Adjustment of estimated tree growth rates in northern California conifers for changes in precipitation levels

Even with similar initial conditions, observed forest growth rates on perma nent sample plots in the conifer region of northern California differ for d ifferent periods. Thus, individual-tree growth models built with growth par ameters estimated from data from one period may not produce accurate estima tes for another period unless some allowance is made for this variation in growth rates. Variation in growth rates of northern California conifers thr ough time has been shown to be correlated with precipitation changes. A met hod is presented that adjusts periodic growth estimates for variation in pr ecipitation between periods. This provides a basis for adjusting short-term growth data for making long-term growth projections. Perhaps more importan tly, short-term inventory updates might be made more accurately.