102

ABANDONED PLANTATIONS OF guianensis Aubl. IN NATURAL FOREST IN THE BRAZILIAN AMAZON: METHODS FOR REVITALIZATION

Núcleo de Meio Ambiente Universidade Federal do Pará Rua Augusto Corrêa, 01, Guamá ABSTRACT: In the Tapajós National Forest, it is common Belém, Pará, Brasil https://periodicos.ufpa.br/index.php/agroecossistemas practice to extract latex from rubber trees, and there are two large abandoned rubber plantations named Terra Rica and Seringal do Ponte, located in this conservation area. The objective of this research was to evaluate the dendrometric and silvicultural characteristics of the rubber trees as a way of providing subsidies for their reactivation. The data used were obtained from two 100% forest inventories, carried out in 2013 and 2018, and from a sampling to investigate the relationship Karla Mayara Almada Gomes, of dendrometric, morphometric, and competition indices for Universidade Federal do Oeste do Pará [email protected] tree diameters at 1.30 m above the soil, using the Pearson correlation index. 2,965 rubber trees were inventoried in 2013 João Ricardo Vasconcellos Gama and 2,927 in 2018, presenting a density of 97.9 trees.ha-1 and Universidade Federal do Oeste do Pará 96.6 trees.ha-1, respectively. There was a difference between [email protected] the total height and stem height of the rubber trees between Dárlison Fernandes Carvalho de the inventories; in diameter, the rubber trees remained the Andrade same and, in general, there were no problems of health Instituto Chico Mendes de Conservação in the plantations. To maintain productivity in the current da Biodiversidade [email protected] settlement conditions, it is necessary to not surpass a maximum amount of 130 trees.ha-1. Degree of insolation is Álvaro Augusto Vieira Soares one of the factors that affects latex production and rubber Universidade Federal de Uberlândia trees in abandoned plantations are predominantly shaded, [email protected] suffer losses in panel quality and show high variability of the Thiago de Paula Protásio trees' diameters and heights. This suggests the need for Universidade Federal Rural da Amazônia thinning in the plantations in order to eliminate both trees that [email protected] are thinner and that grow less, thus to favor the growth of the remaining rubber trees and elevate the production.

Recebido em: 2019-10-04 KEYWORDS: Amazon, Conservation unit, Forest Avaliado em: 2020-07-09 management. Aceito em: 2020-07-15

PLANTIOS ABANDONADOS DE Hevea guianensis Aubl. NA FLORESTA NATURAL DA AMAZÔNIA BRASILEIRA: MÉTODOS PARA REVITALIZAÇÃO

RESUMO: Na Floresta Nacional do Tapajós é comum a prática da extração de látex de seringueira e existem dois grandes

Agroecossistemas, v. 11, n. 2, p. 102 – 126, 2019, ISSN online 2318-0188 http://dx.doi.org/10.18542/ragros.v11i2.8662

103 plantios abandonados, denominados Terra Rica e Seringal do Ponte, localizados nessa unidade de conservação. O objetivo desta pesquisa foi avaliar as características dendrométricas e silviculturais das seringueiras como forma de fornecer subsídios para sua reativação. Os dados utilizados foram obtidos em dois inventários florestais 100%, realizados em 2013 e 2018, e em uma amostragem para investigar a relação dos índices dendrométricos, morfométricos e de competição para diâmetros de árvores a 1,30 m acima do solo, utilizando o índice de correlação de Pearson. Foram inventariadas 2.965 seringueiras em 2013 e 2.927 em 2018, apresentando uma densidade de 97,9 árvores.ha-1 e 96,6 árvores.ha-1, respectivamente. Houve diferença entre a altura total e a altura do fuste das seringueiras entre os inventários; em diâmetro, os seringais permanecem iguais e, em geral, não houve problemas de fitossanidade nos plantios. Para manter a produtividade nas atuais condições do povoamento, é necessário não ultrapassar uma quantidade máxima de 130 árvores.ha-1. O grau de insolação é um dos fatores que afeta a produção de látex e as seringueiras em plantios abandonados são predominantemente sombreadas, sofrem perdas na qualidade do painel e mostram alta variabilidade dos diâmetros e alturas das árvores. Isso sugere a necessidade de desbaste nas plantações, a fim de eliminar tanto as árvores mais finas quanto as que crescem menos, favorecendo o crescimento das seringueiras restantes e elevando a produção.

PALAVRAS-CHAVE: Amazônia, Unidade de conservação, Manejo florestal.

PLANTAS ABANDONADAS DE Hevea guianensis Aubl. EN EL BOSQUE NATURAL DE LA AMAZONIA BRASILEÑA: MÉTODOS DE REVITALIZACIÓN

RESUMEN: En el Bosque Nacional Tapajós, la práctica de extraer látex de caucho es común y existen dos grandes plantaciones abandonadas, llamadas Terra Rica y Seringal do Ponte, ubicadas en esta unidad de conservación. El objetivo de esta investigación fue evaluar las características dendrométricas y silvícolas de los árboles de caucho como una forma de otorgar subsidios para su reactivación. Los datos utilizados se obtuvieron de dos inventarios 100% forestales, realizados en 2013 y 2018, y en una muestra para investigar la relación de índices dendrométricos, morfométricos y de competencia para diámetros de árboles a 1,30 m sobre el suelo, utilizando el índice Correlación de Pearson. Se inventariaron 2.965 árboles de caucho en 2013 y 2.927 en 2018, con una densidad de 97,9 árboles.ha-1 y 96,6 árboles.ha-1, respectivamente. Hubo una diferencia entre la altura total y la altura del tallo de los árboles de caucho entre los inventarios; de diámetro, las plantaciones de caucho permanecen iguales y, en general, no hubo problemas fitosanitarios en las plantaciones. Para mantener la productividad en las condiciones poblacionales actuales, es necesario no superar una cantidad máxima de 130 árboles.ha-1. El grado de insolación es uno de los factores que incide en la producción de látex y los árboles de caucho en las plantaciones abandonadas son predominantemente sombreadas, sufren pérdidas en la calidad del panel y muestran alta variabilidad en los diámetros y alturas de los árboles. Esto sugiere la necesidad de raleo en las plantaciones, con el fin de eliminar tanto los árboles más delgados como los que crecen menos, favoreciendo el crecimiento de los árboles de caucho remanentes y aumentando la producción.

PALABRAS CLAVES: Amazonia, Unidad de conservación, Manejo forestal.

