US Fish and Wildlife Service and partners: Palmerton Zinc Superfund Site

This project involves the reforestation of a 1000-acre, ridge-top area denuded by smelter emissions. Climate change was considered in the selection of tree species for planting.

Project Area

The Palmerton Zinc Pile Superfund Site covers 1,000 acres on a ridgetop in the Ridge and Valley Province of Pennsylvania. This former zinc smelting facility has been a source of metal contamination since the beginning of the 20th century, and the area has been denuded by smelter emissions. Several federal, state, and local organizations have partnered to clean and restore this Superfund site.

Management Goals

The goal of this project is to establish a central oak-pine forest on the site that will be resilient to climate change and other impacts. The forest will also include blight-resistant American chestnut, restoring a species that was once part of forests in this landscape. Measurable objectives include:

  • 50 oaks and chestnuts saplings established by year 10
  • 35 saplings of native woody species other than oak and chestnut by year 10
  • 70% canopy cover by year 40, with no area having less than 40% cover
  • Minimize invasive species competition (<5% of cover)
  • Eradication of spotted lantern fly

Challenges and Opportunities

This area currently lacks vegetation in many areas, and climate change has the potential to affect the reforestation effort in several ways. Tree species that are planted will be affected by changes in the climate. Many tree species are expected to have decreases in habitat suitability, and so some tree species that are planted may not do well over the long-term. Warmer and drier conditions may create additional stress for trees that are planted through reforestation efforts, as well as remnant trees that are present on the site. Water stress is likely to make trees more susceptible to insect infestation; this is of particular concern at this site because of an infestation of the spotted lantern fly that needs to be controlled. Invasive plant species also pose significant challenges at this site because the site is disturbed, and climate change may give some of these species a competitive advantage.

Adaptation Actions

Project participants used the Adaptation Workbook to develop several adaptation actions for this project. Because this project is reforesting a denuded site, there are opportunities to create forest communities that are well-adapted to future conditions. Managers at the site are considering how to factor climate change considerations into species selection, which includes planting resident species (i.e., those that are currently present locally) expected to be tolerant of predicted conditions, as well as seeding and planting more southerly species that are projected to expand north. If properly implemented, the forest that grows on this site will be uniquely suited to future conditions and act as a seed source for range expansion.

Entire site
5.2. Maintain and restore diversity of native species.
Introduction of blight-resistant American chestnut
Planting a diverse mix of hardwood seedlings and saplings as well as fruit-bearing shrubs in resource islands and seed surrounding areas with conifer seeds
1.1 Reduce impacts to soils and nutrient cycling.
Application of lime and fertilizers
Reseed any bare ground areas
2.3. Manage herbivory to promote regeneration of desired species.
Install fencing about hardwood resource islands
3.2. Establish fuelbreaks to slow the spread of catastrophic fire.
Plant cool season grasses around fenced tree islands
5.3. Retain biological legacies.
Retain pockets of trees that survived smelter pollution
6.1. Manage habitats over a range of sites and conditions.
Plant hardwood tree and shrub resource islands spaced across the ridge from the SW to NE corners of the site. Place some islands at the top of the ridge top, some on south-facing slope, and some on north-facing slope.
9.2. Establish or encourage new mixes of native species.
Distribute seeds and plant seedlings and saplings from species at northern extent of range or further south if they are predicted to have northward range expansion.
9.1. Favor or restore native species that are expected to be adapted to future conditions.
Plant or seed resident species that are tolerant of predicted future soil, moisture, and temperature conditions.
10.3. Realign significantly disrupted ecosystems to meet expected future conditions.
Replant any disturbed or high mortality areas with species expected to tolerate changing conditions at year 10 and in each subsequent decade.
2.1. Maintain or improve the ability of forests to resist pests and pathogens.
Monitor gypsy moth infestations and spray approved control agents when necessary
Remove all female and most male tree of heaven which is the preferred host for spotted lantern fly while maintaining small clusters of male trees as traps
4.1. Prioritize and maintain unique sites.
Protect north-facing coves
7.2. Maintain and create habitat corridors through reforestation or restoration.
Space hardwood islands along ridge. Seed conifers in between islands.
2.2. Prevent the introduction and establishment of invasive plant species and remove existing invasive species.
Remove invasive plant species: tree of heaven, butterfly bush, and Japanese stiltgrass


Monitoring will be used to evaluate whether the site managers have successfully established a climate-adapted forest while meeting the reforestation performance measures for stand density, diversity, and vegetative cover. To do this, monitoring will track seedling/sapling survival by species, vegetative cover, and the proportion of at-risk species at appropriate intervals as the forest is established and matures. Tracking invasive plant and insect species will be also be critical to reducing non-climate stressors that affect ecosystem function.

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Insect pests, Invasive species, Diseases, Upland hardwoods, Assisted migration, Planting, Restoration

Last Updated

Tuesday, May 22, 2018