Exclosure size affects young blue oak seedling growth
Blue oak, a tree native only to California, is notoriously slow-growing, and its low regeneration rate has prompted concern about the species’ future survival in some areas of the state. We studied the use of fencing (exclosures) to protect seedlings from herbivores and promote faster growth. Placing exclosures 2 and 4 feet in diameter around blue oak seedlings increased their height and canopy area when compared to a control without exclosures. The 4-foot exclosures increased growth (height and canopy area) compared to the 2-foot exclosures. It appeared that exclosures reduced damage from both wild and domestic herbivores, resulting in accelerated growth rates.