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DOUG_LARSON

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About DOUG_LARSON

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  • Homepage
    www.uoguelph.ca/botany/cerg
  • Occupation
    professor
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    Guelph, Ontario, Canada
  1. Impact study shows climbing damages ecosytems

    Hi Fern, Thanks for the reference. Doug Larson
  2. Impact study shows climbing damages ecosytems

    Hi Fern, could you give me the reference to this study. We study everything there is to know about cliffs. Doug
  3. Impact study shows climbing damages ecosytems

    No, what we actually do is use the instrumental record for the past 140 or so years from stations immediately adjacent to the cliffs. Unlike chronologies from alpine areas out west, we have lots of stations in proximity to the cliffs and at the same altitude so their is no adiabatic effect. Then we create a master chronology by taking hundreds of cores from different microsites. We presume that the site specific and tree-specific effects will represent the noise in any signal that is there and then we statistically hunt for the common signal. We usually only admit trees to the chronology when 50% or more of the annual variance is correlated with the master chronology. The individual tree correlations have a common signal that goes as high as 80%. Once the master chronology is built, we then do a correlation analysis with as many factors in the 140 years worth or record as we can. IN the case of the cedar trees on the escarpment, it initially turned out that maximum summer (JUNE to AUG) temperatures of the previous year was the factor that best explained the chronology. Since that time, an even better fit has been produced for the long chronology (2787 yrs) based on the Palmer drought sensitivity index that combines data for both temp. and precip. The real problem with chronology construction is that we are formed to assume homology between recent climatic - physiological responses and historic ones. We have no evidence of evolutionary change in these relationships, but it is still a declared assumption that , if wrong, would invalidate the chronology as a proxy index of past climates. The pollen, sediment and ice cores suffer from the same problems so we're actually no worse off. Plus, our signals are patently annually resolvable - something that is hard to prove for ice, pollen or sediments.
  4. Impact study shows climbing damages ecosytems

    I almost hate to mention this, considering the response to our other work on this forum . We do dendrochonology on the ancient cliff trees and have produced some of the longest tree-ring chronologies for north america from these trees. The signal (2787 years long) clearly shows the warming and drying signal, but also shows past episodes that were equally large. I will not get into the debate about natural or anthropodenic climate change here. But I will point out that the trees on the cliffs generated the data. How many of these trees can we afford to lose to climbing? I don't know but at least we now know that the trees cannot benefit from recreational activity.
  5. "Rock Climbing Wrongs" on the Niagara Escarpment

    Nope. But even if I were, he'd probably deny it. doug larson
  6. "Rock Climbing Wrongs" on the Niagara Escarpment

    I don't want to sound like a motivational speaker, but "only the impossible is impossible". Our species is built for survival and if there is a trend to try to globally protect that which keeps us alive and healthy, I believe that that trend will eventually surface. I may not be part of the subspecies that achieves this success, but I'm trying. doug
  7. Impact study shows climbing damages ecosytems

    HI Klenke, You're quite right to point out that Curry killed what was at the time the oldest living thing. As far as Methusela is concerned, the 'currently' oldest living Bristlecones are evaluated using increment boring. They too are near 4900 years but in most cases the pith (the centre of the tree) is lost so all we have are maximum ring counts. When one gets near 5000, who cares, they all incredibly old. There has been some recent published reports of ancient fungi and ancient cresote bushes. These estimates talk about 12000 year old organisms. I have written a paper about this in Journal of Experimental Gerontology (I can send you a reprint if you'd like) in which I point out that for both the fungi and creosote bush stories the clonally expanding plant might be part of genome that is 12000 years old, but the branches of what you'd call the bush are no more than 20 years. In the case of the fungus, the tissue is no more than 1 year old. If we allow clonally expanding organisms to be included in this discussion, then E. coli bacteria are probably millions of years old since they've been expanding clonally for that time or more. Doug Larson
  8. Impact study shows climbing damages ecosytems

