2023tpo1阅读原文7篇

tpo1阅读原文第1篇地下水是指渗入到地下并将所有岩石孔隙填满的水。到现在为止，大气水是最丰富的地下水资源，是地下水在水循环中的一个环节。普通的大气水会从地表、降水以及湖泊河流侵入到地下。在再次冒出地下面是小编为大家整理的tpo1阅读原文7篇,供大家参考。

tpo1阅读原文 第1篇

地下水是指渗入到地下并将所有岩石孔隙填满的水。到现在为止，大气水是最丰富的地下水资源，是地下水在水循环中的一个环节。普通的大气水会从地表、降水以及湖泊河流侵入到地下。在再次冒出地表之前，这些地下水有时会长时间留在地下。最初让人觉得难以置信的是，在我们脚下“坚实的”土地中竟然有足够的空间能储存这么些水。

然而，地下水所需的储存空间多种多样。松散的砂子和砾石间有许多颗粒，如沙粒和小石子，它们之间的孔隙是最常见的储存地下水的空间。由这些颗粒组成的水床非常普遍，通常位于看不见的土壤下方，在携带粗糙沉淀物的湍急的河流曾流过的地方都能找到它们的踪迹。比如，冰河时代覆盖北美的巨大冰层逐渐融化，大量水从那儿流出。水里总会携带些石子、砾石和沙石，这些颗粒会随着水流的减速而沉淀，这就是所谓冰河期的冰水沉积。

现代也有冰水沉积，尽管规模相对较小。凡是有携带沙石的河流或者溪流从山谷流至相对平坦的地面时，砂石就随着水流速度的减慢逐渐沉淀;水流通常呈扇形扩散，它们所携带的沙石也会沉淀为光滑的扇形斜面。当河流汇入湖泊和海洋的时候也会有沉淀，这些沉淀最初在湖底或海底，但将来海平面下降或者陆地崛起时，它们就会分布于内陆，通常厚达几千米。

低地区域上的任何位置可能就是曾经的河床，后续被土壤覆盖而变成现在的样子。如果那些过去的河床和沙洲现在位于地下水位之下，一定会有大量的地下水浸在它们的沙子和砾石之间。

以上说的都是松散的沉积物，那些坚固的沉积物，也拥有以数万计的毛细孔来容纳水。因为最初颗粒间的缝隙通常并未完全被黏固的化学物质塞满，而且部分颗粒很可能在固化时或固化后被渗入的地下水溶解;结果这些砂岩最终变得和形成它的散沙一样多孔。

因此，不管沉积物是疏松还是坚固，它们中一定有空间。大部分结晶体岩石都非常坚硬，但也有例外，最常见的就是玄武岩，它是一种固化的火山熔岩，经常充满了微小气泡，从而变得十分多孔。

岩石的孔隙度就是指其中空间的比例。但需要注意的是，孔隙度与渗透率是不同的。渗透率衡量的是水渗透物质的难易程度，它取决于与单个空隙以及连接孔隙间裂缝的大小。

当充满水分的沉淀物或者岩石样本被放置在适宜的干燥环境中时，大部分的水分会流失，但仍有部分水会继续附着在坚实的表面上。要不是因为表面张力，这些水分也会立刻蒸发，仅留下完全干燥的样本。因此，试验样本的含水量既包括可以流干的水，也包括不能流干的水。

这两种水的相对含量因岩石或沉积物种类不同而改变，即便它们有相同比例的孔隙，还取决于孔隙的大小。如果孔隙很大，其中的水会形成水滴，太重足以克服吸引它的表面张力，就会流走;但如果孔隙够小，水会像薄膜一样，太轻无法克服表面张力，从而稳稳地附着在孔隙表面上。

tpo1阅读原文 第2篇

Timberline Vegetation on Mountains

The transition from forest to treeless tundra on a mountain slope is often a dramatic Within a vertical distance of just a few tens of meters, trees disappear as a life-form and are replaced by low shrubs, herbs, and This rapid zone of transition is called the upper timberline or tree In many semiarid areas there is also a lower timberline where the forest passes into steppe or desert at its lower edge, usually because of a lack of

The upper timberline, like the snow line, is highest in the tropics and lowest in the Polar It ranges from sea level in the Polar Regions to 4,500 meters in the dry subtropics and 3,500-4,500 meters in the moist Timberline trees are normally evergreens, suggesting that these have some advantage over deciduous trees (those that lose their leaves) in the extreme environments of the upper There are some areas, however, where broadleaf deciduous trees form the Species of birch, for example, may occur at the timberline in parts of the

