9 Terminal shoot analyses

9.1 Goals

Does severing affect the number and size of active, independent rhizome systems?

There are two components of this:

  1. how does severing affect the number of plants that produce 0, 1, or 2 systems? Approach: contingency table analysis. For each treatment (C, S1, S2, S4), we want to see how many plants had 0, 1, or 2 systems, and compare those counts.

KE thoughts July 14: I think this still makes sense to do. It addresses the question, and this type of analysis doesn’t feel repetitive with other things, because we haven’t been counting systems for the other questions.

  1. how does severing affect the size of plants that produce 0, 1, or 2 systems? Approach: modeling total leaf area as a function of severing (C, S1, S2, S4), number of systems (0, 1, 2), and their interaction. I know previously we had been talking about breaking the controls out as a separate group. However, I think if we do it this way, it will be more parallel with the contingency table analysis, and lets us test for that interaction, because now our controls won’t be synonymous with both a treatment and a number of systems.

KE thoughts July 14: For this piece, I think working with the zero systems doesn’t make a lot of sense, because they have zero leaf area by definition, and so contrasts with the other categories aren’t super meaningful in general, and also do not vary across the severing treatments, which is the point of this. In the contingency table analysis described above, we can look at how the distribution of the zero systems may vary across the severing treatments. I think the comparisons that are valuable are, within a severing treatment, do systems have different total or average leaf areas when they have a front vs. a back vs. both system components? Putting aside the control treatment, I think for the three types of severing, we should definitely be able to compare front to both. Comparisons involving the back are likely to be non-significant because of the small sample sizes.

So, continuing to think this through, maybe for this portion, comparisons that would be interesting are: control vs. any type of severing for front, back, and both (in reality, this will probably only end up working for the front), and then within s1, s2, and s4, are there differences between front, back, or both? I recognize the first piece is somewhat repetitive with previous analyses of front leaf area, but I think it makes sense to be to present it that way in this context.

Then, what remains to be seen is whether total or average leaf area is a better way of addressing our question. Given the word “independent” in the question above, I think that suggests that we’d want to focus on average leaf area, but I still think that we want to include total leaf area (perhaps as inset plots) because I think it’s helpful to have that visualization.

Both of these analyses can be performed with both the 1991 data and the 1992 data.

A potential extension is incorporating branch number. A simple way to do this would be to use branch number in place of the number of systems. So, in piece a., we would be looking at severing across branch numbers, and for piece b., we would be looking at leaf area as a function of severing, number of branches, and their interaction. I think a potential issue for this is that the contingency table for severing treatment x branch number would be quite large. Another option could be to add branching number as a covariate in the model of leaf area, in addition to the system number x severing treatment interaction.

9.3 1991 with 0-1-2

9.3.1 1991 tables

A table of system status (One = front system or back only, Two = front & back, None = dead (no front, no back)) first in total, and then across the treatments:

Status N
None 41
One 291
Two 117

Most systems have only one system.

Sever Status N
C None 7
C One 123
C Two 1
S1 None 15
S1 One 27
S1 Two 52
S2 None 8
S2 One 50
S2 Two 45
S4 None 11
S4 One 91
S4 Two 19

9.3.2 1991 contingency table analysis:

## 
##  Pearson's Chi-squared test
## 
## data:  mayappleData91$Status and mayappleData91$Sever
## X-squared = 129.59, df = 6, p-value < 2.2e-16
##                      mayappleData91$Sever
## mayappleData91$Status   C  S1  S2  S4
##                  None   7  15   8  11
##                  One  123  27  50  91
##                  Two    1  52  45  19
##                      mayappleData91$Sever
## mayappleData91$Status        C        S1        S2       S4
##                  None 11.96214  8.583519  9.405345 11.04900
##                  One  84.90200 60.922049 66.755011 78.42094
##                  Two  34.13586 24.494432 26.839644 31.53007
##                      mayappleData91$Sever
## mayappleData91$Status           C          S1          S2          S4
##                  None -1.43471104  2.19010145 -0.45824280 -0.01474059
##                  One   4.13469192 -4.34605108 -2.05070308  1.42047089
##                  Two  -5.67143299  5.55759544  3.50538717 -2.23146943

