Showing papers on "Eucalyptus camaldulensis published in 2005"

Hydrological consequences of Eucalyptus afforestation in the Argentine Pampas

Abstract: [1] The impacts of a 40 ha stand of Eucalyptus camaldulensis in the Pampas grasslands of Argentina were explored for 2 years using a novel combination of sap flow, groundwater data, soil moisture measurements, and modeling. Sap flow measurements showed transpiration rates of 2–3.7 mm d−1, lowering groundwater levels by more than 0.5 m with respect to the surrounding grassland. This hydraulic gradient induced flow from the grassland areas into the plantation and resulted in a rising of the plantation water table at night. Groundwater use estimated from diurnal water table fluctuations correlated well with sap flow (p < 0.001, r2 = 0.78). Differences between daily sap flow and the estimates of groundwater use were proportional to changes in surface soil moisture content (p < 0.001, r2 = 0.75). E. camaldulensis therefore used both groundwater and vadose zone moisture sources, depending on soil water availability. Model results suggest that groundwater sources represented ∼67% of total annual water use.

The antimicrobial activities of methanolic extracts of Eucalyptus camaldulensis and Terminalia catappa against some pathogenic microorganisms

Abstract: Methanolic extracts of leaves of Eucalyptus camaldulensis and Terminalia catappa were studied for in vitro microbial activities by agar dilution method. The phytochemical analysis of the crude extracts of the medicinal plants revealed the presence of saponin, saponin glycosides, steroid, cardiac glycoside, tannins, volatile oils, phenols and balsam (gum). The methanolic extracts of the two plants inhibited the growth of Bacillus subtilis and Staphylococcus aureus (ATCC 103207 and Clinical strain respectively) but had no inhibitory effects on Pseudomonas aeruginosa, Salmonella typhi and Escherichia coli. Candida albicans was inhibited by the crude extracts of E. camaldulensis only. Accelerated gradient chromatography (AGC) gave fractions of the extract of T. catappa that were more active on Candida albicans and Escherichia coli than the crude extract. The minimum inhibitory concentration (MIC) of the extracts ranged from 1.25�g/ml to 5�g/ml. The results obtained suggest that T. catappa and E. camaldulensis can be used in treating diseases caused by the test organisms.

Variations in compression strength and surface roughness of heat-treated Turkish river red gum ( Eucalyptus camaldulensis ) wood

Abstract: This article reports the effects of heat treatment on compression strength parallel to the grain, the surface roughness [average roughness (Ra)], and the air-dry den-sity of wood from the river red gum tree (Eucalyptus camaldulensis Dehn.) planted in Turkey. Eucalyptus wood was heat-treated at temperatures varying from 120° to 180°C for durations of 2–10 h. Samples cut from the heat-treated wood were tested for air-dry density, compression strength parallel to grain, and surface roughness properties. Roughness measurements by the stylus method were made in the direction perpendicular to the fiber. Based on the findings in this study, the results showed that density, compression strength, and surface roughness values decreased with increasing treatment temperature and treatment times. Eucalyptus wood could be utilized by using proper heat treatment techniques without any losses in strength values in areas where working, stability, and surface smoothness, such as in window frames, are important factors.

Thaumastocoris australicus Kirkaldy (Heteroptera: Thaumastocoridae): a new insect arrival in South Africa, damaging to Eucalyptus trees.

Abstract: The insect thaumastocoris australicus Kirkaldy is reported from South Africa, where it probably is a recent arrival from Australia. The species was originally described from Queensland, but in recent years has taken on pest proportions on some local and planted lIgEucalyptusl/Ig species in Sydney, New South Wales. In Gauteng province, South Africa, these gregarious, leaf-sucking bugs primarily infest introduced river red gum trees ( Eucalyptus camaldulensisl/Ig Dehnh.), causing, or contributing to, discoloration of the leaves, dieback of branches or mortality of entire trees. Several other lIgEucalyptusl/Ig species also serve as hosts for T. australicusl/Ig and some are heavily infested and severely damaged. There are confirmed reports of their presence in Gauteng, Mpumalanga and North West provinces but they are possibly already widely distributed in South Africa. Their known distribution in Australia and the localities where they already thrive in South Africa suggest that few climatic regions in southern Africa would be unsuitable for the bugs. The mature and immature insects are of nuisance value and are irritating and hard to dislodge when they fall onto people from infested trees. The possible threats to forestry and beekeeping industries have not been evaluated, but are potentially severe. No effective control measures currently exist and no insecticides have been registered for use against the pest.

