#13 - Mature white pines intercept almost all the sunlight

[Administrator]

Complete Question Explanation

Must be True. The correct answer choice is (A)

The stimulus consists of premises, but drives toward a fill-in-the-blank conclusion. You must infer the main point of the argument.

The premises establish that mature white pines obstruct sunlight well enough that such pines cannot regenerate in their own shade, and you need to decide what is likely in a stand of white pines in a dense forest.

You are supposed to pick up on the theme of sunlight-obstruction, and realize that as a stand of white pines becomes thicker, it becomes less likely that new white pines will grow. That would suggest that a dense stand of white pines consists of trees of fairly similar ages.

Answer choice (A): This is the correct answer choice. At the very least, within the stand the pines should not differ drastically in age. According to the stimulus, younger white pines would not survive if they had to grow under the cover of older white pines, so you would expect that a close grouping of white pines consists of trees of fairly similar ages.

Answer choice (B): The area would not have to be cleared of all trees, just enough trees that the white pine saplings could get enough light to grow. White pines cannot regenerate in their own shade, but might be able to regenerate in a lesser amount of shade.

Answer choice (C): The stimulus suggests that older white pines block the sunlight to seedlings, but there is no reason to assume that older white pines would deprive each other of sunlight enough that some of the older trees would die.

Answer choice (D): Since it is quite possible that the obstruction of sunlight makes it impossible for any seedling to succeed in a stand of white pines, it does not follow that other species of trees would colonize and replace the stand of white pines. This choice is unsupported, somewhat contrary, and incorrect.

Answer choice (E): The stimulus does not establish that white pines grow at a fairly invariable rate. Furthermore, the stimulus tends to suggest that the trees are all of very similar ages if they are to survive together, which tends not to support the idea that the height differences should be attributed only to age.

[desmail]

Hello,

In the stimulus, when the author says that "white pines cannot regenerate in their own shade" does that mean that an individual tree can't regenerate from its OWN individual shade or are we talking about other trees' shade?

Or does it mean any kind of shade, whether its own or from other trees?

Thanks!

[Steve Stein]

Thanks for your question. When the author says that they are so tall they can't regenerate in their own shade, that means that their shade is so thick that no light passes all the way through to the forest floor. Thus, they would also not be able to regenerate in any other similarly thick shade.

I hope that's helpful--let me know--thanks!

~Steve

[desmail]

Thanks!

[Bigfoot]

Hello,

I know answer choice A is correct, and I agree that based on the stimulus the trees must be of a similar age, but based on the stimulus I think that the age difference between them must be LESS than the time it takes a white pine to grow to full maturity, not at all more. This is because if other pines had reached maturity then they would have begun to intercept the sunlight and thus make regeneration impossible. Based on the information in the stimulus, how can it be true that the age difference is that which it requires for the trees to grow to maturity? Furthermore, how MUST it be true?

Is it simply because the other answer choices are notably mistaken and this answer choice is the only one which deals with a modest age gap? I chose B because it included a lack of mature trees, and therefore for much of the same reason that A is apparently correct. I understand now that the forest did not have to be cleared and that therefore B is incorrect, and from B on I did not consider contenders. If I had considered this, A would have been the only choice left, but it still doesn't seem to conclude the argument logically to me.

I appreciate your insight!

[Adam Tyson]

Hey Bigfoot, good to see you here! Usually you're so hard to find!

Would you believe you've answered your own question? If you're correct that the age difference must be less than the length of time it takes a tree to grow to maturity, then it must also be true that the difference cannot be much more than that! It's like saying I'm 5'9" tall, so I must not be much taller than 6'.

Now I'm not sure you're right in you assumption, because a new tree might grow just beyond the shady area under a mature tree and be much younger than the first tree, but that's neither here nor there. Take another look at your own analysis again and you'll see you have all the proof you need for answer A.

Forget "common" sense and the way normal people talk. This is the LSAT, a step towards becoming a lawyer! There's nothing common or normal about it! Just logic, logic, logic.

Now don't stay in hiding so long, will you? People just want a selfie with you!

[andriana.caban]

Answer choice (A): This is the correct answer choice. At the very least, within the stand the pines should not differ drastically in age. According to the stimulus, younger white pines would not survive if they had to grow under the cover of older white pines, so you would expect that a close grouping of white pines consists of trees of fairly similar ages.

I thought (A) was incorrect because the author doesn't discuss the time a white pine matures. Although I identified the inference that these trees must be relatively close in age, I eliminated (A) due to the maturity aspect.

I choose (B) because I figured that the land in which white pines were on had to be cleared in order for the dense white pine forest to grow. If other white pines existed, how could they all have grown to similar height + length.

This is so frustrating - I thought I had gotten this question correct and now I'm really confused as to why my answer was incorrect and (A) was because the author doesn't mention length of maturity at all. Please help!

[James Finch]

Hi Andriana,

This is a Most Strongly Supported question, so we need to make the most likely inference we can. Here, because older white maples take all the light, younger trees end up unable to grown and die off. So if all the trees are already mature, they'll take all the light and no new trees will be able to grow, meaning all the trees will likely be around the same age--if they weren't, the ones that matured first would steal all the light from the younger ones and end up killing them.

Hope this clears things up!

[vbkehs]

Hello! I chose C for this question: "competition among the trees in the stand for sunlight will soon result in some trees' dying and the stand thus becoming thinner." I interpreted "some trees' dying" as the younger trees that are deprived of sunlight. If A is true, wouldn't it also be true that other trees have died off because of the older ones that stand? Confused where I went wrong here.

Thanks in advance!

[Adam Tyson]

Which trees will die, vbkehs? We know that new trees won't grow, but why should any of the ones that are already there, which are all mature and soaking up sunlight at the top, die? There's nothing in the stimulus about some trees blocking sunlight so that other trees die. It's that they block the sunlight and prevent new trees from growing at all! For all we know, all the mature trees will just chill with each other and stick around for hundreds of years.