Sunday, October 25, 2009
10-21-09 Felsenmeer
I played hooky from work on Wednesday (10-21-09) in part because the weather forecast indicated it would be the only decent hiking day for the rest of the week and woould be similar to last Saturday which was a peach. There'll be more good days to come: warm, calm, and clear, but not always when you can get out of work and on to a trail. I got on the Ammonoosuc Ravine Trail around 9 am heading, first, for Lakes of the Clouds and then to the summit of Washington to look more closely at the 'felsenmeer' before the coming snow impounds it. I wanted more info to mull over this winter. The photo above is the trillium patch where early last June I took photos of the red trilliums (T. erectum) that were growing profusely in this very spot.
Getting on the trail in the winter is more painstaking then the summer. You really have to spend time thinking about what you're going to take and the winter backpack is always heavier than the summer pack for obvious reasons but it's always a shock how much you have to carry and how much more work it is.
The Ammonoosuc River is thriving and as melodious as ever. The water's so clear in the late fall and winter before its completely buried, its voice muffled, under layers of snow and ice. As I headed up the mountain I'm reminded that these huge blocks of Littleton Schist in and along the river are disparate representatives of the felsenmeer that traveled this far down Ammonoosuc Ravine brought by gravity and possibly, during great storms, by the force of water and gravity combined.
The forecast at 5 am when I left home was for seasonally warm temps, a bit of fog in the morning, then partly cloudy with winds of 15-25 mph. From the moment I got on the trail it looked like the forecast would ring true. Looking up into Ammonoosuc Ravine the cloud cap was sitting at about 4,000 feet and seemed to be lifting gradually.
By the time I reached the head wall of the ravine the cap had lifted a tiny bit allowing this view to the northwest towards Cherry Mountain but the clouds seemed to be settled in for a longer seige then just a few hours. I thought of bailing out of the hike but kept climbing even though a dense cloud cap, wind and cold temperatures would make it a bit of a challenge to to see much and be able to explore high on the summit cone and take photographs. When I used to rock climb ages ago I heard this quip in Scotland from a seasoned mountaineer: "Well, we struggled up the wet rock, climbing higher and higher in the cold and rain and fog wondering if it would ever stop when suddenly a voice came down to us out of the clouds and in a deep voice urged us on saying, 'Cheer up. lads! Things could be worse!', so we cheered up and sure enough things got worse."
10-21-09 The Mystery Around The Felsenmeer
A closeup of a crack shows the simplicity of how it works. Water flowing downhill and carrying small bits of sediments is the usual agent that starts the crack, through erosion, and continues the process of deepening and widening the crack(wind plays a key role as well). Organic matter gets mixed in with sand to form the rudiments of soil. The soil, even if it's infinitely thin, will attract a seed, or two, that will immedately begin the colonization of the "niche" and then it is just a question of time before a more intense force is exerted on the parent rock. The freeze-thaw cycle is incredibly powerful. It's can lift tall buildings and destroy highways. I had a job years ago installing underground propane gas tanks to fuel heaters for large outdoor swimming pools that weighted tons. If there was frost in the ground and the tank wasn't filled immediately with propane the day it was buried the next day it would be sitting on the surface, pushed right out of the ground by the frost.
Ice. This is thin ice, 'verglas' in French, and merely an inconvenience. It comes and goes through the fall. However, if there's significant rain and a freeze then the trails become rivers of hard ice. This, alas, if fairly common in New England mountains. It means, primarily, that for hiking good 'traction' is needed to negotiate trails in the high country. This usually means crampons or good alternatives. I always carry a pair of light weight, strap-on crampons and wear the items in the photo below which are pull on. They have chains with hardened stainless steel cleats attached and offer a good enough purchase that you could use for some minor ice climbs. It's always good to have back up traction.
A month ago this was a much different scene. In a few days this could all melt, too, leaving the impression that it wasn't winter-like a few days past. To hikers who were on the mountain while the snow fell and the trail turned to ice it felt in every way like the dead of winter.
Here's where the tension began between the day's forecast and reality. It felt and looked like it was going to clear, or maybe it was just hope.
I was close to the ridge and the cloud cap should have dispersed leaving higher clouds scudding over the summit. And at moments it certainly looked as if the cap would tear itself apart and vaporize so that the summit would stand in the clear.
