Wednesday, October 24

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Concurrent Session Track A: Climate Change and Urban Oak Landscapes

Utilizing California’s Climate Change Legislation to Keep Oaks Standing
Oak woodlands and oak-forested lands cover approximately one tenth of California’s landmass. The state’s oak ecosystems are disappearing, especially those that grow at the interface of urban, agricultural, and wilderness environments. These oaks are threatened by sprawl, over-grazing, agricultural business expansion, systemic drought, disease, and wildfire—pressures that are exacerbated by the impacts of climate change. California has lost more than a million acres of oak-related lands over the past seven decades, with an estimated 20 percent of the state’s oak landscapes facing development threats by 2040. California’s statewide oak protections are limited, with county-level protections highly variable. Yet, the state’s climate laws, combined with California Environmental Quality Act (CEQA), are legal tools to keep oaks standing and to mitigate for their loss. The California Oaks program at California Wildlife Foundation and our California Oaks Coalition partners are utilizing the state’s ambitious goals for the reduction of greenhouse gas emissions to challenge the conversion of oak woodlands and forests. Net present value of greenhouse gas emissions forms the foundation of the state’s greenhouse reduction objectives, as well as the California Forest Protocol preservation standards. Every ton of carbon dioxide released into the atmosphere by oak woodland or forest conversion—alongside the loss of the woodland’s or forest’s role in carbon sequestration—represents a measurable potential adverse environmental effect, which is covered by CEQA. Thus California requires the analysis and mitigation of greenhouse gas emissions associated with proposed oak woodland or forest conversions.

Angela Moskow

Angela Moskow is California Oaks Information Network Manager at California Wildlife Foundation (CWF), an organization committed to conserving, restoring, and maintaining habitats and corridor linkages to ensure the biological diversity of the state’s species over time. Her duties include the development of California Oaks Coalition, which brings together local, regional, and state organizations to conserve and perpetuate the state’s primary old growth resource, and the publication of "Oaks," a semiannual newsletter that reports on CWF programs and oak issues throughout the state. Her earlier posts include Urban Sprouts (conducting community and garden-based education in San Francisco), The Bay Institute (promoting the ecological health of San Francisco Bay and its watershed), University of California (UC) Small Farm Center, and UC Genetic Resources Conservation Program. She earned a Bachelor of Arts in Environmental Studies and Philosophy from Oberlin College and a Master of Science in International Agricultural Development from UC Davis.

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Urban Oak Landscapes of the Future

What role will oaks play in the urban landscapes of the future? Currently, over half of the global human population lives in urban areas, and some projections anticipate that this will increase to two-thirds by 2050. Trees are vital to enhancing the quality of life in cities, as they provide many environmental, economic, and socio-cultural benefits. Yet to provide these benefits in a substantial way, urban trees need to grow well and survive for long periods. Unfortunately, trees surrounded by pavement are usually short-lived. Some studies have found the average lifespan of city street trees to be as low as 10 years. Elevated temperatures, drought, and degraded soils are just a few of the reasons for their early demise. These challenges have led to a diversification of the trees planted in cities, yet the species utilized should still be tolerant of stressful urban conditions. Matching a tree species to the environment of the planting site is key to success. As a genus, Quercus is often under-represented in cities (at least in the northeastern United States). When oaks do compose a considerable proportion of the urban forest, it is usually due to only a few species of Quercus. This is surprising, as the genus is so large and diverse, and oaks in general often have the reputation of being stress-tolerant. So why aren’t oaks better represented in urban tree plantings? And how can quercophiles encourage the greater use of oaks in future urban landscapes?

Bryan Denig

Bryan Denig is a visiting fellow at Cornell University’s Urban Horticulture Institute. He works under the guidance of Dr. Nina Bassuk, a leader in the field of urban tree establishment, and his main research focus is the selection, evaluation, and propagation of hybrid oaks. He is also part of a team currently working on developing a management plan for the American elms that compose the National Mall in Washington D.C., and he helped to develop a comprehensive urban forestry plan for the City of Ithaca, New York. Bryan is also a designer at a landscape architecture firm, where he works on a diverse range of projects.

