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wolfgang

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wolfgang Mentor

wolfgang

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Nine years ago,when Mike was 6 years old, he stood against a tree and drew a black line on the tree trunk with a permenant marker ( suppose the line will stay forever!)indicating his height at that time.

Yesterday, he stood again at the same place as he did before and drew a red line on the tree trunk.

1- let the growth rate of Mike to be constant,( 2.55 inches )/ year.

2- let the growth rate of the tree to be constant also ( 18.21 inches )/ year.

Which line will be above the other?the black or the red?why?

How many inches will be the distance between the two lines?

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sparkyboy6 Enthusiast

sparkyboy6

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Nine years ago,when Mike was 6 years old, he stood against a tree and drew a black line on the tree trunk with a permenant marker ( suppose the line will stay forever!)indicating his height at that time.

Yesterday, he stood again at the same place as he did before and drew a red line on the tree trunk.

1- let the growth rate of Mike to be constant,( 2.55 inches )/ year.

2- let the growth rate of the tree to be constant also ( 18.21 inches )/ year.

Which line will be above the other?the black or the red?why?

How many inches will be the distance between the two lines?

Very confusing :blink:
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Was Mike's growth always constant? Meaning at 6 years old was he 15.3" tall? That is pretty short for a 6 year-old. We also need to know how tall the tree was when first marked. If it was a few inches taller than Mike, as the tree grows the black like will be up in the highest branches. If it is an old tree, the mark would move very little since the 18.21 inches would be proportional to the entire tree. On a 30ft tree the black line would not move very much over 9 years.

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Black line will be above the red because the tree is growing faster than him. When he puts the red line on the tree (yesterday) that will be 5 years and for this we'll use 364 days because today would be 365. So the black line will be 109.2101 minus 15.29301 from the red line = 93.9171 inches apart

That is if im thinking about this correctly

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Brandonb Grand Master

Brandonb

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2 questions...

1st- How does a tree grow? I'm about 99% sure that it doesn't grow strictly from the bottom up... Does it grow from the top up, or is the growth evenly disbursed throughout(as I would suspect)?

2nd- How tall is the tree?

If the tree grows so that the growth is evenly disbursed throughout its entirety, then the height of the tree must be known in order to disbursed that known growth.

In addition, we need to know Mike's original height. Because we must determine how much of that disbursed tree growth applies to the portion of the tree that was equal or less than his original height. And thus only then will be able to determine the difference between the old and the new marks.

Edited by Brandonb
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The red line is higher, because the tree grows mostly from the top, not the bottom up. So even though it grows at a faster rate, the black line didn't get much higher.

Nine years ago,when Mike was 6 years old, he stood against a tree and drew a black line on the tree trunk with a permenant marker ( suppose the line will stay forever!)indicating his height at that time.

Yesterday, he stood again at the same place as he did before and drew a red line on the tree trunk.

1- let the growth rate of Mike to be constant,( 2.55 inches )/ year.

2- let the growth rate of the tree to be constant also ( 18.21 inches )/ year.

Which line will be above the other?the black or the red?why?

How many inches will be the distance between the two lines?

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Nine years ago,when Mike was 6 years old, he stood against a tree and drew a black line on the tree trunk with a permenant marker ( suppose the line will stay forever!)indicating his height at that time.

Yesterday, he stood again at the same place as he did before and drew a red line on the tree trunk.

1- let the growth rate of Mike to be constant,( 2.55 inches )/ year.

2- let the growth rate of the tree to be constant also ( 18.21 inches )/ year.

Which line will be above the other?the black or the red?why?

How many inches will be the distance between the two lines?

If the tree was more than 7,14 (18,21/2,55) times higher than Mike 9 years ago, the red line is above the black line.

If the height of Mike was B and the height of the tree was A, the distance between the red and the black lines is:

22,95 - 163,89 * B / A.

If the number is positive, the red line is above the black.

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wolfgang Mentor

wolfgang

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Was Mike's growth always constant? Meaning at 6 years old was he 15.3" tall? That is pretty short for a 6 year-old. We also need to know how tall the tree was when first marked. If it was a few inches taller than Mike, as the tree grows the black like will be up in the highest branches. If it is an old tree, the mark would move very little since the 18.21 inches would be proportional to the entire tree. On a 30ft tree the black line would not move very much over 9 years.

No...he was 41 inches when he was 6 years old..

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wolfgang Mentor

wolfgang

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Black line will be above the red because the tree is growing faster than him. When he puts the red line on the tree (yesterday) that will be 5 years and for this we'll use 364 days because today would be 365. So the black line will be 109.2101 minus 15.29301 from the red line = 93.9171 inches apart

That is if im thinking about this correctly

:wacko:

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wolfgang Mentor

wolfgang

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2 questions...

1st- How does a tree grow? I'm about 99% sure that it doesn't grow strictly from the bottom up... Does it grow from the top up, or is the growth evenly disbursed throughout(as I would suspect)?

2nd- How tall is the tree?

If the tree grows so that the growth is evenly disbursed throughout its entirety, then the height of the tree must be known in order to disbursed that known growth.