Population status of eucalypt trees on the River Murray floodplain, South Australia

Abstract: For populations to persist, recruitment must keep pace with mortality. In variable environments, opportunities for reproduction occur patchily in time and space, and favourable conditions must occur sufficiently often to allow growth to maturity (hence 'recruitment'). The risks of local extinctions may be increased by anthropogenic factors. This scenario is illustrated by two tree species, river red gum (Eucalyptus camaldulensis) and black box (E. largiflorens), on the floodplain of the River Murray, South Australia. Fixed area plots were established at Banrock Station, where large, mature trees are common, although red gum outnumber black box by about four to one. Trunk diameter was measured as a surrogate for tree age. The smallest diameter (0-10cm) black box are nearly as common as seedlings of that species, whereas the smallest diameter red gum (0-10 cm) are 10 times more abundant than seedlings. Small trees of both species occur in localized clumps, and the respective size-class distributions exhibit series of peaks and falls, suggesting episodic recruitment and opportunistic survival. Population viability calculations suggest that more than 100% of existing saplings need to survive to maintain the local black box population (i.e. there are too few saplings). The red gum population apparently requires a smaller proportion of survivors, but the calculations may be biased by the clumped distribution of the saplings. Based on population structure and viability estimates, black box at this site appear to lack sufficient regeneration to compensate for adult mortality while red gum appear to have a much better balance. The methods established here may be useful for assessment of stands of these species in other areas.

Anti dermatophyte activities of eucalyptus camaldulensis in comparison with griseofulvin

Abstract: Methanolic leaf extracts of Eucalyptus camaldulensis were investigated for in vitro antifungal activities against Microsporum canis, Microsporum gypseum, Tricophyton rubrum, Tricophyton schoenleinii, Tricophyton mentagrophytes and Epedermophyton floccosum. The studies were carried out using broth dilution method, agar dilution method and inhibitory zone estimation. The effects of the plant extract were compared with those of griseofulvin. Eucalyptus camaldulensis showed antifungal activity against all the dermatophytes tested with MIC values ranging from 0.4 to 1.6 mg/mL using inhibitory zone estimation, 0.4-1.6 mg/mL using agar dilution method and 0.2 to 1.6 mg/mL using broth dilution method. The minimum fungicidal concentration (MFC) of the extracts ranged from 0.8 to 6.4 mg/mL. The results obtained suggest that E. Camaldulensis has anti-dermatophyte activity.

Rapid assessment of wood chemical properties and pulp yield of Eucalyptus camaldulensis in Thailand tree plantations by near infrared spectroscopy for improving wood selection for high quality pulp

Abstract: Near-infrared (NIR) spectroscopy has been demonstrated as a means for rapid nondestructive determination of the chemical composition and final pulp yield of Eucalyptus camaldulensis in Thailand tree plantations. Multiple linear regression (MLR) analysis and partial least squares (PLS) analysis were introduced to develop statistical models in terms of calibration equations for total pulp yield, screened pulp yield, and contents of α-cellulose, pentosans, and lignin in wood. In MLR analysis, a reasonably good calibration equation was found only for pentosans (standard error of prediction (SEP): 0.98%). The PLS analysis improved the accuracy of prediction for every criterion variable, especially for pentosans (SEP: 0.91%) and lignin (SEP: 0.52%). Also, in the case of screened pulp yield, we were able to use such a statistical result as an indicator of the characteristics of the pulp and paper. Thus, NIR spectroscopy could be satisfactorily used as an effective assessment technique for Eucalyptus camaldulensis plantation trees.