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The Difficulty of Planting Urban Trees in France Under Climate Change
The high temperatures that are beginning to affect us mean that trees will have to be planted more than ever in order to provide people with healthy shade. From nurseries to garden or street designers to the horticultural press, the vast majority of actors involved in urban spaces don’t seem to have grasped the true consequences of climate changes. The teaching given to landscape architects no longer includes knowledge of the ecological requirements of ornamental species, the nursery profession is in threatened by the hegemony of garden centers, the main objective of which is much less the diversification of plants than the large-scale sale of plants of a limited number of species and the ignorance of the necessary genetic diversity and health problems brought by pests from other continents should motivate us to act differently. In addition, the urban and garden trees are the victim of bad management, probably inherited from ""Jardins à la Française"" and its certain notion of nature mastery. The rapid evolution of the climate towards an arid trend should not make us forget that our geographical situation in a temperate climate implies that the winters, although shorter, are not necessarily less cold and that the range of plants to be used in the future must consider all these parameters.

Thierry Lamant

Forest technician, dendrologist & arborist, IOS member since 1997 and vice-president between 2000 and 2003, co-author of the illustrated guide of oaks.

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Concurrent Session Track B: Global Oak Conservation

Patterns of Oak Diversity and Structure Along an Elevation Gradient in Mixed Pine-Oak Forest in Oaxaca, Mexico
The state of Oaxaca is a center of oak diversity, and in the Central Valleys (Valles Centrales) region of the state, oak species are a major component of forested ecosystems. Depending on elevation and microclimate, oaks in the mountains of this region are either dominant or co-dominant with pines. A recent study modeling the vulnerability of Oaxaca's major vegetation types to climate change predicts increased climatic exposure in these mountains, which is likely already starting to cause changes in the distribution of the principal species. To evaluate whether there is evidence of distribution shifts and, if so, to quantify by how much and for which species, we set up a series of ten 50 x 50 m long-term monitoring plots at 250 m altitudinal intervals along a 1000 m elevation gradient. All woody stems greater or equal to 5 cm DBH were tagged and temperature and humidity data loggers were placed in each plot. In addition to species presence along this gradient, we are interested in how basal area, relative abundance, and abundance by size class may be changing, and how understory composition may differ from that of the canopy. We present the preliminary results of our findings and discuss implications for ecosystem services and the community managed reserve where this forest is located.

John N. Williams

CIIDIR-OAXACA, Insituto Politécnico Nacional, Mexico

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New Efforts in Mexican Quercus Conservation
Maricela Rodríguez-Acosta, Allen Coombes, Susana Valencia

With close to 170 species and almost 100 of these endemic, conservation work on oaks in Mexico is very important and in spite of recent advances, there is still much to be done. This we attribute to a lack of a systematic exploration to determine the exact distributions of the species. Our garden has made efforts in conservation since 2000, and completed two examples of assessment for conservation with the support of FFI: Q. hintonii and Q. insignis, two endangered species. In this project, we decided to increase field exploration in Puebla by making regular field trips to the most remote and under-collected places, to find unreported species and increase knowledge of the distributions of others. We eliminated two species previously reported for Puebla and four unreported species were found, giving a total of 52 species for Puebla, the same as Oaxaca. This result comes from the institutional commitment for conservation and the inter-institutional support that is helping to achieve our goal, participating in the Oaks of the Americas Conservation Network. Intensive work has been carried out on Q. hirtifolia and detailed maps have been produced, showing its limited distribution and special habitat. The results show the need to support botanical exploration at a national as well as a state level, and that this approach will show distributions for the 52 species in Puebla, how they relate to national populations and which are the candidates for conservation assessment.

Maricela Rodríguez-Acosta

Maricela Rodríguez-Acosta received her PhD in Plant Sciences from Southampton University, UK. She is founder of Puebla University Botanic Garden, which, since 1995, has been working on establishing an oak collection in Puebla, now the best in Mexico. The Garden has participated in oak governmental reforestation in Puebla State. In 2000 and 2001 she was involved in threatened Quercus assessments at a national level, with Q. hintonii and Q. insignis, two native Mexican oaks, and is now is focusing on Q. hirtifolia. In 2009, she organized the sixth International Oaks Conference in Puebla. Currently, she is interested in restoration of a University Campus using native oaks and in continuing to develop the oak national collection in the Botanic Garden. She is committed to carrying on field exploration in Puebla and surrounding states, in order to finish work on Trees of Puebla, of which oaks are valuable components. 

