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The form factors of South African trees: is it possible to classify them easily using field measurements and photographs?Muzite, Tapiwa January 2017 (has links)
A research report submitted to the Faculty of Sciences, University of the Witwatersrand, Johannesburg in partial fulfilment of the requirements for the degree of Masters of Science in Environmental Sciences, 2017 / Modern tree biomass allometry makes use of “form factor”, which is the ratio of the true volume to the apparent volume. However, there is no database of form factors of South African trees, hence this study was undertaken to assess the possibility of assigning form factors to trees in a quick and easy way, either by visual assessment of an image of the tree or by simple field measurements. Stem diameter, taper and node length data for 112 trees was collected using both in situ and in-lab measurements from photos taken of the same trees in the field. The data were used to model tree volume using the fractal properties of branching architecture. The estimated tree volume was then used along with basal diameter and tree height to calculate the form factor.
Results showed that measurements taken off images underestimated stem diameter and node length by 4% and 5% respectively, but the fractal allometry relationships developed using either the manual in-field or image analysis approach were not statistically different. This proves that dry season photography is sufficiently accurate for establishing relationships needed to construct a fractal model of tree volume. The image analysis approach requires a clear unobstructed view of the sample tree. This requirement made the approach less effective as when trees were in close proximity and when branches overlapped. The time taken using the photographic approach was twice the amount taken for the manual in-field.
Form factor varied between species, but the variation was not statistically significant (p=0.579). The mean form factor per species ranged from 0.43 to 0.69. Form factors were negatively correlated with wood density (-0.177), basal diameter (-0.547) and height (-0.649). Due to the unavailability of an independent tree biomass dataset, it was impossible to validate the allometric equations based on estimated form factors and wood density. The inclusion of form factor was shown to improve the accuracy of biomass estimation by 11%.
Principal component analysis showed that form factors can be assigned using tree height and the form quotient. / XL2018
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Letter from C.J. Skead to Mr. F.C. MetrowichSkead, C J (Cuthbert John) January 1959 (has links)
Letter written by C.J Skead to Mr. F.C. Metrowich, authot of "The valiant but once". In the letter Skead submits a request for references indicating where the inforamtion was obtained as to the tree where Lieut. Col. Graham and Capt. Stockenstrom decided to establish the town of Grahamstown.
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Letter from Mr. F.C. Metrowich responding to C.J. SkeadMetrowich, F C (Frederick Charles) 06 June 1959 (has links)
Letter written by Mr. F.C. Metrowich to C.J Skead. This letter was in response to a letter sent by Skead requesting for references indicating where the information was obtained as to the tree where Lieut. Col. Graham and Capt. Stockenstrom decided to establish the town of Grahamstown.
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Acacia caffra in winterSkead, C J (Cuthbert John) 06 1900 (has links)
Caption "Acacia caffra leafless in winter. June 1961. Below Laing Dam.”
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Old tree 'chopped' by age and insectsMatthews, Ray 24 November 1969 (has links)
Newspaper article: "Old tree chopped by age and insects. Age and insects have put and end to one of Maritzburg's national monuments. An acacia mimosa tree that stood in the centre lawn of the Parkside home of the Administrator of Natal since about 1800, has been chopped down for safety reasons. The stately old tree was National Monument and the plaque on the stump reads: Monuments Commission. Around this tree, Commandant A. W. J. Pretorius, member of the Volksraad and the Burgers of the Republic Natalia decided by a majority on July 5, 1842, to accept British rule.”
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Acacia robusta - Kei BridgeSkead, C J (Cuthbert John) 10 1900 (has links)
Caption "Acacia robusta in flower at Kei Bridge. Oct. 1963.”
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Acacia Karoo enormous thornsSkead, C J (Cuthbert John) January 1958 (has links)
Caption "Enormous thorns on type of A. Karoo found in Fish River Bush near Grahamstown. 1958.”
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Acacia tortilis near KimberleySkead, C J (Cuthbert John) 04 1900 (has links)
Caption "Acacia tortilis (heteracantha) 15 m. west of Kimberley on the Schmidstdrif road. A typical tree there. Very sharp, hooke thorns. April 1959.”
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Elizabeth Salt Monument in High Street (Grahamstown)Skead, C J (Cuthbert John) January 1900 (has links)
Elisabeth Salt Monument, High Street, Grahamstown, South Africa, commemorating the Xhosa-British battle of 22 April 1819. It was built in memory of the pioneer woman in the Battle of Grahamstown. In 1819 Xhosa’s attacked the settlement with about 6 000 men. Many of the warriors died during the battle but only 2 British. According to legend Elizabeth salt carried a keg of gunpowder through the Xhosa warriors to the men by wrapping it in a baby blanket. This story is shown on the plaque on the monument. The monument also marks the spot where, under a tree, Lieutenant Colonel Graham and Captian Stockenstrom decided on the site for Grahamstown. They camped on the land where the cathedral stands today. The town was proclaimed in August 1811 and was named after Colonel John Graham.
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Elizabeth Salt Monument in High Street (Grahamstown)Skead, C J (Cuthbert John) January 1900 (has links)
Elisabeth Salt Monument, High Street, Grahamstown, South Africa, commemorating the Xhosa-British battle of 22 April 1819. It was built in memory of the pioneer woman in the Battle of Grahamstown. In 1819 Xhosa’s attacked the settlement with about 6 000 men. Many of the warriors died during the battle but only 2 British. According to legend Elizabeth salt carried a keg of gunpowder through the Xhosa warriors to the men by wrapping it in a baby blanket. This story is shown on the plaque on the monument. The monument also marks the spot where, under a tree, Lieutenant Colonel Graham and Captian Stockenstrom decided on the site for Grahamstown. They camped on the land where the cathedral stands today. The town was proclaimed in August 1811 and was named after Colonel John Graham.
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