Hydro-climatic variability and perturbations in Mexico's north-western temperate forests

Climate variability and/or change control/s the local hydrologic cycle and consequently forest perturbations such as wildfires and bark beetle outbreaks. This case study addresses the following concerns: (a) the long-term trends in precipitation, potential and actual evapotranspiration, run-off, soil moisture content, number of wildfires, burned area, and bark beetle outbreaks and (b) the manner in which the fire occurrence, fire size, and beetle outbreaks are related to these hydrologic variables and multi-decadal climate indices in Mexico's north-western temperate forests. Using the daily measurements of precipitation and evaporation as well as the modelled interception loss and evapotranspiration, run-off and soil moisture content were computed using a mass balance budget model. Mann-Kendall, linear regression, and autoregressive integrated moving averaging techniques were used to evaluate the statistical significance of monotonic trends on the first momentum for the monthly and annual time series of hydro-climate (1945-2007), forest wildfire (1970-2012), and bark beetle infestation (1999-2012) data. The statistical analysis showed time series to be stationary in the first momentum. Recent wildfires and bark beetle population eruptions are associated with low modelled dry season soil moisture over several years. Drought spells, frosts, and pulses of high area burned, and high number of wildfires preceded acute discrete bark beetle population eruptions. Copyright (C) 2014 John Wiley & Sons, Ltd.