DOCSLIB.ORG

Thirty‐Two Years of Change in an Old‐Growth Ohio Beech–Maple Forest

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Thirty‐Two Years of Change in an Old‐Growth Ohio Beech–Maple Forest Ecology, 94(5), 2013, pp. 1165–1175 Ó 2013 by the Ecological Society of America Thirty-two years of change in an old-growth Ohio beech–maple forest 1 JAMES R. RUNKLE Department of Biological Sciences, Wright State University, Dayton, Ohio 45435 USA Abstract. Old-growth forests dominated by understory-tolerant tree species are among forest types most likely to be in equilibrium. However, documentation of the degree to which they are in equilibrium over decades-long time periods is lacking. Changes in climate, pathogens, and land use all are likely to impact stand characteristics and species composition, even in these forests. Here, 32 years of vegetation changes in an old-growth beech (Fagus grandifolia)–sugar maple (Acer saccharum) forest in Hueston Woods, southwest Ohio, USA, are summarized. These changes involve canopy composition and structure, turnover in snags, and development of vegetation in treefall gaps. Stand basal area and canopy density have changed little in 32 years. However, beech has decreased in canopy importance (49% to 32%) while sugar maple has increased (32% to 47%). Annual mortality was about 1.3% throughout the study period. Mortality rates increased with stem size, but the fraction of larger stems increased due to ingrowth from smaller size classes. Beech was represented by more very large stems than small canopy stems: over time, death of those larger stems with inadequate replacement has caused the decrease in beech importance. Sugar maple was represented by more small canopy stems whose growth has increased its importance. The changes in beech and sugar maple relative importance are hypothesized to be due to forest fragmentation mostly from the early 1800s with some possible additional effects associated with the formation of the state park. Snag densities (12–16 snags/ha) and formation rates (1–3 snagsÁhaÀ1ÁyrÀ1) remained consistent. The treefall gaps previously studied are closing, with a few, large stems remaining. Death of gap border trees occurs consistently enough to favor species able to combine growth in gaps and survival in the understory. Key words: Acer; disturbance; Fagus; fragmentation; Hueston Woods, Ohio; long-term study; old growth forest; snag; tree demography; treefall gaps. INTRODUCTION Oliver and Larson (1996) state that true old-growth Models of forest dynamics, often framed in terms of forests have probably never been common because ecological succession, predict a series of changes in the major disturbances occur quite frequently in most areas forest as it ages, including increases in biomass and compared to the life spans of trees. Pickett et al. (2009) shifts in species composition from fast-growing light- state that stabilization of vegetation composition or demanding species to those better able to survive in the structure is recognized to be a rare outcome of understory until their opportunity to reach the canopy vegetation dynamics at many spatial and temporal occurs (e.g., Whittaker 1975, Perry et al. 2008). If scales and in many habitats. However, in parts of the disturbances are infrequent enough, this process results Lake States and in parts of the central eastern deciduous in a steady state or equilibrium community in which the forest, such forests may have been frequent (Runkle dominant canopy species also reproduce well. At that 1996, Frelich 2002, Perry et al. 2008). stage, the community will change relatively little in It is not clear which aspect of forests is the best species composition or ecosystem properties until some indicator of old-growth conditions. Bormann and new disturbance occurs. This simple model, based on Likens (1979) used stand biomass as an indicator: in ideas from Clements (1936) and their subsequent old-growth forests, biomass fluctuations should be development (Pickett et al. 2009), provides a useful minor compared to the mean value. They proposed a framework. However, it leaves several questions unan- shifting-mosaic steady state model in which the ecosys- swered. tem as a whole is in equilibrium although at any one Are there locations and forests in which disturbances location it changes with the establishment, growth, and are rare enough that a steady state community exists? death of individual canopy trees. Oliver and Larson (1996) consider true old growth to occur when all trees that invaded immediately after the last major distur- Manuscript received 8 December 2011; revised 25 October bance have died. They do not assume that species 2012; accepted 13 November 2012; final version received 6 December 2012. Corresponding Editor: J. J. Battles. composition will remain constant at that time but are 1 E-mail: [email protected] unclear under what conditions it might change. Frelich 1165 1166 JAMES R. RUNKLE Ecology, Vol. 94, No. 5 (2002) uses the definition of Clements (1936) that the The opportunity for measuring these features of old- climax forest will be able to