Abstracts

CHAPMAN, D.J. 1984. Street trees. Am. Nurseryman 159(9): 115-116, 118-120.

There are many shade trees that adapt well as street trees, but some are rarely used. There are four important criteria for selecting street trees: 1) no species should comprise more than 5 percent of the city’s tree population, 2) the backbone of any good street tree program is native trees, 3) trees chosen should adapt well to extremes, such as low oxygen or wet soils, and 4) there is no such thing as a bad or weed tree. Remember, street trees grow in disturbed, harsh conditions. Many great urban centers were developed along rivers or bodies of water, and the prevailing soils are often heavy clay and low in oxygen. Furthermore, as population density increases, the trees are subjected to additional stresses.

HAMILTON, W.D. 1984. Sidewalk/curb-breaking tree roots. I. Why tree roots cause pavement problems. Arboricultural Journal 8: 37-44.

Landscape trees are commonly planted in the narrow strip between the curb and sidewalk. Frequently soil is compacted when curbs and sidewalks are installed. Turf and other frequently irrigated plants are also a usual part of the installation; all of which appears to favor surface rooting of the street tree. Problems of breaking sidewalk and curbs due to the proximity of tree roots is a common occurrence, especially in the close confines of urban settings. Half of the claims against a city can be from root-caused problems. The time for the problem to occur and reoccur can be short. One survey in the San Francisco area indicates ten trees, which are most often cited as root-problem trees. Where roots originate, how and where they develop, and why they grow in the proximity of pavement, are discussed.

• © 1985, International Society of Arboriculture. All rights reserved.