California Drought Kills 27 Million More Trees 

Another 27 million trees died in California last year due to the lingering effects of drought, according to new aerial survey data from the U.S. Forest Service. That brings the total number of trees killed statewide to a staggering 129 million since 2010.

trees killed by drought

In a typical year, about one million trees die across California. But beginning in 2014, that number began ticking up as aerial surveyors with the U.S. Forest Service started to notice entire hillsides turning yellow, brown and orange. At the height of the drought, in 2016, they counted 62 million dead trees in a single year (here is a map of the mortality progression).

Adrian Das, a forest ecologist with the U.S. Geological Survey, previously told KPCC that he wasn’t surprised that after a single wet winter, trees were still dying.

“The trees have been weakened and under a lot of stress and we have these beetle populations that are doing well,” he said.

Drought often kills trees indirectly. By depriving them of water, trees become weakened and unable to ward off diseases, fungus or bark beetles, which are always present in the forest but explode in numbers when trees are unable to fight them off.

Last winter, more rain and snow fell on parts of the Sierra Nevada than in the previous four years combined. Some trees have recovered, and the death rate is slowing down.

The lower rate could also be a result that so many trees have already died, so there’s just not much left to be killed, said Stephanie Gomes with the U.S. Forest Service’s tree mortality task force.

Indeed, this year’s data shows species with lower death rates in the past are dying in different parts of the state. Previously, the hardest-hit species and regions of California were pines at lower elevations in the Southern Sierra Nevada, where the highest temperatures sucked water out of soil, depriving trees of what little moisture existed. Now, Gomes said death rates are increasingly in higher elevations among fir trees in northern reaches of the mountains.

Part of the problem, scientists say, is that forests throughout the West have too many trees. Historically, many forests used to experience fire more frequently than they do now, which resulted in saplings and small trees dying in the blazes and leaving many forests more open. In the past century, firefighters put out those fires, meaning more small trees were able to survive and forests became crowded.

Now, climate change is forcing more trees to compete for a dwindling amount of water. As temperatures rise due to increasing greenhouse gas emissions,more water gets sucked back into the sky and out of the soil and the ground.

Gomes said the U.S. Forest Service is trying to compensate by thinning out forests either through logging or with prescribed fires so trees don’t have as much competition for water. The agency will also be prioritizing removing dead trees that may pose a safety risk, such as those growing along highways, campgrounds, and power lines. But it is difficult for the agency to do this work when more than half its budget every year goes to fighting wildfires.

“As fire suppression costs continue to grow as a percentage of the Forest Service’s budget, funding is shrinking for non-fire programs that protect watersheds and restore forests, making them more resilient to wildfire and drought,” Randy Moore, Regional Forester of the U.S. Forest Service, Pacific Southwest Region, wrote in the news release.

Source: California Drought Kills 27 Million More Trees | KQED Science

Tree trimmer dies in accident at Stanford housing complex

Sad industry news:

The California Division of Occupational Safety and Health is investigating the work-related accident that turned fatal, Cal/OSHA spokesman Luke Brown said. Romero was employed by Arborwell Inc., a tree trimming and maintenance company based out of Hayward.Cal/OSHA investigators were on scene Saturday looking into the circumstances surrounding the accident. The investigation is expected to take about six months to determine if there were any workplace safety code violations, Brown said.A search of online

Source: Tree trimmer dies in accident at Stanford housing complex | News | Palo Alto Online |

The Most Popular Trees for Commercial Buildings in Each Region Are…

Best Landscape Trees

Landscape design for commercial sites can offer unique challenges as not only does everything have to look good, there are special considerations such as exposures, vehicle traffic and the public’s use of the site that must be taken into account. Tree maintenance for many commercial locations can necessitate particular consideration as trees must often be irrigated, pruned, and cared for in areas of high public traffic and in many cases, in parking lots which adds a whole new dimension of complexity. There are some trees, however, that are strong winners in commercial establishments. The list below will get you started in your thinking.

