The Center for Tree Science: Securing the future of trees

Around the world, trees are under threat in the wild and in urban areas. Only concerted effort can preserve tree diversity, urban forests, and the many benefits they provide to people and the environment. But those efforts are hampered by a lack of scientific understanding of the complex challenges faced by trees and forests and by a diminishing pool of people trained to meet those challenges. The Center for Tree Science at The Morton Arboretum catalyzes scholarship and training for the future of trees and people.

What is the Center for Tree Science?

The Center for Tree Science brings together experts from botanical gardens, universities, government, industry, and other organizations to participate in collaborations that generate new knowledge and provide training to address key challenges facing trees in urban areas and in the wild. The Center for Tree Science follows a simple consortium model and engages a Steering Committee to guide scientific objectives.

The Center works towards its goals by supporting the following activities in which collaborators can be involved: collaborative research projects; small grants; fellowships; internships; mini-courses; workshops; conferences; a program for undergraduates to gain research experience; and a research and demonstration area on the grounds of The Morton Arboretum to engage the public. By creating a nucleus of experts who regularly work together, exchange ideas, and use their collective achievements and strengths to increase research, training, and funding opportunities for tree science, the Center for Tree Science energizes tree science and serves as a primary source for expertise on trees. 

Find out more about the Center for Tree Science.

Read the sections below or download the complete  PDF iconCenter for Tree Science Strategy (PDF)

Literature cited

Improving the quality of urban forests

Trees and forests in urban areas and in the wild provide essential benefits to society and the environment but face increasing challenges that put them at risk.


Benefits urban forests provide to communities

The urban forest improves the lives of more than 220 million people in the United States alone, or 80 percent of the population, and with urban populations projected to grow, the number of people who benefit from trees in urban areas will increase (U.S. Census Bureau 2010; Nowak et al. 2010).


Trees play important roles in the urban ecosystem because they:

  • Clean pollutants from the air
  • Reduce energy use and noise pollution
  • Improve water quality and help control flooding
  • Increase property values; provide wildlife habitat
  • Mitigate changes in climate
  • Improve community health and well-being 

(e.g., Dwyer et al. 1992; McPherson et al. 1994; Westphal 2003; Nowak and Dwyer 2007).


These benefits are valued by communities and society

Although not usually included in municipal budgets, the services trees provide are worth millions each year (e.g., Nowak et al. 2008; Nowak et al. 2012). Increasingly, these services are being quantified and incorporated into infrastructure planning and municipal budgets (Nowak 2006). Demand for tree care services has increased over the past two decades (O’Bryan et al. 2007), and is projected to grow 26 percent over the next decade (Wiseman et al. 2011).


Threats to urban forests

Despite their importance, urban forests face considerable threats.

  • Budget constraints often limit municipalities’ ability to hire skilled staff and dedicate adequate resources to properly care for trees.
  • Urban forests often have low species diversity, are not planted with species tolerant to climate changes, and are vulnerable to pests and disease (Santamour 2004; Tubby and Webber 2010).
  • In some cities, many of the large trees responsible for the bulk of important ecosystem services are legacies from the presettlement landscape and these legacy trees are now reaching the end of their natural lifespans (Fahey et al. 2012).

We will lose much of the valuable services trees provide if we do not move to improve our ability to manage and care for the urban forest.


Research is required to confront threats and improve urban forests

Our aim should be a diverse, resilient, and climate change-ready urban forest. To achieve this we must understand how to grow trees successfully in these areas; determine how they function within the surrounding ecosystem; develop new tree varieties with traits for urban conditions; accurately quantify the value of trees; devise improved planting and care techniques for urbanized regions; and optimize urban forests for an uncertain future climate. The Center for Tree Science coordinates the type of collaborative, innovative research and dissemination of results required to tackle these issues and ultimately help secure the future of trees in urban areas.

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Protecting global tree diversity

Worldwide, trees in the wild have tremendous ecological, economic, and cultural importance. They are the backbones of terrestrial biodiversity and provide vital ecosystem services like soil stabilization, groundwater purification, and nutrient cycling. Trees represent a rich evolutionary history and genetic reservoir, as roughly one in four flowering plant species is a tree. Globally, forests store more than 650 billion tons of carbon, more carbon than is present in the entire atmosphere (FAO 2010). Trees are also valuable sources of fuel, fiber, medicine, timber, and food for people.


