The best prevention is to be sure your trees are healthy and happy
Woodpeckers are part of the Picidae family that also includes piculets, wrynecks, flickers, and sapsuckers. They are found in most of the world except for Australia, New Zealand, Madagascar, and extreme polar regions. We have 17 species here in California.
They can range in length from just under 3 inches to nearly 20 inches and can be fairly drab in color (olive and brown) to vividly bold (bright red, black, white and gold). They have short, strong legs, and most species have four toes, two of which face backward, making it exceedingly easy to climb and grasp onto tree trunks and limbs.
Although it may seem that a persistent woodpecker is killing your tree, the opposite is generally true. Woodpeckers actually feed on insects that have invaded the bark of an already distressed tree.
Woodpeckers are attracted to wood-boring beetles, termites, carpenter ants, caterpillars, and spiders. However, they will also eat nuts, fruit, bird eggs, lizards and small rodents.
They prefer wood that is already dead for their foraging and nest building. Since most trees have some amount of dead wood, these birds are usually not considered harmful. When they detect insects within decaying wood, they use their strong beaks to make small holes and then extract the prey using their extremely long, barbed tongues.
Sapsuckers, as the name implies, prefer to feast on tree sap and the insects that are attracted to tree sap. These birds are known to voraciously attack trees, causing serious damage and sometimes death to the tree. They are migratory birds and can wreak havoc on entire groves of trees throughout the United States. According to the U.S. Forest Service, sapsuckers cause mortality rates in 67 percent of gray birch, 51 percent of paper birch, 40 percent of red maples, 3 percent of red spruce, and 1 percent of the hemlock that they attack.
They frequently return to the same trees year after year. They increase the size of their holes, looking for more sap and inflicting more and more damage. As the tree declines, bacteria and fungus can take hold, amplifying the damage and increasing the likelihood of tree mortality.
Sapsuckers usually make tiny holes in a horizontal pattern around the tree, while woodpeckers mostly make large, random holes. Most damage is caused during their breeding season that runs from February to June.
All woodpeckers are protected under the Migratory Bird Treaty Act of 1918, and some are listed as endangered species.
So what can you do to protect your trees?
Wrap burlap or hardware cloth around the areas of the tree that have been attacked. There are also repellents such as Tanglefoot Bird Repellent that will help fend off the noisemakers. However, when deterred, they will usually seek out another tree. If they are attacking an already sick tree, one you are not particularly fond of or one that is not in the best location, it may be best to just let them peck in peace!
The best preventative measure is to regularly inspect your trees for signs of infestation. Termites and carpenter ants love to feast on wood, and trees are a good source. So, if you see an invading pest, deal with it right away.
First and foremost, determine what type of pest you have and then use an eco-friendly, organic method of control. When using any pesticide, (organic or conventional) it is important to determine exactly which type of pest you are trying to kill and use only the recommended dose. More is definitely NOT more, and if you aren't careful, you can wipe out an entire ecosystem of beneficial insects and species.
by UC Master Gardener Rebecca Jepsen
This article first appeared in the February 17, 2019 print issue of the San Jose Mercury News.
Knowing soil types and water requirements may help us grow healthy vegetable gardens and flowers, but it is also vital when it comes to trees.
Igor Lacan, environmental horticulture adviser for UC Cooperative Extension, says as we move toward warmer temperatures with less predictable annual rainfall, we will need to make smart choices about our landscapes.
“Even in a drought, it is essential to prioritize your trees,” Lacan says. “Trees not only support our native birds, bees and wildlife, they provide major ecosystem services to us as well. Urban trees lower the ambient temperature, thereby reducing the need for air conditioning, sequester carbon from the atmosphere, provide stormwater capture, decrease pollution and enhance the property value and aesthetics of your home.”
Start with soil
In order to practice responsible irrigation — using enough water to keep a plant alive and no more — knowing your soil type really does matter.
Soil type, or texture, refers to the proportions of sand, silt and clay particles in its makeup. Sandy soils are coarse and drain quickly. Plants in sandy soil need frequent watering and may need fertilizer.
Clay particles are very fine and become glued together when wet, and although clay soil can be slow to drain, it retains moisture and minerals, requiring little to no fertilizers.
The roots of newly planted plants may have a harder time getting started if the soil is hard and dense, but once established, plants tend to thrive in clay soils.
Silty soil is found along our riverbeds, lakes and other riparian areas. Particles are smaller than sand but not as fine as clay. It drains well and has good nutrient retention.
Loam represents a combination of sand, silt and clay and most of the Bay Area has clay or loam soil.
To tell what kind of soil you have, moisten a handful of it and give it a firm squeeze. If it holds its shape but crumbles when you give it a poke, you have loam. If it holds its shape without crumbling, you have clay. If it falls apart as soon as you open your hand, you have sandy soil.
Knowing your soil type will guide you in how much water to apply and how often.
To gage soil moisture levels, you will need to dig down to the root level. For trees, use a shovel or an auger to get 12-18 inches below the surface. After watering to this depth, soil should be moist but not drenched.
For mature trees, deep water infrequently, about once a month. Imagine refilling a 12- to 18-inch deep water reservoir around the tree's roots.
It's important to water beneath the entire canopy. Installing a Tree Ring Irrigation Contraption (TRIC) is a great way to accomplish this.
Newly planted trees may need only 10-15 gallons per week, but they may need additional water in extremely hot weather.
In all cases, a good rule of thumb is to water deeply and observe your tree. If the tips of the leaves and branches start to droop, it's time to water again.
You will then be able to properly set up your automated irrigations systems. But remember, they need to be changed seasonally as the weather and temperature fluctuate. Online watering calculators can also be helpful.