Responses of two Pinus species to varying atmospheric CO{sub 2}, air temperature and soil N availability
- Duke Univ., Durham, NC (United States)
Experiments that test interactive effects of multiple environmental factors should furnish the most realistic predictions of plant response to future environments. In this study, a fast growing species, loblolly pine (Pinus taeda), and a slow growing species, ponderosa pine (Pinus ponderosa), were compared for 160 days at two CO{sub 2} levels (35 Pa and 70Pa), two air temperatures (seasonal mean and seasonal mean +5 C), and two nitrogen treatments (1 mM NH{sub 4}NO{sub 3} and 5 mM NH{sub 4}NO{sub 3}) in the Duke University Phytotron. Biomass production was much greater in loblolly pine than in ponderosa pine but both species responded strongly to CO{sub 2} enrichment (p + 0.0001). In loblolly pine, there was a significant CO{sub 2} x Temperature interaction (p = 0.035) on biomass accumulation, where the 5 C increase in temperature inhibited growth in low CO{sub 2} (-13%) but stimulated growth in elevated CO{sub 2} (27%). Although growth of loblolly pine was significantly reduced by low N availability, there was not a CO{sub 2} x N interaction on biomass accumulation of loblolly pine suggesting that low N did not limit the response to CO{sub 2}. Biomass allocation of loblolly pine was affected by N and temperature; low N increased biomass allocation to roots (14%) and high temperature increased the ratio of stem mass to branch mass (30%). Neither temperature nor N had an effect on biomass accumulation or allocation of ponderosa pine. In ponderosa pine, elevated CO{sub 2} stimulated biomass allocation of roots (18%) and the ratio of branch mass to stem mass (62%). This study suggests that both pine species are sensitive to increases in atmospheric CO{sub 2} even in forests moderately low in soil N availability. Further, future warming may interact with elevated CO{sub 2} to stimulate biomass production of loblolly pine.
- OSTI ID:
- 107142
- Report Number(s):
- CONF-9507129-; ISSN 0012-9623; TRN: 95:006512-0058
- Journal Information:
- Bulletin of the Ecological Society of America, Vol. 76, Issue 3; Conference: 80. anniversary of the transdisciplinary nature of ecology, Snowbird, UT (United States), 30 Jul - 3 Aug 1995; Other Information: PBD: Sep 1995
- Country of Publication:
- United States
- Language:
- English
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