Denise Margaret Johnstone

Denise Margaret Johnstone
University of Melbourne | MSD · Department of Ecosystem and Forest Sciences

PhD, Master of Forest Science, GDAppSci(Hort), BA.

Publications

Publications (10)
Article
Full-text available
Wood structure and wood anatomy are usually considered to be largely independent of the physiological processes that govern tree growth. This paper reports a statistical relationship between leaf and bark chlorophyll fluorescence and wood density. A relationship between leaf and bark chlorophyll fluorescence and the quantity of wood decay in a tree...
Article
Full-text available
Understanding plant vitality is essential to the maintenance of healthy trees in urban environments. Tree vitality is difficult to quantify, but is usually assessed by tree growth and physiological measurements. A review of current methods used for the field measurement of plant vitality in landscape trees is presented. Methods are compared in term...
Article
Full-text available
Evaluating the wood density of standing trees quickly, cheaply and reliably with a minimum of damage is clearly of benefit to wood producers. In this study an IML-Resi F300S field tool was evaluated for prediction of wood density in Eucalyptus globulus subsp. pseudoglobulus against the high resolution SiviScan2 x-ray and image analysis instrument....
Article
Full-text available
The evaluation of wood in a tree trunk is essential for tree risk assessment, however the accurate measurement of decay is still in its infancy. A review of the current methods used for the field measurement of wood decay in landscape trees is presented. The methods are compared in terms of the damage caused to tree tissues, ease of use and the lev...
Article
Full-text available
Decayed wood is a common issue in urban trees that deteriorates tree vitality over time, yet its effect on biomass yield therefore stored carbon has been overlooked. We mapped the occurrence and calculated the extent of decayed wood in standing Ulmus procera, Platanus × acerifolia and Corymbia maculata trees. The main stem of 43 trees was measured...
Article
Full-text available
The assessment of mature urban tree vitality using physiological measurements is still in its infancy. Chlorophyll fluorescence is a method for assessing tree vitality that has potential for use in urban environments, particularly on trunk bark, which is easy to access from the ground. Here we describe how we compared bark and leaf fluorescence in...
Article
Full-text available
The recent prolonged drought in Melbourne, Australia has had a deleterious effect on the urban forest, resulting in the premature decline of many mature trees and a consequent decline in the environmental services that trees are able to provide to urban residents. Measuring the severity of tree stress and defoliation due to various climatic factors...
Article
The way a street tree is able to modify the local microclimate on pedestrian walkways may vary according to tree species according to key canopy and leaf characteristics, such as leaf angle, leaf size, canopy architecture or simply canopy density. Three similar north-south orientated streets, with three different tree species possessing different c...
Book
Full-text available
Decayed wood is a common issue in urban trees that deteriorates tree vitality over time, yet its effect on biomass yield therefore stored carbon has been overlooked. We mapped the occurrence and calculated the extent of decayed wood in standing Ulmus procera, Platanus × acerifolia and Corymbia maculata trees. The main stem of 43 trees was measured...
Article
Full-text available
Maintaining human thermal comfort (HTC) is essential for pedestrians because people outside can be more susceptible to heat stress and heat stroke. Modification of street microclimates using tree canopy cover can provide important benefits to pedestrians, but how beneficial and under what circumstances is not clear. On sunny summer days, microclima...
Article
Full-text available
Leaf chlorophyll fluorescence has been used to assess physiological stress effects in trees for at least 30 years. This paper describes a novel method for indicating tree vitality in Eucalyptus saligna Sm using bark chlorophyll fluorescence. A visual vitality index was successfully verified by comparing it with growth measurements such as total lea...
Article
Full-text available
The evaluation of decayed wood in a tree is essential for tree risk assessment in arboriculture. It is not feasible in practice to measure the amount of wood decay in all the wood of every tree. Therefore the capacity of a single measurement taken in cross section to approximate the volume of decay in the wood of a whole tree is the focus of this s...
Article
Full-text available
The evaluation of decayed wood in a tree trunk is essential for hazard tree assessment in arboriculture. In this study, an IML-Resistograph was highly successful as a field instrument in its ability to locate and predict the presence of decay in the trunk wood of eucalypts. A system for using the IML-Resistograph to estimate the area of decay in th...

About

15
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Introduction
Additional affiliations
March 1992 - July 2016
University of Melbourne
Position
  • Lecturer

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