The underlying question here must surely be:

'What kills trees - or at least prevents their successful growth and reproduction?'

Sometimes it can be the abiotic limiting factors that are directly changing due to climate change. But a factor at least as important is the impact of pathogens and insects. These impacts are changing in hard-to-predict ways due to new introductions and complex interactions between 'bug' species and climatic change.

This hard-to-predict (or model) change makes it tempting to set this issue aside and just concentrate on more tractable factors like precipitation or temperature, but I believe this is a mistake, for two reasons:

1. Those 'bug' interactions have significant effects on the impact of climate change - if a tree is under one stress, it is generally more affected by other kinds of stress. The biotic and abiotic interactions simply cannot be modelled separately.

2. If the biotic issues are so important, but hard-to-predict, any results that we produce from only considering the abiotic stresses are likely to be misleading, and lead us towards giving faulty advice.

I had heard a rumor that the pine trees in Alaska had moved up 500 feet in elevation

over a 50 year period. They need at least 1 month per year of complete frost free

conditions to complete their reproductive cycle.

Dear Michael,

thank you very much for your reply.

we are working on the global modelling of alder distribution and the effect of climate change on the distribution. we use four different climate change scenarios from IPCC and for each scenarios 4 different model outputs to investigate the climate change effect on the alder distribution. We assume, that a change of 30 years average of annual temperature and precipitation can affect the alder distribution. For example, a alder species occurs in a B location and this species occurs generally in a location in a range of annual average temp. between -10°C and 9°C and also precipitation between 300mm and 600mm. If the annual average temp and precipitation of a years fall out of the aforementioned temp. and precipitation range, then the alder species cannot occur in the B location any more. 30 years is just a empirical assumption. A lifespan of a alder species is between 60 and 120 years (~90 years on average). If the climate conditions of a location fall out of the climate requirements of the species after 1/3 of its lifespan, than this species cannot more distribute in this location. Do anybody have a publication to cite for the 30 years assumption?

OK we have your question more defined here. You say: "For example, a alder species occurs in a B location and this species occurs generally in a location in a range of annual average temp. between -10°C and 9°C and also precipitation between 300mm and 600mm. If the annual average temp and precipitation of a years fall out of the aforementioned temp. and precipitation range [for 30 years], then the alder species cannot occur in the B location any more". The temperature and precipitation limits I assume represent existing empirical data and the 30 years is surely the hypothesis (as a model assumption) you should be testing using historical climate data if available. It is unlikely that anyone has the 30 years as empirical data for alder; if they did you could test their result. Has anyone got an empirical result of 30 years for other species is maybe what you really want?

Dear Abdulla,

There is a considerable amount of data on plant migration as a result of the glacial-interglacial transition - a warming. Maybe you can extract rates from these data. One factor that I remember from that literature is the importance of seed dispersal mechanisms. Trees with wind dispersed seeds behave very different from trees that have seeds that are basically dispersed by rodents. Trees with floating seeds spread in a very different way again.

A second point of interest would be weather extremes rather than long-term changes in overall climate. A single weather extreme (a badly timed frost or drought ) may do more harm to / wipe out a population than a long term slight change in temperature or precipitation-evaporation balance.

Hello dear Gerard Versteeg

Recently I have observed that Prosopis Julifera is the thorny plant growing in India every where in all kinds of environmental consitions. But most of the drought and semi arid area is being coverd by these plants. before 20 years this area was covered by biannual weeds plants (Parthenium histreophorus etc) but these area are replaced by prosopis julifera which are thorny shrubs growing every where. According to my openion it is nothing but the process of ecological succession which will be converted in to tree stage of succession in near future. as these plant grows well in xeric condition, definitly it is good sign of ecological development. unfortunatly prosopis julifera plants are under great threat of exploitation as these are considerd as useless plants. naturally all plants requires CO2 for respiration. and incresed co2 level in atmosphere leads a development of Co2 dependent oranisms.(Plants) this development of p Julifera is simillar to that of Eutrophication of any aquatic body. So, I wanted to know that whether I am at righ way of thinking. i wanted suggessions from you in this regard.

