This is the third installment in a series that opened with Charles Sprague Sargent’s monumental “The First Fifty Years of the Arnold Arboretum.” Richard Howard and Donald Wyman shared focused assessments at the Arnold’s centennial.

Round the bend on Hemlock Hill Road and look across Bussey Brook and Kent Field to the north. Your eyes will skim a patchwork of conifer textures, colors, and forms. Among the trees is an upright individual with a rather abrupt taper at the top, the Arnold Arboretum’s largest giant sequoia (Sequoiadendron giganteum, accession 1320-72*A), now standing eighty-three feet tall. After crossing the brook and walking up the slope, you’ll see that the wide bole (almost five feet in diameter) begs to be hugged. Shift your gaze up along the orange bark to the sky, and you’ll see the tree’s candelabra-like branching pattern. Most of the branches seem normal, erupting out of the main stem at right angles, but if you step back and keep your eye on the crown, you’ll see an odd conglomeration where one branch over another attempted to bend skyward.

Back in 1948 (the same year that Metasequoia glyptostroboides, the dawn redwood, arrived in North America), a supporter of the Arboretum, Chandler Hovey, collected giant sequoia seedlings from California and planted several near his home in Brookline, Massachusetts, a stone’s throw from the Boston College campus. In 1972, in honor of the Arboretum’s centennial, Boston College—which had recently acquired the Hovey property—donated the tree. That spring, a twenty-four-year-old, forty-two-foot-tall, pointy-topped tree was dug, transported, and transplanted in its current spot in the conifer collection.The magnificent specimen survived, but its central leader died due to transplant shock, leaving an oval-shaped form for decades. A new leader eventually took over: a dog-legged branch that formed fifty years ago from the initial crown’s tip, some forty-three feet above the ground. I’m certain that the wooden rings within that branch would reveal not just what was going on with that single tree but the surrounding Arboretum landscape as well.

A forty-two-foot-tall giant sequoia moves to the Arnold in 1972. Photograph from Arnold Arboretum Archives

The First Fifty Years

Just as the sequoia’s history is written within its rings, branches, and form, the Arboretum’s landscape and collections reflect a history rich in dramatic events and subtle ripples. Much has been written about them, and Charles Sprague Sargent’s “The First Fifty Years of the Arnold Arboretum” describes the first five decades with aplomb. At the time of Sargent’s writing in 1922, Harvard’s tree museum (founded in 1872) had expanded from 125 to 250 acres. Frederick Law Olmsted had reimagined Benjamin Bussey’s farm with carriageways and pathways, collection areas and viewsheds. Sargent and his team transformed the landscape into a composite of taxonomic tree groups and research plantings, including an intensely cultivated shrub and vine collection, all nestled among a few natural and naturalized woodlands.

By 1922, botanical exploration—particularly of East Asia and North America—and horticultural exchange yielded a living collection of over five thousand taxa growing at the Arboretum. The institution was well on its way to meeting its initial charge (a nascent collections policy, if you will) to cultivate every tree, shrub, and vine hardy in Boston. While many of the plants were botanical taxa, including wild-origin species newly cultivated in North America, there was no shortage of infraspecific forms and varieties that we would now call cultivars. The herbarium of two hundred thousand sheets complemented a thirty-five-thousand-volume library and archival collection of nearly ten thousand photographs. With these integrated living, preserved, and archival collections, the Arnold Arboretum had become an international destination for scholars of woody plants.

Yet Harvard’s tree museum was not just for the botanical connoisseur. This gem in Boston’s Emerald Necklace of parks provided open space to an expanding and diversifying city. Because of the 1882 arrangement where ownership of the land shifted from Harvard to the City of Boston (who then leased the property back to the university for at least one thousand years), the space would be secured in perpetuity as both a scientific enterprise and public open space, free for all to enjoy. Without this arrangement some 140 years ago, I doubt if the Arnold Arboretum would exist today, or if it did, if we would recognize it in its current form. Had it remained a nonpublic, university-owned research station, I can imagine acres by the dozen being peeled away and sold with each-and-every economic crisis. If purely a municipal park, even if well maintained, it would not house one of Earth’s most notable collections of woody plants. Luckily, these are just what-if scenarios.

