ABSTRACT
Introducción: Las selvas albergan más de la mitad de las especies del planeta, a pesar de la biodiversidad que poseen son los ambientes más amenazados, principalmente por actividades antrópicas, y su complejidad con relación a la altitud alberga vacíos de información a pesar de los valores que representa. Objetivo: Describir la estructura y diversidad de árboles en un gradiente altitudinal. Métodos: En cinco estratos altitudinales (EA) se establecieron 21 unidades de muestreo (UM) de 20 x 50 m: seis en el EA1, cinco en EA2, cuatro en EA3, tres en EA4 y 5. La estructura se caracterizó mediante las categorías diamétricas y de altura, y de los índices de valor de importancia (IVI) y forestal (IVF). La diversidad se analizó con los índices de Shannon-Wiener (H´) y Simpson (S), mientras la semejanza florística con el coeficiente de Sørensen (IS). Resultados: Se registraron 209 especies, ocho registradas en la Norma Oficial Mexicana-059-Secretaría de Medio Ambiente y Recursos Naturales-2010 (NOM-059-SEMARNAT-2019). Las especies con los mayores IVI e IVF fueron: Haematoxylum campechianum y Manilkara zapota en EA1; Rinorea guatemalensis y Pouteria reticulata en EA2; M. zapota y Brosimum alicastrum en EA3; Guatteria anomala y Pseudolmedia spuria en EA4; y Terminalia amazonia y Pouteria durlandii en EA5. En los cinco EA se identificaron tres rangos de altura y seis de diámetro, el mayor número de individuos se encontró en la primera categoria diamétrica. La diversidad de las especies fue menor a mayor altitud. En los EA 2 y 3 se presentó la mayor semejanza (IS = 58.7 %). Conclusión: La estructura y diversidad de las especies arbóreas, presentan mayores cambios en intervalos altitudinales más amplios, relacionados con la necesidad ambiental de cada especie.
Introduction: The forests are home to more than half of the planet's species, despite of their biodiversity, they are the ecosystems most threatened mainly by anthropic activities, but their complexity in relation to altitude has information gaps despite of the values it represents. Objective: Describe the structure and diversity of trees on an altitudinal gradient. Methods: In five altitudinal strata (EA) 21 sampling plots (UM) of 20 x 50 m were established: six in EA1, five in EA2, four in EA3, three in EA4 and 5. The structure was characterized by the categories diametric and height, and the importance value indexes (IVI) and forestry (IVF). Diversity was analyzed with the Shannon-Wiener (H´) and Simpson (S) indices, while the floristic similarity with the Sørensen coefficient (IS). Results: It was registered 209 tree species, eight are listed in the Official Mexican Standard-059-Secretariat of the Environment and Natural Resources-2010 (NOM-059-SEMARNAT-2019) as vulnerable species. The species with the highest IVI and IVF were Haematoxylum campechianum and Manilkara zapota in EA1; Rinorea guatemalensis and Pouteria reticulata in EA2; M. zapota and Brosimum alicastrum at EA3; Guatteria anomala and Pseudolmedia spuria in EA4; and Terminalia amazonia and Pouteria durlandii at EA5. In the five EAs, three ranges of height and six of diameter were identified, the largest number of individuals was found in the first diametric range. Species diversity was lower at higher altitudes. In EA 2 and 3 the greatest similarity was presented (IS= 58.7 %). Conclusion: The structure and diversity of the tree species present greater changes in wider altitude ranges, related to the environmental need of each species.
