Tree Survival in Cities: The Extent and Nature of the Problem

Abstract

The results of a survey of newly planted trees of eleven cities in the North of England are presented. The composition of the tree populations of these towns is seen to be dominated by a few species. The potential for growth is high, yet the average levels of shoot extension are remarkably poor. High levels of tree death are found in some towns. Water and nutrient stress are highlighted as major causes of the poor condition of urban trees. Vandalism and other causes of physical damage are much less important. It is argued from the evidence that much of the trouble must be attributed to the way techniques of planting and maintenance are applied in practice, rather than to any inherent problems of sites or trees in general.

Analyzing growth and mortality in a subtropical urban forest ecosystem

“…Urban tree mortality has been the subject of relatively few studies, but some studies of street trees in the temperate northeastern and western US and northern England have shown that mortality was related to tree condition, size, age, land use, water and nutrient stress, socio-economic status, community participation, and maintenance practices (Foster & Blaine, 1978;Gilbertson and Bradshaw, 1985;Nowak, McBride, & Beatty, 1990;Nowak et al, 2004;Sklar & Ames, 1985). For instance, Nowak et al (1990) observed an average morality of 19% for trees along boulevards in Oakland, California, with higher rates (34%) observed adjacent to apartments and public greenspaces.…”

Biological, Social, and Urban Design Factors Affecting Young Street Tree Mortality in New York City

“…The published study with the largest sample size reports on observations of 10,000 newly-planted trees in northern England and finds 9.7% mortality after one year (Gilbertson and Bradshaw 1985). The researchers draw attention to the many factors potentially affecting mortality levels such as stock quality, planting technique, and maintenance regime, but do not attempt to directly link any of these phenomena to tree mortality rates.…”

“…Vandalism, as measured by the observation of broken branches in the canopy or a broken main stem, is an important factor in the mortality of urban trees (Gilbertson and Bradshaw 1985;Nowak et al 1990;Pauleit et al 2002;Roman 2006); adjacent land use can negatively affect street tree populations (Nowak et al 2004;Roman 2006); and some species of trees fare much better than others as street trees (Gilbertson and Bradshaw 1990;Miller and Miller 1991;Sydnor et al 1999;Pauleit et al 2002). Few studies have analyzed the role of physical urban design factors such as traffic volume or the tree's location within the streetscape on mortality rates.…”

Mortality and recruitment in an urban forest (Forest Park in Portland, Oregon) between 1993 and 2003

“…Tree mortality and recruitment are important parameters in determining how succession will proceed, but limited studies have been done in urban areas. Most of the urban studies have assessed street trees (Gilbertson andBradshaw 1985, Nowak et al 2004), which do not necessarily respond similar to trees in natural forested urban areas. Several workers have reported reduced recruitment in urban forests (Greller 1975, Airola and Buchholz 1984, Fahey 1998, Lehvävirta and Hannu 2002, Zipperer 2002, Bertin et al 2006, Broshot 2007, and some have reported increased tree mortality in urban areas (Davis 2004, Nowak et al 2004, Carreiro and Tripler 2005, Broshot 2007).…”