TPO 23

In this set of materials, both the reading passage and the lecturer discuss possible reasons for the declining population of a yellow cedar tree that was life in North American. Although the passage provides three theories for declining cedar trees, the speaker refutes all of the arguments described in this reporter.

To start off, the passage points out that some insects such as beetle had been attacked by the yellow cedar trees, and they killed these trees. The lecturer, in contrast, rejects this by claiming that the healthy cedar trees were more resistant than other trees to attacking insects. He explains that the yellow cedar trees produce a chemical liquid compound that is poisoning beetles. So, if these trees are healthy, the beetle cannot kill them. So, the cedar trees would be damaged before attacking beetles such as becoming ill or died. Therefore, the beetle only attacks the unhealthy cedar trees.

Going through the next approach, the passage points out that the cedar trees produce a sweet liquid that attracted the brown bears, and the brown bears would be weekend brown trees. However, the professor argues that the overall population of the yellow cedar trees died. Such trees were lived on the mainland and the Island. But, the brown trees are not living on the mainland which trees become existent. So the brown trees cannot be declining them.

Finally, although the passage says that climate change is an important reason for declining of cedar trees because their roots so sensitive to the cold weather the speaker disagrees by mentioning that many of the yellow cedar trees were died at lower elevate which the weather is warm compare to the higher elevation and cooler weather. Thus this declining pattern counters the hypotheses of climate change role in yellow cedars' population decrease.