title: Chemical Characterisation of Compression Wood in Plantation Grown Pinus Radiata

authors: Nanayakkara, Bernadette

subjects: Chemistry

abstract: The primary objective of this study was to find out if changes in chemistry could be used to quantify Pinus radiata compression wood severity or degree of compression wood development. Basic chemical composition and the lignin structure was assessed for a range of different compression wood samples sourced from juvenile wood, mature wood, earlywood, latewood, branches, knots, 2-year and 1-year old Pinus radiata. Fluorescence microscopy was used as the reference method to assess the degree of compression wood development. Lignin structure of compression wood was studied by thioacidolysis, size exclusion chromatography, and thioacidolysis/31P NMR spectroscopy.
Variation in the basic chemical composition and lignin structure with compression wood severity was ascertained. Results showed that, as the severity of compression wood changed, progressively from normal through mild to severe, all chemical parameters commonly associated with compression wood changed concurrently. With increasing severity lignin and galactose levels increased while glucose and mannose levels decreased.
Lignin structural changes were also associated with changing severity of compression wood. Levels of p-hydroxyphenyl (H) releasable β-ethers increased and guaiacyl (G) releasable β-ethers decreased. Similarly, levels of uncondensed p-hydroxyphenyl units increased, while uncondensed guaiacyl units decreased. Similar proportions of condensed guaiacyl units were present in compression wood and normal wood. Similar trends in chemical composition were observed between the compression wood and related opposite wood in branches, knots and young wood of Pinus radiata.
A number of chemical parameters changed linearly with compression wood severity. They were: the amount of lignin and galactose, the galactose/glucose ratio and p-hydroxyphenyl content in lignin. Parameters based on the p-hydroxyphenyl unit content in lignin, the H/G releasable β-ether ratio, releasable p-hydroxyphenyl β-ether units and uncondensed p-hydroxyphenyl C9 units are most suitable indicators of compression wood severity as they spanned a larger range relative to the normal wood levels and were not influenced by the morphological origin of wood samples. Chemical methods for quantifying compression wood severity should focus on the detection and measurement of these parameters.
Galactan present in Pinus radiata compression wood was isolated and characterised. Structural investigation by methylation analysis and NMR spectroscopy revealed that this galactan was largely composed of (1→4)-linked β-D-galactopyranose residues. No evidence was found to indicate the presence of any branches.
Characterisation of lignin in cell wall fractions of Pinus radiata normal wood revealed that middle lamella lignin has a higher lignin content, a lower amount of releasable β-ethers and a more condensed lignin than the secondary wall lignin. Levels of releasable p-hydroxyphenyl units were not higher in middle lamella lignin.
A new method based on thioacidolysis and 31P quantitative NMR spectroscopy for estimation of the degree of lignin condensation of the phenolic and etherified C9 units in in situ wood lignin is described. Using this method it was found that phenolic C9 units in in situ lignin were considerably less condensed than etherified C9 units in both compression wood and normal wood.