I'd like to thank Peter Hargreaves for making the question more understandable.

Dear Gerard i also thank you for your reply. The method which i developed looks like a triangle area (see attachment). So that i already considered your hypothesis with extreme weather condition. As you see on the figure the developed triangle for the climate is narrower. On the figure i plotted the temperature and precipitation of 295 locations in which alnus species occur naturally. a small change on the temperature and precipitation in locations with extreme climate can cause a rapid harm to/ wipe out the alder.

Dear Abdulla, your figure seems to be alder distribution along temperature and precipitation gradient at a global scale--much wider niche than I originally thought, are they annual means? I do not know this specific subject well, but I have seen in field and read from earlier publications saying that Alnus are normally distributed close to river or in places with shallow ground water; thus, is it possible that local environment is even more important than regional climate?

Dear Yi Yin,

the influencing variables (i.e. temperature and precipitation) are annual means. Many of species occur not only close to water regions but also in regions with humid climate (e.g at high elevation on the Andes mountains). Or some species (e.g. Alnus cordata, A. incana, A. viridis) are adapted to warm dry or cold dry climate as well. Climate is surely not a single parameter that influence the distribution of Alnus. There are some other factor like plant association and/or soil conditions which effect the distribution of Alnus species. @Gerard, can you give please a example data base where i can find paleo data for the distribution of Alnus?

There are many dendrochronological studies on this topic, I suggest to see inside this database: http://www.wsl.ch/dienstleistungen/produkte/glossare/dendro_bibliography/index_EN

Dear Dr. Vidhin Kamble,

I am not an expert in the region you are talking about - I understand the region is semi-arid. I can think of several scenarios that may play a role in the succession you are describing. 1. It could be that the land-use has changed (e.g. fire frequency, grazing), in that case the vegetation change you see is not a response to climate change at all. 2. In case this is not so, climate may have changed, in a semi-arid area I would guess that precipitation is the limiting factor for woody plants. 3. Finally it is possible that increased CO2 level in the atmosphere changed the competition between plants. For this we have to consider the CO2 fixation pathways of C3 and C4 plants. C3 plants are most plants, including many woody plants. C4 plants are all herbs, many Amaranthaceae, Chenopodiaceae and Poaceae. C3 plants fix the CO2 into an organic C3-compound directly from the atmosphere using the enzyme Rubisco. This enzyme is not terribly efficient and the backwards reaction becomes relatively more important under low CO2 levels and at high temperatures. To keep the CO2 levels in the leaf high, the C3 plants need to open their stomata a lot and at the same time they lose water through these stomata. C4 plants you can see as an adaptation to low CO2 levels, they fix the CO2 with an enzyme that has an high affinity to CO2 and make a C4 compound, they transport this compound to a compartment which is gas-tight and release the CO2 again, creating locally a high CO2 concentration. Here Rubisco is used to fix the CO2 in the same C3 compound as C3 plants do. Since C4 plants capture the CO2 more efficiently from the atmosphere, they don't have to care as much about low CO2 levels in the leaf and can close their stomata more often - and loose less water. However, the extra metabolic steps for creating a C4 compound cost extra energy. As a result, C4 plants don't compete well for light with C3 plants. Now, if we increase the CO2 level of the atmosphere, the C3 plants benefit more than the C4 plants since the CO2 fixing efficiency of the latter is not increasing and of C3 plants it does. The C3 plants also don't need to open their stomata as much anymore, conversely loose less water, and survive better in more arid environments. In case the C3 plants are woody, they will overshadow the C4 plants, which will perform less well, probably consume less water etc. Be aware that from the glacial period to the interglacial period, CO2 levels also increased by 1/3.

I hope this is of use to you.