Shade Trees for Temperate Parts of the U.S.

Pistache (Pistacia chinensis) Slow to moderate growth from 30-60 feet tall with nearly equal spread. Good fall color, foliage turns luminous orange to red (sometimes shades of yellow). This is the only tree to scarlet in the desert. Tolerates a wide range of conditions and is drought tolerant when mature. Reliable tree for street side or parking lot planting. Zones 4-23. Little grown in 4-7.

Pin oak (Quercus palustris) Moderate to fairly rapid growth to 50-80 feet tall, 30-40 feet wide. Wait to remove lower limbs until tree is mature and has formed an open, rounded top. In brisk fall weather, leaves turn yellow, red, and finally russet brown. Less tolerant of dry conditions than most oaks. It is a fine tree for growing in grass. Zones 2-10, 14-24.

Hackberry (Celtis sinensis) Moderate growth to 40 feet tall and nearly as wide. Rounded crown and spreading, sometimes pendulous branches. Leaves to 4 in. long, smoother and glossier than other hackberries. Resistant to oak root fungus. Good street, turf or parking lot tree, as it is deep rooted. Drought tolerant. Zones 8-16, 18-20.

Evergreen Trees for Temperate Parts of the U.S.

Norway Spruce (Picea abies) Fast growth to 100 feet tall, 20 feet wide. Tolerates heat and humidity better than most spruces. Extremely hardy and wind resistant. Valued for windbreaks in many areas. Zones A2,A3; 1-6, 14-17.

Southern Live Oak ( Quercus virginiana) Moderate to fast growth, eventually reaching 40-80 feet tall with a heavy limbed crown spreading twice as wide. Long lived. Best in deep, rich, moist soil. Best oak for lawn planting is low desert. In hot interior climates, it’s the most attractive of all evergreen oaks. Zones 4-24.

Arborvitae (Thuja ‘Green Giant’) Partial shade in hottest climates. Can grow 3-5 feet per year, ultimately reaching 30-50 feet tall, 10-20 feet wide. Although arborvitaes will take both damp and fairly dry soils, they grow best in well drained soil. Shear as a tall hedge or use as a tall screen. Zones A3; 1-9, 14-24.

Commercial Trees for the Southwest Desert & Arid Regions

Palo Verde trees (Parkinsonia aculeate), also (Cercidium floridum) Tough, trouble free desert tree valued for floral display, shade and colorful bark. These trees attract birds. Prune only to enhance form. Lightly filtered shade is cast by intricate canopy of twigs rather than by tiny leaves. Zones 8-14, 18-20.

Mesquite trees (Prosopis spp.) They are among the toughest and most useful of desert trees. They have roots that will travel great distances to find water, however they can also adapt to lawn water. With adequate water can grow to 30 feet with a picturesque, spreading canopy approximately as wide. Little pruning is needed; do the job only to remove broken or dead limbs. Zones 10-13, 18-24.

Palm Trees for Commercial Sites

Fan Palms (Washingtonia spp.). Are best suited to large properties, avenues, parkways. Mexican fan palm (Washingtonia robusta) to 100 feet tall, 10 feet wide; trunk is slightly curved or bent. Head of bright green foliage is more compact; leafstalks are shorter, with a red streak on the undersides. Zones 8-24; H1, H2.

Date Palms (Phoenix canariensis) Big, heavy trunked plant to 60 feet tall, with a great many bright green arching fronds that form a crown to 50 feet. Need regular water. Best planted in parks, along wide streets, or in other large spaces; not for small city lots. Zones 8,9, 12-24; H1, H2.

Trees are an essential component of your property’s landscape and often times can require quite an investment. Make sure you are setting yourself up for success with trees capable of withstanding not only your climate, but also the particular nuances offered by your site. While the zone recommendations provided here are guides, there are considerations about the conditions in your specific area that should be taken into account so consultation with an experienced landscape professional is encouraged.

Source: The Most Popular Trees for Commercial Buildings in Each Region Are…

Healthy Habits – A little prevention goes a long way for Cleary Bros.

