Field Notes: Bottomland Forests and Flooding

By Scott Bachman, senior area forester

I will confess, when I moved to Isle of Wight County as a much younger forester, I was concerned about the “swamps” and how I would ever work in this environment.  Three decades later I have learned to enjoy the bottomland forests and to appreciate the ecosystem services they provide.

One such service is floodwater storage and energy dissipation.  In mid-February this year, much of the Commonwealth experienced significant rainfall.  VDOF personnel in the mountains were tasked with missions to assist with flash flood recovery.  In the coastal plain of Virginia, we received similar rainfall but no significant flash floods.  As you undoubtedly guessed, that is because we do not have mountains!

Nevertheless, water still must run off the land. An inch of rain on an acre of land equates to a bit more than 27,000 gallons.  Where does it all go if it cannot run off rapidly?  It spreads out into our floodplains!

Virginia has two types of floodplains: red river bottomlands and blackwater river bottomlands. Red rivers have their headwater in the Piedmont or above.  Their waters contain clay sediments and tend to be brown or “red”.  The James River is one. Blackwater rivers have their headwaters in the coastal plain.  The waters of in these rivers tend to be dark and tannic, nearly like dark tea.  The Blackwater River in Isle of Wight is one.  There are implications for fish and aquatic systems, but that is a post for the Virginia Department of Game and Inland Fisheries.

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There is an incredible amount of energy held in moving water, especially floodwaters.  We are reminded, when flooding is eminent, to never try to drive or walk across a flooded road.  In flash floods, this energy is expended in uprooting trees, sweeping away cars and homes, and washing out bridges and culverts (thus the need for proper best management practices in timber harvest operations.)  In the wide, flat floodplains of the coastal area, this water energy is stored and slowly released by spreading out over the flat lands adjacent to the river bottoms.

The friction from the water striking the buttressed roots of the wetland-adapted trees slows the water, dropping sediment and releasing energy.  This water, clearer of sediments, will slowly leave the river bottom and eventually reach an estuary before finally making it to the ocean.  These can be slow-moving, long-duration flood events.

Unfortunately, some of our oldest towns and cities are built close to these floodplains, as they were the superhighways of the earlier times.  When the floodplains are not able to hold all the rains, these communities can be inundated with flood waters for extended periods.

It is important for us to recognize the ecosystem services that our forests provide.  Most of us know about the more obvious services forests provide – clean air, wildlife habitat and carbon sequestration.  Floodwater storage and sediment reduction may be other services that you had not considered.

VDOF Pine Projects Continue Despite Unusual Circumstances

In late March, VDOF personnel completed a longleaf pine grafting project at the New Kent Forestry Center (NKFC). The longleaf pine seed orchard at NKFC has been developed in response to a need for consistent crop production to support restoration efforts for this diminished species.

Read more: From the Brink! The Effort to Restore Virginia’s Native Longleaf Pine, 2014 Status Report

This year during a three-day period, a crew collected and grafted 97 scion. Scion are approximately five- to eight-inch buds cut from older, established longleaf trees in the orchard.  By top-grafting the scion (explained below with photos) onto established three- to four-foot tall root stock, VDOF’s tree improvement team can achieve two things:

  • Create an orchard selection from a known parent – a successful graft will be an exact duplicate or clone of its parent.
  • Stimulate early flower production – grafted trees will produce cones and seed sooner than non-grafted trees.

The longleaf pine project is an attempt to preserve the genetics of the very few (<200) remaining Virginia-native longleaf pines. Research has found that these trees are uniquely adapted to the climate and soil conditions here at the northern limit of their range. Because grafted trees are clones of their parents, this process allows VDOF to save as much of this genetic base as possible for future seed/seedling production.

Longleaf Pine Grafting Process in Photos

 

Bitoki
Ones Bitoki (tree improvement manager) has cut the terminal bud from the root stock and grafted a scion in its place.

