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Speakout: Clear-cutting for runoff 'delusional'
http://www.insidedenver.com/drmn/opi...581500,00.html
Speakout: Clear-cutting for runoff 'delusional' By Harv Teitelbaum, Special to the News December 2, 2002 The notion of clear-cutting huge tracks of forest to increase runoff for water containments is not only self-serving industry pandering, but delusional. While supporters hold up one carefully chosen test where some limited success was realized, the practical, real world effects would be quite different. Rather than being net depleters of moisture, trees and forests help increase moisture by "fixing" it in ground and surface sources. Trees use some of the moisture from snow in their upper stories while, aided by gravity, sun and wind, they permit most to find its way to the surface. This surface moisture is then shaded from excessive evaporation by the trees, allowing it to percolate downward, maintaining soil moisture balance, feeding root systems, reducing erosion, and recharging ground sources. Evapotranspiration from trees helps maintain the water cycle and local climate. On the other hand, open landscapes of snow are like open water reservoirs, i.e., massive moisture evaporators. Not only would the result of massive clear-cutting be a net loss of ground and surface moisture due to increased evaporation, but the unshaded soil would lose moisture in the summer and whenever it lacked snow cover in winter, it would dry and harden thus favoring weeds and other invasives over native grasses and forbs, and erosion would increase. Plant and animal diversity would decrease. Population imbalances would increase. A Canadian study found that south-facing slopes received, on average, five times the solar radiation as north-facing slopes and, as a result, produced much less runoff compared to north-facing slopes. In many areas, the study found that south-facing slopes produced no consequential runoff at all. Not surprisingly, south-facing slopes also have a much higher fire frequency. So the irony is that clear-cutting south-facing slopes for fire mitigation might also eliminate what little runoff potential there is, as tree cover is the only feature allowing these aspects to retain moisture. At the same time, clearcutting north-facing slopes might benefit runoff in limited applications, but have far less potential to mitigate fire frequency. The Lake District of northern England is indicative of what can happen to a landscape after its forests have been removed. Until recent restoration efforts began, centuries of clear-cutting had left this area almost completely devoid of trees. The result is a stark region of little more than sheep grass and rocks. The soil has become so paper thin that there is little left to erode. Travelers are continually making new trails, as even a few passes expose the loose rocky substrate. Wildlife is almost nonexistent; the climate, unmoderated and severe. Imagine what would happen if Colorado took this scheme to its logical extreme. We know that most of our water supply comes from snowpack and not rain. Significantly reducing forest cover, combined with global warming, itself exacerbated and ignored by the same industry-government alliance, would further skew our precipitation mix toward rain. The long-term effect would not be increased water supply for developers, but the desertification of the eastern half of our state. Less snow, less overall precipitation, less ground source recharge, altered and desertified ecosystems - these are just some of the consequences of this scheme. There will almost certainly be others. Of course, if recent official attitudes are any indication, even desertification and the drying up of much of our water supply would not hold developers back. This is an indication of where both the real problem and real solution lie. Clear-cutting and other supply-side schemes of developers and conservatives could be compared to buying new and shinier buckets rather than fixing the hole in the roof. Proposals for new containments, whether or not they prove temporarily effective, merely distract us from considering the kinds of growth controls necessary to get a real handle on our water supply problems. Only after controlling demand will efforts at securing an adequate supply have any hope of success. Meanwhile, instead of clear-cutting, the logical course might be to uniformly thin smaller-bore trees across all slopes, while removing brush and litter. This would decrease fire severity and modestly increase runoff opportunity, while maintaining the hydrological cycle, ground source recharge, shade, biodiversity and habitat. Doing so at lower elevations would aid fire mitigation, while thinning at higher elevations might improve runoff. |
Speakout: Clear-cutting for runoff 'delusional'
