In this 1675 map, trees reveal the British crown's colonial interest in North American natural resources as profitable commodities. Created by John Seller, this map documents the boundaries of the Massachusetts charter of 1628. In the artist's rendering, trees of many shapes and sizes cover the landscape, showing a space that is abundant with both timber and animals (like beavers, rabbits, turkeys, and whales) that were lucrative for global trade. However, the commodification of natural resources put the colonists into conflict with a number of Indigenous tribes who inhabited and maintained the land long before Europeans arrived. In fact, Seller created this map during the first year of King Philip's War: a devastating conflict that erupted after decades of competing land claims between the English, the Wampanoags, and the Narrangasett. The conflict had many environmental factors, including settlers’ livestock destroying Native crops. In his book Changes in the Land: Indians, Colonists, and the Ecology of New England, William Cronon writes that the dispossession of Indigenous populations by Europeans “in New England was as much an ecological as a cultural revolution, and the human side of that revolution cannot be fully understood until it is embedded in the ecological one. Doing so requires a history, not only of human actors, conflicts, and economies, but of ecosystems as well.”

This 1723 map of Boston illustrates how a single tree became an important symbol of the Boston Common early in the city's history. At this point, the Common was primarily used for pragmatic reasons that included pastureland, a burial ground, and a military outpost. The map shows one singular tree standing in the center of the Common: likely the "Great Elm," which was already an important landscape marker among colonists, as it was one of the few large trees on the Common. The Great Elm, which likely dated to approximately 1670, is given the same stature on the map as the powder house, highlighting its notable size. In contrast, the seemingly empty landscape surrounding the tree emphasizes how the Common's use was still far more utilitarian than aesthetic, which made trees in general a less prioritized component of the landscape during this era.

This map, by French map maker Jean Lattré, provides insight about Boston’s international importance circa 1764. Lattré seems to have created the map during or shortly after the conclusion of the Seven Years’ War in 1763, which caused France to lose most of its colonial territory in North America. However, eager to recover its losses from the war and weaken Britain’s power, France continued to monitor colonial unrest in the Americas, including the radical and unruly Bostonians–who resisted aspects British imperial rule (such as the Stamp Act of 1765) by hanging effigies, raiding homes, and rioting in the streets. One decade later, the French became important allies of the American revolutionaries. In Lattré’s 1764 map (created for French authorities), the Common ("commune" in French) once again provides an important landmark for navigating the colonial city. However, the famous Liberty Tree ("Arbre de liberté") is mislabeled. The Liberty Tree stood at the present-day intersection of Washington Street and Essex Street. It seems that Lattré mistook the Liberty tree for the "Great Elm" that stood on the Boston Common until 1876. This map points to what can get lost in translation, and reminds us to view all sources with a critical eye and compare them to other historical documents for verification.

In this colonial era etching, the trees provide insight into a city on the brink of revolution. Although the scene appears tranquil and pastoral, art historian Margaretta Lovell describes it as simmering with "personal turmoil and public enmity." In 1768, the artist and sailor Christian Remick dedicated the original watercolor version of this painting to John Hancock, whose large house is visible in the top right portion of the image. Hancock was a prominent Bostonian and tax-protestor whose ship named Liberty had just been seized by British officials that same year. Now known for his prominent signature on the Declaration of Independence, the seizure of Hancock’s ship caused a riot, which led the British parliament to call for an increased number of troops in the city. In this image, one sees the troops stationed on the Common practicing military drills. On the outskirts of the Common, however, Remick painted a perimeter of trees where the everyday social lives of Bostonians still plays out amid the rising political tensions. Despite the militarized atmosphere, one can glimpse how Bostonians still used the land as they pleased, covered by the shade and relative privacy of the trees. We see a woman sitting in repose; a man eavesdropping on a couple; two men strolling with a dog; and a handful of clandestine lovers–all reminding us that life carries on, even in revolutionary times.

This scene subtly reveals the Common as a utilitarian landscape that was giving way to recreational uses. Drawn by James Kidder in 1829, the image documents the final year that cattle and sheep were allowed to graze on the Common. Families in genteel apparel stroll along the paths, while children chase after a dog. The trees in the center of the image also provide clues about this landscape transformation. In 1728 and 1734, the city of Boston planted a perimeter of trees along Tremont Street to form the shady walk known as the Mall. However, the Common still only had a handful of trees among its grassy expanses throughout most of the 18th century. In 1784, however, the mayor instructed the city to plant additional trees throughout the Common–which are seen here, still in their fairly young state with scaffolding to protect them. The city also leveled much of the ground and added walkways, which crisscrossed the Common by the 1830s. Meanwhile, the few remaining cows in the drawing are pushed to the periphery–a prescient sign of their numbered days on the Common.