Threats to tree species in the wild

Globally, 8,000 species, or 10 percent of all tree species, are threatened or endangered due to many factors such as:

  • Habitat loss
  • Overexploitation
  • Pressure from invasive species
  • Climate change

(Oldfield et al. 1998; Newton and Oldfield 2008, Oldfield and Newton 2012)


Protecting global tree diversity requires an approach that incorporates a wide variety of complementary techniques that include both ex situ and in situ conservation (Maunder et al. 2004). These conservation strategies must be informed by tree science-based research including:

  • Species distribution mapping
  • Reproductive biology
  • Phylogenetics
  • Germplasm storage
  • Micropropagation and tissue culture
  • Population genetics
  • Conservation collection assessment
  • Reintroductions
  • Restoration ecology

(Falk 1987; Havens et al. 2006; Oldfield and Newton 2012).


Public gardens can leverage their expertise and engage in larger research collaborations

Public gardens and arboreta have an increasingly important role to play in global tree conservation, yet their resources are often underutilized toward these ends (Maunder et al. 2004; Crane et al. 2009; Cibrian- Jaramillo et al. 2013). The Center for Tree Science facilitates tree conservation by supporting targeted research efforts and catalyzing global collaborations that combine diverse perspectives, expertise, and resources to safeguard tree species from extinction.

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Gap in support for tree science

Considering the benefits trees provide, the threats they face, and the creative and challenging research needed to confront and overcome these threats, tree science requires increased support. Yet, in fact, support is declining. Resources for tree science research and training have been decreasing for two decades (Kramer et al. 2010; Hayes 2013—data for botany and horticulture in general), significantly diminishing the quantity of research and the number of students pursuing careers in tree science.


Decline in government funding and expert personnel

Government funding has fallen for federal agencies, land grant universities, and state departments of natural resources that once hosted robust research teams.

  • Federal funding for research and development has declined 9. 2 percent over the past five years, trend likely to continue (Yamaner 2013)
  • Greatest decline has been in environmental research, down 21.4 percent (Yamaner 2013)

The vast majority of the remaining tree-related state funding is directed towards municipal tree planting, management, and inventory and is not available for research.

Institutions such as the USDA are losing experts as those who retire are not replaced (BRP Final Report 2004).

  • USDA Forest Service has lost 46 percent of its scientists since 1985 (Committee on National Capacity in Forestry Research 2002)


Land grant university restructuring has decreased concentration of specialized experts

Large land grant universities have historically hosted stand-alone departments in horticulture and forestry, employing multiple tree experts.

  • Over the last 20 years, programs have lost faculty and been collapsed into larger, more general departments, which means a reduction in research focused on tree science.
  • Losses have produced a decline in new knowledge generated to support arboriculture, urban forestry, and tree conservation. For example, citations have fallen significantly over the past 20 years in ISI-indexed journals for core tree science topics such as “arboriculture” and “pathology.”

Tree science faculty now must look outside their institutions to form the meaningful collaborations necessary to tackle difficult research questions and train students in techniques vital to tree science (Hayes 2013; Hockenberry Meyer et al. 2010).


Opportunities for students to study tree science is in decline

  • University programs now attract fewer students in arboriculture, horticulture, and other tree-specialist areas than they did 20 years ago (Kramer et al. 2010—data for botany and horticulture in general).
  • University classes on plant identification and field work have been replaced by courses focusing on topics such as genetic methods that, while important, have resulted in a decline of students graduating with the knowledge necessary to document tree and plant diversity and understand evolutionary processes (Hayes 2013).


Decline in skilled tree professionals, while demand is up

These changes have resulted in a lack of skilled tree and plant professionals.

  • Availability of forest entomologists and forest pathologists is at an all-time low (Keathley 2003), even though threats to forests from pests and disease are at an all-time high, due to species introductions and global climate change.
  • Tree care industry is demanding not only more employees, but more employees with four-year degrees and supervised field experience (Elmendorf et al. 2005; Wiseman et al. 2011).

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Opportunity to strengthen and energize tree science

With these grand challenges facing urban and wild trees, there is an urgent need for a leading botanical institution to invigorate tree-focused research and training. The Morton Arboretum is ideally positioned to fulfill this need by developing and supporting the Center for Tree Science. The Morton Arboretum’s mission to encourage the planting and conservation of trees provides a strong foundation for the Center and ensures sustainable and enthusiastic institutional support.


The Morton Arboretum’s long history of research makes it an ideal host for the Center for Tree Science

The Center for Tree Science has the advantage of The Morton Arboretum’s 90-year history in tree science, which provides a base of expertise and an extensive network of connections within academia, the green industry (arborists, nurseries, landscape management), the botanical garden and arboretum community, government, and environmental nongovernmental organizations. The Arboretum is known for its research on:

  • Tree planting and establishment
  • Urban soils
  • Tree selection and improvement
  • Tree biomechanics
  • Forest dynamics
  • Ecosystem management and restoration
  • Biodiversity
  • Endangered species recovery
  • Historical vegetation patterns
  • Phylogenetics

Its living collection and herbarium hold important specimens and significant genetic resources for research and conservation.


