Do hardwoods give off more oxygen than pine trees?

Question

In my state, Weyerhauser (a company) harvests and buys pine trees... meaning tens of thousands of acres are cleared and planted in pine trees which have a quick maturation (appx. 30 years). Is the destruction of hardwoods to do this detrimental to the overall production of oxygen? Someone told me hardwoods produce over 300 times the amount of oxygen.

Answer 1

If you are looking solely at oxygen production, you need to look larger than the scale of an individual tree, and look at the whole ecosystem. Yes, each tree produces oxygen, but each year, when the trees leaves fall, and when the trees' seeds are eaten by animals, and when trees die, and the dead wood and leaves decompose, oxygen is turned back into carbon dioxide. In many mature ecosystems, there is very little net release of oxygen--oxygen is generally being released (and carbon stored) fastest in a new, growing ecosystem, such as when trees grow up in a grassy field.

There is, however, an important distinction between northern boreal forests (where most plants are evergreen), and temperate deciduous forests. In a boreal forest, the temperatures are so cold, and the leaf little (i.e. the needles) is so acidic (low nitrogen content) that it doesn't break down much. Thus, it accumulates over time, and carbon is stored. In a temperate forest, the leaf litter is rich in nitrogen, and the temperatures are warmer, so the material breaks down faster.

There is an interesting exception to this--note, I mentioned that acidity and nitrogen content is important. In a bog, there is a very low nitrogen content, and thus the leaf litter becomes very acidic. Bogs also contain plants like Sphagnum moss which contribute to this acidic environment--they thrive in it so they make the environment more acidic so other plants can't survive. In this environment, stuff doesn't break down. The layers just accumulate.

This is how fossil fuels are made. In fact, you can even take the peat out of bogs and burn it for fuel--it's very dirty, however, although people have done this in poor areas of Great Britain at various points in history.

So...if you really want to think about net oxygen production, start thinking about ecosystems as a whole. And start thinking boreal forests and bogs, and also think about reforesting deforested areas. This is where the biggest CO2 storage impact is!

Answer 2

Peachy sounds right. More vigourous growth, (although its photosynthesis instead of metabolism).

Maybe you should ask that "someone" who told you about hardwoods producing over 300 times more O2, where he got his data, or if he is just guessing without scientific measurement or proof.

Keep in mind, hardwoods are without any leaves, not producing any oxygen at all for several months, like 8 months, Sept to April inclusive, which is 2/3 of the year, bare, dormant, unproductive.

Evergreens are green all year long. Whenever the weather is mild, during mild/warm spells, they're ready and active producing oxygen. In between winter and spring, when weather turns warmer and hardwoods are still deciding to wake up, then slowly starting to bud, evergreens are already doing their job full-time, counteracting our smog, converting our carbondioxide emissions to oxygen.

Answer 3

Honestly, I don't see how. Since evergreens usually grow faster than hardwoods, that would seem to indicate that they have a higher metabolism. Hence, more food and water consumption and therefore, more cellular respiration resulting in more oxygen production. I'm not a scientist, but this seems plausible to me.

Answer 4

back in 1958 we had a forest ranger give my dad thousands of pine tree to plant and he was telling me about them and he said they,the pine tree take in oxygen and give out nitrogen. would like to find out if that true