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Titolo:
WILDLAND FIRE PATCH DYNAMICS IN THE CHAPARRAL OF SOUTHERN CALIFORNIA AND NORTHERN BAJA-CALIFORNIA
Autore:
MINNICH RA; CHOU YH;
Indirizzi:
UNIV CALIF RIVERSIDE,DEPT EARTH SCI RIVERSIDE CA 92521
Titolo Testata:
International journal of wildland fire
fascicolo: 3, volume: 7, anno: 1997,
pagine: 221 - 248
SICI:
1049-8001(1997)7:3<221:WFPDIT>2.0.ZU;2-H
Fonte:
ISI
Lingua:
ENG
Soggetto:
MIXED-CONIFER FOREST; SUB-ALPINE FORESTS; MANAGEMENT POLICIES; LANDSCAPE DIVERSITY; PLANT-COMMUNITIES; CLIMATE-CHANGE; SOIL-MOISTURE; SIMULATION; SUCCESSION; PATTERNS;
Keywords:
TIME-DEPENDENT FIRE REGIMES; PATCH DYNAMICS; CHAPARRAL; FIRE WEATHER; CALIFORNIA; BAJA CALIFORNIA; LIGHTNING; FIRE WEATHER; FIRE SUPPRESSION;
Tipo documento:
Review
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
117
Recensione:
Indirizzi per estratti:
Citazione:
R.A. Minnich e Y.H. Chou, "WILDLAND FIRE PATCH DYNAMICS IN THE CHAPARRAL OF SOUTHERN CALIFORNIA AND NORTHERN BAJA-CALIFORNIA", International journal of wildland fire, 7(3), 1997, pp. 221-248

Abstract

In ecosystems where fire occurrence has significant time-dependence, fire sequences should exhibit system-regulation that is distinguished by nonrandom (nonstationary), self-organizing patch dynamics related to spatially constrained fire probabilities. Exogenous factors such as fire weather, precipitation variability, and terrain alter the flammability of vegetation and encourage randomness in fire occurrence withinpre-existing patch structure. In Californian chaparral, the roles of succession/fuel build-up and exogenous factors is examined by taking advantage of a 100 yr ''natural experiment'' in southern California (SCA) and northern Baja California, Mexico (BCA), where factors influencing fire occurrence have been systematically altered by divergent management systems. In SCA, suppression has been practiced since 1900. In BCA, fire control was not official policy until the 1960s and has not been effectively practiced. Fire perimeter histories for 1920-1971 in SCA and BCA, reconstructed from fire history records and repeat aerial photographs, are compared for fire frequency (events/area), size, rotation periods, stand age structure, ignition rates, weather, burning season, and drought. Landscape-scale fire rotation periods are long (approximate to 70 yr) regardless of management policies because fire occurrence is driven by the gradual development of fire hazard during succession, produced by small annual increments of growth and litterfall, as well as by high fuel moisture in evergreen shrubs. Without fire control frequent fires establish fine-grained mosaics. Fire control reduces fire frequencies, increases fire size, and encourages coarse-scale patch structure. Patch dynamics exhibit evidences of nonrandom turnover. Fire size distributions reflect the nearest-neighbor distances between patches below some age-dependent combustion threshold (CT) in the patch mosaic that resist the spread of fires in stands older than CT. Regional burn rates are poorly related to fire frequency, ignition rates, drought, and terrain. The small size of fires in BCA may be reinforced by interactions between fire and pre-existing, fine-grained patchstructure, and by random fire occurrence in the probability distributions of fire weather and climate. In SCA, fires are nonrandomly restricted by fire control to extreme weather.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 28/01/20 alle ore 15:07:49