text: Chemical Characterisation of Compression Wood in Plantation Grown Pinus Radiata The primary objective of this study was to find out if changes in chemistry could be used to quantify Pinus radiata compression wood severity or degree of compression wood development. Basic chemical composition and the lignin structure was assessed for a range of different compression wood samples sourced from juvenile wood, mature wood, earlywood, latewood, branches, knots, 2-year and 1-year old Pinus radiata. Fluorescence microscopy was used as the reference method to assess the degree of compression wood development. Lignin structure of compression wood was studied by thioacidolysis, size exclusion chromatography, and thioacidolysis/31P NMR spectroscopy.
Variation in the basic chemical composition and lignin structure with compression wood severity was ascertained. Results showed that, as the severity of compression wood changed, progressively from normal through mild to severe, all chemical parameters commonly associated with compression wood changed concurrently. With increasing severity lignin and galactose levels increased while glucose and mannose levels decreased.
Lignin structural changes were also associated with changing severity of compression wood. Levels of p-hydroxyphenyl (H) releasable β-ethers increased and guaiacyl (G) releasable β-ethers decreased. Similarly, levels of uncondensed p-hydroxyphenyl units increased, while uncondensed guaiacyl units decreased. Similar proportions of condensed guaiacyl units were present in compression wood and normal wood. Similar trends in chemical composition were observed between the compression wood and related opposite wood in branches, knots and young wood of Pinus radiata.
A number of chemical parameters changed linearly with compression wood severity. They were: the amount of lignin and galactose, the galactose/glucose ratio and p-hydroxyphenyl content in lignin. Parameters based on the p-hydroxyphenyl unit content in lignin, the H/G releasable β-ether ratio, releasable p-hydroxyphenyl β-ether units and uncondensed p-hydroxyphenyl C9 units are most suitable indicators of compression wood severity as they spanned a larger range relative to the normal wood levels and were not influenced by the morphological origin of wood samples. Chemical methods for quantifying compression wood severity should focus on the detection and measurement of these parameters.
Galactan present in Pinus radiata compression wood was isolated and characterised. Structural investigation by methylation analysis and NMR spectroscopy revealed that this galactan was largely composed of (1→4)-linked β-D-galactopyranose residues. No evidence was found to indicate the presence of any branches.
Characterisation of lignin in cell wall fractions of Pinus radiata normal wood revealed that middle lamella lignin has a higher lignin content, a lower amount of releasable β-ethers and a more condensed lignin than the secondary wall lignin. Levels of releasable p-hydroxyphenyl units were not higher in middle lamella lignin.
A new method based on thioacidolysis and 31P quantitative NMR spectroscopy for estimation of the degree of lignin condensation of the phenolic and etherified C9 units in in situ wood lignin is described. Using this method it was found that phenolic C9 units in in situ lignin were considerably less condensed than etherified C9 units in both compression wood and normal wood.

year: 2007

title: Predicted hydrodynamic and sediment transport impacts of breakwater construction in Tauranga Harbour, New Zealand

authors: McKenzie, James Scott

subjects: hydrodynamic

abstract: The study predicted the impact of a proposed breakwater development, along the northern boundary of the Tauranga Bridge Marina, on existing hydrodynamics and sediment transport. Numerical modelling was undertaken using the DHI MIKE 21 modelling suite. A 25 m grid resolution regional hydrodynamic model of Tauranga Harbour was established to provide boundary conditions for a 4 m grid resolution local hydrodynamic model of the Stella Passage, Town Reach, and Waipu Bay region. Calibration and verification was achieved by comparing model predictions with measurements from tidal gauges and field deployed ADV instruments. A wave model was set-up to provide predictions of wave-induced sediment transport. A sediment transport model was developed to identify sediment transport pathways and areas of erosion and accretion.

A pile and panel breakwater was recommended based on predictions of reduced current velocity within the marina and a limited increase along the Sulphur Point wharf. Flow diversion and channel constriction contributed to increased maximum velocities of 10% near the Stella Passage drop-off, increased peak tide velocities of up to 0.3 m.s⁻¹ west of the breakwater, and flood jet development off the western tip of the breakwater. Increased accretion north of the drop-off was predicted in response to increased annual spring transport rates in Town Reach from <50 m³/yr/m up to 100 m³/yr/m. Increased erosion through the western side of Town Reach may result in coarser surficial sediment and a westward extension of shell lag. In the western Stella Passage, peak ebb velocities increased by 0.2 – 0.5 m.s⁻¹ and annual spring transport rates increased from <5 m³/yr/m to >10 m³/yr/m. Peak tide velocities within the marina were reduced by 0.2 – 0.5 m.s⁻¹  in the north and up to 0.2 m.s⁻¹ in the south and annual spring transport rates decreased from up to 50 m³/yr/m to predominantly <5 m³/yr/m. 

Two dredging scenarios proposed by the Port of Tauranga were also simulated. In dredging scenario one, the Stella Passage was deepened to 16.0 m below Chart Datum. Variation in flow patterns were predicted within the Stella Passage and flood velocity increased through the western side. In dredging scenario two, the dredged area and Sulphur Point wharf were extended southward into Town Reach. In the western Stella Passage, maximum flood velocity increased by 0.2 m.s⁻¹ and peak ebb velocity increased by up to 0.3 m.s⁻¹. Peak flood velocity decreased by up to 0.3 m.s⁻¹ north of the marina.  