Subject(s)
Trees/anatomy & histology , Biodiversity , MexicoABSTRACT
Introduction: Islands are essential for world biodiversity. Isla del Coco National Park is an oceanic island in which a tropical rain forest grows; however, its ecology and the effect of introduced species are poorly understood. Objective: To evaluate the mortality, recruitment, regeneration, and growth of forest canopy species. Methods: We measured 15 permanent sampling plots (PSP), nine in the Premontane Pluvial Rainforest (PPR), and six in the Cloud Forest (CF); trees with DBH > 5 cm (diameter at breast height) were measured. The sampling regeneration was done within every PSP, along two transects of 1 X 50 m. Data analyses were performed using data obtained in 2006 and 2012 as baseline. Results: In the period 2012-2017, the annual mortality rate in the PPR was 5.75 % and for CF 6.31 %. The yearly recruitment rate in the PPR was 5.38 %, and 5.90 % for CF. For the PPR the total registered regeneration was 5 656 individuals and 8 700 for the CF. Sacoglottis holdridgei reported the highest mortality and the lowest values of recruitment and regeneration. Forest structure fits the inverted J model for most of the tropical forests. Sacoglottis holdridgei define the forest population structure above DBH > 20 cm. But, diameters under 20 cm are strongly influenced byH. succosa , because it reported the highest abundance of regeneration and recruitment. The annual average increase in diameter between forest was statically different (p = 0.0414; N = 15), 0.36 cm/year in the PPR, and 0.33 cm/year the in CF. Conclusions: The PPR and CF differ in the patterns of mortality, recruitment, and regeneration, confirming the uniqueness of these ecosystems. More successful regeneration ofH. succosawill lead to changes in structure and composition of forests, mainly PPR. The changes in forest structure will have a strong impact on epiphytic flora, microclimate conditions, and bird nesting such asGygis alba(White Tern) due to the loss of mature trees ofSacoglottis. The low regeneration ofS. holdridgeiis associated with the presence of introduced herbivores,their management is needed for restoring the forest.
Introducción: Las islas son esenciales para la biodiversidad mundial. El Parque Nacional Isla del Coco es una isla oceánica cubierta de bosques lluviosos tropicales; sin embargo, su ecología y el efecto de las especies introducidas son poco conocidos. Objetivo: Evaluar la mortalidad, el reclutamiento, la regeneración y el crecimiento de las especies arbóreas. Métodos: Se midieron 15 parcelas permanentes de muestreo (PPM), nueve en el bosque pluvial premontano (BPP) y seis en el bosque nuboso (BN); Se midieron árboles con DAP > 5 cm. El muestreo regeneración se realizó dentro de cada PPM, mediante dos transectos de 1 x 50 m. Los datos se analizaron tomando como línea base las mediciones del 2006, 2012 y 2017. Resultados: En el período 2012-2017, la tasa de mortalidad anual en el BPP fue de 5,75 % y para el BN de 6,31 %. La tasa de reclutamiento anual en el BPP fue de 5.38 % y 5.90 % para BN. Para el BPP, la regeneración total registrada fue de 5 656 individuos y 8 700 para el BN. Sacoglottis holdridgeituvo la mortalidad más alta y los valores más bajos de reclutamiento y regeneración. La estructura del bosque se ajusta al modelo J invertido para la mayoría de los bosques tropicales.Sacoglottis holdridgeidefine la estructura del bosque sobre diámetros > 20 cm. Pero, en diámetros < 20 cm está fuertemente influenciado porH. succosa , especie que reportó la mayor abundancia de regeneración y reclutamiento. El aumento promedio anual del diámetro entre bosques fue estadísticamente diferente (p = 0.0414; N = 15), 0.36 cm/año en el PPR y 0.33 cm/año en el CF. Conclusiones: El BPP y el BN difieren en los patrones de mortalidad, reclutamiento y regeneración, lo que confirma la singularidad de estos ecosistemas. Una regeneración más exitosa deH. Succosa provocará cambios en la estructura y composición de los bosques, principalmente BPP. Los cambios en la estructura del bosque tendrán un fuerte impacto en la flora epífita, las condiciones de microclima y la anidación de aves como Gygis alba(Palomita del Espíritu Santo) debido a la pérdida de árboles maduros de Sacoglottis . La baja regeneración deS. holdridgeiestá asociada con la presencia de herbívoros introducidos, para restaurar el bosque es necesario su manejo.
ABSTRACT
Tree plantations used for carbon sequestration or forest restoration often support diverse plant communities. However, it is unknown how rates of successional change in tree plantations compare to secondary forests. In this study, we compared the successional trajectory of tree plantations to that of secondary forests that were between 8 and 23 years old. Censuses of woody plants (≥ 2 cm dbh [diameter at breast height]) in seven tree plantation plots and seven secondary forest plots (30 × 30 m) were conducted over three years (May 2013-July 2016) in a lowland tropical forest. Secondary forests were naturally regenerating from abandoned cattle pastures. Tree plantations were monocultures of two different native species (Vochysia guatemalensis and Hieronyma alchorneoides), planted for carbon sequestration. We measured the change in stem density, basal area, species density, rarefied species richness, and relative abundance of different growth forms and regeneration guilds. We found that differences in stem density and basal area between these two forest types were declining. Nevertheless, we did not find evidence for differences between forest types in the rate of accumulation of species richness when accounting for sample size. On the other hand, even though the successional trajectory in tree plantations was very similar to secondary forests, there were differences between forest types in species composition. The rate of change in relative abundance of different growth forms and regeneration guilds was similar in both forest types. Overall, our results suggest that structural - but not compositional differences - between tree plantations and secondary forests are converging during the second decade of succession.
