Forestry for Water Quality

The results are in, and the 2019 annual Silviculture Best Management Practices (BMP) Implementation Monitoring Report shows that the logging industry and timberland owners continue to excel at protecting Virginia’s water resources. Forests are essential to clean, healthy drinking water and watersheds, and sustainably-managed forests are the most effective land cover for protecting water quality.  Continue reading Forestry for Water Quality

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.

Field Notes: A Rare Tree Adventure

By Emerald Ash Borer Coordinator Meredith Bean

It was August 27, very late in the season to be treating ash for protection against the emerald ash borer (EAB), and we were about to do just that. With the state’s most active “Big Tree hunter” as our guide through the swamps of Cypress Bridge Natural Area Preserve, we hopped into canoes to find the largest Carolina ash trees on record in Virginia. Along the way, we drifted through lily pad patches and marveled at the resilience of swamp trees as they survive in feet of water year-round.

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Lara Johnson (urban and community forestry program manager) and Byron Carmean (champion tree hunter) canoeing among the water tupelos and cypresses.

With a little searching, we finally found the two champion Carolina ash (Fraxinus caroliniana) trees and immediately started measuring and treating. They must have been thirsty because they took the insecticide right up! Each tree may not be larger than 20 inches in diameter nor look nearly as remarkable as their neighbors, but they are just as critically endangered as the giant cypresses surrounding them.

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Meredith Bean (emerald ash borer coordinator) and Meghan Mulroy (community forester) treating the #1 state champion Carolina ash with emamectin benzoate via microinjection.
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Lara Johnson and Byron Carmean with the champion Carolina ash post-treatment.

While emerald ash borer has not yet been confirmed in Southampton county, proactively treating specimen ash trees is the best method to ensure their survival for the inevitable day they are attacked. To find out more about this destructive pest and VDOF’s EAB program, please see our StoryMaps.

Many thanks to the Department of Conservation and Recreation Natural Heritage Program for preserving this ecosystem and allowing us to treat the Carolina ash, and to Byron Carmean for the awe-inspiring tour!

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Byron Carmean standing in the hollow trunk of a healthy cypress.
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Knees of a giant cypress that are taller than Lara Johnson on dry land!

More Information

Big Tree Registry

DCR Natural Heritage – Cypress Bridge

VDOF Emerald Ash Borer StoryMaps

Carolina Ash Characteristics

Field Notes: A Tale of Cypress Trees and Floods

by Senior Area Forester Scott Bachman

Earlier this summer my co-workers and I were finally able to get out and measure a harvest in Southampton County.   The harvest had been in a stand of bottomland hardwoods.  The landowner retained a riparian buffer on both sides of the stream channel during the harvest to protect the water quality of a significant tributary of the Blackwater River. The Blackwater River is a designated Scenic River in Southeastern Virginia that eventually flows past the City of Franklin and into North Carolina.  It is a substantial source of fresh water for the Albemarle Sound.  This buffer qualified the landowner to take advantage of the Riparian Buffer Tax Credit Program.

Heavy spring rains had finally stopped and the water had finally subsided enough to walk the harvest area.  We headed out to the tract early in the morning to beat the fast-rising temperature.  Unfortunately, we were not early enough!

On-site, our team split up since the harvest was on both sides of the broad bottomland flat.  I took the far side of the property.  After a half hour or so, I began to curse my choice of where I was working.  It was hot and occasionally flooded.  I even scared a great blue heron out of the harvest area.  You know it is a wet area when the great blue herons are hunting in it!

About that time it dawned on me how lucky I was that this was my office for the day!  I had just seen a great blue heron up close.   Up on the highlands of this tract there were a couple bobwhite quail whistling, trying to court the favor of a female.  Around my feet were a myriad of frogs jumping from one puddle to another.  Signs of life were everywhere around me.

People may not think about a harvested area as a nursery but it surely is.

Bottomland Harvest

 

Not only were signs of animal life abundant in the rapidly drying rich soil, but under my muddy boots were thousands of tiny bald cypress seedlings Cypress on dry site along with regenerating grasses, forbs and other tree species.

Bald cypress has an interesting method of recolonizing a disturbed wet flood plain.  You might assume that the seedlings result from seed that fell from a tree directly over the spot that is now supporting the carpet of cypress seedlings.  That may happen in some cases, but cypress trees drop their seed in the late fall and early winter when water levels at their base may be high and rising.  Bottomland forests are not typically harvested during seed fall due to this high water level.  Where could all this seed come from if it did not come from trees that were on the site?

Cypress seed is not heavy.  As the fall flood waters creep into the bottomland areas it carries the seeds of cypress trees growing in the watershed.   During the flooding season, the seed will float downstream or perhaps even upstream!  As spring fades to summer the water level in our swamps drops.  Bald cypress seeds simply float with the floods until waters recede and they are deposited on the freshly laid layer of silt! During years of very high water, cypress seeds can be carried well up into what might be considered “high land” Cypress Regeneration  These dryland cypress may have more competition from other trees but if they get sufficient sunlight, they will do well and eventually become spectacular members of the forest canopy.

Bald cypress seedlings that develop on the wet soils in swamps must be able to grow tall enough to be higher than the flood waters when they return in the winter.  Because of this, cypress trees are very fast growing trees in their youth.  The Virginia Department of Forestry nursery grows and sells bald cypress seedlings.  These trees are one-year-old seedlings.  When they arrive on your doorstep they are often more than three feet tall! The seedlings I saw were, at most, probably only two months old.

Living in Southeastern Virginia, I have developed a fondness for bald cypress.  The feather-like foliage is beautiful in the summer and striking in fall color.  As a gymnosperm species it is unique in that it drops its foliage in the winter.

Mature Cypress

 

Bald cypress is an excellent yard/urban tree.  In dry settings the tree will not develop the characteristic knees found on trees in its native wetland site.  It is very tolerant of poor soils and soil compaction, relatively pest free, rot resistant and fast growing.   The fine feathery “leaves” are easy to clean from yards with either a rake or blower.  Just make sure you have plenty of space when planting this tree.  Cypress can easily top 80 feet tall and live for hundreds of years!