Victor's notebook - vvandermeersch/climategrowthshifts GitHub Wiki
See also: Lizzie's lit review and Lit on missing rings
July 28
Some quotes from Mike:
phi is really more “probability of concordant shock in stand” rather than “probability of stand-level shock”, right?
phi and omega are fine with sufficiently informative subscripts. I think it would be helpful to explicitly use “tree” when for the omega, to make the stand/tree progression more obvious. You can always be super explicit, p( tree_shock | stand concordance ) * p( stand concordance ) or even phi_{stand concordance} * omega_{tree_shock | stand concordance } The trick is making that more compact. Maybe phi_{sc} * omega_{ts sc)? For the more detailed derivations I think it’s fine to use separate greek letters, such as p( tree_shock | stand concordance ) -> omega p( tree_shock | not stand concordance ) -> rho p( stand concordance ) -> phi, to keep the equations from being too ungainly.
Because you all are the ecologists you will have the final word, but in my understanding p(z_s = 1) is really capturing the environment of a stand — cold snaps, storms, even things like volcanic eruptions spewing ash that block the sun — and so doesn’t have anything to do with species biology and should be independent of species. On the other hand p(z_t = 1 | z_s = 1) captures a tree's response to that environment and so variation by species seems reasonable.
Sept. 30
Jotting down some ideas!
| Milestone | Question | Previous literature |
|---|---|---|
| Multi-species assessment and carbon | Do we see evidence for major impacts of climate change on tree growth and multi-decadal capture of carbon, since 1980s? What species seem the most disrupted, and how it can reshift species-specific contribution to carbon cycle in the coming decades? (Multi-species mitigation or global disruption?) | |
| Multi-species assessment and carbon | What causes growth patterns? Is it more species differences in climatic sensitivity, or is it more spatial variation of climate? Is it possible to disentangle both aspects? Like, is this region growing less because the local species pool is more sensitive or because the climate is harsher? (but maybe the less sensitive species are in harsher climate?) | |
| Multi-species assessment and carbon | Related to previous question... what is climate sensitivity, and how it varies across climates? Is a species more sensitive to both bad and good conditions? Were sensitive species in a "soft" climates until now, so they were able to take the most out of a good year? Or, is there an evident trade-off between harsh/soft conditions and low/high sensitivity, and is it going to be disrupt? | |
| Multi-species assessment and carbon | Also kind of related to previous question... Can we separate the impact of magnitude and timing of climate variations, across species? Like, across the region studied, what are the areas where the growth is mostly disrupted by one specific predictor (like soil moisture, related to timing=winter, or VPD related to timing=summer!), or is there a coherent signal across predictors everywhere (less winter prec., more summer drought=you then don't care about timing, only about magnitude?) | St. George & Ault (2014) |
| Multi-species assessment and carbon | What is the contribution of known climatic drivers (the predictors we picked) on the growth trends of the last decades? As compared to the contribution of stand-level GPs? And are the stand-level GPs capturing something that still make sense? Like something with coherent with climate (drier sites more impacted or whaetever) , but that is not captured by our yearly predictors? So, to what extent are we able to understand the growth trend of the last decades? (look also at the contribution of tree-level GPs) | |
| Growth niche and functional traits 🌎 | Do we observe a coherent shift in growth niche across species (like northward for everyone?), and how important it is as compared to potential range shift? (is growth niche shift faster than range shift?) And so, are the different species in the same forest/area all impacted by climate change the same way? Or, within the current pool of local species, is climate change favoring some species? Or are they all f*****? | - |
| Growth niche and functional traits 🌎 | Are climate change impacts different across the functional trait space? Are some traits consistently associated with lower sensitivity to climate? | - |
Major challenge:
How to articulate well spatial inference between milestones?
Example: mitigation of carbon capture, maybe some species are not doing too bad, or not everywhere = more growth and carbon assimilation in part of their current range... Wait is this still multi-species carbon assessment or is still already growth niche milestone?
Outside current milestones:
- growth-mortality associations: are growth reductions associated with increased mortality? (we would need mortality data! Next meta-analysis?)