Weed control improves survival of transplanted blue oak

Weed competition is recognized as a factor affecting survival of California blue oak seedlings in artificial plantings. Three alternative weed-control strategies were examined in a series of annual plantings at two locations using 2- to 3-month-old nursery stock. The effects of herbicides, porous plastic mulch mats and impervious plastic mats were compared. No one strategy was superior, but all resulted in greater seedling survival than with no weed control, and generally also resulted in taller blue oaks. Use of herbicides was the least-expensive weed-control method. Much of the seedling mortality was attributed to depredation by rodents.