Aluminum tolerance and aluminum-induced deposition of callose and lignin in the root tips of Melaleuca and Eucalyptus species

Abstract: We exposed the roots of nine Myrtaceae species (Melaleuca bracteata F. Muell., Melaleuca cajuputi Powell, Melaleuca glomerata F. Muell., Melaleuca leucadendra [L.] L., Melaleuca quinquenervia [Cav.] S.T. Blake, Melaleuca viridiflora Sol. ex Gaertner, Eucalyptus camaldulensis Dehnh., Eucalyptus deglupta Bl., and Eucalyptus grandis W. Hill ex Maiden) to 1 mM Al in a nutrient solution for either 24 h or 20 days to evaluate their sensitivity to excess Al and to determine whether callose and lignin formation can be used as interspecific indicators of Al sensitivity. Inhibition of root elongation by Al varied among the species. Melaleuca leucadendra, M. cajuputi, E. grandis, M. quinquenervia, and E. deglupta were tolerant to 1 mM Al, whereas M. viridiflora, E. camaldulensis, M. glomerata, and M. bracteata were sensitive to 1 mM Al. We found that Al induced callose formation in the root tips of each species, but lignin was formed only in the root tips of the most sensitive species, M. bracteata. Root elongation at 1 mM Al was negatively correlated with Al-induced callose formation but not with the Al-induced lignin formation in the root tips. These results suggest that Al-induced callose formation, rather than lignin formation, can be used as an interspecific indicator of Al sensitivity.

Plant regeneration from cotyledonary explants of Eucalyptus camaldulensis

Abstract: Breeding methods based on genetic transformation techniques need to be implemented for Eucalyptus camaldulensis to shorten the long breeding cycles and avoid manipulation of adult trees; that requires the development of plant regeneration protocols enabling development of plants from transformed tissues. The present work aimed to optimise the regeneration process already established for the species. Cotyledonary leaves of E. camaldulensis were cultured in MS medium supplemented with naphthaleneacetic acid (NAA) and 6-benzylaminopurine (BAP) combinations. The most efficient treatment for bud indirect regeneration (2.7 µmol L-1 NAA and 4.44 µmol L-1 BAP) was used for further experiments. When explants were kept in the dark during the first 30 days, the percentage of explants forming calluses increased and explant necrosis was reduced in comparison with light-cultured explants. Mineral medium modifications were compared and half-strength MS mineral medium turned out to be as efficient as full-strength medium, producing 54% and 47% of explants with buds, respectively. For shoot elongation, MS medium with half-strength nitrate and ammonium salts, and 0.2% activated charcoal yielded rooted shoots 1 to 8 cm high after one month. The procedure is an efficient protocol for E. camadulensis plant regeneration, reducing the stages necessary for the obtention of complete plants.

Isolation of Cryptococcus gattii and Cryptococcus neoformans var. grubii from the flowers and bark of Eucalyptus trees in India

Abstract: The association of Cryptococcus gattii with Eucalyptus trees has been well established. Here we report the isolation of both C. gattii and Cryptococcus neoformans var. grubii from the flowers and bark of Eucalyptus trees in India. We investigated a total of 233 samples of Eucalyptus trees: 120 flowers, 81 fragments of bark, and 32 leaves. C. gattii was isolated from two samples of flowers of Eucalyptus terreticornis. C. neoformans var. grubii was recovered twice from the bark of Eucalyptus camaldulensis, initially from one of three samples, and again 2 months later, from one of four samples collected beneath the canopy of the tree. The primary isolation medium was Nigerseed agar, and brown colonies were presumptively identified as C. gattii or C. neoformans. The species identification was confirmed by morphological and biochemical characteristics. Using the Crypto-Check kit (Iatron, Tokyo, Japan), the first two isolates were identified as serotype B (C. gattii) and the other two were serotype A (C. neoformans var. grubii). PCR analysis of the isolates of C. neoformans var. grubii revealed that they possessed the MATalpha mating type allele. Molecular typing by amplified fragment length polymorphism markers indicated that both isolates of C. neoformans var. grubii possessed the same genotype. This study demonstrates that C. neoformans var. grubii, as well as C. gattii, may be associated with Eucalyptus trees.