At the upper timberline the trees begin to become twisted and This is particularly true for trees in the middle and upper latitudes, which tend to attain greater heights on ridges, whereas in the tropics the trees reach their greater heights in the This is because middle- and upper- latitude timberlines are strongly influenced by the duration and depth of the snow As the snow is deeper and lasts longer in the valleys, trees tend to attain greater heights on the ridges, even though they are more exposed to high-velocity winds and poor, thin soils In the tropics, the valleys appear to be more favorable because they are less prone to dry out, they have less frost, and they have deeper

There is still no universally agreed-on explanation for why there should be such a dramatic cessation of tree growth at the upper Various environmental factors may play a Too much snow, for example, can smother trees, and avalanches and snow creep can damage or destroy Late-lying snow reduces the effective growing season to the point where seedlings cannot establish Wind velocity also increases with altitude and may cause serious stress for trees, as is made evident by the deformed shapes at high Some scientists have proposed that the presence of increasing levels of ultraviolet light with elevation may play a role, while browsing and grazing animals like the ibex may be another contributing Probably the most important environmental factor is temperature, for if the growing season is too short and temperatures are too low, tree shoots and buds cannot mature sufficiently to survive the winter

Above the tree line there is a zone that is generally called alpine Immediately adjacent to the timberline, the tundra consists of a fairly complete cover of low-lying shrubs, herbs, and grasses, while higher up the number and diversity of species decrease until there is much bare ground with occasional mosses and lichens and some prostrate cushion Some plants can even survive in favorable microhabitats above the snow The highest plants in the world occur at around 6,100 meters on Makalu in the At this great height, rocks, warmed by the sun, melt small

The most striking characteristic of the plants of the alpine zone is their low growth This enables them to avoid the worst rigors of high winds and permits them to make use of the higher temperatures immediately adjacent to the ground In an area where low temperatures are limiting to life, the importance of the additional heat near the surface is The low growth form can also permit the plants to take advantage of the insulation provided by a winter snow In the equatorial mountains the low growth form is less

Paragraph 1: The transition from forest to treeless tundra on a mountain slope is often adramatic Within a vertical distance of just a few tens of meters, trees disappear as a life-form and are replaced by low shrubs, herbs, and This rapid zone of transition is called the upper timberline or tree In many semiarid areas there is also a lower timberline where the forest passes into steppe or desert at its lower edge, usually because of a lack of

tpo1阅读原文 第3篇

of the following can be inferred from paragraph 1 about the ground that we walk on?

cannot hold rainwater for long periods of

prevents most groundwater from

has the capacity to store large amounts of

absorbs most of the water it contains from

word “incredible” in the passage (paragraph 1) 1is closest in meaning to

word “out of sight” in the passage (paragraph 2) is closest in meaning to

away

visible

to paragraph 2, where is groundwater usually found?

pieces of sand and gravel

top of beds of rock

fast rivers that are flowing beneath the soil

spaces between pieces of sediment

phrase “glacial outwash” in the passage (paragragh 2) refers to

rivers

huge volumes of water created by glacial melting

particles carried in water from melting glaciers

of the following are mentioned in paragraph 3 as places that sediment-laden rivers can deposit their sediments EXCEPT

mountain valley

land

lake floor

seafloor

word “overlie” in the passage (paragragh 4)) is closest in meaning to

cover

change

separate

surround

phrase “So much for” in the passage (paragragh 5) is closest in meaning to

is enough about

let us turn to

greater concern are

is related to

word “plugged” in the passage (paragragh 5) is closet in meaning to washed

up

through

to paragraphs 6 and 7, why is basalt unlike most crystalline forms of rock?

is unusually

often has high

has a low proportion of empty

is highly

is the main purpose of paragraph 7?

explain why water can flow through rock

emphasize the large amount of empty space in all rock

point out that a rock cannot be both porous and permeable

distinguish between two related properties of rock

of the sentences below best expresses the essential information in the highlighted sentence in the passage (paragragh 9)? Incorrect choices change the meaning in important ways or leave out essential

tension is not strong enough to retain drops of water in rocks with large pores but it strong enough to hold on to thin films of water in rocks with small

in rocks is held in place by large pores and drains away from small size pores through surface

pores and large pores both interact with surface tension to determine whether a rock will hold water as heavy drops or as a thin

the force of surface tension is too weak to hold water in place as heavy drops, the water will continue to be held firmly in place as a thin film when large pores

at the four squares [█] that indicate where the following sentence could be added to the

What, then, determines what proportion of the water stays and what proportion drains away?

