Proceedings of the New Zealand Grassland Association, 1976
The relationships of growth and flowering to nonstructural carbohydrate reserve storage and the i... more The relationships of growth and flowering to nonstructural carbohydrate reserve storage and the influence of the pastoral management practice of burning on these relationships were investigated in Chionochloa rigida and C. macra on the Old Man Range, Central Otago
Increased dieback in Westland rata (Metrosideros umbellata) kamahi (Weinmannia racemosa) forests ... more Increased dieback in Westland rata (Metrosideros umbellata) kamahi (Weinmannia racemosa) forests has been linked to the build-up of populations of the Australian brush-tailed possum (Trichosurus vulpecula). Within these forests young even-aged stands are observed to be more resilient to dieback than older stands. The effect of possum browsing on individual rata trees was related to the level of defoliation. Trees which had been not or only lightly browsed maintained intact canopies. Where browsing resulted in canopy opening exposed leaf bunches continued to deteriorate, even in the absence of further browsing. In even-aged rata-kamahi stands which were still undergoing natural thinning crown size was small, and the loss of individual trees (whether by competition or possum browsing), did not affect the ability of the stand to maintain an intact canopy cover. Once thinning was complete, the loss of large crowned mature trees led to the opening up of the stand and to continuing damage...
Soil carbon stock change between two major land uses in New Zealand was measured by sampling pair... more Soil carbon stock change between two major land uses in New Zealand was measured by sampling paired plots across the boundaries of low productivity grassland and forest planted pre‐1990. The national soil carbon monitoring system uses low productivity grassland as a benchmark to evaluate soil carbon stock change for other land uses. The goal was to validate earlier estimates of the effect of pre‐1990 afforestation and to reduce their level of uncertainty. We selected a set of sites to represent the national stocks of forests planted pre‐1990. Previous studies derived estimates of the land‐use effect on soil carbon for afforestation ranging from +1.6 to −8.5 t/ha to 30 cm depth. For all estimates, the 95% confidence interval spanned zero. Our study used nine of the previous paired‐plot sites and sampled and analysed 21 new sites. The land‐use effect of change from grassland to forest planted pre‐1990 was estimated at −17.4 t/ha. The 95% confidence interval ranged from −10.1 to −24.6 t/ha and did not include zero change. The result supported the soil carbon monitoring system assumption that forests planted pre‐1990 have significantly lower soil carbon stocks than the low‐productivity‐grassland standard. Evidence of stock change occurred in depth increments to 0.2 m but with no significant change for the 0.2–0.3 m increment. This suggests that the sampling depth of 0.3 m was adequate for the estimation of soil carbon stock change.
Previously published results on certain short-term physiological responses to the spring burning ... more Previously published results on certain short-term physiological responses to the spring burning of narrow-leaved snow tussock, Chionochloa rigida, have been confirmed and extended to include nonstructural carbohydrate reserves and to cover a greatly extended response period of 14 years. Vegetative growth, measured as leaf elongation, increased significantly during the first two post-fire seasons, but then declined relative to that of adjacent unburnt plants. Production of new leaves and tillers, which both increased significantly in the two seasons after fire, was not subsequently significantly depressed. Although narrow-leaved snow tussock is characterised by capricious flowering, flowering was invariably prolific in the first season after burning. Flowering then declined relative to that of unburnt plants, over the next 13 seasons. Mean seasonal levels of nonstructural carbohydrate reserves, in both leaf and stem tissue, were significantly depressed in the year after spring burning. Thereafter, the small increase in mean seasonal carbohydrate levels, over those in unburnt plants, appeared to reflect rather than determine growth patterns. Reburning produced a response similar to that of the initial fire, but the magnitude of the response increased with the interval between fires. Above-ground biomass of tussock recovered slowly after burning and required about 14 years to approach that of nearby unburnt plants. Application of the results to the management and conservation of the grasslands dominated by C. rigida is discussed and suggestions offered to account for some of the responses this species shows to burning that have yet to be adequately explained.
