Land cover can generally be considered as the natural vegetation, water, exposed rock and soil as well as human-constructed or altered surfaces of the earth.
Land Cover changes with land use. Cuyahoga County encompasses nearly 460 square miles with the following land uses (2019 data): Residential 53%; Parks & Open Space 15%; Industrial 9%; Commercial 6%; Institutional 5%; Transportation & Utilities 3%; Vacant 9%.
The effects of disrupted landscapes can often be seen along stream banks and the ratio of natural, vegetated land cover to disrupted hard and impervious surfaces can impact the stability of the stream bank and aquatic life within streams of that watershed. A large amount of impervious land cover within a watershed results in water runoff that is not absorbed when natural vegetated land cover is absent. The amount of contiguous acreage and its land cover or use can affect the health of animal habitat. For example, large patches of heavily forested areas can support wildlife habitats and a species’ range better than the same acreage of segmented, smaller areas.
Tree canopy is the layer of leaves, branches, and stems of trees that cover the ground when viewed from above. The Cuyahoga County Planning Commission conducted an urban tree canopy assessment for Cuyahoga County and published the results in 2013. This assessment was updated, and a new report published in 2019.
The assessment results indicate the amount of tree canopy, the potential for expanding the tree canopy, and the canopy changes measured in the time period between these two studies.
The studies also map and display areas for potential tree canopy where tree canopy does not currently exist. These areas could potentially support new tree canopy and include vegetated, bare, and paved surfaces. The potential for tree canopy could be relatively high in areas with large parking lots.
The maintenance of existing trees is important to the health of the tree and its canopy. The Ohio Department of Natural Resources Division of Forestry has demonstrated that, over time, maintaining existing tree health is more cost effective than planting new trees. The Urban Tree Canopy Assessment studies recommend the adoption of a regular, funded maintenance plan for trees in a community. Additionally, establishing a tree canopy goal is crucial for a community seeking to improve its green infrastructure. The National Forest Service recommends a tree canopy goal of 41% for urban areas, and a goal of 50% or greater in stream corridors and headwaters areas.
The land cover layer in the Greenprint Viewer was developed as part of the County’s 2019 Urban Tree Canopy Assessment (UTC). This high-resolution land cover is far more detailed than traditionally available sources. Tree Canopy quantities, or “metrics,” were extracted at various geographic levels.
Importance and Value
Tree canopy is the layer of leaves, branches, and stems of trees that cover the ground when viewed from above in mid-summer. Shrubs and small trees (less than eight feet in height) are excluded. Tree canopy is detected and measured over both natural surfaces and structures such as buildings, sidewalks and parking lots.
- Trees and soils function together to reduce stormwater runoff. Trees are living water towers and they rapidly soak up stormwater.
- Trees help minimize flooding and improve water quality.
- Trees are critical to climate resilience. They help moderate temperature as windbreaks, through shade, and through evapotranspiration, the transport of water plants to the atmosphere, thus reducing the urban heat island effect occurring in city centers.
- Trees remove many pollutants from the atmosphere, including nitrogen dioxide (NO2), sulfur dioxide (SO2), ozone (O3), carbon monoxide (CO), and particulate matter (PM) of 10 microns or less (PM10).
- Trees reduce greenhouse gases through the uptake of atmospheric carbon.
- Trees provide diverse habitat, food, and nesting sites for a wide variety of wildlife.
- Contiguous areas of vegetated land, particularly woodlands, are more beneficial than individual fragments for habitat and provide a wildlife buffer between habitat and residential and commercial areas .
Recommendations for Communities and Landowners
- Protect the existing tree canopy, especially in stream headwaters areas.
- Adopt a tree plan that includes tree planting, maintenance, and tree removal standards, guidelines and policies.
- Adopt a tree replacement policy to ensure that whenever a tree is removed, it will be replaced.
- Consider a tree removal permit system.
- Consider a recompense policy for historically significant or other identified specimen trees in case of harm.
- Adopt development guidelines that require and define tree placement for new construction activities.
- Fund a municipal tree maintenance budget.
- Retrofit parking lots with trees or make tree islands and street trees a part of city code or design guidelines.
- Encourage, and consider incentives, for private property owners to plant and maintain more trees, especially in privately held plant-able areas.
- Develop citywide plans and practices to minimize the spread of tree diseases and tree killing insects such as the Emerald Ash Borer and Asian Longhorn Beetle and replace affected trees with a diverse palette of resistant species.
- Adopt landscaping design standards regarding trees for commercial and industrial properties.
- Ensure that landscape design and planting requirements are environmentally and species appropriate to optimize the health and long-term survival of new plantings.
- Identify areas which could expand or connect forest patches and determine the practicality of planting more trees in these areas.
- Develop programs that educate residents on tree stewardship and provide incentives for tree planting and maintenance of forest patches on private property.
Resources for More Information
- U.S. Forest Service Urban and Community Forestry – resources and publications on trees, insects and diseases, Greening your Community and more.
- Forest Service Open Space Conservation Strategy – outlines national priorities to help the Forest Service be a more effective partner in open space conservation to ensure that forests and grasslands across the landscape can continue to provide valued services and benefits. Includes a downloadable report.
- Landscaping for Biodiversity with Ohio Native Plants: A Species Guide for Plantings
- Cuyahoga County Urban Tree Canopy Assessment and 2019 Update – visit the site and a more complete documentation of the land cover analysis performed by the University of Vermont’s Spatial Analysis Laboratory for information including:
- A Downloads section provides downloadable GIS and spreadsheet data for several levels of geography, as well as links to live web map services. Each of the downloadable data sets contains significant detail on acreage and percentages of all the available land cover measures.
- For background on the topic of UTC Assessments, see the Conclusions section which include links to additional resources.
- The Cleveland Tree Plan – Goals and action steps
- ODNR Division of Forestry Urban Forestry – Community Assistance programs and resources
- Tree City USA – a program of the Arbor Day Foundation that is administered in Ohio by the Ohio Department of Natural Resources Division of Forestry.
- Cuyahoga County Climate Change Action Plan – an effort to set targets for greenhouse gas emissions reductions, implement and track actions to meet targets, and adapt to climate change across Cuyahoga County