• Start-up
  • Planning
  • Action
  • Evaluation

Guidelines for selecting tree species that support the
biodiversity of Takoma Park’s ecosystem in the context of climate change
 

In 2020, the City Council of Takoma Park, MD adopted several goals to manage the city’s urban forest, including “increase biodiversity through a focus on native trees, and where appropriate, climate-adapted trees.” This project, initiated by Friends of Native Trees in Takoma (FONTT), will develop guidelines for selecting tree species in line with this goal, by using the data that NIACS has assembled on the climate adaptabilities and vulnerabilities of trees native to Takoma Park’s ecosystem. FONTT will communicate to residents, councilmembers, and city staff how they can use the guidelines to choose tree species appropriate to the local ecosystem.

Project Area

Municipal boundaries of Takoma Park
Takoma Park, Maryland is a municipality of 17,500 residents in a two square mile area. Its location borders Washington, D.C., putting Takoma Park roughly in the center of the sixth largest metropolitan area in the country. Due to a strong municipal tree ordinance enacted in the 1970s, an urban tree canopy of 57% covers the city. Traversing the city is a county-managed park, which is part of the ecological hub and corridor network at the heart of the state’s conservation strategy. The yards of single-family homes contain the largest portion of the urban forest and offer the largest unbuilt space for planting additional trees. Public land along streets (rights-of-way) make up the second largest space available for tree planting.

Management Goals

Pie chart of land use in Takoma Park

Goal: Plant trees that will support biodiversity in the ecosystem where Takoma Park is located.

 

 

 

 

 

Objectives:

  • Identify the Takoma Park ecosystem and the tree species native to it. 

  • Organize and present available information on the climate adaptabilities and vulnerabilities of these native tree species. 

  • Consolidate this information in practical guidelines for selecting tree species to support biodiversity in the Takoma Park in the context of climate change.

  • Communicate the main message from this information and the guidelines to Takoma Park residents, councilmembers, and city staff.

Climate Change Impacts

Tree species differ with respect to their adaptability versus vulnerability to specific climate change stressors. In Takoma Park, the key anticipated stressors are as follows:


  • Alternating periods of heavy rain and drought are predicted. Excessive precipitation can limit access to oxygen and compact the soil. Compacted soil limits access to oxygen and nutrients and inhibits water penetrating the surface. Subsequent drought further increases water stress. A mortality spiral develops and trees ultimately succumb to stressors, such as pathogens or insects.
  • Increased maximum temperatures during the summer and fall can stress transplanted trees, as well as certain species.
  • A longer growing season may increase the susceptibility of transplanted trees to insects and pathogens before, during, and after planting. On the other hand, the growth of the trees in the first years after planting may benefit from the longer growing season.
  • New invasive species and pathogens may migrate into the area due to warmer temperatures.
  • More violent storms can damage and uproot trees. Damage not initially fatal can leave trees vulnerable to insects and pathogens.
     

Challenges and Opportunities

Climate change will present challenges and opportunities for accomplishing the management objectives of this project, including:

Challenges

Oak trees, the predominant tree species in the local forest, suffer from oak decline due to a combination of factors.
Knowledge of the composition and health of the Takoma Park urban forest is limited and anecdotal. The city does not maintain an inventory of city-owned trees and does not track the lifecycle of these trees.
Awareness of the city biodiversity goal has dropped precipitously since its adoption, in part because its purpose and practical implications are not clearly stated and broadly agreed upon.
Many native tree species are not readily available to the city or homeowners. The selection of tree species available from a single supplier limits the range of species and genetic diversity planted by the city.

Opportunities

NIACS has data that identify the climate adaptabilities and vulnerabilities of tree species in urban areas.
Maryland has over 120 native tree species, with ranges that extend well to the north or south of the state.
City has contracted LiDAR assessments of tree canopy coverage in 2010, 2019, and-2022.
Recently, the city started to maintain a database of city-financed trees that it plants annually and to make this information available through GIS maps on the city website.
The city has a relatively strong municipal tree ordinance.
Maryland has launched the Maryland Native Plants Program to increase the production and sale of plants native to Maryland.

Adaptation Actions

Project participants used the Adaptation Workbook to develop several adaptation actions for this project, including:

Area/Topic
Approach
Tactics
Maintain and enhance species and structural diversity.
Review the scientific literature on the relationship between native plants and biodiversity in the ecosystem.
Identify tree species native to Takoma Park, according to the Biota of North America Program, the Maryland Plant Atlas, and historical records.
Identify tree species native to the Takoma Park ecosystem, using “ecosystem” as defined by the Northeast Terrestrial Wildlife Habitat Classification System (NETWHCS) and the Ecoregions Framework developed by the Environmental Protection Agency.
Identify some of the common non-native species presently being planted in Takoma Park.
Facilitate composition adjustments through species transitions.
Consolidate available information on the climate adaptabilities and vulnerabilities of the above native tree species, primarily based on data provided by NIACS, in a spreadsheet.
Develop guidelines: a profile for each native species with information on biodiversity value, desirable site conditions, and climate adaptabilities and vulnerabilities.
Community outreach.
Prepare written materials, short videos, and other media distilling the main messages from the guidelines.
Organize events and activities to communicate these messages to the target audience: Takoma Park residents, councilmembers, city staff and other community members.

Monitoring

Project participants identified a set of key monitoring questions and corresponding monitorable variables. The project should be completed by January 2025.

1. Did we identify the ecosystem where Takoma Park is located and a list of tree species native to that ecosystem?
*A document presenting this information is available on the FONTT website.

2. Did we explain the climate adaptabilities and vulnerabilities of the identified native species?
*A spreadsheet giving available data from NIACS and a variety of other sources on climate adaptabilities and vulnerabilities by native tree species has been produced and can be shared upon request.
*A document summarizing the spreadsheet and explaining its significance and use has been reviewed by forestry experts and is available on the FONTT website.

3. Did we provide guidelines for selecting native tree species in the context of climate change in Takoma Park?
*Individual profiles have been developed for at least half the native tree species, with information on each species’ biodiversity value, desirable site conditions, and climate adaptabilities and vulnerabilities.

4. Did we disseminate the main messages from the research and guidelines?
*A webpage summarizing the main messages and providing links to the documents and guidelines is available on the FONTT website. The webpage has received at least 500 unique visitors.
*Short videos and other communication materials have been produced to aid in delivering the main messages at events and in driving traffic to the website.
*Zoom and in-person events have been held to explain and discuss the main messages.
*A survey of FONTT members indicates the successes and gaps in delivering specific messages.

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