Eucalyptus Grandis Clones Research Articles

Relações entre o espaçamento arbóreo e características do campo nativo em sistemas silvipastoris no bioma Pampa

ABSTRACT: The current study assessed the association of eucalyptus-tree spacing with forest growth and yield, as well as with the floristic composition, diversity and yield of natural grassland grown in silvopastoral systems in Pampa biome. Data were collected in six family cattle-ranching area in Bagé County (RS). The effect of two different genetic materials (seminal-origin Eucalyptus dunnii plant and one Eucalyptus grandis clone) on shading features of plants grown in 3 planting-spacing dimensions(625, 312 and 208 trees ha-1) was assessed, as well as their association with herbaceous extract (bare soil; green cover; forage dry matter; floristic composition; species richness; and grass, legumes and winter - and summer-growth species rates) and forestry (litter accumulation, diameter at breast height, total height and volume per hectare) variables. Planting carried out at the highest tree density (625 trees ha-1) has increased forest yield. However, it reduced green cover, herbaceous extract dry-matter yield and species richness, mainly in grasses and legumeswith greater forage potential. Conversely, it is possible combining forestry and animal yield to the preservation of native forage species at low tree densities (204 to 312 trees ha-1).

Eucalyptus camaldulensis ve Eucalyptus grandis türleri ile melezlerinin klon denemeleri: Beşinci yaş sonuçları

Bu çalışmada, Eucalyptus camaldulensis Dehn.ve Eucalyptus grandis W.Hill ex Maiden ile bunlara ait melezler; farklı yetişme ortamlarında boy, çap, hacim ve yaşama oranı açısından klonal olarak mukayese edilmiştir. Dört farklı yerde, rastlantı blokları deneme desenine göre tesis edilen deneme alanlarında klonlar, 5 blokta toplam 25 fidan ile temsil edilmiştir. Fidanlar, beş ağaçlı sıra parseli şeklinde 3,25x3,25m aralık mesafede dikilmiştir. Varyans analizi sonuçlarına göre, gelişim ve yaşama oranı açısından bütün deneme alanlarında klonlar arasında istatistiksel olarak önemli bir fark oluşmuştur. Hacim gelişimi ve yaşama oranının birlikte değerlendirilmesi sonucunda; Karabucak ve Ceyhan koşullarında G96 klonu, Kırıkhan koşullarında ise C298 klonu en yüksek değerlere sahip olmuştur. Öte yandan, daha az sayıda yaşayan klona sahip olan Kırıkhan hariç diğer üç deneme alanları arasında gelişim ve yaşama oranı açısından istatistiksel olarak fark çıkmıştır. Bu değişkenler açısından, Karabucak-111, diğer deneme alanlarına göre daha yüksek değerlere sahip olmuştur. Her üç deneme alanının birlikte değerlendirilmesi sonucunda klonlar arasında istatistiksel olarak fark olduğu; G96 klonun, özellikle hacim gelişimi bakımından en yüksek değerlere sahip olup ilk sırada yer aldığı görülmüştür. 5. yaş sonunda, bütün deneme alanlarında büyüme bakımından saf türleri geçen hiçbir melez klonun bulunmamasına rağmen başarılı klonların arasında yer alan verimli üç melez klon (M77, M85 ve M46) ümit verici görülmüştür.

Wood ash content variation in Eucalyptus grandis clones in Mozambique

The sustainability of native forests in Sub-Saharan Africa depends on the diversification of sources to generate bioenergy, and Eucalyptus spp. wood has been highlighted. However, the determination of energy quality parameters has been a challenge to enable plantation wood to generate energy. The research assessed the ash content of radial and longitudinal samples of Eucalyptus grandis (Hill) clone with different ages and growth sites. Samples were collected in three pre-established plots in the center of Mozambique. Five trees were cut down in each plot and six discs were removed from each tree. Grinded samples with <0.5 mm particle size were generated from the heartwood and sapwood of each disk to determine the ash content. Wood from 7-year-olds had a higher ash content compared to 9-year-olds. The two sample plots differed from each other in terms of wood ash content. Heartwood samples had smaller ash content than sapwood samples. In general, the ash content of the intermediate positions was lower than those from the base and top of the stem, for both radial sections. No conclusive differences were found between samples from the base and the top of the trees, indicating that the material from the top of the trees can also be used as wood fuel. Ash content can be a considerable parameter to assess the quality of the wood of Eucalyptus spp. as a fuel.

