Massachusetts Dept. of Conservation & Recreation: Protecting Riparian Zones with a Focus on Stream Crossings

Staff from the Forestry Division of the Massachusetts Department of Conservation and Recreation used the Adaptation Workbook to consider climate change risks and management opportunities for timber sale on state forest land. This project focused on stream crossings on the main access road used for forest management activities.

Project Area

The main access road being used for a timber sale in the South River State Forest has multiple culverts for streams that enter in the Deerfield River, many of which have failed. The focus of this project is to remove the failed culverts and replace them with an economical bridge alternative that will meet state and local environmental regulations while also taking into account increased water flows due to climate change.

Management Goals


The overarching intent of this project is to protect water resources during a timber sale. One management goal for this project is to replace the failing culverts with new, cost-effective infrastructure, which would include designing a bridge that meets necessary criteria and can be paid for with revenue from the timber sale. Another management goal is to restore vertebrate and invertebrate passage in the riparian zone by creating more natural stream bottom conditions and increasing the length of unfragmented stream segments. A third goal is to protect multiple riparian zones during forest management activities, with objectives related to maintaining  moist conditions and adequate stream shading, increasing tree species diversity, and controlling invasive exotic and undesirable plants

Climate Change Impacts

culvert under a woods road in the early spring
The riparian zones within the South River State Forest sourced by multiple seeps and small wetland areas. The soils are of the rich mesic type and are highly erodible. Given the interest of improving stream crossings to protect water resources, the foresters working on this project identified the following climate change effects as being the most important at this site:
This region is expected to experience warmer temperatures, but without an increase in precipitation during the summer months. An increase in soil moisture deficit or drought could stress vegetation in the riparian zone, particularly sugar maple.
Drier conditions may also lead to hydrophobic soil conditions, which would increase runoff if rain falls on these soils.
Increases in winter precipitation and a warming climate than favors rain over snow could increase streamflow during the winter months. Reduced snowpack and increased winter runoff may reduce groundwater recharge.
Intense precipitation events are expected to become more frequent. These events can increase scouring of the stream channel and have the potential to exceed "bank full" conditions.

Challenges and Opportunities

Climate change will present challenges and opportunities for accomplishing the management objectives of this project, including:


Conditions may become wetter during the period when operations are likely to occur, which would increase the potential for soil erosion or damage and limit the success of the project.
Climate change will accelerate the spread of hemlock woolly adelgid, which will impact an important species in the riparian zone.
Warmer temperatures or more open canopy conditions as a result of stress on the overstory trees may allow for invasive and undesirable species to increase in the understory.


The proposed activities reduce risks to the site from extreme precipitation events and other changes in climate. Anticipated changes in climate only increase the need to implement these activities sooner rather than later.

Adaptation Actions

The DCR forester responsible for preparing this timber sale used the Adaptation Workbook to develop identify how the proposed timber sale could help the area to adapt to climate change. These actions largely centered on increasing the resilience of the stand by encouraging diversity and complexity.

Stream crossings
1.3. Maintain or restore riparian areas.
Remove failing culverts and replace with bridges. Ensure stream connectivity and a naturalized stream bottom.
Riparian forest
1.4. Reduce competition for moisture, nutrients, and light.
2.2. Prevent the introduction and establishment of invasive plant species and remove existing invasive species.
Control of invasive plants using herbicides pre- and post-harvest.
5.1. Promote diverse age classes.
5.2. Maintain and restore diversity of native species.
9.5. Disfavor species that are distinctly maladapted.
Use of uneven-aged silviculture to promote age and species diversity. Remove hemlock and ash because of susceptibility to insect pests and encourage regeneration of a diversity of tree species.
5.2. Maintain and restore diversity of native species.
5.3. Retain biological legacies.
Maintain at least 50% of the basal area along streams, per current regulations.
5.2. Maintain and restore diversity of native species.
9.1. Favor or restore native species that are expected to be adapted to future conditions.
9.2. Establish or encourage new mixes of native species.
Consider the use of artificial regeneration to shift the composition in the riparian zone, using species such as northern red oak, hickory species, or American chestnut.


Project participants identified several monitoring items that could help inform future management, including:
Development of bridge alternative with natural stream bottom conditions.
Bridge design and construction cost limitations (i.e., maintain bridge costs at less than 40% of timber sale income).
Length of natural stream bottom.

Project Photos

Click to enlarge photos

Culvert in the project area.

Project Documents

Next Steps

This project will be harvested in the next few years.

Learn More


Flooding, Lowland/ bottomland hardwoods, Upland hardwoods, Water resources

Last Updated

Friday, April 21, 2017