Burning stuff and green issues

geordie_joe

CLAPTON wrote: »

In deed so , if we allocate infinite space for trees to grow and spread then of course that's right.
But if the amount of space allocated to trees is constrained then the process I described is carbon neutral.

You are right there, it would be in that case. But trees have a way of growing in the most unlikely places. They just need enough ground an to be left alone. Any bit of countryside will do, it doesn't have to be a forest.

After the great storm of 87 the forestry commission set about replacing millions of trees that had been blown down. They couldn't afford to replace them all so had to leave some forests to their own devices.

20 years later they announced that the forests they had left alone had done far better than the ones where they had replanted trees. I can't remember the exact words, but what they said was something along the lines of "After 20 years all we have learned is that when it comes to growing trees nature does it far better than the human experts".

All the money they spent replanting the trees had been wasted, because if they had done nothing even more trees would have grown simply by letting nature take it's course.

Anyway, I'm not against people burning wood, or planting tree, if they are planting trees because they want a particular type of tree to grow in that place.

But I am against large corporations trying to tell is things are "carbon neutral" when really they just want to sell more log burners, or chain saws, or lumberjack jackets etc. And as for carbon offsetting, it's the biggest money making scam on the planet.

Ben84

geordie_joe wrote: »

Yes but you have to cause co2 to be taken out of the atmosphere, just as by burning wood you cause carbon to be put into the atmosphere.

Just saying that if another tree is grown then it is carbon neutral doesn't work. Where does the tree come from?

If you mean that a seed drops from another tree and grows then that seed was going to grow anyway and you have not "caused" it to grow.

If you mean a tree is bought and planted then this doesn't work either as that tree also came from a seen and would have grown anyway. Just because someone picked it up and put it in a pot for a few years then transplanted it back into the forest doesn't mean they created the tree or caused any co2 to be taken out of the atmosphere.

Cutting down trees and claiming it is carbon neutral because another tree will grow is just claiming credit for a tree that was going to grow whether or not you cut the other one down.

You might as well just look in the obituary column and find someone who died today and offset all your carbon against the carbon they are not going to cause to be released.

I believe the reasoning is that trees are recently grown. The carbon released from burning the wood was collected as the tree grew over the past 10, 20 or however many years. It shouldn't be able to increase carbon dioxide in the atmosphere above recent levels as the process is collecting carbon that was already free in the atmosphere in a convenient form and allowing you to release the stored energy. Nature would do this anyway when the tree eventually died, it would rot and release just as much carbon as burning it will.

Fossil fuels are different, their carbon was collected and removed from the atmosphere millions of years ago. Burning them frees carbon that naturally wouldn't have gone back in to the atmosphere, which can (and has) elevated free carbon in the atmosphere above recent levels such as those from 50 years ago.

The carbon is the same, but it's coming from a totally different part of the carbon cycle, and this means it affects the carbon cycle in a very different way.

CLAPTON

I think it's important to get the science right.

There were, in fact plenty of scientists saying just 'leave the forests and they will regenerate themselves' in 1987...

Just as forests do after forest fires.

And there were plenty of warning about biofuels too for that matter

However there are other factors in the final decisions some very sensible and many of course rather unworthy.

And 'coppicing' a stable mature wood for fuel can indeed be carbon neutral although there may be many other issues that make it unsuitable for solving the energy problems.

Ben84

Paper and wood products are seemingly renewable, but there are some important issues.

Trees are a crop, and as we've recently seen with biofuels, using agricultural land to make fuel on a large scale can seriously unsettle food prices. Inconvenient for us here, and a massive disaster for people who live in significant poverty. Those who spend 80% or more of their income on food.

Trees also, like any crop over time deplete the soil. Natural forests grow and thrive because when the plants die they decay and return the nutrients they extracted during their life to the local environment - something that doesn't happen when we remove large quantities of wood repeatedly. The same land will not continue to produce crops of any type indefinitely without us adding nutrients to it, which makes the process unsustainable as we're having to bring in resources from outside, which inevitably means depleting a resource somewhere else.

There are environmental and economical limitations on how many trees we can grow and use for human purposes, but I believe we haven't yet seen them as we do not consume trees on a big enough scale to see them yet. Trees and biofuels in general are being viewed much like oil was decades ago, as an unlimited resource. We can say "grow another tree" just as blithely as people must have once said "drill for some more oil". One day we may even use the term "peak trees", if we consume enough and deplete enough land to the point where it will not sustain further tree growing.

However, at least for now these problems seem far enough away to ignore, or in most cases not even think about.

CLAPTON

Well, we can do the maths now to work out 'peak trees' and its not a realistic solution to our energy needs.

N9eav

Ben84 wrote: »

Paper and wood products are seemingly renewable, but there are some important issues.



Trees also, like any crop over time deplete the soil. Natural forests grow and thrive because when the plants die they decay and return the nutrients they extracted during their life to the local environment - something that doesn't happen when we remove large quantities of wood repeatedly. The same land will not continue to produce crops of any type indefinitely without us adding nutrients to it, which makes the process unsustainable as we're having to bring in resources from outside, which inevitably means depleting a resource somewhere else.

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I worked in West Africa for a number of years and quite a bit of land was taken over to grow teak wood trees. Apparently the land was useless after 5 years when they felled the trees for the crop.

Recently around here they cut down about 50 trees or more all 'non native' species. They planted native oaks and beech etc instead. But although I have several tons of wood. I quite liked the 50 foot scaniavian pines as opposed to the 2 foot oak saplings

mech_2

I think you're all over-labouring the point here really. If it's free wood (old pallets, offcuts, etc) it's not exactly deforesting the country. It was already waste.

I've got a pile of waste wood in my garage and no wood burner to burn it in. Most of it came from my garden, but I didn't fell any trees to get it. I just lopped off branches that were crowding, or rubbing, or too low and hitting me in the face.

Generally I wouldn't worry about burning wood. Tree cover in the UK has more than doubled in the last 100 years or so. There can't really be "peak trees" anyway, as they're a renewable resource. "Peak oil" or "peak uranium" means supply can no longer keep up with demand, but if wood didn't keep up with demand we could just plant more trees. Growing saplings absorb more carbon than mature trees anyway.

I wouldn't worry too much about depleting the soil either. When you burn wood, you're mostly burning sugar polymers (made with sunlight, carbon dioxide and water) and the wood ash (potash) can go back onto the land or into a compost heap. It's alkaline, containing minerals such as potassium, magnesium, phosphorus and calcium.

Wood is so low in nitrogen that when it rots it pulls nitrogen out of the soil.