Climate warming alters fuels across elevational gradients in Great Basin bristlecone pine-dominated sky island forests

Abstract

Little is known about fuel characteristics and dynamics in GBBP communities, and current monitoring programs inadequately quantify the surface and canopy fuels of this system. Using the Forest Inventory Analysis (FIA) plot variables of tree species, height, diameter at breast height (DBH), canopy base height (CBH), coarse (CWD) and fine (FWD) woody debris counts, and canopy fuels measurements, this paper examines the effects of climate-induced changes to fuel loading, fire hazard and risk on predicted changes in fire behavior and severity. Field transects were installed using FIA protocols along environmental gradients. Plots were located every 22 chains or ∼440m along random transects on Mt. Washington in the Great Basin National Park (GBNP) and in the nearby Mt. Moriah Wilderness, NV. Additional plots were installed at Notch Peak (UT), Cave Mountain (NV), and Wheeler Peak (GBNP, NV). Linear regression showed that all classes of FWD decreased with elevation, and only 1000-h fuels remained constant across elevational transects. This, combined with lower CBH and foliar moisture and increasing temperatures due to climate change, increases fire potential at the Great Basin bristlecone pine treeline, threatening the oldest individuals of this iconic species. New information about discontinuous fuels will aid in management of high elevation alpine treeline forests.