May 15, 2013

Learning in the Arnold Arboretum landscape

Spring flowers and new leaves at the Arnold Arboretum of Harvard University signal the return of schoolchildren for outdoor field study experiences. For three decades, the Arboretum has reached out to students from Boston Schools to participate in structured explorations of the collections, life science instruction, and engaging interactions with the natural world. This season the Arboretum welcomes hundreds of science students from pre-school through primary grades with new programs, an enhanced partnership for in-class instruction at a neighborhood elementary school, and six additional volunteer guides.

Beginning in April, young explorers delve into the landscape through five educational programs designed for hands-on learning. The youngest participants—pre-schoolers from Head Start and kindergarten students—discover plants, animals, and habitats in the Explorations program. Boston’s first grade students explore living things and their habitats in the Organisms program, and second grade students compare plants grown in the classroom with the Arboretum’s mature tree specimens in Old Plants. Upper elementary school grades investigate how flowers make seeds in Flowers Change, and compare evergreen conifers and deciduous flowering trees and their cultural uses in Native Trees/Native Peoples.

Over the past five years, the Arboretum has enhanced the value of its Field Studies experiences for local students through partnerships for in-class science instruction. Arboretum educators will continue to visit classrooms at the Boston Teachers Union (BTU) School in Jamaica Plain this spring, supporting teachers and helping facilitate science instruction on a weekly basis. Science Specialist Ana Maria Caballero will also visit classrooms of a pre-school partner, ABCD South Side Head Start, to lead activities focused on plants that include observation, drawing, collage, and painting.

The Arboretum’s programs for schoolchildren depend on the dynamic participation of volunteer guides, and with the addition of six new recruits this spring, the corps now comprises 40 individuals. Training commenced in March and provided an opportunity for seasoned guides to help mentor their new colleagues. Trainees learned the curricula and practiced techniques for teaching children in outdoor settings, working in groups to explore the living collections and build cohesion as a team.

As a fundamental part of the institution’s public mission, programs for children’s education initiate a continuum for lifetime learning at the Arnold Arboretum. In celebration of the scope and accomplishments of these programs and specifically its partnership for in-class instruction, the Arboretum will mount an exhibition of observational drawings of plants and other organisms by students at the BTU School. “Through a Child’s Eye” will be on view in the Hunnewell Building Lecture Hall from June 15 through September 1, 2013.

May 8, 2013

Arboretum Explorer in the landscape.

Last May on Lilac Sunday, the Arnold Arboretum of Harvard University introduced visitors and online audiences to two mobile applications for mapping and sharing information on the Arboretum’s living plant collections—Mobile Interactive Map (MIM) and Arboretum Navigator. Following a year of rigorous testing and evaluation, the Arboretum has combined the best attributes of both in a single application, Arboretum Explorer. Set for launch on May 12 as part of this year’s Lilac Sunday celebrations, Arboretum Explorer represents the latest advance in the Arboretum’s historical commitment to expanding access to its collections for science, learning, and recreation.

All of the more than 15,000 accessioned plants at the Arnold Arboretum are mapped, recorded, and tracked digitally with the help of a collections database, BG-BASE. Arboretum Explorer allows users to tap into this information by harnessing the GIS (geographic information system) capabilities of their mobile phones and tablets to locate and identify specific plants in the landscape. Arboretum Explorer also significantly enhances how visitors interact with plants they encounter in the collection, from taking self-guided tours to finding information on Tree Mobs and sharing plants on social media.

“As stewards of one of the world’s most important living collections of plants, our charge is to do everything we can to share information and insight into our extraordinary trees, shrubs, and vines,” said Director William (Ned) Friedman. “It’s a big part of what has made the Arboretum a hugely valuable resource to school children, the visiting public, and scientists from around the globe. We are committed to pushing the digital frontiers that connect people to our plants and promote greater interactions with biodiversity.”

Try out Arboretum Explorer on your mobile device this Lilac Sunday, at home, or on your next Arnold Arboretum visit. The Arboretum requests continued feedback from users to help identify new features and guide the engineering of future releases.

