Ecological Archives E096-166-A3

Sharon Hood, Anna Sala, Emily K. Heyerdahl, and Marion Boutin. 2015. Low-severity fire increases tree defense against bark beetle attacks. Ecology 96:15561565. http://dx.doi.org/10.1890/14-0487.1

Appendix C. Model statistics comparing total duct area before and after one fire, before and after frequent fire, and with climate.

Table C1. Model results comparing total duct area (mm2 year-1) before and after one fire, before and after frequent fire, and with climate. One fire: Montana and Utah sites, where fire = burned and unburned; time = before fire and after fire; ring area = ring width*increment core diameter. Frequent fire: Idaho and Oregon sites, where fire = fires excluded, fires not excluded; period = before and after fire exclusion; ring area = ring width * increment core diameter. PPT_depart = departure from 30-year normal July precipitation. Tmax_depart = departure from 30-yearnormal July maximum temperature. 30-year normal = 1981–2010.

Effect

df

F value

P value

Duct Response to One Fire

Montana

Time

25

0

0.9594

Fire

25

33.04

<.0001

Fire * Time

25

7.45

0.0115

Ring area

25

17.56

0.0003

Utah

Time

12

10.49

0.0822

Fire

12

3.60

0.0071

Fire * Time

12

3.04

0.1065

Ring area

12

6.03

0.0303

Duct Response to Frequent, Low-severity Fire

Idaho

Fire

14

10.30

0.0063

Period

14

10.60

0.0057

Fire * Period

14

8.76

0.0104

Ring area

4795

1177.47

<0.0001

Oregon

Period

4

10.07

0.0338

Ring area

871

68.79

<0.0001

Duct Response to Climate

PPT_depart

65

15.68

0.0002

Tmax_depart

65

12.79

0.0007

PPT_depar*Tmax_depar

65

1.24

0.2692


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