Cuban Journal of Forest Sciences. 2021; May-August 9(2):285-301
Translated from the original in spanish
Diagnostic of urban trees in a section of Sancti Spíritus city
Diagnóstico del arbolado urbano en una sección de la ciudad de Sancti Spíritus
Diagnóstico da arborização urbana numa seção da cidade de Sancti Spíritus
Luis Alberto Delgado Fernández1* https://orcid.org/0000-0002-4675-1622
Adrián Rabassa Pérez2 https://orcid.org/0000-0002-4757-5747
Ana Gertrudis Trocones Boggiano1 https://orcid.org/0000-0001-5769-2165
Ildefonso Orrantia Cárdenas1 https://orcid.org/0000-0003-1904-2879
1University of Sancti Spíritus "José Martí Pérez". Sancti Spíritus, Cuba.
2State Forest Service. Delegation of Agriculture. Palmira, Cienfuegos. Cuba.
*Corresponding author: email@example.com
The current research was carried out with the aim of diagnosing the situation of the urban trees in a section of Sancti Spíritus city. For this, an area of 25.39 ha was selected, where three plots were established, in which the inventory and classification of tree species in terms of taxonomy, origin, uses, type of location, state of development and phytosanitary was carried out, unrest problems were identified, and the volume of wood from those in the state of high trunk development was also estimated. In the studied section, 1 522 trees were counted, belonging to 59 species, 55 genera and 32 families, of which Fabaceae and Meliaceae were the best represented with 10 and 8 species respectively. Casuarina equisetifolia L. and Hibiscus elatus Sw. specified the largest number of individuals with more than 200 in each case. Timber species predominate (55.93 %), of which 722 examples are in high trunk development state, with an estimated volume of wood of 711.280 m3 in general. 62.71 % of the counted individuals are evergreen, and 49.16 % correspond to autochthons species. Trees in groups predominate (63.4 %); 85.28 % have a good phytosanitary status while 61.76 % need some type of silvicultural care. The main problems identified were location of trees in compact soils; damage to infrastructures caused by root systems and proximity to electrical and telephone wiring. Finally, some measures are proposed to contribute to the improvement of the identified problems.
Keywords: Urban trees; Cassification; Conflictivity; Species; Running; Management; Planning.
La investigación se realizó con el objetivo diagnosticar la situación del arbolado urbano en una sección de la ciudad de Sancti Spíritus. Para ello, se seleccionó un área de 25,39 ha donde se establecieron tres parcelas, en las que se realizó el inventario y clasificación de las especies arbóreas en cuanto a taxonomía, origen, usos, tipo de emplazamiento, estado de desarrollo y fitosanitario; se identificaron los problemas de conflictividad y estimó el volumen de madera de los ejemplares en estado de desarrollo fustal alto. En la sección estudiada, se contabilizaron 1522 árboles, pertenecientes a 59 especies, 55 géneros y 32 familias, de las cuales, Fabaceae y Meliaceae son las mejores representadas con diez y ocho especies respectivamente. La Casuarina equisetifolia L. e Hibiscus elatus Sw. presentaron el mayor número de ejemplares con más de 200 en cada caso. Predominan las especies maderables (55,93 %), de las cuales, 722 ejemplares se encuentran en el estado de desarrollo fustal alto, con un volumen de madera estimado de 711,280 m3 en general. El 62,71 % de las especies son perennifolias, y el 49,16 % corresponde a especies autóctonas. Predominan los árboles en grupos (63,4 %); el 85,28 % presenta buen estado fitosanitario, mientras que el 61,76 % necesita algún tipo de atención silvicultural. Los principales problemas identificados fueron ubicación de árboles en suelos compactados; daños a infraestructuras provocados por los sistemas radiculares y la cercanía al cableado eléctrico y telefónico. Finalmente, se proponen un conjunto de acciones para contribuir al mejoramiento de los problemas identificados.