Assessment of the cytogenetics and leaf anatomy of synthetic polyploids of Eucalyptus clones

The induction of polyploidy in Eucalyptus can lead to higher-yielding and more adapted clones, with better wood quality. After artificial polyploidization, it is necessary to certify the effectiveness of the process through cytogenetic analyses and anatomical trait evaluations. Thus, the aim of this study was to certify the chromosome duplication in artificially polyploidized clones of Eucalyptus grandis × Eucalyptus urophylla using cytogenetic analysis, flow cytometry, and leaf anatomy measurements. Chromosomal counts and DNA content estimation allowed the identification of artificially polyploidized clones and mixoploids. Polyploid clones had larger stomata diameter than diploids. The increase in stomata size was accompanied by lower stomatal density in most polyploid clones. The typical gigas effect of polyploidized plants was demonstrated by the expressive increase in leaf area in polyploid individuals compared to diploids. Our findings indicate that the use of polyploidy in Eucalyptus breeding is promising, allowing the discrimination of diploid, tetraploid, and mixoploid plants.

Effect of drought stress on the formation and lignification of eucalyptus wood cells

Summary Environmental adaptation and cell differentiation processes are factors that influence the anatomical elements of wood. The objective of this study was to investigate the effect of water deficit on lignin composition in anatomical elements and on the characteristics of vessel-neighboring cells. Six-year-old clones of Eucalyptus urophylla and Eucalyptus grandis × Eucalyptus camaldulensis from wet and dry regions were used. All regions received a rainfall exclusion treatment. Cell wall width, cell wall thickness, and form factor of fibers close to and far from vessels were measured. In the same cells, lignin was measured in the middle lamella and vessels by a fluorescence technique. The vessel differentiation process affected cell wall thickness and lignin composition in neighboring cells. Lignin composition was increased in vessels compared to fibers or vasicentric tracheids. Middle lamella lignin was not affected by vessel differentiation or water deficit in either eucalyptus clone. E. grandis × E. camaldulensis is originally from a dry climate region and, therefore, did not suffer alterations in lignin when subjected to water stress conditions; however, this clone exhibited a higher number of vasicentric tracheids. E. urophylla is originally from a humid climate region and, when subjected to water deficit, showed increased wood lignin composition, which seems to be a strategy for better use of water resources. Alterations in lignin composition of vessel, vasicentric tracheid, and fiber cell walls resulting from exposure to water deficit conditions vary according to eucalyptus species.

Influence of Two Cutting Propagation Systems on Early Field Growth of Four Eucalyptus urophylla × Eucalyptus grandis Clones in the Republic of Congo

Influence of Two Cutting Propagation Systems on Early Field Growth of Four Eucalyptus urophylla × Eucalyptus grandis Clones in the Republic of Congo

Use of Eucalyptus grandis clones treated with a water repellent to improve the dimensional stability of utility poles

Wood is a common construction material used in most environments. However, its sensibility to abiotic agents, in particular those that affect the dimensional stability, limits the materials durability and decreases its properties. In this work, the efficiency of a paraffin-emulsion-based product as a water repellent, combined with the selection of Eucalyptus grandis clones with a low cracking index, was tested for its use in utility poles in order to improve the woods dimensional stability. Four selected Eucalyptus grandis clones were treated with the product mixed with Chromated Copper Arsenate - the most commonly used wood protector - in a single stage by the Bethell method at two retention levels. The dimensional stability of the treated samples was studied through the determination of anti-shrink efficiency. Test samples were also exposed to accelerated weathering processes for 200 h, and later analyzed by SEM microscopy. Results showed a significant improvement in the dimensional stability of treated wood when compared to samples without the water repellent, with variable efficacy depending on the clone used. Despite the weathering process slightly affected the appearance of the wood surface, the product is suitable for exterior use

