The objectives of this study were to study wood property variation in Pinus patula from different physiographic sites, the interrelationship between wood properties and the effects of some forest site factors on wood properties and their within-tree variation. The wood properties considered were density, transverse shrinkage, grain angle and stiffness (modulus of elasticity). Ten trees were taken from each of seventeen sites selected during a previous study of soil ecology and tree growth patterns on the escarpment of Mpumalanga in South Africa. This is a complex physiographic region with several different growth sites within a relatively small geographical area. The key finding of the study was that the effect of radial distance from the pith (i.e. the age of the tree) was highly significant and accounted for most of the variation of the trees sampled. Although the effect of site on the selected wood properties was highly significant, its effect accounted for a relatively small percentage of the total variation in each case. Consequently, solid wood processors must take into account the large variation within a tree when implementing strategies to minimise the downgrade of timber as result of excessive board distortion and/or inferior strength. There were significant correlations between wood density and density slope, radial shrinkage, shrinkage ratio and stiffness and also significant correlations between wood stiffness and density slope and radial shrinkage. Density and grain angle both showed significant correlations with the most important climatic factors. ‘Growth days’ (which is an index reflecting the number of days per year when soil moisture is not a limiting factor for plant growth) was identified as one of the principal growth factors influencing the selected wood properties, because of it’s strong relationships with wood density, density slope, grain angle and stiffness. Regression models were developed to predict wood density and grain angle from growth variables. The results show that those wood properties that correlate with geographic representable site variables can be included in site classification and evaluation systems, to assist in predicting growth in terms of volume yield and wood quality.

Due to the opportunity for afforestation in South Africa being severely limited, extensive research is being carried out on obtaining more wood per given area, improving the quality and value of the wood and on gaining a better understanding of how wood properties influence the characteristics of the pulp it produces. The last mentioned is the main focus of this study. If the variations in pulp, due to variations in wood properties, are better understood, then the existing fibre resource could be more efficiently managed and utilised to maximise its value. The main objective of this study was to determine how variation in physical and chemical properties, from the existing P.patula resource drives variation in pulp strength properties. It is well known that differences in tree age and site index lead to major sources of variation of various wood properties. These two easily measured variables were used in this study to capture a significant amount of variation in the wood of the aforementioned genus that enters a mill. Samples were obtained from two extremes in site quality, as measured by site index, (viz. good and poor sites) and three age ranges (viz. 9-10 years, 13-14 years and 20-21 years) from the KwaZulu-Natal Midlands. Wood chips from each of the six sites were pulped for various lengths of time, using the Kraft pulping method and under the same pulping conditions. A wide range of anatomical and chemical properties of wood and pulp were measured to characterise these samples as extensively as possible. All pulp samples were beaten in a PFI mill, at four different levels. The freeness values of the beaten samples were measured. The physical properties measured on handsheets made from the pulp included sheet density, burst index, tear index, tensile index, tensile energy absorbed, stretch and zero-span tensile strength. Regression models were developed to quantify the impact of the measured variables on each of the strength properties. Principal component analysis was performed on the wood characteristics measured and indicated that tree age is a more critical source of variation in wood properties than site index. The predictions of whole tree wood properties from the properties measured at breast height were excellent. Pulping studies showed that pulp yield, at kappa 20-30, increased with tree age. Wood cellulose proved to be a very good predictor of pulp yield. Xylose and mannose appeared to be most resistant to degradation during pulping. The low yield pulps were easier to refine than those with high yield. This has important implications when considering high yield pulping processes. With regard to pulp strength, the younger material could not achieve the high tear strengths obtained by the older material. However, the tear strengths achieved by these younger sites were comparable with, if not higher than, that obtained by hardwood species. The implications of this is that younger P. patula trees could be used for grades of paper where very high tear strength is not essential, but tensile is (e.g. tissue paper) and that older material can be better used for the purpose of providing the high tear strength needed by certain paper grades (e.g. linerboard and sackkraft). The maximum tensile strength achieved by the younger material was higher than that of the older material. When compared at constant freeness or sheet density, longer cooking times had a deleterious effect on strength properties. Strong predictions of pulp strength from basic wood properties were obtained when strength results were compared at constant freeness and sheet density. Because of the great influence of fibre morphology and chemistry on refining rates and on the resultant strength properties, the results of the study suggest that fibres of greatly different chemical and anatomical characteristics should not be refined together, if beating energy and pulp strength are to be optimised. However, further work is required to evaluate if the separation of fibre resources, to improve pulp quality, would be economically viable. / Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2005.