Many studies have quantified uncertainty in forest carbon (C) storage estimation, but there is li... more Many studies have quantified uncertainty in forest carbon (C) storage estimation, but there is little work examining the degree of uncertainty in shrubland C storage estimates. We used field data to simulate uncertainty in carbon storage estimates from three error sources: (1) allometric biomass equations; (2) measurement errors of shrubs harvested for the allometry; and (3) measurement errors of shrubs in survey plots. We also assessed uncertainty for all possible combinations of these error sources. Allometric uncertainty had the greatest independent effect on C storage estimates for individual plots. The largest error arose when all three error sources were included in simulations (where the 95% confidence interval spanned a range equivalent to 40% of mean C storage). Mean C sequestration (1.73 Mg C ha-1 year-1) exceeded the margin of error produced by the simulated sources of uncertainty. This demonstrates that, even when the major sources of uncertainty were accounted for, we were able to detect relatively modest gains in shrubland C storage.
This article discusses the development of a monitoring system to estimate carbon sequestration in... more This article discusses the development of a monitoring system to estimate carbon sequestration in New Zealand's planted Kyoto forests, those forests that have been planted since January 1, 1990, on land that previously did not contain forest. The system must meet the Intergovernmental Panel on Climate Change good practice guidance and must be seen to be unbiased, transparent, and verifiable. At the same time, the system should meet a wider set of objectives for international forest reporting and forest health. The core of the system is to be a network of some 400 permanent sample points, established objectively on a 4- by 4-km grid coincident with an area of Kyoto forest. Each sample point is a cluster of four 0.04-ha circular plots installed in a design similar to that employed in the United States Forest Inventory and Analysis program. Sufficient data are collected at each point to enable the carbon density in each of the required reporting pools to be calculated or modelled. ...
Brushtail possums (Trichosurus vulpecula) tend to eat young canopy foliage in southern rata (Metr... more Brushtail possums (Trichosurus vulpecula) tend to eat young canopy foliage in southern rata (Metrosideros umbellata), and browsing tends to be concentrated on only a few trees. Samples collected as part of an artificial defoliation experiment were analysed for NPK (nitrogen, phosphorus, and potassium), carbohydrate, and polyphenolic concentrations to determine whether changes in foliar chemistry associated with defoliation provide an explanation for these patterns of browsing. In non-defoliated trees, NPK concentrations were highest in young leaves and declined with age, while concentrations of carbohydrates and polyphenolics were independent of leaf age. Nitrogen, phosphorus and polyphenolic concentrations were consistently higher in canopy (sun) versus subcanopy (shade) foliage regardless of leaf age, a trend that was reversed for potassium. Partial (50%) defoliation had little effect on foliar chemistry, regardless of its timing. Total (100%) defoliation stimulated NPK concentrat...
Bryophytes are widespread in many plant communities and can attain cover and biomass levels that ... more Bryophytes are widespread in many plant communities and can attain cover and biomass levels that influence ecosystem processes. We investigated the impact of disturbance (fire, topsoil removal) on the composition, biomass, and water storage capacity of bryophytes in indigenous temperate tall-tussock grasslands managed to sustain an ecosystem service (regular provision of water) to nearby urban areas. We surveyed bryophyte composition, structure and water-related traits 9 years after experimental fires and topsoil removal. Total water storage capacity of non-epiphytic bryophytes in control grassland sites was estimated at 4.3 mm, a value similar to that found in temperate New Zealand forests. Total biomass, species composition, and water- related traits were the main drivers of water storage potential from bryophytes. A major shift in bryophyte species composition following disturbances reduced this potential by over 80%. Bryophyte community changed from a dense ground cover (71%) of...
