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From an advertisement for turf / rolled sod by a German company:

250 m² Rollrasen produzieren etwa so viel Sauerstoff wie 10.000 m² Kiefernwald oder etwa so viel, wie eine vierköpfige Familie zum atmen braucht. 

translation:

250 m² rolled sod produces approximately as much oxygen as 10000 m² pine forest or as much as a family of 4 needs to breathe

Does rolled sod / turf really release significantly (factor 40?) more oxygen than a pine forest?

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    [For the unit-challenged] 10000 square meters is about 2.5 acres. – GEdgar Apr 20 at 13:32
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    It doesn't actually seem that implausible to me. Plants generate oxygen by growing (photosynthesis means over-simplified that carbon-dioxide gets turned into oxygen and carbon, and that carbon becomes more plant). And grass grows pretty quick under the right conditions. But the problem is that you are going to cut the grass sooner or later. And the cut grass in then burnt or composted, which uses up oxygen and releases carbon. – Philipp Apr 20 at 14:26
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    @GEdgar, the unit is the same in both numbers, thus it can safely be - and actually is in the last paragraph of the question - cancelled out. - In the official German unit for area it is "2 Fußballplätze", though. (1 football field - or soccer field, for the sports-challenged - is about 5.000 m² ;) ) – I'm with Monica Apr 20 at 17:39
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    10000 sq m is exactly one hectare. – Weather Vane Apr 20 at 18:51
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    Important context: whatever the relative oxygen emissions are doesn't really matter, because the broader implication (that sod is good because oxygen production is good) is moot. At least half the oxygen emissions of the world come from plankton, and the ocean more generally. Pine forests and sod gardens are comparatively irrelevant – Alexander - Reinstate Monica Apr 20 at 19:15
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As the top answer to this related question states, plants in general are oxygen neutral. In other words, whatever oxygen is emitted today will be emitted as CO2 later. So what really matters from a climate perspective is CO2 storage, not oxygen emission.

That said, short-term oxygen emission is apparently difficult to measure, but it is largely a function of leaf surface area. This extension site from the University of California states:

Assignment levels of oxygen emission are not precise and different methods can give different results. That said, it is well documented that oxygen release is proportional to the overall leaf mass, also known technically as Leaf Area Index.

There is general agreement that:

  • Pines are at the bottom of the list in terms of oxygen release because they have a low Leaf Area Index.

I can find lots of sod companies promoting the oxygen producing properties of their product, but no independent research supporting their claims. It is possible that immediate oxygen emission by sod is higher than pine forest, but as far as I can tell, the 10.000 m² is just a made-up and meaningless figure.

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    The important thing to take away here is, the whole "how much does this plant sequester vs. this plant" is a strawman argument. The answer is always "not enough to make a difference". Plant biomass is at best a buffer, not a deposit or counterweight to fossil CO2 emission. – DevSolar Apr 20 at 16:50
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    @DevSolar, well, fossil carbon comes from such a buffer, too, albeit one that has been cut off from the atmosphere for millions of years. – I'm with Monica Apr 20 at 17:43
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    "Damaged peatlands are a major source of greenhouse gas emissions, annually releasing almost 6% of global anthropogenic CO2 emissions." (source). Call that a buffer or a deposit, whatever that means... it's small but not insignificant. – Brian Z Apr 20 at 18:05
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    @I'mwithMonica Which means that the fossil carbon will overwhelm the buffer, which had evolved to buffer the current natural emissions, not those reintroduced from those millions of years ago. As I said, strawman. You can introduce acid into a pH buffer as well, with no ill effects at first. Until that buffer is saturated... – DevSolar Apr 20 at 18:13
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    This question is asking about oxygen production not carbon capture. Why do you spend your first paragraph answering a question that wasnt asked and is unrelated to what was asked? – Matt Apr 20 at 20:47

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