The reality was that this is as good as it got for the entire time I was on the mountain. It's certainly not terrible but after being spoiled recently by one or two brilliant days it's frustrating.
That's Lakes making a dramatic appearance as it emerges for a moment out of the clouds. At 5000 feet the air was several degrees colder even out of the 35 mph wind in the lee of the hut.
I left my pack at Lakes and climbed Monroe to keep warm and got into thicker and thicker fog. I went east on the Crawford Path to see and photograph the locations where the Dwarf cinquefoil, Potentilla Robbinsiana, plants were growing that I tracked through the summer. That bare spot in the photo is the small 'tarn' I had photos of in the blog several times during the summer.
Quite a bit of snow had bulked up on the leeward side of Monroe as well as in the trough made by the trail and in the krummholz.
The krummholz was icing as a result of precipitation and in this case it was most likely snow that had sublimated into ice or been turned to ice by the moisture in the wind. The ice builds gradually on the side of the plants towards the wind.
This is one location for several Robbinsiana's that grow close to the Crawford Path and outside the federally restricted area informally called Monroe Flats.
A close up of the lower right corner of the above photo shows the location of one of the Robbinsianas and it's not visible being an 'annual.' I was surpised that with the amount of snow the mountain received to date that the areas where the Robbinsiana is successful are not packed with snow throughout the winter season. The plants visible in the photo, some with red colored leaves, are Potentilla tridentata, or three toothed cinquefoil, a close relative of the Robbinsiana. There's also a leaf of Mountain Avens, Geum peckii, that has turned a pale orange color.
This is the nominal ground where you will find Robbinsiana. The tiny plant was all but wiped out of its precious niche here on Mt. Washington so that by 1984 there were less than 100 individual plants. Through a long, challenging collaborative effort the plant has been restored and has a large, thriving population at the moment. The biggest threat to the plant at the present time is the hard soles of hiking shoes on the feet of hikers who stray off the trails in the vicinity of where the plant grows.
Map lichen, Rhizocarpan geographicum, in a yellow mood. It stood out brightly against the dark, cloudy morning.
10-21-09 Will It Ever Clear Up?
This is Littleton Mica Schist as it looks as 'felsenmeer'. On clear days with greater visibility it lives up to its German name, "sea of rocks", because the blocks of the mica schist cover vast areas of the Presidential Range north of Mt. Franklin and Mt. Monroe. It covers probably a little more than 60 percent of the total area of the northern peaks.
I need to do more research on the chemical and physical properties of the Littleton Schist but I do know that after lying for millions of years on the floor of the ocean for millions of years as highly compressed sedimentary formations it was metamorphized about 300 million years ago when most of New England was lifted up off the sea bed by compression from tectonic plate movements and collisions. Since the Littleton Formation is not igneous (volcanic) it doesn't fracture on straight molecular planes the way some igneous rocks do so the blocks are irregular and of random shapes and sizes. Few of the fractured rocks within the felsenmeer could be described as having having straight edges but are occasionally nearly flat surfaces. The crack in this mica schist block is pronounced. It is difficult to walk across the felsenmeer.
Felsenmeer as a term also applies to these 'fields' of smaller rocks, also pieces of the Littleton Formation. In this photo and the one below there is little consistency in the sizes of the stones. They're randomly sized and some are stacked on top of each other as if a stone wall fell down. It would be much easier to interpret these landscapes if we knew that the glaciers brought these rocks here or that giants once lived here and tossed them around for sport and then left them all here for later use.
Goldthwait and others researchers have theorized that the felsenmeer is post glacial in origin because it wasn't polished or gouged by the glacier. Goldthwait estimated that as much as 500 fet of pre-existing 'material', e.g rock, gravel, and soil, were removed from the White Mountains by the last continental glacier. That's a lot of stuff! Anyway, that meant the parts of the rock mantle that were left when the glacier ablated were, the part that became the felsenmeer, was no longer compressed either by 500 feet of rock ledge or 1000-2000 feet of solid ice bearing down on it. I'm curious whether this release of compression, or the compression prior to release, had anything to do with the mechanical aspects of the formation of the felsenmeer.
As the glacier melted during ablation enormous quanities of water were released that must have created impressive cataracts, rivers bigger than the Ammonoosuc, that leapt down the high peaks to the valleys. I'm curious, too, how that may have contributed to the formation and/or movement of the felsenmeer.
