Acacia Mangium

Charred bark of Acacia mangium (bark charcoal), which is made of wood waste from pulp production, was applied as soil amendment for the cultivation of maize, cowpea and peanut to examine its effects on crop yield and soil chemical properties in South Sumatra, Indonesia. The yields of maize and peanut significantly increased after the application of bark charcoal under a fertilized condition in an infertile soil environment. In addition, increases in the root amount and colonization rate of arbuscular mycorrhizal (AM) fungi after bark charcoal application were also observed in maize. In general, the application of bark charcoal induced changes in soil chemical properties by increasing the pH value, total N and available P2O5 contents, cation exchange capacity, amounts of exchangeable cations and base saturation, and by decreasing the content of exchangeable Al3+. The amelioration of the soil chemical properties could be effective in highly weathered infertile tropical soils. The application of charcoal in agriculture is expected to lead to the formation of a carbon sink in soil and to increase crop yield because it has been suggested that charcoal is highly resistant to abiotic and biotic degradation, even in a soil environment.

Acacia mangium is a fast-growing tree species. It is mainly planted in large monocultures for pulpwood in South-East Asia. Root rot has become the most economically damaging disease of this species with high tree mortality rates observed during second and third rotations. Two main types of root rots have been found in A. mangium, viz. brown root-rot and red-root disease caused by Phellinus spp. and Ganoderma spp., respectively. To assess the future management options for root rot of A. mangium, we review past and current disease-management strategies for root rot in different temperate and tropical industrial tree crops. The efficacies of a wide range of silvicultural, chemical and biological options are detailed, and their potential utilization in managing root rot of A. mangium is discussed. We conclude that the current gaps in knowledge regarding identification, biology and disease epidemiology of the root-rot pathogens will need to be addressed so that effective management options can be developed.

Decades of deforestation and unsustainable land use have created large expanses of degraded lands across Central America. Reforestation may offer one means of mitigating these processes of degradation while sustaining resident human communities. However, a lack of information regarding tree species performance has been identified as an important limitation on the success and adoption of diversified reforestation strategies. We analyzed the initial growth of 22 native and 2 exotic tree species planted at three sites across a precipitation gradient in the Republic of Panama (1100-2200 mm year À1 ), and identify promising species for use in forest restoration, timber production and on-farm systems.

The role of different plantation tree species in soil nutrient cycling is of great importance for the restoration of degraded lands. The objective of the present study was to evaluate the potential of N-fixing and non-N-fixing tree species to recuperate degraded land in southern China. The soil properties and N transformations in six forest types (two N-fixing plantations, three non-N-fixing plantations and a secondary shrubland) established in 1984 were compared. The N-fixing forests had 40–50% higher soil organic matter and 20–50% higher total nitrogen concentration in the 0–5 cm soils than the non-N-fixing forests. Soil inorganic N was highest under the secondary shrubland. The N-fixing Acacia auriculiformis plantation had the highest soil available P. There were no significant differences in soil N mineralization and nitrification among the forest types, but seasonal variation in these N processes was highly significant. In the rainy season, the rates of N mineralization (7.41–11.3 kg N ha−1 month−1) were similar to values found in regional climax forests, indicating that soil N availability has been well recovered in these forest types. These results suggest that N-fixing species, particularly Acacia mangium, are more efficient in re-establishing the C and N cycling processes in degraded land in southern China. Moreover, the N-fixing species A. auriculiformis performed better than other species in improving soil P availability.

Water use of Acacia mangium trees grown in plantations was measured by a heat balance method in two stands that largely differed in tree density. Tree sap flow was closely coupled to climatic drivers and responded with minimal time delay. Using no time shift, sap flow rate could be tightly fitted to a simple equation that combined a parabolic response to radiation and an inverse linear response to air humidity. On the contrary, the analysis of canopy conductance showed no meaningful response to either individual or combined microclimatic variables. No indication of water deficit was observed, though the measurement period was during the dry period of the year. The measurements indicate a minimal diurnal use of water stored in plant tissues. The difference in tree water use from the two studied stands was effectively scaled by tree sapwood area. Canopy transpiration of the densest stand reached in average 3.9 mm d Ϫ1 compared with 2.7 mm d Ϫ1 for the stand representing the average conditions in the catchment. ᭧

Species of Ceratocystis are well-known wound related pathogens of many tree species, including commercially planted Acacia spp. Recently, several Ceratocystis isolates were collected from wilting A. mangium in plantations in Indonesia. The aim of this study was to identify these Ceratocystis isolates and to investigate their ability to cause disease on two plantation-grown Acacia spp. using greenhouse and field inoculation experiments. For identification, morphological characteristics and comparisons of DNA sequence data for the ITS, β-tubulin and TEF 1-α gene regions, was used. Ceratocystis isolates were identified as C. manginecans, a serious pathogen of mango trees in Oman and Pakistan and a previously undescribed species, described here as C. acaciivora sp. nov. Both fungi produced significant lesions in inoculation experiments on A. mangium and A. crassicarpa, however, C. acaciivora was most pathogenic suggesting that this fungus is the primary cause of the death of trees under natural conditions.

Two consecutive years of investigation on soil surface features, surface runoff and soil detachment within 1-m 2 microplots on 40% slope highlighted the effects of land-use change, vegetation cover and biological activity on the water pathways in Northern Vietnam. Three replicate plots were set up on each of five land-uses: cassava (CAS), grass fodder of Bracharia ruziziensis (BRA), a 3-year old fallow (FAL), tree stands of Acacia mangium and Venicia montana (FOR), and a fallow with regrowth of Eucalyptus regularly cut (EUC).