 

Gaston
Dennis Gaston (eastern area state forests manager) has wrapped a grafted scion with rubber grafting bands which will hold everything in place until it begins to grow together.
Creighton
The new grafts are first wrapped with rubber grafting bands, which was noted in the previous photo.  Next they are wrapped with parafilm which helps to seal the graft and keep out insects or any elements which may harm the graft.  Finally, it is wrapped in aluminum foil, adding another layer of protection. In this photo, Jerre Creighton (research program manager) is wrapping a graft in foil.

 

Schroering
We tag each graft with the parent tree number and the grafting date for our records.  In this photo, Jim Schroering (southern pine beetle and longleaf pine coordinator) has tagged a completed graft.

 

Wrapped Graft
This photo shows a completed graft wrapped with the rubber bands and parafilm.

 

Successfull 2019 graft
This photo shows one of VDOF’s successful grafts that was done in 2019.

Another Pine Project at NKFC

Grafting wasn’t the only work that took place at NKFC during this time.  During March, Jeff Stout (tree improvement technician) removed trees from the third cycle loblolly pine orchard that have been cut or “rogued” from the orchard.

As the orchard matures, trees that rank lowest in productivity scoring are removed, which in turn increases the overall productivity of the remaining families due to open pollination of all the trees throughout the orchard.

This orchard is not managed like a pine plantation because the desired outcomes are different.  We reduce the area between trees as they grow to reduce competition so the orchard trees will grow outward rather than upward (which would be preferable in a pine plantation.) The wider the trees are, the more limbs they have and thus more cone production.

Stout
Jeff is removing one of the cut orchard trees using an articulated loader with clamp attachment.

Field Notes: Sounds of Spring

by Ellen Powell, conservation educator

The flush of green suffusing our woodlands isn’t the only signal that spring is here.

If a daily dawn chorus wakes you this month, it likely includes our state bird, the northern cardinal (Cardinalis cardinalis). This species is a bit unusual, in that both males and females sing, providing a familiar soundtrack in woodland edges and thickets statewide.

Learn more about cardinals and listen to their songs.

Ivy Creek view 1
Ivy Creek.

One of the first warblers to return to central Virginia woodlands is the Louisiana waterthrush (Parkesia motacilla). Listen for it’s clear-noted song and watch for it foraging along the edges of woodland streams like the one pictured on the right.

See and learn more about the Louisiana waterthrush here.

Birds aren’t the only singers in the spring woods. Frogs and toads gather in shallow wetlands and ponds to mate. The more males in a breeding chorus, the more likely they are to be heard by potential mates. Late March is an excellent time to hear a chorus of American toads (Anaxyrus americanus), especially on cloudy days.

Listen to ethereal trills of the American toad.

 

 

Credit, Photo of Northern Cardinal: Jessica Bolser/USFWS

Field Notes: Good Green, Bad Green

By Ellen Powell, Conservation Educator

The calendar and the plants agree – spring has arrived in central Virginia!

Patches of green among the leaf litter mean spring wildflowers are making their annual appearance. Often called “ephemerals,” for their short-lived bloom time, those in flower this week include pennywort (Obolaria virginica), star chickweed (Stellaria pubera) and wild geranium (Geranium maculatum).

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Pennywort (Obolaria virginica).
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Star chickweed (Stellaria pubera).
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Wild geranium (Geranium maculatum).

Unfortunately, the shrub layer of many hardwood forests reveals a “dark side” of spring. Quite a few invasive plants green up earlier than native shrubs. These include wineberry, barberry, privet, multiflora rose and autumn olive.

Autumn Olive
Autumn olive (Elaeagnus umbellata).

The pale green plants in this picture are autumn olive (Elaeagnus umbellata), a non-native invasive shrub that often displaces the natural shrub understory. If you smell something cloyingly sweet while hiking, the culprit may be autumn olive in bloom. The tiny, tubular flowers will make way for red berries this summer.

A silver lining? The berries are high in lycopene and antioxidants, and they’re edible. So, pick as many as you can, before the birds spread them even farther!