Determination of forest cover in 10 farms under traditional agroforestry
systems in the Corotú area of El Empalme canton, Guayas.
Determinación de la cobertura forestal en 10 fincas bajo sistemas agroforestales tradicionales
en el recinto Corotú del cantón El Empalme, del Guayas
Diana Elisseth Nivela Peralta
Master, Independent Forestry Consultant,
Quevedo, Ecuador, dnivela@cfi.com.ec
https://orcid.org/0000-0002-0886-1863
Cesar Alberto Cabrera Verdesoto
Master, Forestry Engineering Career,
Universidad Estatal del Sur de Manabí,
Jipijapa-Ecuador,
cesar.cabrera@unesumn.edu.ec,
https://orcid.org/0000-0001-5101-3520
Darwin Marcos Salvatierra Pilozo
Master, Forestry Engineering Career,
Universidad Estatal del Sur de Manabí,
Jipijapa-Ecuador,
darwin.salvatierra@unesum.edu.ec,
https://orcid.org/0000-0002-2659-4471
Abstract
The present research was aimed at determining the forest cover in ten farms with traditional agroforestry
systems, based on the characterization of each of them (farms).A planimetric survey and zoning of the
agricultural areas with vegetation cover was carried out, where the common name, diameters,
commercial and total height of the trees greater than 10 cm DBH of the adult stand were recorded
through a census, subsequently the data were separated into diameter classes with 10 cm intervals,
determining the basal area and commercial volume, for the taxonomic identification of the species the
Angiosperm Phylogenetic Group (APG) classification system was used. A total of 524 forest species
associated with agroforestry systems were identified and classified into four different types according
to their production components. The floristic diversity corresponds to 35 species, 33 genera, and 19
families, the most abundant species was Cordia alliodora (Ruiz & Pav.) Oken, being the Boraginaceae
family the most abundant, the Ecological Importance Value Index (IVI) was shown to be most
representative for Ceiba pentandra (L.) Gaertn, with 77.57%; the Shannon index determined a medium
diversity in SAF1, SAF2 and SAF4, unlike SAF3 that showed low diversity, within the Jaccard analysis
that 0.05% was obtained, indicating that there is little similarity of species among the SAF.
Keyword: Agroforestry; trees; crops; relationship.
dnivela@cfi.com.ec
Received July 22, 2021
Approved: December 18, 2021
46
Resumen
La presente investigación se encaminó en la determinación de la cobertura forestal en diez fincas con
sistemas agroforestales tradicionales, con base en la caracterización de cada uno de ellos (fincas). Se
efectuó un levantamiento planimétrico y zonificación de las áreas agrícolas con cobertura vegetal,
donde se registraron mediante un censo el nombre común, diámetros, altura comercial y total de los
árboles mayores a 10 cm de DAP de la masa adulta, posteriormente los datos se separaron en clases
diamétricas con intervalos de 10 cm, determinando el área basal y volumen comercial, para la
identificación taxonómica de las especies se empleó el sistema de clasificación de Angiosperm
Phylogenetic Group (APG). Se identificaron 524 especies forestales asociadas a los sistemas
agroforestales, para ello se clasifico en cuatro tipos diferentes de acuerdo a sus componentes de
producción. La diversidad florística corresponde a 35 especies, 33 géneros, y 19 familias, la especie
más abundante fue Cordia alliodora (Ruiz & Pav.) Oken, siendo la familia Boraginaceae la más
abundante, el Índice de Valor de Importancia Ecológica (IVI) se mostró más representativo para Ceiba
pentandra (L.) Gaertn., con 77,57%; el índice de Shannon determinó una diversidad media en los SAF1,
SAF2 y SAF4, a diferencia del SAF3 que presentó diversidad baja, dentro del análisis Jaccard que se
obtuvo 0,05% esto indica que existe poca similitud de especies entre los SAF.
Palabras clave: Agroforesteria; árboles; cultivos; relación.