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Mapping the Elevational Distribution of Oaks in the Eastern Himalayan Mountains

Thorne, JH, H Choe, RM Boynton, D. Wangdi, L. Dorji

Bhutan is located in an important nexus of the Himalayan Mountains, between the eastern Himalaya and Hengduan Mountains of Southeast Asia and the central and western Himalayas of Nepal and Kashmir. Bhutan’s floristic species composition is influenced by at least four floristic regions; the Indian, Indo-Chinese, Sino-Japanese and Central Asian, and it includes the ecotone between the Holarctic and Paleotropic plant kingdoms. The fine-scale patterns of plant diversity within the Himalayan Mountains and their various sources of origin challenge ecologists and biogeographers endeavoring to account for the patterns and sources diversity across the region. Bhutanese foresters recently completed a National Forest Inventory (NFI) covering 1685 forest plots that provide location data for 569 species of trees and shrubs in this central part of the Himalayan Arc. We used the NFI it to assess species elevational distribution from 132-4560 m. The NFI documents 17 species of trees in the Fagaceae, including seven Quercus, with three in tree or shrub form. This talk presents their elevational distribution and discusses their likely sources of origin.

James H. Thorne

Research Scientist, Environmental Science and Policy, University of California, Davis

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The Conservation of Quercus ilex ssp. rotundifolia in the Dehesas of the Southwestern Iberian Peninsula
The dehesa is a man-made ecosystem found in the southwest of Spain and Portugal, with the Holm Oak (Quercus ilex ssp. rotundifolia) as the most abundant tree species. These particular oaks can produce large crops of low-tannin edible acorns suitable for inclusion in the human diet. There is a wide variation in the size and tannin content of the acorns of the Holm oak trees. In the last few decades several threats have emerged that have affected the Holm oaks to the point where their number has been rapidly decreasing. Why this area has an abundance of Holm oak trees with a low tannin content in the acorns is unknown. Neglect and a lack of good conservation practices has seen the regeneration of the species greatly reduced. The aim is to conserve the trees with low tannin acorns and reproduce them vegetatively by planting them on a conservation site. In the provinces of Extremadura in Spain and Alentejo in Portugal, a team will investigate different dehesas and examine trees for the tannin content of the acorns over a period of 5 years. From trees that show a low tannin stability, cuttings will be taken from lateral branches, rooted in a nursery and planted on a conservation site. The trees with low tannin acorns will be further reproduced and made available for planting for agroforestry purposes as human and animal food.

Hendrik Brand

Hendrik Brand has studied the use of acorns as human food with a specific focus on the Holm oak in Spain and Portugal. He is a botanist and has worked on edible acorns since completing his studies at the University of Kassel in Germany. In 2014 after researching the subject he made a short video on acorns used as human food in Spain https://vimeo.com/88583692. His goal is to promote the inclusion of acorns in the human diet and the integration of edible oaks in the agricultural landscape. Hendrik has a Bachelor degree of Sciences in organic agriculture. He grew up in the Netherlands, has worked for the Tropical Greenhouse of the University of Kassel and the Northwest German Forestry Research Institute. In 2016-2017 he lived in Tasmania, Australia where he worked on developing horticultural projects.

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Concurrent Session Track A: Oak Utilization and Cultural Landscapes

Working with Beautiful Oaks to Produce Delicious Truffles
This talk will describe an oak-centric project in the Willamette Valley of Oregon. This project has been ongoing since 2008, its goal being to produce three species of black truffles (Tuber melanosporum, T. uncinatum, and T. macrosporum). The species of oak involved are Quercus pubescens, Q. ilex, Q. cerris, and Q. robur. The project has also involved Carpinus betulus, Corylus avellana, C. colurna, and Fagus sylvatica. The project has followed recent progress in trufficulture from France and Italy, generally known as "trufficulture raisonnée,” best translated as data-driven trufficulture.

