Determining juvenile-mature wood transition in Scots pine using latewood density

摘要

Segmented regression models were applied successfully to estimate the cambial age of juvenile-mature wood transition in Scots pine (Pinus sylvestris) sample trees from slow-grown stands. Mean ring density, and earlywood and latewood density profilesfrom 99 trees were determined by X-ray densitometric analysis of disks taken at 4-m stem height. The cambial age of transition from juvenile to mature wood is described according to segmented regression models based on latewood density profiles. The time series nature of the density data was considered by using generalized nonlinear regression and restricted maximum likelihood regression procedures. The quadratic-linear fit shows the transition at cambial age of about 22 with a standard deviation of 5to 7 yr. Segmented regression models are an effective tool to get objective estimates of the juvenile-mature wood transition from density profiles.