Agroecossistemas, v. 11, n. 2, p. 102 – 126, 2019, ISSN online 2318-0188 http://dx.doi.org/10.18542/ragros.v11i2.8662

104

INTRODUCTION

The Brazilian forestry sector stands out in production, to the quality and productivity of the national economy, being 1.1% of the the trees, and these factors depend mainly National Gross Domestic Product (GDP) and on the management decisions of the rubber 6.1% of Industrial GDP (IBÁ, 2019), as well as trees (PURNAMASARI et al., 2002). a significant participation in the international The management of rubber plantations, in timber market. Exports in this industry have turn, should be planned based on the totaled around of US $ 206.4 billion (IPEA, evaluation of these variables in order to 2019), especially in the segment of planted obtain a characterization that subsidizes the trees, for which Brazil has the highest levels prescription of suitable silvicultural of productivity in the world. Another relevant treatments for two reasons: to reach the segment is that of products derived from production in line with the potential of the plant extractivism, which guarantees the area and guarantee a management with a subsistence of numerous families in the basis for sustainable development (SILVEIRA interior of the country, moves local markets, et al., 2015; MENDONÇA et al., 2017; SOUZA and supplies large shopping centers, mainly et al., 2017; DOURADO et al., 2018; in the Amazon (IBGE, 2016). MEENAKUMARI et al., 2018). These

Among the products with economic, evaluations are based on studies of historical, and cultural importance is latex dendrometric and morphometric extracted in the Brazilian Amazon for at least characteristics and on the relationships two centuries. This has mainly pertained to between them, generating important metrics the Muell-Arg, that can be used, for example, to define the belonging to the family , of optimum plant density (HESS, 2018). great natural occurrence in the region In the Tapajós National Forest, a common (SILVA, 2002). Rubber plantations represent practice among residents is the extraction of a both renewable resource, however, the latex from native rubber trees, planted in the assurance that the production of natural backyards or in areas destined for rubber will be viable and result in profit is agriculture. In this conservation unit (UC), subject, in addition to the costs involved in there are two large rubber plantations,

Agroecossistemas, v. 11, n. 2, p. 102 – 126, 2019, ISSN online 2318-0188 http://dx.doi.org/10.18542/ragros.v11i2.8662

105 surrounded for natural forest, called Terra the following scientific question arose: how to

Rica and Seringal of Ponte - remnants of the evaluate abandoned rubber tree plantations? residents who lived in areas of the Tapajós The hypotheses tested were: H0 = the National Forest. They are not occupied and evaluation through the relationship between were not compensated for their possessions the dendrometric, morphometric variables, in the 1970s - when the community began to the competition indices and the DBH is plant rubber trees. effective to characterize the structure of the

The management of the UC has granted rubber trees; H1 = the evaluation through the authorizations for locals to serve as extractive relationship between dendrometric, dwellers to bleed in the rubber plantations of morphometric variables, competition indices Terra Rica and Ponte, which consists of a and DBH is not effective to characterize the superficial cut in the bark of the rubber tree, in structure of the rubber trees. The objective of order to extract the latex. The activity is carried this work was to evaluate the following: i) out on a small scale and sporadically, without dendrometric and silvicultural characteristics continuous use of the rubber plantations. As of of rubber trees; ii) growth of rubber trees 2011, the Flona Tapajós Mixed Cooperative under abandoned planting conditions; iii) (Coomflona), an economic entity formed by morphometric indices and competition the residents who carry out the forest indices with the aim to establish the optimum management in the UC decided to support the density per hectare for the species. activity. This mediates the purchase and sale of the raw material and, thus, strengthens the MATERIAL AND METHODS extraction of latex, which is another working STUDY AREA alternative for local residents. The study area comprises the rubber tree This research results from an integrated plantation in Terra Rica and Ponte, effort among cooperative residents and containing 27.41 and 2.90 hectares of researchers that aims to provide subsidies for extension, respectively: 02º50'08.96''S and the management of Hevea in plantations, 54º58'29.37''W. The distance between the based on the experiences of the rubber plantations is approximately 1.5 km, both plantations in Tapajós National Forest. Thus, located in the Tapajós National Forest,

Agroecossistemas, v. 11, n. 2, p. 102 – 126, 2019, ISSN online 2318-0188 http://dx.doi.org/10.18542/ragros.v11i2.8662

106 municipality of Belterra in the western Pará 163 Highway, where there is a monitoring state. Access to these sites is through a dirt base of the UC approximately 10 km from the road, near the kilometer (km) 67 of the BR rubber plantations (Figure 1).

Figure 1. Map of the location of the rubber tree plantations in the Tapajós National Forest, Belterra, Pará.

Source: Elaborated by the author.

The climate of the region is of the Ami type, characterized as Yellow Distrophic Latosol, and according to the classification of Köppen, the vegetation is classified as Dense which presents an average annual temperature Ombrophylous Forest (IBAMA, 2004). of 25.5°C and average relative humidity of approximately 90% (ALVARES et al., 2013). The CHARACTERIZATION OF PLANTATIONS topography of the region varies from For the evaluation of dendrometric and undulating to slightly undulating, the soil is silvicultural characteristics, two inventories were

Agroecossistemas, v. 11, n. 2, p. 102 – 126, 2019, ISSN online 2318-0188 http://dx.doi.org/10.18542/ragros.v11i2.8662

107 carried out, one in 2013 and the other in 2018, trees with DBH (diameter measured at 1.30 m and during this time, there was no intervention above the soil) ≥ 5 cm were measured in the in the rubber plantations. Quantitative and inventories. qualitative characteristics (Table 1) of all rubber

Table 1. Data collected in the first complete inventory of the rubber plantations.

Variable Description Total number of Record the quantity and placement of aluminum plates in the trees. CAP Circumference measurement, in centimeters, at 1.30 m (DBH). Total height Height of the soil at the apex of the tree, in meters. Stem height Height of the ground at first bifurcation, in meters. Crown lighting Full illumination (1), Partial illumination (2), Shading (3) or Tree without crown (4). Panel condition Good condition (1), Average condition (2), or Poor condition (3).

The panel is the portion of the shaft used in impel the flow of latex during the bleeding the bleed and is classified as: in good condition (Figure 2B); and poor condition, when weed and when there is no knots or accumulation of rubber accumulation along the cutting area and rubber along the cutting area (Figure 2A); the occurrence of pests and diseases is average condition when it presents some nodes significant and limits the flow of latex, blocking and accumulation of rubber, but that does not or delaying bleeding (Figure 2C).

Figure 2. Representation of panel condition categories in Good condition (A), Average condition (B) or Poor condition (C).

Source: Elaborated by the author.

Agroecossistemas, v. 11, n. 2, p. 102 – 126, 2019, ISSN online 2318-0188 http://dx.doi.org/10.18542/ragros.v11i2.8662

108

The rubber trees were also classified described in Table 2. The occurrence of according to the shape of the crown, diseases and pests was also observed to according to Silva and Lopes (1984), evaluate the sanity of the rubber trees.