Bogdan Caceu

Bogdan began farming in 2008 in the Willamette Valley of Oregon, where he has planted four species of oak inoculated for black truffle production. He also grows 17 varietals of olives for production of extra virgin olive oil. Since 2016, Bogdan has served as Executive Director of Olive Growers of Oregon (OGO), the nonprofit growers’ association. He also serves on the Advisory Council to Oregon State University’s olive research project. In his spare time, Bogdan is managing director of Be Diligent, Inc., a due diligence and policy analysis firm. 

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Tribal Traditional Knowledge, Stewardship of Tanoaks, Cultural Landscape Practices and Climate Adaptation: Sustaining a Future of Acorn Traditions and Food Security in the Klamath-Siskiyou Bioregion, Western United States
Tanoak acorns (Notholithocarpus densiflorus) continue to be a cultural food staple of American Indian tribes in the Klamath-Siskiyou Bioregion. Tribal traditional knowledge of tanoaks includes changes with climate, fire regimes, and forest dynamics coupled with cultural adaptive stewardship practices. Recent prolonged drought, wildland fires, and other climate and non-climate threats and stressors are affecting not only tanoak acorn production, but also the tribal cultures who depend upon the oaks across the landscape that provide a range of cultural ecosystem services. The objective of this research was to synthesize the available traditional and western scientific data about tanoak stewardship practices to promote acorn food security. A cross-scaled research framework was developed to investigate which metrics and indicators are important for assessing changes in the condition of tanoak co-dominated forests across the landscape, tribal tanoak orchards, individual heritage trees, and for acorn food use quality. Trial field experimental research approaches integrated tribal and western scientific knowledge of the desired ecological conditions for tanoak forests, factors supporting acorn production and tribal gathering opportunities of orchards, and tree specific characteristics. This cross-scale, interdisciplinary, multiple methods research approach provides insights about climate and fire effects on acorn production. The range of methods include aerial LiDAR to characterize forests, acorn gathering site condition surveys, tribal acorn foraging trials, and individual acorn quality assessments. This information is informing current tribal food security associated climate adaptation strategies. Tribal knowledge and stewardship practices of the Karuk and Yurok Tribes of northwestern California are used as case study examples. 

Frank K. Lake

Frank received a Bachelor of Science degree from University of California-Davis (1995) in Integrated Ecology and Culture with a minor in Native American Studies. In 2007 he completed his Ph. D. graduate degree from Oregon State University, Environmental Sciences Program. He works on tribal and community forestry and related natural resource issues. His research focuses on restoration ecology and the incorporation of traditional knowledge into wildland fire and forest management in the Pacific Northwest and northern California, with an emphasis on the Klamath-Siskiyou bioregion. He has a research interest in wildland fire and management effects on tribal acorn food systems. Recently, his focus is how tribal traditional knowledge can be incorporated in to scientific climate change and food security research to support tribal adaptation and mitigation strategies. Frank serves as a science advisor to The Nature Conservancy’s Indigenous Peoples Burning Network and for the Western Klamath Restoration Partnership. 

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Chasing a Lost Black Oak on Santa Cruz Island, California
Jonathan W. Long, Richard Dodd, John Knapp, Angel Fernandez i Marti

We investigated reports of a hybrid black oak from Santa Cruz Island to determine implications for natural history and restoration. California black oak hybridizes with some live oaks to form distinctive trees with persistent leaves. A recent review on restoring black oak noted a collection of oracle oak (Quercus × morehus) from the island, which was peculiar because neither black oak nor the other parent, interior live oak (Quercus wislizeni), are known from the Channel Islands. We analyzed DNA from one of the five samples of the hybrid collected in 1931-1932. We then located three apparent black oak hybrids in the summer of 2017, from which we conducted additional genetic analysis. The nuclear and chloroplast DNA results suggested that the DNA was closest to coast live oak (Quercus agrifolia) and Santa Cruz Island Oak (Quercus parvlua), which are both common on the island. This results suggests that the hybrid might be considered Chase oak (Quercus × chasei), which is a cross of black oak and coast live oak. We consider whether birds or Native Americans may have brought acorns of either the hybrid or California black oak to the island, as has been suspected for a number of other plant and wildlife species that are found on the islands, or whether long-distance pollen might explain the hybrid. Resolving the identity of these hybrids remains a work in progress, due the complexity of these introgressed populations and need for additional sampling. In addition to suggesting that black oak has some unusual twists in its natural history, our findings prompt questions about restoring this remnant oak population.

