Do genetic improvements in radiate pine seedlings confound their use as indicators of change in soil quality?

In a glasshouse environment, and in field trials with trees up to four year s of age, the effect of genetic improvement on the early nutrition and grow th of radiata pine was examined. In the glasshouse trial, on a range of for est soils, there was no effect of genetic gain (expressed as growth and for m rating) on either seedling biomass or nutrient content; in field experime nts, correlations between genetic gain (breeding value and growth and form rating) and growth (height, root collar diameter, or both) became: apparent from Age 2 years at both sites. It was concluded that the genetic improvem ent of radiata pine seedlings would not be needed to be taken into account if seedlings were to be used before the age of six months as 'bio-assay' in dicators of changes in soil quality. (C) 1999 Elsevier Science B.V. All rig hts reserved.