In article , writes: The notion of clear-cutting huge tracks of forest to increase runoff for water containments is not only self-serving industry pandering, but delusional. While supporters hold up one carefully chosen test where some limited success was realized, the practical, real world effects would be quite different. Rather than being net depleters of moisture, trees and forests help increase moisture by "fixing" it in ground and surface sources. Trees use some of the moisture from snow in their upper stories while, aided by gravity, sun and wind, they permit most to find its way to the surface. This surface moisture is then shaded from excessive evaporation by the trees, allowing it to percolate downward, maintaining soil moisture balance, feeding root systems, reducing erosion, and recharging ground sources. Evapotranspiration from trees helps maintain the water cycle and local climate. Do you have any actual research to back this position? What?? = Evapotranspiration maintaining the water cycle and local Climate Generally I am of the opinion that any ground that can grow trees should be growing trees, but in some areas of the world trees are discouraged because of the amount of water they use. The article was in response to the Option of Clear-cutting tress to increase run off for storage behind Dams! I have talked to a farmer in South Africa who was not allowed to plant trees in a riparian zone because of the amount of water they would consume. The one I saw was they were removing non-natives in Sought Africa which sucked up water and crowded out Natives! Surprise = Surprise: Colorado has just banned The sale of Russian Olive Trees! It takes about 20" of rain a year to grow a douglas fir. I'm sure the Rocky Mountain pines are more frugal with their water, but just about have to consume around a foot of rainfall a year. Their concern was that the snow would not fall on to the ground and would melt in the trees and evaporate! What the result of logging would be on water supply is not clear to me. I suspect it would be highly variable depending on slope and climate. They want increased run off! Probably the most effective way for Colorado to recover water is just to outlaw lawn irrigation. Well in Denver, the rat catchers are called out everytime someone plants Native Grass which gets too high = Menawhile in the House next dorr the wood and trash pile is ignored - That would be where the rats would be! Saw Denver Parks trucks out watering ground with no tress but which had flowers during the summer - this was last week and not needed - They watered heavy = Not a good example! -- http://home.teleport.com/~larryc |
Speakout: Clear-cutting for runoff 'delusional'
In article ,
writes: I have talked to a farmer in South Africa who was not allowed to plant trees in a riparian zone because of the amount of water they would consume. The one I saw was they were removing non-natives in Sought Africa which sucked up water and crowded out Natives! In eastern Oregon, juniper is well known as a water thief. It's a major effort, but watershed improvement projects often involve Juniper eradication. It's expensive, because the trees are small, the wood is inferior and there is no market for it. It is possible to substantially enhance stream flows, but it involves killing off thousands of acres of juniper. Willow is another heavy water user. When pioneers encountered a seep or bog, it was common to plant a willow in it to dry it up. -- http://home.teleport.com/~larryc |
Speakout: Clear-cutting for runoff 'delusional'
The "water thief" concept is a bizarre one for me. I understand removing
invasive non-native species that can dominate riparian zones - tamarisk for example - but just whose water is being stolen? Cattle? Irrigators? And who had it before cattle and irrigators? Buffalo and jackrabbits? What is the water balance between what used to be available to streams and basins (i.e. fish) before settlement and now. Is juniper invasive in sage? It would seem they'd have very different water requirements. I recall that BC watershed study. It's been used to promote logging in city watersheds around here. It requires very skilled forestry and limited entry to work right. "Larry Caldwell" wrote in message ... In article , writes: I have talked to a farmer in South Africa who was not allowed to plant trees in a riparian zone because of the amount of water they would consume. The one I saw was they were removing non-natives in Sought Africa which sucked up water and crowded out Natives! In eastern Oregon, juniper is well known as a water thief. It's a major effort, but watershed improvement projects often involve Juniper eradication. It's expensive, because the trees are small, the wood is inferior and there is no market for it. It is possible to substantially enhance stream flows, but it involves killing off thousands of acres of juniper. Willow is another heavy water user. When pioneers encountered a seep or bog, it was common to plant a willow in it to dry it up. -- http://home.teleport.com/~larryc |
Speakout: Clear-cutting for runoff 'delusional'
The "water thief" concept is a bizarre one for me. I understand removing invasive non-native species that can dominate riparian zones - tamarisk for example - but just whose water is being stolen? Cattle? Irrigators? And who had it before cattle and irrigators? Buffalo and jackrabbits? What is the water balance between what used to be available to streams and basins (i.e. fish) before settlement and now. Is juniper invasive in sage? It would seem they'd have very different water requirements. I recall that BC watershed study. It's been used to promote logging in city watersheds around here. It requires very skilled forestry and limited entry to work right. Years Ago, the Politcos in Colorado wanted to clear-cut most of the Aspen trees becuase they felt that the trees used too much water! "Larry Caldwell" wrote in message t... In article , writes: I have talked to a farmer in South Africa who was not allowed to plant trees in a riparian zone because of the amount of water they would consume. The one I saw was they were removing non-natives in Sought Africa which sucked up water and crowded out Natives! In eastern Oregon, juniper is well known as a water thief. It's a major effort, but watershed improvement projects often involve Juniper eradication. It's expensive, because the trees are small, the wood is inferior and there is no market for it. It is possible to substantially enhance stream flows, but it involves killing off thousands of acres of juniper. Willow is another heavy water user. When pioneers encountered a seep or bog, it was common to plant a willow in it to dry it up. -- http://home.teleport.com/~larryc |