Jonathan W. Long

Long is a research ecologist with the Pacific Northwest Research Station in Davis. He leads a variety of interdisciplinary research projects to help managers restore forests and wetlands to support important social and ecological values. In recent years, he has produced a report of restoring California black oak in a partnership with the North Fork Mono Tribe, has studied the effects of large fires on forests and watersheds, and has developed science-based strategies for restoring forests landscapes in the Pacific West. He has worked  previously for the Rocky Mountain Research Station, University of Arizona Cooperative Extension, and the White Mountain Apache Tribe in Arizona.

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Cork Wars in World War II: Oaks, Espionage and National Security
This talk shares a compelling piece of oak history and California. In the 1940s, when cork was a modern material crucial to America's war effort, 4-H clubs and state governors planted cork oaks like the ones on the University of California, Davis campus, to make the country free of its dependence on foreign sources.  By 1940, the United States imported nearly half the world’s production of cork, for industries ranging from bottle caps to automobiles and bomber airplanes. When Germany blockaded the Atlantic and cut supplies, the cork shortage became a threat to national security. And when a devastating factory fire in Baltimore, Maryland stirred a Federal Bureau of Investigation inquiry for sabotage, the entire cork industry was pulled into the war effort. From espionage in Portugal to a nationwide tree growing campaign led by a forestry professor at University of California, Berkeley, the talk draws on my new book, CORK WARS: INTRIGUE AND INDUSTRY IN WORLD WAR II, to be published in November 2018 by Johns Hopkins University Press. This talk looks at the system from Portugal’s montado oak forests to Baltimore and that nationwide tree-growing campaign, which had a dozen state governors brandishing shovels for a patriotic cause. And will examine the dynamics of wartime intelligence and environmental security. Conference participants will get an inside look, from pursuing survivor interviews to submitting FOIA requests and uncovering declassified records. 

David Taylor

Taylor has written award-winning histories including Soul of a People: The WPA Writers’ Project Uncovers Depression America (Wiley) and Ginseng, the Divine Root (Algonquin), as well as documentary films. His work appears in the Washington Post, Smithsonian and other publications. He teaches science writing at Johns Hopkins University and lives in Washington, DC.

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Concurrent Session Track B: Plant Collections and Public Garden Conservation Initiatives

Plant Collections Network Multisite Quercus Collection: Collaborative Efforts from 2015-2018
In 2007, fifteen gardens were inducted into the American Public Gardens Association Plant Collections Network (then North American Plant Collections Consortium) to form the multisite Quercus collection, the Network’s first multi-institutional collection. Over the past decade, the group has expanded in size to include nearly twenty botanical gardens and arboreta across North America. In recent years, scope and activity of the group has further increased through collaborative projects between member institutions and the USDA Forest Service to identify species of conservation concern, collect them from the wild, and distribute them across the network to aid in their ex-situ conservation. Furthermore, the combined inventory of the group has been standardized, streamlined, and utilized by The Morton Arboretum, Botanic Gardens Conservation International, and other groups to assist with red-listing activities, and to identify gaps in overall cultivation of several species. Future efforts will focus on setting priorities for acquisition based on gap analysis, recruiting member institutions in geographic areas that can reliably grow such species, and further making inventory data available for ease of access and analysis.

Matthew Lobdell

Matt Lobdell has served as Head of Collections and Curator of The Morton Arboretum since 2014. There, he is responsible for overseeing the maintenance and development of the Arboretum’s plant collections. In 2017, Matt began serving as the Group Coordinator for the Plant Collections Network Multisite Quercus collection, following the completion of a two-year term as coordinator for the multisite Magnolia collection. Matt has participated on numerous seed-collecting expeditions covering the Southeastern United States, Pacific Northwest, and South Caucasus regions. He has previously been employed in a variety of curatorial and horticultural capacities at the Polly Hill Arboretum, the Arnold Arboretum, University of Delaware Botanic Gardens, and Moore Farms Botanical Garden. Matt holds a B.A. from Kenyon College, a M.S. in Plant and Soil Science from the University of Delaware, and serves on the Board of Directors of Magnolia Society International.