reproduce its own growth mesic forests in some forest types is very limited. composition in the absence of severe disturbance. Perry Few old-growth remnants exist in some areas of fertile et al. (2008) also characterize the steady state forest as agricultural soils (Davis 1996). Available sites are one in which species composition becomes relatively further restricted by several recently introduced and stable if species reproduce under their own canopies or spreading pathogens and pests affecting such important in small gaps. trees as American beech (Fagus grandifolia), ash It is uncertain how much change occurs in the final (Fraxinus spp.), eastern hemlock (Tsuga canadensis), stage. At that stage, most tree death occurs as single and, to a lesser extent, sugar maple (Acer saccharum) treefalls (referred to here as gaps) or, at most, small (Griffin et al. 2003, Small et al. 2005, Watmough 2010, clusters of treefalls. The frequency of such deaths Garnas et al. 2011, Kashian and Witter 2011). Such undoubtedly varies from year to year. It is not known increased recent mortality obscures the disturbance how variable over short (a few years) to medium (a few regimes under which current tree species have evolved. decades) time spans are mortality rates, stand charac- Hueston Woods State Park in southwestern Ohio, teristics such as total basal area and total density, and USA, is an ideal place to examine the nature of an old- species composition. growth mesic forest. It is dominated by two long-lived In many parts of eastern North America, the mesic species, beech and sugar maple. There is no indication of a major overstory disturbance for several disturbance regime is dominated by individual treefalls tree generations. It is one of the very few old-growth and replacement in the resultant canopy gaps (Runkle forest stands in this forest type and has not yet been 1990, 1998, Lorimer et al. 2001, Busing 2005, D’Amato impacted by invasive tree pathogens. My 32-yr study and Orwig 2008, Gravel et al. 2010). Several generaliza- there allows me to distinguish between trends and tions about this disturbance regime are possible. fluctuations and allows me to quantify variations Average annual mortality is about 1% for trees around average conditions. I will examine (1) the corresponding to average canopy residence times of dynamics of canopy trees, including their rates of about a century for many tree species (Runkle 1996, growth, mortality, and replacement overall, by species Tyrrell et al. 1998). Less clear is the degree to which and by size class; (2) the dynamics of snags (dead stems mortality varies over short to moderate time periods. It .1.5 m high); and (3) changes in the vegetation of also is not clear what deviations around that 1% figure treefall gaps originally sampled in 1977. entail and why mortality in some forest types is consistently greater than 1% while in other forest types METHODS it is consistently less. Study area Related to the stand structure of living trees is the The study site is a 67-ha old-growth stand in Hueston stand structure of dead trees and other coarse woody Woods State Park, Ohio, USA (398340 N, 848450 W). debris (see Plate 1). Those components of the forest are That stand has remained relatively undisturbed since its important for many species, including birds and other purchase in 1797. Its overstory is dominated by beech vertebrates, fungi and other decomposers, and plants and sugar maple with white ash (Fraxinus americana), (Harmon et al. 1986, Hura and Crow 2004, Garber et al. tulip tree (Liriodendron tulipifera), and black cherry 2005, Siccama et al. 2007). Some information on these (Prunus serotina) as codominants in some areas. Soils resources is accumulating (Tyrrell et al. 1998) but some are Russell silt loams (a Typic Hapludalf) and are deep forest types, including the beech–maple forest type, have and well drained, having formed in silt-mantled glacial been the focus of relatively few studies. Standing dead till overlying limestone (Lerch et al. 1969). Summers are trees (snags) are of particular interest with regard to hot (mean July temperature 23.78C), winters are cold forest change because they are ephemeral. Some trees die (mean January temperature À2.08C), and precipitation and immediately become fallen logs. Others die standing occurs year-round (mean annual precipitation 102.5 cm or broken off and gradually deteriorate. The time during [averages 1950–1988 for Hamilton, Ohio; National which they remain standing is an important component Climatic Data Center]). Braun (1950) included it in her of the forest habitat for many species. Long-term studies characterization of the beech–maple forest region and are necessary to determine the rates at which snags form, recognized three topographic areas: upland, slope, and the rates at which they deteriorate and the variation in lowland; elevation ranges from 268–296 m above sea the availability of this resource through time. level. More recently it has been the subject of several A third component of forest change is the filling of studies on forest dynamics (Vankat et al.
