Changes in timberland area by stand-age class in Pennsylvania
About Pennsylvania Forests
Pennsylvania's forested landscape has undergone significant changes over time. Currently, the state has approximately 16.6 million acres of forest land (as of 2019), which is a slight decrease from 16.9 million acres in 2014. The age structure of these forests has important implications for wildlife habitat, timber resources, and ecological processes.
Forest age refers to the time since the last major disturbance (like clear-cutting or natural events) that initiated the current stand of trees. Different forest age classes provide varying habitats for wildlife and have different ecological characteristics.
*Error bars represent a 68 percent confidence interval. Data source: USDA Forest Service Forest Inventory and Analysis Program.
Age Class Distribution (2004)
Age Class Distribution (2019)
Major Forest Types in Pennsylvania (2019)
Forest Ownership
Forest Cover Change (1955-2019)
Total Forest Area in Pennsylvania (1955-2019)
Changes in Older Age Classes (61+ years)
Pennsylvania's Forest History
Pennsylvania's forests have undergone dramatic changes since European settlement:
Pre-1800s: Almost completely forested with old-growth trees
Late 1800s: Widespread deforestation for lumber, fuel, and agriculture
Early 1900s: Beginning of forest conservation efforts
Mid-1900s: Forest regrowth as agriculture declined
2000s: More mature forests but increasing forest fragmentation
Definitions of Forest Age Classes
0-20 years: Young forest with abundant understory vegetation
21-40 years: Early successional forest with developing canopy
41-60 years: Maturing forest with closing canopy
61-80 years: Mature forest with more complex structure
81-100 years: Late mature forest with developing old-growth characteristics
100+ years: Old forest with complex structure and diverse habitats