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Cultivated Oaks of the World: Putting Oak Collections on the Map
Roderick Cameron, Allen Coombes

Over recent decades, significant collections of Quercus have been established in different parts of the globe. Together, they constitute a valuable conservation resource and deserve to be documented and shared in a way that is easily accessible to interested parties. The Cultivated Oaks of the World project aims to create a database of major oak collections around the world, aggregating data provided by each collection and using a simple format that allows for easy input and includes straightforward filter and search features. In addition, geolocated trees can be automatically mapped and the various collections viewed on a map of the world.
The project was initiated in 2016 by Allen Coombes. Currently the project uses Google Fusion Tables, an experimental data visualization web application that gathers and shares data tables. Data is stored on Google Drive and can be easily accessed by users using a Google ID.
The project is closely aligned with the goals of the IOS, one of which is to facilitate the location and distribution of living material for propagation of oaks. An aggregated database will assist in ex-situ conservation, as it would allow us to see at a glance which living specimens are being preserved and what their origin is, so as to determine whether the genetic diversity of a species’ population is fully represented in collections. As we can see where the specimens are growing, we could also judge whether there is sufficient geographical diversity to mitigate risks posed by climate change and potential pathogens.

Roderick Cameron

Roderick Cameron became interested in oaks on inheriting his father’s oak collection in 2008, and has served on the Board of the International Oak Society since 2012. As curator of the arboretum started by his father, he has had experience building a database for an oak collection, and has published it online, recently adding a map feature. He became involved in the Cultivated Oaks of the World project in the early stages, and has prepared both his own data and that of Hackfalls Arboretum in New Zealand for uploading to the database.

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The Morton Arboretum’s Oak Conservation Efforts in Mexico and Central America
Audrey Denvir, Murphy Westwood, Silvia Alvarez Clare

Mexico and Central America represent a global center of diversity for oaks with around 170 native species, but preliminary estimates suggest at least one-third of these are threatened with extinction. To address this problem, The Morton Arboretum established the Oaks of the Americas Conservation Network (OACN), and collaborates with local partners to spearhead a number of oak-focused conservation projects in this region. Two projects focus on particular species: Quercus brandegeei, a narrow endemic in Baja California Sur, and Quercus insignis, a widely distributed yet locally rare species. A third project focuses on building capacity and strengthening expert networks to advance our knowledge of taxonomy and distributions of rare Mexican oaks. These projects involve field work (demographic study, taxonomic survey, acorn collecting, etc.) and outreach (training workshops and educational materials). Our ultimate goal is to prevent oak species from going extinct. The outcomes of our efforts so far include the establishment of OACN, several successful species-focused conservation grants, improved scientific knowledge of poorly-understood species, and increased ex situ representation of some rare oaks. Our program can be used as a model for other species-focused conservation projects in Latin America or elsewhere in the world.

Silvia Alvarez Clare

Silvia is an ecosystem ecologist interested in studying how global change influences biological processes, plant functional traits, and biodiversity preservation. She has a Ph.D in Interdisciplinary Ecology from the University of Florida (UF), a M.S. in Botany also from UF and a B.S. in Biology from Universidad de Costa Rica in San José, Costa Rica. As part of her academic work Silvia uses long-term monitoring, manipulative experiments, and biogeochemical analyses to understand how environmental changes, such as changes in soil nutrients affect plant communities. As part of the Global Tree Conservation Program at the Morton Arboretum she develops conservation-focused research that aid in saving tree species from extinction. She also serves as an academic mentor for students at the Arboretum, is a guest researcher at Argonne National Laboratory, and is the co-leader of a local group that supports Women in Science.

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The ConServator – Conservation Mapping and its Role in Oak Conservation
Throughout the world, the traumatic effects of climate change are particularly evident on islands. The preservation of oak ecosystems requires that we can substantiate their value and advocate for their protection.  In 2013, the Polly Hill Arboretum developed a cloud-based mapping system using geographic information system (GIS) technologies with the goals of recording plant distributions, modeling climate change impacts, and the mapping of ancient oak forests. This collaborative with Harvard Forest, the Martha’s Vineyard Commission, and the land conservation organizations on Martha’s Vineyard has generated mapping tools that inform protection measures, protect biodiversity, and form the basis for oak preservation now and into the future.