Table 2. Classification of crown shape, adapted from Silva and Lopes (1984).

Crown shape Description Normal full crown Tree showing the full and well distributed crown (1). Tree with full crown, but poorly distributed, due to natural factors such as, growth Irregular full crown towards areas with higher incidence of light (2) Incomplete crown Tree that lost part of the crown because of natural causes or exploitation (3). Regrowth Crown in process of regeneration, after severe damage as the pickling (4). Tree without crown, knocked down by other trees because of forest exploitation Without crown or natural causes. (5).

Botanical collection was carried out to inventory were selected, and the paired t-test identify the species present in the planting, was applied at 95% probability. according to traditional methods of exsicata The diametric structure was analyzed by mounting, pressing, and preservation for means of frequency histograms with class further botanical identification according to the intervals of 10 cm (GAMA et al., 2017). To methods of Ming (1996). Each material was compare the diametric distributions between the herborized with the aid of a press and five years, the chi-square test was applied, at a newspaper and taken to a greenhouse with a significance level of 0.05. The sociological temperature of 60°C for 72 hours to dry the position was used to describe the structure of the material. After identification, the samples were plantations, considering the stratification by total incorporated into the herbarium of the Federal height, based on the mean and the standard Rural University of Amazonia (Ufra), located in deviation of the total height of the trees, being:

Belém in the state of Pará under registry 3441. bottom stratum = Ht < (퐻̅– 1s) ; medium stratum To compare the quantitative variables = (퐻̅ – 1s) ≤ Ht < (퐻̅+ 1s); upper stratum = Ht  between the measurements, the rubber trees (퐻̅ + 1s), where 퐻̅= Average total height, Ht = registered in both the first and the second Total height, and s = standard deviation of the total height (SOUZA; SOARES, 2013).

Agroecossistemas, v. 11, n. 2, p. 102 – 126, 2019, ISSN online 2318-0188 http://dx.doi.org/10.18542/ragros.v11i2.8662

109

For the dendrometric characterization of stem height measured in meters with a the rubber trees, the arithmetic means of the TruPulse 360 hypsometer; CAP - obtained with diameters (푑̅), the mean square diameter (푞), the help of graduated scale, in millimeters, and the basal area per hectare (퐺), and the mean converted into DBH; crown diameter - total height (퐻̅) were calculated. obtained by the measurement of eight crown radiuses, using the TruPulse 360 hypsometer COMPETITION AND MORPHOMETRIC INDICES laser beam, in meters, taking the tree as a point To characterize the morphometric indices of origin and distancing to the extreme and the competition indices, 103 trees were projection point of the crown, according to the randomly sampled, covering the diametrical adapted methodology of Condé et al. (2013). amplitude of the planting (5.0 cm ≤ DBH The first radius was taken from the north <97.0 cm) that were identified as the primary cardinal point and the following measured in trees, according to the methodology by the sequence: northwest, west, southwest, Silveira et al. (2015). south, southeast, east and northeast, The sample size was determined based on determined with the aid of a compass. the variability of latex production, considering The crown length was determined by the the study population as a finite population, difference between total height and stem according to Soares and Paula-Neto (1997). height. The following morphometric Each primary sampled tree had the variables were presented in Figure 3 following measured variables: total height and (SILVEIRA et al., 2015; SILVA et al., 2017):

Figure 3. Representation of total height and stem height, crown length and crown diameter.

Source: Elaborated by the author.

Agroecossistemas, v. 11, n. 2, p. 102 – 126, 2019, ISSN online 2318-0188 http://dx.doi.org/10.18542/ragros.v11i2.8662

110

(a) Crown diameter: calculated at twice the arithmetic mean of the eight crown radiuses measured: 푛 ∑ 푅푐푖 (Eq. 1) 퐷푐 = 2푅푐̅̅̅̅ 푅푐̅̅̅̅ = 푖=1 푛

Where: 퐷푐 = crown diameter, in meters; 푅푐푖 and ̅푅푐̅̅̅ = crown radius and arithmetic mean of crown radius in meters, respectively.

The crown diameter refers to the distance outermost points of the tree crown (DURLO; between the projection lines of the DENARDI, 1998).

b) Crown projection area: calculated using the median crown radius: 푆푐 = 휋푅푐̅̅̅̅ (Eq. 2)

Where: 푆푐 = crown projection area, in m².

Crown projection area refers to the radiuses of the crown (DURLO; DENARDI, surface covered by the vertical projection of 1998). This index allows to know the space the tree crown, usually calculated from the occupied by the tree (SILVA et al., 2017). measurement of four to eight projection

c) Crown percentage: 퐶푐 (Eq. 3) 푃푐 = × 100 퐻푡

Where: 푃푐 = Crown percentage; 퐶푐 = crown length, in meters; 퐻푡 = total height of the tree, in meters.

The ratio of crown length to total tree stem with crown needed to maintain tree height determines the extension of the stem, vital health (SILVA et al., 2017). referring to crown, that is, the percentage of

Agroecossistemas, v. 11, n. 2, p. 102 – 126, 2019, ISSN online 2318-0188 http://dx.doi.org/10.18542/ragros.v11i2.8662

111

d) Formal crown:

퐷푐 (Eq. 4) 퐹푐 = 퐶푐 Where: 퐹푐 = formal crown, in meters.

The formal crown denotes the degree of 2017). In general, the lower the value of this flattening of the crowns, being characterized index suggests greater influence of the as slender crowns when presenting values neighboring trees on the lateral expansion of below 1 and as flattened crowns when they the crown of the sampled tree (CUNHA; present values above 1. A lower index results FINGER, 2013). in higher productivity of the tree (SILVA et al.,

e) Slenderness Degree: 퐻푡 (Eq. 5) 퐺퐸 = × 100 퐷퐴푃 Where: 퐺퐸 = Slenderness degree.

The slenderness degree indicates the increase in height of the trees indicates that instability against the wind, and a taller tree for each meter that grows in height, they makes it more susceptible (SILVA et al., 2017; grow more than one centimeter in DBH, CARMONA et al., 2018). The decrease in the becoming more stable and robust (DURLO, degree of slenderness, together with the 2001).

f) Coverage index: 퐷푐 (Eq. 6) 퐼퐴 = × 100 퐻푡 Where: 퐼퐴 = coverage index.

The coverage index is determined by the index indicates the need for space by the tree relation between crown diameter and total with the increase in total height, that is, for a tree height (DURLO; DENARDI, 1998). This same height, the tree that presents greater

Agroecossistemas, v. 11, n. 2, p. 102 – 126, 2019, ISSN online 2318-0188 http://dx.doi.org/10.18542/ragros.v11i2.8662

112 crown diameter will reach greater space

(WEDGE; FINGER, 2013).

g) Salience index: 퐷푐 (Eq. 7) 퐼푆 = × 100 퐷퐴푃 Where: 퐼푆 = Salience index.

