Oh, deer!

Pittsburgh's parks are home to thousands of plants, a robust tree canopy, and a variety of wildlife, including deer.

Recently, discussions have amplified from Pittsburghers across the region regarding these wide-eyed creatures. And as cute as deer can be, they threaten the ecological health of Pittsburgh's parks.

Did you know that in city parks, deer populations are several times higher than a healthy population would expect? For example, according to a 2010 United States Department of Agriculture study, Pittsburgh's city parks had approximately 60 deer per square mile on average. In contrast, a healthy density is about ten deer per square mile.

Unfortunately, high populations of deer can have severe, long-lasting impacts on the health of the forest ecosystem. Physical damage from deer occurs through two primary mechanisms:

• Direct browsing: The eating of leaves and new growth.
• Buck rubbing: Damage to tree bark from bucks rubbing their antlers on small trees during the mating season. 

This damage reduces the ability of forests to regenerate. Without forest regeneration, our natural areas will provide dramatically reduced ecosystem services, such as stormwater interception, erosion control, air purification, and temperature mitigation.

At the Parks Conservancy, we spend a lot of time and resources responding to pressure from the abundant deer population in Pittsburgh's parks.

Actionable steps taken by the Parks Conservancy include:

• Replacing plant material that is damaged or consumed by deer
  • Perennials in the gardens that are eaten
  • Landscape trees that are killed by buck rub
  • Restoration trees that are eaten or killed by buck rub
• Physical protection from deer needs to be purchased, installed, and maintained
  • Wire cages around trees or shrubs in gardens
  • Deer exclosures in woodlands
  • Bark-guards on landscape trees

In 2019, the Parks Conservancy built a deer exclosure in the Clayton Hill area of Frick Park that has been able to grow "un-browsed" for the last three summers (2020-2022), which has led to a remarkable difference. If you'd like to learn more about the Parks Conservancy's ecological restoration efforts, visit Clayton Hill to explore the visible difference in forest and understory regeneration without the pressure of deer browsing on native species.

Additional deer exclosures are located in Emerald View Park, including Grandview, Greenleaf, and Mt. Washington Park areas.