May 1, 2012

A living fossil with an ancestry dating back some 270 million years, Ginkgo biloba stands out in the plant world as an object of fascination. A deciduous gymnosperm that persists as a single genus and species, Ginkgo offers scientists a unique glimpse at our botanical and evolutionary past. To celebrate this relict species and explore its botanical importance and relevance in our time, three eminent ginkgo researchers will share their expertise as part of a full-day symposium—Ginkgo Fest—at the Arnold Arboretum on Saturday, May 11 (this event was rescheduled from April 20).

Sir Peter Crane, Dean of Forestry and Environmental Science at Yale; William “Ned” Friedman, Arnold Professor of Organismic and Evolutionary Biology at Harvard and Director of the Arnold Arboretum; and Peter Del Tredici, Senior Research Scientist at the Arnold Arboretum and ginkgo specialist, will lecture on their combined fifty years of ginkgo investigations and lead a tour of the Arboretum’s ginkgo collection. The program will spotlight the history, culture, biology, and conservation of ginkgo, and displays will include examples of ginkgo bonsai created by Peter Del Tredici.

Recognized by its fan-shaped leaves and known for both the beauty of its autumn foliage and the fetid odor of its fruits, Ginkgo has its share of enthusiasts and detractors. The tree and its seeds—when removed from the fleshy and odorous fruits—have been an integral part of Chinese and Japanese culture for centuries. Once distributed throughout the Northern Hemisphere but now native only to central China, Ginkgo has made a resurgence in the temperate zones, finding wide use as a street tree and as an ornamental favorite in managed landscapes.

In his book, Ginkgo: The Tree That Time Forgot, Peter Crane writes, “Ginkgo is one of the world’s most distinctive plants and has one of the longest botanical pedigrees; there is no other living tree with a prehistory so deeply intertwined with that of our planet.” The Arboretum’s Ginkgo Fest celebration honors the tree’s unique biology and its critical role in helping us unravel Earth’s deep past. At the same time, as a plant with an ancient history of adapting to challenging and disturbed environments, Ginkgo biloba continues to excite scientists for what it may reveal about the future of plant life in a changing climate.

April 29, 2012

Horticulture staff plant Acer rubrum #567-2008*B as an April 15 memorial planting.

Though spring seemed to get a bit of a late start in Boston this year, spring planting is already well underway at the Arnold Arboretum. Staff horticulturists are adding many trees, shrubs, and vines from our nurseries to their new locations in the landscape. This season’s additions to the living collection—including about 75 individual trees—represent plants collected on botanical expeditions, species of conservation value, and adjuncts to several of the Arboretum’s national collections and visitor destinations.

Among the “class of 2013” are young specimens birch (Betula spp.), hornbeam (Carpinus spp.), and holly (Ilex spp.), to name just a few. Many new accessions of species and ornamental roses will enhance new beds established last fall at the entrance to the Bradley Rosaceous Collection. Plants obtained on a 2008 staff expedition to the Adirondack Mountains are also finding their way into the landscape this spring, including red maple (Acer rubrum), mountain maple (A. spicatum), and two species of cherry (Prunus serotina and P. virginiana). The red maple, Accession #567-2008*B, was planted on Arbor Day during a special gathering and tour in the Maple Collection, and honors those who lost their lives or were injured in connection with the Boston Marathon bombing on April 15.

New maples represent an enhancement of the Arboretum’s “national collection” of the genus, grown in association with the U.S. Department of Agriculture. Other additions to Arboretum national collections include American beech (Fagus grandifolia) and two stewartias, mountain stewartia (Stewartia ovata) and upright stewartia (S. rostrata). An exceedingly rare species in the wild, S. rostrata was collected in China by Senior Research Scientist Peter Del Tredici, and joins a stewartia grove established near the burial ground on Peters Hill. Peters Hill will also receive 10 new individuals of Malus sieversii from Kazakhstan, believed by some to be the “progenitor apple” for all of our cultivated varieties.