Much of the water in a sample of water-saturated sediment or rock willdrain from it if the sample is put in a suitable dry █ 【 A】But some will remain, clinging to all solid █ 【 B】It is held there by the force of surface tensionwithout which water would drain instantly from any wet surface, leaving ittotally █ 【 C】The total volume of water in the saturated sample musttherefore be thought of as consisting of water that can, and water that cannot,drain █ 【 D】

Where would thesentence best fit?

An introductory sentence for a brief summary of the passage is provided Complete the summary by selecting the THREE answer choices that express the most important ideas in the Some sentences do not belong in the summary because they express ideas that are not presented in the passage or are minor ideas in the This question is worth 2

Much of the ground is actually saturated with

that hold water were spread by glaciers and are still spread by rivers and

is stored underground in beds of loose sand and gravel or in cemented

size of a saturated rock’s pores determines how much water it will retain when the rock is put in a dry

often remains underground for a long time before it emerges

sandstone, basalt is a crystalline rock that is very

of unconsolidated sediments are typically located at inland sites that were once

tpo1阅读原文 第4篇

以ground作为关键词定位至全段最后一句，说At first sight土地是不可能有那么大的空间去容纳这些水的，at first sight第一眼看上去的意思是这个不是事实，而且事实刚好与这个相反，也就是说土地是有空间的，所以C正确

令人难以置信的，想到credit card信用卡，credit指的是信用或者学分ible或者able表示可以……的，credible可信的，incredible难以置信的，不知道的话看上题也知道是不可能

of sight表面意思就是在视野之外，也就是看不见， C和D都说看见，所以错。而且far away离得很远也不一定就看不见，所以也不对。不知道的话说beneath the soil在土下面，当然也是看不见之意，所以B正确

问的是地下水在哪儿最经常在哪儿发现，找到第二句中的the commonest spaces are……最常见的地方是blablabla，这个blablabla就是我们要的答案。在那些颗粒之间的空隙里，所以首先正确的答案应该是space，答案D是正确的

是冰川的，与冰川有关的，outwash是个合成词，表面意思就是冲出来的，不知道的读原文，原文说pebble, gravel and sand, known as glacial outwash，也就是说前面的三个都叫做glacial outwash，其中sand是一定知道的，不是水，所以AC错，更不是冰，B错，应该是包括沙子在内的一堆小颗粒

排除题，可在第一句找到flat land，在第二句的前半句Sediments are also dropped where a river slows on entering a lake or the sea找到C和D，A虽然有说到，但不是沉积物沉积的地点，所以要选的答案是A

表在……上，lie表躺，所以overlie的意思是躺在……上，也就是cover，原文说低地国家地上的任何一点都可能覆盖原来的河床，B改变C分开D围绕全都不对

much for表面意思就是已经很多了，也就是足够的意思，代入原文，说unconsolidated未固结的沉积物已经说了很多了，下面就说说固结的沉积物了，所以A正确，B和C都说我们马上要讨论的是未固结的沉积物，所以说反了;D表示与……相关，完全不沾边，错

的意思是插入，填满。原文说原来颗粒之间的空隙没有被混凝土怎么样，而前一句说固结的沉积物之间有很多能够存水的空隙，既然是有空隙，就说明没被填满，所以答案是filled up，A洗B拖曳D浸透都不沾边

以crystalline rock和basalt为关键词定位至第六段的最后一句，原文说大部分crystalline rock是固化比较好的，但basalt是个例外，说basalt更加porous，孔隙率更高，所以B正确

问的是第七段的目的，看本段的第一句，解释了孔隙度的概念，后来又说孔隙度和渗透率的概念不同，后面又解释了什么是渗透率，其实就是说着两个率不同，答案当然是区分这两个东西，D正确

原文的结构是如果孔隙大，就怎么怎么样，如果孔隙小，就又是另外一个样;选项B说反，应该是孔隙大的话水会流走;C孔隙大的时候与表面张力无关，所以不是both;D选项在若干处都偷换了原文的概念，完全不对