Load more

Recommended publications
  • Chagrin River Watershed Action Plan
    Chagrin River Watershed Action Plan Chagrin River Watershed Partners, Inc. PO Box 229 Willoughby, Ohio 44096 (440) 975-3870 (Phone) (440) 975- 3865 (Fax) www.crwp.org Endorsed by the Ohio Environmental Protection Agency and Ohio Department of Natural Resources on December 18, 2006 Revised December 2009 Updated September 2011 i List of Tables ............................................................................................................................................... vi List of Figures ............................................................................................................................................. vii List of Appendices ..................................................................................................................................... viii Acknowledgements ....................................................................................................................................... x Endorsement of Plan by Watershed Stakeholders ....................................................................................... xi List of Acronyms ........................................................................................................................................ xii 1 Chagrin River Watershed ............................................................................................................. 1 1.1 Administrative Boundaries .......................................................................................................... 1 1.2 History of Chagrin
    [Show full text]
  • Cleveland Tree Plan Appendix a – Guide for Species Selection
    Appendix A A Guide for Species Selection Managing trees in a changing climate is challenging for arborists Right Tree Right Place. Improperly siting trees can result and urban foresters. Species that are currently thriving could decline in economic, environmental, and social losses to the as future climatic conditions alter weather events and patterns. community. The “right tree right place” maxim is central Local knowledge and expertise of Cleveland’s urban forest was to changing the conversation around trees, specifically with utilized to produce the following guide for the selection of trees that respect to thinking of trees as assets versus liabilities (Arbor can tolerate extreme environmental conditions. Day Foundation). Tree planting and transplanting projects Trees were selected and compiled into a recommended species list should carefully consider plant characteristics at maturity, for Cleveland’s urban forest by Holden Arboretum’s Plant above- and below-ground site factors, and urban forest Collection and Records Curators. This list is intended to aid species composition. selection for public and private land across the community with A unique tool is also available to assess the urban site index consideration given to trees that tolerate urban conditions like (USI) developed by regional urban foresters at the Ohio compaction, drought, pollution, and salt. Department of Natural Resources Division of Forestry Specific characteristics were considered in selecting species that (Leibowitz 2012). The tool utilizes a rapid assessment of could collectively contribute to a more sustainable urban and factors to score sites between 0 and 20 as a means to community forest, including the promotion of diversity, selective identify planting suitability.
    [Show full text]
  • Conifer Quarterly
    Conifer Quarterly Vol. 24 No. 4 Fall 2007 Picea pungens ‘The Blues’ 2008 Collectors Conifer of the Year Full-size Selection Photo Credit: Courtesy of Stanley & Sons Nursery, Inc. CQ_FALL07_FINAL.qxp:CQ 10/16/07 1:45 PM Page 1 The Conifer Quarterly is the publication of the American Conifer Society Contents 6 Competitors for the Dwarf Alberta Spruce by Clark D. West 10 The Florida Torreya and the Atlanta Botanical Garden by David Ruland 16 A Journey to See Cathaya argyrophylla by William A. McNamara 19 A California Conifer Conundrum by Tim Thibault 24 Collectors Conifer of the Year 29 Paul Halladin Receives the ACS Annual Award of Merits 30 Maud Henne Receives the Marvin and Emelie Snyder Award of Merit 31 In Search of Abies nebrodensis by Daniel Luscombe 38 Watch Out for that Tree! by Bruce Appeldoorn 43 Andrew Pulte awarded 2007 ACS $1,000 Scholarship by Gerald P. Kral Conifer Society Voices 2 President’s Message 4 Editor’s Memo 8 ACS 2008 National Meeting 26 History of the American Conifer Society – Part One 34 2007 National Meeting 42 Letters to the Editor 44 Book Reviews 46 ACS Regional News Vol. 24 No. 4 CONIFER QUARTERLY 1 CQ_FALL07_FINAL.qxp:CQ 10/16/07 1:45 PM Page 2 PRESIDENT’S MESSAGE Conifer s I start this letter, we are headed into Afall. In my years of gardening, this has been the most memorable year ever. It started Quarterly with an unusually warm February and March, followed by the record freeze in Fall 2007 Volume 24, No 4 April, and we just broke a record for the number of consecutive days in triple digits.
