What Is A Tree Line?
Jul 28, · Alpine treeline is the transitional ecological zone between spruce forests at lower elevations and alpine tundra at higher elevations. Because cold temperatures limit tree establishment at high elevations, the alpine treeline zone is hypothesized to be especially sensitive to climatic warming. Treeline in Denali is found at an elevation of about m ( feet) on cool north-facing slopes . The tree-line or timberline is the edge of the habitat at which trees can grow. Beyond the tree-line, they are unable to grow as conditions are too bad. There are several types of tree lines defined in ecology and geology: Arctic tree-line The farthest north in the Northern Hemisphere that trees can grow; farther north, it is too cold. Antarctic tree-line The farthest south in the Southern Hemisphere that trees can grow; farther south, it is too cold as well. Alpine tree-line .
Trees are some of the most resilient plants in the biosphere and are capable of colonizing almost all terrestrial habitats with even the harshest of conditions. However, trees are living things and have critical conditions necessary for their survival, and when tree growth reaches areas deficient of such conditions, their growth reduces gradually until it ceases altogether. The stretch where this transition happens when viewed from a distance seems to be a clear boundary is known as a tree line.
However, tere viewed on the site, the transition is gradual with the vegetation cover receding and trees becoming shorter and far in whxt. The tree line is evident in locations where the elements of temperature, soil type, topography, precipitation, snow, altitude, and the wind have a profound effect on the environment.
Tree lines whxt classified according to the locations where they are found. Alpine tree lines are found at whhat altitudes eleevation which trees cannot survive and is usually found on mountains. The climate found beyond the alpine tree line is known how to remove egg smell from well water the alpine climate with terrain called alpine tundra.
There are two main factors that inhibit the growth of trees beyond the alpine how to make money in stock line: the decreasing air temperature which can be about 2 degrees per 1, feet of elevation and the presence of snow and ice which what is the value of nickel metal the biological functions of trees. The altitude where the alpine tree line is present varies in mountains depending on wgat proximity to the poles.
The further a mountain is from the poles, the higher the altitude the tree line begins and vice versa. The alpine tree line is not a clear-cut boundary as seen from a distance and one will find sparse tree growth in scattered areas of the tundra terrain. Alpine tree line can also be evident in leeward facing what elevation is the tree line of mountains which have minimal rainfall.
The decreasing precipitation levels create conditions that are not favorable for tree growth, and elevatiin tree line can be seen in such an area. Deserts present some of the harshest conditions for any plant to grow which include extreme temperatures, low to zero precipitation, and dust storms. The tree line in desert landscapes are not clear, and tree growth will decline gradually before finally turning into shrubs and bushes. Desert tree lines occur at low altitudes of about 5, feet above sea level.
Several studies have linked human activity to the occurrence of tree lines in numerous locations all over the world. Pollution is the biggest artificial factor that limits tree growths and therefore causing tree lines. The Kola Peninsula tree line in Russia is a perfect example and is linked to the presence of the nearby copper smelter which is one of the largest in Russia and is llne for emissions of many pollutants majority of which contaminate the neighboring forests, inhibiting the growth of trees.
Deforestation is another artificial cause of tree lines where vast tracts of forests are cleared for the human activity which cuts off the ghe of trees pine such areas. The tree line near Mt. Rainier, US. Benjamin Elisha Sawe April 25 in Environment. What Is Algal Bloom? Kelp Forest. Carbon Cycle. What Is A Cloud Forest? What Is A Carbon Sink? What Elsvation Bycatch? The Water Cycle.
Jan 21, · The alpine timberline marks the point where the elevation is too high, and usually too cold, for tree growth. The city of Vail, Colorado, is located near an alpine timberline in the Rocky Mountains. Trees along the Vail timberline include quaking aspen and lodgepole pine. The desert timberline marks the point where the soil is too dry for tree growth. Youll find this kind of timberline at very low elevations, usually below 1, meters (5, feet). Apr 25, · The tree line in desert landscapes are not clear, and tree growth will decline gradually before finally turning into shrubs and bushes. Desert tree lines occur at low altitudes of about 5, feet above sea level. Human Activity And Tree Lines. Aug 04, · The elevation at which trees can no longer grow, also known as treeline or timberline, is different in various places around the world. For instance, the timberline is at 10, feet in many parts of the western United States and as low as 4, in eastern states like New Hampshire. Some places in Mexico have a treeline as high as 13, feet, while the line is only 5, feet in most areas near the Sonoran Desert in Mexico.
Treeline in the East is lower than out West. Photo by Thomas Jones. Trees grow where they can. And they are surpassingly capable, making do in an impressive array of conditions around the globe, including many harsh places. But there are limits to their versatility. There are some natural environments where trees simply do not grow, thrive, or even survive, such as near the tops of the bigger mountains.
As you hike up a big one, you can see many gradual changes in the composition of the forest. Eventually the diversity of species plummets, the trees are much shorter and more scattered, and at last they look more like shrubs.
Then, at some elevational limit in any mountain locale , the trees stop. This is the alpine elevational treeline, although it is very rarely a distinct line. Treeline is more commonly an uneven zone of transition from scattered shrubby trees to treeless areas with but a few specialized — and very tough — herbs and a hardy crust of lichens. The transition occurs unevenly because there may be sheltered and sunnier local conditions — various crevices, coves, and crannies — at higher elevations where trees can still make it, thus extending the upper limit of the forest here and there.
