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To understand the impacts of changing climate and wildfire activity on conifer forests, we studied how wildfire and post-fire seasonal climate conditions influence western larch (Larix occidentalis) regeneration across its range in the northwestern US. We destructively sampled 1651 seedlings from 57 sites across 32 fires that burned at moderate or high severity between 2000 and 2015; sites were within 100 m of reproductively mature western larch. Using dendrochronological methods, we estimated germination years of seedlings to calculate annual recruitment rates. We used boosted regression trees to model the annual probability of recruitment as a function of (i) ‘wildfire-related factors’ including distance to seed...
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Abstract (from http://journals.ametsoc.org/doi/abs/10.1175/JHM-D-13-0167.1): Drought indices are often used for monitoring interannual variability in macroscale hydrology. However, the diversity of drought indices raises several issues: 1) which indices perform best and where; 2) does the incorporation of potential evapotranspiration (PET) in indices strengthen relationships, and how sensitive is the choice of PET methods to such results; 3) what additional value is added by using higher-spatial-resolution gridded climate layers; and 4) how have observed relationships changed through time. Standardized precipitation index, standardized precipitation evapotranspiration index (SPEI), Palmer drought severity index,...
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Abstract (from http://journals.ametsoc.org/doi/abs/10.1175/JAMC-D-15-0276.1): Remotely sensed land skin temperature (LST) is increasingly being used to improve gridded interpolations of near-surface air temperature. The appeal of LST as a spatial predictor of air temperature rests in the fact that it is an observation available at spatial resolutions fine enough to capture topoclimatic and biophysical variations. However, it remains unclear if LST improves air temperature interpolations over what can already be obtained with simpler terrain-based predictor variables. Here, the relationship between LST and air temperature is evaluated across the conterminous United States (CONUS). It is found that there are significant...
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Abstract (from CSIRO Publishing): Soil moisture conditions are represented in fire danger rating systems mainly through simple drought indices based on meteorological variables, even though better sources of soil moisture information are increasingly available. This review summarises a growing body of evidence indicating that greater use of in situ, remotely sensed, and modelled soil moisture information in fire danger rating systems could lead to better estimates of dynamic live and dead herbaceous fuel loads, more accurate live and dead fuel moisture predictions, earlier warning of wildfire danger, and better forecasts of wildfire occurrence and size. Potential uses of soil moisture information in existing wildfire...
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