Picturesque trees tower above a massive crowd in this 1848 commemorative lithograph. The vivid scene depicts a celebration of the arrival of the Cochituate Aqueduct’s waters, which flowed into the Common’s Frog Pond for the first time in 1848. In the background, a fountain spews a huge volume of water into the air as countless onlookers watch. Although this level of celebration for a park fountain can be hard to imagine today, the aqueduct was a massive infrastructural feat that marked a new era of public health in Boston. The construction of aqueducts provided Bostonians with a consistent source of fresh water supply for the first time, which dramatically decreased waterborne diseases by replacing unsanitary local drinking sources. Yet, while the fountain looms large in this image, the trees loom even larger, with their lush leaves filling half of the frame. The composition’s attention to both water and trees reflects urban residents’ growing attention to green spaces as significant sites of both recreation and public health.

Although New York City’s Central Park was historically referred to as “the lungs of the city,” the same description can be applied to the Boston Common. This 1850 lithograph provides a bird’s eye view of the Common and the Boston Public Garden (established in 1839). In this image by John Bachmann, the rapidly expanding city crowds these luxurious green expanses–which were becoming more important as urbanization and industrialization progressed. The crowded, indecipherable buildings of the city present a sharp contrast to the stark, neat, and vividly-colored arboreal lines of the Common and Garden. The aerial view highlights the perfect symmetry and spacing of the trees, which line the perimeters and walkways of both spaces. Despite the highly designed visual attributes of these green spaces that can make them seem purely ornamental, one can see how the Common and Garden also provided necessary “breathing room” for Bostonians during this era of urban expansion.

In 1876, a fierce winter storm toppled the iconic “Great Elm” of the Boston Common. According to scientific speculation at the time, the magnificent tree stood at the center of the Boston Common for at least two centuries before it fell. In 1825, its dimensions were recorded as 72.5 feet high, 22.5 feet in girth (one foot from the ground), with a canopy of 101 feet in diameter. By the mid-1800s, the massive tree garnered the nickname of “Boston’s oldest inhabitant.” Many Bostonians mythologized the Great Elm as a silent witness to human history. They believed that the elm existed before Boston’s founding in 1630, which allowed it to observe the city's entire history. Although this periodization is questionable (since the tree likely dated to 1670), landscape studies scholar Anne Beamish writes that indulging “the idea that this elm witnessed the extraordinary events of the city and the founding of the nation thrilled Bostonians. Poets and writers revelled in the tree’s ‘dumb witness’ to the past.” After the tree’s death, Robert Waterson even wrote a historical account from the tree’s perspective, titled “Story of the Old Elm on the Boston Common.” When the Great Elm fell in 1876, its demise happened to coincide with the United States’ centennial. For many Bostonians, this timing transformed the tree into not just an iconic symbol of Boston, but of the United States at large.

In 1910, the Boston Public Grounds Department compiled a scrapbook of photographs that documented and measured the trees of the Boston Common. That same year, the Olmsted Brothers firm conducted an inventory that indicated a total of 812 trees on the Common–which this scrapbook may have been part of. The “Boston Common Trees” photo album feels simultaneously scientific and sentimental. In each photograph, an unidentified man holds a number sign (to label the tree) and a measuring stick (to provide a sense of scale). Despite this somewhat sterile form of photographic documentation in this album, its location in a handmade scrapbook–a medium typically associated with portraits of family and friends–provides a sense of emotional care and connection to the trees. In some of the images, the man places his hand on the tree, as though he is posing with someone familiar. In other photos, park visitors also look into the camera and smile beside the tree, giving the impression of a group portrait. Despite the fact that the Boston Public Grounds Department created this album 115 years ago, humans continue to forge all kinds of connections with trees–ranging from scientific study to deeply personal associations.

In the 1940s, the City of Boston reintroduced plants and animals not seen on the Common since the 1820s. During World War II, the federal government encouraged citizens and municipalities to create their own “victory gardens” to counteract food shortages induced by the war. The gardens were also seen as potential sources of pride and inspiration. In a government publication titled “Garden for Victory: Guide for Planning the Local Victory Garden Program 1942,” gardens were lauded for their ability to “maintain and improve the morale and spiritual well-being of the individual, family, and Nation. The beautification of the home and community by gardening provides healthful physical exercise, recreation, [and] definite release from war stress and strain.” Boston park officials responded by reintroducing subsistence gardens to the Common. They also used horses to help till the soil, as seen in this photograph (despite the 1830 livestock ban). For a brief time, then, ornamental shade trees once again shared the Common with agricultural plants cultivated for subsistence. Although the Common returned to exclusively recreational use after the war, the Fenway Victory Gardens still remain in Boston as one of the country’s two known remaining World War II victory gardens.

