Tuesday, July 25, 2017

Fire Effects: Party Rock Fire Aftermath, Part 3

Almost eight months have passed (as I write this) since the Party Rock Fire.  As time has passed, we saw the mountain turn green again as spring came.  Now summer is here and fire scars are apparent around outcroppings and along ridges where flames ran high and hot, driven by upslope breezes.  As the fire burned, many worried that the beauty of Rumbling Bald and connecting mountaintops would be permanently devastated and that the impacts to the community would be long-lasting, but those concerns were quickly allayed as we saw the wildflowers bloom in the spring and the tourists returned en masse, many interested in seeing the aftermath of the most devastating natural disaster to hit Hickory Nut Gorge since the 1916 Flood.

Since the fire, I have taken it upon myself to photo document as many post-fire effects as possible, in order to learn as much as I can about fire behavior and forest response in an area that has been largely un-impacted by catastrophic fire over the last century.  That’s not to say that we haven’t had fire in the Gorge before, but in terms of any sort of regularity, fire has been largely suppressed in the overall landscape of Hickory Nut Gorge.  This is partly due to the fact that the topography and forest makeup of the Gorge does not often lend itself to frequent fires and prescribed fires are very difficult to control in an area that has so many steep cliffs, outcroppings, and ravines.  Additionally, as the land has become more and more developed, the opportunities for conducting prescribed burns have decreased.  This does not mean that our forests won’t burn, as we well know they will, but conditions have to be just right to get the right kind of fire to be effective and landowners have to be open to fire in their backyard.

As I visit different areas where fire burned, I see varying effects.  The brown areas on the mountain that you see from down in the valley are dead, burned trees.  Underneath those brown patches, you can start to see green as regeneration is occurring, with seemingly dead trees producing sucker sprouts from root crowns (a process known as coppicing) and numerous herbaceous species starting to appear.  The effect is similar to what you would see after a forest has been clearcut, where new growth in the form of multiple stems come up from the cut stumps.  The only difference here is that the tree skeletons remain until they fall or are cut down.  Some of the most successful species that I am seeing right now in terms of regeneration are sassafras (Sassafras albidum), sourwood (Oxydendrum arboreum), sweetshrub (Calycanthus floridus), and black gum (Nyssa sylvatica)
Sassafras sprouts.
Sourwood sprouts around a charred tree.

Regeneration around a dead black gum.
One of the most incredible fire responses that I have seen across the majority of forest types is the coverage of ferns.  Typically ferns don’t dominate the forest floor, but post-fire the fern diversity appears to have increased and species' size and densities have increased, covering the forest floor  where other species would typically dominate.  This appears to hold true with other herbaceous species as well, given that I've seen spiderworts (Tradescantia sp.) and fire pink (Silene virginica) with larger than normal blooms and taller than normal heights.   Light gaps created where trees are dying or have already succumbed to their wounds are creating clearings where grasses and other forbs can establish, increasing biodiveristy until trees have a chance to re-colonize and close the canopy again.
Bracken fern (Pteridium aquilinum) covers the forest floor in dry forest near ridgetops.
Another interesting response is the changes in the shrub layer.  The fire had a huge impact on mountain laurel and rhododendron.  Mountain laurel has largely responded by starting to regenerate from their root crowns, but the large rhododendrons did not fair so well and are mostly dead.  This is because many of these individuals have lived way longer than was naturally intended, and the species as a whole has increased its presence in the natural communities it inhabits .  Rhododendron has come to dominate some of these natural communities, growing large and creating vast amounts of shade, but as a result of their overwhelming presence, they have reduced diversity because there has been no significant fire to keep them in check and maintain a normal growth form. 

On my last few excursions up the mountain, I have been very interested in what's going on at Party Rock; the place where it all started.  The reason for this is because it was the point of origin, but also because of its successional nature as a plant community.  Party Rock, before the fire, was an area covered with vegetated mats that were inhabited by mostly spikemoss and a few grasses, with occasional other species scattered around in the deeper mats.  On the upper slope of Party Rock, Virginia pine saplings grew in the thin soil.  During the fire almost every sprig of vegetation was consumed, leaving a blackened moonscape.  The only trees remaining were a few red cedars that somehow managed to escape the main part of the fire.  Today, if you visit Party Rock, it no longer looks like a moonscape.  Almost all of the soil mats have new vegetation.  Much of the spikemoss is gone, most of it completely consumed in flames, but it has been replaced by numerous grasses and other herbaceous species that before only maintained small populations.  Now Party Rock is green and lush.  A normally dry place, recent rains and the increased plant diversity have made some areas of Party Rock almost boggy, which is something that I’ve never seen up there.  Party Rock is normally a very dry environment.  While what we’re observing up there is mostly not unexpected, it’s so cool to see these expected responses play out, but on a scale that could not have been anticipated.
Twisted-hair spikemoss (Selaginella tortipila) is beginning to come back to Party Rock.

