I think an even more interesting study would be gradient analyses of moisture, temperature, UV at the geographic extents of the bristlecones (lats, longs, elevations).
One of the questions posed in a ecological restoration class I took was "How will global climate change impact the geographic extents of _____________(choose a species)". My choice was Quaking Aspen (Populus tremuloides) in Northern Arizona on San Francisco Peaks...I predicted that the aspen were somewhat less mobile, that they were likely to die out at lower elevations due to increased predation by forest pathogens with rising temperatures, and to stabilize at higher elevations. Lots more to it than that, but the idea is that it just takes a few degrees (in this case adiabatic temperature change) change to have significant impact on many facets of an ecosystem. When enough of those subtle 'facets' accumulate, major differences will be noticed. Particularly at the geographic extents, where the natural limits already in place get exceeded.
Attaching an image of bristlecones as they reach the edge of their 'ecotone'...
-Don
Date: Tue, 17 Nov 2009 13:05:58 -0800
From: eli_dicker...@yahoo.com
Subject: [ENTS] Bristlecone Pines as signals of climate change
To: entstrees@googlegroups.com
That's really interesting Don. Being at the southern extent of the natural range of Tsuga canadensis here in Atlanta I wonder what the boundaries of their range were in years past (pre-Adelgid) and if they were truly native to places like old growth Fernbank Forest here in the city. You're right though- there are many factors at play here, affecting many different facets in the ecosystem. Kind of mind boggling to think about.
Eli
--- On Tue, 11/17/09, DON BERTOLETTE <forestorat...@msn.com> wrote:
From: DON BERTOLETTE <forestorat...@msn.com>
Subject: RE: [ENTS] Bristlecone Pines as signals of climate change
To: entstrees@googlegroups.com
Date: Tuesday, November 17, 2009, 2:41 PM
Eli-
I think an even more interesting study would be gradient analyses of moisture, temperature, UV at the geographic extents of the bristlecones (lats, longs, elevations).
One of the questions posed in a ecological restoration class I took was "How will global climate change impact the geographic extents of _____________(choose a species)". My choice was Quaking Aspen (Populus tremuloides) in Northern Arizona on San Francisco Peaks...I predicted that the aspen were somewhat less mobile, that they were likely to die out at lower elevations due to increased predation by forest pathogens with rising temperatures, and to stabilize at higher elevations. Lots more to it than that, but the idea is that it just takes a few degrees (in this case adiabatic temperature change) change to have significant impact on many facets of an ecosystem. When enough of those subtle 'facets' accumulate, major differences will be noticed. Particularly at the geographic extents, where the natural limits already in place get exceeded.
Attaching an image of bristlecones as they reach the edge of their 'ecotone'...
-Don
Date: Tue, 17 Nov 2009 13:05:58 -0800
From: eli_dicker...@yahoo.com
Subject: [ENTS] Bristlecone Pines as signals of climate change
To: entstrees@googlegroups.com
A lot can be found out regionally I suspect. I know that when seeking reference conditions for the forested ecosystems of Grand Canyon National Park, we tapped all the historical accounts (narratives and photographs), and then natural reference conditions by proxy (macrofossil analysis, pollen analysis) and found that the four forest ecosystems on the North Rim/Kaibab Plateau; pinon-juniper, pure ponderosa, mixed conifer, and spruce fir had "marched" up and down the plateau several kilometers, at several different times in the preceding 12,000 years, in response to changing climatic conditions.
Palynology is a pretty cool thing for assessing vegetation presence/absence over time, especially if you have relatively undisturbed ponds, lakes, or bogs to gather data from.
-Don
Date: Wed, 18 Nov 2009 07:01:36 -0800
From: eli_dicker...@yahoo.com
Subject: RE: [ENTS] Bristlecone Pines as signals of climate change
To: entstrees@googlegroups.com
That's really interesting Don. Being at the southern extent of the natural range of Tsuga canadensis here in Atlanta I wonder what the boundaries of their range were in years past (pre-Adelgid) and if they were truly native to places like old growth Fernbank Forest here in the city. You're right though- there are many factors at play here, affecting many different facets in the ecosystem. Kind of mind boggling to think about.
Eli
--- On Tue, 11/17/09, DON BERTOLETTE <forestorat...@msn.com> wrote:
From: DON BERTOLETTE <forestorat...@msn.com>
Subject: RE: [ENTS] Bristlecone Pines as signals of climate change
To: entstrees@googlegroups.com
Date: Tuesday, November 17, 2009, 2:41 PM
Eli-
I think an even more interesting study would be gradient analyses of moisture, temperature, UV at the geographic extents of the bristlecones (lats, longs, elevations).
