Program for October 23

Image of the Peter J. Shields Oak Grove in the UC Davis Arboretum.

Tuesday, October 23

8 - 10 a.m.                                       

Concurrent Sessions

 

 

Track A: Oak Evolution and Genetic Diversity

 

 

Functional Diversification in the 'Roburoid Oaks' 
Link to abstract  

José A. Ramírez-Valiente et al.
Centre of Forest Research
INIA-CIFOR, Madrid, Spain

 

Ecosystem Consequences of Species Coexistence in Highly Diverse Oak Communities
Link to abstract
Antonio González-Rodríguez
Universidad Nacional Autónoma de México
  Population Genetic Structure of Bur Oak 
Link to abstract
Mira Garner
The Morton Arboretum
  Episodic Hybrid Advantage Keeps Species Boundaries Low in Oaks
Link to abstract
Warren Chatwin
University of Notre Dame
 

Track B: Oak Land Management and Conservation Concerns

 
  Reforestation of Mount Tavor Oak in Low Land of Israel
Link to abstract
Ezra Barnea
Barnea Oak Nursery
  Oak Woodland Regeneration in Fuel Treatment Areas Before and After the 2017 Tubbs Fire, Sonoma County, CA 
Link to abstract
Michelle Halbur et al.
Pepperwood Preserve
  Biotic and Abiotic Factors and Their Involvement in Oak Trees Decline and Mortality Phenomenon in Northern Israel
Link to abstract
Idan Kopler
Shamir Research Institute 
University of Haifa, Kazrin, Israel
  Drought and Beetle Impacts to Native Trees in the Santa Monica Mountains: What Does the Future Hold? 
Link to abstract
Rosi Dagit
Resource Conservation District of the Santa Monica Mountains
10 - 10:20 a.m.                                 

Coffee Break

 
10:20 a.m. - 12 p.m.                                                                            

Concurrent Sessions

 
 

Track A: California Oak Evolution and Genetic Diversity 

 
  Potential Role of Epigenetics in Ability of Oaks to Respond to Environmental Change 
Link to abstract
Victoria Sork
University of California, Los Angeles
  Modeling Adaptive Gene Flow in California White Oaks Through Historic and Future Climate Change
Link to abstract
Prahlada Papper
University of California, Berkeley
  Evolution and Diversification of California Red Oaks
Link to abstract
Paul Manos
Duke University
  Disentangling the Phylogenetic Network of the California Red Oak Clade 
Link to abstract
Richard Dodd
University of California, Berkeley
 

Track B: Horticulture

 
 

Managing Oak Wilt
Link to abstract

Guy Sternberg
Starhill Forest Arboretum
  Micropropagation of the Rare Ring-cupped Oak
Link to abstract
Qiansheng Li
Shanghai Institute of Technology
  Southwestern US Oaks: An Ornamental Propagation Nursery's Effort to Make Superior Ornamental Selections Available for Commercial and Public Planting
Link to abstract
Mark Krautmann
Heritage Seedlings & Liners
  Evaluation of Evergreen Oaks for Southeastern Landscape
Link to abstract
Mark Weathington
JC Raulston Arboretum at North Carolina State University
12 - 1 p.m.                                 

Lunch Break

 
1 - 4:30 p.m.                                     

Local Tours

 
 

The following bus, walking and bicycling tour options will be offered.
Link to tour descriptions

  • Capitol City Tree Tour
  • City and Campus Notable Oaks Bike Tour
  • Putah Creek Oak Restoration and Regeneration Tour
  • UC Davis Plant Conservation and Curation Tour
  • UC Davis GATEways Project Tour
  • UC Davis Arboretum Collections Tour
  • Shields Oak Grove Deep Immersion Tour 
 
5:30 p.m.                                 

Buses depart for Sacramento

 
6 - 9 p.m.                                  

Gala Dinner, Awards Ceremony
and Keynote Address

 

 

More about the Keynote Address

Historical Ecology of Northern California: Learning from the Past to Prepare for the Future
Link to description

Robin Grossinger
San Francisco Estuary Institute

Concurrent Session Track A: Oak Evolution and Genetic Diversity

José Ramirez, Ismael Aranda, Rosana López

Functional Diversification in the ‘Roburoid Oaks’
Disentangling how species diverge is one of the main research questions in evolutionary ecology. Speciation events have been associated with geographic isolation, environmental adaptation or a combination of both. In this study, we tested for differences in functional traits among species of the so-called 'roburoid' oaks. 'Roburoid oak complex' is a set of nine closely related species (Quercus robur, Q. petraea, Q. canariensis, Q. pubescens, Q. faginea, Q. fruticosa, Q. pyrenaica, Q. macranthera and Q. infectoria) distributed in western Eurasia and northern Africa that belong to section Quercus of the genus (white oaks). These species are characterized by different growth forms (shrubs, small trees, tall trees), leaf habits (deciduous, marcescent, semi-evergreen, evergreen), ecological niches and distribution ranges. Different evolutionary factors such as vicariance, ecological adaptation and hybridization have been proposed as the main mechanisms shaping patterns of diversification among these species. In this study, we grew seven species of the 'roburoid' complex that inhabit in the Iberian Peninsula (all species except for Q. macranthera and Q. infectoria) under two watering treatments. Our preliminary results showed high inter-specific differentiation in growth rates but also high differences among species in most traits associated with leaf morphology, phenology and physiology. Counterintuitively, growth rates were not necessary associated with leaf habit, leaf thickness and specific leaf area. In fact, growth form rather than growth rate explained differences in climatic niches among species. Overall, our results suggested a high functional differentiation within this group of closely-related species associated with the adaptation to different climatic regimes.