9.3.3 1991 leaf area analysis per system

## Type III Analysis of Variance Table with Satterthwaite's method
##              Sum Sq Mean Sq NumDF  DenDF F value   Pr(>F)   
## Status       327401  327401     1 391.79  7.3313 0.007073 **
## Sever        285397   95132     3 391.44  2.1302 0.095888 . 
## Status:Sever 534833  178278     3 393.68  3.9921 0.008054 **
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## $emmeans
##  Status emmean   SE    df lower.CL upper.CL
##  One       487 17.6  66.5      452      522
##  Two       330 56.9 396.3      219      442
## 
## Results are averaged over the levels of: Sever 
## Degrees-of-freedom method: satterthwaite 
## Confidence level used: 0.95 
## 
## $contrasts
##  contrast  estimate   SE  df t.ratio p.value
##  One - Two      157 57.9 392 2.708   0.0071 
## 
## Results are averaged over the levels of: Sever 
## Degrees-of-freedom method: satterthwaite
## $emmeans
## Status = One:
##  Sever emmean    SE  df lower.CL upper.CL
##  C        637  21.4 135      595      679
##  S1       336  42.7 356      252      420
##  S2       438  31.7 300      376      501
##  S4       537  24.3 186      489      585
## 
## Status = Two:
##  Sever emmean    SE  df lower.CL upper.CL
##  C        210 214.8 395     -212      632
##  S1       370  31.4 274      308      432
##  S2       392  33.5 303      326      458
##  S4       349  50.2 386      250      448
## 
## Degrees-of-freedom method: satterthwaite 
## Confidence level used: 0.95 
## 
## $contrasts
## Status = One:
##  contrast estimate    SE  df t.ratio p.value
##  C - S1      300.6  45.8 397  6.570  <.0001 
##  C - S2      198.5  35.8 392  5.538  <.0001 
##  C - S4       99.5  29.4 386  3.380  0.0044 
##  S1 - S2    -102.1  51.3 395 -1.992  0.1929 
##  S1 - S4    -201.2  47.3 398 -4.257  0.0002 
##  S2 - S4     -99.1  37.6 390 -2.637  0.0430 
## 
## Status = Two:
##  contrast estimate    SE  df t.ratio p.value
##  C - S1     -160.1 216.7 394 -0.739  0.8815 
##  C - S2     -181.7 217.2 395 -0.837  0.8369 
##  C - S4     -139.0 220.4 395 -0.631  0.9222 
##  S1 - S2     -21.7  43.5 391 -0.498  0.9595 
##  S1 - S4      21.1  57.0 385  0.370  0.9827 
##  S2 - S4      42.8  58.4 389  0.732  0.8840 
## 
## Degrees-of-freedom method: satterthwaite 
## P value adjustment: tukey method for comparing a family of 4 estimates
## $emmeans
## Sever = C:
##  Status emmean    SE  df lower.CL upper.CL
##  One       637  21.4 135      595      679
##  Two       210 214.8 395     -212      632
## 
## Sever = S1:
##  Status emmean    SE  df lower.CL upper.CL
##  One       336  42.7 356      252      420
##  Two       370  31.4 274      308      432
## 
## Sever = S2:
##  Status emmean    SE  df lower.CL upper.CL
##  One       438  31.7 300      376      501
##  Two       392  33.5 303      326      458
## 
## Sever = S4:
##  Status emmean    SE  df lower.CL upper.CL
##  One       537  24.3 186      489      585
##  Two       349  50.2 386      250      448
## 
## Degrees-of-freedom method: satterthwaite 
## Confidence level used: 0.95 
## 
## $contrasts
## Sever = C:
##  contrast  estimate    SE  df t.ratio p.value
##  One - Two    426.6 215.5 394  1.980  0.0484 
## 
## Sever = S1:
##  contrast  estimate    SE  df t.ratio p.value
##  One - Two    -34.1  51.5 400 -0.662  0.5083 
## 
## Sever = S2:
##  contrast  estimate    SE  df t.ratio p.value
##  One - Two     46.3  44.4 399  1.044  0.2971 
## 
## Sever = S4:
##  contrast  estimate    SE  df t.ratio p.value
##  One - Two    188.2  54.3 397  3.465  0.0006 
## 
## Degrees-of-freedom method: satterthwaite

9.4 1992 with 0-1-2

9.4.1 1992 tables

A table of system status (One = front system or back only, Two = front & back, None = dead (no front, no back)) first in total, and then across the treatments:

Status N
None 19
One 120
Two 83

Most systems have only one system.

Sever Status N
C None 5
C One 62
S1 None 5
S1 One 12
S1 Two 29
S2 None 1
S2 One 15
S2 Two 34
S4 None 8
S4 One 31
S4 Two 20

9.4.2 1992 contingency table analysis:

## 
##  Pearson's Chi-squared test
## 
## data:  mayappleData92$Status and mayappleData92$Sever
## X-squared = 80.881, df = 6, p-value = 2.35e-15
##                      mayappleData92$Sever
## mayappleData92$Status  C S1 S2 S4
##                  None  5  5  1  8
##                  One  62 12 15 31
##                  Two   0 29 34 20
##                      mayappleData92$Sever
## mayappleData92$Status         C        S1        S2       S4
##                  None  5.734234  3.936937  4.279279  5.04955
##                  One  36.216216 24.864865 27.027027 31.89189
##                  Two  25.049550 17.198198 18.693694 22.05856
##                      mayappleData92$Sever
## mayappleData92$Status          C         S1         S2         S4
##                  None -0.3066175  0.5357717 -1.5852329  1.3129918
##                  One   4.2844503 -2.5799553 -2.3134448 -0.1579327
##                  Two  -5.0049525  2.8458162  3.5401596 -0.4383032