    Hi Verve, Thanks, whoever you are. doug larson
  9. "Rock Climbing Wrongs" on the Niagara Escarpment

    quote: Originally posted by klenke: Last line of Michelle's commentary on her website:"...we just want to see a healthy relationship between climbers and natural cliff communities." Hmmmm. I now see the real reason why climbers fall off cliffs and die. It's not because the climbers made boneheaded decisions or got unlucky by falling rock. No, it's the little snails. These snails are killers. They send climbers to their death. They're just getting even for all that habitat the climbers are killing. Perhaps some of the snails are suicide snails. This has got to stop. Can't we all just get along? Can't we once again have a heathly relationship? Can't man and snail again live in peace? Hi Klenke, I had thought that I had made some progress at convincing you that logic and reason ought to replace hyperbole and acrimony. Obviously not. The level of sarcasm in your post is astonishing. The land snails include some very rare species. What gives you the right to decide that your life and enjoyment of physical activity is more important than theirs? I urge you to re-think your position. I am happy to re-think mine - tell me what's wrong with it - only tell me without sarcasm. doug larson
  10. Impact study shows climbing damages ecosytems

    quote: Originally posted by klenke: Hey, Mr. Larson, we talked about old old trees about three weeks ago on this site (thread titled, "So you think Beckey's old"). I'm sure you already know about the bristlecone pine. From old thread:World's longest living thing: Methuselah.4,800 years old +/-. Twice as old as the average elder redwood or sequoia.See: http://www.sonic.net/bristlecone/Or: http://www.pbs.org/wgbh/nova/methuselah/ Hi again Klenke, You might not know this story, but in 1964 a scientist by the name of Curry was doing field work in the white Mts. He had been interested in coring Bristlecones to do dendrochronology. The Nat. park service reportedly gave him permission to cut down one (1) tree if he had to. As luck would have it, his cored got stuck after a few trees and he had to cut the tree to retrieve the corer. When counted, it turned out that he had killed the oldest living thin ever found. It was over 4900 years. He never continued doing dendro. doug larson
  11. Impact study shows climbing damages ecosytems

    quote: Originally posted by klenke: I second what Dru is saying. The Niagara Escarpment and Pacific Northwest escarpments are two completely different 'animals' and correlation between the two should not be made until BOTH have been studied with equal measure. And that is exactly what my original concern was: that those who would make legislation, etc. could do so without knowing the facts. Instead, they make "changes" based on what they think they know based on a journal article that abridged the issue so much it actually altered its face value. Hi Klenke, There has been no work done to show the degree to which west coast cliffs are similar to or different from eastern ones. If you know of such studies, please let me know. What you say might very well be true, but until someone carefully looks, how will anyone know? doug larson
  12. Impact study shows climbing damages ecosytems