Perhaps knowing his grip upon the Arboretum’s helm would not last much longer (though it did, for another four years), Sargent ended his half-century assessment with a few bold charges for his successors. Global environmental change was apparent to him, particularly the challenges to trees and forests worldwide. Thus, Sargent called for continued and ambitious documentation of forests in Asia and the tropics, as well as rigorous scholarship in forest pathology, entomology, and genetics. Within the Arboretum landscape, Sargent felt that a rose and a rock garden would be essential additions, no doubt to provide space for new collections development while simultaneously enhancing the horticultural display. Despite the growth of the initial Arboretum endowment from $103,847 to $808,175, Sargent knew that additional resources would be required not just for these new initiatives but to maintain current operations. Thus, he curtly ended his fifty-year report with one sentence: “Only a larger endowment is needed to make possible these Arboretum activities and extensions.” Following his death in 1927, the Sargent Memorial Fund would raise over a million dollars.

The space would be secured in perpetuity as both a scientific enterprise and public open space, free for all to enjoy.

The Second Fifty Years

The Arboretum’s second half-century was dramatic and dynamic. The institution weathered a global economic depression, multiple leadership changes (one supervisor and three directors), the catastrophic hurricane of 1938, as well as another World War. There was also the Controversy (as it was referred to), which amalgamated the university’s herbarium and botanical library collections (including most of the Arboretum’s) under one roof in Cambridge. This coincided with the cessation of the Bussey Institution, which had opened as Harvard’s center for horticultural and agricultural education in 1871, on property adjacent to the Arboretum. The institute grew into a center for genetic and cellular research. By the 1930s, most of the on-site scholarship in the Arboretum’s living collections had waned. Likewise, the Arboretum’s fieldwork in temperate areas, particularly to acquire germplasm to grow in the living collections, ceased almost entirely. However, botanical exchange of seeds persisted, with the 1948 acquisition of the Chinese dawn redwood, Metasequoia glyptostroboides, being one of the most celebrated feats even to this day.

The discipline of horticulture—often considered the art and the science of growing plants—matured in the mid-twentieth century. The genetic improvement of ornamentals hit a stride, as did advanced ways to propagate them clonally. As a result, cultivars (first given formal recognition in 1952) wantonly tumbled out of nursery catalogues and into gardens, parks, and other managed landscapes. The Arboretum’s living collection was no exception.

In 1970, Donald Wyman, horticulturist in charge of the Arboretum from 1935 to 1970, wrote in these pages about the Arboretum’s goal to improve the curation and care of the collections, and to use the collections as a living laboratory for horticultural introductions. Species plucked from the wilds in the Arboretum’s first half-century would be assessed for their garden worthiness in the second. Novel hybrids, like crabapples (Malus) and forsythia (Forsythia) created by Karl Sax (a professor who then served as director from 1947 to 1954), were given growing space, with many introduced as cultivars after evaluation. Arboretum selections, and those from sister institutions and industry, were grown side-by-side, their performance recorded in Arnoldia and other publications.

Just like there were changes to what the Arboretum grew in the collections and why, there were changes to where they were grown. The 1942 acquisition of the Case Estates in Weston, Massachusetts, provided a welcome relief valve for the space-cramped Boston collection. Shortly thereafter, several ornamental collections in Boston underwent redesigns: Landscape architect Beatrix Farrand’s Azalea Border along Meadow Road added dramatic color and space for the deciduous Rhododendron that were performing poorly elsewhere. Crabapples, the dandy of mid- to late-twentieth-century landscapes, replaced most of the hawthorns (Crataegus) on Peters Hill during renovations from 1948 to 1952. The construction of the Dana Greenhouses in 1962 provided a sophisticated station where propagator Alfred Fordham could conduct his many experiments and publish them widely.

Collections of the Third Fifty Years

The centennial in 1972 arrived with fanfare and excitement. Dick Howard, director since 1954, began his 1971 annual report to the Harvard University Provost by underscoring the Arnold Arboretum’s essential service role to the City of Boston, particularly to local communities. Maintaining the Arboretum required considerable resources that were worth the expense and investment, and caring for the collections was his “priority responsibility.” Thus, irrigation projects in both Boston and Weston would alleviate some of the growing and unmet demands for water. A bucket truck was added to the fleet, which made pruning or removing old, senescing “stag-headed” trees easier. To replace some of the removals, horticulturists planted out nearly nine hundred specimens, completing a cycle of rejuvenation and renewal. Anticipating future databasing, Howard noted that the plant records office had wrapped up a major inventory campaign to assess and field-check every specimen in the collection.

