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Climate Adaptation & Risk Management

The Arnold Arboretum of Harvard University, established in 1872, is the oldest public arboretum in North America. This botanical research institution and free public park is located in the Jamaica Plain and Roslindale neighborhoods of Boston, Massachusetts.                             

KPI 1a: Garden makes written and organizational commitment to address climate change in plans or policies.

With some 15,000 accessioned plants, representing almost 4,000 unique taxa that include 2,100 species, the Living Collections of the Arnold Arboretum (Arboretum) remain a major destination for those who study and enjoy woody plants. Of the accessions brought to the Arboretum from elsewhere, 50% are of wild origin, hailing from over 60 different temperate countries. This historic interplay between taxonomic, floristic, and cultivated diversities has resulted in one of the most comprehensive and heavily documented collections of temperate woody plants in the world. The living collections are central to the Arnold Arboretum—all research, education, and conservation initiatives are driven by them.

Because these collections are at risk of losing their prominence, and in advance of the Arboretum’s sesquicentennial in 2022, the Arnold Arboretum created a set of initiatives to simultaneously preserve its singular legacy and secure its future. This plan, to be enacted over the next decade, will thus serve to shape and define the Living Collections of the Arnold Arboretum for the coming century.

Photo to right: Plumleaf azalea (Rhododendron prunifolium), one of many threatened species conserved at the Arnold Arboretum. Photo by Ned Friedman.

The Arboretum’s Campaign for the Living Collections is a 10-year initiative to expand their Living Collections as a valuable resource for scientific research and conservation. The 400 taxa to be acquired in the next ten years, including 177 species of woody plants new to the grounds of the Arnold Arboretum, will have a profound impact on the character and value of the living collections. The efforts of this  decade-long campaign are aimed at renewing and reinventing the Arboretum’s legacy of discovery, natural history, and plant collecting to document, preserve, and study biodiversity in a world dominated by human-induced habitat loss and climate change.

The mounting effects of global change and habitat destruction threaten the survival of roughly one out of every five plant species on Earth. As ecosystems change across the world, cultivating a well-documented, institutional plant collection is not only instructive and useful to research and scholarship—it also serves a vital role in protecting biodiversity. The Campaign for the Living Collections aims to help science address global challenges over the next century by accelerating the Arboretum’s efforts to document, collect, and preserve plants, particularly those of critical conservation value. Over the next decade, these renewed efforts will develop the Living Collections as an incomparable resource for scientific study as well as a garden of outstanding substance and beauty.

As the Arboretum prepares for the most significant expansion of the Living Collections in their lifetime, the ability to provide quality care for plants in the landscape is of crucial importance. That’s why the Arboretum has committed additional resources to monitoring and improving growing conditions, as well as identifying adaptive and sustainable solutions to the challenges of preserving a diverse living collection. Their comprehensive Landscape Management Plan guides the proper oversight of each specimen’s individual needs, ensuring that plants collected from natural habitats around the world will be preserved at the Arboretum for the enjoyment and education of posterity. The content of the Plan has now been augmented with other collections, geographic, and operations data into an integrated and digital Landscape Management System.

Arborist AJ Tartaronis using the Arb Manager mobile app in a tree. Photo by Ben Kirby.

KPI 1c: Garden tracks and benchmarks progress of climate adaptation and mitigation strategies.

Governance of the living collections is established by the institution’s Collections Policy, a document that plays a role in decisions including acquisition and disposal, documentation, and maintenance of the plants. Curatorial procedures—including those related to records, nomenclature, mapping, inventory field checks, and plant labels—are the product of continuous refinement and have become models for other institutions. Nearly 150-years' of accession data are documented in the living collections database (BG-BASE), which integrates wild-collection details from the field, growth and phenology data from the grounds, as well as records of herbarium vouchers, verifications, and distribution scholarship and others’ collection building. From a mapping perspective, these collections data are integrated into the Arboretum’ s Geographic Information System as well, for internal and external visualization and analysis. The Arboretum system for propagation and distribution ensures that new material is successfully grown and that their collections are shared with like-minded botanical and horticultural institutions. Furthermore, the living collections are actively integrated into an average of 80-100 research projects annually, spanning a wide spectrum of the sciences and humanities.