Breakwater addition to the dredging scenario one simulation produced similar results compared with the combined breakwater and existing bathymetry simulation. The breakwater and dredging extension in scenario two, both independently acted to focus flow through west side of Town Reach. Increased erosion was predicted toward the drop-off into the dredging extension. Dredging reduced the influence of the breakwater through the western Stella Passage. The breakwater increased maximum ebb velocity by 29% for the existing bathymetry, 25% for dredging scenario one, and 20% for dredging scenario two. 

Existing sediment transport patterns in Waipu Bay were unaltered by breakwater development or the combined breakwater development and dredging and wharf extensions.

An area of high seabed elevation, in western Waipu Bay, was the preferred location for an artificial bird roost. The existing bathymetry was altered to simulate different dredge island dimensions. The recommended design was oval shaped with an east-west orientation. This design displayed consistently low annual spring transport rates of <0.1 m³/yr/m.

text: Predicted hydrodynamic and sediment transport impacts of breakwater construction in Tauranga Harbour, New Zealand The study predicted the impact of a proposed breakwater development, along the northern boundary of the Tauranga Bridge Marina, on existing hydrodynamics and sediment transport. Numerical modelling was undertaken using the DHI MIKE 21 modelling suite. A 25 m grid resolution regional hydrodynamic model of Tauranga Harbour was established to provide boundary conditions for a 4 m grid resolution local hydrodynamic model of the Stella Passage, Town Reach, and Waipu Bay region. Calibration and verification was achieved by comparing model predictions with measurements from tidal gauges and field deployed ADV instruments. A wave model was set-up to provide predictions of wave-induced sediment transport. A sediment transport model was developed to identify sediment transport pathways and areas of erosion and accretion.

A pile and panel breakwater was recommended based on predictions of reduced current velocity within the marina and a limited increase along the Sulphur Point wharf. Flow diversion and channel constriction contributed to increased maximum velocities of 10% near the Stella Passage drop-off, increased peak tide velocities of up to 0.3 m.s⁻¹ west of the breakwater, and flood jet development off the western tip of the breakwater. Increased accretion north of the drop-off was predicted in response to increased annual spring transport rates in Town Reach from <50 m³/yr/m up to 100 m³/yr/m. Increased erosion through the western side of Town Reach may result in coarser surficial sediment and a westward extension of shell lag. In the western Stella Passage, peak ebb velocities increased by 0.2 – 0.5 m.s⁻¹ and annual spring transport rates increased from <5 m³/yr/m to >10 m³/yr/m. Peak tide velocities within the marina were reduced by 0.2 – 0.5 m.s⁻¹  in the north and up to 0.2 m.s⁻¹ in the south and annual spring transport rates decreased from up to 50 m³/yr/m to predominantly <5 m³/yr/m. 

Two dredging scenarios proposed by the Port of Tauranga were also simulated. In dredging scenario one, the Stella Passage was deepened to 16.0 m below Chart Datum. Variation in flow patterns were predicted within the Stella Passage and flood velocity increased through the western side. In dredging scenario two, the dredged area and Sulphur Point wharf were extended southward into Town Reach. In the western Stella Passage, maximum flood velocity increased by 0.2 m.s⁻¹ and peak ebb velocity increased by up to 0.3 m.s⁻¹. Peak flood velocity decreased by up to 0.3 m.s⁻¹ north of the marina.  

Breakwater addition to the dredging scenario one simulation produced similar results compared with the combined breakwater and existing bathymetry simulation. The breakwater and dredging extension in scenario two, both independently acted to focus flow through west side of Town Reach. Increased erosion was predicted toward the drop-off into the dredging extension. Dredging reduced the influence of the breakwater through the western Stella Passage. The breakwater increased maximum ebb velocity by 29% for the existing bathymetry, 25% for dredging scenario one, and 20% for dredging scenario two. 