9.4.3 1992 leaf area analysis per system

## Type III Analysis of Variance Table with Satterthwaite's method
##               Sum Sq Mean Sq NumDF  DenDF F value    Pr(>F)    
## Status        310937  310937     1 195.94  7.1938   0.00794 ** 
## Sever        1344753  448251     3 190.22 10.3707 2.362e-06 ***
## Status:Sever  327411  163705     2 193.12  3.7875   0.02435 *  
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## $emmeans
##  Status emmean   SE   df lower.CL upper.CL
##  One       516 29.6 33.3      456      576
##  Two    nonEst   NA   NA       NA       NA
## 
## Results are averaged over the levels of: Sever 
## Degrees-of-freedom method: satterthwaite 
## Confidence level used: 0.95 
## 
## $contrasts
##  contrast  estimate SE df z.ratio p.value
##  One - Two   nonEst NA NA NA      NA     
## 
## Results are averaged over the levels of: Sever 
## Degrees-of-freedom method: satterthwaite
## $emmeans
## Status = One:
##  Sever emmean   SE    df lower.CL upper.CL
##  C        667 32.0  46.0      602      731
##  S1       307 65.4 158.2      178      436
##  S2       539 57.3 163.7      426      652
##  S4       551 41.7  99.2      468      634
## 
## Status = Two:
##  Sever emmean   SE    df lower.CL upper.CL
##  C     nonEst   NA    NA       NA       NA
##  S1       349 43.6  98.4      262      435
##  S2       403 40.3  88.0      323      483
##  S4       329 50.9 135.4      229      430
## 
## Degrees-of-freedom method: satterthwaite 
## Confidence level used: 0.95 
## 
## $contrasts
## Status = One:
##  contrast estimate   SE  df t.ratio p.value
##  C - S1      359.2 68.3 196  5.259  <.0001 
##  C - S2      127.9 60.7 190  2.107  0.1546 
##  C - S4      115.7 46.1 186  2.512  0.0613 
##  S1 - S2    -231.3 83.2 195 -2.781  0.0301 
##  S1 - S4    -243.5 73.6 196 -3.307  0.0061 
##  S2 - S4     -12.2 66.4 190 -0.184  0.9978 
## 
## Status = Two:
##  contrast estimate   SE  df t.ratio p.value
##  C - S1     nonEst   NA  NA     NA      NA 
##  C - S2     nonEst   NA  NA     NA      NA 
##  C - S4     nonEst   NA  NA     NA      NA 
##  S1 - S2     -54.0 53.1 188 -1.016  0.7404 
##  S1 - S4      19.4 60.9 186  0.319  0.9887 
##  S2 - S4      73.4 59.2 187  1.240  0.6020 
## 
## Degrees-of-freedom method: satterthwaite 
## P value adjustment: tukey method for comparing a family of 4 estimates
## $emmeans
## Sever = C:
##  Status emmean   SE    df lower.CL upper.CL
##  One       667 32.0  46.0      602      731
##  Two    nonEst   NA    NA       NA       NA
## 
## Sever = S1:
##  Status emmean   SE    df lower.CL upper.CL
##  One       307 65.4 158.2      178      436
##  Two       349 43.6  98.4      262      435
## 
## Sever = S2:
##  Status emmean   SE    df lower.CL upper.CL
##  One       539 57.3 163.7      426      652
##  Two       403 40.3  88.0      323      483
## 
## Sever = S4:
##  Status emmean   SE    df lower.CL upper.CL
##  One       551 41.7  99.2      468      634
##  Two       329 50.9 135.4      229      430
## 
## Degrees-of-freedom method: satterthwaite 
## Confidence level used: 0.95 
## 
## $contrasts
## Sever = C:
##  contrast  estimate   SE  df t.ratio p.value
##  One - Two   nonEst   NA  NA     NA      NA 
## 
## Sever = S1:
##  contrast  estimate   SE  df t.ratio p.value
##  One - Two    -41.4 74.8 196 -0.554  0.5804 
## 
## Sever = S2:
##  contrast  estimate   SE  df t.ratio p.value
##  One - Two    135.9 65.3 189  2.082  0.0387 
## 
## Sever = S4:
##  contrast  estimate   SE  df t.ratio p.value
##  One - Two    221.5 61.3 193  3.615  0.0004 
## 
## Degrees-of-freedom method: satterthwaite

9.5 Manuscript plots with 0-1-2

For 1991, the leaf area in each year, with the total leaf area as an inset:

The same thing for 1992:

9.6 1991

9.6.1 1991 tables

A table of system status (Front = front system only, Back = back system only, Both = front & back, None = dead (no front, no back)) first in total, and then across the treatments:

Status N
Back 15
Both 117
Front 276

Summary: Most systems have only a front system. Having only a back system is rare across all treatments.