A study of factors contributing to successful controlled pollinations of Pinus patula Scheide et Deppe was undertaken. The pollen morphology of P. patula, P. oocarpa, P. greggii, P. elliottii, P. tecunumanii, P. caribaea and P. radiata was studied and the mean size of pollen grains was determined for these species. Clonal differences in pollen size within P. patula were also determined. The impact of pollen management practices on pollen viability was highlighted and a protocol for in vitro pollen viability testing of P. patula and other pine species was determined. A one percent agar solidified distilled water medium gave the best germination results after 72 hours incubation at 30 °C for a number of different Pinus species and P. patula clones. The addition of boric acid increase germination, although not significantly. The addition of sucrose to the pollen germination medium had a negative effect on pollen germination of P. patula, P. greggii and P. caribaea. Re-hydration of pollen for two hours prior to in vitro germination testing improved germination significantly. Incubation temperatures of above 38 °C were detrimental to germinating pollen grains. Stored pollen with low humidity (less than 10 %) of P. patula, P. greggii and P. caribaea could tolerate temperatures of up to 70 °C while still retaining some level of viability. The initiation and growth of the pollen tube was also studied and differences in pollen tube-lengths germinated at 30 °C for 72 hours were found between species studied. Flowering of different P. patula clones was monitored over seven seasons. Flowering periods varied in length between 4 and 14 days amongst five clones over the different seasons. The best cone-survival after controlled pollination was achieved with breathable micro-fibre material. Seed yields were also highest when breathable material was used for controlled pollination. The role of pollen viability in controlled pollination was also determined in pollination studies with low viability resulting in low cone survival and low seed yields. The temperature and relative humidity inside isolation bags were monitored and temperatures above 40 °C were reached inside bags constructed of nonbreathable material. These temperatures were lethal to pollen germinating in vitro. Relative humidity of between 80 and 100 % was maintained in non-breathable bagging material, constituting a risk of diseases causing cone-mortality. The application of fungicide before, during and after controlled pollination was ineffective in improving cone survival. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 2002.

Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy Faculty of Science University of Witwatersrand Johannesburg SOUTH AFRICA / A three-year study was undertaken In the province of Mpumalanga, South Africa to Investigate the competitive effects of the grass Setaria megaphylla on the growth of the tree species Pinus patula. A replacement series field trial, where six different competition regimes were Implemented, clearly demonstrated the suppressive effects of S. ( Abbreviation abstract ) / AC2017

A thesis submitted in the Faculty of Science, University of Witwatersrand, Johannesburg for the degree of Doctor of Philosophy. Johannesburg, 1996. / Litter accumulates on the forest floor in Pinus patula plantations in Mpumalanga, South Africa and as a result nutrients become immobilized and site productivity is reduced. Studies have correlated litteraccumulation with abiotic factors, such as high altitude sites, high rainfall soils derived from the timeball series (shale) have thick litter layers. This study focuses on the biotic factors involved in litter accumulation. [Abbreviated Abstract. Open document to view full version] / GR 2017

The largest area of commercial timber plantations in southern Africa is situated along the Eastern Transvaal Drakensberg Escarpment north of Nelspruit. The site requirements of tree species in this area are poorly understood. The purpose of this study was to examine site-tree relationships in the region and the implications of such relationships for the science of forestry. Pinus patula Schiede & Deppe in Schlecht. & Cham. was selected for the study as it is the most widely planted species in the region. In Chapter 1 the geology, geomorphology, climate, soils and vegetation of the study area are described. A geological map was compiled. Soil descriptions were based on 439 soil pits distributed so as to cover the range of site conditions in the area. The regression techniques used to identify key environmental factors and to model their relationships with tree parameters are described in Chapter 2, in which site-growth relationships specifically are investigated. In mature stands of P. patula 159 plots were established in such a way as to cover the widest variation in both site conditions and tree growth. The relationship between site index (mean top height at 20 years) and 100 site plus 10 stand parameters recorded at each plot was modelled by means of best-subsets, multiple and ridge regression. Several candidate models were compared on the basis of coefficient of determination and validation using independent data. The best model predicted the site index of the validation plots within 60 cm of the measured site index. The possible roles of the site variables identified by the models are discussed. In Chapter 3 site-foliar nutrient relationships are described. A close relationship was found between foliar and soil nutrient levels for the six major geological substrates. Site index was more accurately predicted from concentrations of individual foliar nutrients than from ratios of these nutrients. The Diagnosis and Recommendation Integrated System (DRIS), however, appeared to have greater potential for nutrient diagnosis. Provisional ORIS norms for P. patula were computed. In Chapter 4 the excessive accumulation of litter in P. patula stands was examined. Undecomposed litter layers were greater than 15 cm in thickness on nearly 25% of the 159 sites studied. Average litter layers contained greater amounts of nutrients than the underlying topsoil. Due to the colonization of the litter by tree roots, the degree of immobilization of nutrients in litter is not known. Environmental factors associated with variation in litter thickness were identified by models which explained up to 73% of the total variation. These factors are considered to act indirectly by promoting or retarding decay organisms. The possible implications of litter accumulation for the maintenance of site productivity are discussed. In Chapter 5 relationships between site and some wood properties are described. Although between-tree variation was larger than between-site variation, some important relationships with site were identified. 10% of all trees on the 159 plots had severe stem bumps. Most of the variables in a model to predict the severity of bumps could be interpreted as being associated with stem stability or exposure. The conclusion was that wind is probably the major cause of this defect. The findings of the study are summarized in Chapter 6. Particular attention is given to a synthesis of the possible roles of site factors in their relationships with the tree parameters investigated. There were strong relationships between tree parameters and mainly rainfall, altitude, soil wetness, exchangeable bases, effective rooting depth, slope position and geology. The single most deficient nutrient element appeared to be calcium. The implications for both research and management are outlined. / Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 1990.