Science for Conservation is a scientific monograph series presenting research funded by New Zeala... more Science for Conservation is a scientific monograph series presenting research funded by New Zealand Department of Conservation (DOC). Manuscripts are internally and externally peer-reviewed; resulting publications are considered part of the formal international scientific literature. Titles are listed in the DOC Science Publishing catalogue on the departmental website http:// www.doc.govt.nz and printed copies can be purchased from
Brushtail possums (Trichosurus vulpecula) now occupy most areas within New Zealand that are suita... more Brushtail possums (Trichosurus vulpecula) now occupy most areas within New Zealand that are suitable for plantation forestry. Possums browse the terminal shoots of pine seedlings, bite and strip the bark of young stems to get at the cambial tissue, remove needles and cones, and bend or break terminal shoots and lateral branches in the upper portion of the tree. Damage is most commonly reported from young stands. It rarely kills established trees, but can lead to reduced vigour, loss of apical dominance, and an increased incidence of fungal diseases. Where possums are suspected of damaging pine plantations forest managers need to be able to determine when control is required, which areas should have priority, whether control achieves its goals, and when further control measures will be necessary. Reliable inferences and predictions about possum damage can only be obtained from robust, quantitative data. In this manual we discuss the design of surveys to monitor possum damage in pine plantations, and describe a new method for assessing possum damage to pine trees. Canopy Indicator Assessment is a scoring method that uses ground-based assessment of individual trees to determine the nature and extent of possum damage within pine stands, and the degree to which this is reduced as a result of possum control operations. Options for analysing data are outlined.
Laoma s.str., based on Laoma leimonias (Gray, 1850), also includes L. marina (Hutton, 1883), L. o... more Laoma s.str., based on Laoma leimonias (Gray, 1850), also includes L. marina (Hutton, 1883), L. ordishi Climo n. sp., L. labyrinthica Powell, 1948 and L. nerissa (Hutton, 1883), which is reinstated as a valid species. Recently collected material of these Laoma spp. from a wide spread of localities in New Zealand shows that reabsorption of apertural lamellae during growth does not change their configuration in the manner proposed by Suter (1891: 283-285). All species discussed here are endemic to New Zealand. They overlap tightly in their distribution but are often allopatric at local scale, around Auckland-Waitemata-Hauraki Gulf, North Island, while elsewhere they are geographically well-separated. The naturally uncommon L. labyrinthica (Three Kings Islands) is the only species of conservation concern in this group.
Background: Ecosystem representation is one key component in assessing the biodiversity impacts o... more Background: Ecosystem representation is one key component in assessing the biodiversity impacts of land-use changes that will irrevocably alter natural ecosystems. We show how detailed vegetation plot data can be used to assess the potential impact of inundation by a proposed hydroelectricity dam in the Mokihinui gorge, New Zealand, on representation of natural forests. Specifically we ask: 1) How well are the types of forest represented locally, regionally, and nationally; and 2) How does the number of distinct communities (i.e. beta diversity) in the target catchment compare with other catchments nationally? Methods: For local and regional comparisons plant species composition was recorded on 45 objectively located 400 m2 vegetation plots established in each of three gorges, with one being the proposed inundation area of the Mokihinui lower gorge. The fuzzy classification framework of noise clustering was used to assign these plots to a specific alliance and association of a pre-existing national-scale classification. Nationally, we examined the relationship between the number of alliances and associations in a catchment and either catchment size or the number of plots per catchment by fitting Generalised Additive Models.
This article discusses the development of a monitoring system to estimate carbon sequestration in... more This article discusses the development of a monitoring system to estimate carbon sequestration in New Zealand's planted Kyoto forests, those forests that have been planted since January 1, 1990, on land that previously did not contain forest. The system must meet the Intergovernmental Panel on Climate Change good practice guidance and must be seen to be unbiased, transparent, and verifiable.
This article discusses the development of a monitoring system to estimate carbon sequestration in... more This article discusses the development of a monitoring system to estimate carbon sequestration in New Zealand's planted Kyoto forests, those forests that have been planted since January 1, 1990, on land that previously did not contain forest. The system must meet the Intergovernmental Panel on Climate Change good practice guidance and must be seen to be unbiased, transparent, and verifiable. At the same time, the system should meet a wider set of objectives for international forest reporting and forest health. The core of the system is to be a network of some 400 permanent sample points, established objectively on a 4-by 4-km grid coincident with an area of Kyoto forest. Each sample point is a cluster of four 0.04-ha circular plots installed in a design similar to that employed in the United States Forest Inventory and Analysis program. Sufficient data are collected at each point to enable the carbon density in each of the required reporting pools to be calculated or modelled. At a subset of points, integrated with an existing system implemented on an 8-km square grid over New Zealand's indigenous forest and shrubland, assessments of soil carbon and plant biodiversity are made. The intention is that the inventory will have a 3-year measurement cycle, with one-third of the points remeasured each year.