    quote: Originally posted by Dru: OH MY GOD I AGREE WITH PETER PUGET OVER SOMETHING? what next? maybe I will start drinking lagers or give up trad climbing No: here's my point, which I have alluded to but not made directly. Doug and Michelle, please comment. Everything I have seen about this issue has reported it as: "Rock climbing severely damages cliff ecosystems". Which may be true for the area studied. i havent read the full paper so I won't comment. What I'm concerned about is the potential this paper may have if it is used by policy makers to govern climbing in an area other than on the Niagara Escarpment. I have no doubt that climbing on West Coast area cliffs does impact vegetation - mostly during route preparation and the first ascent when trees are cut or pruned back, moss and lichen is scrubbed and dirt is removed from cracks. However: 1) the trees, vegetation and lichen found on West Coast cliffs, based on my undergrad biogeography experience, does not seem to represent a differing ecosystem from non-cliff adjacent areas on the West Coast; NONE OF THIS HAS BEEN QUANTITATIVELY STUDIED. WE HAVE BEEN TRYING TO ENCOURGE AS MANY OTHERS AS POSSIBLE TO STUDY THE ECOLOGY OF CLIFFS, BUT THERE HAVE BEEN FEW TAKERS. IT'S A VERY COOL SUBJECT IF ANY OF YOU HAVE BIOLOGICAL INCLINATIONS. WE DON'T CARE IF WEST COAST RAINFOREST CLIFFS ARE THE SAME AS EASTERN ONES OR NOT. WE LOVE ALL CLIFFS AND, BELIEVE IT OR NOT, WE LOVE THE PEOPLE WHO CLIMB ON THEM. BUT WITHOUT WRECKING STUFF! 2) the trees growing on cliffs on the West Coast are demonstrably not ancient; BY WHAT DEMONSTRATION? 3) there are many cliff faces on the West Coast and only a few have been impacted by climbing development I would say less than 1% of cliffs within 50kms of Vancouver are climbed on. so the impact climbers have HERE is not seriously impacting the overall local cliff ecosystem; MAYBE SO, BUT THE TIME CONSTANTS FOR CLIFF RESTORATION MAY BE MUCH LONGER. PLUS WE KNOW THAT THERE ARE LOTS OF ENDEMIC SPECIES ON CLIFFS AND WE DO NOT KNOW IF THEIR POPULATIONS DEPEND ON ADJACENT STANDS THAT ARE ALSO UNDISTURBED. 4) if a route does not get repeated frequently on the West Coast, it regrows vegetation rapidly. BUT WHAT IS THE VEGETATION? IS IT NATIVE OR ALIEN. THERE IS VEGETATION ON THE NIAG. ESCARPMENT CLIFFS TOO, BUT ITS MAINLY ALIEN.. I have seen moss inches thick regrow on climbs within two years of their being cleaned simply because they did not recieve enough traffic or were not of the climbing quality to become popular routes. So the potential impact from cleaning a route is acceptable to me as a first ascencionist, in that it is demonstrably not permanent. MAYBE SO, BUT SHOULDN'T POLICY BE BASED ON EVIDENCE RATHER THAN ANECDOTE? So I guess my pint for Doug and Michelle is that I would like to see recognition of the specific spatial limitations to their study area so that people dont apply their work out of context to areas that they did not study, which may behave in a cpmpletely different manner to the studied area. I happen to work in the resource management field (on the regulatory side) and one of my biggest criticisms of much of the science I see is that results of a study done on a limited area are applied out of context, ie a biologist working for a logging company does a study that shows a small amount of logging improves fish habitat in a specific area, and the logging company then tries to do a lot of logging along streams in a much larger and climactically different area on the grounds that "we have shown that logging improves fish habitat". THE DEGREE TO WHICH PEOPLE USE OUR RESULTS TO FORM POLICY IS SOMETHING WE CAN'T CONTROL. WE ASKED THE QUESTION, GOT THE RESULTS, AND PUBLISHED THEM. WE ARE NOT STANDING ON SOAP BOXES CLAIMING TO ANYONE WHO WILL LISTEN THAT CLIMBING IS BAD. IT ISN'T AND WE WOULDN'T SAY THAT IT IS. IT IS CERTAIN BEHAVIOURS THAT ARE BAD AND ALL CLIMBERS SHOULD KNOW ABOUT THIS AND TALK ABOUT IT. DOUG LARSON
  13. Impact study shows climbing damages ecosytems

    This issue of tree age for trees in level ground is interesting. The oldest Chamaecyparis (yellow cedar) ever found is about 1600 years old. It was dead. The trees are normally so big that coring the living trees is impossible and even the cross sections are too large to handle. Tree ring counts have rarely been published for this species and the age estimates are almost always based on size. Can you give me the reference for the 1200 year old tree in level ground? I will bet that the age was estimated by girth and compared to known ages for smaller (corable) trees. I do this stuff for a living and I know that people outside of the the field of dendrochronology guess the ages of trees all the time. These ages are lovely, but wrong. What you must ask for when people claim evidence of great age, is an actual photograph of the section and a precise ring-count. If these items are not available, you should not believe the results because people WANT big trees to be old. Doug Larson
  14. Impact study shows climbing damages ecosytems

    Hi None; We can date the year of birth and death of trees on the cliffs using dendrochronology (tree ring dating). We have trees on the escarpment (dead ones) that have been hanging there for over 300 years. This may no apply to other cliff species, but the cedars and junipers are very very decay resistant. doug larson
  15. Impact study shows climbing damages ecosytems

    Hi Zen: What we have found so far is that the cliffs function on time scales and in many cases with organisms unlike the rest of the landscape. They are (as much as one can get in a terrestrial environment) THEIR OWN ECOSYSTEM. The rates of growth, the nnutrient cycling etc. all occur different than on level ground. Anyone who needs to take a leak while on belay will appreciate this. Ours is the only lab in the world that concentrates on cliffs, so I have to apologize for not knowing more. But we're trying. bye for now doug larson
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