Speakout: Clear-cutting for runoff 'delusional'
Larry Caldwell writes:
In article , writes: The notion of clear-cutting huge tracks of forest to increase runoff for water containments is not only self-serving industry pandering, but delusional. snip Do you have any actual research to back this position? Generally I am of the opinion that any ground that can grow trees should be growing trees, but in some areas of the world trees are discouraged because of the amount of water they use. I have talked to a farmer in South Africa who was not allowed to plant trees in a riparian zone because of the amount of water they would consume. I think the idea behind this scheme only would apply to east slope areas that are prone to chinook winds. I recall several studies in Alberta that showed a net moisture gain from an east-slope area that had a patchwork of small clearcuts. I don't have any references handy, but might be able to find them if anyone is interested. The mechanism was that all the winter snow in the small clearcuts reached the ground and was protected from evaporation by the surrounding trees, while the undisturbed area lost about 1/3 of the snow moisture to evaporation over the winter, as almost all the snow held in the crown branches evaporated. This effect was lost in openings over about 20 ha in size, because the sheltering effect of surrounding bush was lost in larger openings. I have no idea what effect on the downwind water cycle this might have if undertaken on a large scale. -- Larry Stamm http://www.larrystamm.com |
Speakout: Clear-cutting for runoff 'delusional'
In article ,
writes: The "water thief" concept is a bizarre one for me. I understand removing invasive non-native species that can dominate riparian zones - tamarisk for example - but just whose water is being stolen? Cattle? Irrigators? And who had it before cattle and irrigators? Buffalo and jackrabbits? What is the water balance between what used to be available to streams and basins (i.e. fish) before settlement and now. Is juniper invasive in sage? It would seem they'd have very different water requirements. It's all management, Mike. Fish and sage grouse are having a hard time, while there is no shortage of juniper or the species that eat juniper berries. In areas that get less than 15" of rainfall a year, juniper will exterminate all competing vegetation, including sage. It's interesting that you mention buffalo, because buffalo kill trees. The Great Plains are a fossil artifact of the great buffalo herds that used to kill off all the trees. Now that the buffalo are gone, trees are encroaching on areas that are not farmed or disturbed. It takes a while for a seed reservoir to build up, but 500 years from now the Great Plains will be the Great Central Forest. -- http://home.teleport.com/~larryc |
Speakout: Clear-cutting for runoff 'delusional'
"Larry Caldwell" wrote in message ... In article , writes: The "water thief" concept is a bizarre one for me. I understand removing invasive non-native species that can dominate riparian zones - tamarisk for example - but just whose water is being stolen? Cattle? Irrigators? And who had it before cattle and irrigators? Buffalo and jackrabbits? What is the water balance between what used to be available to streams and basins (i.e. fish) before settlement and now. Is juniper invasive in sage? It would seem they'd have very different water requirements. It's all management, Mike. Fish and sage grouse are having a hard time, while there is no shortage of juniper or the species that eat juniper berries. In areas that get less than 15" of rainfall a year, juniper will exterminate all competing vegetation, including sage. It's interesting that you mention buffalo, because buffalo kill trees. The Great Plains are a fossil artifact of the great buffalo herds that used to kill off all the trees. Now that the buffalo are gone, trees are encroaching on areas that are not farmed or disturbed. It takes a while for a seed reservoir to build up, but 500 years from now the Great Plains will be the Great Central Forest. The old explanation for the Great American Desert that I recall was wind - too much evapotranspiration to allow broadleaved trees except in valleys and on streams but ideal for grass. I wouldn't discount long term effects of fire, plowing or grazing either. Restoration experts have managed to bring back small parcels of pre-settlement plant communities just by fencing OUT the cattle. Pioneer graveyards usually held reservoirs of original plants that stopped abruptly at the fenceline. If juniper is advancing is it because of less grazing, less fire, less management or a change in climate? Succession should follow the usual rules. |
Speakout: Clear-cutting for runoff 'delusional'
