consider removing some hypotheses

[teixeirak]

@mcgregorian1 , based on coauthor feedback, particularly Lawren's, I wonder if we should remove some of the hypotheses. This could simplify the story. Here are the ones I think we could drop and the logic:

• H2.2- First, see logic for dropping 2.3. If we drop 2.3, 2.2 becomes unnecessary. Note that 2.2 isn't associated with any really meaningful/ interesting results. We could simplify figure 2 (remove panels e & f).
• H2.3- Lawren thought this was a funny hypothesis because some traits must interact with the tree height effect, just not the ones we looked at. He's correct that there are many relevant traits, and some must play a role here. Another point is that we're not testing differences in height within species--just differences across species. Really what we're testing is whether trees with more drought-sensitive traits dominate the canopy. If we keep this hypothesis, we need to work on some language to clarify. Note that dropping 2.2 and 2.3 would allow us to simplify numbering under H2 so that we don't have 2.1a, 2.1b, etc. (Lawren objected even to decimal numbered hypotheses! Not sure he noticed this...)
• H3.1- Lawren found this funny in that there must be some differences-- they're just not statistically significant. I also find it funny in that its not a scientifically interesting hypothesis (not pointing to general mechanisms, just describing our droughts).
• H3.2 and 3.3 ??? - I think I'd lean more towards keeping these in, but they may not require formal presentation in the hypothesis table.

Please advise what you'd like to do as soon as you can, as this really affects the structuring of the paper and should be resolved before we do much more.

[mcgregorian1]

• H2.2- First, see logic for dropping 2.3. If we drop 2.3, 2.2 becomes unnecessary. Note that 2.2 isn't associated with any really meaningful/ interesting results. We could simplify figure 2 (remove panels e & f).
• H2.3- Lawren thought this was a funny hypothesis because some traits must interact with the tree height effect, just not the ones we looked at. He's correct that there are many relevant traits, and some must play a role here. Another point is that we're not testing differences in height within species--just differences across species. Really what we're testing is whether trees with more drought-sensitive traits dominate the canopy. If we keep this hypothesis, we need to work on some language to clarify. Note that dropping 2.2 and 2.3 would allow us to simplify numbering under H2 so that we don't have 2.1a, 2.1b, etc. (Lawren objected even to decimal numbered hypotheses! Not sure he noticed this...)

Hmm. Really what we're asking here is should we change H2 completely to only be focusing on how species traits predict drought resistance (H2.1), which to be fair is one of the main foci of the paper. I think in that context, it does make sense to drop H2.3/H2.2

• However, I don't think it makes sense to fully get rid of the interaction with height that we're looking at within H2.2. I'm not sure keeping it means that it warrants having its own separate Hypothesis, but I still think it's interesting to note, and it gives another clue to the whole picture. I think the important thing here is that if we keep it we should specify that there are of course other traits affecting drought resistance and interacting with height, but we wanted to test these specific ones with height based on what we found for 2.1. Does that make sense?

[mcgregorian1]

• H3.1- Lawren found this funny in that there must be some differences-- they're just not statistically significant. I also find it funny in that its not a scientifically interesting hypothesis (not pointing to general mechanisms, just describing our droughts).
• H3.2 and 3.3 ??? - I think I'd lean more towards keeping these in, but they may not require formal presentation in the hypothesis table.

I agree with you on 3.2 and 3.3 - they definitely should be mentioned in the discussion/results, but I don't think they necessarily need to be their own hypotheses.

True for 3.1 also. I'm wondering if all of Hypothesis 3 should be a section in the discussion, and then we can give a small reflection on what these mean in relation to the quantified results?

[mcgregorian1]

I think in general if we want to follow Lawren's dislike of decimals for the hypotheses, then we should do a formatting restructure. Assuming we keep 1.0,1.1,1.2,1.3,2.1, and 2.2, I was thinking it could look something like this:

Hypothesis 1: Larger, taller trees are more susceptible to drought

• H1a. Rt decreases with stem diameter
• H1b. Rt decreases with height
• H1c. Dominant trees have lowest Rt, even with correcting for height
  • we'd have to do some finegling here with how to present the resulst for this one in Table 1
• H1d. There is a negative interactive effect between height and TWI

Hypothesis 2: Species traits predict drought resistance

• H2a. Wood density correlates negatively to Rt
• H2b. LMA correlates positively
• H2c. RP have higher Rt than diffuse/semi-ring
• H2d. PLA correlates negatively
• H2e. TLP correlates negatively

Originally I was going to put the original 2.2 here but the more I look at it the more I agree that it doesn't necessarily fit. If anything, it could be like a mini-hypothesis at the end, such that the narrative would go like this:

• we first investigated the extent to which taller trees are more susceptible to drought by looking at DBH, height, canopy position, and TWI. We confirmed our hypothesis that Rt reflects this greater susceptibility for taller trees, then we wanted to see how certain species traits played a role in determining Rt (e.g. by looking at the coefficients).
  • then, in Discussion or something? Or we put it as an aside for H2 so that way it doesn't come out the blue?
  • Once we had the effects of height/larger trees plus species traits on Rt, we were curious if over a community mean, the tested species traits would interact specifically with height to yield the same kind of effect. In other words, we were curious if height's role in determining drought resistance could be a proxy for understanding how these traits change with height.
  • So basically, we know that taller trees are more susceptible, and we know how each of the species traits relates to Rt. Thus, if we have a lower Rt with height, and we have a lower Rt for the traits, then presumably if we compare the traits with height we can get a kind of comparison that holds true. (I recognize this would mean rethinking the results a bit in terms of how we interpret this)

What do you think?

[teixeirak]

I like this new set of hypotheses; let's start implementing.

Regarding the original 2.2, I think it was originally an interesting question but turned out to be something of a non-story. I think we should mention it briefly in the results and discussion (if appropriate), but it shouldn't go in the hypothesis table.

[teixeirak]

@mcgregorian1, I've started working on the table. I'm finding that I don't like condensing all of the size/microenvironment hypotheses into one. See what you think....

[mcgregorian1]

I like this new set of hypotheses; let's start implementing.

Regarding the original 2.2, I think it was originally an interesting question but turned out to be something of a non-story. I think we should mention it briefly in the results and discussion (if appropriate), but it shouldn't go in the hypothesis table.

ok, sounds good!

[mcgregorian1]

@teixeirak I'm looking at what you're saying about them not fitting and I'm coming up with 2 options.

1. We change H1 to be "Tree height is the primary biophysical variable affecting drought resistance", which means we'd have to include mention of our tests for elevation at some point (either as a separate test (i.e. 1d) or embedded within our existing ones).

2. We include 1c as part of 1b. I think we could make a logical jump and say this for 1b: if we predict that trees with more exposed crowns have lower Rt, then smaller trees - especially those in drier microhabitats given the elevational gradient apparent in the plot - will have higher resistance even in drier microhabitats.

   • this is opposite what we currently have for 1c, however. What was our initial reasoning for predicting that smaller trees in drier areas would be less resistant? I thought we had found a paper saying smaller trees (S) had higher resistance overall. I'm not seeing it in our introduction.

For reference in case we need to refer to them, here are the original hypotheses

[teixeirak]

@mcgregorian1, I've updated/ simplified the table, and I think it's greatly improved. Closing this--at least for now.

[mcgregorian1]

Ok thank you! I can look at this hopefully soon