Both the author of the reading and the lecturer discuss the reasons of declining yellow cedars which began happening since about 1880. The author gives three reasons to explain the reduction of this species whereas the professor finds the reasons unconvincing and claims that there is still no specific explanation for such a phenomenon.
First off, the reading contributes the decline of yellow cedar to the insect parasites and specially the beetle. The fact that beetle larvae eat the wood is used as a support to this hypothesis. The lecturer, on the other hand, states that the healthy Cedar can resist the attack of insects because of containing chemicals which could completely destroy the beetle. The explanations to existence of beetle on destroyed cedars could be the fact that insects would attack unhealthy trees and they are not the main cause of reduction.
According to the passage, brown bears could be responsible for decline. It attributes the situation to the bears clawing habits for using the tree bark as food and mentions the aggressive feeding habits of bears. The speaker, on the contrary, refutes the effect of bear feeding in declining tree species due to the fact that there are no bears existing in the north-western coast where is a common place for Cedars and reduction happens there too.
Lastly the author asserts that the reduction could be caused by gradual changes of climate. The professor disagrees with this claim. Further he explains about the regular growing locations of this type of tree which could be lower elevation which is warm or could be the higher elevation which is cold and the tree continues living in both places so the change of temperature would not affect the growth of trees.
Both the author of the reading and the lecturer discuss the reasons of declining yellow
cedars
which began happening since about 1880. The author gives three reasons to
explain
the reduction of this species whereas the professor finds the reasons unconvincing and claims that there is
still
no specific explanation for such a phenomenon.
First
off, the reading contributes the decline of yellow
cedar
to the insect parasites and
specially
the
beetle
. The fact that
beetle
larvae eat the wood is
used
as a support to this hypothesis. The lecturer,
on the other hand
, states that the healthy
Cedar
can resist the attack of insects
because
of containing chemicals which could completely
destroy
the
beetle
.
The
explanations to existence of
beetle
on
destroyed
cedars
could be the fact that insects would attack unhealthy
trees and
they are not the main cause of reduction.
According to the passage, brown
bears
could be responsible for decline. It attributes the situation to the
bears
clawing habits for using the
tree
bark as food and mentions the aggressive feeding habits of
bears
. The speaker,
on the contrary
, refutes the effect of
bear
feeding in declining
tree
species due to the fact that there are no
bears
existing in the north-western coast where is a common place for
Cedars
and reduction happens there too.
Lastly
the author asserts that the reduction could
be caused
by gradual
changes
of climate. The professor disagrees with this claim.
Further
he
explains
about the regular growing locations of this type of
tree
which could be
lower
elevation which is warm or could be the higher elevation which is
cold
and the
tree
continues living in both places
so
the
change
of temperature would not affect the growth of
trees
.