Radial Variations of Anatomical Characteristics and Specific gravity in Eucalyptus Camaldulensis Clones

Abstract: Five superior clones of Eucalyptus camaldulensis from in vitro propagation or tissue culture at the Sra Keaw plantation site in the eastern part of Thailand were selected for examining radial variations of anatomical characteristics and specific gravity. The age of the clones was 5 years at harvest. A 9-year-old tree grown from seed in the same site was also investigated. Results were as follows: 1) Mean specific gravity showed significantly different values among the 5 clones and the seedling. 2) Vessel density rapidly decreased in the first 2–4 cm from the pith in the clones and in 5 cm from the pith in the seedling. 3) Fiber lengths of the clones slowly increased from the pith outwards, while that of the seedling rapidly increased. 4) Each clone and the seedling had a different specific gravity and anatomical characteristics. 5) Clones had a narrower juvenile wood zone than the seedling due to the older cambial age of the clones.

Examination of within-tree variations and the heights representing whole-tree values of derived wood properties for quasi-non-destructive breeding of Eucalyptus camaldulensis and Eucalyptus globulus as quality pulpwood

Abstract: Within-tree variations of derived wood properties of Runkel ratio, Luce’s shape factor, slenderness ratio, and solids factor were examined for Eucalyptus camaldulensis and Eucalyptus globulus trees and the tendency difference in the within-tree variations between individuals and between species, in both radial and axial directions by statistical data analysis. These properties are important for quality breeding of pulpwood. In both species, within-tree variations were generally observed as higher values in the upper and outer parts compared with other parts of the trunk for Runkel ratio and Luce’s shape factor. In E. camaldulensis, within-tree variations were observed as higher values in the upper and outer parts compared with other parts of the trunk for slenderness ratio and solids factor. In E. globulus, within-tree variations were observed as higher values in the outer parts compared with other parts for slenderness ratio and solids factor. However, significant difference of tendency was observed in radial variation between individuals of E. globulus for Runkel ratio and in both radial and axial variations between species for solids factor. Furthermore, within-tree variations of derived wood properties were analyzed to determine a sampling height in the trunk which can be used to represent whole-tree values. Representative heights of derived wood properties from two trees were found to be 2.8 m in E. camaldulensis (except for Runkel ratio and Luce’s shape factor) and 1.8 m in E. globules (except for Runkel ratio), regardless of differences in tree height (growth rate) and in tendency of within-tree variation of derived wood properties.

Properties of bamboo-rice straw-eucalyptus composite panels

Abstract: This study investigated some of the important properties of single-layer particleboard panels made from bamboo (Dendrocalamus asper), rice straw, eucalyptus (Eucalyptus camaldulensis), or combinations of them A total of 40 experimental panels were manufactured from each material type Panels were also made using a 50:50 ratio of eucalyptus and bamboo, eucalyptus and rice straw, and bamboo and rice straw; a 50:25:25 ratio of eucalyptus, rice straw, and bamboo; and a 70:15:15 ratio of eucalyptus, rice straw, and bamboo, respectively Average target density of the panels ranged from 075 to 078 g/cm 3 Modulus of rupture, modulus of elasticity, internal bond strength, thickness swelling, water absorption, density profiles, and surface roughness of the specimens were determined Panels with 50:50 bamboo and eucalyptus particles resulted in the highest mechanical properties followed by panels made from 100 percent bamboo Boards manufactured with 100 percent rice straw produced the lowest properties The amount of rice straw in the panels significantly reduced both physical and mechanical properties of the samples The overall panel properties improved as lower percentage of rice straw were added to the mats Based on initial results of this study, three under-utilized species can be used to manufacture value-added particleboard panels It also appears that an addition of rice straw into the mats should be less than 15 percent to achieve better panel properties

