Engineering an Air Conditioner

Model of an air conditioner.

Another view of model.

My last post on Ice Mountain was about a place where an unusual geologic formation had created natural air conditioning on a hillside in West Virginia. In this week's post I wanted to show this really nifty model created by one of the young mechanical engineers I work at JMT, my new employer. Wafic Omran built this nifty contraption out of plastic trays and copper tubing for a career day at an elementary school in northern Virginia, to show kids how an air conditioner works. Many adults don't have an idea of the principles involved either, we just know that we'd be miserable without it during the summer, as mankind was for all the centuries before its invention.

Cool water is pumped from the lower tray up to the upper tray by an aquarium pump. As the water flows down through the copper pipes, a small fan aimed at the copper tubes cools the air as it passes between the pipes and as a result, the air temperature drops on the other side. A thermometer clipped to the plastic jar shows that the air has been cooled about 2 degrees with this simple apparatus. I couldn't resist showing this really cool demonstration of how an air conditioner works!

Ice Mountain

Twin flower (Linnaea borealis) and partridgeberry (Mitchella repens).

A few Sundays ago I visited a most unusual site with the Piedmont Chapter of the Virginia Native Plant Society (VNPS). Ice Mountain Preserve in West Virginia, now owned by the Nature Conservancy, is one of the weirdest places around--a naturally-occurring refrigerator! At the bottom of an algific (cold-producing) talus slope, air is drawn in thru vents, and insulated by a layer of very thick sandstone blocks underneath, the air is cooled, causing ice to form inside small cavities on the side of the hill. The cold air flowing from these vents creates a micro-climate on one side of the trail, where plants normally found in sub-artic regions such as northern Canada can flourish. This site has been designated as a natural heritage site; access is restricted and arrangements must be made to visit with a guide.

Our group met at the Old Inn in North River Mills, a small town that used to number a few hundred back in the 19th Century and gradually depopulated until only one inhabitant remains at present. Our guide and docent, Kristin, told us that back in the 19th Century the local inhabitants used to gather the blocks of ice during summer to cool drinks and make ice cream. Unfortunately this practice depleted much of the ice in the crevices, but some ice can still be found.

Ice inside a cavity at Ice Mountain

Storm clouds had been gathering as I drove to the site. As we were starting out on the trail, a peal of thunder warned of the storm's approach, and our group decided to return to the inn and wait until it had passed. A wise decision, as we would have been completely soaked had we continued. Kristin entertained us with stories of the inn, and we explored the interior while waiting for the skies to clear.

Eventually, the rain stopped and we started out again. The path led up a hill, and through woods carpeted with understory plants such as bedstraw, black cohosh, southern beech fern and maidenhair fern, some of which I recognized from previous encounters, but many plants here were new to me, such as this Appalachian wood fern.

Appalachian wood fern (Gymnocarpium appalachianum)

The Cacapon River

As we descended the other side of the hill and rounded a bend, the path began to parallel the Cacapon River. We were asked to walk single file on the trail, in order to protect the fragile vegetation. Wending our way through a forest of huge Rosebay rhododendrum (Rhododendrum maximum) which would probably not bloom until July, the temperature became perceptibly cooler as we reached the talus slope.

Hiking through a forest of rhododendron.

Ice Mountain mist

Mist wafted from the cavities along the base of the talus slope. One of the group had brought a thermometer which we placed inside one of the small cavities. It was about 80 degrees ambient that day, but inside the cavity the thermometer read 38 degrees. Ice could be seen inside one of the larger cavities.

Ice Mountain crevices

The rare plants began to appear on the side of the trail with the crevices: Bunchberry (Cornus canadensis), Canada Mayflower (Maianthemum canadense), Minnie-bush (Menziesia pilosa), Nannyberry (Viburnum lentago), Late low blueberry (Vaccinium pallidum), and many more that I missed, being too far behind our docent. The range of botanical oddities was impressive.
 

Bunchberry (Cornus canadensis)

Canada mayflower (Maianthemum canadense)

Late low blueberry (Vaccinium pallidum).