Palabras clave: Arbolado urbano; Clasificación; Conflictividad; Especie; Gestión; Manejo, Planificación.
A pesquisa foi desenvolvida tendo como objetivo de diagnosticar a situação da arborização urbana em um setor da cidade de Sancti Spíritus. Para tal, procedeu-se a elaboração de um inventário em três parcelas pré-estabelecidos numa área de 25,30 ha. As espécies arbóreas da área selecionada foram classificadas de acordo a taxonomía, uso, função, localização, estado de desenvolvimento e fitossanitário. Foram identificados problemas de conflito e estimado o volume de madeira dos espécimes em estado de alto desenvolvimento do caule. Na seção estudada, foram contabilizadas 1.522 árvores, pertencentes a 59 espécies, 55 gêneros e 32 famílias, das quais Fabaceae e Meliaceae são as mais bem representadas com 10 e 8 espécies, respectivamente. Casuarina equisetifolia L. e Hibiscus elatus Sw. apresentaram o maior número de exemplares com mais de 200 em cada caso. As espécies madeireiras predominam (55,93 %), das quais 722 espécimes encontram-se em estado de alto desenvolvimento do caule, com volume de madeira estimado de 711.280 m3 em geral. 62,71 % dos indivíduos contados são perenes, e 49,16 % correspondem a espécies autôctonas. Árvores em grupos predominam (59,46 %); 85,28 % apresentam bom estado fitossanitário enquanto 61,76 % necessita de algum tipo de cuidado silvicultural. Os principais problemas identificados foram a localização das árvores em solos compactados; danos a infraestruturas causados pelos sistemas radicais e proximidade de fiação elétrica e telefônica. Por fim, propõe-se um conjunto de medidas contributivas para a melhoria dos problemas identificados.
Palavras-chave: Árvores urbanas; Classificação; Conflito; Espécies; Gestão; Manejo; Planejamento.
In mid-21st century, it continues to be a challenge for city managers and planners to ensure that cities are economically, socially and environmentally sustainable, resilient and capable of providing the ecosystem services required by citizens for a good quality of life.
According to FAO, (2017), urban and peri-urban forests can respond to this challenge because of their enormous contributions to environmental sustainability, economic viability and habitability of settlements, however, for that, they must be well managed and designed. In this sense, Duval et al., (2020) state that knowledge of the dynamics of the urban environmental system is essential to achieve these goals.
In the selection of suitable species for establishment in the urban area, it is necessary to take into account a series of factors such as, for example, the availability of space, soil conditions, environmental and social requirements of the dynamics of the city, as well as establishment and maintenance costs (Alvarado et al., 2014). In spite of the well-known benefits of urban trees in terms of ecological balance, by exercising regulatory and purifying functions of an environmental nature, sheltering and protecting fauna and flora, as well as guaranteeing an improvement in the quality of life of the citizens (Alonso et al., 2019); the establishment of tree species has different connotations with respect to the development of infrastructure, since in some cases, this can limit the development of plant species (Vargas 2020) or on the contrary, there may be species that affect the integrity of the infrastructure, generating situations of incompatibility that lead to deterioration or damage to them, or worse, put the safety of people or infrastructure at risk (Morales 2018).
Sancti Spíritus does not escape from this problem, and as in several Cuban cities, one can see in different areas, the planting of tree species without taking into account harmonization criteria between the requirements of the urban habitat and those of these plant species. The way in which urban trees are managed, as well as many of the design solutions adopted for their establishment, have a negative impact on their quality. Many areas that were originally conceived with spaces for trees currently show flaws in design, planning and management that lead to the progressive deterioration of their image and limit not only their potential for use by the population, but also the important environmental function of trees in the city.
Based on the above, this research was developed with the objective of diagnosing the current state of urban trees in a section of Sancti Spíritus characterized by two of the most important recreational parks in the city.