Las plantaciones forestales usadas para el secuestro de carbono o restauración forestal pueden sostener comunidades de plantas de alta diversidad. Sin embargo, no se sabe si las tasas de cambio sucesionales de plantaciones forestales son comparables con las de bosques secundarios. En este estudio, examinamos las trayectorias sucesionales en plantaciones forestales y bosques secundarios que tenían entren 8 y 23 años de edad. Realizamos inventarios de plantas leñosas (≥ 2 cm dap) en siete parcelas de plantaciones forestales y siete parcelas de bosques secundarios durante un periodo tres años (mayo 2013 - julio 2016) en un bosque tropical de tierras bajas. Estos últimos se regeneraron naturalmente en potreros abandonados, mientras que las plantaciones forestales fueron monocultivos de dos especies nativas (Vochysia guatemalensis y Hieronyma alchorneoides), sembradas para el secuestro de carbono. Medimos el cambio en densidad de tallos, área basal, densidad de especies, riqueza de especies y abundancia relativa de diferentes grupos funcionales. Encontramos que las diferencias en densidad de tallos y área basal, entre los dos tipos de bosques, estaban disminuyendo. No obstante, no hubo evidencia de diferencias entre los tipos de bosques en relación con la acumulación de riqueza de especies cuando se consideró el tamaño de la muestra, aunque había diferencias en la composición de especies, entre los dos tipos de bosque. Asimismo, en ambas zonas, la trayectoria sucesional en plantaciones forestales se parecía mucho. Por otro lado, la tasa de cambio en la abundancia relativa de grupos funcionales fue similar en ambos tipos de bosque. Por lo tanto, nuestros resultados sugieren que la diferencia en la composición de especies entre los tipos de bosque no disminuyó durante la segunda década de sucesión.
ABSTRACT
Resumen Dioon holmgrenii esta catalogada en peligro de extinción y es endémica del sur de Oaxaca, México. A pesar de la situación de esta especie, no existe información específica sobre aspectos ecológicos para cada población. Esto dificulta la autorización de planes de manejo para su conservación. El objetivo de este trabajo fue determinar los atributos dendrométricos, la estructura poblacional y la diversidad de estadios en diez poblaciones de D. holmgrenii localizadas en la Sierra Madre del Sur de Oaxaca. Cuatro unidades de muestreo (UM) de 25 x 50 m cada una (1 250 m2) se establecieron por población, 40 UM en total (50 000 m2). La densidad de plantas, el diámetro basal (DB), área basal (AB), altura de tallo (AT), diámetro de copa (DC), área de copa (AC) y número de hojas (NH) de los individuos se evaluó de enero a mayo 2013. Con estos datos se determinó la estructura poblacional, índice de dominancia estructural (IDE), heterogeneidad (H´), uniformidad (E) y semejanza (ISct) de estadios. La densidad en las poblaciones varió de 148 a 954 plantas ha-1. El área basal total fluctuó de 1.3 a 17.6 m2 ha-1 y área de copa total osciló de 78.3 a 1 136.3 m2 ha-1. Los atributos dendrométricos de los individuos (DB = 7.7 a 13.4 cm, AB = 0.010 a 0.023 m2, AT = 0.20 a 0.47 m, DC = 0.49 a 1.09 m, AC = 0.55 a 1.55 m2 y NH = 7.06 a 14.90) fueron diferentes entre las poblaciones (p ˂ 0.05). Adulto 1 y adulto 2 tuvieron mayor IDE (0.01 a 5.63) en todas las poblaciones. La estructura poblacional más común fue aquella donde juvenil 1 y juvenil 2 tuvieron las proporciones más bajas de individuos, mientras que adulto 1 tuvo la más alta. La heterogeneidad (H´= 1.05 a 1.71) y uniformidad (E = 0.57 a 0.88) de estadios fueron significativamente diferentes entre las poblaciones (p˂0.05), con al menos cuatro estadios (3.91 = 48.9x8/100) diferentes entre ellas para la mitad de las comparaciones (22 de 45) de semejanza (ISct < 0.68). La diversidad alfa de estadios fue alta en poblaciones donde no se dañaron las plantas, en contraste a la diversidad beta que fue baja entre poblaciones con presencia de actividad humana. Estadios con alto vigor reproductivo (adulto 1 y adulto 2) presentaron una mayor dominancia estructural en todas las poblaciones. Estos resultados pueden ayudar a la conservación in-situ de D. holmgrenii y se recomienda sean considerados en la elaboración y aplicación de planes de manejo de sus poblaciones.
