TPO 23

The reading and the lecure are both about declining of the yellow cedar tree, which is declining for over a century. The author of the reading believes there are three causes that lead to the declining of the tree. The lecturer challenges the statements made by the author. He is of the opinion that the causes that are mentioned in the reading are adequate.
First of all, the author suggests that the decline is caused by a parasite insect called the cedar bark beetle. It is mentioned that this insect and its larvae eat the wood and have been observed to massively attack the tree. The argument is refuted by the lecturer. He says the yellow cedar tree is known for having more resistant to parasites than any other tree because the yellow cedar tree is saturated with defense chemicals. Furthermore, he argues that the beetles usually attack already damaged yellow cedar tree.
Secondly, the article posits that bears could be a culprit for the decline of the tree. The article notes that the tree has a lot of sugar content and the aggressive eating characteristics of the bear are damaging the tree. The lecturer, however, casts doubt on this by asserting that bears are not the cause of overall decline of the tree. The lecturer elaborates on this by mentioning that this tree is declining in both the mainland as well as island, which has no bear populations. Hence, bears are not the cause.
Finally, it is stated in the reading that climate change could be the reason. The author establishes that due to climate change, the roots of the tree are growing in late winter than early spring, making the tree susceptible to partial freezing. The lecturer, on the other hand, opposes that many more trees die in lower elevations than high elevations, which means cold weather is not likely the main cause. He puts forth the idea that it is true that climate change makes the roots more sensitive but not killing them.