The salience index determines the vigor Considering the average of the salience between trees of the same diameter and index and crown diameter as constant, the indicates the space required for growth as the optimum density per hectare was determined, tree grows in diameter. Moreover, the according to Silva et al. (2017): reduction of the index may suggest that the individual is under strong competition (CUNHA; FINGER, 2013).

퐼푆 ∗ 퐷퐴푃 (Eq. 8) 푁푂 = 퐷푐 Where: 푁푂 = optimal tree number per hectare.

Each sampled tree had distances measured trees closest to the primary trees and with a laser beam to neighboring and competing trees, consisted of neighboring competing trees, which had their total heights trees that had a larger circumference at 1.30 m and DBH measured, to quantify the above the soil when compared to the primary competition by calculating the competition tree. indices, dependent and independent of the The relationship between morphometric distance for each sampled tree (Table 3). variables and competition indices with DBH As a criterion for defining neighboring and was investigated. Pearson's correlation competing trees, the methodology of Santos coefficient (r) was used to investigate the et al. (2015), who studied neighboring rubber existence of a relationship between

Agroecossistemas, v. 11, n. 2, p. 102 – 126, 2019, ISSN online 2318-0188 http://dx.doi.org/10.18542/ragros.v11i2.8662

113 morphometric variables and competition indexes with the growth of rubber trees.

Table 3. Competition indices used in the determination of competition in abandoned rubber plantations in the Tapajós National Forest, Belterra, Pará. Adapted from Silveira et al. (2015).

Relation to Index Equation Source distance 푛푗

BAL (Bali) 퐵푎푙푖 = ∑ 퐺푗 Independent Davis (2001) 푗=푖 2 푑푖 Glover e Holl (GHi) 퐺퐻 = ⁄ Independent Husch et al. (2003) 푖 푑̅2 푛 푑 푗 ( 푗⁄ ) Hegyi (H ) 푑푖 Dependent Gadow and Hui (1999) i 퐻푖 = ∑ 푙푖푗 푗=1 푛푗 Ratio height / distance ℎ푗 푅퐻퐿푖 = ∑ ⁄ Dependent Husch et al. (2003) (RHLi) 푙푖푗 푗=1 n: number of competing trees; Gj: basal area of competing trees (m²); di: DBH of the primary sampled tree (cm); 푑̅: Mean DBH of neighboring trees (cm); dj: DAP of competing trees (cm); lij: distance between primary sampled tree i and competing tree j (m); hj: total height of competing trees (m); i: order number of the primary tree; j: order number of the competing tree.

RESULTS AND DISCUSSION a record that this variable correlates In 2013, 2,965 rubber trees were significantly with its morphometric inventoried and, in 2018, 2,927 were characteristics and is strongly influenced by recorded, indicating a density of 97.9 forest management (NAJI et al., 2012). The trees.ha-1 and 96.6 trees.ha-1, respectively. In evaluated rubber plantations are the second inventory, the death of 56 rubber unmanaged, and the density found is lower trees was recorded, and 44 recruitments than that observed by Gama et al. (2017), were registered. In addition, 26 trees which evaluated the density of randomly inventoried in 2013 and not located in 2018 planted rubber plantations in Jamaraquá, were categorized as not found. Belterra municipality, a river community Plantation density is a determinant factor closest to the Terra Rica and Seringal of of production for the Hevea . There is Ponte in the Tapajós National Forest. The

Agroecossistemas, v. 11, n. 2, p. 102 – 126, 2019, ISSN online 2318-0188 http://dx.doi.org/10.18542/ragros.v11i2.8662

114 authors recorded a density of 285.6, 307.6, estimate were lower than the first inventory. and 210.3 trees.ha-1 in Terra Firme areas in the This result is attributed to the occurrence of hills, in the backyard, and igapó, respectively. mortality and recruitments in plantations. In However, in the Jamaraquá community, addition to mortality and recruitments, it is plantations are older because the "rubber noteworthy that different inventory teams economy" in the region occurred within estimated the height variable and, therefore, economic cycles, and the Belterra region was an estimation error must be considered. extensively used, since the municipality was Regarding the stem height, there was an founded as a village with the primary average increase of approximately one meter objective of latex production to meet the between the inventories (Table 4). demands of the external market (SILVA et al., The heterogeneity among the trees, 2016). In addition, the Jamaraquá rubber indicated by the variability of the diameters plantations are active and bring together the and heights in the rubber plantations, oldest rubber tappers, and the production of showed that although they are cultivating latex is an important source of income for the rubber trees, the rubber trees of Terra Rica community. and Ponte present high variability, which is In 2018, the average total height of rubber characteristic of poorly formed or conducted trees was lower than in 2013, and the settlements according to Scolforo (2005). minimum and maximum values of this

Table 4. Descriptive statistics of DBH, total height, and stem height variables for in the Tapajós National Forest, Belterra, Pará.

DBH (cm) Total height (m) Stem height (m) Descriptive Measures 2013 2018 2013 2018 2013 2018 Arithmetic Mean 35.68 36.55 18.39 15.73* 5.96 6.86* Minimum 6.68 10.50 5.00 3.00 1.00 1.00 Maximum 89.13 96.77 36.00 29.00 25.00 20.00 Standard deviation 11.44 11.82 5.41 3.76 3.27 3.31 Coefficient of variation 0.32 0.32 0.29 0.24 0.55 0.48 Where: DBH is the diameter at 1.30 m above the soil; * represents a significant difference by paired t-test at 95% probability.

Agroecossistemas, v. 11, n. 2, p. 102 – 126, 2019, ISSN online 2318-0188 http://dx.doi.org/10.18542/ragros.v11i2.8662

115

As for the percentage of illumination of affects latex production, noting that co- the crowns, the greatest variation between dominated trees are the most productive the inventories of 2013 and 2018 occurred (GAMA et al., 2017). There is a negative between the shaded trees, which went from correlation between latex production and 23.3% to 19.5%, respectively. The percentage radiation, and although light is essential as a of partially illuminated rubber trees increased primary source of energy in photosynthesis from 75.8% to 79.3%. Fully illuminated trees and, therefore, in latex production, light or rose from 0.9% to 1.2%. It was observed that sun promotes transpiration and makes water the rubber trees are predominantly shaded. a limiting factor (CONFORTO et al., 2005). In

This result is relevant, considering that the addition to changes in lighting, rubber trees degree of insolation is one of the factors that suffered losses in panel quality (Figure 4).