José A. Ramírez-Valiente

José obtained his PhD in 2010 at the Technical University of Madrid, Spain on Forest Ecology and Genetics. After that, he worked as a postdoctoral research fellow in several institutions worldwide including Australian National University, University of Minnesota and the Spanish Research Council. His research focused on evolutionary biology and is broadly interested in questions related to the study of the processes that shape patterns of functional divergence and genetic differentiation at different organizational levels. He has developed most of his work using oaks as model systems, taking a multidisciplinary approach to his research by combining techniques from different fields such as ecophysiology, quantitative genetics and genomics.

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Ecosystem Consequences of Species Coexistence in Highly Diverse Oak Communities
Quercus species are among the most important elements of forests in the Northern Hemisphere. In particular, Mexico is a major center of richness and endemism for oaks, with two main sections, Lobatae (red oaks) and Quercus (white oaks), having experienced a rapid and parallel diversification in this region. Considering this high diversity, in this study we asked: i. What is the degree of oak species coexistence at local scales in forest communities of Central Mexico? ii. What are the consequences of the variation in local oak species diversity and composition for soil nutrient cycling and microbial diversity? To answer these questions, we characterized local tree species diversity and composition in 22 oak forests and collected samples of soil and litter to quantify the concentration of carbon, nitrogen and phosphorous in their different forms (total, available, dissolved and microbial) and the activity of three enzymes involved in the decomposition of organic compounds. The soil bacterial community was analyzed through metabarcoding using sequences of the 16 S ribosomal gene. We found that between one and eight oak species may be present at the stand level in the forests studied. Interestingly, not richness, but the relative proportion of white versus red oak species showed the strongest associations with nutrient dynamics and bacterial community structure. These effects may be explained by differential physiological processes in the efficiency of foliar nutrient resorption between the two oak sections. Overall, these results contribute to the understanding of oak community assembly and the importance of the ecosystem services they provide.

Antonio González-Rodríguez

Antonio was born in Mexico City. He graduated as a biologist and received his Ph.D. in Ecology from the National Autonomous University of Mexico (UNAM). As a postdoc, he visited the Institut Nationale de la Recherche Agronomique (INRA) in Bordeaux, France, and the Department of Ecology, Evolution and Behavior, University of Minnesota, United States. He currently works as a full-time researcher at the Institute of Research in Ecosystems and Sustainability at UNAM in Morelia, Mexico. His main research topics are the evolution and conservation of oaks and other temperate tree lineages in the Neotropics.

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Population Genetic Structure of Bur Oak (Quercus macrocarpa)
The charismatic and widespread Eastern North American bur oak, Quercus macrocarpa, is an ideal species for studying hybridization. Like most oaks, bur oak exhibits strong morphological and ecological species coherence, but it hybridizes readily with at least eight currently or historically sympatric oaks species throughout its range. It ranges in habitat from bottomland forest to grasslands with frequent historical fire regimes, from Texas north to Manitoba, and from Michigan west across the Great Plains. Its geographic and ecological variation thus makes bur oak a good candidate to address the question of how hybridization and gene flow might affect adaptation to regional environmental stresses and climate change. Moreover, genetic diversity in Q. macrocarpa is high and populations within a geographic region display relatively low differentiation. Little is known about landscape-level genetic variation in the species and patterns of hybridization across its range. Our study investigates (1) population genetic structure of Q. macrocarpa and (2) genetic coherence of the species throughout its range, as it comes into contact with 5 widespread co-occurring white oak species whose ranges all overlap a subset of the range of Q. macrocarpa. We sampled more than 50 populations of bur oak and representatives of all white oaks found at each site where we collected bur oak. In this presentation, we present data generated using a novel panel of ca. 320 genes sequenced using sequence-capture methods (HybSeq), including roughly 100 genes associated with either drought- or cold-tolerance.

Mira Garner

Mira Garner is a research assistant in the Plant Systematics lab at the Morton Arboretum. Mira earned her undergraduate degree at the University of Minnesota - Twin Cities studying ecology and evolution. After graduating, she began work at the Morton Arboretum on an experiment investigating the effects of phylogenetic diversity on prairie restorations. In March 2017, she transitioned to her current role studying the population genetics of bur oaks (Quercus macrocarpa). Mira is interested in the intersection of ecology and evolution. Specifically, she wants to address questions related to the evolution of a species to fit its ecological niche and  local adaptation across its range.

