and arboricultural consultancy for 5 years. In 2011 he undertook an MSc in Conservation and Forest Protection at Imperial College London, designing his own study to evaluate the effect of different arboricultural works on the vitality of veteran oak pollards for his thesis. His vitality scoring system is being used on a forest wide survey by the conservation team at Epping Forest. From 2012-2015 he worked at Treework Environmental Practice where he further developed his specialism in veteran tree surveying as well as working on research projects looking at AOD and Massaria. He joined Guildford Borough Council as Tree and Woodland Officer in 2016.

Abstract

A synthesis of observations made together with Neville Fay are presented. These consider various populations affected by Chronic Oak Decline (COD) and Acute Oak Decline (AOD) in England over the past decade. They also take account of research into oak decline in continental Europe, and results from a five-year study on AOD in the Royal Parks, London.

The evidence highlights similarities between COD and AOD and points to a continuum that reflects different expressions of a disease complex, rather than two distinct, discernible conditions. Environmental influences on tree root function and disease susceptibility are explored, particularly with respect to rhizosphere hydrology, and soil microbiology and plant-microbe interactions.

Globally, anthropogenic pollution inputs are significantly influencing soil microbial communities, and are in turn driving changes in above-ground plant community compositions. This has potential to affect selection pressure upon individual species. We hypothesise that oak may be one of a range of species so affected, in this case manifesting as oak decline. Possible indications of similar effects upon other tree species are briefly considered, with the implications of our findings and hypothesis discussed in relation to tree health in general and to terrestrial biodiversity.

Biography

Glyn is an experienced environmental economist who has worked on a range of environmental projects including the mid-term evaluation of the Rural Development Programme, projects on greenhouse gas mitigation methods in relation to the agriculture industry, and a number of projects on invasive species. Prior to his environmental work, Glyn worked in finance and micro and macro-economics, which gives him a broad view of policy issues across voluntary, economic and regulatory schemes. Glyn is currently engaged in a number of projects relating to the social and economic impacts of plant and tree pests and diseases and sustainable intensification/mechanism options for agriculture.

Abstract

Ash Dieback presents potential problems on a scale not seen since the Dutch Elm Disease (DED) outbreak in the 1960’s and 70’s. Unfortunately, many of the tree professionals who dealt with DED are not working in the profession any longer, leaving a knowledge gap for the current generation of professionals who will have to deal with the problems created by Ash Dieback. Since 2014 The Tree Council and Fera have undertaken, a wide-ranging investigation of the potential problems that Ash Dieback will cause to the owners and managers of non-woodland trees. In this presentation, we will provide a summary of the current information available about Ash Dieback in non-woodland trees, explain about the development of Ash Dieback Local Action Plans and show the structure of a ‘toolkit’ that's is being developed to help deal with the problem in non-woodland situations. We will also show results on work carried out to investigate alternative funding methods to pay for a resilient treescape and the importance of developing tree strategies to ensure that a healthy treescape is maintained.

Biography

Jon Stokes is Tree Council’s Programme Director. He was responsible for establishing The Tree Council’s Tree Warden Network which now has 8000 volunteers. His work includes representing the Tree Council’s on the national policy committees for tree health, tree safety, orchards, wood-pasture, woodlands and hedges and is leading the organisation’s research on Ash Dieback in Non-Woodland Situations.

Abstract

Ash Dieback presents potential problems on a scale not seen since the Dutch Elm Disease (DED) outbreak in the 1960’s and 70’s. Unfortunately, many of the tree professionals who dealt with DED are not working in the profession any longer, leaving a knowledge gap for the current generation of professionals who will have to deal with the problems created by Ash Dieback. Since 2014 The Tree Council and Fera have undertaken, a wide-ranging investigation of the potential problems that Ash Dieback will cause to the owners and managers of non-woodland trees. In this presentation, we will provide a summary of the current information available about Ash Dieback in non-woodland trees, explain about the development of Ash Dieback Local Action Plans and show the structure of a ‘toolkit’ that's is being developed to help deal with the problem in non-woodland situations. We will also show results on work carried out to investigate alternative funding methods to pay for a resilient treescape and the importance of developing tree strategies to ensure that a healthy treescape is maintained.

Biography

Professor Andreas Roloff is head of the chair of Forest Botany since 1 January 1994 and works with his team all over the spectrum of forest and urban tree topics (tree biology), botany of woods, successional development and parks. His favourite scientific interest is to understand trees in their complete broad life cycle and adpatation mechanisms, not only parts of it and some special elements.

That covers the teaching, too. For this the direct structural connection to Tharandt Botanic Garden/Saxony State Arboretum is important and helpful, as he is director of this institution as well. His personal main research areas are urban trees and drought stress: there are so many questions and problems, and special know-how is essential for these subjects. Beside presentations on scientific meetings the chair is organizer of the annual Dresden Urban Tree Conference (Dresdner StadtBaumtage) every year in March, together with Dresden green space management.

The more we know about the character of many native and foreign woody species, the better we can manage, maintain, protect and use them. E.g., climate change has the consequence of modified strategies of tree maintenance and species selection, with strong importance to consider the tree's adaptation potential and plasticity. Future with trees.

