Oak trees are very sensitive to environmental changes such as; changing of original grade within the dripline of the tree; over watering, particularly in the summer months, and; over pruning.

For the most part oak trees require little or no pruning other than periodic deadwooding. In fact, the pruning of green tissue increases the probability of disease organisms gaining entrance into a tree. Pruning of oak trees should be limited to the removal of dead or diseased limbs in fall and winter months with no heavy pruning at any time. Occasionally a mature tree may benefit from a light thinning (removal of 10 to 20 percent of live green foliage) to reduce the weight of branches and to open foliage for light penetration and reduced wind resistance. Also, pruning may be required to provide vehicular and pedestrian clearance, and/or to provide clearance from buildings and other infrastructure such as traffic control devices, streetlights and energized lines.

Oak trees should never be severely pruned. Severely pruned trees are unsightly and respond with vigorous, weakly attached , watersprout growth that is susceptible to powder mildew. Large pruning wounds are also more subject to decay . To prevent the spread of disease, climbing “gaffs” shall not be used at any time when pruning oak trees.

All oak tree pruning shall comply with the International Society of Arboriculture “Tree Pruning Guidelines”; The American National Standards Institute, “ Trees, Shrubs and Other Woody Plants Maintenance Standard Practices” (ANSI A300 ); and the City of Los Angeles “Tree Trimming Standards” to ensure proper pruning practices.

With your cooperation and understanding we can continue to protect the legacy of Los Angeles ' native oak tree forest.

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