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Episodic Hybrid Advantage Keeps Species Boundaries Low in Oaks (Quercus)
Permeable species boundaries are common within the order Fagales suggesting that interspecific hybridization has adaptive value. We hypothesize that some hybrid individuals have novel allelic combinations that may enable survival during severe abiotic stress. We also propose that this effect is strongest during the long juvenile period of the life cycle. Our studied species pairs are the sympatric Quercus macrocarpa-Q. bicolor and the allopatric Q. robur-Q. bicolor. Hybrids were the naturally pollinated progeny of Q.×warei (Q. robur × Q. bicolor) and Q. × schuettei (Q. bicolor × Q. macrocarpa). At age two, 500 parentage-known progeny of each hybrid type and 80-100 seedlings of each parent species were moved into a greenhouse. Half of the seedlings were subjected to four consecutive weeks of intense drought while the other half were well watered. Two leaves per individual were saved for sequencing. Survival rates in the controls were 100%. For drought-stressed trees, apparent survival rates were 13% for Q. bicolor, 13% for Q. robur, 20% for Q. macrocarpa, 16% for progeny of Q. × schuettei and 33% for progeny of Q. × warei. Surviving progeny from both hybrids had a wide range of leaf counts and heights. We preliminarily conclude that some hybrids do as well as or better than their parental species under drought stress and their survival may be the result of many different genetic combinations. Statistical analysis of the phenotypic data is in progress and reduced representation sequencing of all parents and hybrids is planned.

Warren Chatwin

Warren Chatwin is a PhD Candidate at the University of Notre Dame, under Dr. Jeanne Romero-Severson, and studies the evolution of hybridization in oaks (Quercus). Specifically, he studies whether intense abiotic stress events (such as drought) have limited the formation of reproductive species boundaries in oaks. In his PhD research, he tests whether short intense periods of drought have favored the survival of some hybrid oak seedlings due to novel allelic combinations that rarely exist in the parental species. Simply by surviving a major stress event, these hybrid seedlings would have increased access to resources that boost their likelihood of reaching maturity and locally suppressing the formation of species boundaries. This local effect, occurring wherever oaks are sympatric, would result in the global within-section compatibility we currently observe among oaks. After his PhD, Warren plans to seek a post-doctoral research position to continue to study forest tree evolution. 

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Concurrent Session Track B: Oak Land Management and Conservation Concerns

Reforestation of Mount Tavor Oak in the Low Land of Israel
The Mount Tavor oak, Quercus ithaburensis, is a magnificent mid-size tree. This oak dominated the lowlands of Israel between Tel Aviv and the Galilee in a thick forest up until the 18th century. Over the last 200 years, intensive human activity cleared most of this forest, leaving rare territories and spots of these trees for mankind to value. Climate change and decreases in rainfall are adding pressure on the remaining forest. The Israeli National Forest (INF) division, in a major project of reforestation, planted 240 million trees over a period of 110 years, covering 10% of the populated land. The majority of those trees are Pinus halepensis. Reforestation of pines introduces shade and promotes the recovery of fauna and flora. At the same time, pine forests are highly flammable; taking high tolls on neighboring communities. Many stakeholders understand that pine forests should be shifted gradually back to natural oak forests, returning to their natural status and habitat. Achieving this goal of reforestation requires education of decision makers, the public and the planting and sowing of Tavor oaks in the lowlands of both public and private landscapes. Like growing an oak tree 15-25 year from acorn to a ready-made tree in a nursery, this is a long-term project. It will make a better fit between Israeli communities and nature, it will decrease the risk of fire, and it will better fit the new/old forests to the warming and drying environment.

Ezra Barnea

Ezra Barnea earned a B.Sc. in Geology from the Hebrew University and an M.A. in Education from Haifa University. A self-taught oak grower and collector, Barnea is passionate about oak trees. He founded "Barnea Oak Nursery" in 1992 that spans 6000 square meters. Barnea planted his first trees in 1986, and a larger section in 1992, a short time after his fourth son, Alon (Hebrew for ‘oak’), was born. His oak collection includes over 80 species from all major oak territories. Barnea is active in running annual seminars and lectures and consulting with private and professional tree growers. He manages an extensive website and Facebook group dedicated to oak trees.

Barnea's current oak initiative is the Israeli Oak Registry - IOR. The aim of the IOR is to identify, measure, and register the location of all oak trees in Israel, wild or planted, that have a diameter of 50 cm or more.