This photo shows the irregular shapes as well as the irregular edges of the rocks. Some edges are rough while others are more rounded, or what we would call 'weathered' but the weathering of these is irregular. The various lichens crusting the surface of these rocks are another feature of the felsenmeer that is important to think about. These plants are a possible clue to the timeline of events in the formation of the felsenmeer.
I walked off trail and zig zagged up the cone looking for a good site to set up a long term research project that begin by mapping an area of felsenmeer exactly using GPS to see if anything moves over a long stretch of time. Goldthwait's use of photographic data is not really conclusive in the long run. Using a site near the Cog tracks, too, would create questions about research data and the possibilities of intervention by humans and machines. The photos give some meaningful information but certainly are not as reliable as more precise measurements.
In this photo you see the egg shaped rock that appears in the last photo where it looks like it broke and fell away from the ledge. This is taken at the bottom of the cone. There's not much slope so gravity is not a large factor. A few questions: did the egg shaped rock actually break away from the larger mass of parent rock and if it did why is it so rounded? If not, where did it come from? I can't answer any of the question, I'm afraid, but I'd like to be able to.
I went up the cone to within a 100 feet of the summit but the fog was more opaque and the daylight dimmer than 500 feet below. At any rate half way up the a gentle side of the cone the rocks were aligned differently than on the flatter sections of the mountain. Gravity is obviously a more noticeable factor here. A glimpse of this formations gives an impression that the rocks here have potential energy and not merely resting here for eternity. They look as though they're just resting before rolling again.
I'll end the exploration with this photo of all the rocks stacked up in a formation near the bottom of the cone and ponder how that happened. One image that comes to mind is popcorn as though the blocks all fractured at once, leapt in the air for a second and then came to rest in these kind of unruly positions. Tfahe phenomenon of the felsenmeer is fascinating from the standpoint that during all the summers I worked in the mountains, traversing this very spot thousands of times, I never thought about the rocks one bit except to hope that one wouldn't move in some way to pitch me off as I jumped from one to the other.
Had enough of the felsenmeer? coming down out of the cloud cap I was greeted by a different world then what I'd left an hour earlier. The sun felt like cashmere. The weather felt as though it might go all the way and clear completely and be a fine October day and I began to regret having to go down. That's Mt. Monroe with Lakes of the Clouds nestled at it's feet.
When I see these remnants of tundra I have to ask whether this is an ancient landscape, say 100 million years old, or, a fairly modern one, say under 11,000 years old or since the last glacial sheet ablated here. At any rate in this photo you see the Littleton Formation as ledge protruding above the 'lawns' of, in this case, bigelow sedge which are for the most part resting on a glacial till soil itsel a remnant of the glacier. I'm curios what it would look like if you could peel some of the felsenmeer including the small rocks from a good sized area in the northern Presidential Range. What is underneath all that rock? The lawns may be relatively recent, but it is likely that tundra existed here for ages before the last glacial sheet extended south. It would be interesting to measure some of the lawns precisely and discover whether they are changing in size on all axes of the individual plots and also in total area. Are they expanding outwards in some areas, staying the same, or shrinking and dying back?
This goes back to the question of the balsam fir that I constantly hark back to and the progress the fir has made at some higher elevation sites like Zealciff, Carter Dome and Mt. Hale. A number of articles from the early 1900s on the ecology of the White Mountains and Mt. Katahdin in Maine, suggest that eventually all the mountains in New Enland will be forested to their summits. This will occur, it has been theorgized, regardless of wind and other aspects of the weather we think of as limiting factors for growth, and that it is a natural, successional process. The lawns could be a fundamental step in that succession.
The larger of the two lakes where it lies at the foot of Mt. Monroe. The clouds moving in were the front runners of another storm system coming in from the west.
The smaller lake, again, with some weak sunshine on it. You can see the cloud cap on the the upper ridge extending towards the summit.
Lakes again with a measure of the snow that drifted in. By mid-January the whole front yard will be a huge snow drift rising above the roof line.
As I began my descent clouds were still coming in at 5,000 feet and a higher layer was beginning to congeal.
The clouds around the summit often looked as though they were about to vaporize in the warmth of the sun but when I got down to the Cog station the cap was solid and about where it was in the morning.
