Ecology–Soil Relations — Abstract of Paper


Seasonal and Site Effects on Oak Fine Root Production and Ectomycorrhizal Colonization in California Oak Woodland
Xiaomei Cheng¹ and Caroline S. Bledsoe¹


At three sites in a blue oak woodland in northeast California, we studied seasonal patterns of blue oak (Quercus douglasii Hook and Arn.) fine root (< 2 mm diameter) production and ectomycorrhizal (ECM) colonization using root ingrowth cores. In a short-term study, ingrowth cores were installed and harvested in 3-month intervals for one year. Oak fine root production was lower in fall and winter, higher in spring, and intermediate in summer. ECM roots were found only in spring and fall. In a long-term study, ingrowth cores were installed in January 1998 and harvested after 6, 9, 12 months, respectively. ECM colonization was higher after the 6-month (winter, spring) interval, lower after the 9-month (winter, spring, summer) interval and intermediate after the 12-month (winter, spring, summer, fall) interval. Both long-term and short-term studies demonstrated that ECM fungi were active in spring and fall seasons. ECM colonization was much higher in an undisturbed six-month interval (winter + spring, long-term study) than in a disturbed 6-month interval (winter + spring, short-term study), suggesting that disturbance decreased mycorrhizal colonization.