Distribución ambiental de Cryptococcus neoformans en el departamento de Cundinamarca-Colombia

Abstract: Cryptococcus neoformans is an opportunistic fungal pathogen that could cause infection in patients with immunodeficiency and healthy patients. The AIDS epidemic has shown the importance of studying the ecology and epidemiology of this fungus. The aim of this investigation was to determine if there was a relationship between the environmental distribution of the different varieties of C. neoformans and the climate zones in two transects located in department of Cundinamarca, in Colombia. For the isolation and identification of the yeast, conventional phenotypic methods were used and it was determined the population density (CFU/g of sample) and which was the variety of greater prevalence in each altitudinal rank. A total of 765 samples, from 26 municipalities were collected; of these 146 corresponded to pigeon droppings (Columba livia), 437 to Eucalyptus detritus (Eucalyptus camaldulensis and related species) and 182 to detritus of almond trees (Terminalia cattapa). C. neoformans was isolated from 46% of the studied municipalities, in both transects and the climate zones: warm, temperate and cold. The results indicated that the greater frequency of positive isolations came from the last climate zone (cold). The population density in pigeon excrements oscillated between 50 and 9.2 x 1,000,000, in eucalyptus between 500 and 10 x 1,000,000 and in almond trees was 50 CFU/g. Of 100,000 positive isolations 31% were serotype A, 59% serotype B and 10% serotype C; 96% of the isolates grew to 37 degrees C and all showed capsule. In conclusion, C. neoformans prevails in the three habitats studied but it showed a predilection for the cold thermal floor; the population densities did not allow defining a standard pattern of occurrence.

Occurrence of Lectocybe invasa Fisher & La Salle, 2004 (Hymenoptera: Chalcidoidea) on Eucalyptus camaldulensis in Turkey, with a description of the male sex

Abstract: (2005). Occurrence of Lectocybe invasa Fisher & La Salle, 2004 (Hymenoptera: Chalcidoidea) on Eucalyptus camaldulensis in Turkey, with a description of the male sex. Zoology in the Middle East: Vol. 35, No. 1, pp. 112-114.

ACÚMULO DE NUTRIENTES NA PARTE AÉREA, NA SERAPILHEIRA ACUMULADA SOBRE O SOLO E DECOMPOSIÇÃO DE FILÓDIOS DE Acacia mangium Willd.

Abstract: A survey of Scolytidae population of species of Scolytidae family was made in plantations of Eucalyptus camaldulensis Dehnh, Eucalyptus citriodora Hook. f. , Eucalyptus pellita F. Muell. and Eucalyptus urophylla S.T. Blake, located at Cuiaba city in Mato Grosso state from march 1998 to february 1999, with aid of ethanol traps model “escolitideo-Curitiba”. The were used 24 traps, six per Eucalyptus plot/specie. Collection was made every 15 days and divided in two periods: drought (may – October) and rRainy Season (november – april). There were collected a total of 19.153 individuals, distributed in 11 genera and 42 species. In the dry and rain periods there were collected 9.865 and 9.288 individuals, respectively. In plantations of Eucalyptus pellita and Eucalyptus urophylla were collected the largest amount of individuals, in both analyzed periods. Cryptocarenus diademantus Eggers, 1937; Cryptocarenus seriatus Eggers, 1933; Cryptocarenus heveae (Hagedorni, 1912 ); Hypothenemus obscurus (Fabricius, 1801) and Xyleborus spinosulus (Schedl, 1934) were in number, the most important in plantations of the four species of Eucalyptus .

Feeding inhibition of Helicoverpa armigera (Hübner) by Eucalyptus camaldulensis and Tylophora indica extracts

Abstract: Crude leaf extracts of Eucalyptus camaldulensis and Tylophora indica were evaluated for their antifeedancy against Helicoverpa armigera larvae in no-choice bioassays. Cabbage leaf-disc dipped in different concentrations of leaf extracts was used for feeding fifth instars of H. armigera for 24 hours. Ethanol extracts from both the plant species exhibited significant feeding inhibition activity. The effective concentrations of ethanol extracts that caused 50% reduction in larval feeding (EI50) were 6.9% for E. camaldulensis and 2.8% for T. indica, while these values of hexane extracts were 9.3% and 5.2%, respectively. Compared to the crude leaf extracts, crude alkaloids from T. indica and crude tannins from E. camaldulensis were more potent in reducing larval feedings.

Water-use efficiency and carbon isotope discrimination of Acacia ampliceps and Eucalyptus camaldulensis at different soil moisture regimes under semi-arid conditions

Abstract: Acacia ampliceps Maslin and Eucalyptus camaldulensis Dehnh. were grown for one year in lysimeters at three soil moisture regimes: 100 % (well-watered), 75 % (medium-watered) and 50 % (low-watered) of total plant available water. Biomass yield of both species increased with increase in soil moisture. Water-use efficiency (WUE) of E. camaldulensis decreased and that of A. ampliceps increased markedly with decrease in available soil moisture. A. ampliceps showed 4 − 5 times more biomass yield than E. camaldulensis grown at similar soil moisture. A. ampliceps showed almost 5, 9 and 12 times higher WUE than E. camaldulensis under low-, medium- and well-watered treatments, respectively. Significant negative correlation of δ13C with WUE (r = −0.99) was observed in A. ampliceps. In contrast, δ13C of E. camaldulensis showed a significant positive correlation with WUE (r = 0.82).

Dehydrogenase activity and VAM fungi in tree-rhizosphere of agroforestry systems in Indian arid zone

Abstract: Biological activity in tree rhizosphere and association of VAM fungi with tree-roots could be used as selection criteria for agroforestry trees in arid ecosystems. Dehydrogenase activity and VAM fungi association in rhizosphere of six agroforestry trees (Azadirachta indica, Acacia tortilis, Eucalyptus camaldulensis, Prosopis cineraria and Tecomella undulata) were studied under irrigated and rainfed conditions in the arid zone of India. Higher dehydrogenase activity (9.5 to 16.8∼p kat g soil−1), root colonization (58.3 to 68.5%) and spore density (132.5 to 234.7 spores 100 g soil−1) were observed in tree rhizosphere as compared to that in non-rhizosphere (7.4, 37.7 and 44.4). Irrigation had increased dehydrogenase activity by 22.1% while it reduced root colonization and spore density by 14.2% and 16.2%, respectively. Trees of A. indica had registered maximum growth while E. camaldulensis the least. Findings suggest that selection of A. nilotica, A. indica, and T. undulata for plantations of agroforestry in arid region would reduce the risk and ensure sustainability of the agroforestry system.

Rehabilitation of the native tree species in the forest plantations and denuded hills of Namlau commune in Sonla province, Vietnam

Abstract: This study was conducted at the Acacia and Eucalyptus plantations and an unplanted area in Vietnam to firstly compare the appearance of native tree species between different plantations and an unplanted area, and secondly to examine the effect of planting densities and distances from the natural forest to plantations on the appearance and successful growth of native tree species. The area had previously suffered from many forest fires, grazing activity and shifting cultivation until 1990, and consequently had become degraded with low species diversity, low vegetation cover and low soil fertility. Circular plots of 200 m2 were used to collect data from January to April, 2004. Several diversity indices were recorded to evaluate the species diversity in the plantations and unplanted area. A total of 22 regenerated native tree species were found in the plantation of Acacia auriculiformis with a density of 860 trees per ha. In this plantation, the best planting density was 1,660 trees per ha. The lowest densit...