Abstract Dioon holmgrenii is an endangered species and found in Southern Oaxaca, Mexico. Notwithstanding the extintion condition of this species, there is no relevant information on the ecological aspects of its populations, and this situation complicates the approval of management plans for its conservation. Our aim was to study D. holmgrenii forest characteristics, population structure and life-stages diversity in ten populations located in Sierra Madre del Sur, Oaxaca. For this, four sampling units (SU) measuring 25 x 50 m each (1 250 m2) were established per population, 40 SU in total (50 000 m2). Basal diameter (BD), basal area (BA), stem height (AT), crown diameter (DC), crown area (AC), and number of leaves (NH), were measured for each individual, from January to May 2013. Additionally, plant density, population structure, structural dominance index (IDE), heterogeneity (H'), evenness (E) and similarity (ISct) of life-stages (seedling, juvenile 1, juvenile 2, pre-reproductive, adult 1, adult 2, adult 3, and adult 4) were assessed. Plant density ranged from 148 to 954 individuals ha-1. Total basal area ranged from 1.3 to 17.6 m2.ha-1, and total crown area varied from 78.3 to 1 136.3 m2.ha-1. Forest traits of each individual (DB= 7.7 to 13.4 cm, AB= 0.010 to 0.023 m2, AT= 0.20 to 0.47 m, DC= 0.49 to 1.09 m, AC= 0.55 to 1.55 m2 and NH= 7.06 to 14.90) were different (p˂0.05) among populations. The highest values of IDE (0.01 to 5.63) were found in adult 1 and adult 2 in all populations. The most common population structure was found in those populations with the lowest proportions in juvenile 1 and juvenile 2, and the highest proportion in adult 1. Heterogeneity (H'= 1.05 to 1.71) and uniformity (E= 0.57 to 0.88) of life-stages were significantly different among populations (p˂0.05), and at least four life-stages (3.91= 48.9x8/100) were different among populations for half of the comparisons (22 of 45) of similarity (ISct < 0.68). Alfa diversity of life-stages was high in populations without plant damage, while beta diversity was low in those populations with human presence. Life-stages with the highest reproductive vigour (adult 1, adult 2) showed the highest structural dominance in all populations. These results may support the design and operation of management plans of D. holmgrenii populations, to enhance its protection in the area.
ABSTRACT
Soil and forest structure in the Colombian Amazon. Forests structural differences could result of environmental variations at different scales. Because soils are an important component of plant’s environment, it is possible that edaphic and structural variables are associated and that, in consequence, spatial autocorrelation occurs. This paper aims to answer two questions: (1) are structural and edaphic variables associated at local scale in a terra firme forest of Colombian Amazonia? and (2) are these variables regionalized at the scale of work? To answer these questions we analyzed the data of a 6ha plot established in a terra firme forest of the Amacayacu National Park. Structural variables included basal area and density of large trees (diameter≥10cm) (Gdos and Ndos), basal area and density of understory individuals (diameter<10cm) (Gsot and Nsot) and number of species of large trees (sp). Edaphic variables included were pH, organic matter, P, Mg, Ca, K, Al, sand, silt and clay. Structural and edaphic variables were reduced through a principal component analysis (PCA); then, the association between edaphic and structural components from PCA was evaluated by multiple regressions. The existence of regionalization of these variables was studied through isotropic variograms, and autocorrelated variables were spatially mapped. PCA found two significant components for structure, corresponding to the structure of large trees (G, Gdos, Ndos and sp) and of small trees (N, Nsot and Gsot), which explained 43.9% and 36.2% of total variance, respectively. Four components were identified for edaphic variables, which globally explained 81.9% of total variance and basically represent drainage and soil fertility. Regression analyses were significant (p<0.05) and showed that the structure of both large and small trees is associated with greater sand contents and low soil fertility, though they explained a low proportion of total variability (R² was 4.9% and 16.5% for the structure of large trees and small tress, respectively). variables with spatial autocorrelation were the structure of small trees, Al, silt, and sand. Among them, Nsot and sand content showed similar patterns of spatial distribution inside the plot. Rev. Biol. Trop. 59 (3): 1307-1322. Epub 2011 September 01.