    [Show full text]
  • 2021 Reciprocal Admissions Program
    AMERICAN HORTICULTURAL SOCIETY 2021 RECIPROCAL ADMISSIONS PROGRAM Participating Gardens, Arboreta, and Conservatories For details on benefits and 90-mile radius enforcement, see https://ahsgardening.org/gardening-programs/rap Program Guidelines: A current membership card from the American Horticultural Society (AHS) or a participating RAP garden entitles the visitor to special admissions privileges and/or discounts at many different types of gardens. The AHS provides the following guidelines to its members and the members of participating gardens for enjoying their RAP benefits: This printable document is a listing of all sites that participate in the American Horticultural Society’s Reciprocal Admissions Program. This listing does not include information about the benefit(s) that each site offers. For details on benefits and enforcement of the 90- mile radius exclusion, see https://ahsgardening.org/gardening-programs/rap Call the garden you would like to visit ahead of time. Some gardens have exclusions for special events, for visitors who live within 90 miles of the garden, etc. Each garden has its own unique admissions policy, RAP benefits, and hours of operations. Calling ahead ensures that you get the most up to date information. Present your current membership card to receive the RAP benefit(s) for that garden. Each card will only admit the individual(s) whose name is listed on the card. In the case of a family, couple, or household membership card that does not list names, the garden must extend the benefit(s) to at least two of the members. Beyond this, gardens will refer to their own policies regarding household/family memberships.
    [Show full text]
  • Conserving Oaks in North American Plant Collections: a Collaborative Approach
    Conserving Oaks in North American Plant Collections: A Collaborative Approach Emily Griswold Assistant Director of Horticulture UC Davis Arboretum, University of California, Davis, CA 95616 As much as any ardent collector would love to comprehensively represent the variety of the genus Quercus in her garden, the great taxonomic diversity, range of natural habitats, and large mature size of oaks make that virtually impossible. With that in mind, a new cooperative group of American public gardens has recently formed with the goal of representing the oak diversity of North America in its collections. The 15 member gardens were recently recognized as the first multi-institutional collection of the North American Plant Collections Consortium (NAPCC). The members of the multi-institutional Quercus collection include: Chicago Botanic Garden – Glencoe, Illinois - 48 taxa Cornell Plantations – Ithaca, New York - 77 taxa Denver Botanic Gardens – Denver, Colorado - 61 taxa Holden Arboretum – Kirtland, Ohio - 64 taxa Landis Arboretum – Esperance, New York - 14 taxa Missouri Botanical Garden – Saint Louis, Missouri - 40 taxa Morris Arboretum of the University of Pennsylvania – Philadelphia, Pennsylvania - 58 taxa The Morton Arboretum – Lisle, Illinois - 67 taxa Mount Auburn Cemetery – Cambridge, Massachusetts - 25 taxa New York Botanical Garden – Bronx, New York - 46 taxa Rancho Santa Ana Botanic Garden – Claremont, California - 27 taxa Scott Arboretum of Swarthmore College – Swarthmore, Pennsylvania - 52 taxa UC Davis Arboretum – Davis, California - 92 taxa University of California Botanical Garden – Berkeley, California - 71 taxa University of Washington Botanic Gardens – Seattle, Washington - 86 taxa A program of the American Public Gardens Association, the NAPCC is a coordinated network of public gardens dedicated to preserving and expanding the plant diversity represented in gardens for the purposes of conservation, research, education, and public enjoyment.
    [Show full text]
  • Collections Policy
    Chicago Botanic Garden COLLECTIONS POLICY 1 Collections Policy July 2018 2 COLLECTIONS POLICY TABLE OF CONTENTS Mission Statement ................................................................................................................... 1 Intent of Collections Policy Document ..................................................................................... 1 Purpose of Collections .............................................................................................................. 1 Scope of Collections ................................................................................................................. 1 1) Display Plant Collections .......................................................................................... 2 Seasonal Display Collections ........................................................................... 2 Permanent Display Gardens ............................................................................ 2 Aquatic Garden ................................................................................... 2 Bonsai Collection ................................................................................. 3 Graham Bulb Garden .......................................................................... 3 Grunsfeld Children’s Growing Garden ................................................. 3 Circle Garden ....................................................................................... 3 Kleinman Family Cove ........................................................................
