Table 1

Table 1. Plant flammability traits
Classes for component traits for estimating plant flammability. Flammability itself is calculated as the average class value (rounded to one decimal) over all component traits. Flammability increases from 1 to 5. For this calculation, twig drying time (which is probably closely negatively linked with twig dry-matter content, TDMC; see Section 4.2) is optional

Component trait
Flammability class
1 2 3 4 5
Twig dry-matter content (mg g–1) <200 200–400 400–600 600–800 >800
Twig drying time (day) ≥5 4 3 2 ≤1
Leaf dry-matter content (mg g–1) <150mg 150–300 300–500 500–700 >700
Degree of ramification (branching)
(number of ramification orders)
No branches Only 1st-order
2 orders of
3 orders of
≥4 orders of
Leaf size (lamina area) (mm2) >25 000 2500–25 000 250–2500 25–250 <25
Standing fine litter in driest season None as one litter unit Some Substantial
(with dead leaves or
twigs or flaking bark)
More dead than
live fine mass
above ground
Shoot dies back
entirely, standing as
one litter unit
Volatile oils, waxes and/or resins None Some Substantial Abundant Very abundant