Over the Arboretum’s third fifty years, the institution would be led by four directors: Richard Howard’s tenure ended in 1978; Peter Ashton led from 1978 to 1987; Robert Cook from 1989 to 2009; and William (Ned) Friedman became director in 2011. During this time, the Arboretum experienced dramatic changes, as did the living collections. Staff actively contemplated what to cultivate, where to grow it, and how to do it better.

Major anniversaries like a centennial can elicit reflections and ambitions, so it is no surprise that shortly after Peter Ashton became the director in 1978, strategic planning was underway. One broad initiative, a restoration plan, included a substantial section for what should be in the collections. A formal living collections policy—the first for this Arboretum and most botanic gardens—was also published in 1979, remaining in force for almost thirty years. In this latter document, the Arboretum established and codified ambitious goals: to acquire all known woody species hardy in Boston (no different from the original charge of 1872); to have three individuals of each species; to prioritize wild-provenance plants above those of garden or nursery origin; and (assuming they met specific requirements) to continue to maintain taxa at infraspecific ranks (including cultivars, although these were considered lowest in any hierarchy).

To complete the collections, the 1979 restoration plan outlined the addition of over 2,900 taxa, spanning 90 families and 363 genera. These desiderata came almost exclusively from identifying which plants in the 1940 edition of Alfred Rehder’s Manual of Cultivated Trees and Shrubs Hardy in North America were missing from the collection. To launch the initiative, staff set an ambitious goal of acquiring 1,500 taxa in the first five years.

The layered naturalism of the Arnold Arboretum arises from generations of horticultural stewardship and curation. Photograph by Jonathan Damery

Even before strategic planning of what to add, the Arboretum reconsidered where new material would come from and how to acquire it: collectors would return to the field. In 1977, the Arboretum embarked on its first major collecting trip in some forty years, sending taxonomists Stephen Spongberg and Richard Weaver to South Korea and Japan for six weeks. In 1980, following the heels of the restoration plan, Weaver botanized in the Soviet Union, while Spongberg participated in the three-month-long Sino-American Botanical Expedition, which involved a team of thirteen Chinese and American collaborators. (China had not been visited by Western botanists since before the revolution in 1949.) The era of fieldwork had returned.

Through the 1980s and early 1990s, the infusion of wild-collected material from some seventeen expeditions occurred at a scale not seen in fifty years. In some years, the Arboretum sponsored multiple collecting trips. Destinations included those known to yield hardy material such as northwestern Hubei Province, China, and the Appalachian Mountains of the American Southeast, as well as fringe regions like North Africa, Mexico, and Taiwan. Coincident with fieldwork, the Arboretum also received new material from sister institutions, often selected from their annual seed lists (known as index semina).

Through the 1980s and early 1990s, the infusion of wild-collected material from some seventeen expeditions occurred at a scale not seen in fifty years.

Although the restoration plan advised against “returning to what must have been almost a jungle by the end of Sargent’s tenure as Director,” there was no discussion as to where some five thousand new plants (an increase by approximately 30 percent) would be sited in the collections. Thus, limitations in capacity and resources—facilities, staffing, and space—hindered the restoration’s full success. For one, the Arboretum lacked the facilities to propagate and produce the sheer magnitude of material arriving in such a short period. The plant records database is replete with notations from index cards of whole flats of accessions that perished due to the lack of production space (many were placed in the shade below the benches). Gary Koller, Wyman’s successor as the lead horticulturist, has told me how, due to severe space constraints in the collection in the 1980s, sibling plants of the same accession were planted together in tight triads, about five feet apart. Only a few of the triads remain today, primarily sited along the roads and perimeter of Bussey Hill. Deaccessioning plants was taboo, so there were few other alternatives. The 1979 restoration document was successful as an acquisitions plan yet perhaps too ambitious given practical considerations.

Hao Riming of the Nanjing Botanical Garden (left) and Peter Del Tredici were among the team on a 1994 expedition to Hubei, China. Photograph by Paul Meyer,
Hiroshima University’s Katsuhiko Kondo (left) assisted Stephen Spongberg and Richard Weaver in Hokkaido, Japan, in 1977. Photograph from Arnold Arboretum Archives
David Boufford photographed members of the 1984 Sino-American Botanical Expedition to Yunnan, China, as they prepared to embark into the field. Photograph from Arnold Arboretum Archives

A decade later, following changes in Arboretum leadership (Robert Cook became director in 1989), a Living Collections Long-Range Planning Committee returned to the process of thinking about the collections. In 1991, the committee completed a planning document, edited by Stephen Spongberg, which acknowledged that the 1979 restoration may have been naïve. The committee noted the challenges in adopting a comprehensive collection (meaning one of every taxon) versus a synoptic or broadly representative collection. They observed that it would be difficult to preserve the integrity of the Arboretum’s historic landscape in light of the aggressive drive to acquire new material. Nevertheless, the plan ended with a reaffirmation of the same ambitious collection policy goals articulated in 1979.

