Soil moisture in a southwestern mixed conifer forest

Increasing tree density in the Sacramento Mountains in southwestern New Mexico may be associated with reduced ground water recharge and lowered streamflow. This study was designed to analyze soil water content in the unsaturated zone to determine effects of tree density on soil moisture movement and ground water recharge. The study site is located in Cloudcroft, NM. Four paired plots were established to measure soil water content and soil temperature. Two paired plots were established in the ridge (2,601 m sea level) and two more in the valley (2,400 m sea level) on northern and southern aspects. Each paired plot was instrumented with a set of three soil moisture and temperature (ECH2O EC-TM) sensors under the tree canopy. At 20 cm depth, both ridge and valley soil volumetric water content (SVWC) was higher on northern aspect plots (27% ridge, 20 % valley) than on southern aspect plots (25% ridge, 9.5% valley). Similar differences were seen at 35 cm depth with higher SVWC on the northern aspect (25 % ridge, 24% valley) than on the southern aspect (19 % ridge, 10 % valley) It is likely that on unsaturated zone, aspect influences on SVWC for both places (ridge and valley) regardless of steepness (5-29 % ridge and 9-22 % valley) and tree density (300-500 tree ac-1 ridge and 500-700 tree ac-1 valley). These data, though still preliminary, will be used to estimate the water balance and ground water recharge in a mixed conifer forest.