Sever Status N
C Both 1
C Front 123
S1 Back 7
S1 Both 52
S1 Front 20
S2 Back 6
S2 Both 45
S2 Front 44
S4 Back 2
S4 Both 19
S4 Front 89

Summary: Almost all control systems have front systems only. The majority of S1 systems have both systems. S2 systems are equally likely to have a front system or both systems. Most S4 systems only have a front system. Across the severing treatments, there were between 7 and 15 systems that were dead (e.g. zero front and zero back).

9.6.2 1991 contingency table analysis:

## 
##  Pearson's Chi-squared test
## 
## data:  mayappleData91$Status and mayappleData91$Sever
## X-squared = 149.75, df = 6, p-value < 2.2e-16
##                      mayappleData91$Sever
## mayappleData91$Status   C  S1  S2  S4
##                 Front 123  20  44  89
##                 Back    0   7   6   2
##                 Both    1  52  45  19
##                      mayappleData91$Sever
## mayappleData91$Status         C        S1        S2        S4
##                 Front 83.882353 53.441176 64.264706 74.411765
##                 Back   4.558824  2.904412  3.492647  4.044118
##                 Both  35.558824 22.654412 27.242647 31.544118
##                      mayappleData91$Sever
## mayappleData91$Status         C        S1        S2        S4
##                 Front  4.271077 -4.574499 -2.527866  1.691149
##                 Back  -2.135140  2.403185  1.341647 -1.016469
##                 Both  -5.795425  6.165473  3.402151 -2.233474

9.6.3 1991 total leaf area analysis

Note: This is somewhat challenging, because we don’t have any back-only controls, and we have just one control with both systems.

## Type III Analysis of Variance Table with Satterthwaite's method
##               Sum Sq Mean Sq NumDF  DenDF F value    Pr(>F)    
## Status        981778  490889     2 391.41  7.3160 0.0007597 ***
## Sever          88826   29609     3 387.99  0.4413 0.7236156    
## Status:Sever 1194568  238914     5 391.32  3.5606 0.0036793 ** 
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## $emmeans
##  Status emmean   SE  df lower.CL upper.CL
##  Front     481 23.3  81      434      527
##  Back   nonEst   NA  NA       NA       NA
##  Both      645 69.8 393      508      783
## 
## Results are averaged over the levels of: Sever 
## Degrees-of-freedom method: satterthwaite 
## Confidence level used: 0.95 
## 
## $contrasts
##  contrast     estimate   SE  df t.ratio p.value
##  Front - Back   nonEst   NA  NA     NA      NA 
##  Front - Both     -165 71.5 389 -2.302  0.0567 
##  Back - Both    nonEst   NA  NA     NA      NA 
## 
## Results are averaged over the levels of: Sever 
## Degrees-of-freedom method: satterthwaite 
## P value adjustment: tukey method for comparing a family of 3 estimates
## $emmeans
## Status = Front:
##  Sever emmean    SE  df lower.CL upper.CL
##  C        637  26.3 131      585      689
##  S1       294  60.8 364      175      414
##  S2       445  41.2 317      364      526
##  S4       547  30.1 186      487      606
## 
## Status = Back:
##  Sever emmean    SE  df lower.CL upper.CL
##  C     nonEst    NA  NA       NA       NA
##  S1       451 100.4 397      254      648
##  S2       380 108.4 397      166      593
##  S4       189 186.3 393     -178      555
## 
## Status = Both:
##  Sever emmean    SE  df lower.CL upper.CL
##  C        345 263.4 392     -173      863
##  S1       744  38.6 269      668      820
##  S2       788  41.1 298      708      869
##  S4       704  61.6 383      583      825
## 
## Degrees-of-freedom method: satterthwaite 
## Confidence level used: 0.95 
## 
## $contrasts
## Status = Front:
##  contrast estimate    SE  df t.ratio p.value
##  C - S1      342.8  63.9 396  5.362  <.0001 
##  C - S2      191.8  46.0 388  4.168  0.0002 
##  C - S4       90.3  36.3 382  2.487  0.0636 
##  S1 - S2    -150.9  71.5 396 -2.111  0.1512 
##  S1 - S4    -252.5  65.8 397 -3.839  0.0008 
##  S2 - S4    -101.6  48.2 386 -2.107  0.1527 
## 
## Status = Back:
##  contrast estimate    SE  df t.ratio p.value
##  C - S1     nonEst    NA  NA     NA      NA 
##  C - S2     nonEst    NA  NA     NA      NA 
##  C - S4     nonEst    NA  NA     NA      NA 
##  S1 - S2      71.3 146.5 392  0.487  0.9620 
##  S1 - S4     262.3 210.5 389  1.246  0.5980 
##  S2 - S4     191.0 214.4 389  0.891  0.8095 
## 
## Status = Both:
##  contrast estimate    SE  df t.ratio p.value
##  C - S1     -398.7 265.8 391 -1.500  0.4385 
##  C - S2     -443.1 266.3 392 -1.664  0.3443 
##  C - S4     -358.7 270.3 392 -1.327  0.5461 
##  S1 - S2     -44.5  53.3 388 -0.834  0.8384 
##  S1 - S4      40.0  69.9 382  0.572  0.9405 
##  S2 - S4      84.4  71.6 386  1.179  0.6403 
## 
## Degrees-of-freedom method: satterthwaite 
## P value adjustment: tukey method for comparing a family of 4 estimates

Both systems have marginally more leaf area than Front systems.