Las diferencias estructurales del bosque pueden ser el producto de variaciones ambientales a diferentes escalas, entre ellas los suelos. Para evaluar tal asociación, se usaron los datos de estructura del bosque y de suelos de una parcela de 6ha establecida en un bosque de tierra firme de la Amazonía colombiana. Las variables edáficas y estructurales se redujeron con un análisis de componentes principales (ACP) y un análisis de regresión múltiple verificó si existía asociación entre los componentes edáficos y estructurales del ACP. La regionalización de las variables de estudio se verificó con variogramas isotrópicos; además, se construyeron mapas de distribución espacial. El ACP de las variables estructurales identificó dos componentes: dosel y sotobosque, los cuales explicaron el 43.9 y 36.2% de la varianza total, respectivamente; para las variables edáficas los cuatro primeros componentes explicaron globalmente el 81.9% de la varianza total. Los análisis de regresión mostraron que tanto el dosel como el sotobosque se asocian con mayores contenidos de arena y baja fertilidad del suelo (p<0.05), pero explicaron una proporción baja de la variabilidad total (R²=4.9% para dosel y 16.5% para sotobosque). Las tres variables de la estructura del sotobosque, Al, limo y arena presentaron autocorrelación espacial.
Subject(s)
Soil/chemistry , Trees/classification , Colombia , Principal Component AnalysisABSTRACT
O domínio do Cerrado compreende uma área contínua nos estados centrais do Brasil e áreas disjuntas em outros estados, incluindo São Paulo. Essa vegetação ocupava originalmente 21 por cento do território brasileiro, restando atualmente apenas 21,6 por cento de sua extensão original. A área recoberta por essa vegetação em São Paulo cobria 14 por cento de sua área total e seus remanescentes recobrem menos de 1 por cento da ocorrência original dessa vegetação. Estudos recentes indicam que o valor da produtividade líquida no Cerrado Pé-de-Gigante (SP) constitui um pequeno dreno de carbono e indicou que a sazonalidade foi o fator determinante do valor observado. Os estudos dos fluxos de carbono em ecossistemas terrestres são raramente acompanhados de abordagens ecofisiológicas de modo a explorar a relação funcional das espécies que compõem o ecossistema e os valores líquidos obtidos para o mesmo. Assim, o objetivo deste trabalho foi caracterizar estruturalmente a vegetação presente na área de maior influência da torre de fluxo instalada no Cerrado Pé-de-Gigante, visando possibilitar estudos relacionados à quantificação em longo prazo da dinâmica dos fluxos de água, energia e CO2 na vegetação de Cerrado. Para isso foram levantadas 20 parcelas (10 x 10 m) em 0,2 ha de Cerrado, e amostraram-se todas as plantas com perímetro ao nível do solo >6 cm (exceto lianas e árvores mortas). A distribuição das classes de diâmetro e estrutura vertical, assim como os parâmetros fitossociológicos foram analisados. Encontramos 1451 indivíduos, distribuídos em 85 espécies, 52 gêneros e 31 famílias. A densidade absoluta e área basal foram de 7255 ind. ha-1 e de 7,9 m².ha-1, respectivamente. A família Leguminosae apresentou o maior número de espécies (13). O Índice de diversidade de Shannon (H') foi 3,27 nats.ind-1. A distribuição em classes de diâmetro mostrou uma curva de "J" invertido, estando a maioria dos indivíduos na primeira classe. Concluímos que a área deve ser classificada como Cerrado denso, devido principalmente à dominância pela espécie arbórea Anadenanthera falcata, cuja ocorrência no estado foi relatada apenas em locais com solos ricos em saturação de bases na região das Cuestas Basálticas, devido também à maior área basal dos indivíduos, comparando com outros fragmentos de Cerrado. Além da espécie citada, Myrcia lingua e Xylopia aromatica, apresentaram os maiores IVI (Valor de importância).
