Naked Science Forum
Life Sciences => The Environment => Topic started by: peppercorn on 22/06/2012 16:36:42
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I was thinking as I was motoring along one of our beloved tributaries the other day, there must be a lot of work involved in managing the land around major roads. I would think there's many more man-hours spent on controlling the banks of trees used for screening the highways and byways of the land per acre than say a 'natural' wood or forest. Primarily the contractors (I assume it's all farmed out to private companies) must ensure that they have done everything in their power to stop trees or branches falling onto the roadway, hard-shoulder or pavement.
Based on this fact, I then wondered if anyone had thought to get something back from the high level of maintenance by managing the trees along a more coppice-like structure - ie. Rather than constantly check and selectively cut-back slow growing hardwood trees could the areas be planted out with more softwoods, whilst focusing more on harvesting the wood (for biomass or many other uses) on a regular, systematic rotation.
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Of course, Oregon has many softwood forests, firs and pines. They actually define a corridor along many of the mountain highways that is to remain uncut, and thus it looks like one is driving through the woods.
The clearcutting is thus kept away from the main roads.
I presume the corridor of trees actually has a benefit of stabilizing some of the soil along the roadways too.
I'm not sure about the level of maintenance beyond taking a mower to trim down brush that encroaches on the roadway. There is some windfall every year or two after major storms, but trees encroaching on the road are often cleaned up within a few hours. Landslides, of course, can take longer.
I live near a Bonneville main power line. They keep a 100' wide swath of land free of trees along the power line, far greater than what is done along roadways.
Power companies will also cut trees out from around smaller power lines.
Hog Fuel used to be common for power generation, but the usage has been declining in recent years due to lower mill production, and more competition with landscaping. I presume that one of the problems is that Hog Fuel is expensive to chip and transport out of the woods. I would think that with all the modern innovations though, that there would be more work on equipment designed to strip the bark and separate paper chips from hog chips that would otherwise be burnt in slash piles. And, also some kind of mowing and vacuuming hog fuel from roadside brush mowing.
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Having a large proportion of sticks, bark, leaves & grass, etc from maintaining a tree bank might make it difficult to 'densify' the resultant biomass into any useful (and economically transportable) material. I suppose if these wastes could be separated and ploughed back into the earth through composting then there might be the economics for transporting the woody portion somewhere.
A woodgas powered chipper would be a green addition to the side of the road.... er, perhaps [:-\]
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A woodgas powered chipper would be a green addition to the side of the road.... er, perhaps [:-\]
Or, pretty black addition.
I would wonder if a boiler and steam engine would be cleaner.
I suppose there are two types of chippers. One is like a big lawn mower, mowing down the brush in place. That would be the hardest to recover its trimmings.
The other is one where individual branches are fed into a chipper, usually for trees and brush that have been cut up. I've often seen small chip trucks pulling those. Presumably the chips get recycled somewhere, most likely for landscaping, although they could be collected and burnt by some of the remaining factories that rely on wood for power.
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A woodgas powered chipper would be a green addition to the side of the road.... er, perhaps [:-\]
Or, pretty black addition.
I would wonder if a boiler and steam engine would be cleaner.
Quite! That's what the 'perhaps' was for!
However, well designed woodgas generators can make good, clean producer gas that would not cause smoke.
...individual branches are fed into a chipper, usually for trees and brush that have been cut up. I've often seen small chip trucks pulling those. Presumably the chips get recycled somewhere, most likely for landscaping, although they could be collected and burnt by some of the remaining factories that rely on wood for power.
That sounds the type of thing, yes.
'Roadside' processing sounds like yet another use for Torrefaction:
Torrefaction ('cooked' wood @~300C, resulting <70% mass, >90% BTUs of wet timber) could be a means to minimise transport and storage cost.
Plus torrefaction results in a product that needs less energy to grind and pelletize. It is hydrophobic, so can be stored in the open, and the heat degradation, mainly of the wood's hemicellulose, gives it an uniform structure that makes burning or making activated-carbon more controllable and scalable.
The process of torrefaction requires very little additional energy, as the lighter fractions from the wood's heating can be collected and burnt to sustain the temperature in the retort.