## Warning: package 'zoo' was built under R version 4.0.5
## Warning: package 'multcomp' was built under R version 4.0.5
## Warning: package 'emmeans' was built under R version 4.0.5

1 Focal mesquite status

There were no significant interactions in models assessing the status of the focal mesquite tree (having no live resprouts or having at least 1 live resprout) in 2019 or 2020 so they were removed from the model and odds ratios determined for main effects. Fire energy was the only significant predictor in both years. Holding all other variables constant, being in a low fire energy plot increased the odds of a focal mesquite having at least 1 live resprout by a factor of 7-1085 and 1.4-1747 in 2019 and 2020 respectively (Table 1.1).

Table 1.1: Results of logistic regression for focal mesquite status
  Focal Mesquite Status 2019 Focal Mesquite Status 2020
Predictors Odds Ratios Conf. Int (95%) p-Value Odds Ratios Conf. Int (95%) p-Value
(Intercept) 244.83 0.01 – 82600234.73 0.310 5644.63 0.05 – 11339980762.39 0.145
Fire Energy (Low) 48.98 7.13 – 1084.58 <0.001 13.03 1.40 – 1747.46 0.020
Base Exposure (Yes) 0.38 0.05 – 2.07 0.270 0.61 0.09 – 3.45 0.578
Soil Moisture 1.10 0.84 – 1.52 0.505 0.95 0.72 – 1.20 0.657
Relative Humidity 0.76 0.50 – 1.05 0.093 0.82 0.51 – 1.17 0.279
Wind Speed 1.05 0.74 – 1.51 0.765 0.85 0.60 – 1.18 0.328
Observations 48 48

2 Number of total resprouts

In 2019, there was a significant interaction between fire energy and basal exposure in the model for total resprouts (Table 1.2). High energy plots had fewer resprouts than low energy plots regardless of base exposure; however, low fire energy plots with bases exposed had fewer resprouts than low fire energy plots with intact bases while high fire energy plots had similar numbers of resprouts in plots with bases exposed and those with bases intact (Figure 2.1). In 2020, the interaction between fire energy and basal exposure was no longer significant, so it was removed from the model; however, a significant interaction manifested between fire energy and wind speed, which was not evident in 2019 (Table 1.1). High fire energy plots had fewer resprouts than low fire energy plots at lower windspeeds, but that difference did not hold under higher wind speeds as the number of resprouts in low energy plots decreased with increasing windspeed (Figure 2.1). Basal exposure was no longer a significant predictor of total resprouts in 2020 (Table 1.2, Figure2.1).

(Table 1.2) Results of negative binomial regression for number of total resprouts
  Total Resprouts 2019 Total Resprouts 2020
Predictors Incidence Rate Ratios Conf. Int (95%) p-Value Incidence Rate Ratios Conf. Int (95%) p-Value
(Intercept) 2.81 0.29 – 27.07 0.371 0.55 0.08 – 4.00 0.556
Fire Energy (Low) 2.70 1.13 – 6.48 0.026 47.41 11.75 – 191.24 <0.001
Base Exposure (Yes) 0.14 0.04 – 0.54 0.004 1.06 0.68 – 1.66 0.787
Soil Moisture 1.04 0.97 – 1.12 0.288 1.04 0.99 – 1.09 0.147
Relative Humidity 1.09 1.03 – 1.16 0.004 1.07 1.00 – 1.15 0.039
Wind Speed 0.83 0.70 – 0.97 0.023 1.01 0.95 – 1.08 0.670
Fire Energy (Low)*Base
Exposure (Yes) 		8.39 1.89 – 37.25 0.005
Fire Energy (Low)*Wind
Speed 		0.74 0.63 – 0.88 0.001
Observations 29 41
R2 Nagelkerke 0.919 0.939




Total number of resprouts in 2019 (top) broken down by fire energy and basal exposure and in 2020 (bottom) shown seperately for base exposure (left), and predicted values for number of total resprouts by wind speed (right). SIgnificant differences are denoted with different letters. There was a significant interaction between fire energy and basal exposure in 2019, but not in 2020; in 2020 there was a significant fire energy by wind speed interaction.