Cat Chamberlain, a PhD candidate at Harvard University and a fellow of the Arnold Arboretum, observes seedlings overwintering in the common garden research plots at the Weld Hill Research and Education Building. Photo by Jon Hetman.

Collecting detailed weather data has been an ongoing interest at the Arboretum for nearly a century. Over the years, various departments and members of staff have observed and documented weather on the grounds, particularly in terms of plant hardiness, microclimates, seasonal plant phenology, and extreme weather events. Collection procedures have ranged from daily handwritten observations to highly automated systems that broadcast live weather data online. 

Staff began recording weather data in 1965 from a weather station installed at the Dana Greenhouses, a practice which continues today. In 2011, a new weather station was added at the Arboretum at the Weld Hill Research Building. With the ability to report and share information online, precise weather data can now be obtained by anyone with access to a computer or mobile device. This diagnostic tool is a useful resource for staff and the visiting public, providing a highly localized and robust picture of weather patterns.

These data can inform horticultural management strategies, enhance record keeping, and facilitate comparisons with field observations. The station utilized by the Arboretum features a highly modular design allowing for seamless integration of a wide variety of climatic sensors. Currently these sensors monitor temperature, relative humidity, barometric pressure, rain, leaf wetness, solar radiation, soil temperature, and wind speed and direction. 

In addition to their central weather station, for several years starting in 2008 the Arnold Arboretum gathered data from 18 micro-stations dispersed throughout the landscape in order to identify microclimates on the grounds. This information is highly valuable for both mapping climate patterns over time and for locating areas of the landscape where plants of marginal hardiness may be sited to improve their chances of survival. 

2a: Garden consults or collaborates with others to learn, apply, and align climate change adaptation strategies to reduce carbon footprint and improve operations. 

  • The Arboretum has undergone some energy audits and improvements to facilities (windows, LED lighting), as well as the fleet (some electric vehicles as well as bikes) to reduce their carbon footprint.
  • The Arboretum is an active member of the Green Ribbon Commission, a group of business, institutional, and civic leaders in Boston working to develop shared strategies for fighting climate change in coordination with the City’s Climate Action Plan.
  • The Arboretum works with Harvard University Office of Sustainability to align their operations and management strategies with Harvard's Climate Action Plan, including review of capital projects.
  • The Arboretum collaborates with other gardens to share advances in landscape management practices and technology.  

2B: Garden devotes resources (staff and budget) to ensure core assets are safeguarded from climate change. 

Photo on top: Horticulturist Brendan Keegan utilizing a new cargo bike and trailer set up for landscape maintenance. Photo by Andrew Gapinski.

Photo on bottom: Seasonal Arborist Anthony Lombardo, Gardener Brendan Keegan, and Horticulturist Laura Mele help plant 2,500 plugs of butterfly milkweed (Asclepias tuberosa) in a reduced-mowing meadow on Peters Hill, enhancing the value to pollinators. Photo by Jon Hetman.

  • The Arbretum has constructed new path systems and refurbished existing ones to divert foot traffic from root systems and reduce soil compaction.
  • The Arboretum has invested significantly in facility improvements to increase envelope performance and environmental controls. These include new energy efficient windows and irrigation/misting systems at the Dana Greenhouse, planned envelope restorations at the Hunnewell Building, new smart HVAC controls at the Hunnewell Building, and planned environmental control and security improvements for the Library and Archives. 
  • The Arboretum recently launched Arb Manager and the Landscape Management System Dashboard, two technologies geared at streamlining horticultural operations and management. 

KPI 2c: Garden plant collections are prioritized, managed, and safeguarded in anticipation of climate change.

The Living Plant Collections Policy identifies Core Collections (which include 8 Nationally Accredited Collections), as well as unique, signature specimens.