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Oak Woodland Regeneration in Fuel Treatment Areas Before and After the 2017 Tubbs Fire, Sonoma County, CA
Michelle Halbur, Sasha Berleman, Michael Gillogly, David Ackerly, Tosha Comendant

Multiple oak species in California have evolved to withstand fire disturbance through their association with the Mediterranean climate and Native American peoples. Future climate models forecast increased fire frequency in the North Coast region of California. Combined with fire suppression, and increasing fuel loads and fire severity, the resiliency of coastal oak forests to future wildfires is not well understood. In October 2017, the Tubbs Fire burned through Pepperwood Preserve. Prior to this disturbance, multiple regions were treated for Douglas-fir encroachment including long-term forest monitoring plots and a combined 18 acres of black oak, coast live oak, and mixed oak forest slated for a prescribed burn. In the prescribed burn area a modified Brown's plot design was used to sample approximately 10% of the management area for pre- and post-fire effects on the herbaceous understory community, tree canopy cover, seedling recruitment, and fuels. After the 2017 Tubbs Fire, about 66% of all trees (N=100) exhibited full canopy leaf scorch and another 13% (N=20) had no leaves due to full canopy consumption. We also detected a substantial decrease in fuels and the number of tree seedlings. Given an 80% reduction in the litter/duff layer, future oak seedling recruitment may be enhanced by the direct contact of acorns to soil. During 2018 surveys we will document mortality, regeneration and recruitment in all fuel treatment plots. Through long-term monitoring of fuel treatments and interactions with wildfire in this region, we will contribute to a growing knowledge of factors impacting oak forest resiliency.

Michelle Halbur

Michelle Halbur has an M.S. from Purdue University where she studied the conservation genetics and ecology of a rare vernal pool plant that occurs in California's Santa Rosa Plain, Sebastopol meadowfoam. Since 2011, Michelle has served as Pepperwood’s Preserve Ecologist where she oversees Pepperwood’s Citizen Science and Visiting Scholars programming. She manages the majority of on-site research projects including the Wildlife Picture Index, grassland and forest monitoring, prescribed fire monitoring, plant phenology, breeding bird surveys, the Stephen J. Barnhart Herbarium, and more. Michelle also helps to translate Pepperwood’s conservation science for a variety of audiences, including students, interns, and the public.

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Biotic and Abiotic Factors and Their Involvement in Oak Trees Decline and Mortality Phenomenon in Northern Israel
Forest tree decline has been reported worldwide and in Israel and is related to regional and global climate change. Oak (Quercus spp.) decline in Israel has been documented in the Jerusalem Mountains, the Galilee, the Carmel, and Southern Golan Heights. Interaction of biotic and abiotic stress factors such as summer drought water stress may expose trees to damaging biotic agents such as pathogenic fungi. Our research goal was to characterize the health status of oak populations in Golan and Hermon under regional stress factors in four plots through stand structure survey, monitoring water regime, and initial screening of xylem fungi from Botryosphaeriaceae family in oaks of varying declining stages. 1158 oaks were sampled to examine declining rates during 2016-2017. Negligible measures of decline and a lack of tree mortality were observed in Hermon and Northern Golan. Total canopy loss of 20% and high measures of Q. ithaburensis mortality were recorded in Central and Southern Golan populations. Stem water potential values were significantly lower in declined trees, though only at regional scales.  Eight fungi species from the Botryosphaeriaceae family and Biscogniauxia mediterranea from Xylariaceae family were identified in oaks of varying declining stages. Significant correlation between leaf density and fungal presence were found only in the most southern plot. We conclude that tree decline are species, soil and morphology-dependent. Among the three Quercus species in the Golan Heights, Q. callipronos is not affected and Q. ithaburensis is most affected. Pointing to actual causes is difficult at this stage.

Idan Kopler

Since his M.A., Idan Kopler has been interested and focused on the complex ecosystems of Northern Israel. While his M.A. thesis concentrated on repercussions of anthropogenic-induced fragmentation processes, his Ph.D. dissertation and current Post-Doc research focuses on the forest ecosystems in the Golan Heights. Particularly, his studies investigate the water cycles in forest stands and their response to emerging and on-going environmental processes such as climate change and its derived phenomenon such as forest decline and tree mortality. He has a growing interest in the field of forest pathology, and its connection to ecological processes. He implements advanced field-based methods and laboratory work along with state of the art statistical analyses to investigate his field of interest. 

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Drought and Beetle Impacts to Native Trees in the Santa Monica Mountains: What Does the Future Hold?
Since 2014, hundreds of native trees (alders, oaks, sycamores, willows) in the Santa Monica Mountains have died, mostly due to the drought, but many are also victims of the polyphagous shot hole borer/fusarium complex (PSHB) and a new pathogen carried by the western oak bark beetle (WOBB). Concerned about the ecological implications of massive native tree loss, the Resource Conservation District of the Santa Monica Mountains (RCDSMM) initiated a citizen science based study of drought impacts in 2015 using 41 randomly selected, 25 meter plots, tagging over 350 trees in critical park areas near the urban wildland interface, throughout the western Santa Monica Mountains National Recreation Area. This effort was augmented in 2017 by the deployment of 46 homemade beetle traps in sensitive riparian areas to monitor direction and rates of spread of invasive beetles and document tree responses. Concurrently, this data provided on-the-ground information used in a NASA DEVELOP Project using remote sensing tools and satellite data to help understand the landscape level impacts over time. Results show that extensive drought impacts occurred in 2015, followed by increased loss associated with invasive pathogens in 2016-17. To date, infected tree removal is the only recommended way to reduce impacts from amplifying host trees. The RCDSMM is working with regional and local parkland managers and other concerned stakeholders to develop a more appropriate and realistic management strategy for urban/wildland interface trees to meet the forecast challenges of a changing climate. 