Todd Kirchner is an arborist for Cleary Bros., a 220-employee California company with landscape maintenance, construction, and tree care divisions. He diagnoses disease and pest issues for the trees in his care and prescribes treatment. Sometimes he recommends a change in cultural practices, like watering, mulching or root protection. Sometimes he just recommends letting nature do its work. But sometimes a tree needs more help getting healthy.

pear-tree-fire-blight pear-tree-treated-results

Pear tree with a severe fire blight infection (photo taken June 2015). The tree was pruned summer of 2015.

The tree was then treated with Arbor-OTC early spring of 2016 with good results (photo taken April 2016).


In those cases, Kirchner has a suite of products ready to go. NutriRoot, Arbor-OTC, IMA-jet 10, PHOSPHO-jet are all trusted pieces of his toolkit.

Arbor-OTC is a micro-injectable systemic antibiotic for the treatment of bacterial infections of trees and palms. Kirchner uses it primarily for fireblight control in pear trees. He says it’s best used preventatively rather than therapeutically. He will treat trees in the springtime and prune whatever is already damaged in the summer to remove the damage.

Kirchner uses IMA-Jet 10 to control sucking insects. He prefers it because he’s seen no sign of breakthrough — when the product’s active ingredient begins to drop in effectiveness, leading to an insect resurgence. IMA-jet 10 stays at a consistent level throughout the entire growing season.

“It has very good staying power,” Kirchner says.

NutriRoot has been a key component of Kirchner’s summertime watering program. Drought-stressed trees receive supplemental water, and NutriRoot’s surfactant been particularly important to thirsty trees in less-than-ideal soil.

“In the bay area, you have high clay compacted soil — it’s like concrete,” Kirchner says. “Nothing is getting in. With the soil surfactant, it’s able to break into the soil, allow water to penetrate and hold in the soil for longer. We saw really good results with that last summer, conservatively we kept about 300 trees alive through last year using that product on all our projects.”

PHOSPHO-Jet is Kirchner’s preferred fungicide for leaf and twig and stem diseases like sycamore anthracnose or pear black leaf spot. Even with an effective product, it’s necessary to set up a protection plan.

“You have to have the end game in mind before the project even starts,” Kirchner says. “You have to know what you want to accomplish or what needs to happen before you even begin to write a proposal or specify a treatment program.”

For instance, preemptive PHOSPHO-Jet treatment for leaf spot in the fall can prevent a lot of remedial work in the spring. Kirchner is always looking ahead. If you know a certain time of year tends to have perfect weather conditions for a fungus to develop, don’t wait. Get those trees in that affected area protected ahead of time.

“If you can save yourself from having to be a firefighter, you can put out problems before they become problems and make the client happier,” Kirchner says. “You look better and the trees look better which adds value to the property.”

Over the years, Kirchner has developed solid relationships with the people at Arborjet. From sales managers to technical support staff to the CEO, he has been pleased with his experience.

If he’s stumped about a particular tree problem, he comes to them with questions. The Arborjet team has been a useful resource, Kirchner says, and he doesn’t mind leaning on them as such.

“They have really good quality products, and they’re always coming out with something new,” he says. “But you’re not just buying a product, you’re buying into a relationship as well, with someone who wants to help you do good in your business.”

Article posted in Nursery Management Magazine, Aug. 2016

Looking Ahead by Matt Berry, Tree Division Manager at Cleary Bros.

tree in hand

Fall and winter are rapidly approaching. So, it’s time to start thinking about how best to care for your communities trees so they remain a beautiful and valuable part of our landscapes. Where do we start? Tree trimming plans? Proactive disease and insect control plans? Tree fertilization? The answer is “all of the above”. Our certified arborists can assess the health of your community’s urban forest and present you with a comprehensive tree care plan. Our objective is to provide your communities with the most up to date information that will help you make informed decisions regarding the health of your trees. Give Cleary Bros. a call. We’re ready to be your tree care professionals.