MATERIALS AND METHODS
Location and generalities of the study
An area of 25.39 ha was selected for this research, which is located at coordinates 21p 55'35.09" N 79p 26'03.63" W. (Figure 1). Two of the city's most important recreational parks are located there: the Agricultural and Livestock Fair and the Provincial Zoo.
Figure 1. - Delimitation of the study area and establishment of the diagnostic polygons
The delimitation of the study section, as well as the determination of its area, was carried out using the Global Positioning System (GPS). Three (3) plots were established within the same area to facilitate the tours and recording of information; the criteria for the selection of these plots coincided with the work areas established by the Communal Services Company for the planting and care of urban trees in Sancti Spíritus, who normally use the term "block" to designate them.
The areas of each plot are:
Both the Agricultural Fair, as well as the Zoological Park, was considered plots in all their extension. The zero point or starting point for the routes was set at the intersection between Avenida de los Mártires and Calle Telo Sánchez. Only areas in the state sector were worked on.
During the tours of the plots (field work), the direct visual inspection method was used to determine the following aspects:
Conflict problems: in this case, three types of risks were determined, assuming as such, those threats or vulnerabilities that can end in a serious event (Amézquita and Gavilán, 2020):
a) Risks that represent possible damage caused by trees due to different circumstances,
which entail situations in which these affect infrastructures due to their own growth habits.
b) Risks that represent possible damage to trees, due to factors that may affect their normal development and quality of life.
c) Risks that represent possible damage to human beings, due to the weakening and breakage of trees, the excessive fall of leaves and flowers, or those that due to poor management or poor placement limit visibility on roads. In all these cases, they become the cause of problems or accidents that affect people in different ways.
Other activities developed during the tours were:
The following aspects were determined by means of a desk study, using the method of consultation of bibliographic sources and specialized personnel, as well as reviews of herbarium materials:
Several photographs and botanical samples were taken of the species not known to the authors for later identification.
From the dendrometric measurements taken and using Excel software (2016), the volume of wood in general, by species (timber) and by families was determined. The calculation was performed only for specimens in the high fustal stage of development because they are the most susceptible to being replaced during management activities; the following mathematical equation was used for this purpose (Equation 1).
d= diameter (cm).
h= height (m).
f= shape coefficient.
RESULTS AND DISCUSSION
A total of 1522 specimens of arboreal bearing, belonging to 59 species, 55 genera and 32 families were recorded in the study section (Table 1).
Table 1. - Families and species present in the study area, with other relevant data
Legend: Ex= Exotic; Au= Autochthonous; Perennif. = evergreen; Caducif. = deciduous
From the information presented in the table above, the following aspects can be summarized:
Families with the highest number of species
In Figure 2, it is illustrated that the families Fabaceae, Meliaceae, Bignoniaceae, Boraginaceae and Palmaceae are the best represented in the study section according to the number of species (Figure 2).
Figure 2. - Families represented by a higher number of species
These results are similar to those obtained by Machado et al., (2016), who studied areas of heritage value in Santiago de Cuba and found a higher representativeness of the Fabaceae family with ten species. For their part, Leal et al., (2018), in an area similar to the one selected for this study in Nuevo León, Mexico, recorded 2066 individuals, with greater representativeness for this same family.
Species with the highest number of specimens
As shown in Figure 3, C. equisetifolia and H. elatus were the species with the highest abundance of specimens with more than 200 in each case, followed by D. lutescens, S. macrophylla and T. grandis, with more than 100 each (Figure 3).
Figure 3. - Species with the highest abundance of specimens
The largest number of individuals corresponds to an exotic species (C. equisetifolia), considered by several authors as invasive, which also generally has a sparse crown and does not produce showy flowers, this species is more acceptable for the establishment of plantations for timber, energy and/or restoration purposes, especially in sites where open-pit mining is carried out, as it forms the soil. This result indicates planning problems, since urban tree plantations are often established based more on the availability of plants in nurseries, rapid growth and the great plasticity of some species than on the function they should perform in the places where they are located. H. elatus, a native species, has a good crown, showy flowers and is highly appreciated for its multiple uses, including medicinal, timber and ornamental uses.
