title: Changes in soil carbon stocks of New Zealand’s grazed pasture in response to variations in management and environmental factors.

authors: Kirschbaum, Miko U.F.

subjects: CenW

abstract: Dairy farming is New Zealand‟s pre-eminent primary industry. It achieves large export earnings but is also responsible for a large proportion of the country‟s greenhouse gas emissions. One of those greenhouse gases is CO₂, and in order to lower New Zealand‟s net greenhouse gas emissions, it is important to identify any management options that can lead to carbon sequestration in pasture soils and thereby minimise net CO₂ emissions to the atmosphere. It is equally important to understand what factors could lead to losses of soil carbon from pasture soils and thereby add further to New Zealand‟s CO₂ emissions. 
We addressed these questions by using two years of observations from an eddy-covariance system on a dairy farm in the Waikato that provided estimates of the exchanges of water and CO₂ with the atmosphere. We used CenW 4.1, a process-based ecosystem model, to describe these observations in terms of their biophysical drivers and the interactions between them. Agreement between the model and observations was excellent, especially for evapotranspiration and net photosynthesis, for which 91% and 79% of observed daily variations could be explained. 
The validated model was then used to run different scenarios to assess the effects on soil organic carbon of changes in the application of fertiliser and irrigation water, grazing scheduling, differences in plant-internal resource allocation, and changes in temperature and CO₂ concentration. We found that it was important to consider the combined effect of changes in net primary production, the amount of carbon taken off-site through grazing, the proportion of carbon allocated to pools, especially pools in the soil, that facilitates the stabilisation of carbon in organic matter, and any changes in the rate of organic matter decomposition. 
Soil organic carbon stocks were positively correlated with rates of fertiliser application and with the rate of water application (rain or irrigation) up to some moderate water application rates. For other changes in key properties, changes in soil organic carbon were often negatively correlated with changes in milk production. That was clearly evident for changes in the grazing regime and in plant root:shoot ratios. Anticipated environmental changes, such as increases in temperature and CO₂ concentration, and both increases and decreases in precipitation from moderate values had either neutral or detrimental effects on soil organic carbon stocks. Milk production was generally more positively affected under most environmental changes.

text: Changes in soil carbon stocks of New Zealand’s grazed pasture in response to variations in management and environmental factors. Dairy farming is New Zealand‟s pre-eminent primary industry. It achieves large export earnings but is also responsible for a large proportion of the country‟s greenhouse gas emissions. One of those greenhouse gases is CO₂, and in order to lower New Zealand‟s net greenhouse gas emissions, it is important to identify any management options that can lead to carbon sequestration in pasture soils and thereby minimise net CO₂ emissions to the atmosphere. It is equally important to understand what factors could lead to losses of soil carbon from pasture soils and thereby add further to New Zealand‟s CO₂ emissions. 
We addressed these questions by using two years of observations from an eddy-covariance system on a dairy farm in the Waikato that provided estimates of the exchanges of water and CO₂ with the atmosphere. We used CenW 4.1, a process-based ecosystem model, to describe these observations in terms of their biophysical drivers and the interactions between them. Agreement between the model and observations was excellent, especially for evapotranspiration and net photosynthesis, for which 91% and 79% of observed daily variations could be explained. 
The validated model was then used to run different scenarios to assess the effects on soil organic carbon of changes in the application of fertiliser and irrigation water, grazing scheduling, differences in plant-internal resource allocation, and changes in temperature and CO₂ concentration. We found that it was important to consider the combined effect of changes in net primary production, the amount of carbon taken off-site through grazing, the proportion of carbon allocated to pools, especially pools in the soil, that facilitates the stabilisation of carbon in organic matter, and any changes in the rate of organic matter decomposition. 
Soil organic carbon stocks were positively correlated with rates of fertiliser application and with the rate of water application (rain or irrigation) up to some moderate water application rates. For other changes in key properties, changes in soil organic carbon were often negatively correlated with changes in milk production. That was clearly evident for changes in the grazing regime and in plant root:shoot ratios. Anticipated environmental changes, such as increases in temperature and CO₂ concentration, and both increases and decreases in precipitation from moderate values had either neutral or detrimental effects on soil organic carbon stocks. Milk production was generally more positively affected under most environmental changes.

year: 2015

title: The whole-plant compensation point as a measure of juvenile tree light requirements

authors: Lusk, Christopher H.