Fall colors linger on Mt. Dartmouth (right) and, all in all, the light and clouds are still of the fall but you know it's not for long, that winter is almost here and it won't be long before we'll be able to ski down Ammonoosuc Ravine.
Thursday, October 15, 2009
10-09-09 Zealand in the rain
I mentioned meditation. Hiking is often a meditation for me but on Friday my brain was busy wading around in the data I've gathered so far with my research "project" on the Gale River Trail slide. The project is half complete. I was also trying to make sense of the complexities around "felsenmeer creep" which I'll explain later. With the research project I'm at that point where it feels like I've opened up more questions then I'm ever going to resolve. That's the primary reason I haven't finished the blog entry on the research: I haven't been able to draw any conclusions.
I've been re-reading Richard Goldthwait's papers (1939 & 1968) on glaciation in the White Mountains but I also stumbled on an article titled: "The Shape of New England Mountains" by Will F. Thompson serialized in the December issues of Appalachia from 1960 to 1962. Thompson's piece is long. According to the introduction the article was his doctoral thesis. It's an energetic analysis of some of the current theories (of that time) regarding the physical geography of the White Mountains but his main intent seems to be to challenge some of Goldthwait's theories. He does this with so much gusto that he gets lost in that endeavor and loses what could have been a brilliant collaboration with Goldthwait. Thompson talks a bit about "felsenmeer creep", an aspect of mass wasting, describes the gravity-driven incremental downhill movement of the large rocks on the summits and flanks of the northern peaks of the Presidential Range. A term appearing in Thompson's and Goldthwait's papers, "solifluction", applies specifically to the incremental downhill movement of soil in areas of permafrost where there are seasonal freeze-thaw cycles. Solifluction can move fairly large stones even down slopes of only a few degrees steepness meaning the process is not as gravity driven as 'creeping' is. There is an equal, or greater. force exerted by the freeze-thaw mechanics.
There's agreement that 'creeping' as it applies to 'rock glaciers' (eg applied to Kings Ravine), and 'solifluction' play major roles in the movement of the large rocks comprising the felsenmeer. But how and when the felsenmeer came to be in its present form is at best an educated guess. We still have no idea about the time line of when and how long it might have taken as well as the details of the kind of climate, local or global, that would have caused the parent material to fracture and then move to the degree that it has particularly where the large blocks stack up on one another. I'll come back to these conjectural aspects later because I think they're fascinating.
In graduate school I studied "leaf litter" from sites around the northern hemisphere: the US, Canada, Scotland, France, Germany, Scandinavia, Russia, and Japan. The leaf litter samples were "ashed' in kiln-like ovens and measured with an atomic mass spectrophotometer (the device was not nearly as elegant as its name) that measured their cation content in parts per million. Cations are positively charged atoms. (Anions are negatively charged atoms.) Tree species in the broad-leaved categories differed only slightly from each other in the principal cations like calcium, sodium, potassium, copper, (the light metals) etc. For instance most trees in the maple (Acer) family usually tested with slightly higher levels of calcium than the oak family (Quercus). Oaks generally grow in dry (warmer), more acidic soils that are deficient in calcium. The amounts of these cations in all the samples reflected the parent soils which in most of those countries were of glacial origin like the soils in the White Mountains. I should add that almost all of the leaf litter samples I looked at were acidic, some more than others, with pHs of 6.5 to 5.5. If I remember correctly the oaks, particularly red oak (Q. rubra) leaf litter was the most acidic out of those samples.
Each year leaves are laid down, distributed, and then redistributed by the wind in random patterns on the forest "floor". I like say to young students that the wind is like Robin Hood redistributing the wealth. Rain, snow, and wind continue to flatten the leaves until they are like a carpet or mat next to the top layer of soil. They begin to decompose the moment their apical meristem breaks and the leaf falls from the trees that bore them. At that moment the sugars in the leaf begin to break down. The leaves closest to the soil will decompose first, within a year or two, and their cations will be taken up by the soil and eventually redistributed as minerals, like the calcium, that will be taken up again by the tree's roots in a (more or less) continuous cycle (part of the larger mineral cycle). Its a soil based economy. I often say that soil is our only real wealth. Alan Savory likes to say that all the wealth on earth comes from the sun.