Introduction
The expansion of monocultures such as: banana, African palm, industrial plantations, cocoa CNN-51
and others have caused the reduction of native forest species, therefore, it was of great importance to
conduct studies on forest cover in traditional agroforestry systems, to determine the types of agricultural
associations with the management of the shade of tree species. Therefore, it was proposed to determine
the forest cover in 10 farms, whose objective was to characterize the agrarian systems and their
relationship with the trees.
The role of conservationist farmers of agricultural germplasm and associated woody plants is known
within the science of agroforestry as traditional agroforestry systems, because it is the tradition of
cultivating and maintaining agrarian spaces in combination with native species. The approach of
traditional peasant agriculture makes it possible to diversify crops in small areas, maintaining rotation,
soil conservation and local seeds. The scarce information of studies on traditional agroforestry systems
has an impact on the sustainability of agroforestry production systems, so the social, ecological and
economic benefits of FFS are unknown, in farms where there are no trees the negative effects of natural
agents (rain, wind and sun) increase, water retention capacity decreases, soil leaching occurs, these
effects may be greater in areas where short-cycle crops are grown, intensive soil use and absence of
forest cover (Benavides, 2013, p.133).
Agroforestry techniques are used in various regions with diverse ecological, economic and social
conditions. The environmental conditions favor vegetation, where there is moisture and the soils are
fertile, agroforestry systems can be very productive and sustainable (Musálem, 2002, p. 98).
Ecuador is considered to have a high rate of biodiversity of flora and fauna, due to the ecological and
geographic conditions where it is located. Despite its small territory, it is a mega-diverse country in
terms of agricultural, livestock, aquaculture and forestry production associated with traditional
agroforestry systems (CORPEI, 2012).
http://centrosuragraria.com/index.php/revista, Published by: Edwards Deming Institute,
Quito - Ecuador, January - March vol. 1. Num. 12, 2022, This work is licensed under a
Creative Commons License, Attribution-NonCommercial-ShareAlike 4.0 International.
https://creativecommons.org/licenses/by-nc-sa/4.0/deed.es
Nivela, Cabrera, Salvatierra 2022
January - March vol. 1. Num. 12 2022
The canton of El Empalme has a land area of 1,139.22 km² where we find a great diversity of timber,
agricultural, fruit, medicinal, and small livestock species; forming part of the traditional agroforestry
systems that are options to reduce the risk of climate change. The combination of trees, crops and
animals allows for sustainable agricultural production (PDOT, 2015).
The Guayas parish is one of the largest in the canton of El Empalme, 73.70% of the rural area has
monocultures and crops such as rice, corn, cocoa, coffee, bananas, natural grasses and crops associated
with traditional agroforestry systems.) Land use change in recent years has been drastic and traditional
agroforestry systems are tending to disappear, affecting the food security of rural families (PDOT,
2015).
The study area does not have a work that collects all these traditional peasant experiences, it is
considered agricultural production land where the owners encourage the cultivation of various forest
species associated with dispersed agroforestry systems as a contribution of wood, shade, fruits, among
other services.
Materials and methods
The present study was carried out in the Corotú precinct, La Guayas parish, El Empalme canton, Guayas
province, 10 farms with traditional agroforestry systems were chosen, considering the methodology
proposed by (Moreno et al., 2013), where a characterization of the different agrarian systems associated
with timber species, fruit trees, perennial, annual and short-cycle crops was carried out to determine the
types of FAS, so the planimetric surveys and zoning of the farms were carried out, through a forest
census of the adult mass of trees and the various types of associations, where the typology that allowed
differentiating the FAS was determined.
The dasometric parameters of the forest and fruit species were recorded to determine the richness and
tree diversity of the systems by means of indices. The forest species were identified by scientific genus
and family names, the formulas of absolute and relative abundance, absolute and relative frequency,
absolute and relative dominance and the importance value index (IVI) were used to calculate the
evaluation of the horizontal plant structure, while the vertical structure was calculated using the
diametric classes, Shannon's index, Simpson's index, Sorensen's index and Jaccard's index.
Figure 1. Location of the agroforestry systems study area.