Timothy M. Boland

Tim Boland is the Executive Director of the Polly Hill Arboretum on the island of Martha’s Vineyard, West Tisbury, Massachusetts, USA. Tim leads the Martha’s Vineyard floristic study group, a collaborative involved in documenting the flora of Martha’s Vineyard and the adjacent islands. Tim is a longtime member of the IOS and over the last decade has travelled on numerous seed expeditions in the US and abroad. As part of his ongoing work, he contributed to the recent Red List of US Oaks. His initial foray into oak conservation was as a graduate student at Michigan State University where he catalogued oaks as part of the Flora of Oaxaca. Tim has a MS Degree in botany and plant pathology from Michigan State University with a specialization in plant ecology and systematics. 

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Concurrent Session Track C: Insect and Pathogen Threats to Oaks

Oak Health Issues in the UK and Approaches to Ensuring Resilient Oak Trees for Future Generations 
This talk will contain two parts. Firstly, an overview of Acute Oak Decline (AOD) and status of the oak processionary moth in Britain will be given. Secondly, new research initiatives addressing protection and resilience of oak in the United Kingdom will be outlined. AOD, an emerging disease in the UK, is a serious threat to native British oaks in the Midlands and southern England and Wales. The disease is characterized by weeping stem lesions and larval galleries of the native bark-boring beetle Agrilus biguttatus. Decline-diseases are complex syndromes caused by multiple factors, beginning with tree predisposition, followed by impacts of biotic agents. The complex nature of the problem necessitates a holistic, multidisciplinary approach. A compact overview of research facets and achievements to date will be given. A brief update on the status of oak processionary moth in the UK will be presented. The UK government has launched its new Tree Health Resilience Strategy that aims to build resilience of trees, woods and forests to pests and diseases, and to improve and secure a long-term future of the nation’s trees. A key part of the oak resilience initiative is the “Action Oak Partnership,” a public-private partnership aiming to develop a nationwide oak monitoring scheme and multidisciplinary research program to safeguard oak tree health in the UK. Areas of research focus and oak tree health concerns will be explained.

Sandra Denman

Sandra Denman is a Project Leader and Senior Research Scientist with Forest Research in the United Kingdom. She obtained a PhD in Plant Pathology from the University of Stellenbosch, South Africa. She has extensive experience in soilborne and stem canker diseases. Her main interests are causes, effects and management of oak declines, where she uses a holistic research approach. Her specific interests are on the pathology and microbiological interactions in acute oak decline and chronic oak decline.

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Oak Mortality Patterns and Causes in the Midwest
Episodes of oak mortality, primarily associated with oak decline have been documented for at least 40 years in the lower Midwestern United States, particularly the Ozark Mountains physiographic region. In many ways, oak decline and mortality define the mid to late successional Quercus resource in that region and have contributed to successional development patterns. Trends associated with the latter half of the 20th century include dieback, decline, and mortality of Quercus, Sect. Lobatae (red oaks).   More recently, however, white oaks, section Lepidobalanus have experienced mortality in a rapid manner.  Etiology of decline and mortality between the two oak groups differs notably.  Periods of red oak decline and mortality have been associated with discrete events such as drought years, but site conditions, stand density, and forest age contribute to the observed decline and mortality events. Armillaria appears to be the most consistent biotic contributor to red oak decline and mortality but a notable eruptive population of a native xylophagous beetle, Enaphalodes rufulus likely accelerated oak mortality during the period 2000 – 2004.  Recent concern and investigation into white oak mortality reveals an absence of decline, per se, but abrupt mortality on otherwise vigorous individuals and forests.  Site characteristics, particularly topographic position, seems related to mortality. Phytophthora represents the most consistent biotic agent associated with white oak mortality.  Both dendrochronology and examination of recent mortality of white oaks suggest that periods of drought with intervening years of excess precipitation influence mortality events.

