Local arborist battles beetles

By From page A4 | March 15, 2013


ARBORIST CHAD DYKSTRA treats a Ponderosa Pine tree for the Western Bark Beetle. The nicotine-based insecticide is harmless to plants and animals, but lethal to bugs, and has come under fire recently as a risk to the health of honey bees. Courtesy photo

My wife and I have spent the last decade living with a collection of mature oaks and pines on two and a half acres outside Placerville. We’ve made steady improvements to the house and have no plans to leave … ever.

Our favorite tree is a proud Black Oak that shades our front deck from the afternoon sun. Without warning it dropped a third of its massive canopy into the front yard in October.

We sought advice from local tree trimmers, and also got bids to cut down two Ponderosa Pines that had fallen victim to the bark beetle. I would have cut them myself, but they were surrounded by other mature pines which, on closer examination, were also infested, but still fighting.

Web research on bark beetles was discouraging. One site advocated spraying the entire tree and all its branches with a highly toxic pesticide. Most advised mass cutting and burning.

A progression of tree men told us the lopsided oak would fail in the first big storm. The prognosis for the infested pines was no better. Like the oak, they all needed to come down. It would be expensive.

The last call I made was to Foothill Tree Service. Enter arborist Chad Dykstra, 40, who’s become the front man for the company his father James founded in 1965.

The younger Dykstra prescribed a regimen of limb cutting to reduce the big oak’s remaining canopy. Severe weather might still bring the old girl down, he said, but minus a few pounds, she stood a good chance of outlasting us.

Despite the crews of wiry guys with climbing ropes and chainsaws he employs, Dykstra insists the business isn’t about cutting trees. Foothill Tree’s primary mission is “arboriculture, making things grow,” he said.

He specializes in diseases and insects that damage trees, and testifies as an expert witness in tree-related court cases and insurance claims, often in Southern California, where drought-weakened forests were decimated by the bark beetle over the last 15 years.

A horrific fire in Ventura County torched 91,000 acres and 1,000 homes in 2003, fueled in large part by the dead pines, according to local news reports.

The county recently lifted a decade-long state of emergency in its forests, citing the end of the drought coupled with a quarter billion dollar effort to remove nearly 700,000 dead trees.

In other areas the problem remains acute, as warmer winters sustain beetle colonies from season to season and allow the pests to migrate to higher elevations, where trees lack natural defenses against them.

Healthy trees recognize an attack and fight back by secreting resin that expels the burrowing bugs.

Drought weakened trees have little sap to spare for such a defense and remain vulnerable throughout the western U.S., according to the Forest Service’s 2011 Western Bark Beetle Strategy report.

It estimated that 10,000 dead trees fall to the ground every day in northern Colorado and southern Wyoming alone, threatening buildings, power lines and people. Three quarters of British Columbia Lodgepole Pine forests were dead or dying in 2011, according to the report.

Foothill Tree adopted a Pine Bark Borer protocol using a systemic insecticide in 2010 and has treated thousands of pines since. In the vast majority of cases, the beetle hasn’t returned, he said. A similar protocol for the Fir Engraver Beetle is equally effective, returning even severely infested trees to health.

Once the bark beetle is established, most trees die without treatment, he said.

He uses a rating system to help his clients determine which trees to save. At $95 per tree, the treatment decision is often budgetary.

Stage evidence of disease recovery chance:

0 — Healthy tree: 100 percent
1 —  Pitch tubes and dead branch tips (flagging): 90 percent
2 —  Top dead or dying:  90 percent
3 —  Top dead and pitch tubes: 50 percent
4  — Mostly dead: Low
5 —  Dead: 0 percent.

Our infested stand of pines measured up thusly: two dead or dying, two others with dead tops and a half dozen stage 1s.

They all showed evidence of the woodpeckers, which proide a natural defense against the beetle, cratering the bark in quest of beetles or less threatening bugs.

But their collateral damage exposes the tree to other pests, providing an open door to the tree’s delicate cambium layer, said Dykstra. Worse still, the birds use the holes as part granary, part farm. They store acorns, which eventually decay, attracting other invasive insects, which the woodpecker returns and harvests.