Proceedings of the New Zealand Grassland Association, 1976
The relationships of growth and flowering to nonstructural carbohydrate reserve storage and the i... more The relationships of growth and flowering to nonstructural carbohydrate reserve storage and the influence of the pastoral management practice of burning on these relationships were investigated in Chionochloa rigida and C. macra on the Old Man Range, Central Otago
Increased dieback in Westland rata (Metrosideros umbellata) kamahi (Weinmannia racemosa) forests ... more Increased dieback in Westland rata (Metrosideros umbellata) kamahi (Weinmannia racemosa) forests has been linked to the build-up of populations of the Australian brush-tailed possum (Trichosurus vulpecula). Within these forests young even-aged stands are observed to be more resilient to dieback than older stands. The effect of possum browsing on individual rata trees was related to the level of defoliation. Trees which had been not or only lightly browsed maintained intact canopies. Where browsing resulted in canopy opening exposed leaf bunches continued to deteriorate, even in the absence of further browsing. In even-aged rata-kamahi stands which were still undergoing natural thinning crown size was small, and the loss of individual trees (whether by competition or possum browsing), did not affect the ability of the stand to maintain an intact canopy cover. Once thinning was complete, the loss of large crowned mature trees led to the opening up of the stand and to continuing damage...
Soil carbon stock change between two major land uses in New Zealand was measured by sampling pair... more Soil carbon stock change between two major land uses in New Zealand was measured by sampling paired plots across the boundaries of low productivity grassland and forest planted pre‐1990. The national soil carbon monitoring system uses low productivity grassland as a benchmark to evaluate soil carbon stock change for other land uses. The goal was to validate earlier estimates of the effect of pre‐1990 afforestation and to reduce their level of uncertainty. We selected a set of sites to represent the national stocks of forests planted pre‐1990. Previous studies derived estimates of the land‐use effect on soil carbon for afforestation ranging from +1.6 to −8.5 t/ha to 30 cm depth. For all estimates, the 95% confidence interval spanned zero. Our study used nine of the previous paired‐plot sites and sampled and analysed 21 new sites. The land‐use effect of change from grassland to forest planted pre‐1990 was estimated at −17.4 t/ha. The 95% confidence interval ranged from −10.1 to −24.6 t/ha and did not include zero change. The result supported the soil carbon monitoring system assumption that forests planted pre‐1990 have significantly lower soil carbon stocks than the low‐productivity‐grassland standard. Evidence of stock change occurred in depth increments to 0.2 m but with no significant change for the 0.2–0.3 m increment. This suggests that the sampling depth of 0.3 m was adequate for the estimation of soil carbon stock change.
Previously published results on certain short-term physiological responses to the spring burning ... more Previously published results on certain short-term physiological responses to the spring burning of narrow-leaved snow tussock, Chionochloa rigida, have been confirmed and extended to include nonstructural carbohydrate reserves and to cover a greatly extended response period of 14 years. Vegetative growth, measured as leaf elongation, increased significantly during the first two post-fire seasons, but then declined relative to that of adjacent unburnt plants. Production of new leaves and tillers, which both increased significantly in the two seasons after fire, was not subsequently significantly depressed. Although narrow-leaved snow tussock is characterised by capricious flowering, flowering was invariably prolific in the first season after burning. Flowering then declined relative to that of unburnt plants, over the next 13 seasons. Mean seasonal levels of nonstructural carbohydrate reserves, in both leaf and stem tissue, were significantly depressed in the year after spring burning. Thereafter, the small increase in mean seasonal carbohydrate levels, over those in unburnt plants, appeared to reflect rather than determine growth patterns. Reburning produced a response similar to that of the initial fire, but the magnitude of the response increased with the interval between fires. Above-ground biomass of tussock recovered slowly after burning and required about 14 years to approach that of nearby unburnt plants. Application of the results to the management and conservation of the grasslands dominated by C. rigida is discussed and suggestions offered to account for some of the responses this species shows to burning that have yet to be adequately explained.
