Recently, a homeowner called SRT with questions about pruning an oak tree on her property. She explained that a neighbor had cut limbs that were above his property, and she wondered if she should cut some on her side to balance it. After recommending that she call a licensed, insured arborist for more information, we told her that when limbs are removed, an imbalance is indeed created. Then she asked what SRT does at Kaweah Oaks Preserve when a tree “needs a trim.”
SRT does not trim trees on its nature preserves, with the one exception: when a tree falls into one of the waterways on the preserve. In the last year, the Kaweah Delta Water District removed two large oaks from the waterways at Kaweah Oaks Preserve. This ensures that water can continue to flow to farms, but just as importantly, it keeps bridges over the waterways safe.
When oaks fall in areas away from the rivers, SRT leaves them there because fallen trees provide important habitat for wildlife. For years to come, a fallen oak will be a food source for insects, which will in turn feed birds. It also makes a nice roof for burrowing mammals, feeds vining plants such as the native blackberry, provides habitat for birds and other small creatures, and will eventually feed the other oaks that will enjoy the open sky available to them.
In 2008, a survey of the preserve found the oldest trees were roughly 130 years old, with an average height of 85-95 feet. One measurement counted the number of seedlings per acre with some areas having more than 100 seedlings per acre. Clearly, the trees are living up to their reputation as a vigorous tree when given the chance to grow.
Most people in the San Joaquin Valley know how vigorous oak seedlings are. At Kaweah Oaks Preserve, there is clear evidence that the many age classes of oaks are present. While it can seem sad to lose a majestic old oak that has been alive since the 1880s or perhaps earlier, we should remember that the valley oak as a species has been thriving here for much longer, and will continue if we work together to be good land stewards.