Morphological and kinetic parameters of the absorption of nitrogen forms for selection of Eucalyptus clones

Eucalyptus clones are selected according to productivity, wood quality, rooting capacity, and resistance to drought, frost and diseases. However, kinetic and morphological parameters that determine the absorption efficiency of nutrients such as nitrate (NO3−) and ammonium (NH4+) are often not considered in breeding programs. The objective of this study was to evaluate the morphological, physiological and kinetic parameters of nitrogen uptake by clones of Eucalyptus saligna (32,864) and Eucalyptus grandis (GPC 23). Morphological parameters in shoot and root systems, biomass and N concentrations in different organs, photosynthetic pigment concentrations, parameters of chlorophyll a fluorescence and photosynthetic rates were evaluated. Kinetic parameters, maximum absorption velocity (Vmax), Michaelis–Menten constant (Km), minimum concentration (Cmin) and influx (I) were calculated for NO3− and NH4+ in the two clones. E. grandis clone was more efficient in the uptake of NO3− and NH4+, and showed lower Km and Cmin values, allowing for the absorption of nitrogen at low concentrations due to the high affinity of the absorption sites of clone roots to NO3− and NH4+. Higher root lengths, area and volume helped the E. grandis clone in absorption efficiency and consequently, resulted in higher root and shoot biomass. The E. saligna clone had higher Km and Cmin for NO3− and NH4+, indicating adaptation to environments with higher N availability. The results of NO3− and NH4+ kinetic parameters indicate that they can be used in Eucalyptus clone selection and breeding programs as they can predict the ability of clones to absorb NO3− and NH4+ at different concentrations.

Nitrogen supply methods affect the root growth dynamics in Eucalyptus grandis

Sandy soils presenting low organic matter levels do not provide enough N to meet Eucalyptus sp. demands. Nitrogen fertilizers can be applied to soil surface, although N losses tend to happen and to decrease the amounts of this component used by plants. Alternatively, N can be applied to planting pits at seedling transplantation time or to small holes dug close to the plants. However, aspects such as the impact of different N supply modes applied to the soil on the growth parameters of root systems and the way these supply modes can affect morphological and physiological parameters of the shoot remain poorly known. The aim of the current study is to assess shoot and root growth in Eucalyptus grandis trees grown in soil subjected to different N supply modes. Eucalyptus grandis clones (GPC 23) were subjected to three N supply modes, namely: control (without N application) (C), N application to soil surface (SN) and N application to the pit (PN). Plant height, stem diameter, N concentration and chlorophyll a fluorescence in leaves, morphological parameters of the root system (total root surface area and mean root diameter), total length of active roots and total number of living and dead roots were analyzed. The PN supply mode has led to the highest mineral N levels (NH4+ and NO3−) in the soil, as well as increased the total length of active roots, the number of living roots and the root surface area in soil layers 20–40 cm and 40–60 cm. This process has enabled greater N uptake by plants, which, in its turn, has increased N concentrations in leaves, favored photosynthetic processes and resulted in taller plants presenting greater stem diameter. The SN supply method did not increase the mineral N in the soil, and it restricted the total length of active roots in soil layer (0–20 cm) and resulted in higher mean root diameter.

Effect of growth stress and interlocked grain on splitting of seven different hybrid clones ofEucalyptus grandis×Eucalyptus urophyllawood

AbstractTrees with high levels of growth stress begin to show log end splits (LES) immediately after harvesting, usually reaching its maximum end split in a week, and these tensions also create splits during lumber manufacturing. Interlocked grain is another characteristic that impacts the properties of eucalyptus wood. The aim of this study was to evaluate the effect of growth stress and interlocked grain patterns on log end splitting of seven different hybrid clones ofEucalyptus grandis × Eucalyptus urophyllaplanted in Brazil. The growth stress indicator (GSI) was measured in standing trees before harvesting. Splits were measured on logs in three different stages, and interlocked grain from wood blocks was obtained across the center of the cross-section. The results showed that LES occurred as soon as the trees were harvested; however, for better selection of clones, LES should be evaluated after a week of harvesting. There were statistically significant correlations for GSI with LES. Clones that presented higher values of interlocked grain tended to develop lower values of GSI and LES. Using GSI and interlocked grain measurements, it was possible to select the most indicated eucalyptus clones for lumber production.