We came across the lovely twin flower (Linnaea borealis) growing in amazing profusion over just one section of the trail. This low creeper grew intertwined with Partridgeberry, Canada Mayflower, Bunchberry and mosses along the ground. A lone specimen of the Prickly rose (Rosa acicularis) was so precarious it had been protected from browsing animals behind a small fenced enclosure.

Twinflower grows profusely over the rocks.

Prickly rose (Rosa acicularis) behind fence.

Our docent Kristin told us that genetic studies of the boreal plants at this site revealed that this group of plants were likely the remnants of vegetation left from the last Ice Age that retreated about 10,000 years ago. Unlike we humans, who can only inherit one set of chromosomes from each parent (haploid), plants, particularly ferns and other flowering plants are capable of inheriting more than one set of chromosomes from each parent to become polyploid. This process happens as plants reproduce over a number of generations, whereas early generations tend to have only two sets of chromosomes, which the plants here were found to have.

Beyond the patch of Twinflower we came across a flowering clump of Northern bedstraw (Gallium boreale), Skunk currant (Ribes glandulosum) and Horsetail clubmosses (Equisetum arvense). The afternoon was waning, so reluctantly, our group started the trek back to the inn. I would have liked to climb up to the top of the hill to observe the ravens nesting there (I had seen them while driving in) but by then my feet had given out. It was time to head home.

Northern bedstraw (Gallium boreale)

Horsetail clubmoss (Equisetum arvense) and witch hazel seedlings.

Skunk currant (Ribes Glandulosum)

I hope to eventually find time to paint the tiny and exquisite Twinflower, so unique and beautiful!

Galearis Field Sketch

Galearis spectabilis orchid, colored pencil sketch, 10" X 8".

This is a small sketch I did about a month ago as a color study of the Galearis spectabilis orchid when it was about to bloom at Thompson Wildlife Management Area. The flower buds had not opened yet, and the leaves still had the classic vase-shape of a young plant. As the plant matures, the leaves will flatten out and spread wider.

My 60-color set of Faber-Castell 'Polychromos' pencils does not have enough color range to render the actual colors of the plant. The leaves are not that yellow-green, and the flower buds are a paler mauve, but it was still a fun opportunity to study the contours of the leaves using line-work, and enjoy the lovely spring day outdoors.

Lake Waccamaw

Lake Waccamaw State Park rangers guide the NCNPS group.

The following morning the North Carolina Native Plant Society (NCNPS) group met at Lake Waccamaw State Park for a tour of the trails surrounding the Visitor's Center. Covering 36 acres, Lake Waccamaw is the largest of North Carolina's "bay lakes," a term for this type of oval-shaped fresh water lakes. On Friday evening, the Head ranger had given the group a talk describing some of the theories about the formation of these unusual lakes that occur in certain regions along the eastern seaboard. I remembered reading one theory in a National Geographic article years ago about a prehistoric meteor strike leaving these craters which later filled with water and developed certain type of ecosystems, but evidently this theory has now been dismissed as unlikely. The most plausible theory seems to be that the lakes formed as a result of a combination of the massive land and ocean processes that took place during the Pleistocene era, when this area was submerged. The lakes in this area all seem to have a high limestone shelf on their northwestern rims and sandy shores on the southeastern portions, and three varieties of bay trees predominate: sweet bay, red bay and loblolly bay.

Loblolly bay (Gordonia lasianthus), the leaves have crenulate edges.

As we began our walk, the Rangers explained that the park had recently begun to use managed burns to control the undergrowth and try to restore native habitats. The fire doesn't damage the established trees, and improves the overall health of the forest, but the rangers were of the opinion that a successful controlled burn is very much an art, and the precise weather conditions need to be taken into account if the fire is not to get out of control.

Prickly pear (Opuntia humifusia) growing among bracken ferns.

Pink spiderwort (Trandescantia virginiana)

I was surprised to see Prickly Pear blooming among the bracken ferns near the Visitor's Center, and was assured that these cacti are actually native to the entire east coast from Florida to Connecticut--I had always thought they had been introduced from the southwest and naturalized. We also came across a lovely pink-flowered Spiderwort --I've only seen the blue Spiderwort (Trandescantia virginiana) before.

