John Ogden
Biographic Data
| ID | 5597188 |
|---|---|
| NAME | John Ogden |
| GIVEN NAMES | John |
| FAMILY NAME | Ogden |
| SIGNATURE | OGDEN J |
| AFFILIATIONS | University of Auckland |
| VERIFIED | No |
| TOTAL WORKS | 10 |
| TOTAL CITATIONS | 37 |
| AUTHOR COUNT | 10 |
| EDITOR COUNT | 0 |
| FIRST PUBLICATION YEAR | 1988 |
| LATEST PUBLICATION YEAR | 2009 |
| H-INDEX | 3 |
Holocene vegetation and environmental reconstructions from swamp deposits in the Dargaville region of the North Island, New Zealand: Implications for the history of kauri (Agathis australis)
Multiproxy analysis of two swamps, representative of numerous sites in the Dargaville area, provide a Holocene record of a transition from flooded marine valleys to freshwater swamp-forests. Dendrochronology of subfossil wood from these and other associated sites provide a record of kauri ( Agathis) growth and demise over 3600 calendar years. A discrepancy between the abundance of kauri pollen and the timing of maximum kauri forest development, a…
Towards a Radiocarbon Calibration for Oxygen Isotope Stage 3 Using New Zealand Kauri ( Agathis Australis )
It is well known that radiocarbon years do not directly equate to calendar time. As a result, considerable effort has been devoted to generating a decadally resolved calibration curve for the Holocene and latter part of the last termination. A calibration curve that can be unambiguously attributed to changes in atmospheric 14 C content has not, however, been generated beyond 26 kyr cal BP, despite the urgent need to rigorously test climatic, envi…
Extension of the New Zealand kauri (Agathis australis) chronology to 1724 BC
Long tree-ring chronologies have been constructed in the Northern Hemisphere for dendroclimatology and palaeoenvironmental studies, radiocarbon calibration and archaeological dating. Numerous tree-ring chronologies have also been built in the Southern Hemisphere, primarily for dendroclimatology, but multimillennial chronologies are rare. Development of long chronologies from the Southern Hemisphere is therefore important to provide a long-term pe…
Tree-Ring Studies on Agathis australis (Kauri): A Synthesis of Development Work on Late Holocene Chronologies
The potential of kauri (Agathis australis) for paleoclimate research is well established. Multiple tree-ring chronologies have been derived from living and sub-fossil material and growth-climate relationships have been identified. Work has progressed to the stage where raw ring-width data and chronologies covering the last half of the second millennium can confidently be placed in the public domain, to facilitate multi-proxy paleoclimate studies.…
Evidence for Lateglacial and Holocene tree-line fluctuations from pollen diagrams from the Subalpine zone on Mt Hauhungatahi, Tongariro National Park, New Zealand
Pollen diagrams from four sites along an altitudinal sequence on Mt Hauhungatahi support fossil wood data (Ogden et al., 1997) in suggesting a fluctuating Holocene tree-line not exceeding the altitude reached in the early Holocene. Tree-line forest at 1340–1390 m during the periods 10 100–7500 and 5400–3800 cal. BP was associated with patchy Subalpine scrub communities above and below this altitude. Rapid decline of this Halocarpus-Phyllocladus f…
Structure and composition of the subalpine forest on Mount Hauhungatahi, North Island, New Zealand, during the Holocene
Tree stumps of Holocene age were identified and measured at three sites above the present tree-line on Mount Hauhungatahi, Tongariro National Park, New Zealand. Wood and peat were radiocarbon dated and annual rings in stump cross-sections counted for growth-rates. Comparative measurements were made in three plots in the modern subalpine forests. Stem densities and basal areas in the ancient forest were within the range of the modern subalpine for…
C Calibration in the Southern Hemisphere and the Date of the Last Taupo Eruption: Evidence from Tree-Ring Sequences
Tree rings from a section of Prumnopitys taxifolia (matai) covering the period ad 1335–1745 have been radiocarbon dated and used to generate a 14 C calibration curve for southern hemisphere wood. Comparison of this curve with calibration data for northern hemisphere wood does not show a systematic difference between 14 C ages measured in the northern and southern hemispheres. A floating chronology covering 270 yr and terminating at the last Taupo…