To accommodate this expansion while remaining sensitive to the Olmsted design (by not transforming the collections into a dense forestry plantation), the 1991 plan called for the prudent review and deaccessioning of low-value and out-of-sequence material. The authors proposed a long-term review process that would finally deal with many of the growing pains that had affected the Arboretum since (and perhaps prior to) the death of Sargent. Although there were no estimates of how many plants could be deaccessioned, the authors stated that such subtractions would be insufficient to accommodate the necessary expansion. The 1991 plan estimated that all Arboretum property must be designated for the purpose of housing an expanded collection, including the entirety of Peters Hill, Bussey Brook Meadow (formerly called the South Street Tract or Stony Brook Marsh), Weld Hill (formerly Weld-Walter Street Tract), and the Case Estates. Space was not the only resource required: the plan identified new staff positions necessary for curation, horticulture, and the greenhouse and nursery.

Shortly after the 1991 plan was completed, it was put on hold following a reorganization of the Arboretum’s administrative structure in early 1992. A new Living Collections Department was created, with Peter Del Tredici leading. The ambitious goal of the 1979 and 1991 plans to form a comprehensive collection was admittedly unrealistic and abandoned. Instead, as Del Tredici outlined in 1994, collections development would take a more focused or prioritized approach. During the early 1990s through the mid-2000s, special recognition was reserved for conservation-status species (particularly those maintained in collaboration with the Center for Plant Conservation). As a theme, the floras of eastern Asia and eastern North America were given priority, particularly genera like Acer (maples) and Fagus (beeches), which became two of the initial five collections nationally accredited through the Plant Collections Network. (The Arboretum now has eight accredited collections.) The recently established North America–China Plant Exploration Consortium (NACPEC) became a pipeline for novel germplasm from China. From 1991 to 2006, the Arboretum mounted six expeditions to China, two under the NACPEC flag, including the 1994 expedition to Hubei that infused the collections with new material like the paperbark maple (Acer griseum), which had most recently been collected by Ernest Henry Wilson in 1907.

Within a year of joining the staff in 2007, I organized a team to update collections goals and codify them in a new living collections policy. The scope of the collections would remain synoptic, with the highest priority assigned to core collections, such as the nationally accredited collections and conservation-status holdings. Historic lineages would be maintained through repropagation, while targeted acquisitions of cultivars would meet trialing, display, and research needs. The new policy (and its subtle revisions over the past fifteen years) prompted the review and subsequent deaccessioning of excessive or low-value accessions, as well as the repropagation of valuable lineages that had gone unnoticed.

Fieldwork continued, with another six expeditions occurring between 2007 and 2015, including a NACPEC expedition to the Qinling Mountains of China in 2010 and a more focused collecting of live oak (Quercus virginiana) from the northeastern edge of its range in Virginia in 2012. In 2015, the Arboretum launched the Campaign for the Living Collections, an initiative that followed several years of planning from the Living Collections Advisory Board. The campaign articulated a list of nearly four hundred target taxa, each linked to one or more priority themes found in the collections policy. Since the campaign launched, some twenty expeditions—to destinations in the United States, China, Japan, and the country of Georgia—have yielded over half of the desiderata. The COVID-19 pandemic paused expeditionary work for 2020 and 2021.

While the Arboretum embarked on exactly fifty named expeditions over the past fifty years, plants of cultivated origin were added to the collections (or maintained) for their invaluable ornamental characteristics, stress tolerance, and other novel traits valued in managed landscapes. Cultivars of trees continued to grow alongside their wild-origin brethren particularly in the Rosaceous orchards of Peters Hill—while new shrub cultivars appeared in the Bradley Rosaceous Collection (dedicated in 1985), the Leventritt Shrub and Vine Garden (dedicated in 2002), and other landscapes. In 1972, 14,058 plants grew in the Arboretum’s collections in Boston, and only 14 percent were of wild origin. As of this writing, 44 percent of the 15,939 plants in the collections were derived from wild populations, and if one excludes over 2,700 accessioned plants in the natural areas (such as Hemlock Hill, which is a mix of wild and planted hemlocks), 53 percent of the collections are from the wild. That is quite the illustration of focused and deliberate collections development.

