Quercus cedrosensis

In southern California, as well as northern parts of Baja California (Las Californias Region), this species is threatened by habitat loss due to land use changes. These changes include road construction and Border Patrol activities as well as urban and rural development (CNPS 2001). Southern California occurrences are 0.5–1.5 m from the Mexican border, making these localities very sensitive to "security" issues. This area is closely surveilled by U.S. authorities for illegal immigration issues and a triple fence was erected, destroying part of the vegetation of this region. Traffic control infrastructure was more recently implemented further implicating the survival of other specimens of this shrub oak. From 2004–2014 in the Las Californias region alone, about 435 km² area has been attributed to direct habitat loss; half of that lost compromises rare communities. Effects of these losses include habitat fragmentation, unnatural fire regimes, clearing/logging, and habitat type conversions (Stallcup 2015).
On Cedros Island, the high number of introduced mammals, such as goats and dogs, have decreased the native flora and vegetation, although not as severely as on the other large Pacific Islands. This difference could in part be due to evolution in the presence of native herbivores which are absent from the other islands. Credos Island has also experienced deforestation of the southern canyons (Mellink 1993). 
A more alarming threat this species faces, pertaining to its mainland occurrences throughout Baja California into the southern most extent of this species range, is one in which further desiccation could eliminate the mainland subpopulations of Q. cedrosensis, leaving only the insular subpopulation as a relictual endemic. There is an additional concern that mainland populations are facing threats of introgression as leaf morphology begins to shift as well (Muller 1965).

This species is known to exist in only three ex situ conservation sites around the world (BGCI 2015). Quercus cedrosensis' northernmost range rests within the Las Californias region, where more than 400 rare or endemic species exists. Thus, conservation initiatives are also being prioritized in this region that would require land uses and management to maintain habitat integrity and allow natural ecological processes to continue (Stallcup 2105). The species is also located within three protected areas in Mexico: Parque Nacional Sierra de San Pedro Martir, Area Natural Protegia Valle de Ios Cirios, and Reserva de la Biosfera El Vizcaino. There is no current management or planning for Q. cedrosensis in these locations, and the type of land use allowed within these natural areas is not known. Limited protection is likely provided, but could perhaps be built upon more easily in the future, compared to completely unprotected areas (White et al. 2006).