Summary: The future mass propagation of elite families of Pinus patula by cuttings is a realistic method of deployment if the short-term performance of cuttings and seedlings are confirmed at harvesting. This will impact significantly on the future outlook of forestry in South Africa as softwood yields are improved substantially through the introduction of material of high genetic value in commercial plantings. This, however, will require significant changes in future silviculture and other management practices as foresters and plantation staff learn to regenerate, maintain, and schedule the harvesting of cutting stands according to a different set of demands as a result of the change in plant type. Contrary to operational experience, cutting survival was similar to seedling survival in all field studies. This indicates that factors other than those that were studied and reported on, such as planting techniques, may be contributing to mortality. Also, due to the different root structure of cuttings they may be more fragile. The similar survival observed in these trials, therefore, may have been due to the close supervision given to the planting operations by the research staff. Although survival was similar, both plant types survived unacceptably poorly in the majority of studies with an average stocking of approximately 50% at one year. It is therefore anticipated that commercial stands will require several blanking operations in order to achieve an acceptable stocking in excess of 85% by the following planting season. The reduction in expected profitability as a result of blanking costs, delayed establishment, and the loss of improved genetic plant material, indicates that this is an area that still requires further research irrespective of what plant type is being planted. The pathogen, Fusarium circinatum, was commonly isolated from the planting stock before and after planting in two studies. Due to its virulent nature, it was assumed that mortality on the trees on which F. circinatum was isolated was principally due to this pathogen. At planting all plants were observed to be healthy and free of disease indicating that this pathogen maybe carried from the nursery to the field in a cryptic form, either inside or outside the plant tissue , which results in the death of the newly planted tree. In two field studies, where F. circinatum was commonly isolated, the application of Benomyl fungicide and to some extent the biological control agent Trichoderma harzianum at planting appeared to improve survival although this improvement was not significant. Laboratory studies, designed to determine alternatives to Benomyl fungicide, indicated that three fungicides (Octave, Folicur and Tilt), three sterilants (Sporekill®, Prasin®and Citex®) , as well as a biological control agent (T.harzianum), were all highly successful in controlling F. circinatum colony growth in vitro. It is recommended that these products undergo nursery testing , where the plant material is inoculated with F. circinatum spores, in order to test their efficacy and possible phytotoxicity in vivo before commercial application. Post-planting survival was also affected by site climate . Greater temperature extremes, as well as lower humidity and less rainfall resulted in poor survival. Plant dimension at planting was found to interact with site quality where it was a significant factor on a poor quality site. Optimal cutting dimensions at planting was a root collar diameter of 2.8 - 3.2 mm, and a stem height greater than 7 cm at planting for cuttings produced in cavities 90 ml in volume. Optimal seedling dimensions at planting were a root collar diameter of 1.8 - 2 mm, and a stem height of 10 - 15 cm for seedlings produced in cavities 80 ml in volume. In a separate study, plant morphological criteria influenced medium-term growth, where greater root mass and thicker cutting root collar diameters at planting improved field growth performance for seven years after planting. A greater root mass at planting was achieved by raising cuttings in containers that could support greater medium volume. From the study it was concluded that cuttings should be raised for an approximate period of 9 months in container cavities no smaller than 80 ml in volume and possess an oven-dry root mass of 0.3 - 0.5 g at planting. In addition to similar survival, the cuttings in this study grew either similarly to, or in some cases out-performed, the seedlings that were used as a control. Several other published studies indicate that hedge maturation poses the greatest threat to the success of softwood cutting deployment. This is especially true in clonal forestry and methods to maintain juvenility, such as cold storage of shoots and cryopreservation, require further research before clonal plantations of P. patula can be realised. In the studies carried out on family hedges in this report, the effect of donor hedge maturation was found to influence nursery management practice and the characteristics of rooted cuttings. The nursery data indicates that rooting efficiency, root system quality, and stem size and form, all decline with increasing hedge age particularly from two years after the date of sowing. A decline in root system quality was particularly apparent and was observed prior to a decline in rooting efficiency. If field trials indicate poorer performance from older hedges , it may be necessary to determine whether the causes are purely ontogenetic, morphological, or both before drawing final conclusions about hedge longevity. Until such results are known, it is recommended that P. patula cuttings should be propagated from seedling donors maintained as hedges , approximately 15 cm high, for a period not more than three years from the date of sowing. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2005.

