Silver maple

Botanical name

Acer saccharinum

Type

Deciduous shade tree, fast growing

Size when old

Tall with a wide, spreading crown on a short trunk

Wood

Brittle, with long limbs that split at unions

Roots

Shallow, wide and aggressive near paving

Hardiness

Zones 6b to 7b across the service area

Planted for fast shade in the older neighborhoods of Reno, Sparks and Carson City, silver maples are now some of the largest trees on their lots. Their size is the issue.

How do you identify a silver maple?

The leaf is the clue. It has five deep lobes with a sharp notch between each, light green on top and silver-white underneath, so the whole tree flashes pale when the wind turns the leaves. Bark is gray and smooth on young trees and breaks into long, loose, shaggy strips on old ones. Seeds are paired winged keys that ripen in spring. The twigs droop at the ends and turn up at the tips.

• Deeply cut five-lobed leaves, silver underneath
• Shaggy, peeling gray bark on old trees
• Paired winged seeds in late spring
• Short trunk that divides low into several big limbs

Where does it grow in the service area?

It is a planted valley tree, on irrigated lots in Reno (4,500 feet), Sparks (4,400 feet), Carson City (4,700 feet) and the Carson Valley (4,700 to 4,900 feet), in zones 6b to 7b. It needs more water than the climate supplies: the nearest NOAA stations record about 7 inches (Reno-Tahoe International Airport) to about 9 inches (Carson City) of precipitation a year. University of Nevada Extension notes that high-desert urban landscapes between 4,000 and 6,000 feet have poor, gravelly soil, little organic matter and persistent drying winds, and it recommends deep, infrequent watering that reaches 18 to 24 inches for tree roots. Silver maple rarely fits the high Tahoe lots.

What goes wrong with it here?

The wood is soft and the limbs are long. A silver maple that has grown quickly carries large limbs attached at narrow angles, and snow or wind splits them. See storm and snow-load breakage. Wounds and old pruning cuts let decay in, and hollow trunks are common on old trees, see root and trunk decay.

Roots run close to the surface and wide. Near a sidewalk, curb, driveway or sewer, they lift, crack and invade. A root barrier can help in some situations, and the roots guide explains when. Cutting large roots can destabilise the tree, so ask first.

Pruning, cabling or removal: which one?

Dead wood and hanging limbs can come off at any time. Other pruning is usually done in late winter, while the tree is dormant. Useful cuts reduce the weight at the ends of long limbs and clear dead and crossing branches. Heavy topping creates weak sprouts; see why topping is not pruning.

If the trunk is sound but two main stems form a tight V, cabling and bracing may hold it. Removal is the usual answer when there is decay in the trunk or roots, large dead sections, a crack at a union over a house, or roots that are damaging a foundation or pipes. Big silver maples in tight yards are often crane-assisted removals. A certified arborist assesses the tree first, the estimate is free, and we can grind the stump. The wood and chips can be hauled or ask the office about firewood availability.