Rosi Dagit

Since 1988, Rosi Dagit has been involved in various aspects of oak woodland ecology and resource management in the Santa Monica Mountains. Her interest in woodlands as a major influence on watershed stability led to an in-depth study of the effectiveness of oak protection ordinances in preserving oak woodlands in Los Angelos County.  She conducted a long-term study of transplant survival that looked at physiological responses of oak trees, in addition to the usual visual assessments. Rosi coordinated the Los Angeles County Oak Woodlands Conservation Management Plan adopted in 2011.  Her recent coordination of early detection-rapid response citizen science volunteers and collaboration with the NASA DEVELOP program resulted in a road map for responding to the impacts of drought and invasive beetles in the Santa Monica Mountains.

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Track A: California Oak Evolution and Genetic Diversity

Potential Role of Epigenetics in Ability of Oaks to Respond to Environmental Change
Victoria L Sork, Sorel Fitz-Gibbon, Luke Browne, Jessica W. Wright, Matteo Pellegrini

Epigenetics is the study of heritable phenotypic variation that does not involve changes in the DNA sequence. Epigenetic processes may be particularly relevant to long-lived tree species, such as oaks, as a mechanism to rapidly respond to environmental change when evolution may not keep pace. One such mechanism involves DNA methylation, where methyl groups are attached to specific cytosines (Cs) in the DNA sequence, creating phenotypic changes by regulating gene expression, silencing transposons and repetitive sequences, or shaping cell differentiation. DNA methylation can also influence phenotypic response to the environment through non-epigenetic mechanisms when the environment triggers methylation. Such methylation may be one of the mechanisms underlying phenotypic plasticity. In the first part this talk is to summarize what is known about the role of DNA-methylation in oaks and other tree species. In the second part, we will present studies of Quercus lobata in our lab on the following topics: (i) associations of DNA methylation patterns and climate gradients in adults sampled from natural populations throughout California; (ii) analysis of parent-offspring correlation DNA-methylation as evidence of heritable DNA methylation; (iii) testing whether DNA methylation can be environmentally induced; and (iv) evaluating the extent to which DNA methylation shapes gene expression. We will end with a discussion of the potential role of epigenetics in oaks to shape adaptive phenotypic response to rapid environmental change.

Victoria Sork, University of California, Los Angeles

Victoria Sork was appointed Dean of Life Sciences in the UCLA College of Letters and Science in 2009. From 2004 to 2009 Professor Sork chaired UCLA’s Department of Ecology and Evolutionary Biology, where she has been on faculty in this department and the Institute of the Environment and Sustainability since 2002. Elected in 2004 as a fellow of the American Association for the Advancement of Science, she has conducted pioneering research in the field of landscape genomics, which integrates genomics, evolutionary biology and conservation science. She is particularly concerned with the ecological and genetic processes that will determine whether California oaks will tolerate climate change.

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Modeling Adaptive Gene Flow in California White Oaks Through Historic and Future Climate Change
The maintenance of reproductive compatibility within taxonomic sections of the genus Quercus despite long evolutionary divergence supports Van Valen's theory of a multispecies evolutionary unit. Van Valen suggested that gene flow could be adaptive across ecological gradients for a hybridizing multispecies complex. We tested this idea in three hybridizing California white oaks: Quercus douglasii, Q. garryana, and Q. john-tuckeri. By combining population-level genomics with ecological models and phenological observation, we show that the genetic differentiation in this group falls out along climate gradients rather than geographic distance and also suggest that this pattern is mediated by flowering time and pollen flow. This mechanism results in a novel adaptation to climate change in oaks; as between site climate connections shift and decouple under a changing regional climate, patterns of gene flow among populations will follow along. We develop a model that predicts 85% of the variation in bud break across 45 populations of the three target oak species and use this model to predict flowering synchrony across four distinct historical and future climates: the last glacial maximum (21 kya), the Holocene climate optimum (6 kya), the 20th century climate baseline (1951-1980), and a high atmospheric forcing climate future (RCP 8.5 CCSM4 for 2070-2099).

Prahlada Papper

Prahlada Papper is a doctoral candidate in Integrative Biology at UC Berkeley in the Ackerly lab group. His research focuses on the evolution and ecology of California oaks and oak woodlands, combining genomic methods with ecological models and deep natural history.