A Vegetation History of the Far North of New Zealand during the Late Otira (Last) Glaciation
During the latter part of the last (Otira) glaciation the forest cover of New Zealand was much reduced. It has frequently been postulated, however, that diverse mixed forest communities survived in the far north of North Island. Pollen diagrams and radiocarbon dates from two last glacial and postglacial (Aranuian) sits on the Aupouri Peninsula in the far north of New Zealand are compared with other published palynological and plant macrofossil ev…
Climatic Implications of Macro- and Microfossil Assemblages from Late Pleistocene Deposits in Northern New Zealand
Twenty-two plant species were identified from leaves, fruits, or flowers, and 41 taxa from pollen, present in a macrofossil (leaf) layer in a peat swamp formed on Pleistocene dunes on the Aupouri Peninsula in northern New Zealand. Eight genera of gymnosperms are represented. With the exception of Lagarostrobos colensoi, all tree species abundant as macrofossils are also common as pollen. Macrofossils enabled the on-site flora to be compared with …
Forest dynamics and stand-level dieback in New Zealand'sNothofagus forests
C Calibration in the Southern Hemisphere and the Date of the Last Taupo Eruption: Evidence from Tree-Ring Sequences
Tree rings from a section of Prumnopitys taxifolia (matai) covering the period ad 1335–1745 have been radiocarbon dated and used to generate a 14 C calibration curve for southern hemisphere wood. Comparison of this curve with calibration data for northern hemisphere wood does not show a systematic difference between 14 C ages measured in the northern and southern hemispheres. A floating chronology covering 270 yr and terminating at the last Taupo…
Extension of the New Zealand kauri (Agathis australis) chronology to 1724 BC
Long tree-ring chronologies have been constructed in the Northern Hemisphere for dendroclimatology and palaeoenvironmental studies, radiocarbon calibration and archaeological dating. Numerous tree-ring chronologies have also been built in the Southern Hemisphere, primarily for dendroclimatology, but multimillennial chronologies are rare. Development of long chronologies from the Southern Hemisphere is therefore important to provide a long-term pe…
Towards a Radiocarbon Calibration for Oxygen Isotope Stage 3 Using New Zealand Kauri ( Agathis Australis )
It is well known that radiocarbon years do not directly equate to calendar time. As a result, considerable effort has been devoted to generating a decadally resolved calibration curve for the Holocene and latter part of the last termination. A calibration curve that can be unambiguously attributed to changes in atmospheric 14 C content has not, however, been generated beyond 26 kyr cal BP, despite the urgent need to rigorously test climatic, envi…
Structure and composition of the subalpine forest on Mount Hauhungatahi, North Island, New Zealand, during the Holocene
Tree stumps of Holocene age were identified and measured at three sites above the present tree-line on Mount Hauhungatahi, Tongariro National Park, New Zealand. Wood and peat were radiocarbon dated and annual rings in stump cross-sections counted for growth-rates. Comparative measurements were made in three plots in the modern subalpine forests. Stem densities and basal areas in the ancient forest were within the range of the modern subalpine for…
Forest dynamics and stand-level dieback in New Zealand'sNothofagus forests
Forest dynamics and stand-level dieback in New Zealand'sNothofagus forests
A Vegetation History of the Far North of New Zealand during the Late Otira (Last) Glaciation
During the latter part of the last (Otira) glaciation the forest cover of New Zealand was much reduced. It has frequently been postulated, however, that diverse mixed forest communities survived in the far north of North Island. Pollen diagrams and radiocarbon dates from two last glacial and postglacial (Aranuian) sits on the Aupouri Peninsula in the far north of New Zealand are compared with other published palynological and plant macrofossil ev…
Climatic Implications of Macro- and Microfossil Assemblages from Late Pleistocene Deposits in Northern New Zealand
Twenty-two plant species were identified from leaves, fruits, or flowers, and 41 taxa from pollen, present in a macrofossil (leaf) layer in a peat swamp formed on Pleistocene dunes on the Aupouri Peninsula in northern New Zealand. Eight genera of gymnosperms are represented. With the exception of Lagarostrobos colensoi, all tree species abundant as macrofossils are also common as pollen. Macrofossils enabled the on-site flora to be compared with …