待插入句说多少流走多少剩下是什么决定的，所以之前必须得说一部分流走了一部分剩下了，原文最后一句才说到这个，所以D是答案。貌似B选项之前也说了流走和剩下，但B之后有个it is held there，这个it指的是前文的留下来的水，所以与上文过渡紧密，不能插入句子。

选项对应第二段的尾句和第三段的首句，正确

water对应第二段的第二句和第五段的第二句，正确

the size选项对应第八段最后一句，正确

剩下的三个选项都太细节，不具有概括性，不选

tpo1阅读原文 第5篇

Groundwater is the word Groundwater is the word used to describe water that saturates the ground, filling all the Groundwater is the word used to describe water that saturates the ground, filling all the available By far the most abundant type of groundwater is meteoric water; this is the groundwater that circulates as part of the water Ordinary meteoric water is water that has soaked into the ground from the surface, from precipitation (rain and snow) and from lakes and There it remains, sometimes for long periods, before emerging at the surface first thought it seems incredible that there can be enough space in the “solid” ground underfoot to hold all this

The necessary space is there, however, in many The commonest spaces are those among the particles—sand grains and tiny pebbles—of loose, unconsolidated sand and Beds of this material, out of sight beneath the soil, are They are found wherever fast rivers carrying loads of coarse sediment once For example, as the great ice sheets that covered North America during the last ice age steadily melted away, huge volumes of water flowed from The water was always laden with pebbles, gravel, and sand, known as glacial outwash, that was deposited as the flow slowed

The same thing happens to this day, though on a smaller scale, wherever a sediment-laden river or stream emerges from a mountain valley onto relatively flat land, dropping its load as the current slows: the water usually spreads out fanwise, depositing the sediment in the form of a smooth, fan-shaped Sediments are also dropped where a river slows on entering a lake or the sea, the deposited sediments are on a lake floor or the seafloor at first, but will be located inland at some future date, when the sea level falls or the land rises; such beds are sometimes thousands of meters

In lowland country almost any spot on the ground may overlie what was once the bed of a river that has since become buried by soil; if they are now below the water’s upper surface (the water table), the gravels and sands of the former riverbed, and its sandbars, will be saturated with

So much for unconsolidated Consolidated (or cemented) sediments, too, contain millions of minute water-holding This is because the gaps among the original grains are often not totally plugged with cementing chemicals; also, parts of the original grains may become dissolved by percolating groundwater, either while consolidation is taking place or at any time The result is that sandstone, for example, can be as porous as the loose sand from which it was

Thus a proportion of the total volume of any sediment, loose or cemented, consists of empty Most crystalline rocks are much more solid; a common exception is basalt, a form of solidified volcanic lava, which is sometimes full of tiny bubbles that make it very

The proportion of empty space in a rock is known as its But note that porosity is not the same as permeability, which measures the ease with which water can flow through a material; this depends on the sizes of the individual cavities and the crevices linking

Much of the water in a sample of water-saturated sediment or rock will drain from it if the sample is put in a suitable dry But some will remain, clinging to all solid It is held there by the force of surface tension without which water would drain instantly from any wet surface, leaving it totally The total volume of water in the saturated sample must therefore be thought of as consisting of water that can, and water that cannot, drain

The relative amount of these two kinds of water varies greatly from one kind of rock or sediment to another, even though their porosities may be the What happens depends on pore If the pores are large, the water in them will exist as drops too heavy for surface tension to hold, and it will drain away; but if the pores are small enough, the water in them will exist as thin films, too light to overcome the force of surface tension holding them in place; then the water will be firmly

tpo1阅读原文 第6篇

山上树带界线的植被

通常从山坡上的森林到没有树的苔原是一种非常戏剧化的转变。在一个垂直距离只有几十米的地方，树木这种生命形式就消失了，取而代之的是低矮的灌木、草本植物和牧草。这种快速过渡的区域被称为上行树带界线或林木线。在许多干旱的地区存在着下行树带界线，在这里由于缺乏水分森林变成干草原，甚至在最下端会出现沙漠。

上行树带界线，和雪线一样，在热带最高，在极地最低。从极地地区的海平面到干燥的亚热带地区的海拔4 500米处以及潮湿的热带地区海拔3 500米至4 500米处都有上行树带界线。树带界线内通常是常绿树，它们和处于上行树带界线处极端恶劣环境中生长的落叶树木相比，具有一定的优势。然而，在部分地区也有由落叶阔叶林组成的树带界线。例如，在喜马拉雅的部分地区，桦树就在树带界线上。