Chair of Forest Botany
Director of Institute of Forest Botany and Forest Zoology
Director of Tharandt Botanic Garden

Abstract

In this presentation general methodical problems of vitality assessments of deciduous trees are discussed; existing disparities or contradictions are pointed out if assessments based on 'leaf loss' and based on crown structures are compared. The necessity of considering the branching pattern is substantiated and the methods developed to date are presented.

With the help of the 'shoot base scars', it becomes possible to reconstruct the crown development of the last 10 years, and in some species of decades. In every investigated (broad leaved) tree species there are four growth stages to discriminate: exploration, degeneration, stagnation, and resignation. These stages, which result in fundamental modifications of the branching structure, are due to (statistically significant) decreasing shoot lengths. Especially in the leafless state these different branching structures in the treetop are perceived from a distance (and in aerial photographs, as well). They are the basis of vitality assessment in four vitality classes. By using this approach which is based on branching structures a long-term chronic decrease of vitality can be recognized. Therefore, it is a practical method to use in detecting stress and decline in urban and forest trees. This method has been tested and confirmed in many studies and is now used in European countries for urban and forest tree assessment.

To interpret the results correctly, the tree age should be taken into consideration. A proposal for this approach is demonstrated.

Biography

Adam is owner and Principal Consultant of The Tree Doctor, a Brisbane, Australia based consulting and contracting provider. Adam spent his early years on the family farm falling out of trees and annoying the local wildlife. Upon completing his studies in Plant Sciences at UNE he worked briefly for the NSW Forestry Commission but rapidly grew bored with Pinus monoculture forestry. He moved to Brisbane in 1986 where he partied too much, slept too little and, when otherwise not preoccupied, managed the sourcing and transplant of mature trees and palms into domestic and commercial landscape projects for a large landscape construction and maintenance company. After several years of making money for other people, he decided to make some for himself and in 1992 began trading as ‘The Tree Doctor’ providing specialist tree care and consulting services.

The Tree Doctor provides tree care services to many high profile sites including Parliament House, Brisbane; the Queensland Cultural Centre and The ‘Dig Tree’ at Cooper Creek. The Tree Doctor has also completed some of the largest tree transplants undertaken in Australia.

After 30 years in the industry and 25 years after establishing The Tree Doctor, Adam is still broke, can’t afford to join the AA and probably should have been a farmer.

Abstract

The transplanting of trees and palms within the urban landscape has been occurring for several hundred years. The advent of modern machinery, particularly small and easily established mobile cranes and improved excavation methods, has further simplified the process. By the late 1980s, most commercial landscapes in urban areas contained several to many transplanted palms and trees, with the relocation of much larger specimen trees becoming more frequent.

The lifting and movement of trees weighing in excess of 100 tonnes is always a challenge and methods used to overcome these challenges have improved markedly. Now trees of several hundred tonnes in weight can be more easily relocated, provided suitable sites are available and a desire to provide a legacy for those after us is present.

Biography

Duncan is the course tutor for the MSc in arboriculture and urban forestry, taught on-line at Myerscough College, Lancashire, England.

Duncan specializes in teaching urban forestry, woodland management, tree risk management, tree and shrub planting, plant identification and the management of pests and diseases of woody plants. Duncan is a current candidate for a Masters in Education from the University of Central Lancashire.

Duncan is a chartered forester (MICFor) and a member of the Arboricultural Association (MArborA).

Abstract

The very strong association between natural bracing in trees and the formation of weak, bark-included junctions has only recently been reported. During the delivery of eleven industry training workshops in August – September 2016, 348 members of the arboricultural industry, mostly based in the UK, were supplied a questionnaire on the management of trees with the focus being on bark-included junctions. The outcomes of this industry survey are reported, further to a summary of the latest research work on natural bracing in trees and its impact on common tree management practices.

Biography

Steffen Rust is Professor of Arboriculture at the University of Applied Science and Art in Göttingen, Germany. His main field of research are non-destructive methods for tree risk assessment. Steffen is one of the developers of stress wave tomography. Recent studies concentrate on ground penetrating radar, electrical resistivity tomography for stems and root systems, as well as static pulling tests and analysis of tree dynamics in natural winds.

Abstract

The presentation demonstrates a new method to assess the anchorage of urban trees by quantitative analysis of the relationship between root plate inclination and regional wind data.

We studied whether wind data from regional weather stations can be used to find the correlation between wind speed and root plate inclination. We tested more than 200 trees in 57 storms in 3 years using tilt sensors installed at their base.

Our analyses show that wind speed data can be taken from weather stations several kilometres away from the tree. The quality of the wind speed-tilt correlation does vary, depending on local conditions and topography.

The tree's reaction to wind can be extrapolated by 10 km/h beyond the measured maximum wind speed in many cases. The reliability of the extrapolation can be assessed statistically.

The shape of the curve fitted to the wind and tilt data allows differentiating safe from unsafe trees in wind events of 50 to 60 km/h.

Based on techniques from static pulling tests, our approach can be used to estimate the wind speed at anchorage failure.