Designing the Collections

Perhaps the most significant outcome from the 1979 restoration plan was the recognition of historical planting areas, as articulated loosely using the Bentham and Hooker linear sequence. Richard Weaver created maps for each family and major genus, using red colored pencil to illustrate where new plantings should go (or, in some cases, errant shrubs should be returned). This reordering was meant to fix what were perceived as random horticultural plantings, particularly those from the mid-twentieth century.

All gardens need redefinition from time to time, and many areas within the Arboretum received edits over the past fifty years. For instance, Rhodie Dell—the collection of broadleaved Rhododendron along Bussey Brook at the base of Hemlock Hill—was renovated in 1990 with the Davison Path laid out by Julie Moir Messervy. The landscape around the Hunnewell Visitor Center received a new look by Carol Johnson after the building was renovated in 1993. In 2007, Beatrix Farrand’s Azalea Border along Meadow Road received an infusion of new material following the removal of declining individuals.

One of the major goals Sargent described in 1922 was the creation of a rose garden, and in 1985 the Arboretum made good on this promise. A gift by Eleanor Cabot Bradley and an innovative design by Gary Koller created the Bradley Rosaceous Collection. Located near the ponds and replacing the existing shrub collection (where many of the Rosaceous shrubs grew already), this semi-formal garden adjacent the Forest Hills Gate became and continues to be a public gathering space and programming site. Updates completed in 2011 (by Julie Moir Messervy) improved circulation and display potential, and two wrought-iron arbors designed by Peter Andruchow added spaces for climbing roses.

While the Bradley created a significant destination for visitors, the diaspora of shrubs and vines from the earlier shrub garden led to a problem. Many of the vines were moved to chain-link fences on the perimeter, becoming challenges to maintain, while sun-requiring shrubs—now grown in the shade under their arboreal cousins—did not always fare well. To ameliorate this dilemma, the Arboretum needed a new shrub and vine collection, and with a gift from Frances Leventritt, the Victor M. and Frances Leventritt Shrub and Vine Garden was created in 2002. Designed by Reed Hilderbrand, this formal garden would house sun-loving shrubs and vines on property to the north of the Dana Greenhouses, on space previously occupied by the old hedge and dwarf conifer collection. Unlike other areas of the Arboretum’s collections, the shrubs and vines grown here were to receive intense horticultural care and inspire ideas for home landscapes.

The Leventritt Shrub and Vine Garden is one of two showcase gardens built during the Arnold’s third fifty years. Photograph by Jon Hetman

Peters Hill, often neglected due to a lack of resources and its distance from the hub of operations, began to receive attention starting with a curatorial review in 1993. Low-value plants were deaccessioned; new plantings (particularly crabapples and deciduous gymnosperms) followed; and a bus turnaround at the summit was removed and renovated to support plant collections in 1997. Another major change occurred in 1996 when the South Street Tract was combined with land owned by the Massachusetts Bay Transportation Authority and the City of Boston, creating what is now known as the Bussey Brook Meadow, a twenty-six-acre urban wild with the Blackwell Path connecting Forest Hills Station to the South Street Gate.

All gardens need redefinition from time to time, and many areas within the Arboretum received edits over the past fifty years.

Stewarding the Collections

In his 1971 report, Richard Howard noted that his highest priority was the maintenance of the living collections. His successors possessed the same agenda, mustering resources to support them as creativity and windfall allowed. Over time, work at the Case Estates waned to the point that by 1991 the horticultural staff in Weston shifted permanently to care for the collections in Boston. (The final sale of the Case Estates occurred in 2017.) Ongoing growth in the Arboretum’s endowment, particularly during the capital campaign ending in 2000, allowed further staffing increases, and restricted endowments for areas like the Bradley Rosaceous Collection and the Leventritt Shrub and Vine Garden funded exclusive and dedicated horticulturists to care for each high-maintenance area.

