Glossary

This glossary is intended to be a resource for navigating our website and gaining a better understanding of the work we do and the language we use. We recognize that language can hold deep meaning across different communities and some may define these terms differently based on their own lived experiences. Please explore this resource and we encourage you to think about your own way of defining these terms.

  • Species that may thrive in new environments as climate change alters temperature, precipitation, wildlife, and soil conditions, modifying the range where a native species can grow. Planting adaptive species now is one way to work towards a more resilient forest in the future. 

  • The combined science and art of individual tree care, cultivation, and management. Arborists carry out this discipline through targeted planting, pruning, management, preservation, and removal of trees. In our region, the PNW ISA is the certifying organization for arborists.

  • A toolbox of different strategies we use to prepare for the current and future impacts of a changing climate, including planting adaptive species. The goal of these strategies is to strengthen our relationships, infrastructure, and natural environments to thrive under changing conditions. Trees are part of climate adaptation because they cool off urban environments.   

  • Strategies targeting the sources of climate change to prevent further escalation, including reducing greenhouse gas emissions and increasing natural carbon sequestration sources such as our forests. Trees are part of climate mitigation because they consume carbon dioxide and prevent it from further heating the atmosphere.

  • The process of breaking up and removing paved surfaces in order to increase plantable space and aid in rainwater reabsorption. Pavement is an impermeable surface that presents barriers to tree planting and exacerbates stormwater runoff and the urban heat island effect. 

  • Communities have the right to safe and healthy places to work, live, and play free of environmental hazards, along with the autonomy and agency to be active participants in the decision making processes that impact their community. The environmental justice movement was born out of overburdened communities, and we continue to champion this tradition. In many communities, a lack of tree canopy is correlated with lower life expectancy, reduced air quality, and increased temperatures. Because trees are an indicator of investment patterns that systematically advantage some neighborhoods and disadvantage others, working toward tree equity is an important aspect of environmental justice.  

  • The intentional and systematic placement of environmental hazards in communities of color. Further compounded by the severing of relationships between communities of color and the environment, through environmental degradation and exclusionary policies like redlining.  

  • Surfaces that do not allow water to pass through them. Some examples include roads, parking lots, roofs, and compacted gravel.

  • Species introduced into an ecosystem that do not occur naturally and can impact biodiversity or human health. Not all non-native species are considered invasive; some can become adaptive to new environments, particularly in changing climates, and cause little harm.

    See also: Native Species, Adaptive Species.  

  • Species that are indigenous to a particular area or ecosystem, having adapted to the area over thousands of years without human intervention. 

  • The Right-of-Way (ROW) includes the impervious surfaces–street, sidewalk, compacted gravel–and grassy areas that sit between the road and private property and functions as a conduit for the public’s comfort, benefit, and travel throughout the city. Trees planted within the ROW are considered street trees and maximizing this planting space is crucial for achieving tree equity and maximizing tree benefits for our communities.

  • A woody perennial plant characterized by its size, usually 10 feet in height or smaller, and multiple stems growing from the ground. Shrubs play a crucial role in supporting biodiversity and reducing stormwater runoff in urban settings, while maximizing smaller plantable spaces.

  • Stormwater includes rain and other water sources that flow through our urban environment, picking up pollutants and carrying them to our local waterways. Trees play a role in mitigating stormwater runoff through intercepting rainfall, water reabsorption, and filtration. 

  • Thoughtful planning and action to ensure the longevity and abundance of our land and resources for generations to come.

  • A woody, perennial plant, characterized by one leading stem, a grounded trunk, significant height, and a long lifespan. Trees bear great significance across cultures and communities, regarded as a symbol of life, health, knowledge, and transformation. At TTF, trees are deeply personal to the work we do and the impact we intend to have, as they are not a singular solution to any problem, but an active part of the answer to so many.

  • From a birds’-eye view, the network of branches and leaves that cover the ground. An individual tree’s mature canopy will vary in size depending on the species, contributing to our citywide mosaic. Tree canopy is directly related to the temperature, biodiversity, and stormwater efficiency we experience in our neighborhoods, along with a myriad of social and health benefits.

  • The guiding vision that everyone has access to and experiences the benefits of healthy and abundant tree canopies. We are working towards tree equity in response to a history of unfair and unequal development that has concentrated the wealth of tree benefits in predominantly whiter and wealthier communities. 

  • Dedicated web of government, non-profit, private, community organizations, and community members with skills, capacity, and expertise who preserve, manage, and advocate for the trees within our cities. Directed by the goals, objectives, and regulations outlined in urban forestry municipal codes and management plans.

  • The process of providing the necessary amount of water for young trees, utilizing tools such as watering bags or buckets to ensure maximum absorption of water and limit runoff. Newly planted trees have shallow root systems and require consistent, manual watering to assist them in establishment and prevent heat stress during the warmer months.