Branching out: species-specific canopy architecture limits live crown fuel consumption in Intermountain West USA conifers

Fire Ecology

Table 2 Fuel characteristics and fuel class proportions for each species. \(\phi _{th}\) is the branchwood diameter below which fuel has a 50% likelihood of being consumed; \(SVR_{th}\) is the corresponding crown threshold surface area to volume ratio. Branchwood available as fuel (1 h avail) is shown as a proportion of total 1 h biomass. Biomass proportions within the 1 h fuel class are shown as well as foliage, 1 h, and 10 h fuel as a proportion of the average measured branch. Proportions are on a dry mass basis; 1 h skew is the skewness of the biomass distribution within the 1 h fuel class

1-h dist.	Species	Fuel characteristics			1-h branchwood			1-h skew	Total branch proportions
		\(\varvec{\phi }_{\varvec{th}}\)	\(\varvec{SV}\,\varvec{R}_{\varvec{th}}\)	1-h avail	0.1–2	2.1–4	4.1–6		Foliage	1-h	10-h
		mm	m-1	\(\hat{\varvec{p}}\)	\(\hat{\varvec{p}}\)				\(\hat{\varvec{p}}\)
Fine skew	ABGR	4.38	1560	0.80	0.42	0.34	0.24	0.87	0.45	0.17	0.38
	TSHE	5.89	1332	0.99	0.55	0.25	0.21	1.62	0.42	0.18	0.40
	THPL	4.38	1560	0.84	0.48	0.31	0.21	1.27	0.39	0.19	0.42
	PSME	3.44	1864	0.65	0.40	0.36	0.24	0.47	0.47	0.21	0.32
Normal	LAOC	1.98	2915	0.08	0.08	0.57	0.35	0	0.23	0.33	0.44
	ABLA	3.39	1906	0.64	0.35	0.41	0.23	0	0.47	0.17	0.35
	PIEN	3.33	1952	0.61	0.01	0.44	0.56	0	0.45	0.20	0.35
Coarse skew	PIAL	3.28	1906	0.15	0.32	0.44	0.24	− 1.37	0.45	0.19	0.36
	PICO	3.80	1696	0.41	0.00	0.23	0.77	− 0.40	0.39	0.20	0.41
	PIMO	4.79	1459	0.73	0.01	0.46	0.54	− 1.70	0.42	0.17	0.41
	PIPO	-	-	0.00	0.00	0.08	0.96	− 0.27	0.35	0.01	0.65