Sunday, August 21, 2016

Longleaf pine restoration - bring on the fire, but first....

Elsewhere on this blog I have discussed the importance of fire for the maintenance and recovery of longleaf pine (Pinus palustris) habitats. I have not discussed the numerous challenges in being able to do so, and they can be considerable. This page will not be a full accounting of these challenges but is predicated on some of these. Namely, long-unburned stands may have extraordinary fuel loads that can be explosive and dangerous to reintroduce fire into.

Longleaf pine stand and prescribed burn near the coast of North Carolina;
flame lengths and intensity are greater than many managers would prefer 

   Longleaf "flattop"; these trees often represent remnants of
earlier forests skipped over by loggers
                                                            Bringing fire back into long-unburned stands places serious stress on the very trees fire management is intended to support. In stands where longleaf pines are sparse (image above) or where the individuals include older relicts, each tree is precious and valuable (image left). Longleaf remnants with "cat faces" (signs of previous naval stores harvest) are especially susceptible to fire damage (image below).                                                                 
Mechanically reducing the fuels in such stands can help protect high-value individual trees and lower overall fire intensity. However, doing so across large and heavily overgrown stands takes a concerted approach. Several years ago, we stepped up and took one (a concerted approach, that is).

The "concerted approach"!
Skid steer equipped with forestry cutter
We acquired a skid steer equipped with tracks to minimize ground disturbance, a special cab to protect the operator, and a "forestry cutter".  Examples of how we used it are shown below:       
  Disappearing mower and mowed swath
 through heavy "bay" fuels
Brunswick Co, NC

Mower headed straight toward remnant longleaf pine, barely evident from
a distance due to tall shrub and Pond Pine (Pinus serotina) encroachment

In these circumstances it was the perfect way to go "looking for longleaf".  

The images below show this stand before and after treatment. Note the lone Longleaf pine with the Y-shaped canopy near the center. Amazingly, a young longleaf pine was hiding in the dense brush immediately in front of this tree (click & enlarge image right). After clearing, the stand displayed the open structure typically associated with longleaf pine savannas and woodlands - a restoration success?.  Comment appreciated! 

Longleaf pine stand with relicts, after mulching treatment (same stand as above)
Note - turpentine faces on 2 of the trees.
Brunswick Co, N.C.

Tuesday, August 16, 2016

Shenandoah sinkhole ponds

Virginia Sneezeweed (Helenium virginicum) is a federally-listed "threatened" species associated with Shenandoah Valley sinkhole ponds in Virginia. A number of years ago, the species was also confirmed in Missouri in similar habitat, creating "one of the great phytogeographic mysteries of the Eastern North American flora" (1).

Virginia Sneezeweed (Helenium virginicum)

Large patch of Virginia Sneezeweed along margin of sinkhole pond, Augusta County, VA


This is a seed-banking species whose populations fluctuate widely at a given site. Flowering stems can become prolific and abundant under the right conditions (2) (image left)

Water levels in the sinks vary widely and fluctuate seasonally. The example shown below held over 12" of water while immediately adjacent ponds were completely dry.  Not surprisingly, the vegetation may also be quite variable both seasonally and between sites. For more detailed descriptions see (3) & (4) below.

Shenandoah sinkhole pond with standing water (July 12, 2016)
Note: Pin Oak (Quercus palustris) overhanging branch  

Shenandoah sinkhole pond, same site as above (August 04, 2016)
standing water still present, emergent Persicaria and Polygonum spp. superficially dominant
Shenandoah sinkhole pond with Buttonbush (Cephalanthus occidentalis) and emergent Eriocaulon

The sinkhole ponds are biologically important features of the Shenandoah Valley region and they support many other species in addition to Virginia Sneezeweed. These ponds are also extremely important for dragonflies (5) and reptiles and amphibians (4), in part, because the ephemeral water levels often restrict predatory fish populations.
Spotted Turtle (Clemmys guttata) - the only populations west
of the Blue Ridge are found in sinkhole ponds (4)
Image from coastal plain of VA
Amphibian egg masses in sinkhole pond (03-23-16)

Dragonfly exuvia on Lowland Loosestrife (Lysimachia hybrida)
in sinkhole pond, Augusta Co

Lowland Loosestrife (left) is considered significantly rare in Virginia, and known from a handful of sinkhole ponds.

A number of other rare plants may also be found:

Boltonia montana  - Augusta Co., VA (08-4-16)

Valley doll's daisy (Boltonia montana) is an extreme global rarity, known from 4 VA sites, all within a few miles of one another in Augusta County's sinkhole ponds. Described as new to science in 2006, this species also has an unusual phytogeographic pattern.

Northern St. John's Wort (Hypericum boreale)  -- Significantly rare in Virginia; known from Shendandoah sinkhole ponds and disjunct to interdunal ponds near the coast.

The ponds themselves are globally-rare and imperiled, In the two examples shown below, one has been artificially deepened and stocked with fish and the other used as a mini-landfill.

It's hard to image more important and special habitats. I hope to be able to play a small part in protecting them.

(1) Virginia Plant Atlas:
(2) Draft Recovery Plan:
(3) Descriptive Ecology:
(4) See Montane Depression Wetland types and links here (
(5) A new species of Boltonia....SIDA 22:873-886.