The Magazine of the Arnold Arboretum VOLUME 70 • NUMBER 3 The Magazine of the Arnold Arboretum VOLUME 70 • NUMBER 3 • 2013 CONTENTS Arnoldia (ISSN 0004–2633; USPS 866–100) 2 The Middlesex Fells, a Flourishing is published quarterly by the Arnold Arboretum Urban Forest of Harvard University. Periodicals postage paid Walter Kittredge at Boston, Massachusetts. Subscriptions are $20.00 per calendar year 12 The Quest for the Hardy Southern Live Oak domestic, $25.00 foreign, payable in advance. Michael S. Dosmann and Anthony S. Aiello Remittances may be made in U.S. dollars, by check drawn on a U.S. bank; by international 25 Mark Catesby: Pioneering Naturalist, Artist, money order; or by Visa, Mastercard, or American and Horticulturist Express. Send orders, remittances, requests to purchase back issues, change-of-address notices, David Yih and all other subscription-related communica- tions to Circulation Manager, Arnoldia, Arnold 37 Book Review: Knowing Nature: Art and Arboretum, 125 Arborway, Boston, MA 02130- Science in Philadelphia, 1740–1840 3500. Telephone 617.524.1718; fax 617.524.1418; Peter Del Tredici e-mail [email protected] 40 Betula dahurica: A Special Birch Tree Arnold Arboretum members receive a subscrip- tion to Arnoldia as a membership benefit. To Hugh McAllister become a member or receive more information, please call Wendy Krauss at 617.384.5766 or Front and back covers: On page 11, curatorial col- email [email protected] leagues Michael Dosmann and Tony Aiello continue their “Quest” series, this time searching for hardy Postmaster: Send address changes to southern live oak (Quercus virginiana). Photo of an Arnoldia Circulation Manager impressive specimen of southern live oak growing in The Arnold Arboretum Lake Kissimmee State Park, Florida, courtesy of David 125 Arborway Price, Bok Tower Gardens. Boston, MA 02130–3500 Nancy Rose, Editor Inside front cover: Blue flag iris (Iris versicolor) is one Andy Winther, Designer of many species recorded in a recent floristic survey of the Middlesex Fells, a unique nature preserve within Editorial Committee the Boston metropolitan area. Photo by Nancy Rose. Phyllis Andersen Peter Del Tredici Inside back cover: This Arboretum specimen of Dahu- Michael S. Dosmann rian birch (Betula dahurica, accession 1015-80-A) is of William (Ned) Friedman interest for its ornamental traits and its conservation Kanchi N. Gandhi value. Photo by Nancy Rose. Copyright © 2013. The President and Fellows of Harvard College The Middlesex Fells, a Flourishing Urban Forest Walter Kittredge … five miles northerly of Boston lies a great tract of country, all stony hills and tablelands, almost uninhabited, and of wonderful picturesqueness, and wild, rugged beauty … The nature of this region cannot better be characterized than by the application of the old Saxon designation fells,—a common enough word in England, meaning a tract of wild stone hills … Sylvester Baxter, Boston Herald Supplement, December 6, 1879 he Middlesex Fells is a forest of 3,400 acres just north of Boston, ITTREDGE Tthree-quarters of which is under the K jurisdiction of the Massachusetts Depart- alter ment of Conservation and Recreation. It W is one of four reservations that comprised the original Metropolitan Park System (MPS), the others being Beaver Brook, Stony Brook, and the Blue Hills. At almost eleven square miles, the MPS is one of the largest urban forest reservation systems in the world, only slightly smaller than the largest one in Rio de Janeiro. The reservations were set aside begin- ning in 1894, after a long and determined conservation effort by many prominent area residents. This noteworthy group included Elizur Wright, who reformed the life insurance business, fern expert George Davenport, naturalist Wilson Flagg, jour- nalist Sylvester Baxter, and renowned landscape architects Frederick Olmsted and Charles Eliot. They were aided in this effort by the Appalachian Mountain Club and the newly formed Trustees of Public Reservations. Their conviction that urban people needed a nearby reprieve from the city helped bring about this first-of- its-kind wild urban forest park system. Although Boston’s Emerald Necklace (which includes the Arnold Arboretum and Franklin Park) preceded the advent Bitternut hickory (Carya cordiformis) is fairly common in the Fells; of the MPS, the Emerald Necklace green this is the largest one at 32 inches (81.3 centimeters) DBH. It occurs in spaces differed from the MPS in being the newly designated Sugar Maple–Oak–Hickory Forest. Middlesex Fells 3 Y IBRAR L UBLIC P OSTON B THE at ENTER C AP M EVENTHAL B. L ORMAN N Middlesex Fells map from 1905. intentionally cultivated landscapes. As Elizur’s A TRACT OF WILD STONY HILLS daughter Ellen wrote, “What we wanted in the The Fells is a dissected upland with narrow