Arboriculture & Urban Forestry 38(4): July 2012 tree is located in the city or in a rural area; and finally, a fac- tor indicating the size (C), with values from 1 to 55 for nor- mal circumferences of between 30 and 900 cm respectively. The North American method (CTLA 1992; CTLA 2000) gave rise to the idea of a “base value” as an expression of the unit price of a section of trunk, and considers the maximum value of a tree to be the product of this base value multiplied by the area of the section of the trunk. Corrector indices (species, condition, and location) maintain or reduce this value, but never increase it. [8] Value = [trunk area (cm2) × basic price cm2 × condition × location The North American method only considers the utilitarian as- pect of trees—initially the value of their wood—but in recent years tree value has also been estimated in terms of energy sav- ings, air pollution, and other environmental functions. There is an adaptation of this method in the UK known as CAVAT (Neilan 2008). CAVAT can increase, decrease, or cancel the tree’s base value by the corrector index. This method has soft- ware that enables automatic calculation of value (CAVAT 2012). The Finnish method (Caballer 1999) uses a base value for each genus and species, established for each square centimeter of a section of trunk taken 1 m above the ground. The value of any individual tree is then found by multiplying its cross sectional area at this height by this base value. This is then corrected using a location index (according to whether the tree is in the city or in the country; the value of a city tree is always increased by this step) and a discount parameter based on the specimen’s state of health and conservation. The final value is therefore expressed as: [9] Value = S × P × L × E where S is the section of the trunk, P is a value established and tabulated per cm2 of section (which varies accord- ing to species), L is a variable defining the location (open country 1.3, forest 1.8, city 2), and E represents the con- dition of the tree on a descending scale, from 1 for com- pletely healthy to 0.2 for a very ill and weakened specimen. The formulaic expert method (FEM) (Jim 2006) selects six primary criteria (dimension, species, tree, condition, location, and outstanding consideration) branched in 45 secondary criteria. Each primary criteria is standardized to carry equal weight (maxi- mum aggregate scored is 100) and are then all added together. The tree’s monetary value is the result of multiplying the aggregate score of a tree by a monetary assignment factor (MAF). This fac- tor is derived from the three-year average sale price per m2 of me- dium-sized residential flats. The expression for valuing a tree is: [10] Value = (D+S+T+C+L+O) × (100/135) × MAF The scores are computed using additive of second- ary value. The secondary values are obtained by se- lecting from a multiple-choice list of options. D is the score for dimension of the trees and is calculated by adding the scores associated with height, crown, trunk, and relative size (maximum value 25). S is the score for the spe- cies, including aesthetic value and rarity (maximum value 15). T is the score for tree specimen and includes the quality of the tree structure and its service as habitat (maximum value 20). C ] × species 133 is the score for condition and includes the symptoms of pests and diseases, the scores of condition of the trunk, branches, foliage, and roots (maximum value 25). L is the score for lo- cation and includes abundance, suitability, danger, environ- ment, and environmental benefits (maximum value 20). O is the score for outstanding characteristics and is calculated by adding the score of outstanding features, such as size, bo- tanical interest, or historical association (maximum value 25). Capitalization Methods Capitalization methods evaluate trees by applying indexes, ma- trix tables, and other simplified forms, and are aimed at mak- ing calculations easier for people who are not necessarily ex- perts in the subject. Multiplicative methods do however include the age of the tree as a basic variable, as measured by the size and life-expectancy indexes. The interest rates are the rate of growth of the tree and the accumulated average annual growth rates are distributed in different ways throughout the life of a tree. There are two basic methods of capitaliza- tion: value based on the replacement costs and val- ue based on maintenance costs (Caballer 1999). The equation used as the basis for replacement cost methods is: cost of annual maintenance, Cr is the cost of remov- [11] Value = Pr + (Cm where Pr is the market price of the tree, Cm al, and k is the factor determined by the age of the tree. The equation used as the basis for maintenance cost methods is: [12] Value = (1 + i) t - t0 (Pr where i is interest rate, t-t0 Ct + Ct ) / P is the number of years during which maintenance tasks are performed, Pr is the market price, is the planting costs, and P is the probability of rooting. Mixed Methods The ICONA method (López Arce 1975) was proposed for calculating compensation in the case of loss of or- namental trees. It uses six indices, which when multi- plied with each other, give the final value of the tree. The species and varieties are classified into eight types, and each of these is assigned a particular coeffi- cient (A). This classification uses as a reference the sales price in the respective nurseries, based on the hypoth- esis that this price accurately reflects the degree of diffi- culty in reproducing and growing a particular tree species. The index for aesthetic and functional value and health (B) establishes four values, ranging from 1 for evidently diseased or severely mutilated specimens, to 10 for outstanding, healthy and vigorous trees. The authors’ proposal is noteworthy for the distinc- tion it makes between trees planted in groups or arranged in rows. The method includes a double-entry table for the location in- dex (C) with a combination of elements that provides nine differ- ent locations. Values are assigned according to the size of the city measured by the number of inhabitants, and to the tree’s visual surroundings (from rural to urban or with special significance). It also proposes a rarity index (D). The number of trees of a particular species in an area is registered on a scale ©2012 International Society of Arboriculture × k) + Cr is the
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