My previous two columns set forth some of the benefits oak woodlands bestow on our environment and us. I was preparing for my presentation on March 12 at the forum on Measure C, the Napa County Watershed and Oak Woodlands Protection Initiative.
As luck would have it, the computer froze up and my PowerPoint presentation stopped cold. Fortunately I had backup: Hand-written 3 by 5 cards. I was able to soldier on.
Time was short, and with the technical breakdown I was not able to cover everything. I am taking this opportunity to fill in some gaps. Here are some main points:
My topics included oak woodland benefits to watersheds, native oaks resistance to fire, threats to oak woodlands, some concerns being expressed about the initiative, and a few closing thoughts.
Benefits of forests and woodlands
These are documented and codified across the country in ordinances and public policies.
The city of Calistoga tree ordinance protects all valley oaks, including small seedlings.
The city of Napa has a moderate tree ordinance. For example, it protects coast live oaks of 12-inch trunk diameter and larger on any commercial property and on private property one acre and larger. Those protections do not extend beyond the city limits.
Sound trees enhance property value. As a consulting arborist, I have occasion to appraise tree values. Applying the appraisal method to some example trees I found this:
— A 5-inch trunk diameter coast live oak, the smallest size protected under Measure C, can be appraised up to about $890.00, depending on its condition and location. If you buy such a tree in a 48-inch box and have it planted, expect to pay about $1,900.
— A 12-inch diameter coast live oak, the smallest size protected under the Napa tree ordinance, can be valued up to about $4,000.
— A 40-inch diameter coast live oak recently yielded an appraised value of $47,000.
Erosion control benefits the farmer
“Slow it, spread it, sink it!” is a motto about good rainwater management. That is exactly what trees do. Leaves slow and spread raindrops. Leaves, twigs, branches and trunks hold and slowly release rainwater. The improved soil under oak canopies allows rainwater to soak in, rather than run off, and the trees allow for ground water recharging.
The benefits of soil conservation extend to the farmer. Whereas cutting down trees right down the stream banks invites the loss of the very soil needed for farming, saving the trees in buffer zones provides stability for sustainable farming.
Air quality: In addition to several air quality benefits mentioned in previous columns, trees and all green plants generate oxygen.
Fire: I have been examining hundreds of trees after the October wildfires. I have noticed many thin-barked, and non-native trees, such as English walnuts and Japanese maples are susceptible to heat damage. Their cambial zones are easily killed.
In contrast, coast redwoods and coast live oaks, especially the larger specimens, are very resistant. Last fall, just a couple months after the fires, many began to sprout new growth from latent buds on the branches, trunks and root collars.
The effects were mixed, depending on heat intensity. Many trees were killed, but those that survived went right back to work. These species have been living with fire for a long time.
On that note — time — I found documentation from the fossil record, oaks resembling California native oaks existed about 20 million years ago.
Forests expanded and shrank with changes in climate. In the Pliocene Epoch, 3 million to 4 million years ago, coast live oak woodlands were well established in areas now known as Napa and Sonoma. At that time, the Central Valley was an inland sea, and Homo sapiens had not yet emerged as a species.
Considering their long-term stability, the many benefits they provide us for free, and the way they frame the world famous views beloved by local citizens and visitors, do they deserve special protection?