Thesis (MScFor (Dept. of Forest and Wood Science)--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: In this study 1345 pieces of 38x114 mm timber sawn from 16-20 year-old Pinus patula trees were obtained from a wide variety of sites along the Mpumalanga escarpment in South Africa. The samples were tested for various mechanical and physical properties. The objectives of this study were (1) to determine the variation in the bending strength, tension strength, and stiffness of the sawn timber, (2) to assess the efficiency of the current visual and mechanical grading rules on this sample, and (3) to evaluate the potential of some indicator properties to be used as structural grading parameters on this resource. A large number of non-destructive measurements were performed on all the samples, including scanning of the boards with a commercial X-ray density scanner, moisture content measurement, growth ring measurements, warp measurement, acoustic frequency measurement and measurement of the stiffness using a mechanical grader. The data from the X-ray density scanner was used to calculate a number of knot-related variables for each board. Visual grading according to the SANS 1783-2 (2005) specifications for structural timber was performed by a certified grader on all the boards. The timber was divided into two groups for destructive testing, one group each for bending and tension tests. Tests were conducted according to the SANS 6122 (1994) method for in-grade testing. Due to the sampling method followed, the destructive tests effectively used a random placement of defects with regard to the load application position. From the destructive tests the modulus of elasticity (MOEedge), bending strength (MOR) and tensile strength were determined. The study showed that the MOEedge of the sawn timber was far below the requirements of the current national standard (SANS 10163-1) for all of the visual and mechanical grades. The mean MOEedge of the visually graded S5 timber was about 30% lower than required. The 5th percentile values for bending strength of all the visual and mechanical grades were above the required values of SANS 10163-1. The 5th percentile values for tensile strength of all the visual and mechanical grades were similar to that required by the SANS 10163-1 standard. Correlations between flatwise measured MOE (MOEflat) and edgewise measured MOE (MOEedge) were smaller than expected, as well as the correlations between both MOEedge and MOEflat with MOR. Dynamic MOE (MOEdyn), calculated from acoustic frequency tests on the timber, was found to be the best single predictor of MOEedge, MOR and tension strength. Multiple regression analysis showed that a combination of MOEdyn, density and knot parameters can be used to improve the predictability of some of the strength and stiffness characteristics of the timber. It is recommended that a comprehensive study on the structural grading of SA Pine be performed which includes (1) an analysis of market requirements in terms of strength and stiffness properties of timber, (2) in-grade testing of a representative sample of structural timber in South Africa, and (3) a review of the standards used in South Africa to regulate the structural grading of timber. / AFRIKAANSE OPSOMMING: In hierdie studie is 1345 stukke 38x114 mm 16-20 jaar-oue Pinus patula planke, afkomstig van ‘n wye verskydenheid groeiplekke teen die Mpumalanga platorand in Suid Afrika, gebruik. Die planke is getoets vir verskeie meganiese sowel as fisiese eienskappe. Die doelwitte van hierdie studie was om (1) die variasie in buigsterkte, treksterkte en styfheid van die gesaagde planke te bepaal, (2) die effektiwiteit van die huidige visuele -en meganiese graderingsreëls op hierdie monster planke vas te stel, en (3) die potensiaal te evalueer van sommige eienskappe wat gebruik kan word as strukturele graderingsparameters. ‘n Groot hoeveelheid nie-destruktiewe toetse is op alle planke uitgevoer, wat ingesluit het skandering van planke met ‘n kommersiële X-straaldigt-heidskandeerder, metings van voginhoud, groeiringwydtes, deformasie, akoestiese