9.6.4 1991 leaf area analysis per system

## Type III Analysis of Variance Table with Satterthwaite's method
##              Sum Sq Mean Sq NumDF  DenDF F value   Pr(>F)   
## Status       339007  169503     2 391.75  3.8475 0.022144 * 
## Sever         41595   13865     3 388.44  0.3147 0.814745   
## Status:Sever 897745  179549     5 391.72  4.0755 0.001282 **
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## $emmeans
##  Status emmean   SE    df lower.CL upper.CL
##  Front     480 18.7  82.9      443      517
##  Back   nonEst   NA    NA       NA       NA
##  Both      328 56.5 393.1      217      439
## 
## Results are averaged over the levels of: Sever 
## Degrees-of-freedom method: satterthwaite 
## Confidence level used: 0.95 
## 
## $contrasts
##  contrast     estimate   SE  df t.ratio p.value
##  Front - Back   nonEst   NA  NA    NA       NA 
##  Front - Both      152 57.9 390 2.627   0.0243 
##  Back - Both    nonEst   NA  NA    NA       NA 
## 
## Results are averaged over the levels of: Sever 
## Degrees-of-freedom method: satterthwaite 
## P value adjustment: tukey method for comparing a family of 3 estimates
## $emmeans
## Status = Front:
##  Sever emmean    SE  df lower.CL upper.CL
##  C        637  21.2 135      595      679
##  S1       292  49.1 365      195      388
##  S2       445  33.3 320      380      511
##  S4       545  24.3 191      497      593
## 
## Status = Back:
##  Sever emmean    SE  df lower.CL upper.CL
##  C     nonEst    NA  NA       NA       NA
##  S1       451  81.3 397      291      611
##  S2       386  87.8 397      213      558
##  S4       180 150.8 393     -117      476
## 
## Status = Both:
##  Sever emmean    SE  df lower.CL upper.CL
##  C        198 213.3 393     -221      618
##  S1       371  31.1 273      309      432
##  S2       392  33.2 301      327      457
##  S4       349  49.9 384      251      447
## 
## Degrees-of-freedom method: satterthwaite 
## Confidence level used: 0.95 
## 
## $contrasts
## Status = Front:
##  contrast estimate    SE  df t.ratio p.value
##  C - S1      345.1  51.8 396  6.669  <.0001 
##  C - S2      191.3  37.3 388  5.132  <.0001 
##  C - S4       91.5  29.4 383  3.113  0.0107 
##  S1 - S2    -153.8  57.9 396 -2.658  0.0406 
##  S1 - S4    -253.6  53.2 397 -4.763  <.0001 
##  S2 - S4     -99.8  39.0 387 -2.555  0.0534 
## 
## Status = Back:
##  contrast estimate    SE  df t.ratio p.value
##  C - S1     nonEst    NA  NA     NA      NA 
##  C - S2     nonEst    NA  NA     NA      NA 
##  C - S4     nonEst    NA  NA     NA      NA 
##  S1 - S2      65.7 118.7 393  0.553  0.9456 
##  S1 - S4     271.3 170.5 390  1.591  0.3848 
##  S2 - S4     205.7 173.6 389  1.185  0.6369 
## 
## Status = Both:
##  contrast estimate    SE  df t.ratio p.value
##  C - S1     -172.3 215.3 392 -0.800  0.8542 
##  C - S2     -193.5 215.7 392 -0.897  0.8062 
##  C - S4     -151.1 218.9 392 -0.690  0.9007 
##  S1 - S2     -21.3  43.2 388 -0.492  0.9608 
##  S1 - S4      21.2  56.6 383  0.374  0.9822 
##  S2 - S4      42.4  58.0 386  0.732  0.8844 
## 
## Degrees-of-freedom method: satterthwaite 
## P value adjustment: tukey method for comparing a family of 4 estimates
## $emmeans
## Sever = C:
##  Status emmean    SE  df lower.CL upper.CL
##  Front     637  21.2 135      595      679
##  Back   nonEst    NA  NA       NA       NA
##  Both      198 213.3 393     -221      618
## 
## Sever = S1:
##  Status emmean    SE  df lower.CL upper.CL
##  Front     292  49.1 365      195      388
##  Back      451  81.3 397      291      611
##  Both      371  31.1 273      309      432
## 
## Sever = S2:
##  Status emmean    SE  df lower.CL upper.CL
##  Front     445  33.3 320      380      511
##  Back      386  87.8 397      213      558
##  Both      392  33.2 301      327      457
## 
## Sever = S4:
##  Status emmean    SE  df lower.CL upper.CL
##  Front     545  24.3 191      497      593
##  Back      180 150.8 393     -117      476
##  Both      349  49.9 384      251      447
## 
## Degrees-of-freedom method: satterthwaite 
## Confidence level used: 0.95 
## 
## $contrasts
## Sever = C:
##  contrast     estimate    SE  df t.ratio p.value
##  Front - Back   nonEst    NA  NA     NA      NA 
##  Front - Both   438.38 214.0 392  2.049  0.1022 
##  Back - Both    nonEst    NA  NA     NA      NA 
## 
## Sever = S1:
##  contrast     estimate    SE  df t.ratio p.value
##  Front - Back  -159.61  94.3 396 -1.693  0.2090 
##  Front - Both   -79.02  56.9 397 -1.390  0.3473 
##  Back - Both     80.59  86.2 396  0.935  0.6186 
## 
## Sever = S2:
##  contrast     estimate    SE  df t.ratio p.value
##  Front - Back    59.88  93.1 395  0.643  0.7962 
##  Front - Both    53.55  45.4 396  1.180  0.4661 
##  Back - Both     -6.34  93.2 396 -0.068  0.9975 
## 
## Sever = S4:
##  contrast     estimate    SE  df t.ratio p.value
##  Front - Back   365.33 152.2 390  2.400  0.0444 
##  Front - Both   195.74  54.0 394  3.625  0.0010 
##  Back - Both   -169.58 158.6 392 -1.069  0.5338 
## 
## Degrees-of-freedom method: satterthwaite 
## P value adjustment: tukey method for comparing a family of 3 estimates