Another major shift in resourcing occurred with the launch of the Landscape Management Plan in 2008, a charge led by Richard Schulhof (the deputy director) and implemented by Stephen Schneider (then the manager of horticulture). Recognizing the value of having already designated horticulturists in several areas, such as the Shrub and Vine Garden, the Landscape Management Plan expanded the perspective to all areas of the Arboretum landscape. The landscape was divided into zones, with individual horticulturists assigned to steward each according to goals specific to each area. The plan also directed the work of arborists as they rotated through the collections, and landscape staff as they maintained meadows, turf, and pathways.

In addition to performing the day-to-day care of the collections, horticulturists must contend with periodic natural disasters, pests, and diseases. Though not as cataclysmic as that infamous and unnamed hurricane that struck in 1938 (which destroyed some fifteen hundred trees), the 1997 April Fool’s Day storm dumped over two and a half feet of snow on a collection previously plagued by past droughts. Over four hundred trees had to be removed that season, while another thirteen hundred remained but required arboricultural care. Pathogens and pests are a persistent threat to the collections. For instance, in the 1980s and 1990s, phytoplasmas plagued the lilac (Syringa) collection, and in 1997, hemlock woolly adelgid arrived at the Arboretum’s doorstep to forever change the face of Hemlock Hill, a unique natural landscape where black birch (Betula lenta) are slowly replacing the hemlocks (Tsuga). And, in 2018, many old beeches (Fagus) were removed due to decline caused by the arrival of beech bark disease. All three of these collections—the lilacs, hemlocks, and beeches— are nationally accredited, so their stewardship in response to these outbreaks is especially significant. The Landscape Management Plan includes response plans for disaster and plant healthcare issues like these.

In late 2019, Andrew Gapinski, as manager of horticulture, transformed the third edition of the Landscape Management Plan into a dynamic, digital format known as the Landscape Management System. As part of the system, a smartphone and desktop application called ArbManager replaced the paper forms (the “green cards”) exchanged between horticultural and curatorial staff to communicate about work requests, while an internal website, ArbDashboard, synthesized horticultural and plant records data into a map-based system. Both of these tools provide living collections staff instant access to collections-care directives, whether they are in an office or fifty feet up a tree and accessing the information from a phone.

Recording the Collections

The Arboretum is replete with uniquely accessioned plants, each richly documented with source histories, observations, photographs, herbarium specimens, and maps—a tradition dating back to the institution’s founding. In Howard’s 1972 annual report, he noted how the card catalog entries—the original paper database for the living collections, if you will—were incorporated into the Plant Records Center of the American Horticultural Society. This initial digitization effort was championed by Howard when he was president of the American Association of Botanical Gardens and Arboreta. The shared database gave gardens the chance to store computerized records off-site (as a preservation initiative) and recall specialized lists of plants on demand (for instance, all plants in a given location within a garden).

In 1985, the Arboretum’s plant records and systems (including definitions, workflows, and philosophies) seeded a new database eventually called BG-BASE. The Arboretum now had local access to its data, which revolutionized how the Arboretum and finally other gardens curated their collections. At first, the database only included living plants; however, funding from the Institute of Museum and Library Services (IMLS) in 2010 allowed staff to integrate legacy data from old index cards into BG-BASE, providing access to historic collections that had long ago perished. An earlier IMLS grant, in 2001, enabled the digitization of records for some fifty thousand vouchers from the herbarium of cultivated plants, adding even more data and research value to plants that grow or grew in the living collections.

Hand-drawn maps had recorded the locations of plants growing in the collections since 1938, and in 1987, cartography went digital due to support from IMLS. Initially, AutoCAD served as the digital platform; however, in 2010, the platform shifted into ESRI ArcGIS, a more robust geographic information system. This change was timely, as the IMLS grant in 2010 also allowed for the scanning and georeferencing of some two thousand hand-drawn maps, providing staff the ability to view—like a digital flip-book—the historic collections over time. Coincident with the legacy of mapping has been the annual inventory process, whereby all accessioned plants are field-checked on a five-year cycle. Whereas earlier field observations required paper cards, notebooks, and copies of maps, the current team led by Kyle Port, the manager of plant records, employs live connections to the database in the field using laptops and tablet computers. I wonder what Professor Sargent would think if he could witness such activities in action!

While countless other initiatives over the past fifty years led to curatorial reviews and data acquisition, one final, and significant, venture was a multiyear verification project funded by the National Science Foundation in 1984. This project led to the vouchering (using herbarium specimens) of the living collections. The vouchers were then distributed to taxonomic specialists around the world who verified the identity of each plant. The effort yielded positive (as well as negative) identifications and fostered international research interest in the living collections.

