Floodplain Forest Restoration: Progress, lessons learned, and new science from the Connecticut River Watershed

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1 Floodplain Forest Restoration: Progress, lessons learned, and new science from the Connecticut River Watershed D A V I D. P A T R I C T N C. O R G

2 Collaborators Christian Marks Connecticut River Whole System Team New Hampshire and Vermont Chapter staff Partners

3 Overview Why focus on floodplain forests? Restoration goals Restoration techniques Progress to date and lessons learned Emerging science Challenges, opportunities, and the road ahead

4 What is floodplain forest? Floodplain forests are forests that flood periodically!

5 But how much flooding do they need? Recorded data on about 15,000 trees at over 100 sites across basin Linked community structure to flooding frequency Floodplain forest average 4.5 days of flooding a year

6 Why focus on floodplain forests? Third Sunderland Island, Connecticut River, MA, 2015: Christian O. Marks

7 Ecological benefits of floodplain forest Green dragon (Arisaema dracontium) Rainbow Beach, Northampton, MA Vermont.gov

8 Provision of ecosystem services Flood storage Improved water quality Recreational value Improved fisheries Ecological and socio-economic resilience Hurricane Irene sediment mark, Elwell Island, Northampton, MA: Christian O. Marks

9 What we ve lost

10 Restoration goals

11 Goal of the Connecticut River Whole System Project (10-25 years) To enable the Connecticut River watershed to sustain a diverse range of healthy riparian, freshwater, and estuarine habitats and native species, while supporting vital human needs for energy, drinking water, and recreation

12 Floodplain forest goal (10 years) More than 5,000 acres of floodplain habitat have been restored, both vegetatively and hydrologically, protecting natural communities as well as cities and towns along the river from flood damages.

13 Priority floodplain clusters

14 Example of combined strategies in the Connecticut River Watershed

15 Restoration techniques Connecticut River Greenway State Park, Hadley, MA, April 16, 2015: Christian O. Marks Israel River Confluence, Lancaster, NH: Christian O. Marks

16 Strategies Natural regeneration Planting of seeds and seedlings (primarily silver and red maple and disease resistant American elm) Seedbed treatment such as tilling Invasive species control

17 Progress to date and lessons learned

18 Potter Farm At the confluence of the CT and upper Ammonoosuc rivers in the Maidstone Bends area 252 acres protected in 2010 Restoration of 14 acres of floodplain forest

19 Ballou property

20 Adaptive management

21 There is no one prescription for successful restoration

22 Natural revegetation Regenerating species included silver maple, eastern cottonwood, and box elder Success of natural recruitment influenced by: Sufficient seed rain (optimally source trees <50-m) Competition from existing grass (e.g. hayfields) Much higher regeneration in row crops compared with hayfields Higher regeneration at sites with fresh sediments from flooding Tilling hayfields followed by short-term row crop planting (~2 years) or planting larger seedlings (3-6 tall) can address competition with existing grasses

23 Success of planted seedlings Experimental planting of elm seedlings across 21 sites Survival varied among sites and years (range %, mean = 78%) Main sources of mortality were: Girdling by rodents (voles) Over-application of paint used to prevent girdling by rodents Ice scour Poor drainage Cutting by beavers Deer browse (issue in southern CT) Herbaceous competition Seedling size (larger = higher survival) Insect damage (primarily Japanese beetles)

24 Invasive species management Flood duration and depth influence abundance of most woody invasives Oriental bittersweet is most problematic Control can be expensive (50 person hours/acre) and is only likely to be feasible at priority sites

25 Emerging science Rainbow Beach, Connecticut River, Northampton, MA

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27 The road ahead Work to date has greatly increased our understanding of floodplain ecology and restoration A network of partners consider floodplain conservation and restoration a priority However, significant challenges still exist including: Balancing floodplain restoration with agricultural productivity Continued development in floodplain areas The resource-intensity of restoration Invasive species control Public perception of flooding and dynamic systems

28 Any questions?