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Douglas Encroachment

Siah Baakoi, Anais Wilson, Bailey Berens, and Alexa Ancheta

Does encroachment pose an impending problem at the Fairfield Osborn Preserve?

SCI 120 Background I • woodlands struggle to recruit with a number of health threats (UC Oak Woodland Management) • Encroachment is the overwhelming advancement of a on a given area

Coast Coastal Douglas Oregon White Oak ● Height: 20 - Fir ● Height: 50 - 40 feet (in ● Height: 250 80 feet some cases feet ● Shade 80 feet) ● Shade Tolerance: ● Shade Tolerance: Intermediate Tolerance: Intolerant as as a seedling, Throughout seedling, intolerant in life intermediate adulthood ● tolerance in ● adulthood and drier sites ● Evergreen Background II • Since Douglas are disproportionately larger than oaks, their saplings out compete the oak saplings (UC Agriculture and Natural Resources)

• Two species most affected by encroachment: Oregon White Oak and California Black Oak (Science Update, 2010)

• Very crucial to our woodlands ecology

• There is a documented loss of 30% of White oak woodland by Douglas Fir encroachment since 1850 (Sugihara and Reed) Hypothesis

We believe that Douglas Fir will pose an impending problem at FOP because there will most likely be a large enough group of Douglas Firs that are past easy removal along with the rain creating moist soil that the Douglas Fir thrive in increasing likeliness of encroachment. Methods

• Went to two sites that had Douglas Firs present • 1st site: Coast Live Oak Woodland • 2nd site: Oregon White Oak Woodland

• Designated two people to oaks (one counter and one recorder) as well as two people to Douglas Firs to survey the sapling and mature for each species at each woodland.

Results

Saplings (< 1 cm Mature (> 1 cm Type Locality DBH) DBH) Coast Live Oak Coast Live Oak Woodland 3 7 Coast Live Oak Coastal Douglas Fir Woodland 11 22 Oregon White Oak Oregon White Oak Woodland 3 14 Oregon White Oak Coastal Douglas Fir Woodland 1 12 Results

Coast Live Oak Locality: ● Douglas Fir: ○ Saplings: 26% ○ Mature: 51% ● Coast Live Oak: ○ Saplings: 7% ○ Mature: 16%

White Oregon Oak Locality: ● Douglas Fir: ○ Saplings: 3% ○ Mature: 40% ● White Oregon Oak: ○ Saplings: 10% ○ Mature: 47% Conclusion

● Our data suggests that Douglas Fir encroachment is present at the Fairfield Osborn Preserve.

● Our results can be used to understand the severity of Douglas fir encroachment.

● Our data can be utilized to manage the amount of Douglas Firs, allowing the management team to effectively remove the saplings. On our trip we removed 7 saplings as shown below. References

Barrett, T., Coleman, T., Frankel, S., Harrington, C., & Kelsey, R. (2010). The Mighty Oak Faces Challenges in the Pacific West. Science Update, (20), 5-7. doi:10.3897/bdj.4.e7720.figure2f Douglas Fir. (n.d.). Retrieved February 10, 2019, from https://www.nwf.org/Educational-Resources/Wildlife-Guide/-and-Fungi/Douglas-Fir Forest Inventory and Analysis Glossary. (2016). Retrieved February 13, 2019, from https://www.nrs.fs.fed.us/fia/data-tools/state-reports/glossary/default.asp Propagations by Sean. (2014). Retrieved February 7, 2019, from http://sites.psu.edu/plantpropagationsbysean/2014/11/23/how-to-grow-a-douglas-fir-from-/ University of California Agriculture and Natural Resources. (n.d.). Conifer Encroachment. Retrieved from https://ucanr.edu/sites/oak_range/Conifer_Encroachment/ University of California Agriculture and Natural Resources. (n.d.). Douglas-fir (Pseudotsuga menziesii). Retrieved February 7, 2019, from https://ucanr.edu/sites/forestry/California_forests/http___ucanrorg_sites_forestry_California_forests_Tree_Identification_ Douglas-fir/ University of California Agriculture and Natural Resources. (n.d.). California's Oak Woodland Species. Retrieved February 7, 2019, from https://ucanr.edu/sites/oak_range/Californias_Rangeland_Oak_Species/ University of California Agriculture and Natural Resources. (n.d.). Conifer Encroachment. Retrieved March 6, 2019, from https://ucanr.edu/sites/oak_range/Conifer_Encroachment/