Tree Doctor and Arborist for Calabasas and the Conejo Valley

Diagnosis first, treatment second

Most calls start with an opinion somebody has already given. A tree looks wrong, a crew has quoted for work, and the homeowner has no way to judge whether that quote is a genuine hazard or an easy sale. Answering that is where our work begins. A tree health assessment tells you what is actually wrong, how far along it is, and what the realistic options are.

That order saves money more often than it sounds like it should, because a good share of declining trees are not infected with anything. They have been pruned too hard, or watered on a schedule that suited a lawn rather than a tree, or damaged at the roots by work nobody connected to the canopy thinning two summers later.

The trees we look at here

Coast live oak and western sycamore give this side of the hills its character, and they are the two species people most often call us about. Mature oaks in particular are worth a careful opinion before anyone starts cutting, because they are slow to replace and quick to be misdiagnosed.

A useful thing to know about oaks in this part of California is what they almost certainly do not have. Oak wilt does not occur in California at all. Mediterranean oak borer is not established here either. Sudden oak death is a real disease but it belongs to the north and central coast and is not established in Southern California. If somebody has told you your Calabasas or Agoura Hills oak has one of those, it is worth asking what that diagnosis is based on before you agree to anything.

Palms are the other half of the work. Canary Island date palms are common through Westlake Village and Thousand Oaks, and unlike the desert side of our territory, this is where Fusarium wilt matters most. California's Department of Food and Agriculture describes the disease as widespread in the non-desert parts of Southern California. It has no cure, it is close to always fatal, and it travels almost entirely on pruning tools that were inside another palm earlier the same day.

That single fact changes what you should ask a crew before they start. What do they sterilize between palms, and when did they last do it. An arborist who works on palms should have an answer ready.

What we actually treat

Insects and disease are the core of it. Sticky leaves and black sooty mold mean a sap feeder, and telling whitefly from scale from aphids decides the response, because a broad spray usually makes the following season worse by killing the natural enemies along with the pest. Borers follow damaged bark rather than causing it, so the useful question is what damaged the bark. Nutrient problems are correctable and are diagnosed rather than guessed at.

We also say no. Some root diseases have no cure and some structural failures cannot be pruned away. A firm that never recommends removal is as unreliable as one that always does.

Where we work

Our office is on Agoura Road in Westlake Village, and we cover Calabasas, Agoura Hills, Westlake Village, Thousand Oaks and North Ranch, for homes and commercial properties alike.

• Agoura Hills
• Calabasas
• Westlake Village
• Thousand Oaks
• North Ranch

When it is worth calling

Call quickly for a fresh lean with soil lifting on one side, a large cracked limb over something you would mind it landing on, or a palm whose central spear pulls out easily.

Call at a normal pace for a canopy that thins a little more each year, branches dying one at a time, leaves that are sticky or blackened, or a removal quote you would like a second opinion on before you sign it. Telling a real hazard from a sales pitch is the everyday work of anarborist, and a tree doctor visit costs a fraction of a mature tree.

When it comes to your trees, you deserve the best.