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 to 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 insect is 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 passage that mentions three hypotheses for the decline in yellow cedars: cedar bark beetle, brown bears and climate change. However, the lecture casts doubt on the passage by claiming non of these hypotheses is adequate to explain this phenomenon.
First, the passage claims that the yellow cedar decline may be caused by insect parasites, specifically the cedar bark beetle. Notwithstanding, the lecture counters the passage by pointing out that healthy yellow cedars are more resistant to insects. Though bark beetles can harm cedars, they can only harm sick cedars. Since healthy cedars produce poisonous that can kill insects, insects are unlikely the reason for the decline of cedars.
Secondly, the passage states that brown bears could be the reason for the decline. Because bears sometimes claw at the cedars in order to eat the tree bark, and their aggressive feeding habits may critically weaken enough trees. Yet the lecture denies the passage by arguing that the decline happened all across North America, including continent and islands. But brown bears do not appear in island, so brown bears may not be the cause for the decline.
Finally, the passage argues that gradual changes of climate may be to blame. Since the fine surface roots now start growing in the late winter rather than in the early spring, they are likely to suffer damage from partial freezing on cold winter nights. Nevertheless, the passage refutes the passage by arguing that more trees died in warmer areas than in cold areas. Thus, climate change is inadequate to explain the decline of cedar populations.
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Transition Words or Phrases used:
but, finally, first, however, if, may, nevertheless, second, secondly, so, thus
Attributes: Values AverageValues Percentages(Values/AverageValues)% => Comments
Performance on Part of Speech:
To be verbs : 9.0 10.4613686534 86% => OK
Auxiliary verbs: 8.0 5.04856512141 158% => OK
Conjunction : 5.0 7.30242825607 68% => OK
Relative clauses : 8.0 12.0772626932 66% => More relative clauses wanted.
Pronoun: 13.0 22.412803532 58% => OK
Preposition: 30.0 30.3222958057 99% => OK
Nominalization: 0.0 5.01324503311 0% => More nominalizations (nouns with a suffix like: tion ment ence ance) wanted.
Performance on vocabulary words:
No of characters: 1346.0 1373.03311258 98% => OK
No of words: 261.0 270.72406181 96% => OK
Chars per words: 5.15708812261 5.08290768461 101% => OK
Fourth root words length: 4.0193898071 4.04702891845 99% => OK
Word Length SD: 2.37304287401 2.5805825403 92% => OK
Unique words: 145.0 145.348785872 100% => OK
Unique words percentage: 0.555555555556 0.540411800872 103% => OK
syllable_count: 408.6 419.366225166 97% => OK
avg_syllables_per_word: 1.6 1.55342163355 103% => OK
A sentence (or a clause, phrase) starts by:
Pronoun: 2.0 3.25607064018 61% => OK
Article: 7.0 8.23620309051 85% => OK
Subordination: 4.0 1.25165562914 320% => Less adverbial clause wanted.
Conjunction: 3.0 1.51434878587 198% => OK
Preposition: 2.0 2.5761589404 78% => OK
Performance on sentences:
How many sentences: 14.0 13.0662251656 107% => OK
Sentence length: 18.0 21.2450331126 85% => The Avg. Sentence Length is relatively short.
Sentence length SD: 29.040524114 49.2860985944 59% => The essay contains lots of sentences with the similar length. More sentence varieties wanted.
Chars per sentence: 96.1428571429 110.228320801 87% => OK
Words per sentence: 18.6428571429 21.698381199 86% => OK
Discourse Markers: 5.64285714286 7.06452816374 80% => OK
Paragraphs: 4.0 4.09492273731 98% => OK
Language errors: 0.0 4.19205298013 0% => 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: 4.0 4.27373068433 94% => OK
What are sentences with positive/Negative/neutral sentiment?
Coherence and Cohesion:
Essay topic to essay body coherence: 0.191265545784 0.272083759551 70% => OK
Sentence topic coherence: 0.0727308248493 0.0996497079465 73% => OK
Sentence topic coherence SD: 0.0493445005852 0.0662205650399 75% => OK
Paragraph topic coherence: 0.12255948551 0.162205337803 76% => OK
Paragraph topic coherence SD: 0.0282425851821 0.0443174109184 64% => OK
Essay readability:
automated_readability_index: 12.2 13.3589403974 91% => Automated_readability_index is low.
flesch_reading_ease: 53.21 53.8541721854 99% => OK
smog_index: 3.1 5.55761589404 56% => Smog_index is low.
flesch_kincaid_grade: 10.3 11.0289183223 93% => OK
coleman_liau_index: 12.65 12.2367328918 103% => OK
dale_chall_readability_score: 8.22 8.42419426049 98% => OK
difficult_words: 61.0 63.6247240618 96% => OK
linsear_write_formula: 8.5 10.7273730684 79% => OK
gunning_fog: 9.2 10.498013245 88% => OK
text_standard: 9.0 11.2008830022 80% => OK
What are above readability scores?
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Rates: 75.0 out of 100
Scores by essay e-grader: 22.5 Out of 30
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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.