Afforestation — the planting and cultivation of forest in an area that was not previously forested.

Basal area — the area of the cross section of a tree at breast height (4.5 ft. off the ground). Basal area can be estimated by the tree’s diameter at breast height (DBH), and is used to determine stand density, as well to guide management decisions such as thinning and harvest.

Carbon markets (compliance and voluntary) — carbon markets are economic markets for trading carbon emissions credits, towards the goal of reducing greenhouse gas emissions. Compliance carbon markets are created and regulated by mandatory international, federal, or more localized carbon agreements (eg. the Paris Climate Accords, or California’s Cap & Trade program). In compliance systems, a limited number of emissions allowances are issued for polluting entities to purchase. These entities can also purchase credits to offset emissions, generated by projects such as forest carbon projects. Market supply and demand determines the price of carbon credits. Voluntary markets allow non-regulated entities to purchase carbon offsets voluntarily and outside of a regulatory framework, rather than to meet compliance emission reduction requirements.

Carbon offset — a reduction in carbon dioxide emissions used to compensate for carbon dioxide emissions elsewhere. In a carbon market, offsets credits are commodities that can be purchased to compensate for carbon emissions. The payment to purchase the offset can be used to fund action to reduce atmospheric carbon. A carbon offset is defined as the sequestration or reduction of one metric ton of carbon dioxide equivalent (CO2e).

Carbon sequestration — the process of capturing and storing atmospheric carbon dioxide. Plants naturally absorb and store carbon in biomass through photosynthesis. In the context of forests, carbon can be stored in both living and dead biomass, as well as aboveground and belowground, and in harvested timber.

Climate-smart forestry — forest management practices that maintain and restore forest ecosystems, remove and sequester more carbon than conventional practices, and increase forest resiliency in the face of climate change. A range of climate-smart practices and climate-smart wood products exist. Wood products sourced from Forest Stewardship Council (FSC)-certified forests, as well as wood sourced from restoration projects or other ecologically managed forests are examples. Dialogue about climate-smart wood acknowledges that the carbon sequestration and climate impacts of wood vary depending upon origin and management practices. There is a growing interest in decreasing the carbon footprint of buildings, and building with climate-smart wood is one potential strategy to do so. To be a sustainable strategy, climate-smart wood must consider values and management impacts beyond carbon sequestration, e.g. protection of old growth and other high conservation value forests, and protection of biodiversity, water resources, and human rights.

Community forestry — a localized approach to forest management wherein a working forest is owned, governed, and managed by local community stakeholders such as municipalities, government agencies, tribes, and NGOs. Community forests are managed according to the community’s distinct needs and goals for social, ecological, and economic outcomes and may include a combination of timber harvest, recreation, restoration, education, protection of traditional food sources and other cultural resources, and/or provision of ecosystem services.

Conservation — the intentional and sustainable management of the natural world and natural resources for current and future generations. This includes maintaining biodiversity, natural ecosystems, as well as functions and services of the environment, such as water filtration or nutrient cycling.

Cross-laminated timber (CLT) — an engineered wood product consisting of several layers of solid-sawn lumber laid and glued together in alternating orientations. There is growing interest in using CLT as an alternative to other structural building materials in construction projects, due to its strength and ability to utilize wood sourced from smaller diameter logs. Sustainability of CLT as an alternative structural building material depends upon the origin and forest management practices of wood used in its manufacture.

Diameter at Breast Height (DBH) — diameter at breast height is a standard way of measuring a tree’s diameter. DBH is typically measured at around 4.5 feet off the ground. DBH can help to estimate the volume, biomass and carbon storage of a tree.

Ecosystem services — benefits provided to humans by the natural world and healthy, functioning ecosystems. Healthy forests can provide ecosystem services such as food, air and water filtration, carbon sequestration, flood and erosion control, biodiversity, cultural value, recreation opportunities, and more.

Embodied carbon — greenhouse gas emissions arising from the production of a building material and/or the construction of building materials or an entire building. Carbon emissions through the life cycle of a product include extraction of raw materials, transportation, manufacturing, installation, maintenance, end of life of the material, disposal, and more.

Environmental justice — Environmental justice is the fair and equitable involvement of – and outcomes for – all people in environmental policies, practices, attitudes, and actions. This means all people having the same degree of protection from environmental harm, having safe and healthy access to the natural world, and having equal access to the decision-making process for environmental laws, regulations, and policies. Due in large part to our society’s decision-making spaces and the environmental movement being historically white-led, there have been unequal benefits of environmental protection with most benefits felt by white communities. This has led to a present-day landscape of environmental injustice where communities of color, Indigenous communities, and low-income communities bear the most burden of pollution, environmental degradation, natural disasters, and the climate crisis.

Environmental racism — Environmental policies, practices, or directives differently affecting or disadvantaging (whether intended or unintended) individuals, groups, or communities based on race or color. Environmental racism is one form of environmental injustice and is reinforced by government, legal, economic, political, and military institutions. For example, government funding for cleanup of toxic waste sites is frequently directed toward wealthier, white communities while these sites are disproportionately located in communities of color and low-income communities. Another example is redlining and segregation of neighborhoods, resulting in less greenspace and tree canopy cover in communities of color compared to nearby historically white communities.

