Date of Graduation

Spring 5-13-2014

Document Type

Project/Capstone

Degree Name

Master of Science in Environmental Management (MSEM)

Department/Program

Environmental Management

First Advisor

Gretchen C. Coffman

Abstract

Methods of dendrochronology by means of incremental coring

have been refined in this study for specific use in northern

California riparian floodplains. Little information is available

on riparian dendrochronology because of the challenges of

analyzing riparian tree species. Three dominant tree species

(Alnus rubra, Umbellularia californica, Acer macrophyllum)

in the floodplain of Redwood Creek were evaluated for the

relationship between age and diameter at breast height (DBH)

using a least squares linear regression analysis. Through this

study, complications with analysis for the riparian tree species

led to a more thorough investigation as to enhancing core

quality and annual growth ring visibility. As methods of coring

and ring enhancement were refined, core quality and analysis

improved. The correlation of determination for both red alder

and California bay laurel were strong (R2= 0.957; R2= 0.982,

respectively). Strong R2 values suggest DBH can be determined

for red alder and California bay laurel using the specific linear

regression equations for each species. Linear regression model

of Bigleaf maple had a lower correlation determination value

(R2=0.452). Big leaf maple regression models may increase in

R2 value with more sampling. Linear regression equations for

these red alder and California bay laurel are suitable across

the watershed to simplify dendrochronology by requiring only

measured diameter of trees. Regression equations from this

study informed restoration planning of the age floodplains in

the lower reaches of the Redwood Creek watershed, obviating

other more destructive and expensive means of dating habitat.

Future restoration projects in this watershed may apply this

refined method for these species to gather pertinent historical

information of environmental conditions. The equations may

also be applicable to red alder and California bay laurel in other

watersheds with similar environmental conditions, requiring only

a few tree core samples to determine applicability. The refined

dendrochronology method may also improve tree coring of other

tree species with similar wood anatomy.