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Evolution and Diversification of California Red Oaks
Paul Manos, Al Keuter

We investigated the evolutionary history and taxonomic status of the red oaks (Lobatae, Agrifoliae) of the California Floristic Province (CA-FP) using RAD-seq data and morphometric data. Nuclear DNA sequences from wild-collected plant material representing four species across their ranges, including varieties and hybrids were analyzed phylogenetically, and divergence times were estimated. We also assessed species delimitation and admixture in key locations.  We find that the Agrifoliae are monophyletic and sister to all other red oak species. Within the Agrifoliae, all species are supported, with Q. kelloggii sister to a clade of subevergreen taxa: (Quercus agrifolia – (Q. parvula + Q. wislizeni)). Molecular and morphometric analyses are equivocal for named varieties. Notably, Q. parvula var. tamalpaisensis appears to be part of a hybrid swarm between Q. parvula and Q. wislizeni. Dating estimates were concordant with previous hypotheses and geological evidence, with diversification occurring between 10 and 20 MYA. The Agrifoliae represent a geographically discrete, early-diverging red oak lineage that diversified during the period of drying and warming associated with Sierran uplift during the middle Miocene. Molecular differentiation within the subevergreen clade supports the current taxonomy, including an East/West species level pattern (Q. parvula and Q. wislizeni) and North/South intraspecific patterns, although the latter require additional study.

Paul Manos

Paul Manos is the Jack H. Neely Professor and Chair of Biology at Duke University. He studies the phylogenetics and biogeography of flowering plants, with focus on forest trees, in particular the oak and walnut families and their relatives. He received his master's degree from Rutgers University for genetic work on the red oaks of the eastern U.S. and later investigated the molecular systematics of Quercus and Fagaceae for his doctorate at Cornell University.

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Disentangling the Phylogenetic Network of the California Red Oak Clade (Quercus, section Lobatae, series Agrifoliae)
Richard Dodd, Prahlada Papper

Delimiting species boundaries and evolutionary history in the California red oak clade remains difficult, likely as a result of extensive multispecies hybridization and complex biogeographic patterns. Even recent genomic analyses have not fully clarified relationships and monophyly in the clade. Here we report on new analyses that combine genomic sequencing methods with range wide population-level sampling for all species in the California red oak clade. We find that traditional phylogenetic tree methods are not suitable at this taxonomic scale. Instead we explore phylogenetic network methods together with clustering on inferred gene trees as potentially more appropriate to the evolutionary history of the group. The California black oak (Quercus kelloggii) and coast live oak (Q. agrifolia) are shown to be largely distinct lineages while relationships among interior live oak (Q. wislizeni), shreve oak (Q. parvula var. shrevei), and island oak (Q. parvula var. parvula) indicate a multispecies complex with geographic and ecological structure.

Richard Dodd

Richard Dodd is professor in Environmental Science, Policy, and Management at University of California, Berkeley. His research uses molecular methods to investigate the evolutionary dynamics of populations of species and species complexes in response to past and future environmental change. In oaks, he has focused on the role of hybrid events in colonization particularly under past and future climate change and the response of hybrids to pests and diseases.

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Concurrent Session Track B: Horticulture

Managing Oak Wilt
Oak wilt disease (Ceratocystis fagacearum) is a systemic fungus transmitted by multiple methods. It is fatal to most - if not all - oak taxa that are infected, and it is becoming increasingly prevalent in the eastern and central United States. Long thought to be an endemic disease, new observations suggest that it might have been introduced decades ago, perhaps from Central America. Oak wilt disease could be considered the most serious oak pathogen due to its broad and expanding range, its consistently fatal results, and the number of species susceptible. The Plant Collection Network oak collection at Starhill Forest Arboretum in Illinois has dealt successfully with this problem on two occasions, with some trees being killed each time before eradication has been completed. The arboretum first observed the putatively successful fungus transmission via root grafts across three taxonomic sections (published on the International Oak Society website), making control of this disease problematic even in genetically diverse oak groves or intersectional groupings such as arboreta. Treatment practice includes trenching, injection, tree removal, stump treatment, and follow-up observation, with critical timing and application protocols being followed. 

Guy Sternberg

Sternberg is the founding president of the International Oak Society. He and his wife Edie established Starhill Forest Arboretum in 1976. During the ensuing four decades, the arboretum has grown into the most comprehensive Plant Collection Network-certified living collection for Quercus in the American Public Garden Association system. Oak wilt disease is epidemic in the surrounding area, and Sternberg has found and developed methods for controlling this problem. 

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Micropropagation of the Rare Ring-cupped Oak, Quercus arbutifolia
Qiansheng Li, Min Deng

Quercus arbutifolia, native to montane cloud forests of subtropical China and southern Vietnam, is currently listed as Vulnerable by the International Union for Conservation of Nature (IUCN) Red List, and its endangered status may in fact be worse due to low acorn production. The main objective of this work is to optimize the reproducible micropropagation protocol for mass multiplication of this species. Micropropagation has become a reliable and routine approach for large-scale rapid plant multiplication, and as such, the technique is of key importance for ex-situ conservation efforts. The project will evaluate different tissue culture media and growth media for the different stages of the micropropagation process (shoot regeneration, shoot proliferation, rooting and acclimatization) and will aim to standardize the protocols and procedures involved.