Fetterbush (Lyonia lucida) growing under turkey oaks.

Honeybells (Zenobia pulverulenta) with Fetterbush  in back.

The forest floor was carpeted with bracken and other ferns. Flowering native bushes such as Fetterbush (Lyonia lucida) with small pinkish bells and the sweetly scented Honeybells (Zenobia pulverulenta) bloomed below the shelter of the turkey oaks. I spotted a tiny-leaved plant on the forest floor and was told this was Pixie Moss (Pyxidanthera barbulata)--it could make a lovely ground cover in the right garden.

Pixie Moss (Pyxidanthera barbulata)

All these were a completely new community of plants to me, a fascinating environment to be introduced to. There were also many birds here: a number of warblers, mocking birds, and brown thrashers were spotted by the bird-savvy among the group.

The time for our departure came much too soon--Linda and I needed to start our 7-hour trip back by noon in order to get home at a decent hour, so we said goodbye to our new-found friends in NC around eleven and started walking back to our car. One lone wild turkey crossed our path, and Linda lingered to identify an indigo bunting along the way.

I wished we could have stayed one more day--despite our precautions, we still encountered a huge backup on I-95 after we passed Richmond this Sunday evening, and spent almost an hour fighting the traffic to reach our exit. The sun was just setting on this beautiful spring day as we returned to the Shenandoah Valley.

The forest at Lake Waccamaw.

For more photos of our walk at Lake Waccamaw State Park and the Green Swamp see my Flickr album here.

Deep in the Ditches of North Carolina

Cleistes bifaria

Last weekend my friend Linda and I traveled to North Carolina to join the North Carolina Native Plant Society (NCNPS) on their annual Green Swamp excursion. Since this has been a very late spring and all plants are about 2-3 weeks later than usual, I had expected that we would not see some of the blooms I'd hoped for. In fact, we did not see the famous Rosebud orchid (Cleistes divaricata), but we did find some blooms of its smaller cousin Cleistes bifaria (above), an equally lovely sight.

We arrived too late on Friday evening for the roadside botanizing in the vicinity of Whiteville, NC, so on Saturday morning our guides took those of us who had missed that on to the roadside sites first. A huge storm system in the area (covering Virginia as well) had dumped over three inches of rain two days before, and as we left my house in Front Royal, the first two holes on the golf course at the entrance were under water.

As we learned, these areas of NC are usually wet anyway--we had to wade ankle-deep into a roadside ditch to reach our first site. Linda and I had brought only old shoes, so despite our best efforts to avoid sinking, there was no help for it. Once over the initial chill of the water, it was just fine. Later on in the day, in the heat of the afternoon, our soggy shoes felt even better.

Sundew (Drosera intermedia)

Our first sightings were sundews, small insectivorous plants: Drosera capillaris (very tiny), Drosera intermedia (above) and Drosera filiformis, a slightly taller variety, growing in the muck among spagnum moss. Pitcher plants (Sarracenia sp.) were plentiful, and we encountered several varieties in flower: S. rubra, S. flava, and S. minor. Our guide, David McAdoo, pointed out something fascinating--the spots along the top and back of the hooded pitchers are actually transparent "windows" that allow sunlight to reach the inner surface of the pitcher plant for photosynthesis.

Hooded pitcher plant (Sarracenia minor).

Blooms of Sarracenia minor.

Sarracenia flava.

There were Venus Flytraps here and there, the small plants were hard to see among the grasses. And other lovely spring flowers too, purple Skullcap and a very pretty orange clover-like one whose name I didn't note down, bracken and cinnamon ferns. Also Butterworts (Pinguicula), club mosses and  plants so numerous I couldn't write them all down.

Skullcap (Scutellaria intergrifolia?)