48
Selection of agroforestry systems and field registration
The criteria highlighted by (Navarro et al., 2012) are the structure-function, socioeconomic nature and
ecological range of the system, the criteria by (Moreno et al., 2013), of a characterization of agroforestry
systems in Mexico were also analyzed, as well as the criteria proposed by (Prado, 2009) on traditional
agroforestry systems in Loja, Ecuador. Considering the studies of the previous authors, 10 farms were
selected. In each productive unit, a planimetric survey and zoning was carried out. For the identification
of forest species, the common name, commercial and total height, as well as the phytosanitary status of
all trees greater than 10 cm DBH were recorded. All species were geo-referenced with GPS, using a
field sheet for forest inventories. The Angiosperm classification system (APG, 2016) was used for
species taxonomy.
Evaluation of horizontal plant structure
To calculate the vegetation structure within the farms with traditional agroforestry systems, data on
height in m. and diameters in cm were recorded for individuals with DBH > 10 cm. These variables
were used to determine Absolute Abundance (Aa), Relative Abundance (Ar), Absolute Frequency (Fa),
Relative Frequency (Fr), Absolute Dominance (Da), Relative Dominance (Dr) and Importance Value
Index (IVI). The diversity indices of a similar work proposed by (Poma, 2013) were taken as references.
a) dasometric parameters
•
Basal area and volume
The following formula was used to calculate the basal area and volume per tree:
𝐴𝐵 =
𝜋
4
𝐷
!
Where:
AB = basal area (m²)
D = diameter (m)
π = constant
V = AB
!
× H
"
× F
#
Where:
V = tree volume (m³)
AB = basal area (m²)
Hc = height (m)
Nivela, Cabrera, Salvatierra 2022
January - March vol. 1. Num. 12 2022
Ff = form factor (0.7)
•
Diameter classes
In order to provide a better representation of the forest cover on the farms, it was categorized in diameter
classes with 10 cm intervals: C1 (10.00 - 20.00); C2 (20.01 - 30.00); C3 (30.01 - 40.00); C4 (40.01 -
50.00) and C5 (>50.01) cm of DBH, this allows us to know in which class is the highest frequency of
flora diversity indexes in traditional agroforestry systems.
b.) Ecological parameters
•
Absolute abundance (Aa)
For the calculation of absolute abundance, the number of individuals per species was taken as follows.
Aa = Number of individuals of a species
•
Relative abundance
For relative abundance, we considered the number of individuals of the species divided by the sum of
the absolute abundance of all species, multiplied by one hundred.
Ar = x 100
Where:
Ar = Relative abundance (%)
Aa = Absolute Abundance
•
Absolute frequency (Fa)
The following formula was used to calculate the absolute frequency:
Fa = No. of number of sampling units (farms) where a species occurs.
•
Relative frequency
The absolute frequency of the species divided by the sum of the absolute frequency of all species,
multiplied by one hundred, was considered.
Fr = x 100
Where:
especieslastodasdeAade
especieladeindividuosden
å
º
especieslastodasdeFa
aespecieladeFa
S
50
Fr = Relative frequency
Fa = Absolute frequency
• Absolute dominance (Da)
To determine absolute dominance, the basal area of the species was considered using the following
expression:
Da = basal area of the species (Ab).
•
Relative dominance
Dr (%) = x 100
Where:
Dr = Relative dominance (%)
Da = Absolute dominance
AB = Basal area
•
Importance value index
IVI = Ar + Fr + Dr
Where:
(IVI) = Importance Value Index (%)
Ar = Relative abundance
Fr = Relative frequency
Dr = Relative dominance
Indices for assessing vegetation diversity and similarity
To determine plant biodiversity within agroforestry systems, the Shannon and Weaver, Jaccard and
Simpson indices were used (Finol, 1971).
•
Shannon - Weaver indexes (H')
especieslastodasdeAb
especieladeDa
S
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January - March vol. 1. Num. 12 2022
Being:
Where:
S = Number of species (riqueza de especies)
Pi = Proportion of individuals of species i with respect to the total number of individuals, i.e., the relative
abundance of species i.