Gerard

One more issue that can not be forgotten is that interspecific competition may also affect the future distribution of plant species under climate change

As pointed out in this discussion, plant migration depends upon shifting climate conditions that favour successful regeneration of seeds in 'newer' areas, which is influenced not only by weather but by other ecological and environmental factors that permit establishment of the new cohort of plants -- soil moisture and nutrient conditions, competition with other species (pre-existing and newly arriving) and topographical barriers - for instance, sea level rise in the tropics can lead to mangroves encroaching inland, only if there is a very gentle topo gradient that allows seawater intrusion into groundwater. If the gradient is high, the groundwater will still be fresh and mangroves will be outcompeted by other exisiting species, and hence disappear.

nature is always find the ways that result in natural selection. Acceleration of climate changes by humans will promote or provoke an adaptation of each species in its environment. This species have its own characters (inherent and intrinsic values) and behaviors in order to survive in harsh habitat related to CC. Changes in duration either drought or flooding/wet conditions will lead to changes in performances or behavior (such as length of seed viability, thickness or size of leaves, short trunk, slow photosynthetic, etc) as responses to CC. Each species will response differently based on its ecological value.

Correlated to your question we couldn't just count on temperature and precipitation, because survival or adaptation of species is multifaceted effects. It is better if you pay attention on its limiting factors (remember The Law of the Minimum and the Law of Tolerance) including habitat requirements. These factors are primarily responsible for determining the growth and/or reproduction of species or population. It may be a physical factor such as temperature or light, a chemical factor such as particular nutrient, or a biological factor such as a competing species. if you have a previous database of certain species (autecology) corresponding to those factors, you could use it as a baseline and observe monthly (based on the seasons) of species response to at least 5-10 years for modelling. You will get a very good results correlated to your question. I hope it will help, good luck and success

Dear All,

thank you very much for the replies. As Hari mentioned, it is better and effective to find the limiting factor/s which effect the distribution of plant genus or species. That will help us to predict the plant migration depending on (maybe) climate parameters. I think, when the limiting factors are soil parameter, the plants will need a longer time to change its native area. Because the climate parameter are changed faster than soil parameter. We definitely a plant database with limiting factors of each plant association.

Best wishes to all

The underlying question here must surely be:

'What kills trees - or at least prevents their successful growth and reproduction?'

Sometimes it can be the abiotic limiting factors that are directly changing due to climate change. But a factor at least as important is the impact of pathogens and insects. These impacts are changing in hard-to-predict ways due to new introductions and complex interactions between 'bug' species and climatic change.

This hard-to-predict (or model) change makes it tempting to set this issue aside and just concentrate on more tractable factors like precipitation or temperature, but I believe this is a mistake, for two reasons:

1. Those 'bug' interactions have significant effects on the impact of climate change - if a tree is under one stress, it is generally more affected by other kinds of stress. The biotic and abiotic interactions simply cannot be modelled separately.

2. If the biotic issues are so important, but hard-to-predict, any results that we produce from only considering the abiotic stresses are likely to be misleading, and lead us towards giving faulty advice.

In the western US, the Pine bark beetle is killing most of the pine tree forests that

cover the mountains and help prevent erosion, and keep the snow there longer.

In the Eastern US, the white nose syndrome is killing the bats by the millions,

so we can expect a huge increase in mosquitoes, which should lead to

blood brone pathogens decimating populations, including humans.

In Alaska the tree line has moved up in elevation by over 500 feet.

In Wyoming and Montana, the forests are encroaching and taking over

meadows that formerly would not sustain trees.

In Kansas the scrub trees are moving westward across the state at about

one mile per year.

Take a look at some of the work of Dr. Richard Waring, who has tackled this question repeatedly in research to predict forest type responses to climate change in North America:

http://www.fsl.orst.edu/~waring/Publications/Publications.htm

Dick's research collaborator Dr. Steve Running and his Numerical Terradynamics Simulation Group builds out scenarios of forest response to climate changes in terms of both tree adaptation and its effect on ecosystem processes:

http://www.ntsg.umt.edu/user/9/biblio

I should also have mentioned Dr. Ron Neilson who has worked for many years on this specific question of how vegetation of various kinds dynamically responds to climate forcing (Ron works in arid and semiarid as well as more forested lanscapes, and he connects plant physiological responses to vegetative and ecosystem-level change): http://www.fs.fed.us/pnw/mdr/mapss/contact/cv/ron.shtml

There are many paleoreconstruction works on this topic.