So the average leaf area per system of Front systems is greater than the average leaf area per system of Both systems. This is probably driven by the higher leaf area of Front systems in the Control treatment.

9.7 1992

9.7.1 1992 tables

A table of system status (Front = front system only, Back = back system only, Both = front & back, None = dead (zero front, zero back)) first in total, and then across the treatments:

Status N
Back 3
Both 83
Front 117
Sever Status N
C Front 62
S1 Back 1
S1 Both 29
S1 Front 11
S2 Both 34
S2 Front 15
S4 Back 2
S4 Both 20
S4 Front 29

Summary: Control systems have front systems only (or no system). Having only a back system is rare across all treatments (N=3 total across the treatments). The majority of S1 systems have both systems. The majority of S2 systems have both systems. S4 systems are about equally likely to have a front system or both systems. Across the treatments, the number of dead (None) systems is relatively low and consistent (between 1 and 8 systems).

9.7.2 1992 contingency table analysis:

## 
##  Pearson's Chi-squared test
## 
## data:  mayappleData92$Status and mayappleData92$Sever
## X-squared = 80.28, df = 6, p-value = 3.127e-15
##                      mayappleData92$Sever
## mayappleData92$Status  C S1 S2 S4
##                 Front 62 11 15 29
##                 Back   0  1  0  2
##                 Both   0 29 34 20
##                      mayappleData92$Sever
## mayappleData92$Status          C         S1         S2         S4
##                 Front 35.7339901 23.6305419 28.2413793 29.3940887
##                 Back   0.9162562  0.6059113  0.7241379  0.7536946
##                 Both  25.3497537 16.7635468 20.0344828 20.8522167
##                      mayappleData92$Sever
## mayappleData92$Status           C          S1          S2          S4
##                 Front  4.39393215 -2.59827517 -2.49166857 -0.07268821
##                 Back  -0.95721270  0.50627842 -0.85096294  1.43557798
##                 Both  -5.03485389  2.98863307  3.12009601 -0.18662677

9.7.3 1992 total leaf area analysis

Note: Again, this is somewhat challenging, because of the very small number of back-only systems. Also there were no controls with both systems, and the number of None systems is very low in each severing treatment.