Ni = Number of individuals of species i
N = Number of all individuals of all species
•
Simpson's Index (S)
S = 1/s (Pi)2
Where:
S = Simpson's Index
1/s = Probability that random individuals from a population come from the same species.
Pi = Proportion of individuals belonging to the same species.
•
Sörensen's Index
Sörensen's index indicates the similarity of four samples.
𝐼𝑎 =
2𝑐
𝑎 + 𝑏 + 𝑐
3𝑥3100
Where:
Ia = Sörensen species association index (%).
a = Number of species appearing in the first plot.
b = Number of species occurring in the second plot.
c = Number of species occurring in both plots.
Pi =
ni
N
H`#
= −#
∑
𝑝𝑖#𝑙𝑜𝑔2#𝑝𝑖
!
"#$
52
For the interpretation of the Simpson, Shannon and Wiener index, the values proposed by (Pla, 2006)
were used.
Table 1. Simpson, Shannon and Wiever's Index
•
Jaccard Index
The Jaccard index was used to determine if there are similarities or dissimilarities between the species
that make up the vegetation structure within the traditional agroforestry systems to be evaluated.
𝑰𝑱3
(
%
)
=
𝐂
𝐀 + 𝐁 − 𝐂
𝐱3𝟏𝟎𝟎
Where:
IJ = Jaccard Index (%)
A = Number of species in community A
B = Number of species in the community B
C = Number of common species in both communities
Result
Table 2. Table of areas of the owners of the 10 farms with traditional agroforestry systems.
N°
Owners
Total Has.
N°
Owners
Total Has.
1
Adela Romero
14,24
6
Ernestina Coello
3,96
2
Alfredo Fuente
2,77
7
Hugo Ibarra
2,53
3
Alfonzo Zambrano
3,9
8
Lorenzo Cedeño
16,8
4
Bertha Jimenez
1,38
9
Nelson Nivela
3,96
5
Emilio Solórzano
4,79
10
Tomaza Romero
1,61
The farms where the research was conducted comprise an area of 55.94 hectares, which are relatively
small, 20% are between 14 to 17 hectares and 80% are less than 5 hectares, so the agricultural systems
must be diverse to have economic sustainability, they are also under pressure from large extensions of
banana, African palm and industrial plantations, which would put in the future the disappearance of
agroforestry systems.
Values
Interpretation
0,0 - 1,6
Low diversity
1,7 - 2,89
Average diversity
> 2,90
High diversity
Source: (Pla Laura. 2006).
Nivela, Cabrera, Salvatierra 2022
January - March vol. 1. Num. 12 2022
Categorization of traditional agroforestry systems
The traditional agroforestry systems presented crops associated with banana area, coffee, national cocoa
and CCNN-51 with timber and fruit species interspersed with annual cycles such as rice, corn, peanuts
and beans, for a better classification the reference of (Mendieta el al., 2007) was taken, who propose as:
SAF1 Trees in plots or dispersed in perennial crops; SAF2 Family orchard; SAF3 Crops in alleys and
SAF4 Trees in line. Reference was made to ( Moreno el al., 2013) who identified zones or sites with
different types of land use and resource utilization on traditional agroforestry systems in Mexico, where
20 different names for PFS were identified with their spatial location, the intensity of management of
the system and the ecological and biocultural context of the communities.
Floristic diversity in traditional agroforestry systems.
The farms are made up of valuable timber species and edible fruit trees, which have been cultivated
through natural regeneration, trees planted in line and internal divisions of crops, where a total census
was conducted for each farm, where 504 individuals, 19 families, 33 genera and 35 species were
recorded. in the 10 farms with traditional agroforestry systems, which are sources of economic income
at different times of the year obtaining a stable production of various crops and in its final turn the use
of trees either by thinning or harvesting.
The total area of the ten farms corresponds to 55.94 ha, 50% of the farms are next to each other and the
others are separated by other properties that do not have agroforestry systems. A total of 504 individuals
were found, which represents 9 trees/ha.
Abundance of botanical families in agroforestry systems.