Impact of Eucalyptus camaldulensis plantation on an alluvial soil in south eastern Botswana

Abstract: This paper examines the impact of a 33‐year plantation of Eucalyptus camaldulensis on an alluvial soil in Gaborone, south eastern Botswana, by comparing the soil under the plantation with similar soil under an adjoining native savanna woodland dominated by Acacia karoo Soil clay content was significantly higher in the plantation soil in both the 0–10 cm and 10–20 cm layers There were no significant differences between soil under the two ecosystems with respect to the levels of organic matter, exchangeable potassium and available phosphorus Despite the higher clay contents of the plantation soil, exchangeable calcium and magnesium and pH were higher in soil under the native woodland This suggests that E camaldulensis immobilizes soil nutrients faster and that plantation nutrient cycles are less efficient than in the native Acacia woodland Consequently, soil nutrient deficiency will limit plantation productivity after the first few rotations It is important to adopt tree harvesting techniques that re

The occurrence of hollows in eucalypts and Ironwood Erythrophleum chlorostachys in the Gulf region of the Northern Territory and its implications for timber harvesting

Abstract: The occurrence of hollows in eucalypts and Ironwood Erythrophleum chlorostachys was examined in different habitats in Limmen National Park in the Gulf Falls and Uplands bioregion of the Northern Territory. For each tree sampled, the diameter of the trunk at breast height (DBH) and numbers of hollows in three size categories were recorded. It was found that the riparian zone had the highest density of hollows per unit land area, followed by the rocky hill zone, and then the sandy flat zone. The relationship between hollows per tree and DSH was compared for four species: Eucalyptus camaldulensis (the dominant riparian tree), Eucalyptus leucophloia (the dominant tree on rocky hills), Eucalyptus miniata (the dominant tree on sandy flats), and Ironwood. E. miniata and Ironwood were found to have fewer hollows for a given DBH. It is suggested that the low incidence of hollows in Ironwood is a result of the species' know resistance to termites. The low number of hollows per Ironwood tree, the scarcity of Ironwood in the study area, and the small size of Ironwood trees relative to most of the eucalypts resulted in very few Ironwood hollows overall. This considered, harvesting of Ironwood (a preferred timber species) in this area is unlikely to have an impact on the availability of hollows to fauna. Further research is required to clarify discrepancies with other studies, and assess whether these results apply more broadly, for instance to wetter areas with larger Ironwood trees.

Study of plants visited by honeybees (Apis mellifera L.) in the Central Rif Region (N. Morocco) using pollen analysis

Abstract: Quantitative pollen analyses of Moroccan honey samples provided by amateur beekeepers from the Central Rif region demonstrates that nectar is generally the main honey source, and that most honeys have a medium‐low presence of botanical elements. However, two samples reached values as high as 1.08–1.83 qualifying as honeydew honeys. Qualitative results yielded 60 pollen types belonging to 33 families. Ammi visnaga L., Mentha pulegium L., M. rotundifolia (L.) Hudson, Eucalyptus camaldulensis Dehnh. and Rubus ulmifolius Schott. were the main nectar sources, and Cistaceae, Poaceae, Cannabis sativa L. and grasses were exploited as a pollen source. When compared to the parent vegetation honeydew and mint sources are widely exploited, but other sources such as eucalyptus and heather are underutilised.

Eucalyptus agroforestry system for small farms: 2-year experiment with rice and beans in Minas Gerais, Brazil

Abstract: In Minas Gerais, Brazil, Eucalyptus plantation agroforestry techniques for small farms appear to be an adequate alternative to small-scale plantations, and by integrating timber and food production, they can meet local demands for aliment and wood. Intercropping of Eucalyptus camaldulensis with rice and beans was studied to compare yields of intercropping and monocultures over 2 years. In the first year, no differences were found in the productivity between the intercropped and monoculture systems of E. camaldulensis, rice and beans in both seasons. In the second year, E. camaldulensis in monoculture showed the lowest productivity. If compared with E. camaldulensis intercropped with agricultural crops, during the rainy season, beans intercropped with E. camaldulensis showed similar productivity when compared to monoculture. In the dry season, the productivity of beans in monoculture was higher than intercropping. In the second year, rice productivity was very low for both systems due to the lack of precipitation during the fructification phase. The equivalence area index (EAI) confirmed the advantages of the intercropping system over the monoculture system for E. camaldulensis and beans and rice, at least in the first 2 years.

