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.

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:

Hungry, Hungry Lari!

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

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! 

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.

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!

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.

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.

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.

Additional traps have just gone up...

I was back in Tennessee this week installing additional traps for walnut twig beetle.  Our funnel traps haven't yielded any beetles thus far this summer, so we are baiting fresh walnut bolts with lures in hopes of enticing the critters.  Along with lures, we attached sticky cards on each bolt so we can get an idea of just what insects we are attracting.

A black walnut bolt loaded up with walnut twig beetle lures and a sticky card.

 

We are throwing everything we can in suspect trees, hoping to pick up on some walnut twig beetle activity.  Last summer, we observed a real spike in beetle activity during the month of August.  We are hoping to see the same this year, if not, then we will be re-thinking our planned experiments for September and October.

One of the black walnut plantations we are working in outside of Knoxville, TN.

What's cooking this month?

Black walnut branch sections will be dipped in wax to seal in moisture.

Our lab inventory often reads like a list for a camping trip... saw, stove, propane, pot, spoon, etc.  But recently what we have been cooking in the field are small vats of paraffin wax.  We are preparing for another experiment involving the, now elusive, walnut twig beetle.  After several experiments, we have figured out that the beetles find it hard to resist a fresh, baited black walnut "bolt".  These 1-foot long branch sections, which we refer to as "bolts", come from a hazard tree that was just removed from our Bent Creek property.  Waxing the ends of these bolts assures us the most fresh sample possible. 

 Cooperators at a field site in TN hoisting a funnel trap in to a tree canopy.

Early in the month of June I was at a federal property in Tennessee setting up Lindgren funnel traps.  Yep, that small black and white thing making its way into the tree-top.  Bud and I (along with another cooperator) also deployed several sets of large, fresh bolts (3-ft sections) into about a dozen trees in and around Knoxville.  The beetles have been hard to find this year, which is good news for black walnut trees and landowners who have been affected by recent infestations, but makes running field experiments difficult.  We are hoping to pick up some activity soon for experiments we would like to initiate in September.

We will keep you posted.

 

Bug Day at the Kent House

Great work Stacy and JoAnne! 
This is a huge annual event hosted by the USFS folks in Pineville, Louisiana.

Silver flies...

We were in Tennessee this week with cooperators from Vermont releasing these beauties onto heavily adelgid-infested eastern hemlock trees. 

A silver fly (Leucopis spp.) adult as seen under the microscope.

A heavily infested hemlock branch with 2 generations of adelgid.

Silver flies are native to the Western U.S. and are a predator of hemlock adelgids in those forests.  I was fortunate to be part of the team that released the very first silver flies in the eastern U.S. at this very same site last year.  We had promising results from that experiment and are hoping for more of the same this year.  

Counting adelgid along stem sections on hemlock branches.

Hemlock branches are labeled and adelgids are counted.

Releasing silver fly adults into a sleeve cage.

I will return in about one month to collect our first set of branches and we will see if the flies were able to feed and successfully reproduce.  Our cooperators from Vermont will set up another set of replicates in New York later this month.  We are working the western and northern edges of the hemlock woolly adelgid infestation. 

A spring in our step...

One of the many field experiments we currently have running deals with restoring hemlock trees to the landscape.  When we finally do solve the hemlock woolly adelgid puzzle, land managers of all sorts and sizes will want to restore their hemlock forests.

A bucket of fertilizer rests against one of our planted hemlock trees.

 Just this week I was fertilizing planted hemlocks at field sites in a an experiment designed to answer some questions regarding how best to get healthy hemlocks back in the forest.  Trees were planted at the tail end of 2013.  Some were treated with insecticides protecting them from the adelgid and some were not.  Some were fertilized, others were not.  A combination of all treatments was used on some seedlings, then others had nothing done to them.  We are taking annual measurements in an effort to find out what treatments grow the healthiest trees.

 A birds nest propped in the young, but sturdy branches of a hemlock seedling.

I was pleasantly reminded that species other than adelgids use our hemlock trees.  

 Eastern tent caterpillar crawling on a hemlock branch.

Please meet Malacosoma americanum, the eastern tent caterpillar.  You have probably noticed the silk tents that these critters construct on many of the broad-leaved trees this time of year. 

For The Future

Planting trees early in spring,

we make a place for birds to sing

in time to come. How do we know?

They are singing here now.

There is no other guarantee

that singing will ever be

-Wendell Berry

 

Predator Beetle Impact Assessment

We recently returned from field sites where the hemlock woolly adelgid predator Laricobius nigrinus was released several years ago.  We are contributing to a region-wide study of the impact this particular predator beetles is having on adelgid populations.

A heavily predated section of branch.

We were elated to find hemlock branches where predators have ransacked HWA ovisacs.  We retrieved our final branch samples this past week and they are now in our lab space at UNC-Asheville. 

Branch samples from our NC site ready for the growth chamber.

The branches are set in floral foam and placed in cups so they will stay as fresh as we can keep them for as long as possible.  The growth chamber is set to mimic night and day light conditions and temperatures so the beetles and adelgids will continue developing.  Every few days, we will be checking each branch for Laricobius larvae that are dropping off after feeding.

Branch samples from NC in the growth chamber.

Working in the Mark Trail Wilderness

On a recent visit to an ongoing field experiment in the mountains of Georgia, my colleague mentioned that we had just passed into the Mark Trail Wilderness. 

A fact that, I freely admit, has escaped me all this time.  In my defense, we are usually focused on things like how to install our experiment 30 feet up in the canopy of a hemlock tree. But I digress.

My colleague went on to describe a brief report she had heard in the news about the recent death of an artist who illustrated comic book character Mark Trail.  I was completely ignorant of the significance of Mark Trail and the existence of his comic, but the few details she related piqued my curiosity.   

Ed Dodd started writing the comic strip "Mark Trail" in 1946.  Jack Elrod started working with Dodd in 1950 before taking over the comic in 1978.  Our hero, Mark, is a ruggedly handsome outdoorsman whose pursuit of the simple pleasures in life are often interrupted by poachers, thugs, and goons invading those peaceful settings and selfishly destroying beautiful natural areas.  Mark's career as a photojournalist and love for wilderness propel him into the fray as a hero fighting "to preserve the integrity of the American wilderness for future generations."

But it's not all confrontation and right-hooks from our sophisticated man-of-the-woods.  Mark is an intelligent instructor and advocate for your safety.

In the age of information overload, I somehow missed this gem of a comic. Lovingly illustrated, these comics are chock full of factoids about our natural world and our role in it.  I am on a mission to find out more.

Both Dodd and Elrod were natives of Georgia and outdoorsmen themselves.  These men and their comic strip showed millions that being an environmentalist is not only important, but cool.  Over the years, the comic and authors received many accolades and honors.  Not only is there a designated wilderness area named for this trendsetter, but Mark Trail is the official spokescharacter for NOAA.

Mr. Dodd passed away at the age of 88 in 1991 and Mr. Elrod passed away just this past February at the age of 91.  Thankfully, their legacy lives on through Mr. James Allen, yet another Georgian, now responsible for navigating Mark Trail in this new era of invasive species and fragmented landscapes.  

Thank you gentlemen for a creative and educational romp through our woods!

P.S. And check out this special one celebrating the 50th anniversary of the Wilderness act.