The cambium is located just beneath the bark, and houses the tree’s vascular system, including a hard-working, super thin membrane called the “xylem,” which is the prime mover of water and nutrients, aka sap, from the roots up into the tree.

The nutritious xylem is the bark beetle’s favorite food and also its preferred breeding ground, which also makes it the tree’s weak link. Once the xylem is compromised — or consumed — the tree starts to die.

The xylem is a relay sprinter, designed by nature or God to rush gallons of nutrients to the top of its tree while fending off attackers for a single growing season before handing off to a rookie xylem then retiring to become the tree’s outermost ring.

“Your trees’ damaged xylems will be replaced next year,” said Dykstra in November. “But we have to kill the beetle and its larvae.”

Beetle larvae hatch in April and May, which makes February and March ideal treatment months.

The tree’s weak link is also the beetle’s. Dykstra treats the xylem with a diluted nicotine-derived insecticide cocktail, served up with a “surfactant” chaser, which acts like a wetting agent, thinning the compound, dramatically increasing absorption.

The most common delivery vehicle is a root drench. Injection has also become increasingly popular, see sidebar.

Dykstra sprayed the surfactant-laced cocktail directly onto the bark of our trees. It passes through the bark quickly, he explained, mixes with the sap, then hitches a ride to the treetop in the xylem, letting the tree’s normal transpiration process do the heavy lifting.

The goal is to minimize “chemical trespass” outside the tree, he said.

A single, properly applied treatment spreads the medicine throughout the tree within 30 days.

He also poured between three and five gallons of a diluted mixture at the base of each trunk, to be absorbed by the roots over the next few weeks, killing beetle larvae along the way. The medicine stays in the tree for at least a year, he said.

Dykstra acknowledges that the compound can be harmful to bee colonies if not used properly, which is why he never uses it on flowering plants or near water.

The neonicotinoid family of pesticides were approved in the 1990s as a safer alternative to prior insecticides, safe on humans, pets and plants, but toxic to adult insects on ingestion, and, importantly, to larval insects on contact.

They were quickly adopted for a wide variety of agricultural uses.

In recent years beekeepers and environmentalists have accused neonicotinoids of contributing to bee colony collapse, and praised a recent European Union proposal to ban three specific compounds: Imidacloprid, Clothianidin and Thiamethoxam on crops that affect bees: sunflowers, rapeseed, corn and cotton.

They also criticized the Environmental Protection Agency for not taking similar measures in this country.

Neither County Ag. Commissioner Charlene Carveth or Farm Bureau Director Valerie Zentner thought the problem was acute in El Dorado County, an observation borne out by a trip to the Placerville Fruit Growers Association, which carries neonicotinoids in concentrations up to 100 times what’s on the shelf at Home Depot.

The general public can purchase the compounds with a signature, but only arborists, ours in particular, are currently buying them, according to the guy behind the counter.

Dykstra insists that neonicotinoids are absolutely safe when used properly. “You can take these products away from the general public,” he said, “but let those of us who know how to use them safely continue to do so.”

He warns that he’ll need his most effective weapons in what he predicts will become a high-casualty war with even more destructive pests from the far east which have already established themselves in southern California.

Local trees are unprepared for the ambitious foreign pests, and will likely suffer over the next decade, he added.

“These new bugs have no natural predators and our trees have no innate defense against them,” he said. “They’ve killed more than 50,000 oaks in Southern California and are headed this way.”

Dykstra’s crew removed our two worst pines and treated the others. Like most people with tree problems, we should have acted sooner. He put it bluntly: “Dead trees breed more dead trees.”

He’s frustrated by the attitude of many rural residents who heat their home with wood and see the loss of trees as little more than a source of fuel.

“Trees are natural air filtration systems,” said Dykstra. “They gobble up acid rain and pollution, and are an important part of the local ecosystem. We need to protect them.”

Our big oak will apparently be filtering the air for at least one more season. She survived a snow load recently without complaint. The jury is still out on the pines.

For more information or to schedule a consultation, contact Chad Dykstra at 530-621-1772 or visit

Mike Roberts

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