Distribution of Accumulated Aluminum and Changes in Cell Wall Polysaccharides in Eucalyptus camaldulensis and Melaleuca cajuputi under Aluminum Stress

Abstract: Distribution of aluminum (Al) within plant components and Al-induced changes in cell wall polysaccharides in root tips of Eucalyptus camaldulensis Dehnh. seedlings were compared with those of Melaleuca cajuputi Powell. In E. camaldulensis, 0.5 mM Al (pH 4.2 for 40 d) reduced plant dry weight by 50%, increased callose concentration in the root tips and induced leaf necrosis. In comparison with M. cajuputi, Al concentrations were higher in roots and leaves of E. camaldulensis on both a fresh weight basis and in the cell sap, but were lower in the cell wall. Al increased pectin, hemicellulose and cellulose concentration in the cell walls of E. camaldulensis root tips. Al-induced leaf necrosis and growth reduction in E. camaldulensis is discussed in the context of potentially toxic concentrations of Al in plant tissue and changes in polysaccharide content which could reduce water and nutrient uptake and cell wall extensibility in roots.

Efeitos do Eucalyptus camaldulensis sobre a colonização micorrízica e a nodulação em Dimorphandra mollis e Stryphnodendron adstringens, em Brasilândia, Minas Gerais

Abstract: In order to evaluate the Eucalyptus camaldulensis plantation effect on mycorrhyzal colonization and nodulation root samples of two arboreal species: Dimorphandra mollis (Fabaceae Caesalpinioideae) and Stryphnodendron adstringens (Fabaceae Mimosoideae) were analyzed. The samples were taken on strips of native cerrado, in plantation of Eucalyptus and preservation area of native cerrado (latitude of 16 o 49 S to 17 0 06 S and longitude of 45 o 40 W and 45 o 59 W) the town of Brasilândia de Minas, MG. The square X test for nodulation frequency and variance analysis (p=5%) for presence of mycorrhizas was applied for the presence mycorrhyzal. The results presented no significant differences between the treatments for the species investigated. Nevertheless, for p=10%, the statistical analysis showed that Stryphnodendron adstringens presented a variation in the mycorrhization percent within the areas studied showing that there was an effect of Eucalyptus camaldulensis on the soils affecting the population of those microorganisms . The results suggest the indication of Dimorpandra mollis for mixture with Eucalyptus camaldulensis in response to the needs of minimizing the impacts of this monoculture.

Selecting matched root architecture in tree pairs to be used for assessing N-2 fixation based on soil-(15) N-labelling

Abstract: It is commonly assumed that soil-N-15-labelling provides reliable estimates of N-2 fixation in trees by matching N-2-fixing and non-N-2-fixing tree pairs. As root system is a key parameter in determining suitability of the tree pairs, we compared root architecture of Acacia cyanophylla Lindl. and Casuarina glauca Sieber ex. Spreng. (two N-2-fixing trees) with Eucalyptus camaldulensis Dehn. and Ceratonia siliqua L. (two non-N-2-fixing trees) at 4-year-old in Mediterranean-semiarid zone. The rhizobium strain used appeared more motile than Frankia strain. A. cyanophylla and E. camaldulensis had extensive rooting area and volume of fine roots, and both species tended to develop marked horizontal rooting, compared to C. glauca and C. siliqua. Characteristics of fine- and horizontal-root components can be used in selecting matched root systems of N-2-fixing and reference-paired trees. Root architecture of C. glauca was more similar to C. siliqua, than to E. camaldulensis, and that of A. cyanophylla was more similar to E. camaldulensis than to C. siliqua. Accordingly, E. camaldulensis is an appropriate reference to estimate actual N-2 fixation by A. cyanophylla, and C. siliqua is an appropriate reference for C. glauca, when using soil-N-15-labelling method in the prevailing site environment. (c) 2004 Elsevier SAS. All rights reserved. (Less)