## Type III Analysis of Variance Table with Satterthwaite's method
##               Sum Sq Mean Sq NumDF  DenDF F value    Pr(>F)    
## Status       1906748  953374     2 190.03 15.4428 6.104e-07 ***
## Sever        1294318  431439     3 188.38  6.9885 0.0001754 ***
## Status:Sever  536345  178782     3 191.07  2.8959 0.0364339 *  
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## $emmeans
##  Status emmean   SE   df lower.CL upper.CL
##  Front     521 35.3 36.6      450      593
##  Back   nonEst   NA   NA       NA       NA
##  Both   nonEst   NA   NA       NA       NA
## 
## Results are averaged over the levels of: Sever 
## Degrees-of-freedom method: satterthwaite 
## Confidence level used: 0.95 
## 
## $contrasts
##  contrast     estimate SE df z.ratio p.value
##  Front - Back   nonEst NA NA NA      NA     
##  Front - Both   nonEst NA NA NA      NA     
##  Back - Both    nonEst NA NA NA      NA     
## 
## Results are averaged over the levels of: Sever 
## Degrees-of-freedom method: satterthwaite 
## P value adjustment: tukey method for comparing a family of 3 estimates
## $emmeans
## Sever = C:
##  Status emmean    SE    df lower.CL upper.CL
##  Front     667  37.6  48.5      591      742
##  Back   nonEst    NA    NA       NA       NA
##  Both   nonEst    NA    NA       NA       NA
## 
## Sever = S1:
##  Status emmean    SE    df lower.CL upper.CL
##  Front     302  81.1 159.8      142      463
##  Back      334 253.2 189.8     -166      833
##  Both      691  51.7 101.7      589      794
## 
## Sever = S2:
##  Status emmean    SE    df lower.CL upper.CL
##  Front     534  68.1 165.8      399      668
##  Back   nonEst    NA    NA       NA       NA
##  Both      798  47.7  92.2      703      893
## 
## Sever = S4:
##  Status emmean    SE    df lower.CL upper.CL
##  Front     582  50.8 110.0      481      683
##  Back      115 179.7 192.4     -240      469
##  Both      654  60.4 138.2      534      773
## 
## Degrees-of-freedom method: satterthwaite 
## Confidence level used: 0.95 
## 
## $contrasts
## Sever = C:
##  contrast     estimate    SE  df t.ratio p.value
##  Front - Back   nonEst    NA  NA     NA      NA 
##  Front - Both   nonEst    NA  NA     NA      NA 
##  Back - Both    nonEst    NA  NA     NA      NA 
## 
## Sever = S1:
##  contrast     estimate    SE  df t.ratio p.value
##  Front - Back    -31.6 264.2 188 -0.120  0.9921 
##  Front - Both   -388.9  92.4 193 -4.211  0.0001 
##  Back - Both    -357.3 256.4 187 -1.393  0.3464 
## 
## Sever = S2:
##  contrast     estimate    SE  df t.ratio p.value
##  Front - Back   nonEst    NA  NA     NA      NA 
##  Front - Both   -264.2  78.0 187 -3.388  0.0025 
##  Back - Both    nonEst    NA  NA     NA      NA 
## 
## Sever = S4:
##  contrast     estimate    SE  df t.ratio p.value
##  Front - Back    467.3 184.9 189  2.528  0.0328 
##  Front - Both    -71.7  74.3 192 -0.965  0.5996 
##  Back - Both    -539.0 187.0 187 -2.883  0.0122 
## 
## Degrees-of-freedom method: satterthwaite 
## P value adjustment: tukey method for comparing a family of 3 estimates