INFLUENCE OF THE REPLANTING AGE ON YIELD AND GROWTH OF EUCALYPT CLONAL STANDS

ABSTRACT The growth of an eucalypt plantation should be monitored to identify factors that influence its development, helping in the decision-making process, aiming to reduce productivity losses. Thus, the objective of the present study was to evaluate the influence of the age of replanting on the yield and growth of eucalypt stands. The experiment was conducted in an area of CENIBRA S.A. Company, and established in a commercial plantation in August 2011. The application of herbicide and the ant control were performed in total area before planting. Seedlings of Eucalyptus urophylla × Eucalyptus grandis clones in 3.0 × 2.5 m spacing were used. Limestone (1,500 kg ha-1) was applied in total area before planting and 100 g plant-1 of NPK fertilizer (06-30-06) was applied immediately after planting. Four months after the installation of the experiment, 300 kg ha-1 of NPK (06-10-29) was applied. Treatments consisted of four dates of seedling replanting (0, 20, 40 and 80 days after planting) without complementary fertilization, and two treatments (replanting 40 and 80 days after planting) with supplementary fertilization (100g plant-1 NPK 06-30-06). The individual volume of replanting trees was 46.6% lower than of non-replanted ones. Treatments with complementary planting fertilization did not differ (p > 0.05) by the T-test. It is concluded that the longer the time between planting and replanting, the smaller the individual volume of the replanting trees and that the complementary fertilization in seedlings replanted does not favor their growth.

Defoliation by insects reduces the wood quality and cellulosic pulp production

Abstract Defoliating insects damage forest plantations, but the estimation of their losses does not take into account wood quality changes. The objective was to evaluate the wood quality and pulp production of two clones of Eucalyptus grandis × Eucalyptus urophylla (clone A) and Eucalyptus saligna (clone B) damaged or not by defoliating insects. Five healthy trees and five attacked by Gonipterus platensis Marelli (Coleoptera: Curculionidae) were selected per clone. The wood volume per hectare in the affected settlements was at least 9% lower and damaged trees showed lower wood basic density, with at least 4.6%. The lignin and extractive content in the wood increased by at least 5.6 and 45%, respectively, while the syringyl/guaiacyl (S/G) ratio remained constant for clone A and increased 10% for clone B. For pulps, an increased effective alkali and decreased pulp yield were experienced for both clones while bleaching or pulp quality was not affected. In the stands affected by defoliating insects, productivity was 9 and 19% lower considering the wood volume per hectare and 15 and 24% considering the cellulose pulp production per hectare, respectively.

Effect of Different Varieties and Silicon Fertilizer on the Rooting Efficiency and Productivity of Mini-Cuttings and Powdery Mildew Disease of Eucalypt

Considering that silicon (Si) is a nutrient that stands out in the control of fungal diseases and in the increase in productivity of several cultures, this study intend to evaluate its influence on the productivity and severity of mildew in mini-stumps, as well as rooting of eucalyptus mini-cuttings. The experiment was carried out in a randomized block design with four replications in split plot scheme, the first factor related to Silicon doses (0, 0.5, 1.0, 1.5 and 2 mmol L-1) and the second factor related to five clones of Eucalyptus grandis x Eucalyptus urophylla hybrids (I144, I224, 3334, GG100, GG680). The following variables were evaluated: Si content in mini-cuttings, powdery mildew severity and mini-stumps productivity, and rooting of mini-cuttings. The highest absorption of Si was obtained with a dose of 1.22 mmol L-1 (0.14%). There was no influence of the nutrient solution containing Si on the productivity of mini-stumps, powdery mildew severity or rooting of eucalyptus mini-cuttings. Clones GG100 and 3334 presented, respectively, the best and worst results for all evaluated variables.