Plants are frequently moved around the world, creating new regional landscapes and environmental imaginaries. Building on previous work in environmental history and geography, we develop a three-part approach to analyzing plant movements and apply it to trees from the Acacia genus (sens. lat.) exchanged between Australia and the rest of the world. First, we investigate the agents, circuits, and frequencies of acacia movements, including transoceanic transfers, regional diffusion, and ecological dispersal. Second, we trace bundles of knowledge or technology that accompany the acacias, highlighting how they help shape regional biogeographies. Finally, we analyze how different societies, with distinct economies, politics, and environmental sensibilities, receive introduced plants. This approach allows us to see transferred plants as active agents in region-forming processes, and to avoid normative tropes like 'miracle plants' or 'alien invasives'. The highlighted species include Acacia colei, Acacia melanoxylon, Acacia mearnsii, Acacia farnesiana, Acacia nilotica, Acacia mangium, and their close relatives.

To elucidate whether dipterocarp species, dominant late-successional species of tropical forests in Southeast Asia, actually have a disadvantage when planted on open site in terms of their photosynthetic characteristics, we investigated photosynthesis in dipterocarp seedlings planted in the open on degraded sandy soils in southern Thailand. These species were compared with seedlings of Acacia mangium Willd., a fast-growing tropical leguminous tree, which is often planted on degraded open site in Southeast Asia. The dipterocarp seedlings had an irradiance-saturated net photosynthetic rate (P N ), stomatal conductance (g s ), carboxylation efficiency, and photosynthetic capacity comparable to or superior to those of A. mangium. In particular, seedlings of Dipterocarpus obtusifolius Teijsm. ex Miq. showed an irradiance-saturated P N of 21 µmol m -2 s -1 , a value higher than any previously reported for a dipterocarp species, accompanied by high g s (0.7 mol m -2 s -1 ) and high photosynthetic capacity. Thus dipterocarp species do not necessarily have a disadvantage in terms of their photosynthetic characteristics on open sites with degraded sandy soils. Abbrevations: C i -internal CO 2 concentration; Chl -chlorophyll; g s -stomatal conductance; P N -net photosynthetic rate; PPFDphotosynthetic photon flux density; PS2 -photosystem 2; R D -dark respiration rate.

Plant regeneration of Acacia mangium was achieved through organogenesis in callus cultures. Calli were induced from five types of explants (embryo axes and cotyledons of mature zygotic embryos as well as leaflets, petioles and stems of seedlings) of A. mangium on MS (Murashige and Skoog, 1962) basal medium containing 9.05 µM 2,4dichlorophenoxyacetic acid (2,4-D) and 13.95 µM kinetin (KT). Green or green purple compact nodules containing clusters of meristematic centers were induced in these calli after transfer to MS basal medium containing 1.14-22.75 µM thidiazuron (TDZ) and 1.43-2.86 µM indole-3-acetic acid (IAA). A combination of 4.55 µM TDZ and 1.43 µM IAA promoted the highest percentage of calli to form nodules, in 8-11% of calli derived from cotyledons, embryo axes, leaflets or petiole and in 4% of calli derived from stems. Twenty-two percent of the nodules formed adventitious shoots on MS basal medium containing 0.045 µM TDZ. Shoots were elongated on MS medium containing 0.045 µM TDZ supplemented with 7.22 µM gibberellic acid. The medium containing 10.75 µM NAA and 2.33 µM KT promoted rooting of 10% of the elongated shoots. Plantlets grew up well in the green house.

Litter decomposition and nitrogen mineralization were investigated in subtropical plantation forests in southern China. The CO 2-C release from incubated litter and the forest floor of Acacia mangium, Acacia auriculaeformis, Eucalyptus citriodora, Pinus elliotii and Schima superba stands were used to estimate relative rates of litter decomposition. Decomposition was not positively correlated with litter nitrogen. E. citridora litter decomposed most rapidly and A. mangium litter most slowly, both with and without the addition of exotic nitrogen. Aerobic incubation and intact soil core incubation at 30 • C over a period of 30 days were used to assess nitrogen mineralization of six forest soils. Although there were differences in results obtained using the two methods, patterns between legume and non-legume species were the same regardless of method. All soils had pH values below 4.5, but this did not prevent nitrification. The dominant form of mineral nitrogen was nitrate for legume species and ammonium for non-legume species. The nitrogen mineralization potential was highest for soils in which legumes were growing.

Genetic diversity in the nuclear genome of Acacia mangium was estimated using 57 anonymous RFLP loci for 10 individuals from each of 10 natural populations representing the geographical range of the species. The level of genetic diversity varied significantly among the populations, ranging from HE=0.01 on the island of Ceram to HE=0.21 in Muting, New Guinea. The small, geographically isolated

Genomic DNA methylation was analyzed in Acacia mangium Willd. microshoots micropropagated in vitro from juvenile and mature explants, and in relation to leaf morphology of the microshoots, which is considered a phase change indicator. Based on high performance liquid chromatography (HPLC) analyses, we found more DNA methylation in microshoots exhibiting juvenile leaf morphology (22.4%) than in microshoots of the mature phyllode morphological type (20.7%), irrespective of the age of the source material. Overall, the degree of DNA methylation in A. mangium microshoots was consistent with values reported for other angiosperms. Complementary investigations based on methylation sensitive amplification polymorphism (MSAP) techniques established that, of 1204 fragments revealed by the different primer pairs used, 49 (i.e., 4.08%) were derived from C 5m CGG methylated sites. Three of these C 5m CGG sites were exclusive to the juvenile plant material, and three sites were exclusive to the mature source. No fragments were associated specifically with leaf morphology, rather than with plant age. Thus, although the two age classes could not be distinguished based on a quantitative HPLC measure of DNA methylation, qualitative differences existed, as demonstrated by the six age-specific markers identified by MSAP. The reliability of the MSAP data was confirmed on a larger sample of juvenile plant material, which suggested that the total of six methylation markers detected is probably an underestimation of the age-related differences in DNA methylation that may exist between juvenile and mature plant materials.

To investigate soil amelioration effects by older tropical fast-wood plantations, we examined the fine litterfall and accompanying nutrient flux of a 20-year-old Acacia mangium site over 3 years under a wet tropical climate in Sabah, Malaysia. The litterfall of a Swietenia macrophylla site and an Araucaria cunninghamii site was also examined for comparison. Annual nitrogen (N) flux through litterfall (kg N ha−1) was larger in A. mangium (207–223) than in S. macrophylla (126–153) or A. cunninghamii (72–94), whereas annual phosphorus (P) flux through litterfall (kg P ha−1) was considerably smaller in A. mangium (2.7–3.4) than in S. macrophylla (7.5–15.6) or A. cunninghamii (7.8–9.2). N flux through litterfall, forest floor N, and N concentration in topsoil (0–5 cm) were in the order of A. mangium > S. macrophylla > A. cunninghamii, but other element fluxes were not related to concentrations in soils. Our findings suggest that topsoil N increased because of a large N flux from litterfall. We conclude that these plantation trees, including A. mangium have the potential to produce a N flux in litterfall for the rapid return of organic N to soils larger than or equivalent to that in adjacent primary forests. However, the litterfall of a single species may lead to deficits of a particular element and cause nutrient imbalances. Using a mixture of fertilizer tree species or applying mixed litter might be a better solution.

We investigated spatial structures of N 2 O, CO 2 , and CH 4 fluxes during a relatively dry season in an Acacia mangium plantation stand in Sumatra, Indonesia. The fluxes and soil properties were measured at 1-m intervals in a 1 Â 30-m plot (62 grid points) and at 10-m intervals in a 40 Â 100-m plot (55 grid points) at different topographical positions of the upper plateau, slope, and valley bottom in the plantation. Spatial structures of each gas flux and soil property were identified using geostatistical analysis. The means (AESD) of N 2 O, CO 2 , and CH 4 fluxes in the 10-m grids were 0.54 (AE0.33) mg N m À2 d À1 , 2.81 (AE0.71) g C m À2 d À1 , and À0.84 (AE0.33) mg C m À2 d À1 , respectively. This suggests that A. mangium soils function as a larger source of N 2 O than natural forest soils in the adjacent province on Sumatra during the relatively dry season, while CO 2 and CH 4 emissions from the A. mangium soils were less than or consistent with those in the natural forest soils. Multiple spatial dependence of N 2 O fluxes within 3.2 m (1-m grids) and 35.0 m (10-m grids), and CO 2 fluxes within 1.8 m (1-m grids) and over 65 m (10-m grids) was detected. From the relationship among N 2 O and CO 2 gas fluxes, soil properties, and topographic elements, we suggest that the multiple spatial structures of N 2 O and CO 2 fluxes are mainly associated with soil resources such as readily mineralizable carbon and nitrogen in a relatively dry season. The soil resource distributions were probably controlled by the meso-and microtopography. Meanwhile, CH 4 fluxes were spatially independent in the A. mangium soils, and the water-filled pore space appeared to mainly control the spatial distribution of these fluxes.

Site preparation methods used in reforestation of Imperuta cylindricu grasslands were studied in South Kalimantan, Indonesia. In the first trial the effects of strip plowing and complete plowing on the performance of Acacia nuzngium were compared. In the second trial the effects of complete plowing, herbicide treatment and fertilization (NPK) were compared with four tree species commonly used in Zmperutu grassland reforestation. Complete plowing resulted in threefold volume increment of Acacia mungium compared with strip cultivation. Coverage and height of I. cylindrica were lower in plots treated with complete plowing. Complete plowing with initial fertilization was the most effective method for stand establishment for Gmefina arborea, Puruseriunrhes fulcatariu and Acacia rnangium. Swietenia mucrophylla did not respond to the treatments. The response to the treatments was clearest with Puruseriunthesfalcaturia. The highest mean annual volume increment estimates at the age of 36 months were 9.5 m3, 31.4 m3, 36.7 m3 and 0.5 m3 for G. urboreu, P. falcutaria, A. mungium and S. mucrophyllu, respectively. Intensive mechanical site preparation and fertilization are recommended in I. cylina'rica grassland reforestation, as they clearly speed up the initial growth of trees. Strip treatments must not be used in grasslands. Further research on the effects of fertilization is needed.

Some tropical N2-fixing trees exhibit specific characteristics for phosphorus (P) acquisition and utilisation that contrast with the large nitrogen (N) fluxes in their litterfall. To investigate differences in N and P cycling in N2-fixing plantations, litterfall and fresh leaf quality of a N2-fixing Acacia mangium plantation were compared with that of a non-N2-fixing Swietenia macrophylla plantation and a coniferous Araucaria cunninghamii plantation. The N concentration in the A. mangium litterfall was higher than that in the litterfall of the two other species, whereas the P concentration in the A. mangium leaf litterfall was 0.16 mg g–1, which was only 12–22% of that of the other species. The P concentration in the reproductive parts of A. mangium was markedly higher (16.1 mg g–1) than those in the other fractions. The N:P ratio was higher in the leaf fall (81) compared to the fresh leaves (29) of A. mangium, in contrast to the N:P ratios in the leaf samples of the other two species. An analysis of a global litterfall dataset of tropical plantations indicated that N:P ratios in litterfall were significantly higher in N2-fixers than in non-N2-fixers, and those of A. mangium were high among species in the N2-fixer group. These results indicated that A. mangium efficiently retranslocated P in contrast to very large N cycling, under field conditions. These differences may be related to other physiological characteristics of A. mangium.

An introduced plantation tree species, Acacia mangium Willd., is becoming invasive in the Brunei region of Borneo. To examine its invasive potential, a greenhouse, additive series experiment (target-neighbour) involving seedlings of A. mangium and those of a common native heath-forest (kerangas), Melastoma beccarianum Cogn. was carried out under low and high light regimes in intra-and interspecific combinations over a 6-month period. Significant variations in growth parameters (other than biomass allocation patterns) existed amongst seedlings from different treatments. A major part of this variation in growth could be attributed to the main factors of target species, neighbour species, and competition (seedling density). For the growth variables examined, the target-species response was not consistent across light regimes. Under high light conditions, Acacia was the better competitor; the Lotka-Volterra competition coefficient effect of Melastoma on Acacia was lower (a=0.30) than the effect of Acacia on Melastoma (b=0.54). However, the reverse occurred under low light conditions with Melastoma gaining the upper hand (a=1.45 and b=0.44). These results show that light (and hence disturbance) can strongly influence the pattern and intensity of both intra-and interspecific competition between invasive and local flora species. Relatively intact forest is unlikely to be invaded by Acacia trees (as they are poor competitors under this scenario). On the other hand, the Acacia trees can easily invade disturbed forests, especially those prone to recurring drought and fire, and over time convert the habitats to nearly monospecific stands, as is presently being observed in Brunei.

This manuscript focuses on the effects of land-use change and earthworm activities on the dynamics of dissolved nutrients (carbon and mineral nitrogen) in a steep slope ecosystem in Northern Vietnam. We investigated the properties of soil aggregates (casts and surrounding soils) sampled in different agrosystems: a plantation of Bracharia ruzziziensis (BRA), a fallow (FAL) and a plantation of Acacia mangium and Venicia montana (FOR), following a cultivation of cassava (CAS), and a fallow after a forest of Eucalyptus (EUC). Soil physical, chemical and biological properties were determined on the sampling date and dissolved organic C (DOC), and mineral N (N min) contents were followed during a 21-day incubation period. CAS, BRA and FOR were characterised by a high rate of N mineralisation, followed by a rapid loss of N min. Conversely, FAL and EUC were more interesting in terms of soil fertility because these systems had higher soil N min content that could become available to plants. Lost of C through DOC leaching was very low with values ever less than 0.5% of the total soil C content. The greatest lost of C through leaching was in FAL, EUC and FOR. The impacts of earthworms on the soil seemed site-specific. The protection of organic matter in earthworm casts varied with the initial substrate soil and agroecosystem management. Casts were characterised by greater enzymatic activities, except for alkaline phosphatase, than the surrounding soil. While SOM mineralisation was not affected in casts collected in FAL, EUC and FOR, the leaching of N min was increased over the surrounding soil. Conversely, mineralisation of SOM and nitrification activity were less in BRA-casts than in the surrounding soil, causing a greater retention of N min in soil. While the DOC leached from casts increased in BRA, it was reduced in FAL and was similar in the other sites. Our study indicates that while land-use change occurred only 3 years ago, the extent of leaching was mostly regulated by the type of agroecosystem and by earthworm activities.

The aim of our work was to assess the growth and mineral nutrition of salt stressed Acacia auriculiformis A. Cunn. ex Benth. and Acacia mangium Willd. seedlings inoculated with a combination of selected microsymbionts (bradyrhizobia and mycorrhizal fungi). Plants were grown in greenhouse conditions in non-sterile soil, irrigated with a saline nutrient solution (0, 50 and 100 mM NaCl). The inoculation combinations consisted of the Bradyrhizobium strain Aust 13c for A. mangium and Aust 11c for A. auriculiformis, an arbuscular mycorrhizal fungus (Glomus intraradices, DAOM 181602) and an ectomycorrhizal fungus (Pisolithus albus, strain COI 007). The inoculation treatments were designed to identify the symbionts that might improve the salt tolerance of both Acacia species. The main effect of salinity was reduced tree growth in both acacias. However, it appeared that, compared with controls, both rhizobial and mycorrhizal inoculation improved the growth of the salt-stressed plants, while inoculation with the ectomycorrhizal fungus strain appeared to have a small effect on their growth and mineral nutrition levels. Endomycorrhizal inoculation combined with rhizobial inoculation usually gave good results. Analysis of foliar proline accumulation confirmed that dual inoculation gave the trees better tolerance to salt stress and suggested that the use of this dual inoculum might be beneficial for inoculation of both Acacia species in soils with moderate salt constraints.

Somatic embryogenesis and whole plant regeneration were achieved in callus cultures derived from immature zygotic embryos of Acacia mangium. Embryogenic callus was induced on MS medium containing combinations of TDZ (1-2 mg/l), IAA (0.25-2 mg/l) and a mixture of amino acids. Globular embryos developed on embryogenic callus cultured on the induction medium. Nearly 42% of embryogenic cultures with globular embryos produced torpedo-and cotyledonary-stage embryos by a two-step maturation phase. The first stage occurred on 1/2-strength MS basal medium containing 30 g/l sucrose and 5 mg/l GA 3 followed by the second stage on 1/2-strength MS basal medium containing 50 g/l sucrose. Of the cotyledonarystage somatic embryos, 11% germinated into seedlings that could be successfully transferred to pots. Lightand scanning electron microscopy showed that the somatic embryos originated from single cells of the embryogenic callus. Further, a single cell layer could be detected beneath the developing somatic embryos that appeared to be a demarcation layer isolating the somatic proembryonic structure from the rest of the maternal callus. A suspensor-like structure connected the globular embryos to the demarcation layer. This is the first successful report of plant regeneration through somatic embryogenesis for this economically important tropical forest species. Keywords Acacia mangium 7 Somatic embryogenesis 7 Regeneration 7 Thidiazuron Abbreviations Asn L-Asparagine monohydrate 7 6-BA 6-Benzylaminopurine 7 CH Casein enzymatic hydrolysate 7 GA 3 Gibberellic acid 7 Gln L-Glutamine 7 IAA Indole-3-acetic acid 7 KT Kinetin 7 MS Murashige and Skoog (1962) 7 NAA a-Naphthaleneacetic acid 7 Pro L-Proline 7 TDZ 1-Phenyl-3-(1,2,3-thiadiazol-5-yl) urea (thidiazuron) 7 Vc Vitamin C (L-ascorbic acid)

Should policymakers -or anyone else -care about millions of ha of Imperata grasslands? The answer depends on the balance between costs of conversion to other uses and the net benefits produced in economic growth, poverty alleviation, and protection of the environment. The first section on Imperata economics sets up the analytical framework to address this question and draws on the wider development economics literature to consider whether growth and poverty alleviation are conflicting or complementary objectives. Although evidence is limited, it suggests smallholder-based agroforestry could provide the same economic growth with greater poverty alleviation than large-scale forestry estates. There is, however, no substitute for project appraisal for specific settings. The second section on lmperata policy reviews whether policy distortions and market failures provide a sufficient rationale for direct policy intervention to promote tree planting on Imperata grasslands. Estimates of imputed values of carbon sequestration to alleviate global wanning are presented for Acacia mangium and rubber agroforestry. The conclusion summarizes the policy research agenda and examines the desirability and feasibility of policy intervention to promote carbon sequestration through Imperata grassland conversion to tree-based systems.

An incubation experiment was conducted to examine the effects of the phosphorus (P) application on nitrous oxide (N2O) and nitric oxide (NO) emissions from soils of an Acacia mangium plantation in Indonesia. The soils were incubated with and without the addition of P (Ca[H2PO4]2; 2 mg P g soil)−1) after adjusting the water-filled pore space (WFPS) to 75% or 100%. The P addition increased N2O emissions under both WFPS conditions and NO emissions at 75% WFPS. Some possible mechanisms are considered. First, the P addition stimulated nitrogen (N) cycling, and N used for nitrification and/or denitrification also increased. Second, the P addition could have relieved the P shortage for nitrifying and/or denitrifying bacteria, producing N2O and NO. Our results suggest that the application of P fertilizer has the potential to stimulate N2O and NO emissions from Acacia mangium plantations, at least when soils are under relatively wet conditions.

Agroforestry, the purposeful growing of trees and crops in interacting combinations, began to attain prominence in the late 1970s, when the international scientific community embraced its potentials in the tropics and recognized it as a practice in search of science. During the 1990s, the relevance of agroforestry for solving problems related to deterioration of family farms, increased soil erosion, surface and ground water pollution, and decreased biodiversity was recognized in the industrialized nations too. Thus, agroforestry is now receiving increasing attention as a sustainable land-management option the world over because of its ecological, economic, and social attributes. Consequently, the knowledge-base of agroforestry is being expanded at a rapid rate as illustrated by the increasing number and quality of scientific publications of various forms on different aspects of agroforestry.

This study compares the edaphic macroarthropod communities from experimental plantations of Acacia mangium and Eucalyptus grandis, both 7 years old, and from the primary forest, all located on the table-land region in the state of Espirito Santo (Brazil). Most of the taxonomic groups analyzed reach densities as high, or higher, in the plantations as in the primary forest. Four points however differentiate the communities of both plantations from that of the forest: the absence of Diplura and Pseudoscorpionida; the lower relative abundance of ants; the dominance of some non-social arthropods; and the concentration of a great percentage of macroarthropods in the litter layers. All these features seem to reflect a higher complexity in the decomposition subsystem of the primary forest, which is expected since it is a natural ecosystem. Regarding agroecosystems, the community under A. mangium shows a lower seasonal variation of total densities and a higher density of Blattaria, Isopoda, Coleopteran larvae and Lepidopteran larvae. These differences are apparently a consequence of the greater quantity of leaf litter, rich in nutrients, accumulated on the soil in this plantation. Therefore, both plantations create a propitious environment for macroarthropod communities. But A. mangium seems to provide better conditions to the soil communities, and thus it seems to be an important alternative to conciliate the wood production and the recuperation of edaphic communities in areas surrounding the remnants of the Atlantic forest.

The majority of plant expressed sequence tags (ESTs) available in the public databases are from nonwoody species such as Arabidopsis, maize, soybean, and rice, with the exception of the model tree species, Populus. In this study, we report the first EST database constructed from the commercially important tree species Acacia. ESTs were generated from pooled RNA extracted from the mature, intermediate, and young inner bark tissues of an Acacia auriculiformis x Acacia mangium hybrid. Finally, 3,182 high-quality ESTs were analyzed representing a total of 1,982 unique transcripts (663 contigs and 1,319 singletons) for the inner bark cDNA library. A total of 1,053 unigenes (1,750 ESTs) showed similarities with protein sequences in public database where 867 were significant matches (E value≤e −10 ). Further analysis performed on unigenes with significant matches and known functions identified 231 genes including genes involved in cellulose, lignin, and hemicellulose biosynthesis. For cDNA library validation, quantitative real-time RT-PCR was performed to study the expression levels of the cellulose and lignin genes identified from this EST database in the phloem tissue of A. mangium, A. auriculiformis, and A. auriculiformis x A. mangium hybrid. All the seven candidate genes were expressed in all the individuals studied confirming the dependability of the EST database. The cDNA library and the EST database constructed are valuable resources for forest tree research aiming towards understanding the genetic control of wood formation and in the future endeavors to modify wood and fiber profile through marker-assisted breeding programs.

Functional compatibility between one provenance of Acacia mangium Willd seedlings and one fungal isolate of Pisolithus sp. COI 007 was evaluated in four Senegalese soils. This was measured to mycorrhizal formation, root colonization, shoot and root dry weight and mineral nutrient contents in the leaves of A. mangium seedlings. Mycorrhizal formation occurred on A. mangium in all the soils. However, percentage of root colonization of A. mangium by Pisolithus sp. varied from 90% to 10%. It reached no more than 10% in soil having the highest available P (Olsen P 20 ppm) and at least 60% in soils containing low available P (from Olsen P 2.3±6.8 ppm). Shoot and root dry weight of inoculated plants signi®cantly increased as a consequence. P, N, K, Ca, Mg, Na, S, Cu and Zn concentrations in leaves of A. mangium contributed signi®cantly to inoculated plant growth in soils having the lower available P. These results are discussed in the light of management techniques of multiple types of symbiotical microorganisms in nursery and ®eld conditions. #

Acacia mangium and Paraserianthes talcataria are leguminous tree species widely grown for timber in Indonesia and other tropical countries, yet little is known about the identity of their rhizobial symbionts. Polymerase chain reaction-restriction fragment length polymorphism-single-strand conformational polymorphism (PRS) analysis of lhe 165 rRNA gene was used along with sequencing to assess the diversity of 57 rhizobia isolated from nodules of A. mangium and P. falctaria in Indonesia. In total, 26 rhizobia isolated from A. mangium were analysed by PRS and sequencing. The PRS patterns indicated that 12 (46%) clustered with Bradyrhizobium elkanii, 13 (50%) with B. lianoningenseliaponicum and one (4%) wilh Mesorhizobium /ofi. Thirty-one isolates were analysed from P. falcataria: five (16%) clustered with B. elkanii and 26 (84%) with B. lianoningensel japonicum. These results were confirmed by phylogenetic analysis of sequences. Intraspecific diversity of the 165 rRNA genes from rhizobia nodulating A. mangium and P. falcataria revealed by PRS was low, only one genotype was found within the isolates that cfustered with E| elkan.ii and two within the B. liaoningenseljaponicum group. These Bradyrhizobium species are apparently ubiquitous throughout the Indonesian archipelago and it is clear why the two tree species are able to successfully establish outside their native range without the need for inoculation with indigenous rhizobia.

This manuscript focuses on the effects of above-ground earthworm casts on water runoff and soil erosion in steep-slope ecosystems in Northern Vietnam. We investigated the effects of Amynthas khami, an anecic species producing above-ground casts of prominent size, on water infiltration and soil detachment along a land-use intensification gradient: a cultivation of cassava (Mahinot esculenta; CAS), a plantation of Bracharia (Bracharia ruzziziensis; BRA), a fallow (FAL), a fallow after a forest of Eucalyptus sp. (EUC) and a plantation of trees (Acacia mangium and Venicia Montana; FOR). Two scales of studies were considered: (i) at the structure scale (cm 2 ), a water runoff simulation was used to differentiate the effects of casts, free biogenic aggregates that previously belong to casts, and free physicogenic aggregates; (ii) at the station levels, 1-m 2 plots were used to determine runoff and soil detachment rates during the rainy season in 2005.

O objetivo do estudo foi avaliar os efeitos de plantios de Acacia mangium, localizados no cerrado em Roraima, sobre o carbono orgânico e biomassa microbiana do solo. Foram realizadas amostragens de solo nas profundidades de 0-20 cm e 20-40 cm em dois plantios de A. mangium com cerca de cinco anos de idade, e em duas áreas de Cerrado nativo consideradas referência. Um dos plantios de A. mangium (localizado na Fazenda Cigolina) correspondeu a um plantio homogêneo (espaçamento de 3,6 m entre linhas e 2,0 m entre plantas) enquanto que o outro (localizado no Campo Experimental Água Boa - CEAB) correspondeu a um plantio em faixas com duas linhas de plantio (espaçamento de 6 m entre linhas, 2,5 m entre plantas e cerca de 30 m entre faixas). As amostras de solo foram analisadas quanto ao carbono orgânico, carbono da biomassa microbiana, respiração basal do solo e quociente metabólico, além de atributos químicos de fertilidade. Foi verificado que os plantios de A. mangium não proporcionaram ...

Fungal sporocarps and cultures associated with signs and symptoms of root-rot disease were collected from Acacia mangium and other tropical hardwood species. The collections were identified by either morphological characters and/or by phylogenetic analysis based on DNA sequences as Ganoderma philippii, G. mastoporum, G. aff. steyaertanum, G. australe and Amauroderma rugosum. Phylogenetic analysis unequivocally placed in the G. philippii clade four sequences amplified from A. mangium root and butt tissue showing clear signs of red root-rot disease (roots are covered by a red rhizomorphic skin). Whereas G. philippii was the most frequently encountered fungal species in A. mangium with red root-rot disease, this study indicates that other fungal species related to G. mastoporum may cause root-rot disease with very similar symptoms. An isolate (FRIM 138) that had caused red root-rot disease in artificial inoculations carried out before this study and was presumed to be G. philippii, is here determined to be closely related to G. mastoporum, G. cupreum and G. sinense. A Ganoderma species associated with a yellow-brown root-rot disease killing trees in an A. mangium plantation in Central Java, previously identified as G. lucidum, is shown by phylogenetic analysis to be closely related to G. steyaertanum, though some morphological characters vary from the original description of that species.

Field trials testing a total of 27 clones of the interspecific hybrid Acacia mangium × A. auriculiformis and seedling controls of the parental species were established at Ba Vi and Yen Thanh in the north of Vietnam and Long Thanh in the south. At both Ba Vi and Yen Thanh there were significant (P < 0.001) differences in height and diameter at breast height (DBH) among 22 tested clones at 4 years. At Long Thanh, twelve hybrid clones did not differ significantly in DBH at age 3 years, but did (P < 0.001) at age 5 years. At the two northern sites the acacia hybrid clones had significantly greater DBH than control seedlots of the parental species. At Long Thanh, DBH of the hybrid clones and A. mangium was similar, with a genetically improved seedlot of A. mangium displaying the best DBH. Mean wood basic density at breast height of the acacia hybrid clones was 539 kg m−3 at Yen Thanh at age 8 years, and 473 kg m−3 at Long Thanh at age 5 years; density for A. mangium at Long Thanh was only slightly lower than the hybrid clones at 461 kg m−3. Linear regressions of Pilodyn penetration (PP) at breast height on wood basic density explained 60% of the variance in density of treatments (clones and control seedlots) at Yen Thanh and 36% at Long Thanh. There were significant differences between hybrid clones in PP at all three trial sites. Clonal DBH performance was not strongly correlated across the three trial sites; Pearson correlations of clone mean DBH between pairs of sites ranged from −0.47 to 0.20. Clonal rankings for PP were more stable, with Pearson correlations between pairs of sites ranging from r = 0.71 to 0.78.

Infection of heartwood by decay fungi (heartrot) is a concern for growers of Acacia mangium for solid-wood products as the incidence can be high in some regions of Indonesia. Variation of heartrot incidence for different provenances of A. mangium was determined using two field trials in Sumatra, Indonesia. In a Riau Province trial of 21 provenances, the effect of provenance was statistically significant for natural heartrot incidence, which ranged from 1.6% to 27.2%. In a smaller trial using artificial inoculation in South Sumatra, heartwood infection incidence ranged from 39.4% to 70.8% across six provenances and both wound type and provenance were statistically significant factors. There was also significant variation in sapwood infection length related to provenance. Wood extractives (yield, total phenols, protein-precipitable tannin and 2,3-trans-3,4′,7,8-tetrahydroxyflavanone) were quantified from a subsample of trees for each trial. However, no significant differences in extractive concentration were detectable according to provenance and evidence for a relationship between heartwood extractives and heartrot incidence was generally poor. While further studies need to be completed to establish the basis for heartrot incidence, results from these trials allow for recommendations on provenance selection to reduce heartrot incidence and provide information for further genetic selection programmes.L'infection du bois de cœur par des champignons de pourriture (pourriture de cœur) est un problème pour les producteurs de bois d’Acacia mangium dans certaines régions d'Indonésie où l'incidence est forte. La variation de l'incidence de la pourriture de cœur entre provenances d’Acacia mangium a étéétudiée dans deux dispositifs de terrain à Sumatra, Indonésie. Dans l'essai de la provenance de Riau portant sur 21 provenances, un effet significatif de la provenance a été montré sur l'incidence naturelle de la pourriture de cœur, variant de 1.6 à 27.2%. Dans un essai plus petit dans le sud de Sumatra, où des inoculations artificielles ont été pratiquées, l'incidence de l'infection du bois de cœur a été comprise entre 39.4 et 70.8% entre 6 provenances, un effet significatif étant montréà la fois pour le type de blessure et la provenance. Un effet significatif de la provenance a également été observé sur la longueur d'infection de l'aubier. Les extraits du bois (rendement, phénols totaux, tannins précipitables par les protéines, 2,3-trans-3,4′,7,8-tetrahydroxyflavanone) ont été quantifiés dans un sous-échantillon d'arbres de chaque essai. Aucune différence significative dans la concentration d'extraits n'a pu être détectée entre provenances, et l'existence d'une relation entre extraits du bois de cœur et incidence de la pourriture est généralement peu confortée. Des études complémentaires restent nécessaires pour établir les facteurs d'incidence de la pourriture de cœur mais les résultats de ces essais permettent dès maintenant de faire des recommandations pour la sélection des provenances et apportent des informations pour les programmes d'amélioration génétique en vue d'une diminution de l'incidence de la pourriture de bois de cœur.Acacia mangium wird in einigen Regionen Indonesiens stark von Kernfäulen befallen. In zwei Provenienzversuchen in Sumatra wurde das Auftreten von Kernfäule für verschiedene Provenienzen von A. mangium bestimmt. In einem Experiment in der Provinz Riau, welches 21 Provenienzen umfasst, wirkte sich die Provenienz signifikant auf das natürliche Vorkommen von Kernfäulen aus, wobei der Befall von 1.6 bis 27.2% variierte. In einem kleineren Versuch mit künstlicher Inokulation an 6 Provenienzen in Südsumatra lagen die Infektionsraten im Kernholz zwischen 39.4 und 70.8%. Sowohl die Art der Verletzung bei der Inokulation als auch die Provenienz erwiesen sich als statistisch signifikante Faktoren. Auch die Länge der Splintholzinfektion variierte signifikant in Abhängigkeit von der Provenienz. Für jeden Versuch wurden von einem Teil der Bäume verschiedene Holzextraktstoffe (Extraktionsmenge, Gesamtphenole, Protein-fällbare Tannine und 2,3-trans-3,4′,7,8-tetrahydroxyflavanon) quantifiziert. Es waren jedoch keine signifikanten Konzentrationsunterschiede bei diesen Extrakten zwischen den Provenienzen vorhanden und das Vorkommen von Kernfäulen war mit den Holzextrakten nur schwach korreliert. Wenn auch die genauen Ursachen für das Auftreten von Kernfäulen noch in weiteren Untersuchungen abgeklärt werden müssen, so lassen sich aus den Ergebnissen der vorliegenden Untersuchung doch Empfehlungen für eine Provenienzwahl ableiten und die Daten bieten eine Grundlage für weitere genetische Selektionsprogramme zur Reduktion von Kernfäulen.

RESUMO -(Respostas de Acacia mangium Willd e Sclerolobium paniculatum Vogel a fungos micorrízicos arbusculares nativos provenientes de áreas degradadas pela mineração de bauxita na Amazônia). A resposta de Acacia mangium Willd (mangium) e Sclerolobium paniculatum Vogel (tachi) à inoculação de fungos micorrízicos arbusculares (FMA), oriundos de áreas em recuperação após a extração de bauxita, foi avaliada em experimento com delineamento inteiramente casualizado, com 14 tratamentos (duas espécies leguminosas e sete tipos de solo) e três repetições. Avaliou-se o número de esporos no solo, a colonização micorrízica, a matéria seca total, o P acumulado, a dependência micorrízica das mudas, e a abundância e a freqüência de espécies. O número de propágulos infectivos (NPI) foi estudado em delineamento em blocos casualizados, com oito diluições de solo inóculo, cinco repetições e uma planta isca (Brachiaria decumbens Stapf). Utilizou-se substrato da mistura de um Planossolo mais areia lavada e fosfato de rocha araxá (0,60 g/kg). O número de esporos aumentou em função do tempo de cobertura das leguminosas. A colonização micorrízica foi mais intensa no tachi. Os valores de matéria seca dessa espécie foram inferiores aos de mangium, que por sua vez extraiu em torno de seis vezes mais P do substrato. Em geral, mangium, ao contrário do tachi, foi facultativa à presença dos FMA, sugerindo sua utilização na recuperação de áreas degradadas sem inoculação prévia. Dentre as 39 espécies de FMA identificadas, Glomus macrocarpum Tul. & Tul. apresentou maior índice de abundância e freqüência (IAF) e maior NPI, destacando-se entre as espécies pioneiras, ao passo que outras apareceram apenas em estádios sucessionais mais avançados das áreas em recuperação.

