Forests and the carbon cycle

No, cellulose is a 'standard' sugar polymer and enzymes that fit it for decomposition purposes are various and widespread. In fact it is perhaps an oddity that mammals can't digest it. Although some groups like ruminants make their stomach into a multichambered bioprocessor where bacteria get it done. In the environment of some chambers, other bacteria turn acetate (which happens to be hanging around) into methane. People have heard of those farts (if I may so say). Humans are set up differently, and such emissions are dominated by hydrogen.

Wood is cellulose plus lignin, and the latter is the enzymatic problem. It is a chaotic train record of (usually) three types of monomers, about which you probably don't want to know more. But there are some points of interest. The monomers, inside the plant, are made from particular amino acids, that get their 'aminos' removed and recycled. It's no great feat to estimate that that nitrogen recycling by plants is comparable in size to the nitrogen that plants use for photosynthesis. But we don't hear very much about that 'quiet' nitrogen cycle. Lignolytic enzymes produce free radicals and other similar highly oxidizing molecules that may 'bump into' lignin and cleave it. Otherwise, they bump into something else. It seems not very clever, but it works. Otherwise wood in forests would just stack up, years, millenia, and this would be a very different planet. That was something like Freeman Dyson's idea.

All the enzymes above, and others, get released into surrounding environment by (many ) decomposers, who if they are lucky, get to feast on the resulting monomers. Something not entirely unlike your aluminum oxide protection happens in clay minerals, and lots of enzymes 'go to waste' thereby.

The ERL paper is a follow-on to one from the same group (more or less) who found that most of the trees in Amazonia are of less than 200 species. So you can get away with not learning names of all 3500 species (that is approximate, and for sure there are a few rare ones still unknown, unnamed).

What, OCO-2 defunded? Say it ain't so.

We can get into the free lunch thing some other time. It is fascinating to people with tastes as odd as mine.

 

I was just recently in one of my favorite forests, Ailao Mountain. It had a big snowstorm in January and (my estimate) about a quarter of the canopy was knocked down. Quite a haircut. This means

A whole lot of new dead wood for decomposers, as well as leaves.
All my previous field experiments were smashed flat, some of which merit getting dug out.
Other peoples' field experiments, same thing.
What had been trails through the forest are now debris piles, and much machete work to restore access
In about a year, there is going to be bamboo EVERYWHERE, which is not good for walking through either
No pandas live there (now), but they'd not suffer for snacks

The understory trees are in pretty good shape. maybe they will 'bolt for the sky'. I don't know that such a thing has been studied.

In 2008, roughly through Guizhou/Hunan/Jiangxi* there was a major ice storm that made similar damage over a much larger area. I did not manage to get the local folk very interested in studying the results. Some have been done though.

What ecologists do study a lot is the year-in, year-out production and decomposition cycles. We suppose that is important. Yet it may be that these rare, high-impact events are what really structures the forests. Maybe barking up the wrong trees

*Less anyone think I have become expert In Geography of China, there is a map on the wall behind me...

 

...white rot fungi comes to mind...trying to recall why I guess it is wood fungi that has found use in remediation of certain waste sites

 

Yay! the old separation between fungal modes lives on! wjtracy, I hope you have seen white rot and brown rot out there in real life. The contrast is stark and for those given to hyperbole, amazing.

WR removes mostly lignin and leaves behind mostly cellulose. BR is the opposite. So, each group creates an ideal food source for the other. However, that other fails to move in, for years or decades. This is the best traditional demonstration of fungal fighting, rarely recognized as such.

The bioremediation also mentioned is a big deal. That lignin can be removed and cellulose 'uncovered' for bioenergy is a big deal. More basically, the harnessing of microbial aggression for human medicine began with penicillin. From one of the nastiest actinobacteria that you will even meet.

 

Most commercial fungal spores are so you can grow your own edible mushrooms in wood or bags of straw. The hallucinogenic ones sold are presumably illegal in most jurisdictions.

Fungus mycelia (hyphae, threads) are not generally snacked on as far as I know. Very hard to know if what you are looking at is an edible or toxic species. By the time they pop up as mushrooms, it is much easier. But still people die from misidentified mushrooms. Some kinds will make you exceedingly uncomfortable prior to the final coda.

This is not to say that the 'boring 3' often sold in US are the only good eating. This here province of China is famous for edible fungus diversity. Some are very very good, others not so to my taste.

 

That might extend to most of the vertebrates, but in our case, I say it is just because we are lazy. Why do the work when we can get something else to do it for us?

 

Similarly, I was reflecting on the tension it must of caused between Fred Flintstone and Barney Rubble and their seemingly conflicting support of Cocoa Pebbles and Fruity Pebbles respectively.

Great minds think alike.

 

A new paper in “Science”


DOI: 10.1126/science.aaa1668


Suggests that savannahs and shrublands cause much of the annual variability in carbon sequestration on land. Secondarily, that tropical forests provide much of the annual average uptake. It is good that somebody is working these things out.


The models used for this analysis differ from global climate models in that they can be (and are) tested at a variety of sites. Plant production “just sits there” and is amenable to measurement. Not that they are perfect; decomposition is still treated primitively in my opinion.


There have been many experiments manipulating temperature, water inputs and other things in forests across the globe, but not so many in savannahs. I hope we see more of those in the future.

 

Most European forests, except the least accessible, had old growth removed like 1000 years ago. Agriculture, make fire for the various metal ages, build flammable houses.

The few that remain (Poland, Romania, thereabouts) are relatively small but quite justly famous. Recently even those have been getting 'snipped' and news media are actually noticing.

Actually, talking about that Biome (temperate forests) remaining old growth is pretty darn rare. More can actually still be found in Boreal and Tropics. Most of they are quite a hike, and that's the point. Road access is very closely linked to forest pressure.