General Question

Ltryptophan's avatar

From where does a tree accumulate its substance?

Asked by Ltryptophan (11073points) September 14th, 2010

I planted a tree when I was 5. Said tree is now over 40’. It must weigh over 1000 lbs. So where is the crater from the depletion of the soil it took to build itself up so tall? How does this work?

I suppose any plant and soil combo would suffice for an explanation, but the quantities of stuff that goes into a tree is more dramatic.

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13 Answers

ragingloli's avatar

water, carbon dioxide, sunlight, minerals extracted from the ground (that is replenished constantly by rain, dead plants and animals)

Lightlyseared's avatar

It takes carbon atoms out of the air and turns it into tree. So 1 ton of tree means there is 1 ton less carbon dioxide in the atomsphere.

Zaku's avatar

If nothing had been living there at all, but the same amount of dust and dead leaves and whatever else had fallen in the area all around its root base, there would probably be another 1000 points of matter somewhere around there, or perhaps washed downstream from there. The plant takes nutrients and builds with them, which otherwise would have been washed downstream, been converted by some other plants, animals or insects or microbes, or would have accumulated there.

marinelife's avatar

It takes energy to grow from sunlight (photosynthesis).

It does not take mass out of the soil, it takes minerals.

Ltryptophan's avatar

But, just like my daily vitamin, isn’t that what the soil is…isn’t some amount of 1 lb. of soil in fact minerals, and stuff the tree used to build?

If ¼ lb. of each full lb. of soil is stuff that could be used in the structure of the tree, shouldn’t some divot, albeit small show up?

LuckyGuy's avatar

The tree is pulling carbon dioxide out of the air, mixing it with water and a touch of minerals and is making cellulose, hemi cellulose and lignin. The minerals account for a small percentage of the mass of the tree. Based upon ash content data it is 1–3% by mass.
If you want to see the hole, yank the tree out of the ground with a backhoe.

Ltryptophan's avatar

@worriedguy I had a discussion with my grandfather…he suggested the same approach for finding the hole. But I don’t think that accounts for the amount of stuff above ground.

CMaz's avatar

How old are you now?

gondwanalon's avatar

Over the many years of the tree’s life, in utilizes tons of CO2 from the air and water from the ground.

majorrich's avatar

I’ve been told that a tree in 90% air, but every time I hit a golf ball trying to pass through, I get lucky and hit the 10%.

Beta_Orionis's avatar

The Tree is made mostly of Carbon, Hydrogen, and Oxygen, which do not come from the soil. You could say that the root volume has replaced the soil used for minerals. Imagine Tree absorbs minerals, roots grow longer. That’s not a perfect exchange, but it does account for the lack of discernable missing soil. Also, as it rains, as the wind blows, the soil is redistributed and settles, so the “holes” can be refilled.

CyanoticWasp's avatar

Assume that the tree does weigh 1000 pounds. Let’s assume 2000 pounds, in fact.

A lot of that mass did come from the soil. Don’t forget that the tree has a huge root ball, maybe even more massive than what you see above ground. However, the root mass is not as dense as the soil mass. (Easily proven, since “roots” for most of the trees we’re familiar with will float on water, and the soil will not.)

Ergo, the roots below the surface of the soil have replaced a generally equal volume of more dense material: soil.

But as others have also pointed out very ably, the tree is also composed of carbon, which mostly came from the air, as well as hydrogen and oxygen which came from water. The plant uses the energy it receives from the sun to recombine the basic elements: primarily carbon, hydrogen, oxygen, to form wood, bark, leaves, sugars and sap… a tree.

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