Disturbance Vectors by Bryan Petit, CUF Program Manager USDA, Natural Resources Conservation Service
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Disturbance Vectors by Bryan Petit, CUF Program Manager USDA, Natural Resources Conservation Service Overview Monsoonal 9 SpeciesSystem of Trees ¾ Average annual ¾ rainfall 3 oaks > 40 in./yr 3 pines ¾ More than 80% of occurs ¾ rainfall incense -cedar ¾ between white fir December and March. ¾ bigcone Doug-fir Cyclic Discussion In various locations around San Diego County ½ Stuff you know ½ Stuff you should be looking at The Year is 2000 From Savanna to Understory Reinitiation Overstock from fire suppression Water-driven vs. Light-driven systems 2001, 2002, 2003: Drought Three worst years in recorded history # of trees Disturbance event removes young trees Results in major die off 1,080,000 – 1,230,000 dbh Stand Characteristics Dead trees in FAST area Average Fuel Average FuelMoisture Moisture Scolytus during duringCedar CedarFire: Fire: 11Hr Hr––1% 1% 10 10Hr Hr––2% 2% 100 100Hr Hr––4% 4% Palomar Mountain Western pine 1000 Hr – beetle 9% 1000 Hr – 9% Ips Bark Beetle Activity Rain and Fire Perturbed Oaks Originally in savanna stands Proximity to streams Armillaria & unknown pathogen explosion The Issue of Scale Zooming in / Scaling Down More important to “zoom out” Vegetation Belts White Fir Range Map Type Conversion As stands convert, we convert Requires frequent low-level disturbance Vegetation Site Defensible Space Climate Conclusion Stand dynamics in conversations yields good perspective.
