Trees are living elements interspersed throughout our cities, and are considered by economists to be "fixed assets". Though they form part of our cities they do not have a set price as normally understood and calculated within the framework of a perfectly competitive market. The main aim of this article was to compare the main methods developed in the USA (North American) and Europe (Finnish, Swiss, French and Capitalisation methods) for determining the monetary value of urban trees in the town of Santiago del Estero, northeastern Argentina. The values of eight specimens of the most abundant species in the city (Brachychiton populneum, Citrus auriantum, Grevillea robusta, Jacaranda mimosifolia, Sapindus saponaria, Tabebuia impetiginosa, Thevetia peruviana, and Tipuana tipu) were calculated using all five methods mentioned above and the mean values returned compared by ANOVA. The results suggest a methodology combining both capitalisation and parametric indices might be the most useful way of determining the value of city trees.

Urban trees perform a number of basic functions related to the environment and the welfare of city dwellers (ecological, recreational, psychological), although their benefits are not readily quantifiable. However, in certain situations, it is essential to assign an economic value to the trees. There are currently various methods for valuing the benefits of trees and greenspaces in human settlements, including statistical methods, the travel cost method, contingent valuation, the hedonic pricing method, and integrated methods. However, these methods are not used in official valuations of urban trees; in these cases, appraisal methods are used. The aim of this paper is to study the appraisal methods used for their detailed features and the possibilities of their application. The main conclusion of this review is that there are a number of methods with different types of application. The best method is selected according to tree location, type of land ownership, and the availability of data. Methods with a higher degree of applicability are CTLA, a parametric method of low difficulty, and Contato, a mixed method of medium difficulty. In any case, it is advisable to increase efforts to objectify the correction index in the case of parametric and mixed methods.

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Obtención de valores unitarios mediante el método de árboles-tipo para la tasación del arbolado urbano: aplicación en Santiago del Estero (Argentina) y Madrid (España)Obtaining unit values through the type-trees method for urban trees appraisal: application in Santiago del Estero (Argentina) and Madrid (Spain) SUMMARYThis work presents a tool for assessing urban trees which allows getting two basic requirements in public management: reduction of costs and simplicity. For this purpose, a methodology based on a multivariate statistical analysis is presented. It allows establishing type-trees in urban trees areas representing and grouping homogenous species and dasometric characteristics simultaneously. Field work was carried out in two different locations: the city of Santiago del Estero (Argentina) and the Arboretum of Madrid Forestry Engineering School (Spain). The methodology groups the trees together in tree groups through the discriminant analysis technique. For each group, the most frequent species in Santiago del Estero were: Citrus auriantum, Tabebuia impetiginosa and Tipuana tipu. In Madrid they were the Ligustrum japonicum, Platanus x hybrida and Populus alba var. bolleana. One type-tree per group was determined, which was representative of all urban trees of that group. The economic value of each type-tree was calculated for each area by the capitalization method. Their unit value is the appraised value of the specimen per unit size. The price per unit of size can be applied to any urban tree in its group, allowing a quick calculation of its basic economic value, low cost and applicable to most valuation formulas. The methodology described allows simplifying the calculation of the economic value of urban trees located in different locations.Key words: tree appraisal; discriminant analysis; municipal management; urban silviculture. RESUMENEste trabajo ofrece una herramienta para valorar el arbolado urbano, cumpliendo dos requisitos básicos de gestión pública: reducción de costes y sencillez de aplicación. Para ello se presenta una metodología basada en técnicas de análisis estadístico multivariante que permite determinar árboles-tipo en zonas con arbolado urbano que representen y agrupen simultáneamente especies y características dasométricas homogéneas. Se han analizado dos poblaciones diferentes: el centro urbano de Santiago del Estero (Argentina) y el Arboreto de la Escuela Técnica Superior de Ingenieros de Montes, de la Universidad Politécnica de Madrid, campus Moncloa (España). La metodología clasificó de forma automática los árboles en tres grupos mediante análisis discriminante. En cada grupo se selecciona la especie más frecuente, que para el caso de Santiago del Estero, fueron Citrus auriantum, Tabebuia impetiginosa y Tipuana tipu, mientras que en Madrid fueron el Ligustrum japonicum, Platanus x hybrida y Populus alba var. bolleana. Se determinaron los árboles-tipo, uno de cada grupo, para cada espacio verde, representativos del conjunto de árboles urbanos. Se calculó el valor económico de los ...