One of the questions posed in a ecological restoration class I took was "How will global climate change impact the geographic extents of _____________(choose a species)". My choice was Quaking Aspen (Populus tremuloides) in Northern Arizona on San Francisco Peaks...I predicted that the aspen were somewhat less mobile, that they were likely to die out at lower elevations due to increased predation by forest pathogens with rising temperatures, and to stabilize at higher elevations. Lots more to it than that, but the idea is that it just takes a few degrees (in this case adiabatic temperature change) change to have significant impact on many facets of an ecosystem. When enough of those subtle 'facets' accumulate, major differences will be noticed. Particularly at the geographic extents, where the natural limits already in place get exceeded.
Attaching an image of bristlecones as they reach the edge of their 'ecotone'...
-Don
Date: Tue, 17 Nov 2009 13:05:58 -0800
From: eli_dicker...@yahoo.com
Subject: [ENTS] Bristlecone Pines as signals of climate change
To: entstrees@googlegroups.com
I was able to see a preview of this paper. This paper is a limited
gradient analysis. That is to say, the authors examined trees across a
a small elevational gradient in the White Mountains. Tree ring theory
predicts that only those trees at the top of the mountain, at forest
tree line, will be mostly sensitive to temperature. Specifically, this
theory predicts that the change in ring widths of these upper
elevation trees will vary in a positive manner to changes in
temperature. Because of cool summer temperatures, a short growing
season and cold winters, rings in these trees will become wider when
it is warmer annually or seasonally and narrower when it is colder.
Eras of cooler temperatures ought to be reflected with longer-trends
of narrower rings and vice-versa. This theory of site location also
predicts that trees at lower elevations will be varyingly sensitive to
temperature and precipitation and at the lowest elevations, trees will
be mostly drought sensitive [positive correlation to precipitation and
negative to temperature].
Trees at slightly lower elevations do not show the trend of wider
growth rings over the last 50 years. The lower elevation trees are
also shown in this paper to be more positively correlated to
precipitation and negatively correlated to temperature, while the
treeline trees in the White Mountains and two bristlecone treeline
sites in the region are primarily positively correlated to
temperature. Thus, these results indicate that temperature is a main
factor in driving the increased ring widths over the last 50 yrs.
Some might argue that elevated CO2 is responsible for the trends in
this paper and it cannot be entirely ruled out. However, data
presented here, though mostly circumstantial, indicates CO2 is not the
most important factor of the recent growth trend. See, it is predicted
that elevated CO2 will increase the ability of trees & plants to use
water more efficiently and possibly grow higher than they might
normally in similar droughty conditions, but at lower CO2
concentrations. Higher CO2 concentrations increases water use
efficiency by allowing plants to keep their stomates more closed,
which allows them to bring in the same amount of CO2 while losing less
water through their stomates.
As discussed above, lower elevation bristlecone pine are generally
drought stressed - their ring widths are negatively correlated to
temperature [like a panting dog] and positively correlated to
precipitation [like that same dog walking across a desert - it needs
water!]. Thus, these trees should benefit by the higher levels of
plant food - CO2. Yet, in this study, the raw ring widths of lower
elevational bristlecone pine do not show the same increase in growth.
This result argues against CO2 fertilization. A test of isotopic
ratios in the rings of these trees, a test that was not performed,
will help determine if CO2 is an important factor of the main finding
here. That test needs to be done so the role of CO2 can be better
understood.
> I think an even more interesting study would be gradient analyses of moisture, temperature, UV at the geographic extents of the bristlecones (lats, longs, elevations).
> One of the questions posed in a ecological restoration class I took was "How will global climate change impact the geographic extents of _____________(choose a species)". My choice was Quaking Aspen (Populus tremuloides) in Northern Arizona on San Francisco Peaks...I predicted that the aspen were somewhat less mobile, that they were likely to die out at lower elevations due to increased predation by forest pathogens with rising temperatures, and to stabilize at higher elevations. Lots more to it than that, but the idea is that it just takes a few degrees (in this case adiabatic temperature change) change to have significant impact on many facets of an ecosystem. When enough of those subtle 'facets' accumulate, major differences will be noticed. Particularly at the geographic extents, where the natural limits already in place get exceeded.
