Effect of nitrogen supply on net primary production in Corsican Pine.
Reports further studies in the stand of Pinus nigra var. maritima already described [see preceding abstract]. Net primary production of the Pine was not affected by application of N during the first year of treatment (1964) although needle retention was increased. In the following years (up to 1967), application of more than or equal to 168 kg N/ha/year doubled net primary production and also stemwood formation, which was at a maximum for dosages of 168 and 336 kg N/ha/year. The increase in production was due to greater needle area and also to an increase in net assimilation rate.