Roadside Revegetation

PLANNING PHASE ONE: ORIENT
Revegetation Objective
Erosion Control
Water Retention
Visual Enhancement
Weed Control
Wildlife Enhancement
Cost Management
Function of Native Plants
Controlling surface erosion and thereby protecting soil and water quality is a high priority on road construction
projects. Native grasses, forbs, and other herbaceous plants can help meet this challenge, particularly
when they are accompanied by appropriate mulching treatments. Deep-rooted native trees and shrubs can
also enhance stability of cut and fill slopes.
Runoff from road surfaces and cut slopes concentrate water into ditches during rainstorm events, increasing
the amount of water that normally enters natural drainage ways. Practices that use native plants in the
design, such as constructed wetlands and bioretention swales, amended ditches and fills, filter strips, can
help retain much of this water on the project site, reducing the amount of sediments and road pollutants
from entering stream courses. The additional water increases the productivity of the established plants.
Vegetation is often used to enhance the aesthetic experience of the traveler. Wildflowers add beauty in
spring; deciduous trees change color in fall; and evergreen species stay green all year. Vegetation can also be
used to hide structures such as gabion walls or slopes covered by riprap.
Roadsides can be corridors for the transport and establishment of noxious or invasive weed species. Once
established, weeds are hard to eradicate and become seed sources for further encroachment. Revegetating
with desirable native species minimizes opportunities for problem species to establish.
Many roads intercept animal corridors. Designing native plantings into animal underpasses or overpasses
can make roads more permeable to wildlife. The presence of birds and small animals can be enhanced when
appropriate plant species are reestablished.
Advanced planning, an integrated approach, and the use of appropriate stocktypes and equipment all
facilitate successful and cost-effective revegetation.
4.3 GATHER PRE-FIELD INFORMATION
The revegetation plan is developed by obtaining an understanding of the road design and by
gathering pre-field information on the soil, climate, vegetation, and pollinators of the project
site. Much of this information can be obtained prior to visiting the project site. A good pre-field
review of information can make the time in the field more efficient and effective.
4.3.1 CLIMATE
Local climate plays a dominant role in the success or failure of the revegetation effort.
Knowledge of local climate factors can help delineate the appropriate revegetation units and
develop achievable DFCs. In later phases of the planning process, climate data will be used to
determine appropriate revegetation treatments.
Obtaining climate records from a variety of sources is the first step in conducting a climate
assessment. There are many sources of climate records for the United States (Figure 4-1). One
source is the Western Regional Climate Center website www.wrcc.dri.edu/coopmap that displays
the location of the National Oceanic and Atmospheric Administration (NOAA) Cooperative
Stations in the United States and provides historical weather data for most stations. Each
weather station has helpful graphics, such as spring and fall “freeze probabilities” (Figure
4-2) that can be used to determine the best dates for sowing seeds and planting seedlings.
Another available graphic is the probability of precipitation throughout the year, which can
be used to determine if supplemental irrigation is necessary (Figure 4-3). Finding a weather
station closest to the project site will be helpful in understanding the influence climate will
have on the project.
Roadside Revegetation: An Integrated Approach to Establishing Native Plants and Pollinator Habitat
39