Figure 4. Percentage of panel condition of the rubber trees inventoried in 2013 and 2018 in the Tapajós National Forest, Belterra, Pará.

96,53% 90,67% 2013 2018

4,70% 1,99% 1,48% 4,63%

Good condition Average condition Poor condition

Source: Elaborated by the author.

The loss in the panel condition quality "once bled, it always has to be bled. In active between 2013 and 2018 is a consequence of plantations, silvicultural activity and the abandonment of the plantations. The interventions prevent the presence of results indicate that although the panel is well pathogens, and adequate management of done, if one spends a lot of time without the plantations allows for good regeneration cutting regularly, the quality is gradually capacity of the panels, which favors the reduced. The rubber tappers themselves say

Agroecossistemas, v. 11, n. 2, p. 102 – 126, 2019, ISSN online 2318-0188 http://dx.doi.org/10.18542/ragros.v11i2.8662

116 continuity of production (GONÇALVES; Most of the problems investigated by

FONTES, 2009). studies on genetic improvement in rubber Regarding the shape of the crown, it was plantations are disease and pest control and observed that the majority (67.29%) of the some point to the defense mechanisms of rubber trees have a normal or irregular full the plant itself as one of the main control crown. Only 0.08% of the trees presented no methods (FURTADO et al., 2008). The Terra crown. Considering that the plantations are Rica and Ponte rubber plantations are abandoned, this result is positive, since trees located in the middle of the forest and whose crowns are well-formed usually show without interventions, and these higher growth than those with incomplete or characteristics created a favorable condition poorly distributed crowns (ZIMMERMANN et for the self-defense of rubber trees. This al. 2016; WEBER et al. 2018). resulted in good sanitation of the plantations, In general, there were no health problems due to the relationship between the in the plantations. Only 15 trees (0.51%) plantations and the forest, which could be presented signs of disease, whose diagnosis observed through the few structural changes indicated rotting and five trees that in the rubber plantations. presented plague symptoms. As for the The plantations presented a low number botanical identification, the occurrence of the of individuals in the lower diametric classes species Hevea guianensis Aubl. was verified. and a high frequency in the intermediate The evaluation of the plantation health classes, noting a marked reduction in the showed that although they are abandoned larger classes in both 2013 and 2018 (Figure and are maintenance free, the plantations 5). No significant difference was detected remain healthy, since less than 1% of the between diametric measurement structures rubber trees presented disease or pests. This (p = 0.0857, in the chi-square test with a result is extremely satisfactory, since disease significance level of 5%). resistance is a limiting factor for latex production (GONÇALVES et al., 2002).

Agroecossistemas, v. 11, n. 2, p. 102 – 126, 2019, ISSN online 2318-0188 http://dx.doi.org/10.18542/ragros.v11i2.8662

117

Figure 5. Diametric distribution of rubber trees in 2013 and 2018 for abandoned plantations in the

Tapajós National Forest.

Source: Elaborated by the author.

The diameter distribution of the rubber remained similar between the inventoried trees corroborated the results of Gama et al. years. Most trees were concentrated in the (2017) for rubber trees grown in Jamaraquá middle stratum in both the 2013 stratum and Araújo et al. (2018) for rubber plantations (medium stratum = 12.97

Agroecossistemas, v. 11, n. 2, p. 102 – 126, 2019, ISSN online 2318-0188 http://dx.doi.org/10.18542/ragros.v11i2.8662

118

Regarding the dendrometric variables providing results for silvicultural practices evaluated, an increase was observed in (SILVA et al., 2017). relation to the mean square diameter, which The relation between crown diameter and increased from 37.5 cm in 2013 to 38.4 cm in DBH is called the projection index, which 2018. A small variation was also observed in influences the free space around each tree in the basal area per hectare, which increased order to occupy space more efficiently and has from 10.8 m2.ha-1 to 11.0 m2.ha-1 in the rubber a ideal area for crown projection (ORELLANA; trees. In comparison to the dendrometric KOEHLER, 2008; SILVEIRA et al., 2015). The characterization performed by Siqueira et al. reduction of the salience index with the

(2017), the authors found similar or inferior increase in diameter was observed in the means sampling 928 rubber trees composed plantations, which according to Silva et al. of genetically improved clones, analyzing a (2017), indicates the need to perform thinning 10 hectares plantation of Hevea brasiliensis in the settlement. with 25 years of implantation that was The lack of significant diametric decrease located at the Central Experimental Center of demonstrated the need for silvicultural the Agronomic Institute in Campinas, São treatments so that the production activities in Paulo. the plantations can be continued. According to

The mean values of the morphometric Durlo and Denardi (1998), in areas with mixed variables are presented in Table 5. The data and unequal population characteristics such as shows the heterogeneity among the trees the rubber plantations under study, it is sampled, indicated by the variability of the possible to use the salience index to determine diameters and heights. The analysis of the space to be maintained around a tree and morphometric indices is a good indicator of optimize its growth without competition. This thinning and competition in plantations, variable can therefore be used as a thinning indicator.

Agroecossistemas, v. 11, n. 2, p. 102 – 126, 2019, ISSN online 2318-0188 http://dx.doi.org/10.18542/ragros.v11i2.8662

119

Table 5. Morphometric variables of the primary sampled trees in the abandoned rubber plantations in the Tapajós National Forest, Belterra, Pará.

DBH Category Counts Variable Average 10 20 30 40 50 60 70 ≥ 80 Nº of trees 1 13 22 22 28 10 5 2 - DBH (cm) 15.9 22.7 30.7 40.8 50.1 60.8 69.8 78.6 46.2 Total height (m) 10 14.2 14.3 18.2 18.3 21.2 22.0 21.0 17.4 Stem height (m) 8.9 10.8 5.4 6.0 4.7 6.1 5.5 6.3 6.7 Crown length (m) 1.0 3.2 4.6 7.4 7.1 8.7 11.0 8.0 6.4 Crown diameter (m) 13.5 9.4 11.0 11.1 12.2 13.2 12.9 13.9 12.2 Crown Projection Area (m²) 143.1 81.0 102.7 106.9 127.9 144.9 133.4 156.6 124.6 Crown percentage (%) 10.0 20.8 29.9 40.1 39.1 41.2 50.3 38.0 33.7 Formal Crown 13.5 5.5 3.8 1.7 2.0 2.3 1.2 1.8 4.0 Slenderness Degree 62.8 63.3 46.9 44.8 36.7 35 31.6 26.7 43.5 Coverage Index 1.4 0.7 0.8 0.6 0.7 0.6 0.6 0.7 0.8 Salience Index 84.8 41.8 36.5 27.3 24.7 21.7 18.5 17.7 34.1

