Abstracts

CRAUL, PHILLIP J. 1986. Assess urban soil for better tree survival. Am. Nurseryman 164(7): 67-69,72-74,76,78.

Many who work with urban vegetation agree that most problems of tree survival and growth can be traced to the poor soil and site conditions presented by the urban environment. Anyone who excavates soil, especially by hand, in an urban area soon realizes that the soil material is not like the natural soil of the surrounding countryside. It has been disturbed and modified by human activity associated with urbanization. The practices of cutting and filling, digging utility trenches, stripping topsoil, and rebuilding over foundations, sidewalks and yards of previous structures create a very diverse and unpredictable material. This material has properties unlike those of a soil formed in place through natural processes over a long period. The characteristics of urban soils are as follows: *Great vertical and spatial (horizontal) variability. *A modified structure tending toward compaction. *The presence of a surface crust, which is usually water-repellent, on bare soil. *A modified soil reaction (pH), usually elevated in humid regions. *Restricted aeration and drainage. *Interrupted nutrient cycling and modified organism activity. *The presence of anthropeic (man-made) materials and other contaminants. *Modified soil temperature regimes.

CROMROY, H.L. 1986. Florida nurserymen should be wary of eriophyid mites. Am. Nurseryman 164(7): 92-94.

Nurserymen who grow shade trees and woody ornamentals are concerned with the production of clean, healthy-looking plants. Abnormal growth of plant leaves or inflorescences can reduce plant values and sales. This article is intended to acquaint growers with some of the symptoms that commonly occur with shade trees and woody ornamentals in Florida as a result of eriophyid mites. The information provided can make growers aware of the potential damage caused by these mites. Since eriophyids rarely kill their plant host and remain with a plant as it matures, young nursery stock with such abnormalities is much more of a problem than mature trees with the same affictions.

• © 1988, International Society of Arboriculture. All rights reserved.