Posts Tagged: Laurence Costello
The oak is a common symbol of strength and endurance, but some of the majestic trees in California are buckling under the pressure of urbanization, reported the Sacramento Bee this week.
In most cases where urban environments are shaded by oaks, the trees towered over the landscape long before humans moved in. Costello said witnessing the heartbreaking decline of urban oak trees was a catalyst for writing the book.
"It's just a shame; they're such a beautiful tree and the symbol species of California," Costello was quoted in the story.
Costello provided reporter Debbie Arrington with basic tips for protecting oaks in urban environments:
- Know what kind of species you have. "Is it a California native or imported? It makes a huge difference."
- Don't surround a valley oak with lawn; irrigation three times a week can cause fungus problems in the root and crown.
- Know where the oak roots are before installing a swimming pool or an irrigation line. Oak roots are very sensitive.
- Use a layer of mulch – preferably bark – to keep oak roots comfortable.
- Fertilizer is usually unnecessary and pruning can weaken trees.
Oak trees may seem needy, but Costello says they are worth the extra effort. California's oaks are difficult to regenerate and it can take centuries for trees to develop the massive canopies and enormous trucks found on the most highly valued oaks.
Although shade-tolerant turf can be used under oaks, it is best to replace the turf with mulch.