Many studies have quantified uncertainty in forest carbon (C) storage estimation, but there is li... more Many studies have quantified uncertainty in forest carbon (C) storage estimation, but there is little work examining the degree of uncertainty in shrubland C storage estimates. We used field data to simulate uncertainty in carbon storage estimates from three error sources: (1) allometric biomass equations; (2) measurement errors of shrubs harvested for the allometry; and (3) measurement errors of shrubs in survey plots. We also assessed uncertainty for all possible combinations of these error sources. Allometric uncertainty had the greatest independent effect on C storage estimates for individual plots. The largest error arose when all three error sources were included in simulations (where the 95% confidence interval spanned a range equivalent to 40% of mean C storage). Mean C sequestration (1.73 Mg C ha-1 year-1) exceeded the margin of error produced by the simulated sources of uncertainty. This demonstrates that, even when the major sources of uncertainty were accounted for, we were able to detect relatively modest gains in shrubland C storage.
This article discusses the development of a monitoring system to estimate carbon sequestration in... more This article discusses the development of a monitoring system to estimate carbon sequestration in New Zealand's planted Kyoto forests, those forests that have been planted since January 1, 1990, on land that previously did not contain forest. The system must meet the Intergovernmental Panel on Climate Change good practice guidance and must be seen to be unbiased, transparent, and verifiable. At the same time, the system should meet a wider set of objectives for international forest reporting and forest health. The core of the system is to be a network of some 400 permanent sample points, established objectively on a 4- by 4-km grid coincident with an area of Kyoto forest. Each sample point is a cluster of four 0.04-ha circular plots installed in a design similar to that employed in the United States Forest Inventory and Analysis program. Sufficient data are collected at each point to enable the carbon density in each of the required reporting pools to be calculated or modelled. ...
Brushtail possums (Trichosurus vulpecula) tend to eat young canopy foliage in southern rata (Metr... more Brushtail possums (Trichosurus vulpecula) tend to eat young canopy foliage in southern rata (Metrosideros umbellata), and browsing tends to be concentrated on only a few trees. Samples collected as part of an artificial defoliation experiment were analysed for NPK (nitrogen, phosphorus, and potassium), carbohydrate, and polyphenolic concentrations to determine whether changes in foliar chemistry associated with defoliation provide an explanation for these patterns of browsing. In non-defoliated trees, NPK concentrations were highest in young leaves and declined with age, while concentrations of carbohydrates and polyphenolics were independent of leaf age. Nitrogen, phosphorus and polyphenolic concentrations were consistently higher in canopy (sun) versus subcanopy (shade) foliage regardless of leaf age, a trend that was reversed for potassium. Partial (50%) defoliation had little effect on foliar chemistry, regardless of its timing. Total (100%) defoliation stimulated NPK concentrat...
Bryophytes are widespread in many plant communities and can attain cover and biomass levels that ... more Bryophytes are widespread in many plant communities and can attain cover and biomass levels that influence ecosystem processes. We investigated the impact of disturbance (fire, topsoil removal) on the composition, biomass, and water storage capacity of bryophytes in indigenous temperate tall-tussock grasslands managed to sustain an ecosystem service (regular provision of water) to nearby urban areas. We surveyed bryophyte composition, structure and water-related traits 9 years after experimental fires and topsoil removal. Total water storage capacity of non-epiphytic bryophytes in control grassland sites was estimated at 4.3 mm, a value similar to that found in temperate New Zealand forests. Total biomass, species composition, and water- related traits were the main drivers of water storage potential from bryophytes. A major shift in bryophyte species composition following disturbances reduced this potential by over 80%. Bryophyte community changed from a dense ground cover (71%) of...