上行树带界线的树木开始扭曲和变形，尤其在中高纬度地区的树木，这些地区的树木往往会在山脊上长得更高，而在热带地区的树木则在山谷里长得更高;因为中高纬度地区树带界线受积雪覆盖时间和深度的影响很大。由于山谷中积雪覆盖较厚且持续时间很长，树木即便是生长在大风和贫瘠的土地里，也往往会在山脊上长得更高。在热带地区山谷里更有利于生长，因为山谷不易干涸、很少结霜，并且有更深的土壤。

目前还没有一个普遍认同的解释来说明为什么会在树带界线上出现树木停止生长这种戏剧化的现象。多种环境因素都起到作用，例如，积雪过多会让树木透不过气，雪崩和雪移能摧毁树木;长时间积雪缩短了有效生长季节的时间，树苗无法生长;另外，风速会随着海拔的升高而增加，增加树木承受的压力，很明显，正是这种风速带来的压力导致树木在高纬度地区发生变形。一些科学家提出，随着海拔的上升而不断增强的紫外线、野生山羊等动物的放养，都是导致树带界线形成的因素。或许最重要的环境因素是温度，因为如果生长季节太短并且气温太低，树芽和树苗都无法充分地成长而存活过冬季。

在林木线之上有一个称为高山苔原的地带。由于紧挨着树带界线，苔原上都是矮灌木、草本植物和牧草。随着海拔的增加，物种的数量和多样性会逐渐减少，直到出现大量空地伴着零星的苔藓和地衣这样的伏地垫状植物。有些植物甚至可以在雪线以上有利的微环境中生存，世界上海拔最高的植物是出现在喜马拉雅山上6 100百米的马卡鲁峰。在这个高度上，被阳光温暖过的岩石可以将小雪堆融化。

高山植物最突出的特点是其低矮的生长形态。这种特点使他们能够避开大风最强势的势头，并且有助于他们利用紧邻地面相对较高的温度。在这样一个低温限制生命的地区，地表提供的额外温度是至关重要的。低矮的生长形态也可以帮助植物充分利用冬季积雪所提供的保温环境。在赤道区的山脉上低矮的生长形态并不常见。

托福TPO1阅读真题原文及答案翻译相关

tpo1阅读原文 第7篇

The word "dramatic" in the passage is closest in meaning to

○gradual

○complex

○visible

○striking

Where is the lower timberline mentioned in paragraph 1 likely to be found?

○In an area that has little water

○In an area that has little sunlight

○Above a transition area

○On a mountain that has on upper

Which of the following can be inferred from paragraph 1 about both the upper and lower timberlines?

○Both are treeless

○Both mark forest

○Both are surrounded by desert

○Both suffer from a lack of

Paragraph 2: The upper timberline, like the snow line, is highest in the tropics and lowest in the Polar It ranges from sea level in the Polar Regions to 4,500 meters in the dry subtropics and 3,500-4,500 meters in the moist Timberline trees are normally evergreens, suggesting that these have some advantage over deciduous trees (those that lose their leaves) in the extreme environments of the upper There are some areas, however, where broadleaf deciduous trees form the Species of birch, for example, may occur at the timberline in parts of the

Paragraph 2 supports which of the following statements about deciduous trees?

○They cannot grow in cold

○They do not exist at the upper

○They are less likely than evergreens to survive at the upper

○They do not require as much moisture as evergreens

Paragraph 3: At the upper timberline the trees begin to become twisted and This is particularly true for trees in the middle and upper latitudes, which tend to attain greater heights on ridges, whereas in the tropics the trees reach their greater heights in the This is because middle- and upper- latitude timberlines are strongly influenced by the duration and depth of the snow As the snow is deeper and lasts longer in the valleys, trees tend to attain greater heights on the ridges, even though they are more exposed to high-velocity winds and poor, thin soils In the tropics, the valleys appear to be more favorable because they are less prone to dry out, they have less frost, and they have deeper

The word "attain" in the passage is closest in meaning to

○require

○resist

○achieve

○endure

The word "they" in the passage refers to

○valleys

○trees

○heights

○ridges

The word "prone" in the passage is closest in meaning to

○adapted

○likely

○difficult

○resistant

According to paragraph 3, which of the following is true of trees in the middle and upper latitudes?