The aditional issue. We carried out study near Tver (Russia). There were several points with different times after deforestation. On each point the type of plants (forest) showed a consecutive change. The 80-year point after deforestation was absolutly identical with a typical forest in current climate zone.

So it is possible to say, that 80 years is a lag-time for stubilisation in current conditions,

Dear Mikhail,

thank you for the useful informations. Can you mention a paper about the study?

Sincerly

Dear Christopher,

i also thank you very much. I've some papers from Dr. Waring and Dr. Neilson. I guess, i' d suggest to build an international group to work on this topic. Due to climate change and its effects on vegetation migration, on biogeochemical cycles, it is absolutely necessary to consider the change of habitats of plants species or assosiations in out models. That'll be especially enormous important to predict the change of carbon assimilation as well as the nitrogen fixation under climate change in 2100. Who can/would/wish (to) collaborate in a such project?

Dear All,

I guess, i' d suggest to build an international group to work on this topic. Due to climate change and its effects on vegetation migration, on biogeochemical cycles, it is absolutely necessary to consider the change of habitats of plants species or assosiations in out models. That'll be especially enormous important to predict the change of carbon assimilation as well as the nitrogen fixation under climate change in 2100. Who can/would/wish (to) collaborate in a such project?

Dear Abdulla Sakalli

I can't find now this resalts published in english.

I will try to ask colleges,

About your promotion about an "international group" - sounds interesting.

Our field of study is soil surface and biodiersity evolution. We have spetial objects on the territory of MSU with "initial stages of soil formation under different type of plants".

It if more than 40 years old, The main focus of it - water fluxes, curbon cicles and biogeochemistry. My main interest is biogeochemistry and microbiology.

Abdulla: Hello, while vegetation change isn't my field directly, so I'm not likely to be a core member of such a group, I'm interested because it's an integral part of how ecosystems and watershed processes respond to climate forcing. I think the researchers I mentioned in the previous post each have at least one or two collaborators with a specific interest in dynamic processes of vegetation change.

By the way in searching just a little on this subject I found a paleo-botanical reconstruction paper that seems to provide some interesting perspective:

http://www.stri.si.edu/sites/publications/PDFs/STRI-W_Jaramillo_2012_Correa_Metrio2012_PetenEscobar.pdf

I know there is quite a bit more recent literature on this subject, and a group of North and South American and Australian researchers, including paleoecologists, is presently working on it from the perspective of wildfire-mediated vegetation change (I believe the director is Dr. Cathy Whitlock, Montana State University - http://www.wildfirepire.org/team/cathy-whitlock)

An interesting side note to climate change can be inferred from the study of cave formations where climate change in one location can have equal and opposite effects at different Latitudes due to changes in Jet streams.

A look at FORT STANTON CAVE STUDY PROJECT will be of interest here as they cored a cave formation to get a 45,000 year sample of climate change at

Fort Stanton Cave, Lincoln County, New Mexico.

A similar thing was done at HULU China. The climate changes were mirror

images of one another.

Google Images the following: Fort Stanton Cave Snow River for some interesting pictures of one of the worlds longest single cave formations.

Climate change is very much about changes in Rainfall and snowfall patterns

over very long time periods which are in turn caused by changes in Jet Streams

Dear Mikhail,

i'm glad to read that you've interest in a collaboration. My main interest is also in biogechemical cycles, vegetation modelling, phenology, plant distribution and carbon-nitrogen cycles interaction. I also highly motivated to study the climate-vegetation interactions. If we can get some people together, we can start to change information, how we can call a international group together.

Dear Christopher,

you're still very welcome to the conversation. It's absolutely no problem to be not a vegetation researcher. We need every ideas and suggestions. I thank you very much for the very useful informations. Indeed, the alnus distribution could very interested for you, because the most alnus species occur along rivers and streams. A change on the water contents of the soil may influenced the occurrence of the species enormously.

Yes I'm a big fan of Alnus!