Estimation of Water Use of Landscape Trees

Abstract

The use of a computer model of transpiration from individual tree crowns is discussed as it relates to the reciprocal effects of plants on the environment and the environment on plants. The model is shown to be useful in estimating a plant's contribution to local energy budgets as well as its water use under various environmental conditions. Model estimates of hourly transpiration rates for containergrown sugar maple (Acer saccharum) and Norway maple (Acer platanoides) saplings ranged from 6.8 g/m2/hr to 55.5 g/m2/hr, while lysimetric determinations ranged from 10.4 g/m2/hr to 63.4 g/m2/hr over a range of soil moisture conditions. The significant contribution of latent heat transfer via transpiration to the overall tree energy budget is shown by the model results as well. The model results, its areas of weakness and further research needs are discussed.

Influence of Water Stress and Restricted Root Volume on Growth and Development of Urban Trees

“…Further efforts should also be made to develop computer models of transpiration from individual tree crowns (151). Such information could be used to predict water use, to schedule irrigation, to monitor plant water stress conditions, and to assess the whole plant energy balance.…”

“…The effects of water stress in the growth and development of forest trees are also well described (66,71,72,74,95,106,109). However, relatively little research has been conducted on the effects of water stress on trees growing in an urban environment, in containers, and other confined spaces (37,111,151).…”

A Description of Urban Soils and Their Desired Characteristics

“…Vrecenak and Herrington (21) have constructed a table based on model calculations giving the estimated water loss for trees of various crown diameters and leaf area indicies (LAI), assuming a water loss of 60 g/m 2 leaf area/hr and wellwatered conditions. The example provided shows that a tree with a LAI of 4 and a crown radius of 10 meters would lose 75398 g/hr, or about 250 gallons of water in a 12-hour day.…”

Ecophysiology of Urban Trees and Their Management—The North American Experience

“…Plant assemblages, or communities, are recognized as correlating with environmental variables along gra dients of favorability (11) or tolerance (36). A lone, changes in woody plant species composition and diversity along moisture gra dients have been the subject of numerous studies (3,24,59, to cite several salient examples). Logical extensions of the basic idea have been directed " upward" to include the influence of trees on site water balance (20) and " downward" to focus specifically on phys iological differences among species (21,42,43,61).…”