Rose-Marie Muzika

Rose-Marie Muzika is Professor Emerita at the University of Missouri. She is currently research associate at the Carnegie Museum of Natural History in Pittsburgh, PA. At the University of Missouri, she taught courses in Forest Ecology and Forest Health & Protection. Prior to working at the University of Missouri, she was research entomologist and research ecologist in Forest Service research in La Grande, OR and Morgantown, WV.

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Southern California Pest and Diseases: History, Biology and Current Research
Akif Eskalen, Shannon C. Lynch

Oak woodlands and riparian vegetation in southern California are some of the richest wildlife habitats in the state and serve as critical habitat for endangered species. The viability of these plant communities is threatened by two notable pests that have impacted the natural landscape over the last decade: invasive shot hole borers – Fusarium dieback (ISHB – FD), and goldspotted oak borer (GSOB, Agrilus auroguttatus). With over 280,000 native trees infested by ISHB – FB in the Tijuana River Valley alone and many acres of oak woodlands devastated by GSOB, these pests are a great concern to land managers, especially as many new infested sites continue to be identified throughout the region.
ISHB – FD is an emergent pest-disease complex formed by two ambrosia beetles (Euwallacea spp.), each associated with specific fungal symbionts. Since 2012, the number of reproductive host of the beetles has increased from 19 to 64, including 20 species native to California. The broad range of alternative hosts has fostered rapid spread from a single county in 2012 to seven counties throughout urban-wildland forests in 2018. Whereas ISHB – FD affects a broader range of hosts in riparian areas, GSOB has caused large-scale die-off of red oaks since its introduction from Arizona. A 2?year (2010–2011) assessment of the role of pathogens in Q. agrifolia woodlands where oak mortality occurs in locations that are infested by GSOB suggests that oak decline in California is an example of a complex syndrome involving strong regional differences in factors that are associated with the problem.

Akif Eskalen

Dr. Akif Eskalen is a Plant Pathologist and Cooperative Extension Specialist in the Department of Plant Pathology at the University of California, Davis since Sept 2018. He received a M.Sc. and a Ph.D. in Mycology and Plant Pathology from the University Cukurova in Turkey, his country of origin. Dr. Eskalen moved to the USA for post-doctoral research and then project scientist at the Department of Plant Pathology at UC Davis and then CE specialist at the Department of Microbiology and Plant Pathology at UC Riverside.Dr. Eskalen’s primary research interests include the biology, detection, epidemiology and control of fungal pathogens including new potential threats, and addresses how these pathogens interact to contribute to plant decline. 

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Sudden Oak Death: Trends and New Discoveries
David Rizzo, Susan Frankel

Sudden oak death, caused by Phytophthora ramorum, is a devastating plant disease first detected in coastal oak forests of California in the mid-1990s. Evidence strongly suggests that P. ramorum was introduced into California, Oregon, and Europe via ornamental nursery plants. Over the past 20 years, millions of oaks (Quercus spp.) and tanoak (Notholithocarpus densiflorus) have died in California and Oregon with significant ecological, social, and economic impacts. The pathogen continues to spread in coastal forests from Monterey County into southern Oregon. Above-average precipitation in 2016-2017 has led to a recent surge in tree mortality. The prevalence of standing dead trees is causing concern over fire risk as similar areas in California experienced devastating fires in 2008, 2013, 2016, and 2017.  A European lineage of the pathogen was detected in Oregon during 2017-2018 in eight areas clustered in Curry County. Eradication of these infestations is being attempted by herbicide application, cutting, piling, and burning. In addition to P. ramorum, other Phytophthora species have been detected in coastal plant communities and appear to have been inadvertently introduced into Bay Area restoration sites. This includes threatened and endangered species habitat.  These new detections are raising concerns that nursery stock movement remains a significant pathway for invasive species that threaten the health of urban and wildland trees as well as habitat for sensitive species. 

David Rizzo

David Rizzo is professor and Chair in the Department of Plant Pathology at UC Davis. His research focuses on the ecology and management of diseases of forest trees. These diseases include those caused by introduced pathogens as well as native pathogens. Research in the lab takes a multiscale approach ranging from experimental studies on the basic biology of organisms to field studies at landscape scales. Sudden oak death has been a major focus of research over the past 18 years. 

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