The Arboretum’s horticulture staff plants mostly deciduous plants in the spring (April to early June) and coniferous plants in the fall (September to October). Trees growing in our nurseries that are intended for spring planting are dug before they leaf out, and planted in locations selected by the Curator of Living Collections and the Director of Operations. Once planted, new accessions are monitored closely by staff for their first few seasons until they are well established. If you’d like to spot the newest additions to our collections on your next Arboretum visit, look for young plants in the landscape marked by yellow-colored stakes.

April 17, 2012

The Arnold Arboretum is launching a new series of free public events this spring, each highlighting outstanding plant collections at their peak. Collections Up Close events delve into the diversity of the Arboretum’s Living Collection and celebrate thoughtful observations of the natural world. Through staff-led tours, fun science and art activities for kids, scavenger hunts, and interactions with plant experts, participants will discover new ways to explore the Arboretum and its plants.

The first event in the 2013 series is Magnificent Maples on April 21 from 1:00 to 3:00pm. According to Julie Warsowe, Manager of Visitor Education, “Collections Up Close events focus attention on plants at their peak—though perhaps not the ‘peak’ you would expect. While some might think of maples during sugaring season or in the fall when their leaves change color, the delicate beauty and complexity of maple flowers inspires wonder as well. Once you look closely, you begin to notice details that reveal the wonderful diversity of these trees.”

Magnificent Maples will feature tours of the collection led by Michael Dosmann, Curator of Living Collections, and Nancy Rose, Editor of Arnoldia. Dr. Joshua Rapp of Harvard Forest will share his research on the relationship between maple flowering and maple syrup production. Families can enjoy a scavenger hunt, a maple flower observation station, and a photography workshop with the Boston Parks & Recreation Department’s ParkSCIENCE program.

Lilac Sunday (May 12, 10:00am to 4:00pm), a beloved Boston tradition, also fits within the Collections Up Close theme. While this year’s celebration will still spotlight the Arboretum’s extensive lilac collection, it will also encourage visitors to explore other impressive collections in bloom in mid May, from the Bradley Rosaceous Collection to the Explorers Garden. Family activities on Lilac Sunday will encourage children to observe lilacs and other spring bloomers, with an emphasis on pollinator relationships.

On June 2 from 1:00 to 3:00pm, a third Collections Up Close event will highlight the Arboretum’s rhododendron collection along Rhododendron Dell. This beautiful shaded area at the foot of Hemlock Hill provides an ideal growing location for some 280 hybrid and broadleaf evergreen rhododendrons including North American, Asian, and hybrid types.

All events are free. Registration is not required. See details on event locations, a full schedule [pdf], and inclement weather plans.

March 18, 2012

The Arnold Arboretum of Harvard University is pleased to announce that Senior Research Scientist Peter Del Tredici will be awarded the Veitch Memorial Medal in London this spring. The Royal Horticultural Society presents this prestigious, international award to “persons of any nationality who have made an outstanding contribution to the advancement and improvement of the science and practice of horticulture.”

The award recognizes Dr. Del Tredici’s extensive work on numerous aspects of both botany and horticulture over the past forty years. His wide ranging interests include new plant introductions from China, the root systems of woody plants, the natural and cultural history of ginkgo, and urban ecology and vegetation, a subject he explores in his recent book, Wild Urban Plants of the Northeast: A Field Guide (Cornell University Press, 2010). He has lectured widely in North America and Europe and has authored more than 130 scientific and popular articles. Dr. Del Tredici joins the select company of five other Arboretum staff members who received the Veitch Memorial Medal: Founding Director Charles Sprague Sargent (1896), plant explorer and Keeper of the Arboretum Ernest Henry Wilson (1906), Propagator William H. Judd (1944), Horticulturist Donald Wyman (1968), and Curator and Horticultural Taxonomist Stephen A. Spongberg (1996).

