Tucson Mountain District, Saguaro National Park Vegetation Inventory, Mapping,andCharacterization Report,Saguaro National Park buckhorn cholla (Cylindropuntia acanthocarpa ) subcanopy (0.5–2m)ischaracterized by avariable succulents mixof that, from most to least frequent, include gigantea) isdocumented inall examples this of community, typically providing cover around of 1%. The with occasional dense inclusions where it outcompetes yellow paloverde patchy (0.66)associate that, when present, contributes cover 1–2%, of with some dense inclusions upto ironwood 10%.Desert (O. tesota ) isa a consistent (1.0),small (2–3m)tree with average cover around of 3%, show decreased cover and diversity. Yellow paloverde and vegetation cover ishigher on slopes, while examples on bajadas and aspect within this association. In general, species diversity isgreater triangle burragweed (Ambrosia deltoidea). There are trends inlandform neya tesota), with anunderstory dominated by asuite succulents of and yellowof paloverde (Parkinsonia microphylla ) and desert ironwood (Ol- This shrubland ischaracterized by anopen(<10%cover) canopy (>2m) Saguaro /Yellow paloverde(Desertironwood)/Triangle burragweedShrublandAssociation(P) Shrubland Association(P) 19. extrusive, and intrusive igneous rock. materials are most commonly new and amixof old alluvium, and on slopes, also include mixed colluvium, lower to upperalluvial fans and lower toeslopes hills, but of isoccasionally located on mountain slopes. Parent southern areas the of park from 683to 1,042meters (2,240–3,420ft). This community isgenerally found on luvial landforms that predominate inthe western the of half TMD, but are found inthe northern, eastern, and This community covers the 27%(2,728ha/6,741 ac)of Tucson Mountain District (TMD). It isrestricted to al- roughly the 20%of total cover. dense inclusions upto 12%. This species often has the greatest cover all species of present and accounts for stratum isdominated by triangle burragweed (A. deltoidea), ( Opuntia engelmannii).Combined, these species contribute around 10%cover to the community. The field Carnegiea gigantea/ Parkinsoniamicrophylla( , chain-fruit cholla (Cylindropuntia fulgida ) ( P. microphylla ) is typically with cover 3–8%,including of some Olneya tesota) ( P. microphylla). Saguaro (Carnegiea • • • • • Common species
/ Opuntia engelmannii Ambrosia deltoidea Olneya tesota Parkinsonia microphylla Carnegiea gigantea Ambrosiadeltoidea , and cactus apple
Tucson Mountain District, Saguaro National Park