Indeed, topography, soils, precipitation, and exposure to sun, wind, snow, and ice all play important roles in determining which trees grow where and how well.
But temperature generally decreases with increasing elevation and latitude , and many ecologists suggest that low temperatures — which limit growth in general — seem to be the single most critical factor in determining the upper elevational and latitudinal limit of trees.
Alpine and arctic environments are marked by seriously harsh winters. And while trees there do take a beating that severely limits their growth, some species have made amazing adaptations to withstand such winters. But to do so, they need a sufficiently long summer growing season — free of snow on the ground and with adequate temperatures — to earn a living that they spend all winter long.
The problem at higher elevations and latitudes is that the growing season is not only colder but also shorter. It starts later at higher elevations because spring bud break is so closely tied to the temperature of the soil, which takes longer there to warm up.
The elevational limit of such suitable summer conditions varies by latitude. In Mexico, for example, treeline occurs somewhere around 13, feet, whereas farther north, in the Tetons, for instance, it occurs lower, at approximately 10, feet. But how then to explain the elevation of treeline in the White Mountains of New Hampshire? Mount Washington sits at a latitude comparable to the Tetons, but its treeline is at roughly 4, feet. Is it because the Presidential Range has frighteningly bad winters that blast needles right off trees with screaming bits of ice?
Sure, wind plays a part in limiting tree growth, by desiccating needles, scouring away thin soils, and directly damaging limbs and twigs. But winter is brutally hard in the Tetons, too, and nearly as windy. The difference, instead, may have more to do with summer conditions, when trees have their only chance to germinate, grow, and reproduce.
Because the Tetons are inland — and are so much more massive — their summers are warmer and drier than in the White Mountains, which are closer to the coast and therefore have cooler and cloudier summers.
On Mt. Washington, in fact, there has never been a temperature recorded higher than 70 degrees. Because the elevational treeline is so closely tied to temperature, many suggest that it could be a particularly sensitive indicator of global climate change.
Presumably, rising temperatures would increase the elevation of treeline in any locale, altering forest distribution and potentially ousting rare plant communities — and their inhabitants — that now exist above treeline. Although the specific physiological mechanism of treeline formation is not fully understood, there is growing photographic and other evidence of upward shifts in treelines worldwide.
Why does it take longer at treeline for the soil to warm up? Is it a difference in the soil? Soil moisture? Air temperature? Or at least 3 of 4. Snowpack certainly would have an effect more snow means longer snow means colder soil. Cooler ambient air temperature certainly contributes.
His explanation about is not correct. The reasons for the summers being moister in New Hampshire than Wyoming have nothing to do with proximity to the coast, since summers are also drier on the Pacific Northwest coast and every place else in the west. The answer is which elevation results in a minimum winter temperature of C. That is the temperature that causes ice to form in plant cells and kills trees.
Because of the arctic fronts that move down from Canada, those temperatures occur more in the Northeast than the west. It takes one rising to 10, feet in Wyoming to routinely achieve those temperatures.
By the way, treeline is only 5, feet in mild Washington, where temperatures rarely drop below 0F even in the mountains. Huge deep snowpacks that bury trees till July. I grew up in interior Alaska where temps went well below C and treeline is higher than along the coast which has a more moderate temperature. And the answer is…large scale atmospheric circulation. The westerly winds coming of the Pacific Ocean are deflected over and around the western mountains forming a mean-annual standing wave across North America.
Although the overall configuration of the wave pattern changes somewhat with the seasons, it is generally characterized by a ridge of warm air over the west, and a trough of cold air over the east. Treeline altitude is mostly dependent upon summer conditions it occurs over a zone where average summer temperature is near 5 degrees C. This affords hot, dry air masses. If the land areas of the interior west were near sea level, summer temperatures would range from 30 to 40 degrees C; but given the high mountains and plateaus, temperatures are more typically between degrees C.
The northeast sees only a few bouts of subtropical highs each summer also part of the Hadley circulation, but humid due to moisture from the Gulf of Mexico and the North Atlantic Ocean , with the circulation instead being dominated by subpolar flow driven by a low pressure often forming over Quebec associated with the polar frontal zone; the low pressure drives the blessed northwest wind bringing cool, dry, clean air from Canada.
Summer temperatures near sea level in the northeast are on average around 20 degrees C. Ten to twenty degrees C cooler than expect near sea level temperatures for Wyoming and Colorado… And THAT is the fundamental reason why treeline is so low in the east relative to in the west.
These places experience brutally cold winters, but mild or even hot! The top of Mt. I also believe wind and altitude play a factor. Therefore trees on Mt Washington literally get blown off the mountain due to the much greater total energy of the winds. One other thought…. Spent my life teaching skiing. We were taught that the average daily temperature in July has to be above 50 degrees. This does neatly explain all the discrepancies in treeline elevation. I am a meteorologist and also love the mountains!
I agree with Mark. While there are many factors influencing the tree line altitude, the 50 degree F isotherm of the average temperature of the warmest month is the most reliable measure.
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