Growth, physiological responses and wood production of an Acacia auriculiformis plantation in southern Vietnam following mid-rotation thinning, application of phosphorus fertiliser and organic matter retention

Acacia auriculiformis A. Cunn. ex Benth. is an important planting tree species, but little attention has been paid to its wood properties, such as shrinkage, stiffness, strength, and basic density, which are important for use in structural and appearance-grade timber applications. Here we report the genetic variation in static bending stiffness and strength of wood in a 5½-year-old clone trial in southern Vietnam and the genotypic correlations among these traits and tree diameter, wood shrinkage, and basic density. There was significant variation in stiffness and strength among 40 randomly selected clones. Clonal repeatability (H2) was high for stiffness and moderate for strength. There was no consistent pattern of difference between heartwood and sapwood for the estimates of H2 for stiffness and strength, whereas the estimates of H2 were lower for heartwood density than for sapwood density. Diameter showed a significant negative genotypic correlation with stiffness but a nonsignificant correlation with strength. Genotypic correlations between density and stiffness, and density and strength, were positive, but only the latter was significant. Stiffness and strength were not significantly correlated with wood shrinkage. There is potential to simultaneously improve tree growth, wood basic density, and the mechanical properties of juvenile wood of this species.

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Sustainable Management of Acacia auriculiformis Plantations for Wood Production over Four Successive Rotations in South Vietnam

Forests ◽

10.3390/f11050550 ◽

2020 ◽

Vol 11 (5) ◽

pp. 550 ◽

Cited By ~ 4

Author(s):

Vu Dinh Huong ◽

E. K. Sadanandan Nambiar ◽

Nguyen Xuan Hai ◽

Kieu Manh Ha ◽

Nguyen Van Dang

Keyword(s):

Sustainable Management ◽

Management Practices ◽

Integrated Management ◽

Rural Livelihoods ◽

Acacia Auriculiformis ◽

Wood Production ◽

Short Rotation ◽

South Vietnam ◽

Forestry Sector ◽

Feasible Option

Vietnam’s forestry sector is facing rising demands for wood to support national and rural economies, and rural livelihoods. A feasible option to meet this demand is to improve productivity in the current plantation estates, especially in those owned by thousands of small growers. Growers have invested in short-rotation acacia plantations primarily for the woodchip market, but are being urged through government policies and pressured by certification bodies and some NGOs to shift to longer rotations, preferentially, for growing saw logs. In this context, we examined the productivity of an Acacia auriculiformis plantation in South Vietnam, over four successive rotations, spanning 25 years. We show that it is possible to increase and sustain wood production in the long term, by applying simple but integrated management practices, recognizing that the conservation of site resources is critical for sustainability. Practices which depleted site organic matter and nutrients lead to a hidden, but high, cumulative loss of production. Given the site and soil damaging practices prevalent in the country, it is likely that production foregone in those sites may be equivalent to the yield from one in every four or five rotations harvested. With sound management including the conservation of site resources, planting the best germplasm, appropriate stocking and judicious use of herbicide, total wood production and the proportion of saw logs (50–70% of the commercial wood at about 7 years of age) can be increased substantially. At the same time, these practices also can promote understory development and diversity in the stand. Such holistic benefits are possible without extending the rotation length and/or thinning, which are likely to raise the levels of risks for small growers, who are not covered by any insurance. Investments and support for small growers to enable higher productivity and value per unit area in their holdings, through sustainable management, would offer practical and low-risk options for the benefits of growers, processors and ecosystems.

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Relationships between net nitrogen mineralization, properties of the forest floor and mineral soil, and wood production in Pinus radiata plantations

Canadian Journal of Forest Research ◽

10.1139/x01-008 ◽

2001 ◽

Vol 31 (5) ◽

pp. 889-898 ◽

Cited By ~ 16

Author(s):

J Clive Carlyle ◽

EK Sadanandan Nambiar

Keyword(s):

Organic Matter ◽

Soil Properties ◽

Pinus Radiata ◽

N Mineralization ◽

Forest Floor ◽

Mineral Soil ◽

Soil N ◽

Wood Production ◽

Total N

We examined the relationship between net nitrogen (N) mineralization (subsequently termed N mineralization) in the forest floor and mineral soil (00.15 m) of 20 Pinus radiata D. Don plantations ranging in age from 23 to 59 years, how mineralization was influenced by soil properties, and its relationship to wood production. Forest floor properties had a narrower relative range than the same set of mineral soil properties. Total N in the litter layer was 5.09.5 g·kg1 compared with 0.232.53 g·kg1 in mineral soil. Laboratory rates of net N mineralization ranged between 1.1 and 9.7 mg·kg1·day1 in forest floor and between 0.02 and 0.53 mg·kg1·day1 in mineral soil. The range in litter lignin (35.348.0%) was especially narrow, despite the large range in stand productivity. Nitrogen mineralized in the forest floor was not correlated with any of the measured forest floor or mineral soil properties. Nitrogen mineralized per unit mineral soil N (ksn) was negatively correlated with the mineral soil N to organic phosphorus ratio (N/Po) (r2 = 0.82). In mineral soil a relationship combining N/Po and total N concentration explained 90% of the variation in N mineralized. Nitrogen mineralized in the forest floor was correlated with that mineralized in the mineral soil when expressed per unit C or N (r2 = 0.54 or 0.57, respectively). Thus, the quality of organic matter in the forest floor partly reflected the quality of organic matter in the mineral soil with respect to N mineralization. Mineralization in mineral soil dominated the net N available to the stand. For sandy soils, wood production (m3·ha1·year1) was correlated with N mineralized in the forest floor + mineral soil (r2 = 0.71). In P. radiata stands growing in southern Australia, rates of wood production per unit N mineralized and per unit rainfall appear to be substantially higher than those of a wide range of natural and planted stands in North America.