Aldo Leopold, in "Sand Country Almanac", devotes a chapter to the wanderings of a single sodium atom through millions of years of geologic time. It's a great narrative! The sodium (like the sodium in our table salt) is introduced to us lodged in a massive glacial moraine next to a river in what is now western Canada. Suddenly a herd of giant bison crashes over the lip of the moraine scattering the gravel and sand which avalanches down into the river at the bottom of the steep slope. The sodium atom then follows an extraordinaryodyssey in which it sometimes lies in limbo for millions of years before being animated as a blade of grass, a deer, a tree, a muskrat, etc, not exactly 'alive' itself but integral to life in its various forms. At the end of Leopold's narrative the sodium atom is doing well, residing in sands on the Mississippi River delta waiting for its next transformation.
Plants have several thresholds. Soil acidity isn one. Some plants can tolerate more alkaline soils and some more acidic soils. Soil pH can vary in small areas depending on wetness, slope, amount of sunlight, and underlying geologic features. Other thresholds are temperature, moisture, length of the night (skotoperiod), and density of shade.
The most productive soils tend to be "circumneutral" (the term means close to a pH of 7, with pHs between 5.4 and 7.5 on the pH scale.) They usually occur where there's an underlayment of limestone. Limestone is calcium carbonate. The calcium is positively charged and will neutralize acids and "sweeten" the soil, an old term meaning to make it less acidic and more akaline. Circumneutral soils are associated and can be identified by several "indicator" species of plants like ginseng (Panax quinquefolia), goldenseal (Hydrasta canadensis), and maidenhair fern (Andiantum pedatum) which only grow where the pH is close to median of 7. There are a few sites west of the WMNF towards the Connecticut River watershed where there are circum neutral soils and that are near limestone outcrops. There are none that I know of within the WMNF.
This one looks like a shaggy, old buffalo. It takes decades for the blow downs to decompose and turn back into soil. This one fell some 20 years ago and is only at this stage of decomposition. Once they're fully decomposed there will still be an "imprint" where they fell. There will be a slight mound where the roots finally settled and a slight depression where the root ball was torn out of the ground. These mounds and pits are noticeable for decades after a "century" storm like the 1938 hurricane when thousands of trees were uprooted throughout New England.
I think these are Trametes versicolor (could also be T. pubescens), or turkey tail mushrooms that are efficient agents of decomposition. Mushrooms, fungi, are the primary organisms of decay in the forest. Turkey tails are so good at decomposing plants they have been studied in hospital laboratories to see if they can be used to destroy cancer cells in humans.
This blow down wasn't here three weeks ago. It's lying right next to the trail. I nicknamed it "the beast" and it'll be interesting to see how long it takes to decompose.
I call these dense thickets of balsam fir seedlings "nurseries". The density of balsam fir seedlings is astonishing. They're everywhere you look and ready to take over when a tree in the over story dies or gets blown over which is fairly frequent in this climate.
This is a stand of balsam fir that grew from nursery stock of 15-20 years ago and is being supplanted by a new generation of balsam fir seedlings growing underneath it.
A family on their way into Zealand Hut for the night. It's their first trip to a hut and their first passage on the Zealand Trail.
The beavers are trying to act like deliquents and take out the zig-zag bridge. In the past month they've been adding material to some of the old dams close to the trail where it crosses the bridge and they've raised the water level in preparation for winter. Having deeper ponds makes their winter homes (lodges) more secure and makes it easier to procure food in the winter as well by expanding the margins of the ponds into the trees at the edges of the pond.
This is an old beaver pond that is returning to forest. The larch trees (Larix laricina) in the middle of the opening are indicators of a new succession stage of the return of this open space to forest. The succesion began with alder (A. rugosa, A. crispa) which can still be seen around the edges and throughout the field along with dense clumps of various grasses, sedge and roseate plants. Alder, although not a legume, is host to a bacteria located in the roots that fixes nitrogen so it is a valuable soil building species. Alder fixes nitrogen at a comparable rate to the peas you grow in your garden which are legumes and fix nitrogen that increases the fertility of the garden soil. Alder is a generalist and will grow on a variety of ecological sites. Beavers like it. Moose like it, too.
The larches (also called 'tamarack'. The Abenaki word for it is hackmatack) growing on the island are fairly old, probably close to 35-40 years old and indicate the age of this pond as being a decade older than that. I have pictures of the pond dating back to the mid-1960s. The fact that beavers are active here again is significant as it begins a new cycle of growth that will impact the valley for decades to come.
