Large wood (LW) creates channel diversity and important habitat for salmonids (Oncorhynchus spp.) and other riverine organisms.  Generally, trees must be greater than 1 m in length and 0.1 m in diameter before they play an effective geomorphic role.  However, attaining a large diameter in a riparian zone altered by frequent channel movement requires rapid growth rates. We examined two related questions: 1) Are higher rates of nitrogen mineralization associated with an increase in tree diameter growth? 2) Does soil nitrogen availability (estimated through mineralization rates) change as stands age?  To answer these questions, we measured total nitrogen mineralization rates for 23 permanent plots (varying in age from <15 yrs to >200 yrs) along the Queets River, Washington.  

Results/Conclusions

Preliminary results suggest that tree ring width, measured from cores taken from the 10 dominant trees in each of the 23 plots, is significantly different between plots of different ages (p<0.001).  We will present additional data on soil nutrient availability and tree growth to determine the effects of soil nutrient conditions on riparian tree growth.