Environmental Designs Landscape Blog: California Sycamore

November 30, 2006

Sycamore Tree Report

Job site:

Residence

Newport Beach, Ca.

Client:

On November 17, 2006, I inspected one California Sycamore (Platanus recemosa) tree in the front yard, located at the residence under construction.

Overview

The Sycamore is a mature tree 35’ tall x 25’ wide with a 24” DBH trunk located in the front yard 12’ from the corner of the house. The tree has been severely topped in the past. The tree is infested with the Sycamore Borer. The tree has sustained recent construction damage. The trees overall health at the time of inspection is moderate.

Site observations

The Sycamore tree is growing in sandy loam soil with a neutral PH of 7.0. The PH reading was obtained with a hand probe in the field. No irrigation system is present at that time. The tree was severely topped in the past with large cuts on all the major branches. New growth has grown back with possible weak branch connections. Suckers have sprouted around the trunk.

Photo 1 & 2. Sycamore at 1234 Any Ln., Newport Beach, Ca

Avoid Topping Trees

Topping, also called stubbing or dehorning, is the drastic heading of large branches in mature trees. Main limbs are often sheared as with a hedge, leaving stubs. Topping is a poor pruning practice sometimes used to shorten tall trees, remove hazardous or diseased limbs, or to prevent interference with overhead utility lines.

Drastic pruning is rarely justified simply because trees are believed to be too tall. Removing extensive canopy may not leave enough foliage to manufacture sufficient food and may cause roots to die and the tree to decline. The large wounds left by topping often fail to close and are susceptible to internal decay and attack by wood-boring insects. Topping encourages growth of branches weakly attached below the cut, which become susceptible to wind breakage.

Prune trees properly when they are young to minimize the need for severe pruning when trees mature. Instead of topping, selectively remove upper limbs back to lower lateral branches. This proper method is more time consuming and expensive, but avoids future expense from improper pruning and provides a more attractive, healthier, and safer tree.

Sycamore Borer

Synanthedon resplendens

The tree is infested with Sycamore Borer Synanthedon resplendens as evidenced by the patchy, rough bark and frass at the base of the trunk.

Photo 3. Frass at base of trunk.

Photo 4. Sycamore Borer larva.

The Sycamore Borer occurs in the Southwest. It is prevalent in sycamore and also infests oak and ceanothus. Adults emerge from May through July after overwintering as larvae or pupae in tunnels in bark. Adults resemble yellowjacket wasps. The male is mostly yellow with a brownish black head and black bands on the body. Its legs are yellow, except for black along the margins on the portions nearest to the body. The wings are mostly clear with orangish to yellow margins. Adults display wasplike behavior by intermittently running while rapidly fluttering their wings.

Eggs are laid on bark, and the grublike larva is pink to white with a reddish brown head. When mature, it tunnels near the bark surface and leaves a paper-thin layer of outer bark through which the pupa protrudes just before adult emergence. Borer larvae cause bark to appear rough, and sawdustlike material sometimes accumulates around the tree base. The insect has one generation a year.

Sycamores tolerate extensive boring by this insect, and generally no control is recommended. Parasitic nematodes can be applied to kill larvae and are most effective in spring when tunnel openings are largest. A persistent pesticide applied to bark when adults are active also provides control, but this is generally not recommended unless trees are of such high aesthetic value that damage cannot be tolerated.

Roots

Multiple roots had been exposed and some had been cut or split due to a recent grade change. The exposed roots were located 12” to 24” below existing finish grade approximately 4’ from trunk.

Photo 5. Existing grade change.

Photo 6. Existing cut and damaged roots.

Roots support the tree, store energy reserves, absorb water, and with the help of root-associated fungi, absorb elements that are essential for life. There are woody roots and nonwoody roots. The woody roots are large support roots and smaller fine roots, The nonwoody roots are nonmycorrhizal or mycorrhiza associated with fungi.

