Short- and Long-Term Effects on Fuels, Forest Structure, and Wildfire Potential from Prescribed Fire and Resource Benefit Fire in Southwestern Forests, USA

Hunter, Molly E.; Iniguez, Jose M.; Lentile, Leigh B.

doi:10.4996/fireecology.0703108

Fire Ecology

Table 2 Average and standard error (in parentheses) of measured variables in ponderosa pine forests in the Gila National Forest, New Mexico, USA. Unburned areas are unburned for the last century. Numbers next to fire management strategy categories represents number of plots in each category. Different letters represent significant differences between fire management strategy categories for each measured variable. See Table 1 for description of fire management strategy categories.

From: Short- and Long-Term Effects on Fuels, Forest Structure, and Wildfire Potential from Prescribed Fire and Resource Benefit Fire in Southwestern Forests, USA

variable	Unburned (21)	PF (24)	RBF-L (31)	RBF-M (16)	Two RBF (20)	Three RBF (10)
CBI^A	—	0.54 (0.09)^a	0.87 (0.09)^b	2.03 (0.11)^c	—	—
10 hr fuel load (Mg ha⁻¹)	1.69 (0.21)^b	1.41 (0.19)*	0.86 (0.17)^a	1.75 (0.24)*	1.25 (0.21)^ab	1.06 (0.30)*
100 hr fuel load (Mg ha⁻¹)	2.79 (0.51)^ab	2.63 (0.48)^b	0.90 (0.42)^a	2.72 (0.59)*	1.79 (0.52)^ab	0.96 (0.74)^ab
Litter depth (cm)	1.86 (0.14)^b	1.45 (0.14)^b	1.13 (0.12)^ab	0.83 (0.17)^a	1.00 (0.15)^ab	1.10 (0.21)*
Duff depth (cm)	0.62 (0.10)^b	0.57 (0.10)^b	0.30 (0.09)^ab	0.07 (0.12)^a	0.13 (0.11)^a	0.13 (0.15)^a
Forb cover (%)	4.19 (0.94)^ab	5.24 (0.88)^b	4.22 (0.77)^b	9.96 (1.07)^b	5.53 (0.96)^b	1.72 (1.36)^a
Grass cover (%)	10.80 (1.87)*	7.80 (1.75)^a	10.68 (1.54)^ab	7.17 (2.14)^a	13.49 (1.91)^b	26.04 (2.70)^ab
Soil exposure (%)	3.97 (1.46)^ab	3.30 (1.37)^a	5.51 (1.20)^ab	10.26 (1.67)^b	7.49 (1.50)^ab	6.28 (2.12)^b
BA (m² ha⁻¹)	27.91 (2.48)^bc	30.53 (2.32)^c	21.40 (2.04)^b	5.70 (2.84)^a	29.08 (2.54)^bc	25.40 (3.60)^bc
Trees ha⁻¹	933.33 (65.71)^e	552.08 (61.47)^de	380.65 (54.09)^cd	84.38 (75.29)^a	337.50 (67.34)^cd	310.00 (95.23)^bc
Tree seedling ha⁻¹	602.38 (65.03)^b	131.25 (60.83)^ab	45.16 (53.52)^a	15.63 (74.50)^a	72.50 (66.63)^a	30.00 (94.23)^a
CBD-stand (kg m⁻³)^B	0.28 (0.02)^d	0.21 (0.02)^cd	0.15 (0.01)^b	0.03 (0.02)^a	0.15 (0.02)^bc	0.14 (0.03)^bc
CBD-allometric (kg m⁻ ³)^C	0.15 (0.02)^b	0.12 (0.01)^b	0.10 (0.01)^b	0.04 (0.02)^a	0.11 (0.02)^b	0.15 (0.02)^b
CBH-20 (m)^D	1.16 (0.49)^a	3.66 (0.46)^b	3.32 (0.40)^b	4.36 (0.56)^b	2.70 (0.50)^ab	4.91 (0.71)^b
Fire type-stand^E	Active	Active	Passive	Surface	Passive	Surface
Fire type-allometric	Passive	Passive	Passive	Surface	Passive	Surface

^A Only in this case, n = 20 for RBF-L. CBI ranges from 0 to 3; 0 = no effect; 0.5 to 1 = low severity; 1.5 to 2 = moderate severity; 2.5 to 3 = high severity.
^B Canopy bulk density calculated using a stand-level regression equation.
^C Canopy bulk density calculated using allometric equations.
^D Twentieth percentile canopy base height.
^E Predicted fire behavior in Nexus using ninetieth percentile weather conditions. Active represents active crown fire, passive represents passive crown fire, and surface represents surface fire.

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