C Calibration in the Southern Hemisphere and the Date of the Last Taupo Eruption: Evidence from Tree-Ring Sequences
Tree rings from a section of Prumnopitys taxifolia (matai) covering the period ad 1335–1745 have been radiocarbon dated and used to generate a 14 C calibration curve for southern hemisphere wood. Comparison of this curve with calibration data for northern hemisphere wood does not show a systematic difference between 14 C ages measured in the northern and southern hemispheres. A floating chronology covering 270 yr and terminating at the last Taupo…
Structure and composition of the subalpine forest on Mount Hauhungatahi, North Island, New Zealand, during the Holocene
Tree stumps of Holocene age were identified and measured at three sites above the present tree-line on Mount Hauhungatahi, Tongariro National Park, New Zealand. Wood and peat were radiocarbon dated and annual rings in stump cross-sections counted for growth-rates. Comparative measurements were made in three plots in the modern subalpine forests. Stem densities and basal areas in the ancient forest were within the range of the modern subalpine for…
Evidence for Lateglacial and Holocene tree-line fluctuations from pollen diagrams from the Subalpine zone on Mt Hauhungatahi, Tongariro National Park, New Zealand
Pollen diagrams from four sites along an altitudinal sequence on Mt Hauhungatahi support fossil wood data (Ogden et al., 1997) in suggesting a fluctuating Holocene tree-line not exceeding the altitude reached in the early Holocene. Tree-line forest at 1340–1390 m during the periods 10 100–7500 and 5400–3800 cal. BP was associated with patchy Subalpine scrub communities above and below this altitude. Rapid decline of this Halocarpus-Phyllocladus f…
Tree-Ring Studies on Agathis australis (Kauri): A Synthesis of Development Work on Late Holocene Chronologies
The potential of kauri (Agathis australis) for paleoclimate research is well established. Multiple tree-ring chronologies have been derived from living and sub-fossil material and growth-climate relationships have been identified. Work has progressed to the stage where raw ring-width data and chronologies covering the last half of the second millennium can confidently be placed in the public domain, to facilitate multi-proxy paleoclimate studies.…
Extension of the New Zealand kauri (Agathis australis) chronology to 1724 BC
Long tree-ring chronologies have been constructed in the Northern Hemisphere for dendroclimatology and palaeoenvironmental studies, radiocarbon calibration and archaeological dating. Numerous tree-ring chronologies have also been built in the Southern Hemisphere, primarily for dendroclimatology, but multimillennial chronologies are rare. Development of long chronologies from the Southern Hemisphere is therefore important to provide a long-term pe…
Towards a Radiocarbon Calibration for Oxygen Isotope Stage 3 Using New Zealand Kauri ( Agathis Australis )
It is well known that radiocarbon years do not directly equate to calendar time. As a result, considerable effort has been devoted to generating a decadally resolved calibration curve for the Holocene and latter part of the last termination. A calibration curve that can be unambiguously attributed to changes in atmospheric 14 C content has not, however, been generated beyond 26 kyr cal BP, despite the urgent need to rigorously test climatic, envi…
Holocene vegetation and environmental reconstructions from swamp deposits in the Dargaville region of the North Island, New Zealand: Implications for the history of kauri (Agathis australis)
Multiproxy analysis of two swamps, representative of numerous sites in the Dargaville area, provide a Holocene record of a transition from flooded marine valleys to freshwater swamp-forests. Dendrochronology of subfossil wood from these and other associated sites provide a record of kauri ( Agathis) growth and demise over 3600 calendar years. A discrepancy between the abundance of kauri pollen and the timing of maximum kauri forest development, a…
Geology and Paleoclimatology Research (9 works) · Geography (8 works) · Geology (6 works) · Holocene (6 works) · Radiocarbon dating (6 works) · Archaeology (5 works) · Biology (5 works) · Chronology (5 works) · Physical geography (5 works) · Ecology (4 works)