Similar results were obtained by Bonilla-Vichot et al., (2019) when they carried out studies in a section of the city of Pinar del Río, where they found an abundance of specimens of this species, while Sosa et al., (2011), carried out a similar investigation in the municipality of Guisa, Granma, and found a greater number of casuarina specimens in the area studied.
Classification of species by origin
Although the section selected for the study shows a balance between exotic species (50.84 %) and native species (49.16 %), the former are represented by a greater number of specimens with 928 (60.97 %). According to the results obtained in similar research at national (Sosa et al., 2011; Jiménez et al., 2015; Machado et al., 2016; Bonilla-Vichot et al., 2019) and international levels (Morales 2018; Leal et al., 2018), native species are less eligible when planning and managing urban tree planting; which is mainly due to the greater volume of information that exists on the management and propagation of exotic species, the plasticity of many of them, and their rapid growth.
Classification of the species by the permanence of the foliage
The 62.71 of the species present in the area are evergreen. For Urban Forestry it is important to take this aspect into account, since the placement of trees with such characteristics should be prioritized in places where their function is to provide shade, as well as in areas where the excessive leaf and flower fall typical of deciduous species could become a risk for passers-by.
Classification of species by their main use
Of the 59 species identified 55.93 % are timber; 28.81 % are ornamental; 13.55 % fruit and one species (1.71 %), M. oleifera, is primarily medicinal.
Currently, there is a tendency to enhance the establishment of fruit trees as part of urban trees, since, according to FAO, (2017), the presence of these species is very important; taking into account the role they can play in food sovereignty and security. On the other hand, considering that one of the areas studied is the Zoo, contemplating the planning of the establishment of fruit trees would have a significant impact as a nutritional supplement in the diet of the animals.
Other relevant information obtained in the study was as follows:
Trees per plot
Classification of the specimens according to their stage of development:
Of the 1 115 specimens belonging to timber species, it was found that 722 (64.75 %), are in high forest stage of development; 27.13 % in low forest; 6.01 % in sapling and 2.11 % in latizal.
It is important to observe the state of development of the trees located, since, as Matamoros, (2019) refers, the planning of pruning and other cultural attentions that will demand a greater number of resources as this is more advanced, which can greatly increase the cost of maintenance of urban areas, depends to a great extent on this. The importance of this aspect has also been highlighted by Carbajal, (2018), for whom the longevity of trees can become a high-risk factor if they are not well managed.
Diameter at 1.30 m in the studied tree stand ranged from 9 to 125 cm, while height values ranged from 3 to 21 m. These results are similar to those obtained by Sosa et al., (2011) in the city of Guisa, Granma province, who report diameters from 3.4 to 95 cm and heights from 1.5 to 25 m.
The total estimated volume in the study section was 711.280 m3. The families Casuarinaceae, Malvaceae, Verbenaceae and Meliaceae presented the highest values in the species C. equisetifolia, H. elatus, T. grandis and S. macrophylla respectively (Table 2).
Table 2. - Estimated wood volume values by species
The behavior by plots was as follows:
The result is closely linked to the greater number of specimens of timber species present in the third plot, most of which are in an over-mature state.
Physical and health status
The tree mass studied is healthy, as 85.28 % of the specimens show no visible damage to their external constitution. Disease and mechanical damage to trunks and branches were observed in 8.67 % and 2.89 % of the individuals.
These results coincide with those of Sosa et al., (2011), Morales (2018) and Matamoros (2019), who found in their study areas most of the specimens with good physical and sanitary condition. Guerra et al., (2010) in areas of the city of Pinar del Río, found the most frequent damage to be mechanical, bark and diseases.
