Table 2. Species profile for the valley oak, Quercus lobata.
I. Name and plant group

  1. Family

  2. Scientific name

  3. Common name(s)

  4. Major cultivars

  • Fagaceae

  • Quercus lobata Nee

  • Valley/California white oak

  • none

II. General growth and development

  1. Growth habit

  2. Field i.d. features

  3. Native habitat

    1. range

    2. successional status

    3. plant associations

    4. soils

    5. seasonal precipitation

    6. hardiness

      1. min. temperature

      2. frost tolerance

      3. cold/chilling req’t.

  4. Life-span

    1. nature

    2. landscape

  5. Crown development

    1. height

    2. width

    3. general form

    4. number of stems

    5. epicormics?

    6. type branch attachm’t

    7. brittleness of wood

  6. Foliage character

    1. persistence

    2. form/shape

    3. simple/compound

    4. phyllotaxy/arrangement

    5. distribution

  7. Pattern of shoot elongation

    1. period of elongation

    2. relative elongation rate

    3. flushing pattern

    4. terminal bud

  8. Vascular system

    1. xylem character

    2. compartmentalization

    3. bark character

      1. thickness of bark

      2. overall texture

      3. odor

      4. strength

    4. susceptible to heartrot?

  9. Root system

    1. general character

    2. season of elongation

    3. depth

    4. forms buttress roots?

    5. forms root grafts

    6. relative windfirmness

    7. mycorrhizal associations

  • large, spreading tree location, leaf

  • valleys and foothills of CA below 2000 ft. climax riparian forests w/CA sycamore, poplar, willow; savannas w/annual grasses prefers deep, fertile alluvial loam 18in/yr, btwn. Nov. and May; dry summers; water table 3-12m. deep

  • USDA zone 7, 5°F tolerant

  • 300-500yrs. less

  • 50-80ft. 50-100tt.

  • rounded, spreading crown generally single trunk yes strong not very brittle

  • deciduous white oak group deeply lobed, white beneath simple alternate clustered at branch ends, especially as vigor declines

  • March-May moderate recurrent w/additional water determinate

  • ring-porous? moderate

  • thick rough, deeply fissured does not rip yes (Porla) rope-like roots extend beyond drip-line; forms strong tap-root as seedling presume late winter/early spring

  • 3ft. w/sinkers in capillary zone above water table

  • yes

  • yes

  • good

III. Reproductive development

  1. Primary mode of reproduction seed

  2. Age to first flower

  3. Bearing frequency

  4. Sexual reproduction

    1. season/timing

    2. structure

    3. terminal/lateral

    4. self/cross-pollinated

    5. mode of pollination

    6. flowers perfect?

    7. monecious/dioecious

  5. Fruit

    1. type

    2. mature

    3. objectionable?

    4. mode of seed dispersal

  6. Primary propagation method

  7. Other considerations

  • 15-25? 2-3 years btwn. crops

  • Feb.-May male-catkin; femalesolitary? lateral cross wind no monecious

  • acorn, 1.5-2in. long late Oct.-ea. Dec. no wind, squirrels, birds seed, but with relatively short viability period hybridizes freely w/other members of the CA white oak group (Lepídobalanus)

IV. Culture and management

  1. Relative tolerance

    1. soils

      1. pH range

      2. moisture

        1. overall moisture

        2. inundation

        3. seasonal concerns

    2. mineral nutrients

    3. alkaline soil

    4. heavy metals

    5. salt

    6. compaction

    7. atmosphere

  2. shade

  3. atmospheric contaminants

    1. ozone

    2. sulfur dioxide

  4. Response to disturbance

    1. mechanical

    2. biological

    3. release

  5. Transplant response

    1. relative ease

    2. season

    3. stock type

  6. Reaction to fire

    1. flammability

    2. response/recovery

  7. Pruning patterns

  8. Common insect problems

  9. Common disease problems

  10. Hazard potential

    1. pattern of failure

    2. summer branch drop?

    3. resp. to snow/ice loading not encountered

  • 6.0-7.5

  • best w/access to water table; drought tolerant once established good in winter, below foliage; young trees survive summer flooding below foliage dry surface (root crown) in summer occa. Zn and Fe symptoms moderate

  • poor poor well-aerated intolerant (moderate as seedling)

  • moderately sensitive; declines over several years due to construction injury established trees tolerate browsing seedling establishment curtailed by browsing, insect and rodent injury; regeneration good along drainage swales and road edges

  • poor, due to poorly branched root system fall containers only

  • moderate poor dead wood; concentrate on long, horizontal limbs w/poor taper, especially for trees w/history of summer branch drop oak pit scale twig and bud gall wasps oak moth Armillaria, Phytophthora, mistletoe, powdery mildew, twig and branch dieback (Diplodia, Cryptocline, Dothiorella)

  • sheds branches as crown thins; not prone to trunk failure yes

V. Values

  1. Wildlife value

    1. habitat

    2. forage

  2. Ornamental features

    1. bark

    2. flowers

    3. fruit

    4. fall color

    5. other

  • excellent acorns provide forage for small animals and birds

  • striking form largest American oak