Effect Of Aspect And Slope On Forest-floor Fuel Moisture And Correction In FWI System

In order to know the impact of different slope and aspect to the moisture of forest-floor fuel, and then explore the major meteorological and terrain factors on the moisture of forest-floor fuel, experiments were carried out in this paper to measure the sample moisture of original broad-leaved Korean Pine mixed forest, and then contract the meteorological data and standard stations’meteorological data in the FWI system, to achieve the purpose correcting the FWI index, which provides data support for the research of the fuel moisture variation and impact factors.The results show that the forest-floor dead fuel moisture content of diurnal variation was evident. The forest-floor dead fuel moisture content in lower slope was higher than that in high slope, fuel moisture content in shady aspect was higher than that in sunny aspect, the size of the surface fuel moisture content were lower slope in shady aspect>high slope in shady aspect> valley> lower slope in sunny aspect>high slope in sunny aspect.The forest-floor dead fuel moisture of different slope and aspect was significantly correlated with the air temperature, relative humidity and precipitation (P<0.05), among which was negatively correlated with the air temperature and relative humidity and positively correlated with precipitation. The degrees of impact on fuel moisture in turn are precipitation, air temperature and relative humidity. The fuel moisture content changing with the wind speed was not significantly correlated. The slope impact on precipitation directly, resulting in the fuel moisture in shady slope related to precipitation most significantly.FFMC value in high slope in sunny aspect was higher than that in lower slope in sunny aspect. DMC, DC and BUI value in high slope was higher than that lower slope. The trend of FWI value was reduced. FWI standard deviation calculating from field-measured meteorological data was less than that from standard meteorological data, and correlation at the P<0.05differences were significant. FWI value in sunny slope was most significantly related to the standard FWI value. FWI error value between valley and standard was the most smallest. The results suggest that FWI value in different aspect and slope which was derived from measured meteorological data was better than that from standard meteorological data.