Primary productivity and resource use in Metrosideros polymorpha forest as influenced by nutrient availability and Hurricane Iniki

Primary productivity and resource use was measured in montane Metrosideros polymorpha forest across a 4.1 x 10^6 year chronosequence where available pools of soil nitrogen and phosphorus varied with site age. At the oldest site, N, P and a mix of other essential nutrients applied in complete factorial combination to 32 plots demonstrated P limitations to above-ground net primary productivity (ANPP) as predicted by conceptual models of soil development and weathering. This in contrast to N limitations previously demonstrated in geologically young soils. The response to P was that of an initial increase in photosynthetic area followed by increased wood production. Following hurricane Iniki, leaf area index (LAI) was reduced by 3% to 58%, but recovered to near pre-hurricane values by nine months. Live fine root mass was reduced by 44%, was not related to reductions in LAI, and took two years to recover. Stem damage was largely that of branch removal but some stems were tipped or snapped and large trees were damaged with greater frequency than small trees. Fine litterfall was 1.4 times the annual input while nutrient transfers from the canopy to forest floor approximated that of a typical year. During litter decomposition there was an initial mass loss of nutrients from both leaves and twigs, followed by immobilization of N and P. Stem growth and ANPP decreased for a year and then recovered to near pre-hurricane values. Both ANPP and production per unit leaf area increased in response to increased P availability. Across the chronosequence, primary productivity was greatest where available pools of soil N and P were greatest, but differences between sites were small and there was no consistent pattern for above- versus below-ground allocation. M. polymorpha within a site appears to adjust to N and P availability by increasing radiation conversion efficiency (RCE) when nutrient availability is relatively high and by increasing nutrient use efficiency (NUE) when availability is low. A negative correlation between RCE and foliar nutrient resorption supports the idea that a tradeoff exists between RCE and leaf characteristics affecting NUE.

Grantor dc:publisher

University of Hawaii at Manoa

Year dc:date.issued

1995

Author dc:creator

• Herbert, Darrell Anthony

• Ohia lehua
• Soils--Nitrogen content
• Soils--Phosphorus content
• Hurricane Iniki (1992)

Statement dc:rights

• All UHM dissertations and theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission from the copyright owner.

Language dc:language

eng

Handle dc:identifier.uri

http://hdl.handle.net/10125/9272

OAI record oai:identifier

https://scholarspace.manoa.hawaii.edu/dspace-oai/request?verb=GetRecord&metadataPrefix=dim&identifier=oai%3Ascholarspace.manoa.hawaii.edu%3A10125%2F9272