Abstract
It has been suggested that large, high-severity fires historically structured warm-dry mixed conifer forests in the American South-west. To test this, we reconstructed fire regime characteristics of an 1135-ha (11.3km2) mixed conifer landscape in northern Arizona using complementary approaches. We analysed composite fire intervals, point fire intervals, natural fire rotation, landscape characteristics and forest age structure. Composite analysis of cross-dated fire scars from 133 trees indicated a mean fire interval (MFI) of 2.0-8.5 years between 1670 and 1879. Frequent fires halted abruptly after 1879. Mean point fire interval (MPFI) was 11.8 years and ranged 2-61 years. Mean fire rotation was 14.4 years. Density of most occurring tree species increased dramatically after fire regime disruption, with south-western white pine (Pinus strobiformis) and white fir (Abies concolor) showing large numerical gains. Tree establishment patterns compared with widespread fire dates did not suggest historical high-severity fires at the site level. Although strong evidence of high-severity fire at finer scales was lacking, spatial locations of 'young' plots suggested the possibility of historical high-severity disturbances ≤25ha in size. The historical fire regime on this landscape was one of high-frequency, low-severity fires. Current conditions call for restoration of forest structure and function.
Original language | English (US) |
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Pages (from-to) | 680-689 |
Number of pages | 10 |
Journal | International Journal of Wildland Fire |
Volume | 24 |
Issue number | 5 |
DOIs | |
State | Published - 2015 |
Keywords
- forest restoration
- historical fire regime
- landscape change
- mean fire interval
- natural fire rotation
- point interval.
ASJC Scopus subject areas
- Forestry
- Ecology