Existing sediment transport patterns in Waipu Bay were unaltered by breakwater development or the combined breakwater development and dredging and wharf extensions.

An area of high seabed elevation, in western Waipu Bay, was the preferred location for an artificial bird roost. The existing bathymetry was altered to simulate different dredge island dimensions. The recommended design was oval shaped with an east-west orientation. This design displayed consistently low annual spring transport rates of <0.1 m³/yr/m.

year: 2014

title: Maori and mining in New Zealand and beyond

authors: Hart, Philip

abstract: Before the arrival of Europeans, Maori had known of the existence of gold but did not mine it and had no understanding of its value. Once mining commenced in California in 1849 and Australia in the early 1850s, many Maori participated on several fields, especially in Victoria. When gold was first discovered in New Zealand, at Coromandel in 1852, Maori were keen to learn prospecting skills, and soon found gold in several parts of both the North and South Islands. Some alluvial claims were worked communally, even some women participating. From the start, Maori were determined to protect their rights against Pakeha when they were rivals for the same ground.  
On the Hauraki Peninsula, which had no alluvial gold, Maori were prospectors rather than miners. Some were successful, often going against the wishes of rangatira who, fearing that opening goldfields would result in their losing their land, refused access to prospectors, particularly in Ohinemuri. At Thames, Maori prospectors succeeded where Pakeha ones had failed, finding the gold that led to the 1867 rush; a rush encouraged by one rangatira in particular, Wirope Hoterene Taipari, who understood how a successful field would benefit him financially (including obtaining a reward for discovering a payable goldfield). After the opening of this field, some Maori prospected throughout the peninsula and elsewhere for the remainder of the century, with varying success but with some good finds, particularly at Kuaotunu. A few even participated in the Klondike rush. By the twentieth century, Maori were overcoming their reluctance to mine underground, notably in the coalmines of the Waikato, but until then almost none had seen mining as a full-time career. 
Indigenous inhabitants throughout the world successfully prospected for precious metals, but their achievements were commonly written out of history, as for example in Australia, where Aboriginal involvement is only now being uncovered. In New Zealand also, Maori achievements, although well known to contemporaries, have largely been forgotten. At the time, Maori prospector’s successes were praised and many became owners of claims, and in some cases benefited financially from their involvement in mining.

text: Maori and mining in New Zealand and beyond Before the arrival of Europeans, Maori had known of the existence of gold but did not mine it and had no understanding of its value. Once mining commenced in California in 1849 and Australia in the early 1850s, many Maori participated on several fields, especially in Victoria. When gold was first discovered in New Zealand, at Coromandel in 1852, Maori were keen to learn prospecting skills, and soon found gold in several parts of both the North and South Islands. Some alluvial claims were worked communally, even some women participating. From the start, Maori were determined to protect their rights against Pakeha when they were rivals for the same ground.  
On the Hauraki Peninsula, which had no alluvial gold, Maori were prospectors rather than miners. Some were successful, often going against the wishes of rangatira who, fearing that opening goldfields would result in their losing their land, refused access to prospectors, particularly in Ohinemuri. At Thames, Maori prospectors succeeded where Pakeha ones had failed, finding the gold that led to the 1867 rush; a rush encouraged by one rangatira in particular, Wirope Hoterene Taipari, who understood how a successful field would benefit him financially (including obtaining a reward for discovering a payable goldfield). After the opening of this field, some Maori prospected throughout the peninsula and elsewhere for the remainder of the century, with varying success but with some good finds, particularly at Kuaotunu. A few even participated in the Klondike rush. By the twentieth century, Maori were overcoming their reluctance to mine underground, notably in the coalmines of the Waikato, but until then almost none had seen mining as a full-time career. 
Indigenous inhabitants throughout the world successfully prospected for precious metals, but their achievements were commonly written out of history, as for example in Australia, where Aboriginal involvement is only now being uncovered. In New Zealand also, Maori achievements, although well known to contemporaries, have largely been forgotten. At the time, Maori prospector’s successes were praised and many became owners of claims, and in some cases benefited financially from their involvement in mining.

year: 2016