Despite its pastoral appeal, political protests have been part of the Boston Common’s history since the 18th century, at least. Although it was not located on the Common, the famous Liberty Tree of the American Revolution also indicates that environmental landmarks have long been used to both locate and symbolize political struggles. The politicization of parks returned to the Common in 1970, when a large crowd of anti-war demonstrators gathered there. The group consisted of thousands of college students protesting the murder of four college students at Kent State (who were shot by members of the Ohio National Guard), as well as U.S. military actions in Vietnam. If you look closely in the background of the photograph, you can see how protestors used trees as tools of political dissent. Some hung anti-war messages from trees (“My Lai / Kent State / Politicians are Murderers”), while others sat high atop the branches to further dramatize their defiance.

As the twentieth century progressed, Boston’s dense urban environment put increasing environmental stressors on the Common’s trees. Underground transportation tunnels, heavy foot traffic, and industrial pollutants all take their toll on the city trees. In 1983, the Parks and Recreation Department published construction and improvement plans for Boston Common, one page of which is featured here. The illustration provides a tree-planting guide–complete with steel cables and anchors to keep the tree upright, and specific instructions for mulch depth. The practical guide reveals how much maintenance goes into sustaining the life of a single Boston Common Tree—which illuminates the ongoing time, labor, and financial resources it takes to care for the hundreds of trees that still populate the Common today.

Across the United States, many cities experienced a decline in urban infrastructure investments that largely began in the 1970s. By the late 1980s, the City of Boston made plans to counteract this trend by improving the Midtown area adjacent to the Common. The plan called for more focal points, public plazas, and streetscape improvements. Notably, the plan called for “extending the beauty of greenery and the liveliness of public events [from the Boston Common] into the Cultural District.” Developers hoped to “make the southern edge of Boston Common an outdoor extension of the Cultural District.” They also called for “reactivating” the Liberty Tree Corner through redesigning its small park. Both the Common’s trees and street trees are vividly colored on the map as central components of this Midtown revitalization. While the Common was still celebrated as an exceptional green space, this map reflects a growing desire to also develop and maintain "urban nature" beyond the boundaries of the park.

Every thirty minutes, a camera affixed to the roof of the ten-story Walker building (owned by Emerson College) takes a photo of part of the Boston Common’s tree canopy. Scientists Wyatt Oswald and Andrew Richardson began this project in 2010, which has resulted in hundreds of thousands of photographs of the trees. The images allow Oswald and Richardson to document patterns and aberrations in the trees’ seasonal shifts–particularly budburst in spring, and senescence (or leaf coloration) and leaf fall in autumn. Their findings have demonstrated that the “green-up” of deciduous forests like the Common are very sensitive to climatic variability. In March 2012, they noted how record-breaking heat in Boston led the trees to leaf out in mid-March, rather than their typical time in early April. Commenting on the larger consequences of this finding, Oswald and Richardson wrote: “if the warmth of March 2012 gives us a sense of what the future holds for springtime in Boston, as climate projections suggest…then we can expect earlier leaf-outs and a substantial lengthening of the growing season. A failure to track these changes could be deleterious to the insect, bird, and mammal species that utilize urban forests as habitat.” Beyond the Boston Common, these phenological changes could shift competitive interactions between tree species, and have a deleterious impact on the carbon balance of forest ecosystems.

City parks and their verdant plant life are not only sources of respite and scenic beauty. Urban planners now consider green spaces to be important climate-resilient “green infrastructure.” Studies show that parks help mitigate the impacts of climate change by decreasing the urban heat island effect, absorbing stormwater runoff that leads to flooding, reducing fossil fuel emissions from vehicles, and sequestering and storing carbon through plant life. However, green spaces are seldom equally distributed across urban areas–with working class neighborhoods and communities of color often having less access to parks and plant life. This means that the scarcity of plants and green spaces proximate to communities of color contributes, in part, to the unequal harm they suffer from the climate crisis. In “A City of Equal Risks,” cartographer Emily Bowe visualizes how certain social groups in Boston are disproportionately impacted by climate hazards (based on the City’s 2019 Climate Ready Boston report). According to the report, the groups most at risk include: older adults, children, people of color, people with limited English proficiency, people with low or no income, people with disabilities, and people with medical illness. While the map shows that green spaces (including the Common) do mitigate the impact of urban heat in the surrounding area, parks and trees alone cannot rectify the many complex factors that play into climate risk in urban spaces.