PARENT SESSION
Poster Session #40: Urban Ecology.
Thursday, August 9, 2001. Presentation from 3:30 PM to 5:00 PM. Exhibition Hall

Effects of mycorrhizal associations on urban tree carbon storage potential.

Stabler, Linda¹, Martin, Chris¹, Stutz, Jean¹, ¹

ABSTRACT- Field and greenhouse studies were conducted to test how urbanization might affect arbuscular mycorrhizal fungal (AMF) associations and urban tree carbon sink potential in the Phoenix, Arizona metropolitan area. Soil samples and roots were collected from the rhizosphere of trees at three remnant Sonoran Desert sites and at three drip irrigated, residential sites to determine degree of root colonization, examine AMF spores present, and to produce inocula for greenhouse studies. Greenhouse experiments were used to evaluate growth, CO₂ assimilation, root respiration, and phosphorus status in three urban tree species relative to uninoculated controls. Trees at desert sites were more highly colonized by AMF than those at residential sites and fungal species composition differed between the two site types. AMF increased growth of Acacia and Fraxinus and assimilation in Acacia. Root respiration was highest in uninoculated controls for Acacia and Fraxinus. Estimated increase of carbon storage due to colonization by the desert AMF population was 95 and 51 per cent for Acacia and Fraxinus, respectively. No AMF treatment effects were seen in Parkinsonia. Based on these data, we conclude that AMF might significantly increase urban tree carbon storage, depending on tree species and edaphic conditions.

KEY WORDS: AMF, phosphorus, CO2, photosynthesis