Coloradia pandora (Blake) is a phytophagous insect that defoliates Pinus ponderosa (Dougl. ex Laws.) in south-central Oregon. Little is known about the extent of damage this insect inflicts upon its host trees during an outbreak. In this paper, we present stem analyses on four dominant Pinus ponderosa trees that enable us to determine the amount of volume lost during each Coloradia pandora outbreak on this site for the past 450 years. We found that on average an outbreak inhibits radial growth so that an individual tree produces 0.057 m³ less wood volume than the potential growth for the duration of an individual outbreak. A total of 0.549 m³ of growth per tree was inhibited by 10 outbreaks during the lifetime of the trees, which, in this stand, equates to 9.912 m³/ha (1,700 board feet/acre) of wood suppressed over the last 450 years throughout the stand. Our results do not support previous findings of a lag in suppression onset between the canopy of the tree versus the base. Crossdating of stem analysis samples is paramount to definitively examine the potential for a lagged response throughout the

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Pacific silver fir (Abies amabilis (Dougl. ex Loud.) Forbes) is an important timber crop species in coastal forests of B.C. Its range extends from sea-level to almost timberline, and from the hypermaritime region on the west coast of Vancouver Island to the subcontinental region on the leeward side of the Coast Mountains. With this relatively wide climatic amplitude, a large variability in the height growth pattern of Pacific silver fir can be expected, since climate is considered to be the most influential determinant of the trajectory of height over age of forest trees. This variability, however, is not reflected in the height growth curves and site index tables used to estimate Pacific silver fir site index, since the curves and tables were developed from low-elevation stands on Vancouver Island. Consequently, when these curves and tables are applied to high-elevation or submaritime stands, we get biased estimates of site index. Accurate estimates of site index are necessary for accurate yield predictions. Furthermore, they are essential for making rational decisions about whether to cut the forest in situations where potential tree growth is marginal, such as in high-elevation forests.

Height growth models of coastal low- and mid-elevation Pacific silver fir, low-elevation white spruce, and low- and midelevation lodgepole pine have been used for predicting productivity of subalpine fir, Engelmann spruce, and lodgepole pine, respectively. These models, however, are biased in predicting height growth of high-elevation subalpine fir, Engelmann spruce, and lodgepole pine. To improve this situation, 329 sample plots (165 for subalpine fir, 90 for Engelmann spruce, and 74 for lodgepole pine) were located throughout the Engelmann Spruce-Subalpine Fir (ESSF) zone. Stem analysis was carried out on three dominant trees in each 0.04 ha sample plot. For each study species, a height growth model was developed on the data from two-thirds of the sample plots using the conditioned Chapman-Richards’ function; the model was validated using the remaining one-third of the sample plots.

