Effects of Climate Variability and Accelerated Forest Thinning on Watershed-scale Runoff in Southwestern Ponderosa Pine Forests
Media Type: Webinar
Distribution Contact(s):
  • Southwest Fire Science Consortium
Recording Date: April 15, 2015

Cataloging Information

Arizona; climate variability; drought; Pinus ponderosa; ponderosa pine; resilience; runoff; SWFSC - Southwest Fire Science Consortium; thinning; water; webinars; yield
Record Maintained By:
Record Last Modified: August 23, 2017
FRAMES Record Number: 19676


The recent mortality of up to 20% of forests and woodlands in the southwestern United States, along with declining stream flows and projected future water shortages, heightens the need to understand how management practices can enhance forest resilience and functioning under unprecedented scales of drought and wildfire. To address this challenge, a combination of mechanical thinning and fire treatments are planned for 238,000 hectares (588,000 acres) of ponderosa pine (Pinus ponderosa) forests across central Arizona, USA. Mechanical thinning can increase runoff at fine scales, as well as reduce fire risk and tree water stress during drought, but the effects of this practice have not been studied at scales commensurate with recent forest disturbances or under a highly variable climate. Modifying a historical runoff model, we constructed scenarios to estimate increases in runoff from thinning ponderosa pine at the landscape and watershed scales based on driving variables: pace, extent and intensity of forest treatments and variability in winter precipitation. We found that runoff on thinned forests was about 20% greater than unthinned forests, regardless of whether treatments occurred in a drought or pluvial period.

Recording Length: 0:48:51
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