The Cerrado vegetation covers the Brazilian central areas (core area) which include extensive and continuous areas in the central States and some marginal areas in other States, including São Paulo, accounting originally for 21 percent of Brazilian territory. Nowadays, the remnants are 21,6 percent of its original coverage. About of 14 percent of the São Paulo State territory was originally covered with Cerrado vegetation, and today remnants account for less than 1 percent of the original distribution. Recent studies indicate that the net productivity in the Pé-de-Gigante Cerrado constitutes a small carbon sink, with seasonality playing a major role. The carbon flux studies in terrestrial ecosystems have rarely been accompanied by ecophysiological studies in order to explore the functional relationships among species, ecosystem and the values achieved. Therefore, our objectives were to characterize the vegetation structure in the meteorological and flux tower footprint. The flux tower allows studies related to long term measurements and dynamics of water, solar energy and CO2 fluxes in Cerrado vegetation. Plots (10 x 10 m) were established in 0.2 ha area of Cerrado and all vascular plants with stem perimeter at ground level >6 cm (except vines and dead individuals) were sampled. The distribution of diameter classes and vertical structure, as well as the phytosociological parameters were analyzed. We recorded 1,451 individuals, distributed in 85 species belonging to 31 different families. The absolute density and the basal area were 7,255 ind.ha-1 and 7.9 m².ha-1, respectively. Leguminosae showed the highest number of species (13). The Shannon's Index was 3.27. The distribution of diameter classes showed a curve in inverted "J", most of the individuals being in the initial classes. We concluded that the area must be classified as dense Cerrado, mainly due to Anadenanthera falcata dominance, which occurrence in São Paulo State was reported only in rich soil sites in Cuestas Basaltic regions and also due to major basal area of these individuals, comparing with other Cerrado vegetation sites. A. falcata, Myrcia lingua and Xylopia aromatica showed the highest IVI (Importance value index).
ABSTRACT
O objetivo do presente estudo foi o de comparar a acuracidade e a precisão das estimativas de área basal obtidas de processos, intensidades e métodos amostrais com valores obtidos pelo censo, numa floresta ecotonal de 120 hectares na região norte matogrossense, para oito grupos de espécies e para espécies individuais para árvores com DAP ≥ 30 centímetros. Aplicaram-se os processos: aleatório e o sistemático, com uma intensidade amostral de 5 e 10 por cento para 22 tamanhos e formas de parcelas variando de 400 m² a 10000 m². A área basal média por hectare foi de 11,08 m². As parcelas de 2500 m² (125 m x 20 m) apresentaram erros reais e de amostragem sempre inferiores a 10 por cento na estimativa de área basal para os grupos de todas as espécies e para as 15 de maiores valores de importância (VI). Para os demais grupos os erros aumentam na medida em que decresce a quantidade de árvores por hectare. Para as espécies, individualmente, os erros variaram de 28,7 por cento (Vochysia sp.) a 250,59 (Hymenaeae courbaril), respectivamente, para a mais e a menos freqüente, mostrando inviabilidade na aplicação de processos estimativos tradicionalmente empregados nos inventários florestais, notadamente para estimar parâmetros específicos de espécies raras (baixa freqüência por hectare).
The objective of this research was to compare the accuracy and the precision of estimates from basal area obtained by processes, intensities and methods of sampling with true values gotten from the census, in an ecotonal forest of 120 hectares in the northern region of Matogrosso, for eight groups of species and for individual tree species with dbh ≥ 30 centimeters. The applied processes were: random and the systematic, with a sampling intensity of 5 percent and 10 percent for 22 sizes and forms of plots ranging from 400 m to 10000 m². The average basal area per hectare was 11.08 m². The 2500 m² (125 m x 20 m) plots presented actual and sampling errors always inferior to 10 percent in estimating basal area for all species and for the 15 of greater importance values (VI). For the other groups the errors increase accordance to the decrease of tree density. For the species, individually, the errors varied from 28.7 percent (Vochysia sp.) to 250.59 percent (Courbaril hymenaeae), respectively, for the most and the least dense, thus showing the unfeasibility of applying traditional estimative processes to estimate specific parameters of species with low frequency by hectare (rare species).