Relative Contributions of Forest Vegetation, Land Cover, Topography and Climate in Explaining Fire Regime Patterns (1974–2005) in Peninsular Spain

Table 2

Explanatory variables, grouped in the four sets, code, units, description, and the number of times each one has been chosen in the RDA analyses performed for the 15 territories.

Environmental variables				Times selected
Set	Code	Units	Description	In first position	In the model
(1) Type of forest vegetation
IFN-2	Conif_#	%	Plots with conifers versus total number of plots	0	3
	Conif_BA	%	Basal area of conifers versus total basal area	0	0
	Scler_#	%	Plots with sclerophyll versus total number of plots	0	0
	Scler_BA	%	Basal area of sclerophyll versus total basal area	0	3
	Decid_#	%	Plots with deciduous versus total number of plots	0	1
	Decid_BA	%	Basal area of deciduous versus total basal area	0	0
(2) Type of land cover
CLC-1	For_area	%	Forest area versus total area	7	12
	Wd_For	%	Wooded forest versus forest area	1	6
	Nwd_For	%	Non wooded forest versus forest area	0	0
	Dec_Wd	%	Deciduous forest versus wooded forest area	0	3
	Con_Wd	%	Coniferous forest versus wooded forest area	0	4
	Mix_Wd	%	Mixed forest versus wooded forest area	0	0
	Agr_Nwd	%	Agroforest area versus non wooded forest area	0	1
	Shr_Nwd	%	Shrubland area versus non wooded forest area	1	1
(3) Topographic characterization
DTM	Elev_ran	m	Range of elevations	0	3
	Elev_avg	m	Average of elevations	3	10
	Elev_dev	m	Standard deviation of elevations	0	4
	Slo_ran	%	Range of slopes	0	2
	Slo_avg	%	Average of slopes	0	2
	Slo_dev	%	Standard deviation of slopes	0	1
(4) Climatic characterization
Aemet	Prec_avg	mm	Mean precipitation for 1961–1990	2	5
	Prec_var	mm	Variance for the yearly precipitation	1	4
	Temp_avg	°C	Mean temperature (at 2 meters)	0	3
	Temp_mx	°C	Mean of the yearly maximum temperatures	0	2
	Wind_avg	m/s	Mean wind speed (at 10 m)	0	5
	Wind_mx	m/s	Mean of maximum yearly wind speed	0	1