Figure 2.1: Total number of resprouts in 2019 (top) broken down by fire energy and basal exposure and in 2020 (bottom) shown seperately for base exposure (left), and predicted values for number of total resprouts by wind speed (right). SIgnificant differences are denoted with different letters. There was a significant interaction between fire energy and basal exposure in 2019, but not in 2020; in 2020 there was a significant fire energy by wind speed interaction.

3 Epicormic resprouting status

There were no significant interactions in models assessing the status of epicormic resprouting (having no live epicormic resprouts or having at least 1 liveepicormic resprout) in 2019 or 2020 so they were removed from the model and odds ratios determined for main effects. Fire energy was a significant predictor in both years. Holding all other variables constant, being in a low fire energy plot increased the odds of a focal mesquite having at least one live epicormic resprout by a factor of ~8-760 and 7-767 in 2019 and 2020 respectively (Table 2.1). Wind speed was also a significant predictor of whether a focal mesquite had an epicormic resprout, with a one kph increase in wind speed reducing the odds of a focal mesquite having at least one live epicormic resprout by a factor of 0.03-0.66 in 2019 and 0.15-0.73 in 2020 (Table 2.1).

Table 2.1: Results of logistic regression for epicormic resprouting status
  Epicormic Resprouting Status 2019 Epicormic Resprouting Status 2020
Predictors Odds Ratios Conf. Int (95%) p-Value Odds Ratios Conf. Int (95%) p-Value
(Intercept) 8.40 0.00 – 1297269.43 0.701 9.53 0.00 – 1131294.36 0.675
Fire Energy (Low) 47.24 7.90 – 760.24 <0.001 45.07 7.08 – 766.62 <0.001
Base Exposure (Yes) 0.81 0.12 – 4.66 0.808 1.12 0.17 – 6.91 0.896
Soil Moisture 0.93 0.70 – 1.20 0.576 0.96 0.74 – 1.25 0.771
Relative Humidity 1.01 0.78 – 1.34 0.962 1.02 0.79 – 1.35 0.870
Wind Speed 0.61 0.33 – 0.97 0.036 0.52 0.27 – 0.85 0.006
Observations 48 48

4 Number of epicormic resprouts

There were no significant interaction in models assessing the number of epicormic resprouts in 2019 or 2020 so they were removed from the model and incident rate ratios determined for main effects. Since there was only one high energy focal mesquite that resprouted epicormically, we did not include fire treatment in this assessment. Basal exposure was not a significant predictor of epicormic resprouts in 2019 or 2020 (Table 2.2, Figure 4.1). Wind speed were significant predictors of mean number of epicormic resprouts in both years. For each kph increase in wind speed, the mean number of epicormic resprouts decreased by 3-50% in 2019 and 6-65% in 2020 (Table 2.2).

Table 2.2: Results of negative binomial regression for number of epicormic resprouts
  Epicormic Resprouts 2019 Epicormic Resprouts 2020
Predictors Incidence Rate Ratios Conf. Int (95%) p-Value Incidence Rate Ratios Conf. Int (95%) p-Value
(Intercept) 21.13 0.01 – 44982.62 0.435 48.70 0.02 – 125028.80 0.332
Number of Basal Resprouts 0.93 0.83 – 1.04 0.195 0.90 0.79 – 1.02 0.090
Base Exposure (Yes) 0.92 0.19 – 4.33 0.913 0.80 0.16 – 4.03 0.788
Soil Moisture 1.05 0.87 – 1.26 0.609 1.04 0.86 – 1.27 0.661
Relative Humidity 1.11 0.98 – 1.25 0.087 1.12 0.97 – 1.28 0.120
Wind Speed 0.70 0.50 – 0.97 0.033 0.63 0.42 – 0.94 0.023
Observations 20 19
R2 Nagelkerke 0.661 0.707




Number of epicormic resprouts in 2019 (top) and in 2020 (bottom) by fire energy (left) and basal exposure (right). Fire energy and basal exposure are displayed seperately since there was not a significant interaction between them in either year. Significant differences are denoted with different letters within a panel.

Figure 4.1: Number of epicormic resprouts in 2019 (top) and in 2020 (bottom) by fire energy (left) and basal exposure (right). Fire energy and basal exposure are displayed seperately since there was not a significant interaction between them in either year. Significant differences are denoted with different letters within a panel.