> Attaching an image of bristlecones as they reach the edge of their 'ecotone'...
> -Don
> Date: Tue, 17 Nov 2009 13:05:58 -0800
> From: eli_dicker...@yahoo.com
> Subject: [ENTS] Bristlecone Pines as signals of climate change
> To: entstrees@googlegroups.com
Thanks so much for your insight Neil- that helps explain things quite a bit! Things are never quite as black and white as they first appear I guess!
~Eli
--- On Thu, 11/19/09, neil <mocker...@gmail.com> wrote:
From: neil <mocker...@gmail.com>
Subject: [ENTS] Re: Bristlecone Pines as signals of climate change
To: "ENTSTrees" <entstrees@googlegroups.com>
Date: Thursday, November 19, 2009, 3:50 AM
Hi Don, Eli, ENTS,
I was able to see a preview of this paper. This paper is a limited
gradient analysis. That is to say, the authors examined trees across a
a small elevational gradient in the White Mountains. Tree ring theory
predicts that only those trees at the top of the mountain, at forest
tree line, will be mostly sensitive to temperature. Specifically, this
theory predicts that the change in ring widths of these upper
elevation trees will vary in a positive manner to changes in
temperature. Because of cool summer temperatures, a short growing
season and cold winters, rings in these trees will become wider when
it is warmer annually or seasonally and narrower when it is colder.
Eras of cooler temperatures ought to be reflected with longer-trends
of narrower rings and vice-versa. This theory of site location also
predicts that trees at lower elevations will be varyingly sensitive to
temperature and precipitation and at the lowest elevations, trees will
be mostly drought sensitive [positive correlation to precipitation and
negative to temperature].
Trees at slightly lower elevations do not show the trend of wider
growth rings over the last 50 years. The lower elevation trees are
also shown in this paper to be more positively correlated to
precipitation and negatively correlated to temperature, while the
treeline trees in the White Mountains and two bristlecone treeline
sites in the region are primarily positively correlated to
temperature. Thus, these results indicate that temperature is a main
factor in driving the increased ring widths over the last 50 yrs.
Some might argue that elevated CO2 is responsible for the trends in
this paper and it cannot be entirely ruled out. However, data
presented here, though mostly circumstantial, indicates CO2 is not the
most important factor of the recent growth trend. See, it is predicted
that elevated CO2 will increase the ability of trees & plants to use
water more efficiently and possibly grow higher than they might
normally in similar droughty conditions, but at lower CO2
concentrations. Higher CO2 concentrations increases water use
efficiency by allowing plants to keep their stomates more closed,
which allows them to bring in the same amount of CO2 while losing less
water through their stomates.
As discussed above, lower elevation bristlecone pine are generally
drought stressed - their ring widths are negatively correlated to
temperature [like a panting dog] and positively correlated to
precipitation [like that same dog walking across a desert - it needs
water!]. Thus, these trees should benefit by the higher levels of
plant food - CO2. Yet, in this study, the raw ring widths of lower
elevational bristlecone pine do not show the same increase in growth.
This result argues against CO2 fertilization. A test of isotopic
ratios in the rings of these trees, a test that was not performed,
will help determine if CO2 is an important factor of the main finding
here. That test needs to be done so the role of CO2 can be better
understood.
> I think an even more interesting study would be gradient analyses of moisture, temperature, UV at the geographic extents of the bristlecones (lats, longs, elevations).
> One of the questions posed in a ecological restoration class I took was "How will global climate change impact the geographic extents of _____________(choose a species)". My choice was Quaking Aspen (Populus tremuloides) in Northern Arizona on San Francisco Peaks...I predicted that the aspen were somewhat less mobile, that they were likely to die out at lower elevations due to increased predation by forest pathogens with rising temperatures, and to stabilize at higher elevations. Lots more to it than that, but the idea is that it just takes a few degrees (in this case adiabatic temperature change) change to have significant impact on many facets of an ecosystem. When enough of those subtle 'facets' accumulate, major differences will be noticed. Particularly at the geographic extents, where the natural limits already in place get exceeded.
> Attaching an image of bristlecones as they reach the edge of their 'ecotone'...
> -Don
> Date: Tue, 17 Nov 2009 13:05:58 -0800
> From: eli_dicker...@yahoo.com
> Subject: [ENTS] Bristlecone Pines as signals of climate change
> To: entstrees@googlegroups.com