frekwensie en die bepaling van styfheid met behulp van ‘n meganiese gradeerder. Die data van die X-straalskandeerder is gebruik om ‘n aantal kwasverwante veranderlikes vir elke plank te bereken. Visuele gradering is op alle planke uitgevoer ooreenkomstig met die SANS 1783-2 (2005) spesifikasies vir strukturele hout deur ‘n gesertifiseerde gradeerder. Die hout is in twee groepe opgedeel vir destruktiewe toetse, een vir buigtoetse en een vir trektoetse, ooreenkomstig met die SANS 6122 (1994) metode vir binnegraadse toetse. As gevolg van die monsternemingsmetodiek wat gevolg is, is daar effektief gebruik gemaak van ‘n lukrake plasing van defekte met betrekking tot die las-aanwendingsposisie. Die modulus van elastisiteit (MOEedge), buigsterkte (MOR) en treksterkte is deur middel van destruktiewe toetsresultate bepaal. Die studie het aangetoon dat die MOEedge van gesaagde hout aansienlik minder as die vereiste van die huidige nasionale standaard (SANS 10163-1) is vir al die visuele en meganiese grade. Die gemiddelde MOEedge van die visueel-gegradeerde S5 planke was omtrent 30% laer as vereis. Die 5de persentiel waardes vir buigsterkte van alle visuele en meganiese grade was hoër as die vereiste waardes soos voorgeskryf deur SANS 10163-1. Die 5de persentiel waardes vir treksterkte van alle visuele en meganiese grade was gelykstaande aan wat vereis word deur SANS 10163-1. Korrelasies tussen MOE, gemeet op die wydte sy (MOEflat), en MOE, gemeet op die diktesy (MOEedge), asook die korrelasies van beide MOEedge en MOEflat met MOR van die planke was laer as verwag. Dinamiese MOE (MOEdyn), wat bereken was vanaf die akoestiese frekwensie resultate, is vasgestel as die beste enkele indikator van MOEedge, MOR en treksterkte. Meervuldige regressie analise het aangetoon dat ‘n kombinasie van MOEdyn, digtheid en kwasparameters gebruik kan word om die voorspelbaarheid van sommige van die sterkte- en styfheids eienskappe van die hout te verbeter. Daar word aanbeveel dat ‘n omvattende studie gedoen word op die strukturele gradering van SA Dennehout, wat insluit (1) ‘n analise van die markbehoeftes in terme van die sterkte- en styfheids eienskappe van hout, (2) binnegraadse toetsing van ‘n verteenwoordigende monster strukturele hout in Suid Afrika, en (3) die hersiening van standaarde in gebruik in Suid Afrika om die strukturele gradering van hout te reguleer.

Thesis (MScBosb)--University of Stellenbosch, 2004. / ENGLISH ABSTRACT: The characteristics and total fuel load of the forest floor (FF) and harvest residue (HR) are needed to develop tools that can be used for fuel load management, fire risk analysis and fire behaviour prediction for P. patula grown in the summer rainfall area of South Africa (SA). Forest floor depth, mass and ash-free mass were measured and there was generally a greater range in depth under sawtimber (ST) stands than under pulpwood (PLP) stands. Forest floor loads, prior to ashing, ranged from 21 - 168 t ha-1 and 27 - 72 t ha-1, for ST and PLP stands, respectively and loads increased linearly with stand age. Sawtimber and PLP stands were analysed together, which resulted in a significant correlation between depth and mass (r2 = 0.78, n = 31). A loss on ignition procedure carried out on sub-samples of the FF improved the relationship between the FF depth and the ash-free mass for the different stands, and provided a more accurate model for the prediction of mass from depth. A multiple regression analysis revealed that age, altitude and mean annual precipitation (MAP) provided the best subset and accounted for 72% of the variation in the FF mass observed. The effect of increasing FF load and increasing moisture content on the fireline intensity (FLI) was examined using the fire behaviour prediction programme, BehavePlus. Harvest residue was quantified and characterised in terms of fuel size classes, under current silvicultural regimes for ST and PLP, for the development of fuel models for this species over its planted range in SA. An investigation into the proportion (by mass) of the 1- (0.0 - 0.6 cm), 10- (0.6 – 2.5 