In article ,
writes: The old explanation for the Great American Desert that I recall was wind - too much evapotranspiration to allow broadleaved trees except in valleys and on streams but ideal for grass. I wouldn't discount long term effects of fire, plowing or grazing either. Restoration experts have managed to bring back small parcels of pre-settlement plant communities just by fencing OUT the cattle. Pioneer graveyards usually held reservoirs of original plants that stopped abruptly at the fenceline. I'm sorry I jumped from discussing desert and sage brush to the great plains. It confused the issue. The part about the advance of forests into the plains had nothing to do with desert areas. Cattle are nowhere near as destructive of trees as bison. I think fire suppression has a lot to do with it too, since burning is a great way to maintain grasslands. I don't know what area they are talking about clearing in Colorado, but there is a good chance that some of it was not historically forested. Mountain bison were a separate, somewhat smaller strain than the plains bison that inhabited the mountain states. If juniper is advancing is it because of less grazing, less fire, less management or a change in climate? Succession should follow the usual rules. I think less fire is the biggest reason. Juniper has a very oily wood that burns like a candle. There is an article that gives some mention of juniper clearing at http://www.nv.blm.gov/bmountain/fore...front_page.htm It's a Nevada BLM site, but the difference between Nevada desert and Oregon desert is just a line on a map. The juniper discussion is about halfway down the page. -- http://home.teleport.com/~larryc |
Speakout: Clear-cutting for runoff 'delusional'
Larry Caldwell wrote in message t...
In article , writes: The "water thief" concept is a bizarre one for me. I understand removing invasive non-native species that can dominate riparian zones - tamarisk for example - but just whose water is being stolen? Cattle? Irrigators? And who had it before cattle and irrigators? Buffalo and jackrabbits? What is the water balance between what used to be available to streams and basins (i.e. fish) before settlement and now. Is juniper invasive in sage? It would seem they'd have very different water requirements. It's all management, Mike. Fish and sage grouse are having a hard time, while there is no shortage of juniper or the species that eat juniper berries. In areas that get less than 15" of rainfall a year, juniper will exterminate all competing vegetation, including sage. It's interesting that you mention buffalo, because buffalo kill trees. The Great Plains are a fossil artifact of the great buffalo herds that used to kill off all the trees. Now that the buffalo are gone, trees are encroaching on areas that are not farmed or disturbed. It takes a while for a seed reservoir to build up, but 500 years from now the Great Plains will be the Great Central Forest. It also has to deal with percipitation = seeing That The historical range of the bison was extensive, from Alaska, Washington, Oregon, and Canada south into the northern portions of the Mexican plateau, and eastward to the Atlantic seaboard states, and all land in-between. Before Europeans arrived, small herds of woodland bison inhabited almost all of Georgia, except the southwestern and coastal parts of the state and By 1819 all bison east of the Mississippi River were gone forever = I think we can say more factors than just Bison or no Bison effect the presence of trees on the great plains or in the deserts of the Sahara! |
Speakout: Clear-cutting for runoff 'delusional'
In article ,
writes: I think we can say more factors than just Bison or no Bison effect the presence of trees on the great plains or in the deserts of the Sahara! Once again, for the geographically challenged, the Great Plains of North America are not a desert. In fact, they are quite well watered. While the plains get steadily dryer as you move west, the east slope of the Rockies still gets 18 to 25 inches a year, with more rain falling in the south. -- http://home.teleport.com/~larryc |
Speakout: Clear-cutting for runoff 'delusional'
In article , writes: I think we can say more factors than just Bison or no Bison effect the presence of trees on the great plains or in the deserts of the Sahara! Once again, for the geographically challenged, the Great Plains of North America are not a desert. In fact, they are quite well watered. Not enough to grow a lot of crops in Colorado without water! While the plains get steadily dryer as you move west, the east slope of the Rockies still gets 18 to 25 inches a year, with more rain falling in the south. Is that why it is called the Great American Desert? |
Speakout: Clear-cutting for runoff 'delusional'
Is that why it is called the Great American Desert? That was the old term the pioneers used for everything between the Cascades and the treeline halfway across Missourra. Pre Bureau of Reclamation, it was effectively a desert unless you found some bottomland. |
Speakout: Clear-cutting for runoff 'delusional'
Is that why it is called the Great American Desert? That was the old term the pioneers used for everything between the Cascades and the treeline halfway across Missourra. Pre Bureau of Reclamation, it was effectively a desert unless you found some bottomland. A tree line also maintained by fire! |
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