Electronic Field Guide » Revegetation

Prepared by Patrick Drohan and Kevin Yoder (Ecosystem Science and Management)
 
Photo: Patrick DrohanThe development of drilling pads and associated infrastructure may require timber removal and later revegetation of disturbed areas.  A primary goal of revegetation is to establish a high percentage of a desired vegetation cover, which will prevent surface erosion and the establishment of invasive plants. In some areas, forest regeneration may be the ultimate revegetation goal, whereas in other cases, maintaining accessibility or even converting a former forested use to a new nonforest use may be desired.

The Penn State publication Erosion Control and Conservation Plantings on Noncropland has been a mainstay of public and state guidance for erosion and sediment control plans.  The publication recommends that for successful revegetation one should:

  • Carefully analyze any limiting site factors, both physical and chemical.
  • Select an appropriate combination of adapted plant species.
  • Select and use an appropriate set of establishment procedures consistent with the needs of the plant species to be seeded and the need to overcome any limiting site factors.
Before investing in soil testing, check for two of the biggest hurdles to successful revegetation: compaction and very rocky soils.  Compaction can decrease soil structure and porosity, inhibiting the movement of roots through the soil (to anchor aboveground vegetation) and their ability to extract water and nutrients.  Rocks replace soil, thereby limiting the availability of water and nutrients. Although some rocks may be beneficial in helping soils to warm up earlier in the spring, or by adding some rigidity to the soil, too many rocks cause problems for plant growth.  Extensive research on strip mine lands worldwide has shown that if compaction is avoided and the soil for the planting is deep enough and has a low rock volume, revegetation success is far greater.

Next, evaluate the topsoil stockpile and its potential extent and depth across the project site.  The topsoil that was stockpiled prior to site development should have been protected during the project via a cover crop of some kind.  Reapplication of this topsoil will result in a high fertility and soil organic carbon content across the revegetated site.  In addition, valuable soil organisms in this topsoil can help revegetation by enhancing the ability of plants to acquire nutrients and water from the soil.

Soil testing is an important  step in assessing which species might be best suited for revegetation.  However, be careful of interpreting a traditional agronomic soil test. In such soil test reports, amendment recommendations may be designed for agricultural crops and soil fertility levels not typical of sites across the Allegheny Plateau.  Many soils across the range of Marcellus development have a low soil pH (4-5 range).  A soil test report may recommend pH adjustment to 6.5, which could require more than 10,000 pounds/acre of limestone.  Therefore, if you're interested in amending the soil before planting, consider how large and fast a change in fertility or pH is needed and decide on amendment type and use accordingly. A consulting soil scientist or the county conservation district may be able to advise.

Unless a revegetation goal is specific to a nonnative species, successful revegetation results often use native species for final plantings.  Native species are often better adapted to the local climate and landscape characteristics. This may be especially important in areas that contain wetlands, or rare or threatened species. Sometimes native seed mixes are slower to establish, so it may be appropriate to use nonnative species during initial restoration to prevent surface erosion.  In such cases consider species that might be easy to remove/kill off by the time that native species are to be planted.

Specific recommendations for how to revegetate areas, based on slope, proximity to wetlands, etc., including species to plant and species to avoid, have been created by Penn State and the Bureau of Forestry. Contact the nearest PA Department of Conservation and Natural Resources district forester for information from DCNR. New recommendations specific to soils across the range of landscape spanning the Marcellus shale deposit are being developed by Penn State and nurseries around the state. In the meantime, see the Penn State publication Erosion Control and Conservation Plantings on Noncropland.