    [Show full text]
  • Conifer Quarterly
    Conifer Quarterly Vol. 26 No. 2 Spring 2009 Picea abies ‘Reflexa’ Photo by Dennis Groh The Conifer Quarterly is th e pub lication of the American Conifer Society Contents 7 How I spruced up Georgia by Tom Cox 10 A Fungus Made Us Do It by Bill Van Kosky 17 Brassica hirta by Phil Syphrit 19 Stonehedge, the Garden of Ken and Elena Jordan Text and Photos by Jack Ayers 26 Winter Burn on Conifers by Ellen Kelley 28 Evaluating Landscape Adaptability of Hemlock Species Picea abies 'Lanham's Beehive' ( spp.) in Western North Carolina Photo by Randall C. Smith, Courtesy of Iseli Nursery Tsuga by Anthony V. LeBude and Thomas G. Ranney 32 Collecting Northern Conifers by William Journeay 36 Conifer Destinations by Tom Cox 38 Conifers with Leaves by Maud Henne American Conifer Society Voices 2 President’s Message 4 Editor’s Memo 16 Letter to the Editor 41 ACS 2009 National Meeting 44 2009 Western Region Meeting 46 $7,000 Awarded to Four Southeast Regional Gardens Picea omorika ‘Pimoko’ Photo by Randall C. Smith, Courtesy of Iseli Nursery Vol. 26 No. 2 CONIFER QUARTERLY 3 Conifer AS I SEE IT FROM THE PRESIDENT ’S DESK “Everything is connected to everything At the recently concluded Winter way to recruit new members. else. There is one ecosphere for all living Board Meeting, the board focused on The charge to each region, then, is to Quarterly organisms and what affects one, affects membership. Our concern is not as much develop a plan to increase membership in all. ” with members who do not renew their region.
    [Show full text]
  • Small Forest Patches for Birds a Guide for Ohio Landowners About This Guide
    Managing Small Forest Patches for Birds A Guide for Ohio Landowners About this Guide This guide is written for land managers and property owners of small woodlots seeking to improve forest conditions for birds across their Contents full annual life cycle: breeding, migration, and wintering. Recommendations are based on Acknowledgements 1 multiple research studies conducted in Ohio and Section 1: Executive summary of small forest 3 similar “small patch” forest ecosystems through patch management recommendations the Midwest and eastern North America. Section 2: Managing for small forest patches 4 and the full life cycle of Ohio birds Section 3: A guide to forest types in Ohio 8 Section 4: Incorporating small forest patches 12 into the landscape Section 5: Enhancing forest composition and 18 structure Section 6: Managing wet woods 26 Section 7: Additional considerations, beneficial 29 attractants, and harmful practices to avoid Section 8: Management techniques 33 Appendix: Common and scientific names for 38 referenced flora and fauna Literature Cited 40 Acknowledgements Financial support: The majority of funding for this work has been provided through the Ohio Department of Natural Resources (ODNR)–Division of Wildlife and the U.S. Fish and Wildlife Service through the State Wildlife Grant program, the Federal Aid in Wildlife Restoration Program (W-134-P, Wildlife Management in Ohio), and the Ohio Wildlife Diversity and Endangered Species Fund, which consists of funds raised through the state income tax check-off program, sales of the Ohio Wildlife Legacy Stamp, and the purchase of Cardinal license plates. Printing of this publication was funded by Holden Forests & Gardens, which operates The Holden Arboretum and Cleveland Botanical Garden.