Qiansheng Li

Qiansheng Li obtained a PhD in Horticulture (focus on greenhouse horticulture and hydroponics) in July, 2003 from Nanjing Agricultural University, China. Li worked as Post-doctor/research associate at Department of Environmental Horticulture, Mid-Florida Research and Education Center, University of Florida, USA from Jan 2006 to May 2009. Currently Li is working at Shanghai Institute of Technology as an associate professor, Shanghai, China. Current research works are focusing on the collection, propagation and cultivation of oaks.

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Southwestern US Oaks: An Ornamental Propagation Nursery's Effort to Make Superior Ornamental Selections Available for Commercial and Public Planting
Oaks of the United States Southwest are exceptional for their diversity of species and complex inter-specific hybrids. Heritage Seedlings has been collaborating with Allen Taylor, an expert in the oak flora of Colorado, New Mexico, Arizona and extreme western Oklahoma, to select wild oaks for their ornamental appeal. A few additional selections come from Oregon and California. Many are of the Quercus × undulata complex, with obvious cross-overs into Q. gambelli, Q.havardii, Q. grisea and Q.  turbinella. These beautiful selections are drought, heat, and high pH tolerant, with ornamental features including bluish foliage, shrubby to tree-like habit, and ability to grow well in a commercial nursery. Grafting is accomplished by the hot callus method onto Q. macrocarpa of a hardy, high pH-tolerant North Dakota source. Initial results are most promising. We have identified about 15 clearly distinctive, superior forms from among more than four times this number of initial trial taxa. Allen has put tens of thousands of miles on his pickup scouring remote roadsides to make these selections for many years. Clearly he's a candidate for OAK MANIAC of the generation award! We feel blessed to work with him, with our first releases going to Devil Mountain Nursery in the SF Bay area of California and to Blue Heron Nursery in Salem, Oregon. Trademarked under the name SOUTHWEST OAKS, we aim to continuously evaluate our successes, improve production and distribution, and make these wonderful American wild plants part of the constructed landscape in the American West.

Mark Krautmann

After growing up on a farm in Missouri, Mark Krautmann completed an MS degree at Texas A&M in soil microbiology.  He and Jolly, his spouse of 41 years, moved to Oregon and started Heritage Seedlings 37 years ago. They are each actively involved in all aspects of its management. Together, Mark and Jolly have dedicated their nursery staff and resources to extensive wildlife habitat restoration, including more than 200 acres of Oregon oak (Q. garryana) savanna and woodland habitat on their farms. Recipients of numerous awards for resource stewardship, they grow a wide scope of native plants, including rare/threatened species in cooperation with various agencies and nonprofits. Mark and Jolly continue to refine and improve their line of unusual ornamental tree and shrub liners, with a special focus on native oaks, especially those that offer features of drought, high pH an extreme heat tolerance in this period of rapid climate change.

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Evaluation of Evergreen Oaks for Southeastern Landscapes
The urban forest increasingly needs to perform multiple functions: provide shade and cooling, reduce runoff, and provide habitat for birds and arthropods, amongst others. Oaks (Quercus) have long been favored trees of the southeast, but the evergreen species from Asia and Mexico have been mostly ignored. The JC Raulston Arboretum has been evaluating many species for their suitability to the Southeastern landscape.

Mark Weathington

Mark Weathington is director of the JC Raulston Arboretum where he has worked for over a decade.  Previous positions have included Director of Horticulture for the Norfolk Botanical Garden and Horticulturist for the Atlanta Botanical Garden. Mark has recently published Gardening in the South through Timber Press.

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Local Tour Descriptions
 

Capitol City Tree Tour of Sacramento
Experience the beautiful oaks of Sacramento and take a guided tour of Capitol Park, the grounds around the state capitol. The first part of the tour will highlight the history of our native oaks and how they have been incorporated into the modern urban forest of the Capitol City. For the second half of the tour, we will visit Capitol Park which covers 12 downtown city blocks and was first planted in 1869.  It contains 11 State Champion trees and 5 National Champion trees including the National Champion holly oak (Quercus ilex) tree. After this tour, we will travel directly to the gala dinner being held nearby. Zarah Wyly, Restoration Ecologist with the Sacramento Tree Foundation and intrepid acorn collector, will lead the tour.

City and Campus Notable Oaks Bike Tour
What better way to experience the International Oak Society Conference in Bike City USA than with a Notable Oaks Bike Tour! Grab a bike (bring your own, or sign up for a rental), and join local urban forestry experts and bike enthusiasts Julia Jones (City of Davis), Yael Franco (Tree Davis), and Melanie Gentles (UC Davis) for a 12-mile loop around the City of Davis and UC Davis Campus. The tour will make 15 stops that highlight this city's oak diversity, heritage tree preservation, oak-inspired art, and general love for Quercus. The tour will start with a walk to the UC Davis Bike Barn and end at Shields Oak Grove.

NOTE: Participants should be physically capable of biking 12 miles on flat terrain. Bring your own water bottle (refillable along the bike route). Helmets required and available for rent to those who need them.