Facilities available to the Center at The Morton Arboretum

While not all Center for Tree Science research and training is expected to occur at The Morton Arboretum, to support Center activities, the Arboretum offers:

  • Well-equipped laboratories
  • An herbarium
  • A world-renowned tree collection
  • Field research plots
  • Large areas of restored and natural plant communities.
  • Meeting spaces
  • Staff to provide logistical support for classes, conferences, and workshops.
  • Opportunities to bring tree science research results to broad audiences
  • Nearly 900,000 annual visitors.
  • A research and demonstration area where research can be conducted, interpreted, and showcased to the public is being developed on arboretum grounds.


Arboretum programs available to support Center activates

As one of the leaders in establishing professional standards for tree-focused gardens, The Morton Arboretum coordinates ArbNet, an interactive community of arboreta that supports professional exchange and development. This network offers unique opportunities for collaboration, especially with smaller or nontraditional arboreta. The Morton Arboretum’s Community Trees Program, which provides outreach on tree care and pest management to municipalities and homeowners, is leading a collaborative strategy to improve the vitality of Chicago’s forest by 2040. Improvements in current practices developed through Center research can be disseminated through these channels.


Secure funding base

The Morton Arboretum has a secure funding base and a history of innovative and effective resource development and program management, which will enable the Center for Tree Science to expand funding opportunities for tree-focused research.


Location provides research opportunities

Finally, the Arboretum is located in the midst of an urban forest in the Chicago metropolitan area that is home to 10 million people. The region has 157 million trees across an urban-to-rural gradient, as well as 225,000 acres of protected natural areas, together providing a multitude of research opportunities. The Center is able to coordinate long-term studies in this model urban forest ecosystem.

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Center for Tree Science strategy

The vision. The Center for Tree Science takes a focused approach to impact key areas of tree science. Research projects and training opportunities are directed towards the grand challenges facing trees and forests in urban areas and tree species in the wild. Work at the Center strives to make unique contributions within these two broad themes. It involves basic and applied research, connects experts and practitioners, and disseminates information to targeted audiences to influence best practices in science and conservation. The Center for Tree Science amplifies the efforts and achievements of all collaborators, making their endeavors more attractive to funders, as investments will produce greater impact than investing in one institution, laboratory, or researcher alone.


The structure. The Center for Tree Science has a simple consortium-based management model, so that all partners have ownership of innovative, successful research and training projects. The goal is to attract collaborators at the top of their fields; early-career scientists; students; practitioners eager to learn; and industry and institutional partners enthusiastic about advancing tree science and improving practices.


A steering committee composed of leaders in tree science guides the scientific objectives of the Center, sets specific targets for research and training endeavors, and assists in encouraging collaborators and tree experts to become involved with the Center for Tree Science.


There are several roles for involvement in the Center for Tree Science: as a member of the Steering Committee, an Affiliate, a Collaborator, or through the Fellowship Program. Center for Tree Science Affiliates have developed long-term affiliations with the Center. They can be collaborators involved with a number of collaborative research projects (CRPs); potential reviewers for CRPs under consideration for sponsorship; or professionals interested in Center research and training efforts. Collaborators are scientists involved with CRPs and may have short- or long-term involvement with the Center. The Fellowship Program offers sponsored opportunities to formally engage a range of researchers, from students and early career scientists to senior researchers, in specific CRPs. Other opportunities for involvement may simply be through participating in an internship, mini-course, conference, or workshop.


The work. The Center for Tree Science increases tree science research and training opportunities by supporting:


Collaborative Research Projects (CRPs). To generate new knowledge, the Center for Tree Science hosts and in some cases partially funds cutting-edge, cross-disciplinary projects that address aspects of the grand challenges to trees in urban areas and in the wild. Projects allow experts such as faculty at academic institutions, researchers from industry, and scientists from botanical gardens and government agencies to join forces and pool knowledge. The Arboretum provides administrative support for CRPs when needed and hosts working group meetings and conferences. The Center helps collaborators disseminate research results and best practices to appropriate audiences.


Research Fellowship Program. Early-career and senior scientists may receive support from the Center for Tree Science through the Fellowship Program. Research Fellows receive support to participate in CRPs or serve in advisory roles.


Undergraduate Research Fellowship Program. Undergraduate Research Fellows participate in a formal 10-week course at The Morton Arboretum that brings students through the steps of a scientific research project, including project development, data collection, analysis, and presentation. Each student has a designated mentor from a collaborating institution who is currently involved in a CRP. The program is designed to foster intellectual development, critical thinking, independence, self-confidence, and perseverance in students, as well as to contribute to ongoing Center for Tree Science research. A well-developed tracking, evaluation, and reporting program gathers feedback from students for continual program improvement.


