Biogeochemistry of beetle-killed forests: Explaining a weak nitrate response
2013 (English)In: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 110, no 5, 1756-1760 p.Article in journal (Refereed) Published
A current pine beetle infestation has caused extensive mortality of. lodgepole pine (Pinus contorta) in forests of Colorado and Wyoming; it is part of an unprecedented multispecies beetle outbreak extending from Mexico to Canada. In United States and European watersheds, where atmospheric deposition of inorganic N is moderate to low (<10 kg.ha.y), disturbance of forests by timber harvest or violent storms causes an increase in stream nitrate concentration that typically is close to 400% of predisturbance concentrations. In contrast, no significant increase in streamwater nitrate concentrations has occurred following extensive tree mortality caused by the mountain pine beetle in Colorado. A model of nitrate release from Colorado watersheds calibrated with field data indicates that stimulation of nitrate uptake by vegetation components unaffected by beetles accounts for significant nitrate retention in beetle-infested watersheds. The combination of low atmospheric N deposition (<10 kg.ha.y), tree mortality spread over multiple years, and high compensatory capacity associated with undisturbed residual vegetation and soils explains the ability of these beetle-infested watersheds to retain nitrate despite catastrophic mortality of the dominant canopy tree species.
Place, publisher, year, edition, pages
2013. Vol. 110, no 5, 1756-1760 p.
nitrogen biogeochemistry, streamwater chemistry, nitrate loss, watershed disturbance
IdentifiersURN: urn:nbn:se:uu:diva-196557DOI: 10.1073/pnas.1221029110ISI: 000314558100041OAI: oai:DiVA.org:uu-196557DiVA: diva2:610801