I didn't get a single photo of the lovely Lady's tresses orchid (Spiranthes praecox) in focus--there was also a flower spike very similar to Lady's tresses from a distance, white colic root (Alestris farinosa) which ironically, I did better with. One has to look closely-- in Spiranthes as its name implies, the tiny orchid flowers grow in a spiral form around the scape. 

Colic root (Aletris farinosa)

Rose Pogonia (Pogonia ophioglossoides)

Rose Pogonia orchid grew at this site in small clumps along the ditch. After about an hour and a half here, it was time to drive on to our second stop, the Billboards--a grassy elevation sandwiched between four billboards. Heading south on 130, there were so many other billboards it would have been hard to figure out which four were the right ones, if we hadn't been caravaning.

The Billboards.

Sarracenia rubra.

Venus flytrap (Dionaea muscipula)

Sarracenia purpurea.

Here were more pitcher plants in profusion, S. rubra, S. purpurea, and S. flava, Venus Flytraps (Dionaea muscipula) in bud and flower, Sweet Bay and Maleberry (Lyonia), which looks very like a blueberry. Farther down, finally, were a few of the orchids I'd come so far to see: Cleistes bifaria and one specimen of Calopogon pallidus (the pale Grass Pink). It was hard to photograph the flowers blowing in the breeze, but I managed to get a couple of decent shots.

Calopogon pallidus

Side view of Calopogon

From my orchid studies I've learned that most orchids are resupinate, which means the flowers are rotated on their stems to be updside down, so the lip (labellum) is at the bottom of the flower. This arrangement provides a landing pad for the pollinating insect. Calopogon orchids are the exception, as you can see from the photo, the labellum is positioned above the petals and sepals. Instead, the hairs on the labellum function as a lure for the insect, and when a bee tries to lands on them, its weight causes the hinged labellum to swing down and position the bee onto the column for pollination.

We left the Billboards around noon and headed south to Shallotte for a bathroom break at the local Popeyes. We ate our box lunches in the parking lot. After lunch it was finally time to visit the Green Swamp. The Green Swamp is actually not a swamp so much as a long-leaf pine savannah or "pocosin," the native American name for these local wetlands. They have acidic, peaty, poorly-drained soils that are oligotrophic, meaning nutrient-deficient, which is probably why so many of the plants found in this environment are carnivorous. The Green Swamp is noted for its amazing diversity of plants, over 50 different species have been counted in about a one square meter plot. We entered an area known as the Big Island Savannah by crossing another deep watery ditch.

Entering the Green Swamp

Our first sighting was a narrow-leaf Milkweed (Asclepsias longifolia), and more pitcher plants of S. flava and S. purpurea.

Narrow leaf Milkweed (Asclepsias longifolia)

After a while we drove on to another part of the Green Swamp where the scent of Swamp Azaleas (Rhododendrum viscosum) pervaded the air--thickets carpeted the shady parts of the savannah, and swallowtail butterflies flitted about. We came across one rather beat-up Grass Pink orchid (Calopogon barbatus?) but my single shot was not in focus .I hoped we'd come across a couple more specimens but that was the only one I saw.

Swamp Azalea (Rhododendrum viscosum)

After we left the Green Swamp we drove on to another site at Boiling Spring Lakes, where the most incredible display of Rose Pogonias I've ever seen stretched for what seemed like a mile along a ditch. According to our accompanying botanists, the Pogonia spreads by underground rhizomes, and here it had obviously enjoyed many years (hundreds?) of uninterrupted growth to cover such an expanse.

Rose Pogonias near Boiling Springs Lakes.

Rose Pogonias grow among Spagnum moss and ferns

Rose Pogonia (Pogonia ophioglossiodes)

By this time the second battery for my camera was running low, and I was trying to conserve power, so I limited the number of my shots--with an extra battery I could have gone on to take hundreds of photos here.

Our last site of the day was yet another roadside ditch where the Venus flytraps seemed to be unusually red in color--perhaps the lack or addition of a particular nutrient? There were several more Cleistes bifaria orchids in bloom here, but at this point, my camera battery finally gave out.  After covering so much ground in one day we were tired, so it was time to head back to Whiteville to clean up and rest before dinner at the Forestry Museum and the native plant auction.