Science for Conservation is a scientific monograph series presenting research funded by New Zeala... more Science for Conservation is a scientific monograph series presenting research funded by New Zealand Department of Conservation (DOC). Manuscripts are internally and externally peer-reviewed; resulting publications are considered part of the formal international scientific literature. Titles are listed in the DOC Science Publishing catalogue on the departmental website http:// www.doc.govt.nz and printed copies can be purchased from
Brushtail possums (Trichosurus vulpecula) now occupy most areas within New Zealand that are suita... more Brushtail possums (Trichosurus vulpecula) now occupy most areas within New Zealand that are suitable for plantation forestry. Possums browse the terminal shoots of pine seedlings, bite and strip the bark of young stems to get at the cambial tissue, remove needles and cones, and bend or break terminal shoots and lateral branches in the upper portion of the tree. Damage is most commonly reported from young stands. It rarely kills established trees, but can lead to reduced vigour, loss of apical dominance, and an increased incidence of fungal diseases. Where possums are suspected of damaging pine plantations forest managers need to be able to determine when control is required, which areas should have priority, whether control achieves its goals, and when further control measures will be necessary. Reliable inferences and predictions about possum damage can only be obtained from robust, quantitative data. In this manual we discuss the design of surveys to monitor possum damage in pine plantations, and describe a new method for assessing possum damage to pine trees. Canopy Indicator Assessment is a scoring method that uses ground-based assessment of individual trees to determine the nature and extent of possum damage within pine stands, and the degree to which this is reduced as a result of possum control operations. Options for analysing data are outlined.
Laoma s.str., based on Laoma leimonias (Gray, 1850), also includes L. marina (Hutton, 1883), L. o... more Laoma s.str., based on Laoma leimonias (Gray, 1850), also includes L. marina (Hutton, 1883), L. ordishi Climo n. sp., L. labyrinthica Powell, 1948 and L. nerissa (Hutton, 1883), which is reinstated as a valid species. Recently collected material of these Laoma spp. from a wide spread of localities in New Zealand shows that reabsorption of apertural lamellae during growth does not change their configuration in the manner proposed by Suter (1891: 283-285). All species discussed here are endemic to New Zealand. They overlap tightly in their distribution but are often allopatric at local scale, around Auckland-Waitemata-Hauraki Gulf, North Island, while elsewhere they are geographically well-separated. The naturally uncommon L. labyrinthica (Three Kings Islands) is the only species of conservation concern in this group.
Background: Ecosystem representation is one key component in assessing the biodiversity impacts o... more Background: Ecosystem representation is one key component in assessing the biodiversity impacts of land-use changes that will irrevocably alter natural ecosystems. We show how detailed vegetation plot data can be used to assess the potential impact of inundation by a proposed hydroelectricity dam in the Mokihinui gorge, New Zealand, on representation of natural forests. Specifically we ask: 1) How well are the types of forest represented locally, regionally, and nationally; and 2) How does the number of distinct communities (i.e. beta diversity) in the target catchment compare with other catchments nationally? Methods: For local and regional comparisons plant species composition was recorded on 45 objectively located 400 m2 vegetation plots established in each of three gorges, with one being the proposed inundation area of the Mokihinui lower gorge. The fuzzy classification framework of noise clustering was used to assign these plots to a specific alliance and association of a pre-existing national-scale classification. Nationally, we examined the relationship between the number of alliances and associations in a catchment and either catchment size or the number of plots per catchment by fitting Generalised Additive Models.
This article discusses the development of a monitoring system to estimate carbon sequestration in... more This article discusses the development of a monitoring system to estimate carbon sequestration in New Zealand's planted Kyoto forests, those forests that have been planted since January 1, 1990, on land that previously did not contain forest. The system must meet the Intergovernmental Panel on Climate Change good practice guidance and must be seen to be unbiased, transparent, and verifiable.
This article discusses the development of a monitoring system to estimate carbon sequestration in... more This article discusses the development of a monitoring system to estimate carbon sequestration in New Zealand's planted Kyoto forests, those forests that have been planted since January 1, 1990, on land that previously did not contain forest. The system must meet the Intergovernmental Panel on Climate Change good practice guidance and must be seen to be unbiased, transparent, and verifiable. At the same time, the system should meet a wider set of objectives for international forest reporting and forest health. The core of the system is to be a network of some 400 permanent sample points, established objectively on a 4-by 4-km grid coincident with an area of Kyoto forest. Each sample point is a cluster of four 0.04-ha circular plots installed in a design similar to that employed in the United States Forest Inventory and Analysis program. Sufficient data are collected at each point to enable the carbon density in each of the required reporting pools to be calculated or modelled. At a subset of points, integrated with an existing system implemented on an 8-km square grid over New Zealand's indigenous forest and shrubland, assessments of soil carbon and plant biodiversity are made. The intention is that the inventory will have a 3-year measurement cycle, with one-third of the points remeasured each year.
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