Tree Trimming on Yosemite Drive is a Community Blight

Many Eagle Rock residents have noticed with growing alarm the trimming of street trees on Yosemite Drive currently in progress.

Now, the truth is that street tree trimming is the ugly step-child of arboriculture. Speed is the essential requirement of the trade. Aesthetics take a back seat— and that’s when it’s done right.

Financial issues drive this: The City hasn’t got any money. The old City street tree maintenance crews are essentially gone. It’s cheaper to outsource the work to private companies. 

Or so it would seem, because when the trimming of City trees is done poorly, it becomes a blight on the community. Bad trimming also causes long-term damage to the trees. And that, in turn, costs the taxpayers money.

Two recent projects in Northeast Los Angeles illustrate the difference.

The first job was brought to my attention as a member of the Board of Directors for Northeast Trees, which takes a special interest in street trees because it has planted many of them. The first case at hand was the pruning of the ficus trees along Verdugo Boulevard in front of the Glassell Park Recreation Center. The second case is the job currently underway along Yosemite Drive.

To reiterate, street tree pruning is not the prettiest work. It’s done fast, with chainsaws rather than with pole pruners and handsaws. 

In really good tree trimming, such as the kind you want in your yard, only 20 percent to 30 per cent of the leaf coverage is removed in any one year. In residential areas there is no excuse for ignoring the guidelines of the International Society of Arboriculture.

In street tree maintenance and line clearance, that standard is relaxed to a large extent. By "relaxed" I don’t mean entirely ignored, but stretched.

The constraints on street tree pruners are manifold. They have to bring the job in on time and on budget. They have to account for vehicular traffic on one side and pedestrian traffic on the other. And they have to clear branches and foliage a certain distance from any power lines above. 

This sometimes results in funny looking trees. There will be an abrupt “L” cut out of a tree’s canopy to allow for truck or bus traffic. Or tunnels cut through the center of the canopy to allow the passage of electrical lines. 

It’s not that street tree and line clearance workers aren’t creative—they just have to march to a different drummer.

The drummer on Verdugo called a tune that resulted in a severe, but not catastrophic thinning of the ficus along that street. More than 30 percent of the leaf coverage was taken; the branches were all tipped back to a height uniform for the whole street. The change was dramatic—from deep shade to abundant sunshine in just a few days. 

Still, by the standards of the trade, it was a decent job: No large branches were stubbed off. And while there will be some die-back as a result of the pruning, it will be minimal because enough was left to enable the tree to recover.

In contrast, the drummer on Yosemite Drive must have had previous employment in a punk rock band. 

The most egregious practice of the group on Yosemite was its “stub-cutting” the ends of major branches in the trees. The reason why this is bad practice lies in a phrase I learned in tree trimming school: Trees don’t heal, they seal.

Trees don’t heal from injury the way animals—or we—do. They take advantage of their growth habit to grow around a wound, to encyst it and seal any resulting rot off from the rest of the tree. When you buy lumber, the knots you see are the end result of this process.

When trees are cut off mid-limb they are denied their natural defense. The rot that inevitably results continues down the limb and into the trunk: It does not get sealed off from the rest of the tree. 

Commercial trimming often seeks to disguise these stub cuts by cutting a branch back to something vaguely leafy. This is a parody of the real technique. When shortening a branch, it should be cut back to another branch that is proportional, at least a third the diameter of the branch being shortened. This is to ensure the smaller branch can grow around the larger one. You have to give the smaller branch a sporting chance; a branch one inch in diameter is not going to grow around an eight-inch diameter branch before the former withers and the latter rots.

The work being done on Yosemite has numerous examples of both sorts of practice. The Urban Forestry Division of the City of Los Angeles and the office of have yet to return my calls.

Other than being ugly, though, what’s the harm? 

Trees that are improperly cared for die sooner and have to be replaced. That costs money neither the City nor the rest of us have.

Their limb attachments are weaker and they become greater hazards. The potential for damage to persons and property is increased. This is especially true of soft-wooded trees such as the Jacaranda. 

Trees that are rotting are home to both insect pests as well as diseases, which end up invading the surrounding neighborhood. 

A real irony in this is that the elm trees in front of that are scheduled for work were planted by Scott Wilson, the late founder of Northeast Trees and a tireless advocate for proper tree care. 

The good that men do is oft interred with their bones. Was Mr. Wilson's work in vain?