how trees get high

8/8/2019 How Trees Get High

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How Trees Get HighHow Trees Get High

By: Adam SummersBy: Adam Summers

Recapped By: Apoorv KakarRecapped By: Apoorv Kakar


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Question:Question:

Adam SummersAdam Summers As we stood dwarfed byAs we stood dwarfed by

the grove of towering trees, I pondered andthe grove of towering trees, I pondered and

thought: how do trees grow so tall, and what, ifthought: how do trees grow so tall, and what, ifanything, keeps them growing talleranything, keeps them growing taller

Summary: What really causes trees toSummary: What really causes trees to

grow/What allows trees to keep growing?grow/What allows trees to keep growing?


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Quick Review of Tree PartsQuick Review of Tree Parts

RootsRoots: The part of a plant that is usually: The part of a plant that is usually

underground, and whose primary functionsunderground, and whose primary functions

are anchorage and the absorption of waterare anchorage and the absorption of water

and dissolved mineral salts.and dissolved mineral salts.

XylemXylem: Transport tissue found in vascular: Transport tissue found in vascular

plants, whose main function is to conductplants, whose main function is to conductwater and dissolved mineral nutrients fromwater and dissolved mineral nutrients from

the roots to other parts of the plant.the roots to other parts of the plant.

TrunkTrunk: the main structural member of a: the main structural member of a

tree that supports the branches and istree that supports the branches and is

supported by and directly attached to thesupported by and directly attached to the

roots.roots.

LeafLeaf: external plant organ specialized for: external plant organ specialized for

photosynthesis.photosynthesis.


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Water, Water,WaterWater, Water,Water

Water is the single most crucial part for the life of a treeWater is the single most crucial part for the life of a tree

Water does not ordinarily run uphillWater does not ordinarily run uphill

Aristotle knew that it was impossible to pull water higher than approximatly 30Aristotle knew that it was impossible to pull water higher than approximatly 30

feetfeet

Atmospheric pressure can only support column of water about 30ft tall.Atmospheric pressure can only support column of water about 30ft tall. Thanks to the most important property of water, capillary action, water is able toThanks to the most important property of water, capillary action, water is able to

climbclimb!!


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Capillary Action/Route ContinuedCapillary Action/Route Continued

Trees rely on evaporation to raise an unbroken column of water from the soil up to its leaves,Trees rely on evaporation to raise an unbroken column of water from the soil up to its leaves,where some of it is used in photosynthesis.where some of it is used in photosynthesis.

The water diffuses from the soil through root hairs and into xylem tubes running upwardThe water diffuses from the soil through root hairs and into xylem tubes running upwardwithin the sapwood. The electrostatic attraction of water molecules for one another canwithin the sapwood. The electrostatic attraction of water molecules for one another cansustain enough tension to support a continuous, cohesive column of water as high as 420 feet.sustain enough tension to support a continuous, cohesive column of water as high as 420 feet.

Much of the water at the top of the column evaporates into empty space within a leaf, thenMuch of the water at the top of the column evaporates into empty space within a leaf, then

diffuses into the air through pores on the underside of each leaf.diffuses into the air through pores on the underside of each leaf. The evaporation opens up space near the top of the column for more water to move upwardThe evaporation opens up space near the top of the column for more water to move upward

through capillary action. That motion, transmitted through the unbroken column of water,through capillary action. That motion, transmitted through the unbroken column of water,ultimately draws more water from the ground into the root hairs.ultimately draws more water from the ground into the root hairs.


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What determines the strength of theWhat determines the strength of the

water transport?water transport? Tension!Tension!

The tension on the molecules at any point in the column must support the weight of all the waterThe tension on the molecules at any point in the column must support the weight of all the water

below thembelow them

For every thirty feet of tree height, the tension increases roughly 15 lbs per square inch.For every thirty feet of tree height, the tension increases roughly 15 lbs per square inch.

The environment also plays a key role in the tension of the water column.The environment also plays a key role in the tension of the water column.


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Little explanation of pressure andLittle explanation of pressure and

heightheight


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Some further explanationSome further explanation

Experiment Time!Experiment Time!

George Koch, a plant physiologist at Northern Arizona University, ran two experimentsGeorge Koch, a plant physiologist at Northern Arizona University, ran two experiments

A) Gauged pressure in the xylem as well and the rate of photosynthesis as they climbed the five tallest trees inA) Gauged pressure in the xylem as well and the rate of photosynthesis as they climbed the five tallest trees in

the worldthe world

B) Performed laboratory tests altering the environment the plant tissue was inB) Performed laboratory tests altering the environment the plant tissue was in

He was able to conclude two thingsHe was able to conclude two things

A) tension in the water column is highest, and the rate of photosynthesis the lowest, nearest the top of the trees.A) tension in the water column is highest, and the rate of photosynthesis the lowest, nearest the top of the trees.

B) tension on the water column in the dry sunlit air at noon, is right at the limit of its (water) cohesive strength.B) tension on the water column in the dry sunlit air at noon, is right at the limit of its (water) cohesive strength.

Due to increased rate of photosynthesisDue to increased rate of photosynthesis causes more pullcauses more pull


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In ConclusionIn Conclusion

Water is what lets trees grow tall, and allowsWater is what lets trees grow tall, and allows

them to keep growing, to an extent of course.them to keep growing, to an extent of course.

Waters properties (capillary action, tension,Waters properties (capillary action, tension,

and cohesiveness) prove to be a great set ofand cohesiveness) prove to be a great set of

tactics to supply a tree with its needs and allowtactics to supply a tree with its needs and allow

them to grow to their limits.them to grow to their limits.

WATER IS THE METHOD BEHIND THEWATER IS THE METHOD BEHIND THE

MADNESS!MADNESS!


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THEENDTHEEND

how trees get high

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