Integrated essay on the yellow cidar trees

The lecture and the passage are arguing on hypothesizes that claim the declination of the yellow cedar trees in northwestern North America. The passage postulates various hypothesis to support the reasons for reductions in the population of the yellow cedar trees. The lecture, however, posits that explanation are not enough to explain the reduction of the population.

First, the passage states that the cedar bark beetles’ larvae eat the wood of the tree, so they are responsible for declination. On the other hand, the lecture casts doubt and claims that the healthy cedar trees are resistant to those insects. Their leaves and barks contain chemicals that are poisonous to the insects. So insect are not the cause of reduction of the trees. In this way, the passage contradicts the passage’s first hypothesis.

According to second hypothesis postulated in the passage, the brown bears are the one of the causes of the demise of the population. In contrast, the lecturer says that some bears have impact on the cedar tree, but overall declination is not possible due to the bears. Additionally, he says that cedars are present on northwestern mainland and on islands of North America, whereas the bears are not present on islands at all. And declination on island is still continued. Thus, the lecture disclaims the second hypothesis as well.

The third hypothesis in the passage claims that gradual change in the climate leads to the reduction in the cedar trees’ population. On the contrary, the lecture dismisses this claim by stating that the trees at lower elevations have warm climate compared to those of at higher elevations. And the climate must be drier at low elevations. However, it is not the case in cedar trees location. So their root system is not sensitive to cold climate and not killing the tree. Therefore, the explanation made in the passage is inappropriate in the lecturer’s point of view.