PTIONS with herbicide larger saplings larger herbicide with O ACTORS seedlings and small saplings by hand or by saplings and small seedlings F Acacia melanoxylon Acacia EY Cut and treat Cut trees. and mature High seed production. 15–20 years. viable for Seeds reported stumps. cut and from roots from Can sprout Pull when the soil Wrench, preferably Weed with a is moist. REATMENT u K u u u T u funicles. oval, are seeds themselves The black, shiny,and long, a quarter-inch about can and ground. in the years viable for remain An indi- per year. 100,000 seeds can produce plant vidual be high particularly to appears Seed germination following fire. WEED WORKERS’ HANDBOOK WEED WORKERS’ (Acacia decurrens) (Acacia (Acacia melanoxylon) (Acacia Blackwood acacia is an evergreen tree that tree evergreen acacia is an Blackwood small acacia is a fast-growing wattle Green ESCRIPTION EPRODUCTION MPACT Legume or Pea Family (Fabaceae) Family Pea Legume or Blackwood acacia Blackwood Green wattle acacia ACACIA SPECIES ACACIA R well as seed from reproduces acacia Blackwood sprouting. and stump suckers root as by The roots spread vigorously. Seed production gener- of beginsally 2 and 4 years between age. Clusters of fragrant, pale yellow flowers resembling February. to small in January Brown, appear pompons seed pods,uptwisted long,develop 4 inches to in fall. in the and drop summer late pod Each holds red or pink pod the by to 6–10 seeds attached Blackwood acacia reportedly has an allelopathic acacia reportedly Blackwood effect, chemistry soil and inhibiting altering ofgermination plants.Likelegumi- many native plants,nous nitrogen-fixers, are acacias in nutrient-poor establish them to enabling soils. dense, form Acacias monotypic thickets of accumulation a thick and produce leaf litter. I Blackwood acacia and green wattle acacia are wattle green acacia and Blackwood and in disturbed areas typicallyboth found roadsides. Both grow well in moist soils but can tolerate drought. in height. 20–40 feet reaches has a single It trunk with rough, bark, gray a dense forms and bi- finely are pyramidal canopy. leaves Juvenile pinnatelycompound, but adult leaves are simple. They alternate,are narrow, straight to sickle-shaped, smooth, and leathery. The leaves a dull, and become long 4 inches to up measure green. dark to up thickets dense forms that tall shrub or tree tall.45 feet com- bipinnately are leaves The pound, flattened, green. and dark D

TREES 106 u Cut to 1 foot and cover stump with black INTERESTING FACTS plastic or fabric shadecloth. The genus Acacia is one of the largest in the u Cut to 1 foot and macerate stump. world, comprising around 1,000 species. u Girdle or Frill. Blackwood acacia is native to Tasmania, an island south of Australia, where marsupials eat u Drill and inject with herbicide. the seedlings. Heights of 130 feet have been recorded,while the oldest tree is 230 years old.It DISPOSAL Remove seed pods from the site when feasible. produces lumber of commercial value if grown The wood can be cut for firewood. on suitable sites. In some parts of the world, green wattle acacia is used in cosmetics for skin FOLLOW-UP conditioning, while the bark is used to tan Return to the site to check for seedling growth leather.Many Acacia species can be highly aller- and resprouts at least twice a year.Dig out or cut genic. and treat the resprouts.

Notes TREES

THE PLANTS: HOW TO REMOVE BAY AREA WEEDS 107