TPO 23 Integrate Essay

In this set of materials the article posits that North America is facing with the decreases of yellow cedar trees in populations, and provides three possible reasons for this trouble. However, the lecturer raises questions on the ideas and presents some evidence to refute them all.

First, the author of the reading passage states that insects' parasites, such as bark beetles, are one of the main cause of this problem, due to attacking the cedar trees. On the contrary, the professor cast doubt on this point by saying that yellow cedar trees are much more resistant than other trees against insects, while other trees still can be seen in this area. According to the professor, cedar trees have poison which can kill the insects; therefore, insects can't make serious problem for these trees.

The following explanation which is uttered in the article is that bears' clawing could be another reason for vanishing the cedar trees because these trees contain abundant sugar. In contrast, the lecturer explains that bears has nothing to do with the disappearing the cedar trees. He mentions that there are no bears on the islands, meanwhile cedar trees are vanishing on the islands too. If the bears was the cause of this trouble, trees on the islands could be exist till now.

Finally, the reading passage asserts that climate changing, which resulted to colder weather, directly affected the cedar trees and killed them. Conversely, the speaker indicates that this comment is unlikely to be true. The professor implies that observation revealed that cedar trees in the warmer and lower elevations are decreased more than areas with colder and higher elevations. Thus, climate variation can't be responsible for these phenomena.