Internships. Students can get hands-on experience in tree science and arboretum collections through internships, either as Student Fellows receiving Center support or as interns with support from other sources. Internships are coordinated with Center activities, so that participants work on an aspect of a Collaborative Research Project or explore issues related to the grand challenges. Internships help fill the training gap in tree science, conservation, and collections, and provide the tree care industry with graduates who have hands-on, supervised experience.


Small grants. Modest grants allow students and early-career researchers to perform research or undergo training at collaborating institutions. Early-career grants encourage promising scientists to participate in Collaborative Research Projects. Small grants may provide leverage to attract additional funding, which can be especially important for early-career scientists and students. These grants have a large impact for a small investment.


Mini-courses. To further fill the training gap, the Center collaborates with partner institutions to develop mini-courses that communicate new knowledge and best practices. Mini-courses focus on topics being lost from traditional arboriculture and horticulture programs, as well as those related to the grand challenges and special to botanical garden and arboretum collections, such as managing collections for the conservation of tree species. Courses are held at the Arboretum or partner institutions and instructors are recruited from institutions interested in collaborating. These courses have high impact for relatively low investment. Students and young professionals in arboriculture, horticulture, arboretum management, and related fields are exposed to leading experts and cutting-edge knowledge in tree science, gaining experience and understanding that they will apply throughout their careers.


Workshops and conferences. The Center for Tree Science supports meetings that bring together experts to discuss research, disseminate new techniques to practitioners, and provide information to the public.


Research and demonstration area. An outdoor space at The Morton Arboretum is being designed specifically to support research initiatives and showcase Center for Tree Science research to a range of audiences. Research performed and exhibited in this area will catalyze discussion among industry experts and tree scientists, as well as demonstrate research objectives and results to the public.


Audiences, scope, and assessment. The Center for Tree Science works to understand its audiences and their needs, which is key to effectively communicating science outward. Research and collaborations at the Center for Tree Science may be regional, national, or international in scope. Research, training, and other activities are formally tracked and monitored using state-of-the-art practices, so that all Center activities involve a complete cycle of science, education, training, implementation, impact, assessment, and improvement.

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Ultimately, the Center for Tree Science seeks healthier trees and forests in urban areas, tree species protected from the threat of extinction, and a well-trained next generation of tree scientists and professionals. For the Center for Tree Science to have maximum impact, it must influence changes in practice. This may mean implementing new techniques for the planting and care of trees or developing new models that change how collections are managed so they contribute more directly to tree conservation. As a result of Center for Tree Science work, more students will be exposed to tree science research and more professionals will be informed of and able to implement best practices in tree care and management. More botanical gardens and institutions will be engaged in promoting tree conservation and improving collections management to contribute to the conservation of threatened tree species.


Planning and implementation

The Center for Tree Science will build on early successes to garner support and collaborators. The Center currently has several CRPs underway (see “Current Projects” below), which are demonstrating best practices for future CRPs. Staff members of The Morton Arboretum are leading these initial projects and initiatives as the Center for Tree Science develops.


Development of the Center is being led by the Arboretum’s Vice President of Science and Conservation, Dr. Nicole Cavender, and its Head of Research, Dr. Gary Watson. The Center’s first Undergraduate Research Fellowship program was initiated in summer 2014 and included 8 students from across the US. The students, with guidance from mentors, identified questions, conducted research, and presented their work. In addition, planning is underway to attract partners from arboreta, botanical gardens, universities, industry, and government organizations, as well as to build more specific and formalized collaborations to accomplish innovative tree science research and training. The first Center for Tree Science Steering Committee is being formalized. The Center for Tree Science is also developing a plan for a multiyear, multicollaborator research initiative centered on oaks and their ecosystems in urban areas and threatened species in the wild, as another large-scale first-phase Collaborative Research Project.


A plan to improve space and equipment at The Morton Arboretum to support Center for Tree Science activities is being developed. A master plan for the research and demonstration area is underway, including interpretation space and expanded space for tree research on Arboretum grounds. The Morton Arboretum is also planning to hire a director and other researchers to help grow the Center for Tree Science.


The Center for Tree Science represents a major opportunity to marshal forces in tree science research and provide training opportunities to meet the grand challenges that threaten trees and the benefits they bring to people.

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Literature Cited

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Yamaner, M. 2013. Federal funding for research drops by 9% in FY 2011. National Science Foundation 13–336. Available at: Accessed 6 February 2014. 

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