Environmental science seniors and instructor at Griffith Park

The first graduating class in the Environmental Science major spent a good deal of the Spring Quarter 2008 on the ashy slopes of L. A.’s Griffith Park. A major brush fire had incinerated some 817 acres on May 8, 2007 and exposed the Hollywood and Los Feliz neighborhoods to potential mudslides and flooding during the 2007/08 rainy season. In October 2007, over 400 burnt acres were sprayed with hydromulch, a mixture of wood fibers and tackifiers (guar gum and copolymers acting like a glue) to stabilize the slopes and hold the soil in place.

As part of the senior Environmental Practicum (Env 180) the class of ten students formed four research teams to study the impacts of this chaparral fire on the hilly ecosystem of the SE portion of Griffith Park; the city’s Park and Recreation Department supported this effort. Due to an almost total lack of rain in the late winter and spring no major mudslides materialized. The vegetation, however, had shown signs of resprouting and germination of long dormant seeds. Three of the teams decided to assess the effects of the carpet-like hydromulch on plant succession of native species and introduced weeds such as black mustard and castor bean. Experimental study plots and nearby control plots were delineated and analyzed throughout the spring. The results were somewhat disappointing because of the unusually dry weather from February through June; some plots from the hydromulched slopes showed no sprouting at all while others provided some evidence of suppression of postburn plant succession compared to non-hydromulched slopes. The fourth team focused on fire-induced water-repellent soil layers on slopes near the Griffith Park Observatory. Near graduation time, the seniors presented their research projects during a public lecture at the IoE.

Published: Friday, August 22, 2008

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