Thursday, November 17, 2016

Fall Fires of 2016

Since September, we have been watching the woods gradually dry up.  There has been an audible change trekking to and from our sites throughout the mountains this fall.  The gentle shuffling sounds of walking on leaves and sticks has become a loud crunch, crunch and thud, thud on an increasingly dry and dusty forest floor.  When we started seeing this happen, we knew the drought was on.

The curling leaves of a Rhodendron maximum shrub in TN.

When you start seeing the leaves curl up on these big Rhododendron bushes you know they are conserving their resources and stressing out a little.  We have research sites stretching from the piedmont of South Carolina to the mountains of North Georgia and Western North Carolina all the way over to the Cumberland Plateau of Tennessee.  We have been visiting these sites all summer and fall watching drought take hold and the subsequent fires start.  Here is a video from a site in TN.

video

I realize you may not be impressed by the quality of that video, but please notice 2 things.  1) The loud crunching of leaves as I walk.  2) The complete lack of water coming over that large cliff.  This is what is usually going on at Upper Piney Falls.





Photo of Piney Falls borrowed from American Travel Journal Blog.

Thankfully, none of our research sites are in danger of burning...yet.


And here is the problem.


We are in a drought y'all! These dry forest conditions are perfect for ignition of wildfires and boy are we having our share of wildfires. 

An aerial image of fires in the Southern Appalachians compliments of NASA's Aqua Satellite.

Remember that in our Southeastern forests there are beneficial, non-threatening fires.  You can learn about those here.   The wildfires we are experiencing now are not of that amiable variety.  So in these treacherous conditions please take Smokey's advice:









Tuesday, November 1, 2016

Hungry, Hungry Lari!

This is a very satisfying part of my job...



video

A young, healthy Laricobius nigrinus beetle digging into an Adelges tsugae ovisac.  I just finished releasing these predators out at some of our hemlock restoration plots.  What a great way to spend a day! 










PB010023

Wednesday, October 26, 2016

The Mystery of Dying Rhododendron

One of the most recognizable plants along the Blue Ridge Parkway is Rhododendron maximum, especially this time of year.  While the leaves of surrounding trees make there seasonal change from dull green to bright yellows, oranges and reds, Rhododendron sits underneath just as green as an evergreen should be.

  Healthy Rhododenron shrubs along a section of the Blue Ridge Parkway.

But something strange is afoot in Floyd County, Virginia.  We were just investigating large swaths of dead and dying Rhododendron along the Blue Ridge Parkway near Mabry Mill.  If you are enjoying a drive this time of year in Floyd County you may have spotted this phenomenon.

Dead and dying Rhododendron shrubs along the Blue Ridge Parkway.

Dead Rhododendron shrubs under forest canopy.
 
We were alerted to this mortality event by retired forest pathologist Dr. Ed Barnard who, in his fashion, assembled a small team of experts that included a pathologist from VA Tech, a forest historian, along with a county forester and us.  Ed and the crew all did their homework and we found that this event is not without precedent.  Dr. Richard Baird of Mississippi State University researched similar Rhododendron mortality in the Great Smoky Mountains National Park a few years back.  A forest pathologist from the U.S. Forest Service (Dr. Steve Oak) also investigated this issue several years ago.  Rhodo samples have ended up in diagnostic labs from landowners with shrubs from their yards, but in all this no single culprit has been found.

Cross-section of healthy Rhododendron stem.

Here is a quick rundown of what we found on our short field visit.  Above is a stem from a healthy Rhodo shrub lacking any evidence of decay, disease, infection, or impairment.  Below are stems from shrubs showing various symptoms of decline, decay, and death.

 Cross-section from unhealthy Rhododendron stem.

 Cross-section from unhealthy Rhododendron stem.

Cross-section from unhealthy Rhododendron stem.

Can you see the difference?  This staining indicates that something just ain't right.

A section of Rhododendron root with staining.

We have successfully eliminated the possibility of  an abiotic cause such as windthrow, voles, or moles.  There doesn't seem to be an insect chomping away at leaves, stems, or roots. What seems most likely is that a root rot is hard at work in these areas. 

But, there are still other organisms that could be to blame.  Nematodes (microscopic soil worms) have been reported at high numbers in some of the affected areas.  Could the Rhodo simply be aging out?  Are environmental stresses to blame?  The area in question has experienced periods of flooding then drought in rapid succession over the past couple years.

The bad news, there is an awful lot of dead Rhododendron and we don't know exactly why.  There is some good news though.  This "decline" is only affecting R. maximum and not other important relatives such as Catawba Rhododendron, Mountain Laurel, and Blueberry.  The mortality is fairly limited in its range and doesn't seem to be spreading. 

A root/stem sample with fungal growth.  (Photo:S. Fraedrich)

We bagged up some samples form the field and sent them along to several pathologists to pore over.  Our hope is  to start unraveling this mystery and figure out an answer in case a similar "decline" event happens somewhere else.


Monday, October 3, 2016

Fire in The South Explained

I am excited about this!  Our SRS Center for Disturbance Science recently partnered with Untamed Science to produce a video that helps explain the complexities of forest fires in the Southern U.S. 


Enjoy!





Thursday, September 29, 2016

Hi-tech redneck...

Even Foresters use technology from time to time.  This week I have been playing with various sensors and data loggers that we will utilize in our hemlock restoration study.  Assembling, disassembling, wiring, and un-wiring to figure out what works and what will not.

Weatherproof data loggers (foreground) and pendant-style light sensors (background).

After some discussion and a small scale field trial out at our Bent Creek Experimental Forest  lab we decided to go with sensors that record light intensity, temperature, relative humidity, and soil moisture.


 A data logger and sensors deployed under tree canopy in 2 of our sub plots at Dupont SF.

We are interested in teasing out just what our hemlock saplings are experiencing from season to season.  This study is concerned with getting hemlock back on the landscape after we get a handle on that pesky hemlock woolly adelgid.  What matters more to our trees?  The amount of light they are exposed to?  The competing vegetation surrounding them?  The lack (or presence) of browsing mammals?  Conditions in the soil? And so on...

A re-purposed planting pot serves as a hat to protect our precious data logger.


Our truck parked on a forest road with one of our "cut" plots in the background.

 What a great place to work and a fantastic time of year!  Which reminds me, get all your fall color updates here for optimal leaf-looking.

Wednesday, August 31, 2016

In the thick of it...

We have been on our hands and knees sampling vegetation in our hemlock restoration plots for the past 2 weeks.

Andy checking out the ground layer vegetation in one of our control plots.

It is amazing what you can see when you stop and look for a while.  Our treatment plots are only approximately 10 square meters in size, but contain an array of eye-catching organisms.

 Likely an eastern tiger swallowtail caterpillar. 

Medeola virginiana, also called Indian cucumber root.

Two saddleback caterpillars, Acharia stimulea (I think).

The always distinctive Praying mantis.

 This parasitic wasp is Pelecinus polyturator.

What appears to be vertebrae and ribs from a snake kill.


Wednesday, August 24, 2016

Adelgid in the news...

Hemlock woolly adelgid is fit to print!

Mountain Xpress, a local publication out of Asheville, recently did a story on the adelgid and featured a cooperator of ours from the Hemlock Restoration Initiative.



Read the article article here and you will also hear what our very own Dr. Albert "Bud" Mayfield III had to add to the conversation.