BOTANICAL AND ECOLOGICAL CHARACTERISTICS
SPECIES: Pinus quadrifolia | Parry Pinyon 



GENERAL BOTANICAL CHARACTERISTICS : 
Parry pinyon is a long-lived, slow-growing, native tree that grows from
16.5 to 33 feet (5-10 m) tall [26].  According to Keeley [12], pinyons
often live 200 to 500 years.  The branches of Parry pinyon are stiff,
low, and spreading, giving younger trees the appearance of a pyramid.
Older trees develop a more rounded, irregular crown.  The bark is thin
and smooth on young trees, becoming deeply furrowed and scaly with age.
Needles usually occur in bundles of four, but bundles of three and
sometimes five are found on the same tree [22,26].  Conelets are borne
singly or in clusters of two to four.  Cones are 1.2 to 2 inches (3-5
cm) long, with thick cone scales [26].  

Growth of pinyons is dependent upon soil moisture stored from winter
snows.  Pinyons have vertical taproots as well as lateral roots; both are
capable of active absorption.  In shallow soils, lateral root systems
extend well beyond the radius of the crown [36].
 


RAUNKIAER LIFE FORM : 
   Phanerophyte


REGENERATION PROCESSES : 
Minimum seed-bearing age for Parry pinyon is 10 to 20 years of age.
Optimum seed production occurs after 50 years of age.  Good seed crops
are produced every 1 to 5 years [12,13].  Cones produce relatively few,
large, wingless, edible seeds that are well-adapted to dispersal by
birds, rodents and other mammals [17,20].  Birds can disperse pinyon
seeds 12 miles (20 km) or more [12].  Birds and rodents cache pinyon
seeds in the ground, often at depths favorable for germination [20].
Fresh pinyon seeds have high viability and germinate readily with little
or no stratification.  They lose viability rapidly after 1 year.  Seeds
usually germinate in the spring if soil moisture is sufficient.
Seedlings need some shade to survive [12,20].   

Although the pinyon pines are tolerant of temperature and moisture
stress, water is the most limiting factor in seedling establishment and
growth [12,20].  

Parry pinyon does not reproduce vegetatively [12].    


SITE CHARACTERISTICS : 
Parry pinyon occurs on rocky slopes with thin soils that are typically
well-drained [5,20].  Parry pinyon grows at elevations of 3,960 to 8,250
feet (1,200-2,500 m) throughout its range and is rarely found at
elevations over 8,910 feet (2,700 m) [21,26].  


SUCCESSIONAL STATUS : 
Obligate Climax Species

The pinyon pines are shade-intolerant as adults but require some shelter
from shrubs or tree crowns to establish [20,35].  Pinyons can invade
surrounding grassland communities [25,35].


SEASONAL DEVELOPMENT : 
Parry pinyon flowers in June. Cones ripen in September and seed
dispersal begins in September and October [13].
 

Related categories for Species: Pinus quadrifolia | Parry Pinyon