The salience index found for the plantations consequently, lesser productivity of the rubber is considered high (mean = 34.13). In the trees when considering the general average studies carried out by Tonini and Arco-Verde found for the salience index, it is necessary to

(2005), andiroba (Carapa guianensis), maintain a maximum amount of 130 trees. ha-1 castanheira-do-Brasil (Bertholletia excelsa), ipê- to avoid competition by crown. roxo (Tabebuia avellanedae), and jatobá Regarding the crown percentage, the values (Hymenaea courbaril) were recorded, varying ranged from 10.00% to 37.95%, presenting a from 14.7 to 50.3, and indicated high general average of 33.66%, and this indicates competition at a value of 25 and higher for that the rubber trees in the studied plantations these four species native to the Amazon. with an average total height of 17.41 m have Considering the general average found for approximately 6.37 m in crown height. the salience index, the maximum optimum According to Silva et al. (2017), this percentage density of the plantations is 130 trees. ha-1, so refers to how much of the total height of the there is no crown competition. In order to rubber trees is intended for tree distribution, avoid possible increased losses and, vitality, and productivity, since the

Agroecossistemas, v. 11, n. 2, p. 102 – 126, 2019, ISSN online 2318-0188 http://dx.doi.org/10.18542/ragros.v11i2.8662

120 interdimensional relationships of the trees infer were found, probably knocked down by the the space necessary for their growth, wind. influencing the competition in the plantation The coverage index, determined by the (DURLO, 2001). relation between crown diameter and total tree The formal crown index expresses the height (SILVA et al., 2017), ranged from 0.61 to photosynthetic capacity, that is, the 1.35 among diametric classes. These results are productivity of the tree (WEDGE; FINGER, superior to those found by Carmona et al. 2013). In the rubber plantations, the average (2018) when evaluating the morphometric crown was 3.98, ranging from 1.23 to 13.50, variables of planted rubber trees for an with flattened crowns. This index consists of the agroforestry system in Monte Alegre, Pará relationship between crown diameter and state. crown height and serves as a criterion for the According to Finger (1992), tree growth is definition of thinning, indicating that lower influenced by genetic factors of the species, values result in higher productivity for the same which interact with environmental factors, with species and site (DURLO; DENARDI, 1998). soil characteristics, and also with biological Low values of slenderness indicate that trees factors such as competition. In the rubber are growing more in diameter than in height plantations, the absence of significant growth

(TONINI; ARCO-VERDE, 2005). In the rubber is also the result of competition, which was trees evaluated, this index ranged from 26.71 to confirmed by the distance-dependent indices.

62.83 among the diametric classes, Both the Hegyi index (퐻푖 = 0.27) and the demonstrating that in the highest classes of height-to-distance ratio (푅퐻퐿푖 = 3.41) of the DBH, trees grow more in diameter than height competing trees have demonstrated the and, in the lower classes, are the most unstable existence of competition, indicating that the trees that break in the wind. Thus, it can be primary sampled trees suffer great competition stated that Hevea guianensis is susceptible to from neighboring trees. The higher these the action of the wind, a diagnosis verified in values and the greater the proximity of the field when after a strong wind occurred in neighboring trees results in their greater the first semester of 2018, some fallen trees influence on the growth of the sampled tree.

Agroecossistemas, v. 11, n. 2, p. 102 – 126, 2019, ISSN online 2318-0188 http://dx.doi.org/10.18542/ragros.v11i2.8662

121

Regarding the competition indices for in explaining the competition conditions in the distance, the Glover and Hool index also rubber plantations under study. signaled the existence of competition in the The results of the Pearson correlation rubber plantations. A higher value suggests the analysis of the DBH with the morphometric primary tree has less competitors, that is, the variables and the competition indices for the less competition is suffered, as Silveira et al. plantations are presented in Table 6. The

(2015) found 퐺퐻푖 = 0.6 for Trichilia claussenii. results presented significant coefficients with a This value is lower than that found for Hevea degree of slenderness (r = -0.7045) for the guianensis in the present study (퐺퐻푖 = 1.40), DBH. The negative sign indicates that a higher thus inferring that the trees of this species are DBH will result in a lower degree of influenced by the growth of neighboring trees. slenderness. When evaluating a plantation of Ocotea porosa In general, none of the competition or implanted in 1967 in Paraná, Santos et al. (2015) morphometric indices showed a significantly confirmed that this value indicates a high strong correlation with the DBH of the rubber degree of competition, as its growth was trees, and the degree of slenderness influenced by the neighboring trees with a presented the highest index with a moderate value of 1.29 for the Glover & Hool index, which negative correlation. The more unstable is inferior to the one found for Hevea trees, that is to say, with a greater degree of guianensis in the plantations. slenderness, are concentrated in the smaller

Only the BAL index (퐵푎푙푖 = 0.24) indicated diametric classes. This suggests the need for a low influence of the competition in the thinning in the plantations in order to plantations, since a higher BAL index suggests eliminate both trees that are thinner and that more competition for the tree (SILVEIRA et al., grow less, thus to favor the growth of the 2015). However, this index was not very efficient remaining rubber trees and elevate the production.

Agroecossistemas, v. 11, n. 2, p. 102 – 126, 2019, ISSN online 2318-0188 http://dx.doi.org/10.18542/ragros.v11i2.8662

122

Table 6. Pearson correlation coefficients between morphometric variables and competition indices with DBH for Hevea guianensis Aubl. in abandoned rubber plantations in the Tapajós National Forest, Belterra, Pará.

Variable r Crown height (m) 0.5286* Crown diameter (m) 0.2115* Crown projection area (m²) 0.1903ns Crown percentage (%) 0.3944* Formal Crown -0.4215* Slenderness Degree -0.7045* Coverage Index -0.2676* Salience Index -0.6142*

퐵푎푙푖 0.3896*

퐺퐻푖 0.6853*

퐻푖 -0.5710* ns 푅퐻퐿푖 0.1891

Where: r: Pearson's linear correlation coefficient; 퐵푎푙푖: BAL index; 퐺퐻푖: Glover and Holl index; 퐻푖: Hegyi index; 푅퐻퐿푖: relationship between height of competing trees and distance between primary sample tree i and competing tree j; i: order number of the primary tree; j: order number of the competing tree; ns: value of r with non-significant probability; *: significant r values at 5% probability.