The abundance of individuals of the families found in the evaluated farms was for Boraginaceae with
126, Moraceae with 70, Lauraceae with 64 and Polygonaceae with 59 and with an uncommon notoriety
for Bignoniaceae, Muntingiaceae and Myrthaceae with one species.
Absolute and relative abundance
The species with the highest number of individuals was Cordia alliodora (Ruiz & Pav.) Oken. With
126 and the species that showed the lowest number of individuals were Ceiba pentandra (L.) Gaertn,
Raphia taedigera Mart., Pouteria caimito (Ruiz & Pav.) Radlk, Tabebuia guayacán (Seem.) Hemsl,
Artocarpus altilis (Parkinson ex F.A. Zorn) Fosberg. With 1 individual respectively.
Absolute and relative frequency
The species found in the four types of agroforestry systems were Cordia alliodora, Mangifera indica,
Pholidostachys dactyloides, as opposed to the trees Artocarpus altilis, Artocarpus heterophyllus,
Cecropia peltata, Ceiba pentandra, Chrysophyllum cainito, Erythrina poeppigiana, Ficus aculeata,
Inga spectabilis, Muntingia calabura, Ochroma pyramidale, Ocotea sp, Otoba gordoniifolia, Pouteria
caimito, Raphia taedigera, Schizolobium parahyba, Spondias dulcis , Syzygium malaccense, Tabebuia
guayacan.
54
26
3
17
1 1
126
7
58
64
7
20
11
70
1
3
59
2
42
6
0
20
40
60
80
100
120
140
ANACARDIACEAE
ANNONACEAE
ARECACEAE
BIGNONIACEAE
BOMBACACEAE
BORAGINACEAE
CAESALPINACEAE
LAMIACEAE
LAURACEAE
LEGUMINOSAE
MALVACEAE
MELIACEAE
MORACEAE
MUNTINGIACEAE
MYRISTICEAE
POLYGONACEAE
RUTACEAE
SAPOTACEAE
URTICACEAE
DIVERSITY AND ABUNDANCE OF SAF
FAMILIES
SPECIES
Absolute and relative dominance
The species with the highest absolute and relative dominance within the agroforestry systems was
Cordia alliodora. With 8.58 and 58.09; and the species with the lowest dominance were Tabebuia
guayacan . With 0.01 and 0.04 followed by Syzygium malaccense. With 0.02 and 0.22, and Raphia
taedigera. With 0.05 and 0.16 correspondingly.
Value and Importance Index (IVI)
The species with the highest percentage of Value and Importance Index within the agroforestry systems
was: Ceiba pentandra with 77.57% because the value belongs to a single individual Mangifera indica
with several individuals presented 81.55% and Tectona grandis with 79.02%, while the species with
the lowest percentage of IVI are: Tabebuia guayacan with 3.45% followed by Geonoma cuneata with
3.51% and Zanthoxylum riedelianum with 3.53% comparatively.
Diversity and density of traditional agroforestry systems.
The diversity and density of traditional agroforestry systems is represented by the Boranginaceae,
Moraceae, Polygonaceae, Lauraceae, Sapotaceae, Lamiaceae and Anacardaceae families, due to the fact
that landowners still adopt to conserve the germplasm of valuable timber as a forest resource on their
farms.
Figure 2. Diversity of families and species in the 4 types of agroforestry systems.
Nivela, Cabrera, Salvatierra 2022
January - March vol. 1. Num. 12 2022
Table 3. Diameter classes of wood in the ten farms.
Diameter classes (cm)
Basal area (m
2
)
Volume (m
3
10,0-20,0
2,49
9,75
20,01-30,0
9,24
45,80
30,01-40,0
11,20
57,40
40,01-50,0
7,91
42,41
> 50,01
17,06
160,63
Totals
47,90
315,99
Intervals of 10 cm were used as reference for the categorization of diameter classes and to determine
the values of basal area m
2
and volume m
3
.
Shannon's and Simpson's index of agroforestry systems
The Shannon index showed values corresponding to medium diversity in SAF1, SAF2 and SAF3, while
in SAF4 it showed a value corresponding to low diversity. Simpson's index in SAF1, SAF2, SAF3 and
SAF4 represents an unequal distribution, so a very abundant species Cordia alliodora was found in all
agroforestry systems.