Equity — fair access, opportunity, and advancement for all people. Justly providing people with what they need to lead healthy, full lives, based on their individual circumstances and lived experience. Achieving equity requires the recognition that different allocation of resources and opportunities are needed to reach an equal outcome for different individuals and groups of people, as a result of structural inequities and historic underrepresentation.

Mass timber — mass timber refers to a variety of engineered wood products used in construction, which are manufactured by combining dimensional lumber with adhesive or fasteners into panels and/or larger-dimension beams and columns. Examples of mass timber include cross laminated timber, mass plywood panels, glue laminated timber, and post and beam. Mass timber can be substituted for other structural building materials such as steel and concrete.

Mitigation — reducing the severity of something. Climate change mitigation refers to efforts to reduce or prevent emission of greenhouse gases. Climate change mitigation in forests focuses on maintaining and enhancing sequestration and storage of carbon in forest ecosystems, including through conservation, restoration, and improved forest management or climate-smart forestry practices.

Natural Climate Solutions (NCS) — conservation, restoration, and/or improved land management actions that increase carbon storage and/or avoid greenhouse gas emissions across global forests, wetlands, grasslands, and agricultural lands. NCS utilize natural systems to mitigate the effects of the climate crisis and store atmospheric carbon, and may include making investments and changing practices in the management of natural and working lands. Investing in NCS can simultaneously provide co-benefits and enhance many other ecosystem services. NCS in forests include improved forest management practices such as extended harvest rotations, avoided conversion of forests to non-forest uses, restoration, reforestation, and afforestation.

Prescribed fire (also known as prescribed burning) — a forest management tool that uses planned, controlled fire to manage the landscape. Prescribed fire is used to reduce fuels to decrease the risk of high severity wildfire, often coupled with mechanical thinning. Prescribed fire can also be used to aid ecological restoration, create of a mosaic of habitats, or support endangered species recovery. Burning is typically conducted outside of wildfire season and when temperature, precipitation, and wind conditions meet standards for safety. Indigenous peoples across North America have used cultural burning as a traditional landscape and natural resource management practice since time immemorial. 

Preservation — the protection of a natural environment from harmful human activities. It typically refers to setting aside natural areas with little or no human influence.

Procurement — the process of purchasing and sourcing products or services. In the context of climate-smart wood, sourcing may be guided by procurement policies and decision-making processes that emphasize social and environmental impacts. Depending on a company’s values and goals, they may consider factors such as the following in wood procurement: origin, equity considerations, landowner type, embodied carbon, environmental impacts, forest management certifications, forest management practices, etc.

Reforestation — the process of re-establishing forest cover in an area that was previously forested. Reforestation may be achieved by tree planting or natural regeneration.

Resilience — the ability of a natural ecosystem or community to retain its essential structure and function in response to disturbances or stresses such as fires or climate change, and to return to its pre-disturbance state.

Restoration — the process of assisting the recovery of an ecosystem that has been degraded, damaged or destroyed. Forest restoration initiates or accelerates a forest toward a historic or enhanced level of health, biodiversity, ecological processes, resilience and/or maturity. Restoration may involve actions such as removing invasive species, planting native species, reintroducing fire and prescribed burns, altering hydrology or landforms, or reintroducing native species.

Riparian forest — a forested area adjacent to a body of water, such as a stream or river.

Rotation age — the age at which a tree is harvested in a managed forest; the years of tree growth between timber harvest cycles in a managed forest.

Silviculture — the art and science of controlling the establishment, growth, composition, health, and quality of forests and woodlands to meet the diverse needs and values of landowners and society on a sustainable basis, such as wildlife habitat, timber, water resources, restoration, and recreation.

Stand — a contiguous grouping of trees sufficiently uniform in age-class distribution, composition, and structure, and growing on a site of sufficiently uniform quality, to be defined as a distinguishable unit. Silvicultural prescriptions or treatments are applied to stands in order to meet management goals.

Thinning — the selective removal of trees in a stand, reducing forest density towards the goal of improved growth and enhanced forest health, e.g. to reduce wildfire risk or to reduce mortality due to pests and disease. Thinning can be either commercial— producing material with a value equal or greater than the costs of the thinning, or non-commercial— producing material with value less than the costs of thinning. Non-commercial thinning achieves important management goals and often provides ecological value, e.g. restoration or reduction of wildlife risk.

Upland forest — a higher elevation forest, found upstream of wetlands and coastlines.

Wildfire — a fire in a wildland area, including forests and grasslands. Wildfires are a natural phenomenon in many fire-adapted ecosystems, which evolved with the regular disturbance of wildfire. However, human action has changed wildfire dynamics due a hundred years of wildfire suppression policies, coupled with climate change. The resulting build-up of fuels on the landscape, alongside hotter and drier conditions, has resulted in more frequent and intense wildfires in the American West.

Wildland Urban Interface (WUI, pronounced ‘Woo-ee’) — the geographic area where humans and human development meet or intermix with undeveloped wildlands. In this transition zone, communities and built structures are closer to vegetation and fuels that put them at higher risk of negative impacts due to wildfire, which may include forest fires, grass fires, or brush fires. Isolation of development in the WUI creates challenges to protecting human lives and structures from wildfire including limited access for evacuation and fire suppression.

Urban forestry — the planting, maintenance, care and protection of tree populations in urban settings. Urban forests are collections of trees or an area of tree canopy cover in a city or urban area.