DIFFERENCES IN ROOT LONGEVITY OF SOME TREE SPECIES

Although the importance of root production and mortality to nutrient f luxes in ecosystems is widely recognized, the difficulties associated with root measurements have limited the availability of reliable data. We have used minirhizotrons and image analysis to measure root longev ity of Prunus avium L., Picea sitchensis (Bong.) Carriere, Acer pseudo platanus L. and Populus x canadensis cv. Beaupre directly in cohorts o f roots. Major differences in the longevity of roots among species wer e identified. For example, 40% of Prunus avium roots but only 6% of Pi cea sitchensis roots survived for more than 14 days. Survival analysis of cohorts of roots of Prunus avium and Populus x canadensis revealed differences in the distribution of longevity among cohorts. Genetic, biotic and abiotic factors that may influence longevity are discussed.