Coastal Forests of the remote Cordillera Piuchue in southern Chile have not been disturbed by agriculture or logging and receive very little nitrogen in precipitation. We measured N-mineralization and productivity in three types of forest for one year, and fertilized plots in two of the forests for 3 years. Annual net N-mineralization was very low (1-2 kg/ha) in the montane conifer and montane broadleaf forests respectively, and substantially higher (24 kg/ha)in the broadleaf-dominated forest near sea level. Litterfall lignin:N ratio was the major control on N-mineralization. The montane forests had very high lignin:N ratios (50:1 and 80:1)compared to similar N. American forests, accounting for the very low levels of N-min. Unlike cool temperate northern hemisphere forests with very low N-min rates, productivity of these plots was moderate to high (avg 9 kg/ha-yr)and N requirement was many-fold higher than measured N-min in the montane forests. N-fertilizer (as ammonium bicarbonate) was added at annual rates 2X the annual requirement in montane conifer and montane broadleaf forest plots. After 3 years of N additions, one species in the broadleaf-forest plots (Drymis winterii) responded with greater wood production, but there was no response to mineral N added in the montane conifer forest. Either the trees in these forests are effective competitors for N released from SOM or they acquire most of their N via alternate pathways which have not been well-studied.
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