    [Show full text]
  • 2012 Forest Health Highlights
    2012 Forest Health Highlights Michigan Department of Natural Resources Acknowledgments Forest Health Highlights is a summary of the condition of Michigan’s forests during 2012 and the work done to preserve and protect them by Forest Resources Division, Department of Natural Resources, www.michigan.gov/foresthealth. Written by: Michigan Department of Natural Resources Forest Resources Division staff Photographs and design by: Michigan Department of Natural Resources Marketing and Outreach Division staff Forest Resources Division staff United States Department of Agriculture Forest Service Michigan Department of Agriculture and Rural Development Michigan State University Michigan Technological University Maps and other information provided by: Michigan Department of Agriculture and Rural Development United States Department of Agriculture Forest Service Animal and Plant Health Inspection Service Michigan State University Extension The Michigan Department of Natural Resources is committed to the conservation, protection, management, use and enjoyment of the state’s natural and cultural resources for current and future generations. For more information, visit www.michigan.gov/dnr. Table of Contents Forest Resource Overview. 4 Michigan Department of Natural Resources Forest Health Program ......... 5 Feature: Harvesting Ash and American Beech Ahead of EAB and BBD Impacts ... 6 Insects & Diseases ......................................................... 8 Heterobasidion Root Disease ......................................... 9 Asian Longhorned
    [Show full text]
  • Breeding for Resistance to Tree Pests: Successes, Challenges, and a Guide to the Future Carolyn C
    Journal of Forestry, 2021, 96–105 doi:10.1093/jofore/fvaa049 Discussion Received May 12, 2020; Accepted October 16, 2020 Advance Access publication December 3, 2020 Discussion Breeding for Resistance to Tree Pests: Successes, Challenges, and a Guide to the Future Carolyn C. Pike, Jennifer Koch, and C. Dana Nelson Carolyn C. Pike ([email protected]), USDA Forest Service, State and Private Forestry, Eastern Region, West Lafayette, IN. Jennifer Koch ([email protected]), USDA Forest Service, Northern Research Station, Delaware, OH. C. Dana Nelson ([email protected]), USDA Forest Service, Southern Research Station, Forest Health Research and Education Center, Lexington, KY. Keywords: resistance breeding, shared stewardship, forest health, tree improvement Forests in North America are threatened by a myriad critically endangered on the International Union for of native and nonnative pests and pathogens, the latter Conservation of Nature (IUCN) Red List (Westwood of which are largely introduced via the international et al. 2017). Invasive pests threaten native forest species trade of raw wood products and live plants. The early at a time when reforestation is considered one of our twentieth-century arrival of white pine blister rust best options for mitigating the impacts of climate change (WPBR) (Cronartium ribicola) and chestnut blight (Goymer 2018, Bastin et al. 2019). (Cryphonectria parasitica) on imported seedlings devas- Invasive pests have devastated entire ecosystems tated forests across North America. Invasive species
    [Show full text]
  • Global Survey of Ex Situ Maple Collections
    Global Survey of Ex situ Maple Collections Botanic Gardens Conservation International June 2010 Contents Contents .................................................................................................................................................. 2 Acknowledgements ................................................................................................................................. 2 Summary ................................................................................................................................................. 3 Introduction ............................................................................................................................................ 4 Methods .................................................................................................................................................. 5 Results ..................................................................................................................................................... 7 General findings .................................................................................................................................. 7 Collections in the country of origin ..................................................................................................... 8 Collection balance ............................................................................................................................... 8 Ex situ collections representativeness ................................................................................................
    [Show full text]
  • DOWNLOAD a .Pdf of All the Oak Grove Exhibit Signs
    TESToak YOUR wisdom Welcome to Lift the flaps to check your answers. Shields Oak Grove What do all oaks How many kinds of Where do oaks have in common? oaks are there? grow in the wild? Special Collections, Shields Library Shields Oak Grove is named for Judge Peter J. Shields, often called the father of the UC Davis campus. Judge Shields and his wife Carolee created a fund to provide support for the Arboretum’s land along the waterway. How tall do How long do What are oak oaks get? oaks live? apples? Debbie Aldridge Dr. John M. Tucker was a professor of botany, director of the Arboretum (1965-66 and 1972-84), and a prominent oak researcher. Many of the oaks in Shields Oak Grove were started in the 1960s from acorns collected from around the world for his research. Explore Shields Oak Grove to learn more about these amazing trees. Dr. Tucker created an endowment to help preserve the Grove for future generations. Contact the UC Davis Arboretum to learn J more about supporting Shields Peter . Shields Oak Grove Oak Grove and other giving arboretum.ucdavis.edu opportunities. Sign made possible by a grant from the Institute of Museum and Library Services TESToak YOUR wisdom Welcome to Lift the flaps to check your answers. Shields Oak Grove • Oaks are trees and shrubs that belong to the genus T r opic of Cancer Quercus, meaning “fine tree” Equator T r opic of Capricorn Allan Jones • Oaks have acorns—nuts that grow in a scaly cup Debbie Aldridge • There are approximately 500 species of oak Quercus trees and shrubs in the world • Oaks have tassel-like hanging Oaks are native to the Northern Hemisphere, from flowers; their pollen is • The UC Davis Arboretum collection includes the cold northern latitudes to tropical Southeast Asia Special Collections, Shields Library distributed by the wind about 100 species, varieties, and hybrids and Central America.
    [Show full text]