Stream temperature response to 50% strip-thinning in a temperate
forested headwater catchment
Abstract
We examined stream temperature response to 50% strip-thinning of a 20-
to 50-year-old Japanese cedar and cypress plantation in a 17-ha
headwater catchment. The thinning lines extended through the riparian
zone. Paired-catchment analysis was applied to estimate changes in daily
maximum, mean, and minimum stream temperatures for the first year
following treatment. Significant effects on daily maximum stream
temperature were found for April to August, ranging from 0.6 to 3.9 °C,
similar to the magnitude of effect found in previous studies involving
50% random thinning. Multiple regression analysis revealed that
treatment effects for maximum daily stream temperature were positively
related to solar radiation and negatively related to discharge. Frequent
precipitation during the summer monsoon season produced moderate
increases in discharge (from 1 to 5 mm day-1), which mitigates stream
temperature increases associated with solar radiation. Catchment
hydrologic response to rain events can play an important role in
controlling stream thermal response to forest management practices.