Putah Creek Oak Restoration and Regeneration Tour
Visit Putah Creek, which flows through the UC Davis campus, and learn about the unique campus-community-government partnerships that have contributed to the restoration of this once-imperiled ecosystem. JP Marie, Manager of the UC Davis Putah Creek Riparian Reserve, will lead a tour to look at oak regeneration on the restored native grasslands at Russell Ranch, an area that was set aside as habitat mitigation for Swainson's Hawk, Burrowing Owl, and Valley Elderberry Longhorn Beetle (VELB). Further upstream, the group will visit a restoration site in Winters that has been recently planted by community volunteers coordinated by Putah Creek Council. The tour will end in Peter J. Shields Oak Grove to explore the diverse tree collection as well as habitat enhancement projects that have happened in the grove and the nearby historic creek channel.

UC Davis Plant Conservation and Curation Tour
Join this tour to visit on-campus sites at UC Davis where work is underway to advance plant conservation measures worldwide. We will make stops at the UC Davis Center for Plant Diversity to visit the herbarium’s large holdings of Quercus specimens, walk through the UC Davis Arboretum’s gardens that celebrate local biodiversity, and see wild-collected Quercus species that are grown for research and teaching collections. The tour will conclude at Peter J. Shields Oak Grove, one of the largest and most diverse oak collections in the country, focusing on trees from the southwest U.S., Mexico, and the Mediterranean region. UC Davis Arboretum and Public Garden staff Shannon Still (Director of Plant Conservation and Curator), Mary Burke (Director of Conservation and Environmental Leadership), and Rachel Davis (GATEways Horticulturist) will be your guides.

UC Davis GATEways Project Tour
The UC Davis GATEways Project (Gardens, Arts, and The Environment) is a major initiative to transform the campus landscape into a welcoming portal to engage visitors with the creative work and spirit of inquiry at UC Davis. Visit GATEways Gardens that have been co-created by UC Davis Arboretum and Public Garden staff with academic, community, and student partners. Gardens highlighting the academic disciplines of geology, Native American studies, animal science, veterinary medicine, and entomology will be the focus of the tour. Some of the gardens feature magnificent oak trees as well! In addition, meet UC Davis students in the Arboretum and Public Garden’s Learning by Leading™ program who gain leadership skills through their work on creating and enlivening GATEways Gardens. The tour will conclude at Peter J. Shields Oak Grove for an exploration of the tree collection and art features made in collaboration with the Art-Science Fusion program. UC Davis Arboretum and Public Garden Assistant Director Carmia Feldman and GATEways Horticulturist Ryan Deering will lead this tour.

UC Davis Arboretum Collections Tour
Join renowned Superintendent Emeritus of the UC Davis Arboretum and Public Garden, Warren Roberts, and GATEways Horticulturist Stacey Parker for a tour of significant oaks and other notable plants in the Arboretum’s gardens and collections.  The tour will highlight the Arboretum’s California native plant collections as well as geographic collections of plants from the Southwestern United States, Mexico, and the Mediterranean region. The tour will end in Peter J. Shields Oak Grove with the Arboretum’s most diverse and significant tree collection. Warren started his career as Superintendent of the Arboretum in 1972 and is known for his encyclopedic horticultural knowledge.  Always engaging, Warren is a famous storyteller and punster, and never fails to deliver a unique introduction to the UC Davis Arboretum's gardens and collections. Stacey Parker joined the horticultural staff in 2012 and currently supervises the care of the Arboretum’s collections.

Shields Oak Grove Deep Immersion Tour
Join quercophiles Emily Griswold and Dave Muffly for an in-depth exploration of Peter J. Shields Oak Grove, the UC Davis Arboretum and Public Garden’s premier scientific tree collection.  Since the first tree was planted in 1962, the collection has grown to over 300 trees and has served as a living laboratory for oak research, a long-term experiment in tree performance and adaptability, a learning site for students, and a source of inspiration for generations of visitors. As Director of GATEways Horticulture and Teaching Gardens, Emily leads the care and development of the grove, where she started working on projects in 1998. Dave, a noted arborist, has visited the grove since 2003, collecting acorns, growing seedlings, and attempting to glean evidence for the introduction of new oak taxa into the urban forests of coastal California.

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Historical ecology of Northern California: learning from the past to prepare for the future
In this highly visual tour, we will explore local landscapes of the recent past, from the vast wetlands of the Delta to the grand oak savannas of surrounding valleys, to discover the remarkable transformation and resilience of California's landscapes. The presentation will draw on historical ecology analyses conducted over the past 2 decades, with particular attention to the insights historical ecology can provide as we attempt to design more resilient landscapes for the future.
Robin Grossinger

Robin Grossinger is a Senior Scientist at the San Francisco Estuary Institute, where he co-directs SFEI’s Resilient Landscapes program. For over twenty years, Robin has analyzed how California landscapes have changed since European contact, using these data to guide landscape-scale restoration strategies. Robin leads efforts throughout the state to reintegrate natural processes within our highly modified landscapes, creating healthier and more adaptive neighborhoods, cities, and surrounding landscapes. He has helped develop restoration strategies for San Francisco Bay, the Sacramento-San Joaquin Delta, urban landscapes such as the Google campus, and rivers throughout California.

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