Smoke-Cued Emergence in Plant Species of a Ponderosa Pine Forest: Contrasting Greenhouse and Field Results Scott R. Abella University of Nevada Las Vegas School of Life Sciences

Introduction  Importance of seed germination  Seed exposure to smoke  Smoke-stimulated germination  Butenolide compound 1 1 Flematti, G.R., et al A compound from smoke that promotes seed germination. Science 305:977.

Introduction  Fire effects, smoke technology  Seed, seed bank, field research  Many factors could affect response  Most field research in Australia  Mixed results

Objective  Frequent-fire ponderosa pine forests  Determine effects of smoke at 3 scales: (i) seed, (ii) seed bank, (iii) field  Grazing interaction in field experiment

Methods Seed Experiment 61 native species Liquid smoke applied to soil Seed Bank Experiment 9 sites, 2 plots per site averaged 0-5 cm mineral soil 10-month emergence period

Field Experiment 9 thinned sites, two 20 × 25 m plots Regen Direct (Forest Flavors, Inc.) 10 m 2 exclosure and paired area open to grazing on each plot Split-plot design with covariate Pre-tmt, 15 months post-tmt

Results Seed Experiment Overall positive effect, no neg. effect Promoted 5/8 Penstemon (P < 0.01) Penstemon barbatus Error bars = 1 SD USDA Plants Database

t = -2.56, P = 0.03 t = -2.41, P = 0.04 Seed Bank Experiment 67% increase of emergents 60% increase in richness

Seed Bank Experiment Smoke results in general increase Composition (MRPP, P = 0.36) Relative seed density (%) Control Smoke Erigeron flagellaris Erigeron divergens 5 7 Carex geophila 4 5 Muhlenbergia montana 0 1

(b) 9 m 2 No. species (b) Richness/m 2 No. species (a) 1 m 2 Field Experiment Split-plot analysis of cover, richness Smoke P = Interaction NS Grazing P = Covariate Sig. C c c aaaaaaaaa

Ordination, Sørensen comparison No effect on community composition

Discussion  Study limitations – e.g., variable seed genetic sources greenhouse conditions  Smoke enhanced emergence in seed and seed bank greenhouse experiments, but not in field experiment

Field outcome smoke application rate – within range of Australian studies of varying outcomes timing: June application corresponded to historical fires Precip: 112% in 2005 tmt year, 72% 2006 post-tmt but July-Aug 128%

Field outcome Seed bank composition – Penstemon uncommon Time since fire 1 Other cues Thinning 1 Van Horne and Fulé Comparing methods of reconstructing fire history using fire scars in a southwestern United States ponderosa pine forest. CJFR 36:

Smoke only one component of fire Heat 1, pine charred wood 2 Fire cues relative to altered post- fire/thinning environments 1 Huffman, D.W West. North Am. Nat. 66: Abella, S.R., et al CJFR 37: Uses: Seed bank assays Pre-tmt of seeds

Acknowledgments Sam Crace (“Charcoal Sam”), Forest Flavors, Inc., Kentucky, donated Regen Direct Judy Springer, Kyle Christie, Brian Zimmer, and students/staff at NAU ERI for help with fieldwork Don Normandin, Matt Tuten, and Luke Brandy installed exclosures Brad Blake and Phil Patterson, NAU research greenhouse J.J. Smith, Keith Pajkos, and NAU Centennial Forest Wally Covington and the NAU ERI