Roundleaf fameflower (Talinum teretifolium) is an interesting succulent that occurs at Party Rock.
Much of the blackened soil is disappearing as new vegetation slowly fills in the gaps.
Numerous forbs are slowly filling in the gaps on the exposed soil mats.
What was the occasional species occurrence now dominates with the loss of the spikemoss.
A sea of green.
More green.
Sumac (Rhus sp.) is a shrub that responds particularly well to fire and is quite beneficial to many different bird species.
Curtiss' milkwort (Polygala curtissii) went from a minor species to a dominant species at Party Rock.
Certain images make it appear as though no fire ever occurred here.
Grasses such as broomsedge (Andropogon virginicus) are re-appearing in this succesional habitat.
More regenerating spikemoss where it had previously burned up.
Another area that I thought was really intriguing was a small glade on the east side of the mountain just above a rock face.  Glades are transitional areas that are often found between granite domes and woodlands and are usually dominated by grasses.  Glades also are often home to the occasional shrub such as indigobush (Amorpha sp.) and rare species such as yellow honeysuckle (Lonicera flava) which I found at this particular site.  Transitional zones are prime habitat for lots of different species, so seeing the response of these forest glades post-fire will perhaps be an indicator of what we will see in other transitional zones.  There's a really nice glade on the east side of Cedar Knob that I would love to visit.  The fire burned really hot there, so it would be really interesting to see how that area is responding. 
Grasses are the dominant species in this glade near an east-facing granite dome on Rumbling Bald.
This is not to say that there aren’t negative impacts.  Already we are seeing invasions of non-native invasive species such as princesstree, tree-of-heaven, and oriental bittersweet.  Again, this was an expected consequence, but it is one of those discouraging realities that land managers will have to grapple with for years to come.  A prediction I made shortly after the fire was that there would likely be new scattered populations of oriental bittersweet in places we haven't seen it before, and unfortunately that prediction seems to be coming true.  Birds are the primary dispersal mechanism for bittersweet seeds, and they have been depositing these seeds in the soils of Hickory Nut Gorge for several years now in Hickory Nut Gorge as bittersweet expands its western North Carolina infestation from its point of introduction in the Asheville area.  Bittersweet has been present in Hickory Nut Gorge for many years now, but our thick forest canopies have mostly helped restrict its growth.  Bittersweet loves disturbed areas, particularly light gaps and will often lie in wait for the perfect opportunity to germinate.  Fire provided the needed light gaps and removed the litter layer in many places, providing the necessary ingredients for successful germination.   In a sunny environment, bittersweet wreaks havoc on native species by climbing into the canopies of trees, much like kudzu.  However, bittersweet is really worse than kudzu due to its high seed viability, ability to easily form monocultures, and general vitality.  Unlike kudzu which can be quite manageable with the right resources, bittersweet is much more difficult to control once it gets well established.  This species and others will present some difficult challenges in the years ahead.
Princesstree seedlings are already establishing in many burned places and pose the biggest near-term management challenge
 There are a lot of dead trees out there and more will die.  Already many trees are experiencing fungal growth on their trunks and around their root crowns.  Many of these trees have leaves on them, but their canopies are sparse, so death is right around the corner.  In the short-term, as mortality occurs it will increase the amount of available fuel for future fires, create more light gaps for invasive species establishment, and allow for re-colonization of some less desirable, fire-intolerant species such as red maple and yellow poplar.  While maples and poplars certainly have their place in eastern forests, there role as secondary associate species has been elevated due to changes in soil moisture and lack of regeneration in dominant species, primarily oaks.  This is being widely attributed to fire suppression, poor forest management practices, and global climate change, particularly in montane oak-hickory and pine-oak-heath forest types.
Many trees in this spot are dead or dying, providing much needed light to a clean forest floor.
This is a transition zone between high and medium intensity fire where tree mortality is a little lower.
Fungal growth on the outer bark of trees is a sure sign of mortality.
A beautiful clearing where the forest transitions from an open light gap back to closed understory.
For land managers it will be imperative to try to conduct periodic prescribed fires in the future where possible.  In many cases this will simply not be feasible, but that does not lessen the importance or the need.  For communities and citizens of the Gorge, being firewise and understanding the role of fire in the environment will go a long way towards improving the health of our forests, as we seek to manage fire hazards and control invasive species on private property, particularly in the area we refer to as the urban/wildland interface.  The important thing is that we never forget that the risk of fire is ever present and that it is a natural dynamic in the landscape.  Understanding that concept is key to making wise decisions that protect property, lives, and keep our forests healthy.  

To see more post-fire pictures from Party Rock and other areas of Rumbling Bald, check out my photo album on Flickr by clicking on the link:

Until Next Time!

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