ABSTRACT Persian gardens have been an essential component of Iranian urban and architectural history for almost 2500 years. Persian gardens continued to provide provisioning services (i.e. food production) until the twentieth century when their status and role switched from productive to ornamental gardens. In this study, we conducted interviews and field surveys in a Persian garden in eastern Iran to understand how the use of edible plants has changed since the end of the 1970s. Although the production function is not the primary role of this garden, the results demonstrate that numerous edible species have been reintroduced. In addition, the marketing and branding of the fruits cultivated in the garden could be a source of income for the garden’s maintenance. From an ethnobotanical and germplasm conservation point of view, this garden features key cultivars and plants that have been used in traditional Iranian medicine.

ABSTRACT The costs of maintaining an urban street tree over its lifecycle have been considered in cost models. One used in Australia is a typical relationship between the cost and functional and aesthetic benefits of the urban shrub mass. But are these curves typical of larger, long-lived urban street trees growing under Australian conditions? The costs of maintaining an urban street tree under Australian management regimes, including purchase and planting costs of a common street tree species, herbicide and mulching costs, the cost of irrigation over the first summer after spring planting and of formatively pruning the young tree were calculated based on data obtained from Australian local government agencies. The research-modelled management of an urban tree under five scenarios based upon planting a 2–3 m tall tree with a safe useful life expectancy of 50 years. Scenarios included annual maintenance, regular pruning on a 5-year cycle after 15 years and a major arboricultural intervention in the final decade. The impact of longer lifespans of 100 or 150 years was also modelled. The curves demonstrated that costs associated with a street tree are high in the first 2–3 years of its life but much higher in the final year of life leading to removal but differed in shape from other models. The lifetime costs of maintaining a street tree depending on the management scenario are between AUD$2800 and AUD$6220 or AUD$56 and AUD$124.40 per annum. Doubling the lifespan of a street tree reduces the annual management cost by 30%.

ABSTRACT Branch junctions are typically strengthened by the production of dense wood with a tortuous grain pattern in their axils (axillary wood). The strong association found between natural braces in trees and bark-included branch junctions set below them suggests there may be a causal relationship: that if a branch junction receives little mechanical stimulation due to being naturally braced, little or no axillary wood will be formed and bark is occluded instead. To investigate this relationship, sixty branch junctions in young specimens of aspen (Populus tremula L.) were braced with horticultural wire and their development contrasted with sixty “controls” where no bracing was applied. After three years, 95% of the braced branch junctions exhibited included bark, whereas only one control junction developed included bark and that was found to be natural braced. This is the first recorded instance where bark-included junctions have been knowingly created by artificial means. The results point to a causal relationship between natural bracing and the formation of bark-included junctions, which has implications for tree management. This study also provides evidence that axillary wood should be categorised as a reaction wood, as its formation requires specific mechanical stimulation, and due to its distinct anatomical and mechanical properties.

ABSTRACT The amenity tree valuation method CAVAT apparently gives reduced weight to future benefits, similarly to discounting. Discounting future conditions allows calculation of a value per year per square centimetre of tree basal area, on the premise that tree planting was rationally done. The resulting value ascribed to a target tree is much lower than that calculated by CAVAT. CAVAT’s value is the same as given by the “rational” procedure if trees were predicted not to grow. The “rational” perspective provides a reasoned estimate of CAVAT’s avowed objective of calculating a compensation replacement value for lost trees. CAVAT itself seemingly calculates over-generous compensation. The “rational” protocol’s apparently low value may be adjusted upwards to recognise incomplete planting survival, conditions of high cost, overheads and, sometimes, defective discounting. These, and any neglect of the value of subsequent replanting and of people’s particular associations with trees, may undervalue fair financial recompense, especially when no compensation planting is made. However, some of these factors would revise CAVAT values upwards too, so the gap between outcomes might remain. Neither protocol translates from a cost basis to a full amenity benefit of trees.

ABSTRACT Wind-load estimations have been part of research on tree biomechanics and windthrow for several decades and are crucial for some safety assessment methods in commercial urban forestry and arboriculture. Examples of those methods are SIA, SIM, Finite Element Method, Dynatim and Arwilo. The goal of the present study was to see if an extremely simple mathematical model, based on stiff wind turbines, would be able to reproduce the results of some of those software packages. A model such as this, licence-free and at no cost, would be attractive to practitioners in their daily work. Simulation of, and comparison with, the commercial software was very satisfying. Agreement, with a correlation coefficient of 0.99, was almost perfect for more than 220 trees and a palm. Moreover, and as the correct interpretation of these methods is crucial, remarks are made too which can assist practitioners in their tree and palm risk assessments.

This article refers to:The implications of recent English legal judgments, inquest verdicts, and ash dieback disease for the defensibility of tree risk management regimes

ABSTRACT Over the course of history, oak trees have played a significant role in the natural landscape and built environment. While providing essential resources that sustain wildlife and even humans, they have aptly developed a legacy reflective of their importance across cultures. They inspire place names, emerge in stories and art, and appear on flags and coins. Their wood products, prominent in the architecture of ships, buildings, hand tools, and more, serve as a testament to their durability. Associated with qualities of endurance and longevity, the oak tree presents as a popular symbol. It is recognised as the national tree in the U.S., where oaks grow prolifically in a variety of environments. With such a reputation and many qualities resembling those of other desirable shade trees, oaks have become some of the most preferred, recommended, and beneficial species in U.S. urban forests.

With a paper by Adesoye and Dondofema (2021) this issue of the Arboricultural Journal brings into focus matters of tree health in relation to risk in avenue trees. Nelson, Nelson, and Montgomery (2...

ABSTRACT It is well accepted that particulate matter (PM) can affect human health detrimentally. Chronic and prolonged exposures to particulate matter with an aerodynamic diameter ranging between 2.5 and 10 microns (PM10), 0.1 and 2.5 microns (PM2.5) and less than 0.1 microns in size (UFPM), have been associated with cardiopulmonary diseases. PM is ubiquitously present in urban settings, while primarily absent in forest environments primarily due to the direct interception of airborne pollution particles by trees. Both short- and long-term exposure to trees in forested environments is associated with lower blood pressure and inflammation, as well as enhanced immune function. Additionally, exposure to volatile organic compounds (VOCs) actively released by trees is associated with improved health through enhanced natural killer cell activity, reduced inflammatory responses, and reduced psychological stress. This article presents the results of a literature review on the harmful health effects of air pollution in urban environments, and the potential of forested environments to promote health and disease prevention.