Populations of the yellow cedar, a species of tree that is common in northwestern North America, have been steadily declining for more than a century now, since about 1880. Scientists have advanced several hypotheses explain this decline.
One hypothesis is that the yellow cedar decline may be caused by insect parasites, specifically the cedar bark beetle. This beetle is known to attack cedar trees; the beetle larvae eat the wood. There have been recorded instances of sustained beetle attacks overwhelming and killing yellow cedars, so this insectis a good candidate for the cause of the tree’s decline.
A second hypothesis attributes the decline to brown bears. Bears sometimes claw at the cedars in order to eat the tree bark, which has a high sugar content. In fact, the cedar bark can contain as much sugar as the wild berries that are a staple of the bears’ diet. Although the bears’ clawing is unlikely to destroy trees by itself, their aggressive feeding habits may critically weaken enough trees to be responsible for the decline.
The third hypothesis states that gradual changes of climate may be to blame. Over the last hundred years, the patterns of seasonal as well as day-to-day temperatures have changed in northwestern North America. These changes have affected the root systems of the yellow cedar trees: the fine surface roots now start growing in the late winter rather than in the early spring. The change in the timing of root growth may have significant consequences. Growing roots are sensitive and are therefore likely to suffer damage from partial freezing on cold winter nights. This frozen root damage may be capable of undermining the health of the whole tree, eventually killing it.
The reading claims that scientist have proposed several reasons which can explain why the yellow cedar has been declining. However, the lecturer finds all the ideas dubious and provide some evidence to refute them all.
First, the reading argues that insect parasites can be one reason. There are recorded instances of sustained beetle attacks which causes killing the yellow cedars. On the contrary, the speaker brings up the idea that yellow cedar is so resistant to insects among other trees. The leaves of this tree have a chemical substance which is poisonous for beetle. So beetle cannot be cause of their decline. Beetle just can attack those trees which are already sick and dying.
Furthermore, the reading passage asserts that brown bears can be another reason since their eating habits are aggressive and can cause damage to these cedar trees when they are eating the tree bark. Conversely, the professor underlines the fact that cedar trees can be found in North America and their population is declining. There is no brown bear in this area and this animal cannot be the reason of this decline, since the population decline occurs with or without bears.
Finally, the author holds the view that climate change is another reason of the decline. Climate change can affect the root system of the yellow cedar trees. Roots are sensitive and when they freeze, they harm the tree and kill it. On the other hand, the lecturer dismisses this issue due to the fact that the weather is cold in higher elevation and it is warm in lower elevation. If the climate change was the reason of the decline, we would see more decline in higher elevation while this is vice versa in reality. More decline happens in lower elevation where it is warm.
| Post date | Users | Rates | Link to Content |
|---|---|---|---|
| 2020-01-24 | supergirl20 | 40 | view |
| 2020-01-11 | Raziya | 80 | view |
| 2020-01-05 | S M Naimul Mamun | 70 | view |
| 2019-11-27 | shingwa | 80 | view |
| 2019-11-21 | omarsamiiir | 73 | view |
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Grammar and spelling errors:
Line 3, column 375, Rule ID: BE_CAUSE[1]
Message: Did you mean 'because'?
Suggestion: because
... poisonous for beetle. So beetle cannot be cause of their decline. Beetle just can attac...
^^^^^^^^
Transition Words or Phrases used:
conversely, finally, first, furthermore, however, if, so, while, on the contrary, on the other hand
Attributes: Values AverageValues Percentages(Values/AverageValues)% => Comments
Performance on Part of Speech:
To be verbs : 21.0 10.4613686534 201% => Less to be verbs wanted.
Auxiliary verbs: 10.0 5.04856512141 198% => OK
Conjunction : 9.0 7.30242825607 123% => OK
Relative clauses : 14.0 12.0772626932 116% => OK
Pronoun: 26.0 22.412803532 116% => OK
Preposition: 26.0 30.3222958057 86% => OK
Nominalization: 8.0 5.01324503311 160% => OK
Performance on vocabulary words:
No of characters: 1456.0 1373.03311258 106% => OK
No of words: 298.0 270.72406181 110% => OK
Chars per words: 4.88590604027 5.08290768461 96% => OK
Fourth root words length: 4.15483772266 4.04702891845 103% => OK
Word Length SD: 2.19537987752 2.5805825403 85% => OK
Unique words: 159.0 145.348785872 109% => OK
Unique words percentage: 0.53355704698 0.540411800872 99% => OK
syllable_count: 450.0 419.366225166 107% => OK
avg_syllables_per_word: 1.5 1.55342163355 97% => OK
A sentence (or a clause, phrase) starts by:
Pronoun: 2.0 3.25607064018 61% => OK
Article: 9.0 8.23620309051 109% => OK
Subordination: 2.0 1.25165562914 160% => OK
Conjunction: 0.0 1.51434878587 0% => OK
Preposition: 3.0 2.5761589404 116% => OK
Performance on sentences:
How many sentences: 17.0 13.0662251656 130% => OK
Sentence length: 17.0 21.2450331126 80% => The Avg. Sentence Length is relatively short.
Sentence length SD: 39.3744335929 49.2860985944 80% => OK
Chars per sentence: 85.6470588235 110.228320801 78% => OK
Words per sentence: 17.5294117647 21.698381199 81% => OK
Discourse Markers: 5.82352941176 7.06452816374 82% => OK
Paragraphs: 4.0 4.09492273731 98% => OK
Language errors: 1.0 4.19205298013 24% => OK
Sentences with positive sentiment : 1.0 4.33554083885 23% => More positive sentences wanted.
Sentences with negative sentiment : 9.0 4.45695364238 202% => Less negative sentences wanted.
Sentences with neutral sentiment: 7.0 4.27373068433 164% => OK
What are sentences with positive/Negative/neutral sentiment?
Coherence and Cohesion:
Essay topic to essay body coherence: 0.224695397746 0.272083759551 83% => OK
Sentence topic coherence: 0.0702345956991 0.0996497079465 70% => OK
Sentence topic coherence SD: 0.0615598319917 0.0662205650399 93% => OK
Paragraph topic coherence: 0.132417458 0.162205337803 82% => OK
Paragraph topic coherence SD: 0.0273917290195 0.0443174109184 62% => OK
Essay readability:
automated_readability_index: 10.4 13.3589403974 78% => Automated_readability_index is low.
flesch_reading_ease: 62.68 53.8541721854 116% => OK
smog_index: 3.1 5.55761589404 56% => Smog_index is low.
flesch_kincaid_grade: 8.7 11.0289183223 79% => OK
coleman_liau_index: 10.79 12.2367328918 88% => OK
dale_chall_readability_score: 7.71 8.42419426049 92% => OK
difficult_words: 61.0 63.6247240618 96% => OK
linsear_write_formula: 6.0 10.7273730684 56% => Linsear_write_formula is low.
gunning_fog: 8.8 10.498013245 84% => OK
text_standard: 9.0 11.2008830022 80% => OK
What are above readability scores?
---------------------
Rates: 75.0 out of 100
Scores by essay e-grader: 22.5 Out of 30
---------------------
Note: the e-grader does NOT examine the meaning of words and ideas. VIP users will receive further evaluations by advanced module of e-grader and human graders.