Using the Collections

While this article mostly reflects the living collections and their change over time, to leave out access and use would be a grave mistake. The Arboretum is not a private collection but is, in fact, very public. Due to the porous nature of the Arboretum, visitor counts have always been a rough guess. Until recently, estimates of annual visitors were in the “hundreds of thousands,” which at the time may have been accurate. However, a people counter at the popular Arborway Gate—one of more than a dozen entrances—tallied some 825,000 hits from September 2020 to September 2021. This number includes ins-and-outs as well as pass-throughs, yet even with a conservative estimate of half this total (equal in and out hits) of 400,000 visitors at this single gate, it is safe to assume that well over a million people, and perhaps over twice that number, visit the Arboretum each year.

After the Bussey Institution ceased to exist and much of the herbarium and library migrated to Cambridge, it had become more difficult for the living collections to readily serve scholars. However, engaging scholars to use the living collections has long been an area of interest of mine, even before joining the staff, and was one of the reasons I was hired into this role fifteen years ago. Luckily, much work had been initiated before my arrival. Five decades of field exploration yielded a collection rich in botanical diversity and wild provenance: research specimens little different from what a scholar could find in the natural environment. Year-over-year improvements in horticultural care provided healthier plants available for study. Ongoing vouchering, verification, and inventory initiatives add rich documentation to the plant records, all of which have been searchable online for over two decades.

Meadow Road, a winding Arnold thoroughfare, welcomes at least half a million visitors each year. Photograph by Jonathan Damery

Funding also helped bring scholars to the collections. In 1988, initial support (and later an endowment) provided by George and Nancy Putnam created the Putnam Fellowship specifically for those conducting independent research and project work using the collections. These and other competitive awards have helped to remove financial barriers that might otherwise prevent research from occurring.

Lastly, in 2011, the Weld Hill research facility opened. While it was initiated and built during the administration of Bob Cook and opened and staffed shortly after Ned Friedman became director, the facility was inspired by Peter Ashton, who attempted to reinstall scholarship within the Arboretum landscape during his tenure. Now, after some seventy-five years since the Bussey Institution closed, research and its requisite facilities are unified with the Arboretum’s living collections. As a result, visiting scholars from all over the world can work in state-of-the-art laboratories just footsteps from the living collections. Shortly after I began my work at the Arboretum, about a dozen projects occurred in the collections each year. Currently, some seventy-five to one hundred projects use the living collections, landscapes, and environments annually.

The Fourth Fifty Years

The year 2072 seems so far off. I doubt that I’ll be above ground, or if I am, how well I will be able to peruse the collections as they celebrate their bicentennial. Still, if I am around at that time, just a few years shy of my own centennial year, I would like to see the trees from the 1977 expedition to Korea and Japan spreading their branches among the overstory of the collection. I would like to see plants from the Campaign for the Living Collections: some of those trees have recently been released from the nursery and are already taller than me. I’m confident that many will have become standouts—the masterpieces of a new generation—and subjects of research that we would find impossible to imagine in 2022.

And of course, I would also make my way over to the giant sequoia that overlooks Bussey Brook, checking in to see how it had fared. No doubt, it will have weathered droughts and blizzards, perhaps even a lightning strike due to its ever-increasing height. But I like to imagine it will still be standing, a silent sentry watching over Harvard’s tree museum.

Michael S. Dosmann is the keeper of the living collections at the Arnold Arboretum.

From “free” to “friend”…

Established in 1911 as the Bulletin of Popular Information, Arnoldia has long been a definitive forum for conversations about temperate woody plants and their landscapes. In 2022, we rolled out a new vision for the magazine as a vigorous forum for tales of plant exploration, behind-the-scenes glimpses of botanical research, and deep dives into the history of gardens, landscapes, and science. The new Arnoldia includes poetry, visual art, and literary essays, following the human imagination wherever it entangles with trees.

It takes resources to gather and nurture these new voices, and we depend on the support of our member-subscribers to make it possible. But membership means more: by becoming a member of the Arnold Arboretum, you help to keep our collection vibrant and our research and educational mission active. Through the pages of Arnoldia, you can take part in the life of this free-to-all landscape whether you live next door or an ocean away.

For more tree-entangled art, science, and writing, subscribe to Arnoldia by becoming a member of the Arnold Arboretum.