Scatter plot of number of epicormic resprouts by the number of basal resprouts for high-energy plots (left) and low-energy plots (right).

Figure 4.2: Scatter plot of number of epicormic resprouts by the number of basal resprouts for high-energy plots (left) and low-energy plots (right).

5 Basal resprouting status

There were no significant interactions in models assessing the status of basal resprouting (having no live basal resprouts or having at least one live basal resprout) in 2019 or 2020 so they were removed from the model and odds ratios determined for main effects. Fire energy was a significant predictor of basal resprouting in 2019 but not 2020. Holding all other variables constant, being in a low fire energy plot increased the odds of a focal mesquite having at least one live basal resprout by a factor of 2-31 in 2019 but did not change the odds of having at least one live basal resprout in 2020 (Table 3.1).

Table 2.1: Results of logistic regression for basal resprouting status
  Basal Resprouting Status 2019 Basal Resprouting Status 2020
Predictors Odds Ratios Conf. Int (95%) p-Value Odds Ratios Conf. Int (95%) p-Value
(Intercept) 2.69 0.00 – 5272.09 0.791 53.07 0.03 – 146393.21 0.297
Fire Energy (Low) 6.65 1.77 – 30.97 0.004 1.13 0.30 – 4.35 0.851
Base Exposure (Yes) 0.30 0.07 – 1.07 0.065 0.41 0.11 – 1.42 0.163
Soil Moisture 0.96 0.80 – 1.15 0.684 0.90 0.74 – 1.07 0.232
Relative Humidity 0.94 0.77 – 1.13 0.491 0.96 0.80 – 1.16 0.674
Wind Speed 1.10 0.84 – 1.45 0.493 0.97 0.73 – 1.29 0.814
Observations 48 48

6 Number of basal resprouts

There were no significant interactions in models assessing the number of basal resprouts in 2019 or 2020 so they were removed from the model and incident rate ratios determined for main effects. In 2019, high energy plots had fewer resprouts than low energy plots, but by 2020 high and low energy plots had similar numbers of basal resprouts (Table 3.1, Figure 6.1). Basal exposure was also a significant predictor of basal resprouts in 2019, but was not in 2020. Plots with bases exposed had 1-83% fewer basal resprouts than intact plots regardless of fire treatment in 2019, but by 2020, exposed and intact plots had similar numbers of basal resprouts (Table 3.1, Figure 6.1). In addition, relative humidity was a significant predictor of mean basal resprouts in 2019, but not 2020. For each percent increase in relative humidity, the mean number of basal resprouts increased by 2-18% in 2019 (Table 3.1).

Table 2.1: Results of negative binomial regression for basal resprouts
  Basal Resprouts 2019 Basal Resprouts 2020
Predictors Incidence Rate Ratios Conf. Int (95%) p-Value Incidence Rate Ratios Conf. Int (95%) p-Value
(Intercept) 168.40 13.58 – 2088.10 <0.001 68.64 4.20 – 1120.55 0.003
Fire Energy (Low) 1.97 1.07 – 3.64 0.029 1.31 0.86 – 2.00 0.211
Base Exposure (Yes) 0.41 0.17 – 0.99 0.047 0.69 0.43 – 1.10 0.114
Soil Moisture 1.00 0.90 – 1.12 0.952 0.99 0.94 – 1.05 0.726
Relative Humidity 0.90 0.82 – 0.98 0.021 0.94 0.86 – 1.02 0.135
Wind Speed 0.96 0.84 – 1.09 0.490 0.98 0.89 – 1.08 0.652
Observations 22 34
R2 Nagelkerke 0.664 0.367




Number of basal resprouts in 2019 (top) and in 2020 (bottom) by fire energy (left) and basal exposure (right). Fire energy and basal exposure are displayed seperately since there was not a significant interaction between them in either year. Significant differences are denoted with different letters within a panel.

Figure 6.1: Number of basal resprouts in 2019 (top) and in 2020 (bottom) by fire energy (left) and basal exposure (right). Fire energy and basal exposure are displayed seperately since there was not a significant interaction between them in either year. Significant differences are denoted with different letters within a panel.