Reading Comprehension

Defoliating insects damage trees by eating leaves or needles, removing the photosynthetic tissue critical for plant maintenance and growth. A significant loss of leaves or needles results in growth loss, increased susceptibility to attack by other insects and pathogens, and sometimes tree mortality.

The impact of defoliation on individual trees is dependent on a variety of factors. Tree species vary in their tolerance to defoliation. In most cases, hardwood species can sustain repeated defoliation over several years because they store large food supplies and can re-foliate in the same year. The timing of the defoliation relative to seasonal growth benchmarks is also important. For example, late season defoliation of hardwoods has a lesser impact than does late season defoliation of conifers; even a single late season defoliation of pines often results in tree mortality. As a general rule, trees that are healthy and growing vigorously will survive defoliation better than stressed trees.

Historically, the two most destructive defoliators in the Southwestern Region were the western spruce budworm and the Douglas-fir tussock moth. Both of these defoliators can cause severe growth loss, top-kill, increased susceptibility to bark beetles, and cause outright tree mortality. More recently, three other defoliators have been causing heavy defoliation in higher elevation forests. Since the early 1990s, the exotic spruce aphid and a native looper, Nepytia janetae, have caused high levels of mortality in the spruce-fir forest type in the White Mountains and Pinaleño Mountains of Arizona. More recently, a New Mexico fir looper outbreak began in 2002 in the Sacramento Mountains of southeastern New Mexico, causing elevated levels of fir mortality.

7
Based on the passage, which of the following would probably be LEAST susceptible to mortality from defoliation?



A
A growing fir tree in the White Mountains of Arizona
B
A healthy hardwood tree in a low elevation forest
C
A healthy pine tree late in the growth season
D
A hardwood tree still recovering from a previous defoliation
E
A pine tree early in the growth season that is free of bark beetles

D
In most cases, hardwood species can sustain repeated defoliation over several years because they store large food supplies and can re-foliate in the same year.

My explanation:

A- incorrect - Mountains make trees more susceptible

B- Incorrect - Low elevation forest - out of scope

C- Incorrect -late in the growth season -more susceptible

D-Incorrect -healthy and growing vigorously will survive defoliation better than stressed trees--this tree is affected hence not healthy

E-Correct - A pine tree early in the growth season that is free of bark beetles--Growing and not affected by beetles (defoliators can cause severe growth loss,increased susceptibility to bark beetles)

Pls post the OA with explanation

Thanks
karthik

A, C and E are out in the first selection.

Of B and D, I will go for B.

because of 2 reasons

1. In most cases, hardwood species can sustain repeated defoliation over several years because they store large food supplies and can re-foliate in the same year.

2. As a general rule, trees that are healthy and growing vigorously will survive defoliation better than stressed trees.

Reason 1 applies to both B and D. As per Reason 2, D is more stressed and so B.

Can someone post the correct answer

D seems to be good for me
since
for B
More recently, three other defoliators have been causing heavy defoliation in higher elevation forests.
It is just an recent examples which may be one out of many.
and x is not white doesnt mean x is black
it effects higher elevation doesnt mean
if effects or doesnot affect low level forest

Others
It is reversed cause and effect.
If there is no effect doesnt mean it mitigates cause.
for eg no bark doesnt mean no cause...
rather
cause ...leads to no barks

thanks

Confused b/w B & D. Low elevation forest is nowhere mentioned in passage. So i think that D should be the answer. Experts please confirm what to do in such cases.

IMO E

What is OA?

At the end of 2nd Paragraph-
"As a general rule, trees that are healthy and growing vigorously will survive defoliation better than stressed trees. "

A- A growing fir tree in the White Mountains of Arizona (3rd Para says - Since 1990 - X and Y has caused high mortality in White moutain - INCORRECT)
B- A healthy hardwood tree in a low elevation forest ( Low elevation - not mentioned in passage)
C- A healthy pine tree late in the growth season ( Healthy, not in growth season - INCORRECT)
D- A hardwood tree still recovering from a previous defoliation ( Stressed - INCORRECT)
E- A pine tree early in the growth season that is free of bark beetles ( GROWING, Least suspectible to Bark Beetle) --> CORRECT.

Yup i agree but "hardwood species can sustain repeated defoliation over several years because they store large food supplies and can re-foliate in the same year" and "even a single late season defoliation of pines often results in tree mortality." are also mentioned so i though it should be D

would be better to place official answer on spoiler .

IMO A

IMO E

E +1
OA please???

Hi Guys,

the correct answer to this one is B. a bit tricky, read these lines in the last para.

"More recently, three other defoliators have been causing heavy defoliation in higher elevation forests. "

and u people already must have figured out that hardwood is better than pine.