Phosphorus, nitrogen and potassium nutrition on Calonectria leaf blight in eucalypt plants

AbstractCalonectria pteridis causes Calonectria leaf blight (CLB), and consequently severe defoliation in eucalypt plantations, which results in losses in wood volume. To reduce the negative impacts of this disease in eucalypt, this study aimed to assess the application of different doses and combinations of the macronutrients N, P and K on the percentage of symptomatic leaf area (SLA) and defoliation induced by the pathogen. Cuttings of a clone of Eucalyptus grandis were transplanted to pots containing soil that received different dose combinations of N, P and K, according to an incomplete factorial design. At 200 days after transplanting, leaf samples were analysed for N, P and K contents, and then, the plants were inoculated. Forty‐five days post‐inoculation, SLA and percentage of defoliation were quantified. Potassium doses above 75 mg/dm3 of soil significantly reduced SLA and defoliation. The influence of N and P on defoliation was dependent on K doses, but both reduced symptomatic leaf area. The best control of the disease, expressed by decreased defoliation and symptomatic leaf area, was achieved with leaf content of N, P and K of 9.8, 0.8 and 10.4 g per kg leaf, respectively, obtained with doses of 55, 82.5 and 143 mg/dm3of soil, respectively. Therefore, N, P and K nutrition can be a component of an integrated management programme for the control of CLB in eucalypts.

QUALITY OF Eucalyptus urograndis CHARCOAL PRODUCED IN THE SOUTHERN REGION OF TOCANTINS

The objective of this work was to determine the quality of the Eucalyptus urophilla x Eucalyptus grandis clone charcoal, defining the basic density and wood retractability, apparent density, breaking index, charcoal yield, condensable and non-condensable gas yield, AQI and calorific values, comparing the results of different trunk positions and in two different heating ramps, ramp 1 (R1) with a heating rate of 1.25 ºC/min, final temperature of 450ºC and total of 6 hours, and ramp 2 (R2) with a heating rate of 1.19 ºC/min, final temperature of 500ºC and total time of 7 hours. The six evaluated trees were from a six-year-old cloned tree plantation located in the municipality of Gurupi, in the south of Tocantins state. The specimens for the characterizations were made from wooden discs removed from three trunk positions (base, DBH, top). The Eucalyptus urograndis wood presented basic density considered average (0.47 g/cm³) and good dimensional stability. The charcoal presented an expected yield and high calorific value influenced by the final temperature of the heating ramps, high fixed carbon content, acceptable ash content, as well as a low breaking rate. The results were satisfactory and identified the species as a good energy source.

GROWTH AND VOLUMETRIC PRODUCTION OF EUCALYPTUS CLONES IN DIFFERENT PLANTING SPACES

In forest stands, the ideal planting spacing can provide each tree with enough space for its establishment, aiming at greater growth and wood quality, according to the objective of planting. The objective of this study was to evaluate the growth in height, diameter, and volumetric production of three eucalyptus clones planted in different spacings. The experiment was carried out in an area belonging to Campo Bom Farm, in Chapadão do Sul, MS. A randomized block design was used in a factorial scheme, combining six spacings (2.5 x 0.5 m; 2.5 x 1.0 m; 2.5 x 2.0 m; 3.0 x 0.5 m; 3.0 x 1.0 m and 3.0 x 2.0 m) and three clone of Eucalyptus grandis x Eucalyptus urophylla (GG 680, GG 157 and GG 100) with three replications. The diameter at breast height (DBH) and height of all plants were evaluated at 12, 18, 24, and 32 months after planting. At 32 months, the cubage of a tree per plot was performed to obtain the volume of wood per tree and hectare. In the largest spacings, the highest average plant heights were observed. The growth of plant height was reduced from 24 months of age, except for the GG 680 clone, at 2.5 x 2.0 m and 2.5 x 1.0 m spacings, and in GG 100 clone, at 2.5 x 1.0 m spacing. The average diameter and volume per tree increased with the spacing for the three clones, while the volume per area was higher in the denser spacing. Wood volume production per area was dependent on the spacing used for the three clones.

