trees

[kopking8]

Would it be accurate to say that trees are made from air and water?

[squarebear]

Nope. What makes you say that?

[kopking8]

Came across the question somewhere, didn't think it would be correct but I thought I'll ask, why would anyone bar me ask that question..

[squarebear]

Trees were made from wood when I was at school unless it's trick question.

[gen2]

kopking8, That is not a daft question. It is almost accurate in the following sense.

Plant growth progresses primarily through photosynthesis where carbondioxide (from the air) combines with water to form carbohydrates which are the main constituents of plants.

So what else is required? Well firstly there is Nitrogen. This also could be said to come from the air as there are nitrogen fixing bacteria that can make atmospheric nitrogen available to some plants.

But that is about as far as you can go in support of your original premise. Plant life would be impossible without the additional uptake of several mineral elements. Amongst them you would need phosphorus, potassium, magnesium and many more which vary from plant to plant.

[squarebear]

Plus the seed of the tree to start with.

[beso]

There is actually a surprising amount of mineral in trees including silica which can be up to a few percent. The ash left behind when they burn is mostly silica.

[kopking8]

Thank you.

[theprof]

beso, the amount of silica in tree ash is hardly measurable. It's often not in the range of parts per thousand let alone the "few percent" you assert.

The white ash left behind from burnt trees is mainly composed of Calcium no matter what climate the trees are located in. Ash from trees that have grown in sandy soil, do indeed show a slightly higher amount of silica in the ash due to deposition of silica in bark, but the increase is negligible.

Have a look at the following link for further information:

http://forestry.oxfordjournals.org/cgi/reprint /79/5/563.pdf