The larch are unique because they are conifers that shed their needles each year. Their color turns from green to yellow and orange like some of the deciduous trees, and the needles drop all at once. Other confers drop their needles sporadically. Because of the volume of needles the larch dispense every year they are capable of building soil right where they grow.
Larch is a medicinal plant like gingseng and goldenseal mentioned above. It was widely used for making a tea used as laxatives, and another tea to use as a mouth wash for sore throats, and it was also popular for making snowshoes.
I was really pleased this week when the Nobel Prize for Economics was awarded to Elinor Ostrom of the University of Indiana for her work on The Commons. Her book "Governing the Commons" had a huge impact on me and others who are concerned about demise of The Commons and who are working towards a greater public understanding of what The Commons represent. Awarding her the Nobel is timely, or at least I see it as a sign of hope, because it means the Nobel Prize committee recognizes the importance of The Commons.
"Governing the Commons" was published in 1990 (see the bibliography in the side panel) and a reviewer at that time wrote:
"Ostrom uses the term "common pool resources" to denote natural resources used by many individuals in common, such as fisheries, groundwater basins, and irrigation systems. Such resources have long been subject to overexploitation and misuse by individuals acting in their own best interests. Conventional solutions typically involve either centralized governmental regulation or privatization of the resource. But, according to Ostrom, there is a third approach to resolving the problem of the commons: the design of durable cooperative institutions that are organized and governed by the resource users themselves.
"The central question in this study," she writes, "is how a group of principals who are in an interdependent situation can organize and govern themselves to obtain continuing joint benefits when all face temptations to free-ride, shirk, or otherwise act opportunistically."
"Governing the Commons" was the first intelligent and comprehensive response to Garret Hardin's tragic essay, "The Tragedy of The Commons" published in 1968in which he focused on his belief of the need for a centralized governance to stop population growth on the planet by limiting the number of babies a family could have. His centralizing point, a metaphor regarding The Commons, was ill-advised and he stated they were never managed and left open to greed, exploitation, and poor management leading ultimately to the degradation of resources. He created the impression that managing The Commons was impossible and that The Commons themselves were a frivolous idea.The rain stopped when I arrived at the meadows and a pale sun emerged through the clouds and there was this beautiful gold highlight on the trees and grass. This meadow is where, a hundred years ago, there was a large logging camp and switching yard for the locomotives that hauled logs through the Valley.
Hardin's mis-interpretation of The Commons and his preference for centralized control represents a majority opinion in this country. Few people seem to "get" the idea of the commons even though a few of the states like Massachusetts and Pennsylvania are "commonwealths" and most of us live in some form of "community". In the decade of the 1990s I worked in The Commons, mainly with native groups in Canada, the US, Nepal, Kenya and Ecuador, trying to get a working idea, a concrete method, for restoring The Commons. At one time, and today in some native bands, The Commons were the existing "infrastructure" that's been replaced by private enterprise and, now, the global economy, neither of which recognize The Commons. What Hardin missed was that The Commons, for the most part, were well regulated against greed and exploitation, the very things we see in private enterprise and the global economy today.
Elinor's solution, the third alternative, is what I refer to as the Indigenous Model for governing The Commons. Indigenous people regulated and supervised the The Commons wisely (for the most part), a task given to the groups Elders. Working with the Cree, Innu, and the Iroquois around different facets of the commons I always saw a balance of power in governing The Commons between the chiefs and the Clan Mothers. Private enterprise, contact with the modern economy, is causing a weakening in this balance. The Commons to these groups is land, water, food, food production or procurement, as in the caribou hunting areas of the Innu, and the germplasm, or seed, supplies of the Iroquois. (All seeds and germplasm should be owned in common. DNA should be part of The Commons. It's sad but it's all about money.) In the US a war erupted in Wisconsin a few years ago over the fishing rights of the Anishinabeg (Chippewas and Objibwa). That was a fight to sustain The Commons against a political jurisdiction's (the State of Wisconsin) desperate need for cash. This will happen more and more. Looking at the beaver dams, the reforesting of an old beaver pond, the death, decay and recycling of leaves and trees, you get an idea of a far more sustainable economy and a wisdom that is being thrown away, lost.