cm), 100- (2.5 – 7.6 cm) and 1000-hr (> 7.6 cm diameter) fuel classes of the total HR mass indicated that there was a significant difference between the mass of the 1-, 10- and 1000-hr fuel classes of the two silvicultural regimes, and no significant difference for the 100-hr fuel class. Two fuel models for P. patula HR and two models for standing timber were developed using the new model (NEWMDL) programme of BEHAVE and tested in BehavePlus. Nutrient concentrations were used with FF layer and HR size class load data to estimate the quantities of nutrients held in the fuel and to describe nutrient distributions in the fuel complex. Significant differences in the nutrient concentration of the FF layers and fuel components were observed which has important implications for fuel management. The concentration of N determined in this study, relative to that determined in other similar studies on P. patula was low. Forest floor loads were predicted and nutrient pools calculated for typical ST and PLP stands at both low and high altitude to provide insight into the nutrient distributions within the fuel complex. / AFRIKAANSE OPSOMMING: Die karaktereienskappe en totale brandstoflading van die bosvloer (FF) en kaalkap oorskot (HR) word benodig om instrumente te ontwikkel wat gebruik kan word vir brandstoflading bestuur, brandgevaar ontleding en brandgedrag voorspelling vir P. patula, wat in die somer reënvalgebied van Suid-Afrika groei. Die bosvloer diepte, massa en asvrye massa is gemeet en daar was oor die algemeen ‘n groter variasie in diepte onder saaghout (ST) opstande as onder pulphout (PLP) opstande. Die bosvloerladings, voor verassing, het varieer van 21 – 168 t ha-1 en 27 – 72 t ha-1 vir ST en PLP opstande respektiwelik. Ladings het linieêr vermeerder met opstand ouderdom. Saaghout en PLP opstande is saam geanaliseer en het tot ‘n betekenisvolle korrelasie gelei tussen diepte en massa (r2 = 0.78, n = 31). ‘n Verliestydens- ontbranding prosedure is uitgevoer op die FF monsters en het die verhouding tussen FF diepte en die asvrye massa van die verskillende opstande verbeter. Dit het ook gelei tot akkurater model vir die voorspelling van massa vanaf diepte. ‘n Veelvoudige regressie analise het aan die lig gebring dat ouderdom, hoogte en gemiddelde jaarlikse reënval (MAP) die beste sub-groep verskaf, en het 72% van die variasie in die FF massa verklaar. Ondersoek is ingestel op die effek van toenemende FF lading en toenemende voginhoud op die brandlyn intensiteit (FLI) deur die brandgedrag program, BehavePlus, toe te pas. Die kaalkap oorskot is gekwantifiseer en gekarakteriseer volgens brandstof grootteklasse, onder die huidige boskultuurstelsels vir ST en PLP, vir die ontwikkeling van brandstofmodelle vir hierdie spesie oor die betrokke groeistreek in SA. ‘n Ondersoek in die verhouding (volgens massa) van die 1- (0.0 – 0.6 cm), 10- (0.6 – 2.5 cm), 100- (2.5 – 7.6 cm) en 1000-uur (> 7.6 cm deursnee) brandstofklasse van die totale HR massa het aangedui dat daar ‘n betekenisvolle verskil is tussen die massas van die 1-, 10- en 1000-uur brandstofklasse van die twee boskultuurstelsels, en geen betekenisvolle verskil vir die 100- uur brandstofklas nie. Twee brandstofmodelle is ontwikkel vir P. patula HR en twee modelle vir staande hout deur gebruik te maak van die nuwe model (NEWMDL) program van BEHAVE en getoets in BehavePlus. Voedingstof konsentrasies is gebruik, tesame met die FF laag en HR klasgrootte ladingdata, om die voedingstof inhoud van die brandstof te skat en om die voedingstof verspreiding te beskryf in die brandstofkompleks. Betekenisvolle verskille is waargeneem in die voedingstof konsentrasies van die FF lae en brandstof komponente wat belangrike implikasies inhou vir brandstofbestuur. Die konsentrasie wat vir N in hierdie studie bepaal is, was laag relatief tot ander soortgelyke studies vir P. patula. Die bosvloer ladings is voorspel en voedingstofpoele bereken vir tipiese ST en PLP opstande vir beide lae en hoë hoogtes om insig te verkry, sodat insig verkry kon word in die voedingstof verspreidings binne die brandstofkompleks.