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Growth performance and lignin content of Acacia mangium Willd. and Acacia auriculiformis A. Cunn. ex Benth. under normal and stressed conditions

Journal of Forest Science ◽

10.17221/100/2015-jfs ◽

2017 ◽

Vol 63 (No. 8) ◽

pp. 381-392

Author(s):

Asif Muhammad Javed ◽

Govender Nisha Thopla ◽

Ang Lai Hoe ◽

Ratnam Wickneswari

Keyword(s):

Organic Matter ◽

Soil Temperature ◽

Growth Performance ◽

Lignin Content ◽

Acacia Mangium ◽

Water Holding Capacity ◽

Acacia Auriculiformis ◽

Fast Growing ◽

Water Holding ◽

Fast Growing Species

Acacia mangium Willdenow and Acacia auriculiformis A. Cunningham ex Bentham are fast-growing species with wide environmental adaptability. Fast-growing species which thrive in otherwise non-arable problematic soil and which hold the added advantage of improving the condition of the soil, can be used to increase production area, and, thus, are highly desired. We investigated the growth performance and lignin content under normal and stressed conditions for these Acacia mangium Willd. and Acacia auriculiformis A. Cunn. ex Benth. Normal growing conditions was represented by fertile soil, high water-holding capacity due to low soil drainage, high organic matter, low soil temperature, overall consistent rainfall and relatively milder temperatures, whilst stressed conditions were achieved with a sandy soil with low fertility, low water-holding capacity due to high drainage and low organic matter, and high soil temperature accompanied by inconsistent monthly temperature and rainfall. Growth performance under normal conditions was significantly better compared to the stressed conditions. A. mangium performed better than A. auriculiformis under the normal conditions. However A. auriculiformis performed better under stressed conditions due to better adaptability. The lignin content under normal conditions fluctuated from one DBH class to another. As for the stress conditions, A. mangium exhibited incremental increases in lignin content with increasing biomass. In contrast, lignin content in A. auriculiformis decreased with increasing biomass. The differences in performance may be attributable to both the micro- and macro-environments and adaptive differences between the two species. For growth under normal conditions, A. mangium appears to be the superior choice, whereas for problematic soils, A. auriculiformis can be recommended. However, for the selection of superior plants with a combination of desired growth rates and lower lignin content the breeding of interspecific hybrids would be a desirable approach.

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Physiological responses of the seagrass Posidonia oceanica to elevated organic matter content in sediments: An experimental assessment

Journal of Experimental Marine Biology and Ecology ◽

10.1016/j.jembe.2006.12.020 ◽

2007 ◽

Vol 344 (2) ◽

pp. 149-160 ◽

Cited By ~ 56

Author(s):

Marta Pérez ◽

Olga Invers ◽

Juan Manuel Ruiz ◽

Morten S. Frederiksen ◽

Marianne Holmer

Keyword(s):

Organic Matter ◽

Physiological Responses ◽

Organic Matter Content ◽

Posidonia Oceanica ◽

Matter Content ◽

Experimental Assessment

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Misophonia: An Evidence-Based Case Report

American Journal of Audiology ◽

10.1044/2020_aja-19-00111 ◽

2020 ◽

Vol 29 (4) ◽

pp. 685-690

Author(s):

C. S. Vanaja ◽

Miriam Soni Abigail

Keyword(s):

Quality Of Life ◽

Case Report ◽

Case History ◽

Pure Tone ◽

Physiological Responses ◽

Evidence Based ◽

Management Option ◽

Pure Tone Audiogram

Purpose Misophonia is a sound tolerance disorder condition in certain sounds that trigger intense emotional or physiological responses. While some persons may experience misophonia, a few patients suffer from misophonia. However, there is a dearth of literature on audiological assessment and management of persons with misophonia. The purpose of this report is to discuss the assessment of misophonia and highlight the management option that helped a patient with misophonia. Method A case study of a 26-year-old woman with the complaint of decreased tolerance to specific sounds affecting quality of life is reported. Audiological assessment differentiated misophonia from hyperacusis. Management included retraining counseling as well as desensitization and habituation therapy based on the principles described by P. J. Jastreboff and Jastreboff (2014). A misophonia questionnaire was administered at regular intervals to monitor the effectiveness of therapy. Results A detailed case history and audiological evaluations including pure-tone audiogram and Johnson Hyperacusis Index revealed the presence of misophonia. The patient benefitted from intervention, and the scores of the misophonia questionnaire indicated a decrease in the severity of the problem. Conclusions It is important to differentially diagnose misophonia and hyperacusis in persons with sound tolerance disorders. Retraining counseling as well as desensitization and habituation therapy can help patients who suffer from misophonia.

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