○Tree growth is negatively affected by the snow cover in valleys

○Tree growth is greater in valleys than on

○Tree growth on ridges is not affected by high-velocity

○Tree growth lasts longer in those latitudes than it does in the

Paragraph 4：There is still no universally agreed-on explanation for why there should be such a dramatic cessation of tree growth at the upper Various environmental factors may play a Too much snow, for example, can smother trees, and avalanches and snow creep can damage or destroy Late-lying snow reduces the effective growing season to the point where seedlings cannot establish Wind velocity also increases with altitude and may cause serious stress for trees, as is made evident by the deformed shapes at high Some scientists have proposed that the presence of increasing levels of ultraviolet light with elevation may play a role, while browsing and grazing animals like the ibex may be another contributing Probably the most important environmental factor is temperature, for if the growing season is too short and temperatures are too low, tree shoots and buds cannot mature sufficiently to survive the winter

Which of the sentences below best express the essential information in the highlighted sentence in the passage? In correct choices change the meaning in important ways or leave out essential

○Because of their deformed shapes at high altitudes, trees are not likely to be seriously harmed by the strong winds typical of those

○As altitude increases, the velocity of winds increase, leading to a serious decrease in the number of trees found at high

○The deformed shapes of trees at high altitudes show that wind velocity, which increase with altitude, can cause serious hardship for

○Increased wind velocity at high altitudes deforms the shapes of trees, and this may cause serious stress for

In paragraph 4, what is the author"s main purpose in the discussion of the dramatic cessation of tree growth at the upper timberline?

○To argue that none of several environment factors that are believed to contribute to that phenomenon do in fact play a role in causing

○To argue in support of one particular explanation of that phenomenon against several competing explanations

○To explain why the primary environmental factor responsible for that phenomenon has not yet been identified

○To present several environmental factors that may contribute to a satisfactory explanation of that phenomenon

Paragraph 6: The most striking characteristic of the plants of the alpine zone is their low growth This enables them to avoid the worst rigors of high winds and permits them to make use of the higher temperatures immediately adjacent to the ground In an area where low temperatures are limiting to life, the importance of the additional heat near the surface is The low growth form can also permit the plants to take advantage of the insulation provided by a winter snow In the equatorial mountains the low growth form is

The word "prevalent" in the passage is closest in meaning to

○predictable

○widespread

○successful

○developed

According to paragraph 6, all of the following statements are true of plants in the alpine zone EXCEPT:

○Because they are low, they are less exposed to strong

○Because they are low, the winter snow cover gives them more protection from the extreme

○In the equatorial mountains, they tend to be lower than in mountains

○Their low growth form keeps them closer to the ground, where there is more heat than further

Paragraph 5: Above the tree line there is a zone that is generally called alpine █Immediately adjacent to the timberline, the tundra consists of a fairly complete cover of low-lying shrubs, herbs, and grasses, while higher up the number and diversity of species decrease until there is much bare ground with occasional mosses and lichens and some prostrate cushion █Some plants can even survive in favorable microhabitats above the snow The highest plants in the world occur at around 6,100 meters on Makalu in the █At this great height, rocks, warmed by the sun, melt small █

Look at the four squares [█] that indicate where the following sentence could be added to the

This explains how, for example, alpine cushion plants have been found growing at an altitude of 6,180

Where would the sentence best fit?

Directions: An introductory sentence for a brief summary of the passage is provided Complete the summary by selecting the THREE answer choices that express the most important ideas in the Some sentences do not belong in the summary because they express ideas that are not presented in the passage or are minor ideas in the This question is worth 2

At the timberline, whether upper or lower, there is a profound change in the growth of trees and other

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●

●

Answer choices

○Birch is one of the few species of tree that can survive in the extreme environments of the upper

○There is no agreement among scientists as to exactly why plant growth is sharply different above and below the upper

○The temperature at the upper timberline is probably more important in preventing tree growth than factors such as the amount of snowfall or the force of

○The geographical location of an upper timberline has an impact on both the types of trees found there and their physical

○High levels of ultraviolet light most likely play a greater role in determining tree growth at the upper timberline than do grazing animals such as the

○Despite being adjacent to the timberline, the alpine tundra is an area where certain kinds of low trees can endure high winds and very low temperatures

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