subjects: forest dynamics

abstract: 1.	Although ‘shade tolerance’ has featured prominently in the vocabulary of foresters and ecologists for a century, we have yet to agree on a standardized method for quantifying this elusive property. The ‘whole-plant compensation point’, interpolated from stem growth measurements across a wide range of light environments, has been proposed as a simple, robust measure of species shade tolerance. Others have argued that shade tolerance is primarily a function of differential ability to survive periods of slow growth (‘suppression’), implying that measurements of survival are vital.
2.	We measured growth of juveniles (500–1000 mm tall) of five evergreen trees over 12 months in a cool-temperate rain forest in New Zealand, to determine whether whole-plant compensation points predicted species differences in occupancy of understorey light environments, which were quantified using hemispherical photography.
3.	The five species encompassed 3•5-fold variation in whole-plant compensation points. Compensation points of most species fell within the first quartile of the distribution of light environments occupied by juveniles; they were also correlated with low-light mortality rates of juveniles, estimated from permanent plot data archived in the National Vegetation Survey Databank. Compensation points were also significantly positively correlated with height growth rates in high light, confirming the presence of the growth vs. shade tolerance trade-off detected in many other forest tree assemblages.
4.	Results show that, in temperate evergreen forests, the whole-plant compensation point distinguishes reliably between species of differing shade tolerance. Excepting situations involving parameterization of demographic models, shade tolerance can therefore be assessed without survival measurements. However, estimating whole-plant compensation points may prove more difficult in deciduous forests, where seasonal variation in understorey light transmission poses additional challenges.

text: The whole-plant compensation point as a measure of juvenile tree light requirements 1.	Although ‘shade tolerance’ has featured prominently in the vocabulary of foresters and ecologists for a century, we have yet to agree on a standardized method for quantifying this elusive property. The ‘whole-plant compensation point’, interpolated from stem growth measurements across a wide range of light environments, has been proposed as a simple, robust measure of species shade tolerance. Others have argued that shade tolerance is primarily a function of differential ability to survive periods of slow growth (‘suppression’), implying that measurements of survival are vital.
2.	We measured growth of juveniles (500–1000 mm tall) of five evergreen trees over 12 months in a cool-temperate rain forest in New Zealand, to determine whether whole-plant compensation points predicted species differences in occupancy of understorey light environments, which were quantified using hemispherical photography.
3.	The five species encompassed 3•5-fold variation in whole-plant compensation points. Compensation points of most species fell within the first quartile of the distribution of light environments occupied by juveniles; they were also correlated with low-light mortality rates of juveniles, estimated from permanent plot data archived in the National Vegetation Survey Databank. Compensation points were also significantly positively correlated with height growth rates in high light, confirming the presence of the growth vs. shade tolerance trade-off detected in many other forest tree assemblages.
4.	Results show that, in temperate evergreen forests, the whole-plant compensation point distinguishes reliably between species of differing shade tolerance. Excepting situations involving parameterization of demographic models, shade tolerance can therefore be assessed without survival measurements. However, estimating whole-plant compensation points may prove more difficult in deciduous forests, where seasonal variation in understorey light transmission poses additional challenges.

year: 2013

title: Te aho tapu: Mātauranga a Māui ancient knowledge and preserving culture through practice

authors: Keelan-Peebles, Jacqueline Roberta

abstract: I am Māui I am not Māori. Reclamation of identity as uri o Māui-tikitiki-a-Taranga is the ngako of  this creative thesis, in response to the question, ‘who were we before and what is Māuitanga’? 
Due to its paucity my intention is to revive its frequency in restoration to its rightful status in this way; the tools to navigate authentication is through the lens of mātauranga Māui, embedded in kōrero tawhito, traditional cultural practice, lived experience and whakapapa. Validation is  founded in our iwi repositories, pūrākau, ngā waiata, mōteatea, karakia, whaikōrero, rituals of encounter and the arts.
Raranga as the creative vehicle affords the means to analogize kaupapa Māui. The creation of a Kākahu/Korowai is the appropriate representation as its significance aligns itself with the mantle of honour due to rangatira living and those who have passed. 
Exploration of kaupapa Māui infrastructure is fundamental to unravelling multi-faceted cultural narratives. These are the mechanisms to the reclamation of who we were before and to answer the question of Māuitanga. Ultimately to claim and to restore my heritage, to reinstate the common use of an ancient iwi, te iwi ‛Māui’.

text: Te aho tapu: Mātauranga a Māui ancient knowledge and preserving culture through practice I am Māui I am not Māori. Reclamation of identity as uri o Māui-tikitiki-a-Taranga is the ngako of  this creative thesis, in response to the question, ‘who were we before and what is Māuitanga’? 
Due to its paucity my intention is to revive its frequency in restoration to its rightful status in this way; the tools to navigate authentication is through the lens of mātauranga Māui, embedded in kōrero tawhito, traditional cultural practice, lived experience and whakapapa. Validation is  founded in our iwi repositories, pūrākau, ngā waiata, mōteatea, karakia, whaikōrero, rituals of encounter and the arts.
Raranga as the creative vehicle affords the means to analogize kaupapa Māui. The creation of a Kākahu/Korowai is the appropriate representation as its significance aligns itself with the mantle of honour due to rangatira living and those who have passed. 
Exploration of kaupapa Māui infrastructure is fundamental to unravelling multi-faceted cultural narratives. These are the mechanisms to the reclamation of who we were before and to answer the question of Māuitanga. Ultimately to claim and to restore my heritage, to reinstate the common use of an ancient iwi, te iwi ‛Māui’.

year: 2022