Table 4. Shannon and Simpson's index of the four types of agroforestry systems.
Sorensen's Index
Sorensen's index 0.01 indicates that the similarity and association indexes are low among agroforestry
systems.
Jaccard Index
The Jaccard index is 0.05, which shows that there is little similarity of species among the agroforestry
systems found in the ten farms.
Variables such as number of individuals, family, species and genus change from one zone to another
due to the ecological and geographical conditions and the size of the agroforestry systems they present.
This agrees with (Moreno el al., 2013) from a study conducted in traditional agroforestry systems in
Mexico. Traditional agroforestry systems present crops associated with banana area, coffee, national
cocoa and CCN-51 with timber and fruit species interspersed with annual cycles, which for (Torres et
al., 2014) determines that through the integration of trees on farms improves the agricultural landscape,
diversifies and sustains production to increase the social, economic and environmental benefits of
farmers at all levels.
Diversity
SAF1
SAF2
SAF3
SAF4
Shannon
2,46
2,14
1,73
1,58
Simpson
7,64
5,93
4,57
3,41
56
The most abundant family within the agroforestry systems was: Boraginaceae with 126 individuals
followed by Moraceae with 70 individuals, data that does not agree with the research of (Zambrano,
2012) where the most dominant family was: Malvaceae followed by Arecaceae and the work done by
(Chacón, 2017) the most abundant family was Leguminosae and Rutaceae.
Within the study area the agroforestry system of greater importance was for SAF 1 (trees in plots or
dispersed in perennial crops), which does not agree with the research of (Zambrano, 2012) and (Chacón,
2017) conducted in the canton Valencia province of Los Ríos, where the most important agroforestry
system was mixed orchards and trees associated with pastures.
The most predominant species in the agroforestry systems was Cordia alliodora followed by Persea
americana and Triplaris cumingiana. This is partly consistent with the work done by (Martínez, 2011).
The species with the highest frequency were Cordia alliodora, Persea americana, and Mangifera
indica.
In the present study, the structure of diameter classes presented a greater number of individuals within
the range 20.01 - 30 cm in diameter, which does not agree with the findings of (Zambrano, 2012) that
obtained the highest number of individuals in the interval of 0 - 5 cm in diameter.
Conclusions
We reviewed the article by (Moreno et al., 2013) that refers to traditional agroforestry systems in
Mexico, and with this reference the forest cover and its relationship with the agricultural systems of the
ten farms of the Corotú precinct, canton El Empalme, through a characterization four types of
agroforestry systems were defined which are: Trees in plots or dispersed in perennial crops (SAF1),
family orchard (SAF2), crops in alleys (SAF3) and trees in line (SAF4).
A total of 504 individuals dispersed in 35 associated species in 19 families and 33 genera were recorded
in combination with agricultural systems in the four types of agroforestry systems.
In the types of agroforestry systems found in the study area with the highest abundance of individuals
was for SAF1 with 335, followed by SAF2 with 133 and the least abundant SAF3 with 13 and SAF4
with 23 individuals, this differs because they are agricultural crops associated with trees, where the
shade factor affects the production of agricultural species, as shown in SAF3 and SAF4.
The species with the highest abundance, frequency, dominance within the agroforestry systems in the
Corotú enclosure were: Cordia alliodora and Persea americana, Triplaris cumingiana and the species
that were less abundant: Ceiba pentandra, Raphia taedigera, Pouteria caimito, Tabebuia guayacan,
Artocarpus altilis.
More species predominated in the class (40.01-50.0) cm. The most ecologically important species
exposed by the analysis of the Value and Importance Index "IVI" was Ceiba pentandra with 77.57%
respectively. In the diameter classes of the agroforestry systems the most dominant was SAF1 followed
by SAF2 and SAF4, which presented more individuals in the range of (20.01-30.0) cm. While in SAF3
> 50.01 cm.
Nivela, Cabrera, Salvatierra 2022
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