CONCLUSION eliminate both trees that are thinner and that Evaluation of the relationship between the grow less, thus to favor the growth of the dendrometric variables, morphometric remaining rubber trees and elevate the variables, the competition indices, as well as production. the DBH, was effective to characterize the structure of the rubber trees. ACKNOWLEDGMENTS Degree of insolation is one of the factors We thank the institutions that contributed to that affects latex production and rubber trees the development of this research: National in abandoned plantations are predominantly Council for Scientific and Technological shaded, suffer losses in panel quality and Development (CNPq), Coordination for the show high variability of the trees' diameters Improvement of Higher Education Personnel and heights. This suggests the need for (Capes), Flona Tapajós Mixed Cooperative thinning in the plantations in order to (Coomflona), Chico Mendes Institute for

Agroecossistemas, v. 11, n. 2, p. 102 – 126, 2019, ISSN online 2318-0188 http://dx.doi.org/10.18542/ragros.v11i2.8662

123

Biodiversity Conservation (ICMBio), Federal CUNHA, T. A.; FINGER, C. A. G. Competição assimétrica e o incremento diamétrico de Rural University of Amazonia (UFRA) and Forest árvores individuais de Cedrela odorata L. na Ecosystems Management Laboratory of the Amazônia ocidental. Acta Amazônica, v. 43, n. 1, p. 9-18, 2013. Federal University of the West of Pará (Ufopa). DAVIS, L. S.; JOHNSON, K. M.; BETTINGER, P.; HOWARD, T. Forest Management: to Sustain REFERENCES Ecological, Economic and Social Values. New ARAÚJO, E. R.; WIMMER, P.; NASCIMENTO York: Macgrall-Hill, 2001. 816 p. IRMÃO, M.; FALCÃO, N. P. S.; ALFAIA, S. S. DOURADO, C. L.; MORAES, M. A.; ALVES, P. Ecologia e produtividade de seringais em F.; MAKUBOTA, T. Y. K.; SILVA, J. R.; sistemas agroflorestais próximos a cursos MOREIRA, J. P.; SILVA, A. A.; CAMBUIM, J.; d’água no médio Rio Amazonas. In: SOUZA, GONÇALVES, P. S.; MORAES, M. L. T. L. A.G.; FILHO, D. F. S.; BENAVENTE, C. A. T.; Selection strategies for growth characters NODA, H. (Org.). Ciência e tecnologia and rubber yield in two populations of aplicada aos agroecossistemas da Amazônia rubber trees in Brazil. Industrial Crops and Central. Manaus: Editora do Instituto Products, v. 118, p. 118-124, 2018. Nacional de Pesquisas da Amazônia, 2018, p. 1-283. DURLO; M. A.; DENARDI, L. Morfometria de Cabralea canjerana em mata secundária CARMONA, I. N.; AQUINO, M. G. C.; ROCHA, nativa do Rio Grande do Sul. Ciência D. I. S.; SILVA, J. J. N.; FICAGNA, A. G.; Florestal, v.8, n.1, p. 55-66, 1998. BALONEQUE, G. D.; OTAKE, M. Y. F. PAULETTO, D. Variáveis morfométricas de DURLO, M.A. Relações morfométricas para três espécies florestais em sistema Cabralea canjerana (Well.) Mart. Ciência agroflorestal. Agroecossistemas, v. 10, n. 1, p. Florestal, v. 11, n. 1, p. 141-150, 2001. 131-144, 2018. FINGER, C. A. G. Fundamentos de Biometria CONDÉ, T. M.; LIMA, M. L. M.; LIMA NETO, E. Florestal. Santa Maria: UFSM/CEPEF/FATEC, M.; TONINI, H. Morfometria de quatro 1992, 269 p. espécies florestais em sistemas agroflorestais no munícipio de Porto Velho, Rondônia. FURTADO, E. L.; MENTEN, J. O. M.; PASSOS, Revista Agro@mbiente On-line, v. 7, n. 1, p. J. R. Intensidade do mal das folhas em 18-27, 2013. plantas jovens e adultas de seis clones de seringueira na região do Vale do Ribeira. CONFORTO, E. C.; CAVALCANTE, J. R.; Tropical Plant Pathology, v.33, n. 2, 2008. PESSOA, J. D. C.; MORENO, R. M. B.; MATTOSO, L. H. C. Variação sazonal das GADOW, K. V.; HUI, G. Modelling Forest trocas gasosas, turgescência relativa do Development. Dordrecht: Kluwer Academic tronco e produtividade em dois cultivares de Publishers, 1999. 213 p. seringueira em Votuporanga, SP, Brasil. Acta Botânica Brasilica, v.19, n. 4, p. 733-740, 2005. GAMA, J. R. V.; VIEIRA, D. S. SANTOS, S. B.; SANTOS, M. R. G. Potencial de produção dos

Agroecossistemas, v. 11, n. 2, p. 102 – 126, 2019, ISSN online 2318-0188 http://dx.doi.org/10.18542/ragros.v11i2.8662

124 seringais de Jamaraquá, estado do Pará. Plano de Manejo. Volume 1, Brasília, 2004. Advances in Forestry Science, v.4, n.1, p.77- 580 p. 82, 2017. IBGE – INSTITUTO BRASILEIRO DE GONÇALVES, P. D. S.; FONTES, J. R. A. GEOGRAFIA E ESTATÍSTICA. Produção da Domesticação e Melhoramento da Extração Vegetal e da Silvicultura. Rio de Seringueira. p.395-423. In: BORÉM, A., Janeiro, 2016. 54 p. LOPES, M. T. G. E CLEMENT, C. R. (Ed.). Domesticação e Melhoramento. Espécies IPEA – INSTITUTO DE PESQUISA Amazônicas. Viçosa: Universidade Federal de ECONÔMICA APLICADA. Exportações - Viçosa, 2009, p. 395‑423. setor: produção florestal. Disponível em: http://www.ipeadata.gov.br/Default.aspx. GONÇALVES, O. S.; MARTINS, A. L. M.; Acesso em: 30 mai. 2019. FURTADO, E. L.; SAMBUGARO, R.; OTTATI, E. L.; ORTOLANI, A. A.; JÚNIOR, G. G. JARDIM, F. C. S.; SERRÃO, D. R.; NEMER, T. C. Desempenho de clones de seringueira da Efeito de diferentes tamanhos de clareiras, série IAC 300 na região do planalto de São sobre o crescimento e a mortalidade de Paulo. Pesquisa Agropecuária Brasileira, v. espécies arbóreas, em Moju-PA. Acta 37, n. 2, p. 131-138, 2002. Amazonia, v. 37, n. 1, 37-48, 2007.