Venus Flytrap (Dionaea muscipula)

Blooms of Venus Flytrap

North Carolina has the most fascinating roadside ditches I've ever seen! Next time I'm here, I'll bring pair of oystering boots or Wellingtons. Sunday morning at Lake Waccamaw will have to be a separate posting, as this is already way too long.

For more photos see my Flicker album here.

Trillium Trail 2014

VNPS members on the Trillium Trail

On the last Sunday in April I hiked the Trillium Trail at Thompson Wildlife Management Area (Thompson WMA) with the Piedmont Chapter of the Virginia Native Plant Society (VPNS). Spring is so late this year that the thousands of trilliums (Trillium grandiflora) this area is famous for were barely out of the ground; only a few blossoms here and there and a few patches in the sunnier part of the lower portion of the hill were visible. At this higher elevation the tree leaves had not begun to unfurl yet, and it was much chillier at the top of the ridge than in the valley below.

Our hike leader Sally said that at one time it was thought that the trillium flowers started out as pure white and turned pink with age, but this is actually not so. Seeing is believing, and here was the proof--many of the just-emerging blossoms were a soft pink in bud and recently-opened blossom. I've heard theories that the trilliums in this huge stand are the result of many years of natural hybridization of several species such as T. grandiflora with T. erectum, but botanically, the pink variety is classified as T. grandiflora forma roseum and wavy edges on the flower are one characteristic of this variant.

Pink Trillium bud (Trillium grandiflora forma roseum)

We took the side trail leading to the Appalachian Trail (AT) with Sally pointing out many interesting plants, some of which I was familiar with, and others unknown to me, including a native mustard that is the host plant for the West Virginia White butterfly (Pieris virginiensis). I didn't know that this native butterfly has been steadily declining since the 1990's, and one reason is that the butterfly seems to get confused and lays its eggs on that invasive plague, garlic mustard, instead of its host plant. The caterpillars cannot survive on garlic mustard, and when the butterfly does not reproduce, the population in those areas can be wiped out.

A lady who befriended me on the previous hike, Mary Keith, told me that the Piedmont Chapter  maintains the Trillium Trail to try to keep the garlic mustard under control, and sure enough, as we walked she and several other ladies pulled up any traces of the noxious invader we came across and bagged them to dispose of them later. Evidently garlic mustard is so programmed for survival that even after being pulled up, any flowers on the stems can set seed and spread, so the plants can't be left lying around on the ground.

Turning left onto the AT we encountered many early spring ephemerals blooming along trail: bloodroot, wild ginger, blue and smooth yellow violets, and Canada mayflower.

Bloodroot flower (Sanguinaria canadensis)

Wild ginger flower (Asarum canadense)

Canada mayflower (Maianthemum canadense)

Blue and Smooth Yellow Violets.

I looked for the Showy orchid, hoping to catch a glimpse of some and eventually I spotted one nice clump emerging by the side of the trail. The fleshy leaves formed a curious vase-like cup with the tiny flower spike bud barely visible inside.

Showy orchid (Galearis spectabilis) emerging from forest floor

Further down the hill we encountered a seep, full of skunk cabbage and other interesting plants, among them the false hellebore I had seen last year at Big Meadows on Skyline Drive, and another type of saxifrage with toothed leaf margins.

False Hellebore (Veratrum viride)

 At the junction of the AT with the fire road we turned left to go up the hill. Many huge trees had come down during the harsh winter, the dead trunks and branches strewn all over the ground, cut only to allow passage on the fire road. The lumber on the ground obscured most of the areas where I'd seen Yellow Lady Slipper orchids in years past, but I found a few orchid plants emerging from the leaf litter. At this stage, the plant would have been difficult to identify if I hadn't known the location

Yellow Lady Slipper orchid emerging from the forest floor.

As we were approaching the end of our circular hike, near the parking area, a patch lovely of trout lilies greeted us by way of bidding our group good-bye. These plants had quite a few leaves, more than the usual two per blooming plant.