a significant agency concern, and has always been encouraged by the agency, citing published TRPA regulations, public documents, and previous public hearings. However, in post fire hearings stating this position, those that lost their homes were so infuriated that security escorts were required to protect TRPA Staff's exit. Prompted by local newspaper articles quoting allegations of TRPA staff forcing homeowners to pile dry pine needles and other flammable materials around their homes, and even up against the structures, creating dangerous fire hazards, state and local politicians reacted swiftly by calling for investigations into TRPA policies and staff misconduct. In July 2007, California and Nevada governors Arnold Schwarzenegger and Jim Gibbons signed a bi-state "Blue Ribbon Fire Commission" agreement, to investigate fire issues in the Lake Tahoe basin, including TRPA regulations that caused problems that led to the loss of hundreds of structures. While not meeting the legal threshold of staff misconduct and detrimental agency policies, the U.S. Forest Service fire investigations in the Angora Fire investigations confirmed that most of the structures caught fire from "firebrands"—pieces of burning wood—carried in the smoke column either from neighboring structures or from nearby burning vegetation. The investigations found that a few older homes had highly flammable wooden shake roofs and inadequate fire clearance around the structures. In some cases, winter fire wood and kindling supplies were piled too close to homes. The study did state that dead and dying vegetation along Angora Creek "likely contributed" to the fire's rapid spread. Native riparian vegetation in "stream environment zones" (such as Angora Creek) in the Tahoe Region are protected as sensitive resources, and removal of vegetation from these areas is vigorously restricted by TRPA to protect damage to soils, habitat, and water quality. While fire investigators have concluded that several factors contributed to the disastrous fire, including unburned piles from previous forest thinning projects, lack of defensible space, stockpiling of flammable materials near structures, and thick ground covers, investigators found that several structures actually burned the surrounding vegetation—not the reverse. There is continuing disagreement regarding ground cover within of structures. In certain cases, TRPA regulations require ground cover to provide protection from soil erosion on disturbed soil. Ground cover may often be lawn or other landscaping, however site-specific native vegetation, or naturally occurring forest litter such as a thin layer of pine needles or wood chips, is generally the environmentally preferable alternative, and is more