PLSC 381 Module 5 & Plant List 7

considerations in tree selction

• native plant community (higher chance of success)

• water/light needs

• low temperature tolerance/heat tolerance

• soil preference

• deciduous vs evergreen

• flowers

conifer

a tree that bears cones, has needle-like or scale-like leaves that are typically evergreen

hardwood (angiosperm)

a tree that has broad leaves and reproduces with flowers, enclosing its seed in a fruit or nut

monocot tree

a flowering angiosperm that only has one seed leaf (cotyledon), parallel veins, and cannot grow wood or outwardly expand its stem

what is height and width to be considered a tree?

grows at least 20’ at maturity, has a central trunk greater than 6” at chest height

how many native species of oaks are there and how many grow into trees?

21 native species, 10 grow into trees

at what elevation do oaks grow?

sea level to 9000 feet

Sudden Oak Death overview

Phytophthora ramorum is the fungus responsible for SOD

10,000s trees killed

no cure

carrier host vs terminal host

species will die if they are a terminal host

symptoms of SOD

• thick reddish or brown to black sap oozes from cracks in trunks

• leaves yellow then turn brown

• often attacked by wood-boring beetles

• secondary opportunistic fungus

what oaks are resistant to SOD?

Quercus lobata, Quercus douglasii, Quercus garryana

SOD host-carriers

Umbellularia californica, Heteromeles arbutifolia, Aesculus californica, Acer macrophyllum, Vaccinium ovatum, Frangula californica

oak wilt

a lethal disease caused by fungus Bretziella fagacearum

invades and plugs the tree’s xylem, affects all oak species

how to prune oaks

• prune in fall or winter for evergreen species, winter for deciduous species

• avoid heavy pruning (remove max 15% of canopy)

• do not change the grade/soil level

• keep ground cover with leaf litter mulch