Organic matter changes in an age series of Pinus radiata plantations [in Australia.
Data are given on the above-ground biomass of trees, ground flora and litter for a series of young P. radiata plantations 3, 5, 7, 9 and 12 years old at Tumut, New South Wales. The weights of trees in the stands were determined by means of regression equations relating tree weight to stem diameter and length. From the biomass data, the production, retention and decomposition of organic matter were calculated. A comparison between the values obtained and those for other Pines shows that P. radiata is a very efficient producer of organic matter. The early occurrence (5-7 years after planting) of maximum production of organic matter reflects the rapidity with which maximum leaf weight is achieved. KEYWORDS: Pinus radiata increment \ yield weight \ Pinus radiata production, biological \ Production biological aerial part \ stand \ Production biological determination \ Production biological interspecific variations