Fire and Invasive Annual Grasses in Western Ecosystem
A project funded by the Joint
Fire Science Program
Intensive field experiments are being used to monitor changes after fire
in levels of nitrogen (N) and phosphorus (P) (and light in the Sierra Nevada),
and the effects of these changes on the productivity of invasive annual
grasses. Variations among burning seasons and fuel levels create a realistic
range of fire intensities within each ecoregion. Evaluating these variations
will provide a basis for creating broad generalizations about the effects
of various burning conditions in each ecoregion. These experiments will
also allow us to validate
results from the laboratory studies.
Objectives
- Evaluate the role of elevated and reduced N and P on bromegrass and native species growth
- Contrast different fuel loads on fire intensity with postfire levels of soil nutrient availability
- Correlate soil heating profiles with fuel loads used in field experiments for calibration of greenhouse experimental results
- Determine soil nutrient (N, P, Carbon, Potassium) changes associated with all burning treatments
- Evaluate the role of soil types (carbonate vs. non-carbonate) in arid and semi-arid shrublands on bromegrass response to fire and nutrients
- Evaluate the role of elevated solar radiation levels from high crown scorch in forested ecosystems on bromegrass response to fire and nutrients
- Determine the extent to which fire season may control bromegrass establishment
- Evaluate the effects of fire on cheatgrass (Bromus tectorum) and red brome (Bromus madritensis spp. rubens)
Study Design
Soil temperatures are monitored at 3 levels from the soil
(-2,2,5cm)
during burns. Plants will be monitored for percent ground surface cover
by each species and height and areal diameter of a random subsample of
individual plants for 3 years postfire. Soils are being collected for
2 years postfire and will be monitored for content of Carbon, Nitrates,
Ammonia, Phosphate, pH in all ecoregions as well as calcium carbonate
for desert soils.
Great Basin Sagebrush Steppe and Mojave Desert Scrub |
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| Postfire Manipulation | Fire Treatments |
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| Unmanipulated Control | Unburned | Spring Burn | Summer/Fall Burn |
| Nitrogen Addition | Unburned | Spring Burn | Summer/Fall Burn |
| Phosphorus Addition | Unburned | Spring Burn | Summer/Fall Burn |
| Carbon Addition | Unburned | Spring Burn | Summer/Fall Burn |
| Carbonate Addition | Unburned | Spring Burn | Summer/Fall Burn |
| Fuel Addition | Unburned | Spring Burn | Summer/Fall Burn |
Sierra Nevada Yellow Pine Forest |
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| Postfire Manipulation | Fire Treatments
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| Unmanipulated Control | Unburned | Spring Burn | Summer/Fall Burn |
| Nitrogen Addition | Unburned | Spring Burn | Summer/Fall Burn |
| Phosphorus Addition | Unburned | Spring Burn | Summer/Fall Burn |
| Carbon Addition | Unburned | Spring Burn | Summer/Fall Burn |
| Carbonate Addition | Unburned | Spring Burn | Summer/Fall Burn |
| Fuel Addition | Unburned | Spring Burn | Summer/Fall Burn |
| Half-Full Sunlight | Unburned | Spring Burn | Summer/Fall Burn |
| Cheatgrass Seed Addition | Unburned | Spring Burn | Summer/Fall Burn |
| Native Seed Addition | Unburned | Spring Burn | Summer/Fall Burn |
URL http://www.werc.usgs.gov/fire/lv/fireandinvasives/
field_experiments.htm Contact: Webmaster Last Modification: July 21, 2004 |
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