HESS, A. F.; LOIOLA, T. M.; MINATTI, LIMA, J. P. C.; LEÃO, J. R. A. Dinâmica de MYRCIA; ROSA, G. T.; SOUZA, I. A; COSTA, E. Crescimento e Distribuição Diamétrica de A.; SCHORR, L. P. B.; BORSOI, G. A.; STEPKA, Fragmentos de Florestas Nativa e Plantada T. F. Morphometric Relationships as na Amazônia Sul Ocidental. Floresta e Indicative of Silvicultural Interventions for Ambiente, v. 20, n. 1, p. 70-79, 2013. Brazilian Pine in Southern Brazil. Journal of MEENAKUMARI, T.; RAJESWARI Agricultural Science, v. 10, n. 7, p. 110-121, MEENATTOOR, J.; THIRUNAVOUKKARASU, 2018. M.; VINOD, K. K.; KRISHAN, B.; GIREESH, T.; HUSCH, B.; BEERS, T. W; KERSHAW, J. A. THOMAS, V.; MYDIN, K. K.; JACOB, J. Forest Mensuration. New Jersey: John Wiley Dynamics of long-term adaptive responses in & Sons Inc., 2003. 456 p. growth and rubber yield among Hevea brasiliensis genotypes introduced to a dry IBÁ – INDÚSTRIA BRASILEIRA DE ÁRVORES. sub-humid climate of Eastern India. Industrial Cenários Ibá: Estatísticas da Indústria Crops and Products, v. 119, p. 294-303, 2018. Brasileira de Árvores| 1º trimestre de 2019. Disponível em: https://iba.org/datafiles/e- MENDONÇA, g. c.; CHICHORRO, J. F.; mail-marketing/cenarios/cena-rios-57- MENDONÇA, A. R.; GUIMARÃES, L. A. O. P. 1otrim-2019-iba.pdf. Acesso em: 17 jul. 2019. Avaliação silvicultural de dez espécies nativas da Mata Atlântica. Ciência Florestal, v. 27, n. IBAMA – INSTITUTO BRASILEIRO DO MEIO 1, p. 277-290, 2017. AMBIENTE E DOS RECURSOS NATURAIS RENOVÁVEIS. Floresta Nacional do Tapajós: MING, L. C. Coleta de plantas medicinais. In: DI STASI, L.C. (Org.). Plantas medicinais: arte e ciência. São Paulo: UNESP, 1996. p. 47-68.

Agroecossistemas, v. 11, n. 2, p. 102 – 126, 2019, ISSN online 2318-0188 http://dx.doi.org/10.18542/ragros.v11i2.8662

125

NAJI, H. R.; SAHRI, M. H.; NOBUCHI, T.; comunidades da FLONA do Tapajós: bases BAKAR, E. S. Clonal and planting density empíricas para a discussão da racionalidade effects on some properties of rubber wood ambiental. Gaia Scientia, Edição Especial (Hevea Brasiliensis Muell. Arg. BioResources, Cultura, Sociedade & Ambiente, v. 10, n. 1, p. v. 7, n. 1, 189-202, 2012. 126-132, 2016.

ORELLANA, E.; KOEHLER, A. B. Relações SILVEIRA, B. D. FLORIANO, E. P.; NAKAJIMA, morfométricas de Ocotea odorifera (Vell.) N. Y.; HOSOKAWA, R. T.; ROSOT, N. C.; Rohwer. Revista Acadêmica Ciências Agrárias GRACIOLI, C. Relação da morfometria e e Ambientais, v. 6, n. 2, p. 229-237, 2008. competição com o crescimento de Trichilia claussenii em um fragmento de floresta PURNAMASARI, R.; CACHO, O.; SIMMONS, semidecidual, RS. Revista Floresta, PR, v. 45, P. Management strategies for Indonesian n. 2, p. 373-382, 2015. rubber production under yield and price uncertainty: a bioeconomic analysis. SIQUEIRA, G. M.; VIEIRA, S. R.; PIERRE, L. H.; Agroforestry Systems, v. 54, n. 2, p. 121-135, GREGO, C. R. Spatial variability of rubber tree 2002. dendrometrics characteristics and soil physical attributes. Journal of Geospatial SANTOS, A. T.; MATTOS, P. P.; BRAZ, E. M.; Modelling, v.2, n.2, p. 32-41, 2017. ROSOT, N. C. Determinação da época de desbaste pela análise dendrocronológica e SOARES, C. P. B.; PAULA NETO, F. morfométrica de Ocotea porosa (Nees & Determinação do tamanho da amostra em Mart.) Barroso em povoamento não um inventário volumétrico e de biomassa de manejado. Ciência Florestal, v. 25, n. 3, p. troncos. Revista Ceres, v. 44, n. 252, p. 142- 699-709, 2015. 151, 1997.

SCOLFORO, J. R. Biometria Florestal; Parte 1: SOUZA, A. L.; SOARES, C. P. B. Florestas modelos de regressão linear e não linear; Nativas: estrutura, dinâmica e manejo. Parte II: modelos para relação hipsométrica, Viçosa: Editora UFV, 2013. 322 p. volume, afilamento e peso de matéria seca. Lavras, ESAL/FAEPE, 2005. 352p. SOUZA, A. S.; SANTOS, J. X.; SOUZA, D. V. Modelagem da relação hipsométrica para SILVA, F. A.; FORTES, F. O.; RIVA, D.; um povoamento híbrido de eucalipto na SCHORR, L. P. B. Caracterização de índices Amazônia brasileira. BIOFIX Scientific Journal, morfométricos para Araucaria angustifolia v. 2, n. 1, p. 44-53, 2017. plantada na Região Norte do Rio Grande do Sul. Advances in Forestry Science, v.4, n.3, TONINI, H.; ARCO-VERDE, M. Morfologia da p.143-146, 2017. copa para avaliar o espaço vital de quatro espécies nativas da Amazônia. Pesquisa SILVA, J. A. Inventário de seringueiras nativas Agropecuária Brasileira, v. 40, n. 7, p. 633- numa área da Amazônia Ocidental. Floresta 638, 2005. e Ambiente, v. 9, n. 1, p. 110-118, 2002. WEBER, V. P.; FINGER, C. A. G.; COSTA, E. A.; SILVA, R. E.; SOUZA, R. R.; BONFIM, F. S. A ZIMMERMANN, A. P. L.; LONGHI, R. V. extração do látex e a coleta de sementes em Modelagem linear generalizada para

Agroecossistemas, v. 11, n. 2, p. 102 – 126, 2019, ISSN online 2318-0188 http://dx.doi.org/10.18542/ragros.v11i2.8662

126 descrever o incremento em área transversal ZIMMERMANN, A. P. L.; COSTA, E. A.; de árvores individuais de Imbuia. Floresta, v. SCHRODER, T.; FLEIG, F. D. Modelagem do 48, n. 1, p. 123-132, 2018. incremento diamétrico de Pinus taeda em função de variáveis da copa e índices de competição. Floresta, v. 46, p.115-122, 2016.

Agroecossistemas, v. 11, n. 2, p. 102 – 126, 2019, ISSN online 2318-0188 http://dx.doi.org/10.18542/ragros.v11i2.8662