9.7.4 1992 leaf area analysis per system

## Type III Analysis of Variance Table with Satterthwaite's method
##               Sum Sq Mean Sq NumDF  DenDF F value    Pr(>F)    
## Status        413983  206992     2 189.87  4.9708  0.007867 ** 
## Sever        1149965  383322     3 188.12  9.2054 1.032e-05 ***
## Status:Sever  474768  158256     3 190.80  3.8005  0.011184 *  
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## $emmeans
##  Status emmean   SE   df lower.CL upper.CL
##  Front     521 29.3 35.4      462      580
##  Back   nonEst   NA   NA       NA       NA
##  Both   nonEst   NA   NA       NA       NA
## 
## Results are averaged over the levels of: Sever 
## Degrees-of-freedom method: satterthwaite 
## Confidence level used: 0.95 
## 
## $contrasts
##  contrast     estimate SE df z.ratio p.value
##  Front - Back   nonEst NA NA NA      NA     
##  Front - Both   nonEst NA NA NA      NA     
##  Back - Both    nonEst NA NA NA      NA     
## 
## Results are averaged over the levels of: Sever 
## Degrees-of-freedom method: satterthwaite 
## P value adjustment: tukey method for comparing a family of 3 estimates
## $emmeans
## Status = Front:
##  Sever emmean    SE    df lower.CL upper.CL
##  C        666  31.2  46.7    603.2      729
##  S1       297  66.8 158.9    164.7      429
##  S2       540  56.1 163.7    429.3      651
##  S4       582  42.0 106.7    498.7      665
## 
## Status = Back:
##  Sever emmean    SE    df lower.CL upper.CL
##  C     nonEst    NA    NA       NA       NA
##  S1       328 208.1 189.7    -82.4      738
##  S2    nonEst    NA    NA       NA       NA
##  S4       106 147.7 192.3   -185.2      398
## 
## Status = Both:
##  Sever emmean    SE    df lower.CL upper.CL
##  C     nonEst    NA    NA       NA       NA
##  S1       347  42.7  99.0    262.7      432
##  S2       402  39.4  89.1    324.1      481
##  S4       327  49.8 135.6    229.0      426
## 
## Degrees-of-freedom method: satterthwaite 
## Confidence level used: 0.95 
## 
## $contrasts
## Status = Front:
##  contrast estimate    SE  df t.ratio p.value
##  C - S1      369.2  69.7 194  5.296  <.0001 
##  C - S2      125.9  59.6 188  2.113  0.1528 
##  C - S4       84.0  46.3 185  1.814  0.2701 
##  S1 - S2    -243.3  83.9 194 -2.898  0.0216 
##  S1 - S4    -285.2  75.7 194 -3.768  0.0012 
##  S2 - S4     -41.9  65.9 188 -0.636  0.9204 
## 
## Status = Back:
##  contrast estimate    SE  df t.ratio p.value
##  C - S1     nonEst    NA  NA     NA      NA 
##  C - S2     nonEst    NA  NA     NA      NA 
##  C - S4     nonEst    NA  NA     NA      NA 
##  S1 - S2    nonEst    NA  NA     NA      NA 
##  S1 - S4     221.9 254.3 187  0.872  0.8191 
##  S2 - S4    nonEst    NA  NA     NA      NA 
## 
## Status = Both:
##  contrast estimate    SE  df t.ratio p.value
##  C - S1     nonEst    NA  NA     NA      NA 
##  C - S2     nonEst    NA  NA     NA      NA 
##  C - S4     nonEst    NA  NA     NA      NA 
##  S1 - S2     -55.0  52.1 186 -1.055  0.7173 
##  S1 - S4      20.0  59.8 184  0.334  0.9871 
##  S2 - S4      74.9  58.1 185  1.291  0.5700 
## 
## Degrees-of-freedom method: satterthwaite 
## P value adjustment: tukey method for comparing a family of 4 estimates
## $emmeans
## Sever = C:
##  Status emmean    SE    df lower.CL upper.CL
##  Front     666  31.2  46.7    603.2      729
##  Back   nonEst    NA    NA       NA       NA
##  Both   nonEst    NA    NA       NA       NA
## 
## Sever = S1:
##  Status emmean    SE    df lower.CL upper.CL
##  Front     297  66.8 158.9    164.7      429
##  Back      328 208.1 189.7    -82.4      738
##  Both      347  42.7  99.0    262.7      432
## 
## Sever = S2:
##  Status emmean    SE    df lower.CL upper.CL
##  Front     540  56.1 163.7    429.3      651
##  Back   nonEst    NA    NA       NA       NA
##  Both      402  39.4  89.1    324.1      481
## 
## Sever = S4:
##  Status emmean    SE    df lower.CL upper.CL
##  Front     582  42.0 106.7    498.7      665
##  Back      106 147.7 192.3   -185.2      398
##  Both      327  49.8 135.6    229.0      426
## 
## Degrees-of-freedom method: satterthwaite 
## Confidence level used: 0.95 
## 
## $contrasts
## Sever = C:
##  contrast     estimate    SE  df t.ratio p.value
##  Front - Back   nonEst    NA  NA     NA      NA 
##  Front - Both   nonEst    NA  NA     NA      NA 
##  Back - Both    nonEst    NA  NA     NA      NA 
## 
## Sever = S1:
##  contrast     estimate    SE  df t.ratio p.value
##  Front - Back    -31.3 217.1 188 -0.144  0.9886 
##  Front - Both    -50.7  76.0 193 -0.667  0.7826 
##  Back - Both     -19.4 210.7 186 -0.092  0.9954 
## 
## Sever = S2:
##  contrast     estimate    SE  df t.ratio p.value
##  Front - Back   nonEst    NA  NA     NA      NA 
##  Front - Both    137.6  64.1 187  2.148  0.0831 
##  Back - Both    nonEst    NA  NA     NA      NA 
## 
## Sever = S4:
##  contrast     estimate    SE  df t.ratio p.value
##  Front - Back    475.7 151.9 188  3.132  0.0057 
##  Front - Both    254.4  61.1 192  4.167  0.0001 
##  Back - Both    -221.3 153.6 187 -1.440  0.3224 
## 
## Degrees-of-freedom method: satterthwaite 
## P value adjustment: tukey method for comparing a family of 3 estimates

9.7.5 Potential plots for manuscript

Four panel, total and average leaf area in both years:

(This can be further cleaned up to only have one legend, etc.)

For 1991, the leaf area in each year, with the total leaf area as an inset:

This isn’t perfect, but if we like this idea, I can clean up the plot further (e.g. make the inset plot fit perfectly within the box bounding the larger plot).

For 1991, tri-panel figure with average leaf area, total leaf area, and bar plots.

## fixed-effect model matrix is rank deficient so dropping 1 column / coefficient
## Cannot use mode = "kenward-roger" because *pbkrtest* package is not installed
## fixed-effect model matrix is rank deficient so dropping 1 column / coefficient
## Cannot use mode = "kenward-roger" because *pbkrtest* package is not installed
## 
## Attaching package: 'lemon'
## The following object is masked from 'package:purrr':
## 
##     %||%
## The following objects are masked from 'package:ggplot2':
## 
##     CoordCartesian, element_render
## Warning: Removed 1 rows containing missing values (geom_point).
## Warning: Removed 1 rows containing missing values (geom_segment).
## Warning: Removed 1 rows containing missing values (geom_point).
## Warning: Removed 1 rows containing missing values (geom_segment).
## Warning: Removed 1 rows containing missing values (geom_point).
## Warning: Removed 1 rows containing missing values (geom_segment).

The same thing for 1992: