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As the Laurentide glacier retreated from the Champlain Valley 13,600 years ago, the ice damned the valley and Glacial Lake Vermont rose to about 170 m (550 feet) above sea level, which is the elevation of the camera. This sand and gravel was carried by an ice-marginal river that built kame terraces until it reached the lake where it dumped fine sediments into the standing water forming a delta more than 4 km long.
This quarry is the source of material that is spread on snow-covered roads in Salisbury. It is being sorted and stockpiled this month. Notes: I used a Nikon D40 with Nikkor 300mm f/4.5 AI-s lens, f/8, 1/160 second, ISO 200, NEF. 35mm equiv is 450mm. Field of view set to 3 degrees. |
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Pine-Oak-Heath-Sandplain Forest, Salisbury, Vermont -- Due to the presence of pitch pine, this is one of the rarest forest communities in Vermont, known only from the deltaic sandplains of Colchester (http://gigapan.org/gigapans/30324/) and this stand in the Salisbury Town Forest. The parent material for the droughty, acid soils is a 13,600 year old deposit of sand and gravel that is about 20 m deep here (an exposure of the deltaic strata under this surface can be seen here: http://gigapan.org/gigapans/34814/). Students at Middlebury College under the direction of Matt Landis have been describing the forest composition and population structure of this stand, and addressing questions about its disturbance history and the probable fate of the pitch pines. Results suggest that pitch pines have not reproduced in this part of the stand for many decades, and that many of the large pitch pines are dying. Most trees marked with flagging in this view are pitch pines.
Some botanical and technical information is in a comment. |
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Hemlock Forest in the Salisbury Town Forest -- Eastern hemlocks are responsible for more than 75% of both tree density and canopy cover in this stand, and hardwoods scattered among the hemlocks include three species of oak. The dark forest floor supports little more than mosses. Many of the trees here are about 200 years old, making it the oldest stand in the Salisbury Town Forest. A few trees are 300 years old, including two hemlocks in another GigaPan (http://gigapan.org/gigapans/35738/) and possibly the white oak near the center of this scene. Logging has occurred here (cut stumps are present in the stand) but it has been less thorough than most places in Salisbury and Vermont.
This stand occupies a southeast-facing slope with thin till-derived soils over Cheshire quartzite. Some botanical and technical information is in a comment. |
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Northern Hardwood Forest – Sugar maple and American beech are common in this stand and provide the yellow glow. Beech trees have reproduced by root sprouts far from the main trunks and form a dense sapling thicket. These saplings and some young sugar maples have held onto their yellowed leaves and brighten this scene after most canopy leaves have fallen.
The soil parent material at this site is silty deltaic bottomset beds deposited 13,600 years ago under 25 m of lake water near the mouth of a proglacial river. The abundant stones that were gathered to build the wall suggest a close proximity to the glacial ice that was constraining the spread of the ice-contact delta. Although most of the tree species here can live 300 to 400 years, few if any in this stand are more than 100 years old. The near side of the stone wall was an agricultural field until World War II. The far side has been a forest since about World War I, but was heavily logged in the last few decades. Some botanical and technical information is in a comment. |
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Mesic Red Oak-Northern Hardwood Forest, Salisbury, Vermont -- This well-drained kame terrace in the Salisbury Town Forest supports a dry example of this forest type with three oak species. The forest community is distinguished by the absence of sugar maple, an important component of hardwood forests on less droughty sites. It includes red oak, white oak, and chestnut oak, and I think at least one black oak (I have yet to get my hands on a leaf or acorn from it).
Some botanical and technical information is in a comment. |
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Dry Oak Forest in the Salisbury Town Forest. Thin, till-derived soil on this gentle south-facing slope supports a stunted forest of white, chestnut, and red oak. These species grow more than twice as tall elsewhere on deeper or wetter soils. Shrubs, herbs, and grasses take advantage of the ample sunlight passing through the sparse canopy. The similar size of the oaks suggests they are similar in age, and that they colonized the site after the previous vegetation was removed by logging or fire about a century ago. There are lots of seedlings of all three oak species, and if deer don't eat them, this forest type could persist here as the first generation trees mature and die.
More information is in a comment. |
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My apologies to those whose knowledge of the fierce territoriality of Ruby-throated Hummingbirds might make the above scene a perplexing distortion of reality. Rarely will the local male allow birds others than his mate to use a food source in his territory, so a feeding flock like this is impossible, and has a biological spookiness to it, like cloned pets. In a sense, the distorted reality is due only to the integration over time that is a feature of all GigaPan panoramas. It’s just highlighted here by selectively capturing the moments to integrate. This image is a record of one visit to my patio by a male (dark throat) and three visits by females (probably the same one).
In case Mom asks: EVERY ONE OF THE BIRDS IN THE PANO IS SHAUN WHITE (and his boo). (see http://www.gigapan.org/viewGigapan.php?id=15884) Notes: The Epic 100 did not capture any birds in the panorama, so afterwards I turned off the imager, set the D40 to continuous shutter at 1/1600 second and single area autofocus, and waited. One can get carried away with this, so I made sure to drop in birds (and insects) only where they were actually photographed in the scene. |
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Even at dinnertime there is some recreational activity on a warm Friday at Lake Dunmore. The lake marks the eastern edge of the Champlain Valley and the base of the first ridge of the Green Mountains. A stagnant mass of glacial ice probably sat in the lake's depression as the main lobe of glacial ice retreated to the north 13,500 years ago. The torrents of sediment laden meltwater from the retreating ice built kame terraces, alluvial fans, and deltas around the dead ice, but did not fill the entire depression with gravel and boulders. Lucky for us.
Notes: Photoshop was required to repair the sails. Stitcher notes are below in a comment. This panorama was updated on September 4, 2009 using a 300mm prime lens (http://gigapan.org/viewGigapan.php?id=32058) |
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The intersection of Routes 7 and 53 in Salisbury is in the center of this scene. In the past 230 years, the composition of these forests has changed from dominance by American beech, sugar maple, and eastern hemlock to dominance by white pine, sugar maple, red oak, white ash, and paper birch. This reflects the increased importance of tree species that are successful on abandoned farmland and logged forestland.
A panorama of this scene taken in October with a better lens is at: http://gigapan.org/gigapans/35627/ |
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Mesic Red Oak-Northern Hardwood Forest on a kame terrace in Salisbury, Vermont -- Large diameter red and white oaks in this small stand are the most valuable timber in the 130 acre Salisbury Town Forest. Many trees could provide veneer-quality logs, making some worth a few hundred dollars apiece. Although the canopy is dominated by oaks, the subcanopy trees are mostly red maple, and virtually no oak seedlings or saplings are present. The large oaks established at the turn of the 20th century when wild turkey and white-tailed deer were uncommon. Today, healthy populations of these animals eat acorns or browse oak seedlings, preventing oak regeneration. Harvesting the oaks could result in conversion of the stand to less merchantable red maple or beech forest.
More information is in a comment. |