The objective of this study was to evaluate the effect of leguminous fallows on methane (CH 4 ), carbon dioxide (CO 2 ), N oxides (N 2 O and NO) fluxes. We measured CH 4 , N 2 O, NO, and CO 2 fluxes from improved fallows of Inga edulis and Acacia mangium during two successive fallow periods in an old agricultural frontier on sandy soils in eastern Amazonia. Sampling for the first fallow period was done in 1996 and 1997 while that for the second fallow was done in 1999 and 2000. We observed net CH 4 uptake during majority of the sampling campaigns. We did not observe any significant difference in CH 4 flux between improved fallows and unimproved fallows (control) during either of the sampling periods (P > 0.05). We observed significantly higher uptake during the dry season relative to wet season, indicating the importance of soil water content and gas transport on CH 4 fluxes. For both wet and dry seasons, soil respiration rates (CO 2 ), N 2 O and NO fluxes were similar for improved fallow plots and the control (P > 0.05). We did not observe any significant seasonality in soil respiration or NO fluxes, but there was a significant difference in N 2 O flux between seasons (P = 0.0638). Contrary to other studies, our observations suggest that improved fallows using N-fixing trees do not appear to decrease the soil CH 4 sink and also do not seem to increase CO 2 and N-oxide emission in these sandy Amazonian soils. The result for N oxides is particularly pertinent to greenhouse gas (GHG) accounting methods that assess N 2 O emissions as a fraction of N fixation. #

Reforestation of degraded tropical sites is often hampered by soils of high acidity, high aluminum saturation, and low fertility. To evaluate the possibility of cultivating Acacia species on such soils, a study was conducted at Waiawa, HI, to test growth under conditions of (1) high acidity (primarily aluminum) and nutrient stress, and (2) no acidity stress and high nutrient availability. Twelve Acacia species, including the important native Hawaiian species Acucin koa, were established

Phenolic compounds are present at very high concentrations in the bark of Acacia mangium. These compounds are known to have strong antioxidant activity and thus different beneficial effects on human health. Phenolic compounds in bark of A. mangium were extracted and their antioxidant activities were investigated using the 1,1-diphenyl-2picrylhydrazyl (DPPH) free radical-scavenging and ferric-reducing antioxidant power (FRAP) assays. A central composite design has been employed to optimize the experimental conditions for a high total phenolic content and antioxidant activity. The desirability function approach has been employed to simultaneously optimize the three responses: total phenols, antiradical activity and FRAP. An extraction time of 90 min, liquid-solid ratio of 5, and temperature of 50 °C was predicted for the optimum experimental conditions using the desirability function. A significant linear relationship between antioxidant potency, antiradical activity and the content of phenolic compounds of bark extracts was observed. The structures of condensed tannins isolated from A. mangium were characterized by MALDI-TOF MS analyses. Condensed tannin oligomers from A. mangium were shown to be heterogeneous mixtures consisting of procyanidin and prodelphinidin structural units with polymerization degrees up to 9.

This paper describes a diagnostic system to verify interspecific hybrids between Acacia mangium and A. auriculiformis using single nucleotide polymorphism (SNP) markers. Forty-eight DNA fragments were selected based on random amplified polymorphic DNAs (RAPD) amplified across 48 individuals from each parental species, and were transformed into 44 sequence-characterized amplified region (SCAR) markers. Five SNP markers that generated species-specific alleles for each species were selected from the 28 sequenced SCARs. A multiplex single nucleotide primer extension (SNuPE) analyses of the five SNPs using 40 A. mangium, 40 A. auriculiformis and 16 Acacia hybrids showed high discrimination power. This diagnostic system, with high discriminatory ability, provides a highly reliable and fast method for identifying interspecific hybrids of A. mangium and A. auriculiformis.

This study is a comparison of the holorganic horizons (L and F) and hemiorganic horizons (A 11 and A 12 ) of 7-years-old stands of Eucalyptus grandis and Acacia mangium, in the region of the Tabuleiro Forest, in Linhares, Espírito Santo, Brazil. In the soil under A. mangium, the stocks of organic matter in the L and F horizons were higher, and the C/N ratio was lower, due to the high nitrogen content of the leaf material. The same was observed for the A horizon chemical properties: the C and nutrients concentrations of the soil fine fraction were higher under A. mangium. The comparison of the C and nutrient concentrations between the A 11 and A 12 horizons and between the aggregate fraction and fine fraction showed similar trends in both sites. In both plantations, the C and nutrient concentrations were higher in A 11 than in A 12 horizons, and the soil aggregate fraction had higher concentration of nutrients than the soil fine fraction. Nevertheless, the percentage of aggregates in the soil matrix was much higher in A. mangium than in E. grandis. These results show that in this superficially sandy soil (Argissolo Amarelo Distrófico -Ultisol), the organic matter is the most important way of keeping nutrients, and that the aggregate fraction can be the most effective way of avoiding nutrient loss to the deeper soil horizons. In this context, A. mangium provides better conditions for restoring the soil fertility and soil biodiversity, thus providing better sustainability of the cropping systems than E. grandis.