1. Nitrogen Utilization by Saprophytic Fungi in a Managed Forest Ecosystem Brian Strahm

2. Introduction “Under the silent, relentless chemical jaws of the fungi, the debris of the forest quickly disappears…” -A. Forsyth and K. Miyata, Tropical Nature NITROGEN limiting nutrient for plant and microbial growth FUNGI decomposers of soil organic matter DECOMPOSITION releases nutrients back into the environment

3. Fall River LTSP Study Pacific County, WA Weyerhaeuser - McDonald Tree Farm Treatments: Conventional Bole Only Total Tree Plus

4. Treatments 2nd Generation Douglas-fir Forest (~ 47 years old) Bole Only Total Tree Plus

5. Methods Malt Extract Nitrogen Substrates

6. Organic Nitrogen: Aspartate - chain structure; single N Arginine - chain structure; multiple N Proline - ring compound; single N Inorganic Nitrogen: Sodium nitrate - Na + NO 3 - Ammonium chloride - NH 4 + Cl - Ammonium nitrate - NH 4 + NO 3 - Amino acids Ions in solution

7. Organic Substrates Aspartate Arginine Proline

8. Inorganic Substrates nitrogen oxygen Nitrate (NO 3 - ) nitrogen hydrogen Ammonium (NH 4 + )

9. Results

10. Results

11. Results

12. Results

13. Conclusions Environmental Homogeneity and Specialization Forest Stand: Heterogeneous environment No particular substrate specialization Bole Only: Increasingly homogeneous environment Trend toward utilization of inorganic nitrogen Total Tree Plus: Homogenous environment Strongest prevalence for inorganic nitrogen Proline / Pathogenic fungi?

14. Thanks Tina Jensen Marianne Elliott

15. References Edmonds, R.L., Thomas, T.B, Rhodes, J.J. 1991. Canopy and soil modification of precipitation chemistry in a temperate rain forest. Soil Science Society of America Journal 55: 1685-1693. Gebauer, G., Taylor, A.F.S. 1999. 15 N natural abundance in fruit bodies of different functional groups of fungi in relation to substrate utilization. New Phytology 142: 93-101. Osono, T., Takeda, H. 2001. Organic chemical and nutrient dynamics in decomposing beech leaf litter in relation to fungal ingrowth and succession during 3-year decomposition processes in a cool temperate deciduous forest in Japan. Ecological Research 16: 649-670. Sharples, J.M., Cairney, J.W.C. 1997. Organic nitrogen utilization by an unidentified mycobiant isolated from mycorrhizas of Pisonia grandis. Mycol. Res. 101: 315-318. Yamanaka, T. 1999. Utilization of inorganic and organic nitrogen in pure cultures by saprophytic and ectomycorrhizal fungi producing sporophores on urea-treated forest floor. Mycol. Res. 7: 811-816.