Interactions between the mechanical and hydraulic properties of Eucalyptus trees under different environmental conditions of fertilization and water availability

Water and potassium are limiting factors for tree growth. Their influence on morphology and anatomy are well known, but their combined effects on tree growth remain to be clarified. A single clone of Eucalyptus grandis was analyzed under different treatments of rainfall exclusion and fertilization. Eight trees per treatment were sampled to investigate the influence of these treatments on the morphological, mechanical, and anatomical traits. The results showed that the fertilization mainly influenced the morphological and anatomical characteristics. Considering the difference between the fertilized and non-fertilized trees, the function of mechanical support was provided through increasing the diameter and the stiffness. Considering the fertilized trees, two different mechanisms occurred inducing a high stiffness: the wood density was higher for trees with rainfall exclusion; the specific modulus was higher for trees with a normal water supply.

Differential Tolerance of Clones of Eucalyptus grandis Exposed to Drift of the Herbicides Carfentrazone-Ethyl and Glyphosate

ABSTRACT: Drift of the herbicides carfentrazone-ethyl and glyphosate may affect the initial growth of eucalyptus. This study aimed to assess the effect of carfentrazone-ethyl and glyphosate drift on photosynthesis, leaf morphoanatomy, and initial growth of two clones of Eucalyptus grandis. Two experiments were carried out in a 2 x 4 factorial scheme, in which factor 1 was represented by two clones of E. grandis and factor 2 by four herbicide underdoses (control, 86.4 g a.e. ha-1 of glyphosate, 3.0 g a.e. ha-1 of carfentrazone-ethyl, and the mixture of 86.4 g a.e. ha-1 of glyphosate + 3.0 g a.e. ha-1 of carfentrazone-ethyl). Herbicide application was carried out by simulating the drift in the lower third of seedling canopy. Assessments were performed 23 days after herbicide application. Both clones presented morphoanatomical changes such as erosion of epicuticular waxes and degeneration of epidermal and parenchymal cells, especially when exposed to carfentrazone-ethyl underdose or its mixture with glyphosate. The clone CLR 383 was the most affected by the tested herbicides and presented the highest injury, lowest initial growth, lowest dry matter, and highest reduction of photosynthetic rate when treated with herbicide mixture, followed by carfentrazone-ethyl and glyphosate underdoses. The initial growth, dry matter, and photosynthesis of the clone CLR 384 were not affected by the carfentrazone-ethyl underdose. Thus, both herbicides applied in isolation or in a mixture reduced the initial growth, dry matter, and photosynthesis of eucalyptus.

Correlations between Eucalyptus Clonal Cutting Quality and Performance after Planting

ABSTRACT This study assessed correlations of different characteristics of cuttings in the nursery of three hybrid clones of Eucalyptus grandis × Eucalyptus urophylla and growth in height after planting. The characteristic that presented greatest correlation with the initial growth was the canopy height and cutting height ratio. At 12 and 24 months in the field, the stem diameter was more important. The parameters assessed in the nursery that correlated positively with growth in the field at three and six months after planting were height, number of leaf pairs, number of root deformations and clod length. At 12 and 24 months the parameters that correlated negatively were diameter, number of leaf pairs and the number of root deformations. Despite presenting significant correlation, root deformations did not interfere in the initial growth of the plants under high rainfall conditions, but the effects became harmful over time resulting in a reduction in plant growth.

Influence of moisture content on the axial resistance and modulus of elasticity of clonal eucalyptus wood

Abstract The mechanical and physical properties of wood are important factors used to determining the suitability and application of wood material. Modulus of elasticity and resistance values of wood which is changed according to the factors such as, temperature, moisture content, and density. Obtained results in this study show that the modulus of elasticity and the axial resistance for studied clones woods increase when the wood moisture decreases. According to the stress of rupture, both woods are classified within the range of weak stress. In addition, these results show that Eucalyptus grandis clone 3758 has a high modulus of elasticity in compression and low axial resistance compared to E. camaldulensis clone 579.