Fells was a bit of nature so conveniently in our north–south ridges and valleys. The highest midst that we might watch its workings … we elevation is Bear Hill at 317 feet (96.6 meters) wanted dark crowded places, even jungles … above sea level, and the lowest is 65 feet (19.8 marshes into which one might wade after reeds meters), where Whitmore Brook exits the and bright berries, brooks where the border Fells. The volcanic bedrock is part of the Ava- growth and waters frolic together …” lon Terrane, an ancient Pangaean island chain 4 Arnoldia 70/3 • February 2013 ITTREDGE K alter W Pink lady’s-slipper (Cypripedium acaule) flowers and fruits prolifically after fires, taking advantage of the extra sunlight and extra nutrients from the ash. that collided with coastal New England and striations on the exposed bedrock, and the thin, Canada. The resulting geological features are stony glacial till soils. These poor soils, along a complex of felsic lava hills (including Pine with the steep topography, made farming so Hill) in the south, and plutonic domes of granite difficult that few people made their home there. (including Bear Hill) in the north. The middle The main use of the Fells was for timber and section of the Fells differs in having an overlay firewood, resulting in its forests having been of metasedimentary rock. The southeast corner cut over many times by 1894. It is noteworthy features a steep scarp along the North Bound- that despite this, there are areas that have many ary Fault, with panoramic views of the Boston trees over 3 feet (0.9 meter) DBH (diameter at Basin. One of the more intriguing geological breast height), the largest one being a red oak features is the Medford Dike, a narrow valley of (Quercus rubra) at Bellevue Pond with a DBH dark, mafic rock between Pine and Little Pine of 4.8 feet (1.5 meters). Hills, and the site of nineteenth-century quar- About one quarter of the Fells is water, mainly ries. The gritty gabbro rock from the quarries is in the form of reservoirs, which provide drink- called grus, and was used to line the paths of the ing water for the surrounding communities. Public Garden in Boston. There are also swarms The largest is Spot Pond, a glacial kettle pond of dark black Jurassic dikes, some of which can of 294 acres, so named in 1631 by Governor be seen in the cut side of Pine Hill along Inter- Winthrop for its many small islands. This, and state 93. Evidence of the glacial epochs remains several other open and covered reservoirs, are in the form of numerous large erratic boulders, operated by the Massachusetts Water Resources Middlesex Fells 5 AN RY Authority. The three reservoirs on IKE the western side of the Fells were M created out of the large Turkey Swamp before the reservation was set aside, and are owned (along with the adjacent land) by the town of Winchester. All of these reservoirs were included in both the original floristic survey of 1894–1895 and our recent 2003–2011 survey headed by Bryan Hamlin. Most streams in the Fells are small, but Spot Pond Brook had enough drop in elevation to provide water power for many small-scale industries. The Fells falls within the Mystic River watershed, which makes up over half of the Bos- ton Basin Ecoregion. This ecoregion includes the city of Boston, and has had 80% of its land developed. The Fells and Lynn Woods represent the only large blocks of native forest left in this ecoregion, forming isolated islands of natural vegetation in a densely populated area. The climate is in USDA Plant Har- diness Zone 6a (average annual mini- mum temperature -5 to -10°F [-20.6 to -23.3°C]), with average annual precipitation around 41 inches (104 centimeters). Climate change is evidenced by increasing tempera- tures in the Northeast; the Boston Ridgetop Pitch Pine–Scrub Oak communities are a very common prioirity area has been warming at a rate of habitat on rocky summits, especially in the southern portion of the Fells. 0.5°F each decade since 1970, which has significantly extended the growing season. A STORIed HIstORY OF BOtaNIZING Photographic records made during the nine The Middlesex Fells provides a forest panorama years of this survey support this, document- of changing seasons for the thousands of Boston ing increasingly earlier bloom times. Average area commuters who drive through it on either annual precipitation in the Northeast increased Interstate 93 or State Route 28 (the old Ando- 8% in the twentieth century, mainly occur- ver Turnpike), both of which bisect it. It was on ring in the last forty years. The proximity of the latter road that William Boott arrived in the Interstate 93 and the densely populated sur- 1850s to stay at a hotel on the south end of Spot rounding towns contribute to local air pollu- Pond and become the first to botanize the area.