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Growth and yield of New Zealand kauri (Agathis australis (D. Don) Lindl.)Steward, Gregory Alan January 2011 (has links)
The growth and productivity of kauri (Agathis australis (D. Don) Lindl.) in even-aged single-species planted stands and mixed-aged second-growth natural stands has been studied. Stand-level models of height, basal area and whole-tree volume were developed. Kauri growth and productivity in planted stands up to 83 years old were compared to that of natural stands that were up to 196 years of age. Within natural stands, the effect of thinning treatments on growth and productivity was also assessed.
Models of growth and productivity were initially developed for each of the three different kauri stand types independently (planted, second-growth unthinned and thinned). Combined data sets allowed for the development of single models that were able to fit all stands. A Schumacher equation with local slope parameter and asymptote bounded at 45 m gave the best fit for height growth, while a von Bertalanffy-Richards equation in difference form with local slope parameter gave the best fit for basal area growth. Kauri in all stand types were found to be slow to establish with little height growth in planted stands for the first five years after planting, and for the first 25 years in natural stands. Similar trends were observed for basal area and whole-tree volume development. Models developed in this study are relevant only to kauri in the “ricker” or monopodial form irrespective of age, and for stands from 320-2000 stems/ha.
Kauri growth and productivity in planted stands was substantively better than that in second-growth stands. Planted kauri had height increment of 0.4 m/yr for periods of up to 30 years. At age 50, planted kauri was predicted to be 20 m in height, over twice the height of kauri in natural stands, and to be 28.1 m by 100 years. Basal area at age 50 averaged 64.9 m2/ha for all planted stands, and was predicted to be 98.2 m2/ha at age 100. Whole-tree volume was predicted to increase by 11.7 m3/ha/annum for all stands, but was as high as 20.6 m3/ha/yr in one 70 year old stand. The maximum productivity of kauri was observed in one high-performing young kauri planted stand where whole-tree volume increment in excess of 30 m3/ha/yr were predicted for a period from age 15-30. Carbon sequestration was calculated from the volume model and predicted to be 316 t C/ha and 1168 t CO2/ha at age 100.
Mortality of kauri in planted stands was as high as 3.9%/yr for individual stands, over their entire rotation to date. For all stands, mortality averaged 0.56%/yr. The highest mortality occurred in the years before the first assessment and averaged 0.64%/yr for all stands. From the first to the last assessment mortality averaged 0.30%/yr. Where mortality in individual stands was above the average rate the dominant cause was drought.
The growth and productivity of kauri in second-growth stands was only marginally improved by thinning to reduce competition. The volume removed in thinning operations had not been replaced in the (up to) 50 years since thinning treatments were applied. At age 150, the predicted height of kauri in unthinned control and thinned stands were identical at 25.9 m. Basal area at age 150 was 64.5 m2/ha in unthinned stands and 52.6 m2/ha in thinned stands. Whole-tree volume was predicted to be 681 m3/ha in unthinned and 549 m3/ha in thinned stands. Volume increment peaked at 5.2 m3/ha/yr in unthinned stands and 4.7 m3/ha/yr in thinned stands.
This study has shown that the worst growth and productivity of kauri in planted stands was better than that of the best natural stands. The difference in performance between plantation and second-growth kauri was most likely a result of a combination of lower site quality characteristics (soil type and fertility), stand structure and within-stand competition of natural stands.
The data for planted kauri came from 31 permanent sample plots located in 25 planted stands. These stands ranged in age from 14-83 years at the last assessment, and ranged in stand density from 218-1800 stems/ha. The overall number of planted stands and plots from which data was available to develop models was small in comparison to many exotic forest species datasets. The majority of the planted stands were not silviculturally treated after planting, and considerable variation in establishment methods was recorded. The results of productivity from the models developed for planted kauri should therefore be considered to be conservative.
The results of this study indicate an opportunity to grow kauri in plantations on good quality sites for the production of high quality sapwood timber over rotations of 60 years or less. They also indicate that second-growth stands will produce usable volumes of timber, but only over extended periods of time.
To ensure that kauri in planted stands can meet the potential observed during the development of these models, a series of well-managed stands on a range of sites is urgently required where the effects of timely silviculture, including initial stand density, can be assessed, quantified and reported on. Further research on selection and breeding for the species would improve the early establishment and growth of planted kauri resulting in a reduced rotation length. Research on long-term management strategies that include continuous cover forestry may make the species an attractive proposition for carbon forestry and/or for the production of high quality, naturally durable heartwood. The dataset compiled for this study was the best data available. While it cannot as yet be used to develop prescriptions for the establishment and maintenance of planted kauri stands, it does provide clues and directions that should be pursued in further research, however.
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Ingonyuluka ngelingafelwa nkonyane kwaMhlabuyalingana kwelaseMakhathiniNgubane, Caroline Ntombingaphi January 2013 (has links)
Submitted to the Faculty of Arts in fulfilment of the requirements for the Degree of Master of Arts in the Department of African Languages at the University of Zululand, South Africa, 2013. / Lolu cwaningo luveza ingonyuluka ngelingafelwa nkonyane kwaMhlabuyalingana,
umnotho kanye namasiko ale ndawo. Kubuye kubhekwe nemfuyo nokudla okuchuma
kule ndawo. = This research demonstrates the core idea of the fertile land of abundance of
KwaMhlabuyalingana, economy, culture and values of this area. Furthermore it also
looks at how livestock and crops flourish in this area.
Chapter one introduces the entire research and its aims. It also introduces the motive
behind the research itself. It also gives the research methods used to accomplish the
aims of the research and its scope of study generally. It also looks at who is going to
benefit out of the research. It also displays the division of chapters and the conclusion
of the first chapter.
Chapter two widely displays heritage and values found in this area: mountain ranges,
indigenous forests and rivers that beautify the area. In addition, it also gives types of
grass that easily adapt in the area which assist in curing ailments in people and help
them creating jobs through hand crafts. It also tells more about the types of crops that
are cultivated in the area of Makhathini like cotton, maize, beans, cane and vegetables
etcetera.
Chapter three explains more about indigenous fruits which are found in this place.
Where and when are found? What are they used for and how people benefit out of
these plants.
Chapter four deals with livestock. It looks at which livestock that can survive and
flourish in this area. How can it be used and its breeding and methods to care for so
that it can increase more. How to prevent them from different diseases during winter.
Farmers need to be advised and workshop as to how to take care of their livestock.
Chapter five deals with the analysis, recommendations and conclusion of the entire
research and winding up of the whole work done and recommendations to be taken
into consideration.
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