Forests represent one of Maryland’s most important natural resources, critical to its economy, sustainability, health and identity. Forest conservation and tree planting are central strategies to achieve the goals laid out in the 2014 Chesapeake Bay Watershed Agreement (CBWA) and are reinforced in many parts of the Maryland legal code. To monitor forest and tree canopy cover status and progress toward its commitments, the Maryland General Assembly enacted legislation (House Bill 991) in 2021 requiring a Technical Study of Changes in Maryland’s Forest Cover and Tree Canopy.
This study, with results presented here, improves Maryland’s statewide inventory of forest and tree canopy cover, assesses near and longterm change and assesses the effectiveness of forest and tree programs operating in the state. Notably, this study makes use of a newly released, innovative, very high-resolution (1-m) land use and land cover dataset for the Chesapeake Bay Watershed used for the first time to monitor individual trees within and outside forests across Maryland. This is complemented by moderate-resolution satellite imagery, ground observations and other research to generate insights on the status of tree canopy cover in the state. Service Forest Inventory and Analysis (FIA) program and the Chesapeake Bay Program Office (CBPO).
When tree canopy outside forests is included, the state’s total tree canopy covers an estimated 3.095 million acres (CBPO). Percent forest cover estimates range from 39-42% of the state’s total land area, depending on the dataset and approach used (FIA, CBPO). Findings from three independent data sources (FIA, CBPO, and the National Land Cover Dataset or NLCD) agree on similar trends in Maryland’s forests. Forest area has shown a slightly decreasing trend over 5- and 20-year intervals but with a trend toward stabilization in the past 10 years (-0.14% annually from 2013-2018; -0.23% annually from 1999-2019). The decrease in forest cover has been offset somewhat by an increase in tree canopy outside forests, resulting in a more modest decrease in the total tree canopy (-0.077% annually) (Table ES-1) (Task 1).
Despite the slightly decreasing, yet now stabilizing, trend, the state’s tree canopy has been remarkably stable given considerable increases in human population over the same period (880,738 people or nearly 17% growth from 2000-2020). Maryland’s forests cover 2.448 to 2.566 million acres of the state’s land area, according to the USDA Forest Table ES-1. Forest and tree canopy extent estimates from key data sources. This represents an opportunity for the state to achieve a net gain of forests and tree canopy in the near future, given continued investment in forest conservation measures and tree planting.
For more information, and to view the ArcGIS StoryMap, please visit the Chesapeake Conservancy’s webpage
here.
