YUBA COUNTY WATER AGENCY Relicensing Website

Study 6.2, Riparian Habitat Downstream of Englebright Dam, requires study-specific consultation with Relicensing Participants on where (strata) and how many cottonwood cores will be taken with the goal of understanding the conditions under which the existing cottonwood stands became established. The following list identifies the methods for core sampling stratification to be considered during the June 5, 2012 consultation:

 

• Trees will be selected for coring in order to scale the sampling to variable growing conditions on the Yuba.
• Diameter at breast height (DBH) will be the basis for stratifying coring samples by quantiles. The breaks between strata will be the 40th, 70th, and 85th quantiles within each site, based on the field inventory. 
• No more than 10% of the trees in each quantile will be selected for sampling using a random number table or other randomizing method.
• Trees selected for coring will be sampled in the field.
• One core will be collected per tree unless the core fails to reach near the pith (failure to reach the first year could be due to the pith not being in the center of the tree or the tree being hollow).  In the latter case, the bit will be repositioned, and a second core collected.

The phone conference will be held from 9:00 AM to noon.  Relicensing Participants will discuss the cottonwood coring stratification method identified above.  Please call (866) 994-6437, Conference Code 221 4051.