4 ms·

how did new trees grow when the ground was covered in piles of dead trees?

by asah 6y ago

Pfhreak 6y ago
Trees are capable of growing in and on other trees. Also, most of the tree comes from air, not the ground.
- FredPret 6y ago
  Do you happen to know what percentage of trees are from CO2 and what from the soil? I’ve always wondered how much carbon is captured in, say, a book, or a dresser
  - tonyarkles 6y ago
    I don’t know the exact number, but came across a wild thought experiment a while ago that drove it home. Look at a big tree. There’s 3 things that could have gone into making it: water, air, and earth. If you look at the ground around it, there’s no hole where the tree grew. Sure, there’s the root system, but there’s nowhere near enough dirt missing to have made both the root system and the 50’ above-ground portion of the tree. That only leaves air and water.
    - FredPret 6y ago
      That’s a good one. Though it’s possible the soil is less dense around the roots due to mineral absorption. But I suppose the majority of the mass must come from water and carbon in the air.
      - Pfhreak 6y ago
        Feynman on this exact question: https://m.youtube.com/watch?v=ifk6iuLQk28&feature=emb_title https://m.youtube.com/watch?v=ifk6iuLQk28&feature=emb_title
    - sitkack 6y ago
      I have seen 50+ foot tall trees growing directly out of ancient lava flows, nearly zero soil. From a cursory search, it looks like about 88% of the dry mass of a tree comes from the atmosphere (CO2 and H2O).
  - neurostimulant 6y ago
    Dry wood is about 50% carbon, 41% oxygen, 6% hydrogen, and 3% trace minerals, so it's probably safe to say that over 50% of it comes from CO2, and the rest from water and soil.
    - mahogany 6y ago
      Is there not carbon in the soil? Edit: I misread what you said. I think you are claiming that because there is so much carbon and oxygen, probably more than half comes from CO2. But there is both carbon and oxygen (well really, air) in soil. Although apparently the concentration of CO2 in the soil's air is much higher than it is in the normal atmosphere, so it's possible your statement is correct. (Plus looking at dry wood composition is a bit odd when it's generally less than 15% moisture content - that leaves out a lot of water that's present in a living tree.)
      - Pfhreak 6y ago
        Dry mass is typically used because it's consistent. Trees fluctuate over the year, being drier in some seasons than other. But they'll have the same dry mass. Trees are mostly C6 H10 O5, coming from CO2 and H20. Based on atomic weight about 70% of the mass of the dry wood comes from CO2. Fresh wood will have extra water content, taken from the soil (though that water came from the air too). There is carbon in the soil, but most plants don't take carbon up from their roots meaningfully. Nitrogen, phosphorus, potassium, and other trace minerals. Decomposers like fungi, bacteria, and insects will eat the carbon in the soil and release CO2.
FredPret 6y ago
I’m no ancient tree expert, but I imagine they’d eventually be buried under layers of new soil, washed away, or be swept along with geological movements
- gumby 6y ago
  What do you think “new soil” is made of? The original trees evolved in a soil with different composition from the soil we have today (which today includes the consequences of decomposition of... trees). I mean sure some of that could happen due to a bit of wind, so you’re not at all wrong. But the volume of thick loamy topsoil isn’t mostly tiny rock grains (sand) but a living amalgam of bacteria, fungi, plant matter, plantae, animal detritus (faeces but also cast off skin or carapaces...). Part of the problem with modern farming is that parts of the economic process treat the soil as an inert matrix (just as road bike manufacturers justifiably (in their case) don’t spend time thinking of the road as part of the bike system).

how did new trees grow when the ground was covered in piles of dead trees?

by asah 6y ago

how did new trees grow when the ground was covered in piles of dead trees?

Pfhreak 6y ago

Trees are capable of growing in and on other trees. Also, most of the tree comes from air, not the ground.

FredPret 6y ago
Do you happen to know what percentage of trees are from CO2 and what from the soil? I’ve always wondered how much carbon is captured in, say, a book, or a dresser
- tonyarkles 6y ago
  I don’t know the exact number, but came across a wild thought experiment a while ago that drove it home. Look at a big tree. There’s 3 things that could have gone into making it: water, air, and earth. If you look at the ground around it, there’s no hole where the tree grew. Sure, there’s the root system, but there’s nowhere near enough dirt missing to have made both the root system and the 50’ above-ground portion of the tree. That only leaves air and water.
  - FredPret 6y ago
    That’s a good one. Though it’s possible the soil is less dense around the roots due to mineral absorption. But I suppose the majority of the mass must come from water and carbon in the air.
    - Pfhreak 6y ago
      Feynman on this exact question: https://m.youtube.com/watch?v=ifk6iuLQk28&feature=emb_title https://m.youtube.com/watch?v=ifk6iuLQk28&feature=emb_title
  - sitkack 6y ago
    I have seen 50+ foot tall trees growing directly out of ancient lava flows, nearly zero soil. From a cursory search, it looks like about 88% of the dry mass of a tree comes from the atmosphere (CO2 and H2O).
- neurostimulant 6y ago
  Dry wood is about 50% carbon, 41% oxygen, 6% hydrogen, and 3% trace minerals, so it's probably safe to say that over 50% of it comes from CO2, and the rest from water and soil.
  - mahogany 6y ago
    Is there not carbon in the soil? Edit: I misread what you said. I think you are claiming that because there is so much carbon and oxygen, probably more than half comes from CO2. But there is both carbon and oxygen (well really, air) in soil. Although apparently the concentration of CO2 in the soil's air is much higher than it is in the normal atmosphere, so it's possible your statement is correct. (Plus looking at dry wood composition is a bit odd when it's generally less than 15% moisture content - that leaves out a lot of water that's present in a living tree.)
    - Pfhreak 6y ago
      Dry mass is typically used because it's consistent. Trees fluctuate over the year, being drier in some seasons than other. But they'll have the same dry mass. Trees are mostly C6 H10 O5, coming from CO2 and H20. Based on atomic weight about 70% of the mass of the dry wood comes from CO2. Fresh wood will have extra water content, taken from the soil (though that water came from the air too). There is carbon in the soil, but most plants don't take carbon up from their roots meaningfully. Nitrogen, phosphorus, potassium, and other trace minerals. Decomposers like fungi, bacteria, and insects will eat the carbon in the soil and release CO2.

FredPret 6y ago

I’m no ancient tree expert, but I imagine they’d eventually be buried under layers of new soil, washed away, or be swept along with geological movements

gumby 6y ago
What do you think “new soil” is made of? The original trees evolved in a soil with different composition from the soil we have today (which today includes the consequences of decomposition of... trees). I mean sure some of that could happen due to a bit of wind, so you’re not at all wrong. But the volume of thick loamy topsoil isn’t mostly tiny rock grains (sand) but a living amalgam of bacteria, fungi, plant matter, plantae, animal detritus (faeces but also cast off skin or carapaces...). Part of the problem with modern farming is that parts of the economic process treat the soil as an inert matrix (just as road bike manufacturers justifiably (in their case) don’t spend time thinking of the road as part of the bike system).