Peter Del Tredici holds a BA degree in zoology from the University of California, Berkeley (1968), a MA degree in biology from the University of Oregon (1969), and a PhD in biology from Boston University (1991). He has worked at the Arnold Arboretum of Harvard University since 1979, as a plant propagator, editor of Arnoldia, Director of Living Collections, and, most recently, Senior Research Scientist. Since 1984, Peter has served as curator of the Arboretum’s renowned Larz Anderson Bonsai Collection. Dr. Del Tredici is also an Adjunct Associate Professor in the Department of Landscape Architecture at the Harvard Graduate School of Design, where he has been teaching courses on plants, soil and ecology since 1992. He was the winner of the Arthur Hoyt Scott Medal and Award for 1999, presented annually by the Scott Arboretum of Swarthmore College and in January 2013, he was recognized by the Garden Club of America as an honorary member.

Dr. Del Tredici will receive the Veitch Memorial Medal at ceremonies on May 20 at the Chelsea Flower Show. The Veitch Memorial Medal was founded in 1870 to honor James Veitch (1815-1869), whose family-run plant nurseries in Victorian England introduced hundreds of exotic plants and horticultural varieties into cultivation.

February 12, 2012

February 12 is Charles Darwin’s 204th birthday, cause for celebration here at the Arnold Arboretum. For twenty-four hours beginning after midnight, our homepage will feature a rotating set of Darwin’s quotations on trees and plant biodiversity.

Many of the key insights that Darwin used to make his case for evolution by natural selection came from his knowledge of plant domestication. Darwin keenly understood that if humans could employ artificial selection to create a myriad of horticultural varieties in mere hundreds to thousands of years, then nature, through tens and hundreds of millions of years, could yield immensely more! This is a reminder of the important role that botanical gardens, arboreta, and other natural history collections continue to play in making the evolutionary process familiar to all of us. Our collections of crabapples, lilacs, roses, rhododendrons, dwarf conifers, and many more provide living examples of random mutation, variation, and selection, the very stuff of evolution.

Take a few minutes to celebrate the life and work of Charles Darwin by viewing some amazing resources. The Darwin Correspondence Project is working to digitize more than 15,000 surviving pieces of correspondence, and Darwin Online shares digital copies of almost all of Darwin’s publications and private writings. In these databases, you will find much more than natural selection. Type in the keyword cherry and see what Darwin wrote about cherry trees in his various books. Or mulberry to find Darwin’s description of the trees on the property of Down House where many of his legendary experiments took place.

And finally, come today and often to the Arnold Arboretum. With some 15,000 curated woody plants and more than 2,200 species, the Arboretum is the perfect place to reflect on the depth of evolutionary time and the beauty of biodiversity.

William (Ned) Friedman
Director of the Arnold Arboretum
Arnold Professor of Organismic and Evolutionary Biology, Harvard University

January 31, 2013

Compact hinoki cypress (Chamaecyparis obtusa ‘Chabo-hiba’) #892-49*A, started in 1787, from the Larz Anderson Bonsai Collection

The Larz Anderson Bonsai Collection at the Arnold Arboretum celebrates its hundredth anniversary in America this year. The plants were originally imported in 1913 by the Honorable Larz Anderson, upon his return from serving as ambassador to Japan. The core of the collection consists of seven large specimens of compact hinoki cypresses Chamaecyparis obtusa ‘Chabo-hiba’—now between 151 and 276 years old—that Anderson purchased from the Yokohama Nursery Company. These plants provide a direct link to the early 1900s, when Americans and Europeans, infatuated with the Far East, were passionately collecting cultural artifacts from Japan.

Upon their arrival in the United States in 1913, the trees—then numbering around forty—resided at the Anderson estate in Brookline, Massachusetts. They lived there for nearly twenty-five years and were cared for by a succession of Japanese gardeners. The collection was donated to the Arnold Arboretum in two stages, initially in 1937 following Larz Anderson’s death, and later in 1948, following the death of his wife, Isabel. It was not until 1969, when Constance Derdarian was appointed curator, that a person knowledgeable in the art of bonsai took charge of bringing the collection back to health after years of neglect. Following Connie’s death in 1984, Senior Research Scientist Peter Del Tredici was appointed curator and further upgraded the care of the collection and initiated research into the origins of the plants in Japan. Colin Lewis, a specialist in bonsai art, has been working with Peter since 1998 to restore some of the large hinoki cypresses to their original “hachinoki” style. The fact that the Collection has survived the ravages of both time and occasional neglect for the past century is not only a testament to the care it has received, but also to the incredible durability of the plants themselves.

