One hundred and fifty years later, visitors to this border regionbetween California and Nevada still marvel at Lake Tahoe, but sadlythe “jewel of the Sierra” is not the same gem it was inTwain’s time. Boating on the lake during his trip, Twain said hecould see rocks at least 80 feet below the surface — a degree ofclarity that scientists attribute to “ultra-oligotrophic”conditions, meaning exceptionally nutrient-poor and pure. Since the1960s, however, Lake Tahoe’s renowned water quality has been inslow decline, and exactly why “is the $64,000 question,”says soil scientist Dale Johnson of the University of Nevada inReno. Damaging blazes sweep the Tahoe region regularly, and by the timeJohnson teamed up with his University of Nevada colleague, WallyMiller — an expert on Tahoe’s water quality — scientists alreadyknew how catastrophic fires could affect downstream streams andlakes. Sierra Wireless Router
Wildfire can leave slopes bare of vegetation and unprotectedfrom erosion. Burning also releases nitrogen, phosphorus, sulfate,and other biochemicals locked in plants, wood, and soils, allowingthe nutrients to run off downslope or seep into groundwater. Butwhen Miller and Johnson began their studies, they discoveredsomething that few, if anyone, had suspected: Not only could amajor disturbance like fire affect Lake Tahoe, but so too could alack of disturbance — the absence of fire. “The results werevery surprising and therefore very hard to publish,” Johnsonsays. “No one believed it.” But the findings also lead to a dilemma. China Mini 3G Module
On one hand, wildfire isbeneficial in that it burns away decades of accumulated organicmaterial, which Johnson and Miller have shown can potentially be aslow but significant source of nutrients to Lake Tahoe. On theother hand, severe wildfire can also deplete forests of nitrogenand send pulses of nutrients downstream — not to mention thedamage it does to timber and private property. “So what do you do?” Miller asks. The answer latelyembraced by forest managers is to mimic the natural, Sierran fireregime that existed before aggressive fire suppression began.Managers will purposely light small, controlled fires to burn awayaccumulated woody debris. Huawei WiFi Router Manufacturer
Or they’ll remove wood with harvestingequipment or chip it on site. But managers don’t want to remove too many nutrients from thesystem, since they’re needed to support future generations oftrees. So Miller and Johnson have been studying the practices’impacts on nutrients and on water quality, just as they earlierinvestigated catastrophic wildfire and fire suppression.