Characterizing persistent unburned islands within the Inland Northwest USA

Fire Ecology

Table 4 Two-sample Kolmogorov-Smirnov D statistic and P-values to test significance of difference between the distributions of topographic metrics among unburned islands within fires in the Inland Pacific Northwest from 1984 to 2014 based on their degree of persistence and fire regime group (FRG). The topographic metrics used for analysis were Topographical Position Index (TPI; Weiss 2001), Topographic Wetness Index (TWI; Beven and Kirkby 1979), Terrain Ruggedness Index (TRI; Riley et al. 1999), slope, the cosine of the aspect (CosAsp), and the transformed aspect (TRASP; Roberts and Cooper 1989)

FRG	TPI		TWI		TRI		Slope		CosAsp		TRASP		Number of observations
FRG	D	P	D	P	D	P	D	P	D	P	D	P	Number of observations
All	0.0425	<0.0001	0.0689	<0.0001	0.1108	<0.0001	0.1030	<0.0001	0.0483	<0.0001	0.0492	<0.0001	n₁ = 30 000 n₂ = 30 000
I	0.1077	<0.0001	0.1352	<0.0001	0.1847	<0.0001	0.1747	<0.0001	0.0544	<0.0001	0.0508	<0.0001	n₁ = 4 006 n₂ = 4 667
II	0.1421	<0.0001	0.0736	0.1234^*	0.2696	<0.0001	0.2719	<0.0001	0.0992	0.0126^**	0.0562	0.3906^*	n₁ = 939 n₂ = 354
III	0.048	<0.0001	0.0751	<0.0001	0.1253	<0.0001	0.1164	<0.0001	0.0748	<0.0001	0.0799	<0.0001	n₁ = 8 978 n₂ = 10 097
IV	0.0412	<0.0001	0.0726	<0.0001	0.1118	<0.0001	0.1016	<0.0001	0.0475	<0.0001	0.0305	<0.0001	n₁ = 15 136 n₂ = 13 854
V	0.0804	0.0035	0.0748	0.0082	0.058	0.0736^*	0.0625	0.0429^**	0.1256	<0.0001	0.1215	<0.0001	n₁ = 941 n₂ = 1 028