In addition, we need to know Mike's original height. Because we must determine how much of that disbursed tree growth applies to the portion of the tree that was equal or less than his original height. And thus only then will be able to determine the difference between the old and the new marks.

As you wish my friend...let us say Mike was 41 inches and the tree was 143 inches,nine years ago...although you don`t need them!

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araver Veteran

araver

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I guessed that was going to be the case. But can someone explain the contents of the spoiler in my previous post, please?

here suggests that a tree only grows from its tips. If that's true, does that mean that a tree with its first branch (say) 6 ft off the ground grows as a single stem for 6ft? Or am I missing something?

]

It is true that if a tree is very small/young - say 1 feet about the ground and you cut it somewhere at the ground level, you will see that cut rising as the tree evolves.

Happened to me with a very young walnut when I was a kid and almost cut it through before my grandpa was able to stop me and teach me the difference between trees and grass. The scar of the cut was at the ground level. 20 some years later, the scar of the cut is slightly above my head.

I'm pretty sure this is much less obvious for a birch for example.

After a while, the converse applies in some (if not all) species of trees. The external bark seems to stop rising and instead, the growth concentrates on the far tips (making them grow in length - elongation) and on the inside of the trunk up to the first branch (secondary growth making the trunk grow in lateral size=girth).

Since the two types of growth are different, what's relevant to your question and the problem is the elongation part which can indeed be ignored for the trunk if a tree already reaches a predetermined height.

And to answer your other question, even if a tree grows its first branch at a point, then it still continues to rise itself for a while until it stops. I think that the stopping occurs when the tree's girth growth creates a sufficient shielding of (non-living) bark and it is somewhat independent to the appearance of a branch.

So for a tree with its first branch (say) 6 ft off the ground it's most likely that it grew as a single stem for less than 6ft - let's say x feet, where x depends on the species (the speed in which it grows its bark) and for a species with slow secondary growth, it could be much less that 6 ft.

I'm not sure if it's the answer you were looking for.

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I think that

Set kid height nine years ago as x (black line)

Set tree height nine years ago as y (Also Black line)

x=y

Set kid height now as a (Red line)

Set tree height now as b (Also Black line)

Back in 2001 x had distance x

Back in 2001 y had distance y

Now in 2010 a have distance x + 9 * 2.55 = x + 22.95

Now in 2010 b have distance y + 9*18.21 = y + 163. 29

becouse x = y

a = x + 22.95

b = x + 163. 29

(DO GET CONFUSED)

*What we just found is that the tree have advanced more than the kid in nine years

Meaning that the black line have advanced also more than the boy(Red line) in 9 years.

Black line > Red line

*Not sure about the second one

i suppose that if we remove 22.95 from 163.29 we get the diffrence bettowen red and black line

22.95-163.29 = 140,34

Edited by Tsopi
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fabpig Veteran

fabpig

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It is true that if a tree is very small/young - say 1 feet about the ground and you cut it somewhere at the ground level, you will see that cut rising as the tree evolves.

Happened to me with a very young walnut when I was a kid and almost cut it through before my grandpa was able to stop me and teach me the difference between trees and grass. The scar of the cut was at the ground level. 20 some years later, the scar of the cut is slightly above my head.

I'm pretty sure this is much less obvious for a birch for example.

After a while, the converse applies in some (if not all) species of trees. The external bark seems to stop rising and instead, the growth concentrates on the far tips (making them grow in length - elongation) and on the inside of the trunk up to the first branch (secondary growth making the trunk grow in lateral size=girth).

Since the two types of growth are different, what's relevant to your question and the problem is the elongation part which can indeed be ignored for the trunk if a tree already reaches a predetermined height.

And to answer your other question, even if a tree grows its first branch at a point, then it still continues to rise itself for a while until it stops. I think that the stopping occurs when the tree's girth growth creates a sufficient shielding of (non-living) bark and it is somewhat independent to the appearance of a branch.

So for a tree with its first branch (say) 6 ft off the ground it's most likely that it grew as a single stem for less than 6ft - let's say x feet, where x depends on the species (the speed in which it grows its bark) and for a species with slow secondary growth, it could be much less that 6 ft.

I'm not sure if it's the answer you were looking for.

That's exactly the answer I was looking for. Thanks araver. :thumbsup:

The people who wrote the article should use you as a consultant. :D

Edited by fabpig
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dark_magician_92 Rising Star

dark_magician_92

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Nine years ago,when Mike was 6 years old, he stood against a tree and drew a black line on the tree trunk with a permenant marker ( suppose the line will stay forever!)indicating his height at that time.

Yesterday, he stood again at the same place as he did before and drew a red line on the tree trunk.

1- let the growth rate of Mike to be constant,( 2.55 inches )/ year.

2- let the growth rate of the tree to be constant also ( 18.21 inches )/ year.

Which line will be above the other?the black or the red?why?

How many inches will be the distance between the two lines?

black will be above by (18.21-2.55)*9 inches if both r increasing at constant rate and the tree increases from roots/base

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