Faced with extreme drought conditions, many trees shown signs of drought-related stress. Stress may not kill a tree directly, but it can weaken it – making it susceptible to more serious secondary pathogens like pest infestations and fungus. A healthy tree can fight an infection, but a thirsty one may not and it’s because of this, that tens of thousands of trees have died throughout San Diego County.

In an effort to preserve trees, the Department of Parks and Recreation (DPR) developed a Heritage Tree Preservation Program. This program analyzes the health of trees on County land, and establishes requirements for maintaining diversity and density to safeguard their existence and the growth of new natural landmarks, for generations to come.

Key components of the program are to:

• Evaluate the health of existing trees within our parks using infrared analysis and methodologies commonly used by land managers.
• Ensure no net loss of trees within our parks. Trees affected by drought-related or pest threats are removed and replaced at a ratio of 3:1. Additionally, when a tree is lost, its spirit lives on; trimmed trees can be mulched to place on trails, segmented and cut for firewood – even milled to create park benches.
• Diversify tree species by making sustainable tree selections that represent various families of native tree species (that are also low maintenance and flourish with reduced watering regimens).

When new trees are planted, we follow a couple of general rules:

• Large trees should be local, native, and grown in a box (up to 48 square inches).
• Large trees should be planted in areas where they are interspersed with small trees to permit a better tap root system.
• All trees should be free of disease and show no signs of stress or pest infestation.
• All trees should be planted with pre-approved deep root drip irrigation systems.

Mature trees offer shade and contribute to biodiversity. They also serve as important climate buffers to moderate temperature and moisture. DPR is building sustainable landscapes within parks to support local ecosystems, enhance park experiences, and reduce our carbon footprint.