Upon return from expedition, the Arboretum shares seed to USDA-NPGS germplasm repositories (AMES and WLPGR). There have been a few cases, namely Fraxinus, where high-value lineages were shared with NRP in Colorado for cryopreservation, should Emerald Ash Borer wipe them out of their collection.

The Dana Greenhouses serve as the point of entry for all accessions acquired for the living collections. Over the past two decades, propagation staff have germinated seed from expeditions to the Caucus region of the former Soviet Union, the People’s Republic of China, Taiwan, Japan, South Korea, Europe, North Africa, and North America. An average (3 year [2017-2019]) of 216 seed accessions are processed annually.

While seeds are a primary means of collections development, plants, and propagules (e.g., softwood and hardwood cuttings, grafts) are also collected and received. Some of these materials support repropagation efforts employed to conserve accessioned plants whose health is threatened by age, storm injury, and/or damage by insects or disease. Others are acquired to fulfill discrete collections enhancement goals. 

Plants grown from seed or propagule remain within the greenhouse compound for an average of five to seven years. During this time, observations on hardiness and vigor are catalogued in their database of record (BG-BASE). Only after rigorous evaluation do plants of an appropriate size make their way to the grounds by way of container, bare root, or drum-laced balls.

KPI 2d: Garden educates the public on climate change impacts through programming, interpretative elements, and landscape designs.

The Arnold Arboretum offers a multi-day institute every summer intended for educators. Each institute has a different focus and varying target audience. Preference is given to teachers from the Boston Public Schools (BPS) and encouraged teams of teachers (up to 4 people) from the same school to apply together. In 2019, eighteen teachers, a majority from public schools in Boston and surrounding communities, learned teaching strategies for field ecology and elements of climate change.

The principles and strategies of field ecology were explored at the Arboretum’s Kent Field and Central Woods, where middle and high school teacher participants established study plots to use during the week. Teachers took plant samples to press and identify, engaged in biodiversity inventories, collected abiotic data from temperature and soil pH to moisture and soil hardness, and filled a field journal with their sketches, observations, and questions. Daily visits to their plots increased the teachers’ confidence with the outdoors and helped them notice new phenomena each time.

Photo: Horticulturist Brendan Keegan explains monarch and milkweed survival strategies to educators in Kent Field.

In addition to nurturing accessioned material for the permanent collection, greenhouse staff grow plants for the spring dividend and special events. Services are also rendered for researchers, nurseries, institutions, and individuals. Learn more about the availability of research and propagation materials or join the Friends of the Arboretum for opportunities to grow notable plants in your own landscape.

The Arboretum also leverages global and national events to educate the public, for example, May 18 is celebrated around the world as Plant Conservation Day. Because botanists estimate that one in five plants are threatened with extinction globally, botanical gardens and arboreta play a critical role in preserving and sharing the germplasm of plants collected in the wild. Plant conservation is important at the Arboretum, where we collect, cultivate, and document as many threatened and endangered plants as possible.

How does the Arboretum know which plants are threatened globally? An important part of their work includes an annual assessment of our accessioned plants using BGCI’s PlantSearch and Threat Search tools to determine which are of conservation concern. Armed with the knowledge of each plant’s conservation status, the Arboretum can then prioritize them for extra care and maintenance, repropagation in advance of premature decline, passive and active education programming, and distribution for collection building and scholarship. In fact, as a means to get these rare plants studied, the Arboretum prioritizes their use when scholars request material but have no preference.

Learn about more ways the Arboretum's educational programming addresses climate change.

The Arboretum is undertaking several major sustainability initiatives to combat the effects of climate change at a local level, including a large-scale drought mitigation project and solar energy generation. Learn more about the Arboretum's climate and sustainability initiatives here.

Contact Information

Address: 125 Arborway, Boston, MA 02130

Area: 281 acres

Designated NHL: January 12, 1965

Architect: Frederick Law Olmsted