The anatomy of roots is basically the same as trunks. The roots have a vascular cambium, bark and wood. There is no pith in the center of roots. The roots usually have more parenchyma cells and fewer fibers. The distinction between growth rings is not as clear in roots as it is in trunks. Roots do not have a normal, colored, core of heartwood. The anatomical changes from trunk to root occur in a transition zone at the base of the tree. There is seldom an abrupt anatomical change from trunk to root. If there is a pith center, the section is trunk and not root.

Roots, like branches and twigs, also age and die. As roots die, boundaries form that resist the inward spread of pathogens. When nonwoody roots die, a corky periderm boundary forms that separates the nonwoody infected root from the healthy woody root.

Image 7. Plan showing construction fence location, wall locations and potential root water irrigation head locations.

Tree Summary and History

Platanus racemosa California sycamore

Robust native of California foothills and Coast Ranges; grows near streams in the wild. Deeply lobed leaves turn dusty brown early in autumn; in mild coastal climates, they hang on until new growth starts.

Leaf: Alternate, simple, deciduous, 5 to 10 inches long, palmately lobed (usually 3-5 lobes) with lobes about half as long as the leaf; hairy when young; petioles are long, swollen at their base, and hairy.

Flower: Monoecious but imperfect, male and female flowers are tiny and borne in dense, round heads (like fuzzy marbles on a string).

Fruit: Golf ball sized heads of tufted achenes; 3 to 7 hang on a long pendulous stalk designed to fracture at maturity; seeds are wind dispersed.

Twig: Slender and covered with numerous fine hairs when young; becoming smooth and reddish brown with age. Terminal buds absent; lateral buds conical.

Bark: The most striking feature of this tree. Young greenish-gray bark exfoliates leaving almost pure white inner bark; older bark is thicker (1 to 3 inches), furrowed, and dark brown.

Form: A medium to tall tree (30 to 100 feet tall) that sometimes reaches 50 feet in diameter. Crown is open and rounded.

Photo 8. Examples of Platanus racemosa, California Sycamore tree parts.

Recommendations

· Install a construction fence around the tree at the drip line. Refer to partial site plan (Image 7. Page 4) for location.

· Keep the fenced area clear of building materials, waste, and excess soil.

· Avoid grade changes within the drip line except where necessary to construct footings and retaining walls. Where possible use grade beams for the wall footings to minimize root damage.

· When excavating for the footings take care not to crush, break or tear the roots. Roots are to be cut cleanly and perpendicular with bypass pruner or tree saw.

· No wound dressings are to be applied to the cuts, as this technique has been proven ineffective at preventing decay.

· Back fill excavation with native soil.

· Deep water the root zone when the top 18” of soil becomes dry. Infrequent deep watering is preferable to constantly moist soil.

· Hire a professional tree trimming company that employs certified arborists for future pruning. The tree will need constant care to repair past pruning damage.

· Prune suckers at base of tree.

· Apply organic fertilizer per manufacturer’s specifications.

· Apply 2” thick top dressing of mulch around base of tree.

· Sycamores tolerate extensive boring by the Sycamore Borer, and generally no control is recommended. Parasitic nematodes can be applied to kill larvae.

Summary / Conclusion

Thank you for calling on my services with your questions regarding your Sycamore tree. Protect the tree from construction damage by erecting a fence around the tree at the drip line. Prune damaged and exposed roots. Apply mulch. Apply organic fertilizer. Deep-water tree as needed. Properly prune tree canopy in the future. The tree will protect itself from decay and pathogens by compartmentalizing the cuts to the roots.

With proper protection and care the Sycamore tree will survive the construction process and remain healthy for many years.

If you have any questions concerning this report or if I can be of further service to you, please call me at any time.

Craig de Pfyffer

Certified Arborist

Certificate # WE-6533A

Expiration Date: 12-31-2006

Disclaimer

Although all the recommendations in this report are based on sound and accepted horticultural practices, the author cannot be held responsible for the final outcome of the recommendations, or any liabilities associated with this project. Tree inspections, in this case, do not cover internal cavities, structural defects, or diseases with non-visible symptoms.

ENVIRONMENTAL DESIGNS ARBORIST

P.O. Box 247, Laguna Beach, CA. 92652

Tel: (800) 811-3010 Fax: (800) 811-3014

Craig@environmentaldesignsarborist.com