While the sixteen plants that currently make up the Larz Anderson Collection are not the oldest dwarfed plants in the United States, they have been under cultivation longer than any other examples currently growing in North America—with the lone exception of three plants at the Brooklyn Botanic Garden that were imported in 1911. The Arboretum plans a number of special events this fall to celebrate the beauty and historical importance of this singular collection of dwarfed plants; details will be announced this spring. Currently off display for the winter, the Collection will return to public view in April.

Read a related Arnoldia article on the history [pdf] of the Larz Anderson Bonsai Collection, and another detailing their care and restoration [pdf].

November 30, 2012

Plans are underway in the Visitor Center for new display cases, a reading area, and and interactive technologies to be installed over the winter. According to Manager of Visitor Education Julie Warsowe, “our goal is for you to experience enhanced learning opportunities in the renewed space, and to give you new reasons to come back again and again—whether it’s to see a new exhibit with treasures from the Arboretum’s archives, browse new books on rotation from our library, or talk to a knowledgeable, friendly Arboretum representative.”

Also as part of these changes, the Visitor Center hours will be shifting. Beginning January 2, we will move to a seasonal schedule to better match visitation patterns. From November through March, the Visitor Center will be open from noon to 4:00pm every day except Wednesday. During these hours, the public areas of the Hunnewell Building will be open as usual—the Visitor Center, art exhibitions in the Lecture Hall (unless a class is in session), and restrooms. Before noon on weekdays, the Hunnewell Building will be open for restrooms and access for business guests. Library hours will remain the same.

This new schedule will provide our dedicated staff additional time outside the Visitor Center, developing more dynamic ways to share our seasonal highlights in the landscape, communicate the breadth and research use of the living collection, and make the rich resources of the Arboretum more accessible to visitors. In this new model, visitors will have more opportunities to engage directly with our staff, whether inside the Visitor Center or in its surrounding landscape.

This spring, the Visitor Center hours will increase as we head into our peak period of visitation. From April through October we plan for the Visitor Center to be open from 11:00am to 6:00pm every day except Wednesday, with weekday use of the restrooms and access for business guests beginning at 9:00am. Please stop by to see the work in progress this winter, and stay tuned for a celebration of the improved Visitor Center this spring.

November 28, 2012

Visiting researcher Erica Fadon from Aula Dei-CSIC, Spain, samples flowers of Prunus incisa f. serrata (AA #172-95*B) in November near Faxon Pond.

Although there are notable exceptions, the majority of flowering plants in the Arnold Arboretum’s Living Collection bloom over the course of spring and early summer. While it is normal for some plants like the Franklin tree (Franklinia alatamaha) to flower in early fall, the autumn or winter occurence of flowers on plants that normally bloom in spring can be a surprising sight in the landscape. Why do some plants flower again during the off season? Is it a sign of climate change?

For Iñaki Hormaza, a Research Associate of the Arnold Arboretum and Professor at the Mayora Research Station of the Spanish Council for Scientific Research (CSIC), this phenomenon provides an opportunity to study how plants regulate their biological functions. “As temperatures start to drop after summer,” he explains, “flower buds enter a dormant stage to help them to survive harsh winter conditions.” The duration of this dormancy is specific for each plant, but usually lasts the entire winter. “Once the plant has accumulated its required number of cold hours,” he adds, “warmer temperatures induce flowering.”

However, in some cases, such as the Fuji cherry (Prunus incisa f. serrata) near Faxon Pond pictured here, the required dormancy may be quite brief, and warm days in November or December may trigger early flowering. Atypical flowering behavior may be related to flower developmental arrest resulting from environmental stresses like low temperatures or drought in early fall followed by warm and rainy weather. It is likely that this situation may be observed more often in the future as global climate change delivers more frequent irregularity in weather patterns. The Arnold Arboretum’s extensive collections provide ample opportunity to study dormancy to understand how crucial biological functions like flowering may be impacted by incremental shifts in our environment.