By Diane C. Kennedy.
Western Sycamore, Platanus racemosa. https://calscape.org/Platanus-racemosa-(Western-Sycamore)
The West is coming out of a hundred years of unnaturally high rainfall. Many of the thirsty trees that were planted and flourished during that time are failing. Pines, liquidambars, birch… so many that need humidity, a high water table and cool air are dying, leaving a big gap in the treescape. Also, with smaller properties and the fear of fire, smaller trees are desired by homeowners.
With the decrease in the treescape we have less to buffer the wind, and the wind is stronger and drier because of it. Wind slows and humidifies as it passes through leaves.
Unfortunately, many pest trees such as eucalyptus, Brazilian and California (from Peru) pepper are surviving and even being planted by the dozens along driveways and property lines. These trees steal water from great distances around them and produce a substance that makes them allelopathic: they retard or kill any nearby competing growth. Besides being extreme fire hazards, Eucalyptus also ‘self-prune’ in hot weather, dropping very heavy branches on whomever is underneath. If you have trouble with fruit trees, ornamentals, vegetables… anything, look to see if there is a eucalyptus or pepper in the vicinity.
We need to replant our treescape with natives.
Native plants offer the best habitat for our native birds and pollinators. Most natives use very little water once established, and therefore do not send out thick roots to steal water and lift pavement. Live Oak trees are keystone plants and offer habitat to over three hundred species. Sycamores turn lovely colors in the fall and take up thousands of gallons of water to both store and to release, humidifying the air. Hummingbirds scrape the fuzz off the underside of sycamore leaves to use in their nests. Palo Verde, Western Redbud, Desert Willow, Chilopsis, Desert Olive, Manzanita, Coast Tasselbush: these are all very drought-tolerant lovely trees that require very low water once established. Tall shrubs such as Toyon, Coffeeberry, Redberry, Lemonade Berry and Sugarbush can be used as privacy hedges or specimen plants, and the birds will love you for it. Plus, there are so many more to choose from.
California Live Oak, Quercus agrifolia, https://calscape.org/loc-California/live%20oak(%20)?newsearch=1
Keeping a landscape hydrated is key for fire protection, and you can have well-hydrated native plants using far less water than you would with non-native ornamentals.
Insist on native trees being planted in common areas, on streets and in your own yard. If you have the room, plant trees, and help fight desertification.