Despite the good condition of the stand, 940 trees, representing 61.76 %, require some type of silvicultural intervention, especially partial pruning and improvement of holes. These attentions are not only necessary to minimize risks, but also to improve the development conditions of the trees.
Classification according to the type of location
Group trees predominate (63.4 %), in which, H. elatus, C. equisetifolia, T. grandis and S. macrophylla are the most represented species. Isolated trees (21.41 %) and those aligned with flowerbeds (13.2 %) are the other most observed site types in the study section. This result is consistent with the presence in the study section of two recreational parks, and educational centers such as primary schools, children's circles, the Faculty of Agricultural Sciences of the UNISS among others.
The results of the conflictivity analysis and which in turn represent potential damage or risks are summarized below
Risks representing damage caused by trees
Risks such as those mentioned in this group, have been reported by Morales (2018); Bonilla et al., (2019); Amézquita and Gavilán (2020). While Ramos (2019), refers that these are the main problems or conflicts that occur in urban environments in most countries.
Risks that represent damage caused to trees
These types of risks have been cited in similar research by Guerra et al., (2010); Morales, (2018) and Matamoros (2019).
Risks that represent harm to humans
These types of conflicts have been mentioned as frequent in urban trees (Matamoros 2019 and Weisz 2020).
Recommended actions to eliminate or minimize the conflict problems identified in the study section
The urban trees in the section of the city of Sancti Spíritus selected for the study are abundant and diverse; their physical and sanitary condition is good, however, there are problems in terms of design, planning and management.
The families represented by a greater number of species are Fabaceae and Meliaceae; while C. equisetifolia and H. elatus present the greatest abundance of individuals.
Although there is a balance between the number of exotic and native species, the former are represented by a greater number of specimens.
In the study area there is an abundance of evergreen and timber species, which represents an advantage in terms of environmental services.
Through the study of site type, a predominance of trees in groups was determined, represented mainly by the species H. elatus, C. equisetifolia, T. grandis and S. macrophylla.
The conflict analysis made it possible to identify a group of risks that represent possible damage to infrastructures, to the trees themselves and to human beings; this led to the proposal of measures that not only make it possible to manage them, but also to outline communicative strategies that favor awareness on the part of the population.
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Conflict of interests:
The authors declare not to have any interest conflicts.
Luis Alberto Delgado Fernández: Conception of the idea, literature search and review, instrument making, instrument application, compilation of information resulting from the instruments applied, statistic analysis, preparation of tables, graphs and images, database preparation, general advice on the topic addressed, drafting of the original (first version), review and final version of the article, article correction, authorship coordinator, translation of terms or information obtained, review of the application of the applied bibliographic standard.
Adrián Rabassa Pérez: Conception of the idea, literature search and review, instrument making, instrument application, compilation of information resulting from the instruments applied, statistic analysis, preparation of tables, graphs and images, database preparation, general advice on the topic addressed, drafting of the original (first version), review and final version of the article, article correction, authorship coordinator, translation of terms or information obtained, review of the application of the applied bibliographic standard.
Ana Gertrudis Trocones Boggiano: Conception of the idea, literature search and review, instrument making, instrument application, compilation of information resulting from the instruments applied, statistic analysis, preparation of tables, graphs and images, database preparation, general advice on the topic addressed, drafting of the original (first version), review and final version of the article, article correction, authorship coordinator, translation of terms or information obtained, review of the application of the applied bibliographic standard.
Ildefonso Orrantia Cárdenas: Conception of the idea, literature search and review, instrument making, instrument application, compilation of information resulting from the instruments applied, statistic analysis, preparation of tables, graphs and images, database preparation, general advice on the topic addressed, drafting of the original (first version), review and final version of the article, article correction, authorship coordinator, translation of terms or information obtained, review of the application of the applied bibliographic standard.
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Copyright (c) 2021 Luis Alberto Delgado Fernández, Adrián Rabassa Pérez, Ana Gertrudis Trocones Boggiano, Ildefonso Orrantia Cárdenas