relate cues to budburst timing

[lizzieinvancouver]

We want to test if bigger cues relate to later leafout ... so:

• [x] Pull leafout dates from PEP725 (maybe just Germany or whatever dataset we used in the BB ms) and compare to cues estimated from a basic pheno-only model.
• [ ] Ditto for HF species
• [x] Maybe try using the natural units model and see how much of the variation in predicted leafout day is due to the cues (versus intercept) for 14 hour days, 20 C and high chill....

@DeirdreLoughnan @lizzieinvancouver and @FaithJones will work on this, but we may ask for help from @cchambe12 and @AileneKane

[lizzieinvancouver]

I tried the natural cues model, see commit 9f80d76133827fda2cc132813d282c4d1fa2c5e1 for that. I also sifted through my PEP725 data ... but it would take a bit of work to get usable data (I found one site with 7 species ... which PEP says is in Africa ... which is weird). But the natural cues work actually reminded me that @dflynn-volpe and I went through this all before!

Check out Figure S1 in that paper or this quote:

Across-species responses to forcing and photoperiod were related for budburst (mean slope of 0.31, CI of 0.15–0.48) and leafout (mean slope of 0.45, CI of 0.26–0.66), whereas responses between forcing and chilling were only weakly related (budburst: mean slope of 0.12, CI of 0.04–0.20; leafout: mean slope of 0.11, CI of 0.04–0.20). Early species tended to show the smallest responses to all cues, suggest- ing they burst bud and unfurl leaves early because they require lower amounts of spring forcing and winter chilling, and shorter days to start growth each season. By contrast, mid and late species relied on a varying mix of cues to drive their spring phenology: for example, P. grandidentata showed a relatively strong response to forcing and chilling, but a milder response to photoperiod, whereas Fagus grandifolia had a strong response to forcing and photoperiod, and a much smaller response to chilling.

Laube et al. 2014 also does a little of this, but gets sometimes hard to follow results since she also had WAY low chill treatments (@cchambe12 discusses this in one of her cutting papers, as she did not find shifting leafout order .. indeed we may also want to cite Chamberlain & Wolkovich 2021 for that point perhaps? Though I like to keep self-citation down, so we could just do Flynn & Wolkovich).

My take-home is we should pull ourselves out of this rabbit hole and cite the literature so I am closing this issue.

My only other take-home, is that Laube et al. 2014 discusses successional strategy so maybe worth a re-read by us all, as I think that could go with the hypotheses also.