Thesis (MScFor)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: Information on the external shape and internal properties of a tree such as the branch structure, tree ring widths and formation, and defects such as resin pockets is important for many forest –and wood science researchers as well as for the forest and wood processing industries. Resin pockets are internal defects associated with some softwood species, and are undesirable in some wood applications such as furniture and veneer. A tool that is often used in research to obtain this information is the Computed Tomography scanner. The high cost of the scanner, as well as the cost of transporting logs to the scanner, limits the application range of this equipment. An alternative, lower cost method would be beneficial for many researchers interested in tree shape and macroscopic internal tree characteristics. The objectives of this study were to: - Design, construct and test a mobile system that can be used in field to obtain a three‐dimensional model of a log or tree stem indicating selected macroscopic internal characteristics and, - Interpret results to explain the occurrence and causes of resin pockets in Pinus patula from the Mpumalanga escarpment, South Africa. A system for dissecting and measuring trees in field was designed, constructed and tested. The metal frame was used to cut a stationary, fixed log into discs and obtain digital images of crosssections along the stem axis. The frame was capable of processing logs with maximum dimensions of 3 m in length and 45 cm in diameter. Software was developed to convert the digital images into three‐dimensional models of logs and trees to demonstrate properties such as the external shape of the trees, branch structure and pith location. Properties such as ring width were measured from the images obtained. The study was conducted in the Mpumalanga escarpment to obtain three‐dimensional models of Pinus patula trees and to establish the reason for formation of resin pockets in these trees. Four 3 m logs from twenty‐four trees from three compartments were dissected and digitally reconstructed into three‐dimensional models. A total of 61 cross sections with resin pockets were identified from the 2750 cross cut images taken 20 cm apart along the longitudinal axis of the log. It was not possible to accept or reject conclusively any of the existing hypotheses for the cause of resin pocket formation. The formation of Type 2 resin pockets was most probably due to felling damage during thinning operations. It seems likely that wind damage and possibly insects might be responsible for the formation of Type 1 resin pockets. / AFRIKAANSE OPSOMMING: Kennis in verband met die interne eienskappe van ‘n boom soos takeienskappe, jaarringwydte en vorm, en harsholtes is belangrik vir sommige bos ‐en houtkundige navorsers. Die toerusting wat huidiglik algemeen gebruik word om inligting van hierdie aard te bekom is ‘n CT skandeerder. Die metode is egter duur as gevolg van hoë kapitale koste van die toerusting sowel as die vervoerkoste van stompe na die CT‐fasiliteit. ‘n Meer ekonomiese alternatief sal vir baie navorsers van waarde wees. Harsholtes in hout lei tot afgradering van hout en fineer. Die doel van die studie was twee‐sydig: - Om ‘n stelsel te ontwerp en bou wat ‘n drie‐dimensionele model van ‘n boom kan skep wat sommige makroskopiese, interne eienskappe weergee, en - Om die voorkoms en oorsaak van harsholtes in Pinus Patula van die Mpumalanga platorand te ondersoek. ‘n Raam is ontwerp en vervaardig wat in die plantasie gebruik word. Die raam kan stompe van tot drie meter lengte met ‘n maksimale diameter van 45 cm hanteer. Die raam is gebruik om snitte deur die stompe te maak, ‘n afstandmeting tot by die gesaagde oppervlak word deur ‘n lasermeter geneem en ‘n kamera neem ‘n foto. Sagteware word dan gebruik vir die uitkenning van sekere dele in elke beeld sowel as die samestelling van ‘n drie‐dimensionele model. Data‐insameling met die raam is in Mpumalanga gedoen. Die raam is in die tydperk getoets en het goed gefunksioneer. Vier stompe elk vanaf vier‐en‐twintig bome vanuit drie afsonderlike kompartemente is verwerk op die raam en volledige drie‐dimensionele modelle geskep vir hierdie bome insluitend hul eksterne vorm, takeienskappe en pitvorm (“pith location”). Ongeveer 2750 foto’s van dwarssnitte is tydens data‐insameling geneem. Net 61 van die foto’s het harsholtes bevat. Geen definitiewe oorsaak van harsholtes kon bepaal word nie. Tipe 2 harsholtes word waarskynlik as gevolg van skade tydens uitdunning van bome gevorm. Wind en insekte lyk na die mees waarskynlike oorsake van Tipe 1 harsholtes.

At the present work it was studied growing of Nectandra megapotamica (Spreng.) Mez species, through a sampler compounded by 11 dominant trees selected from rainforest in Nova Prata borrough, state of Rio Grande do Sul. The growth of the sampler trees can be give up successfully through steam analysis determ the growth trend in percentual volume along time, for the selected trees. The mathematical model better represents the growth trend in percentual volume was described as iv%=(b0+b1.ln dap)2, fitting individually per tree. Covariance analysis earn possible to cluster three groups, contends trees with decreasing trend were similar in relationship to trend and curves level, being possible to describe this variations with mathematical models using independent factors, as: morphomety, competition and environmental from the trees in case, by expressions : b1 = 0,41738583 + 4,16179208.id5 - 6,29332107.h/d + 0,37822636.EXPOS - 0,11519372.Ir + 5,80418708.BALcor 0,06858050.Lc, with determination coefficient equal to 0,9979 and variation coefficient of 1,73%, as well as the differences between curves levels by equation b0 = 2,62465943 13,37023979.id5 + 22, 08329412.h/d 1,33160878. EXPOS + 0,34688547.Ir 23,88899208.BALcor + 0,25692291.Lc, with determination coefficient fitting on 0,9907 and variation coefficient of 2,71%. / No presente trabalho, foi estudado o crescimento da espécie Nectandra megapotamica (Spreng.) Mez através de uma amostra composta por 11 árvores dominantes, selecionadas em Floresta Ombrófila Mista, no município de Nova Prata-RS. O crescimento das árvores amostradas pôde ser reconstituído com sucesso por meio da análise de tronco, determinandose a tendência do crescimento em volume percentual ao longo do tempo, para as árvores selecionadas. O modelo matemático que melhor representou a tendência de crescimento em volume percentual foi descrito como iv%=(b0+b1.ln dap)2, ajustado por árvore individual. A análise de covariância possibilitou a formação de três grupos contendo árvores com tendência decrescente semelhantes entre si, em relação à tendência e nível das curvas. Tornou-se possível descrever estas variações com modelos matemáticos utilizando-se variáveis independentes de morfometria, concorrência e ambientais, das árvores estudadas, pelas expressões: b1 = 0,41738583 + 4,16179208.id5 - 6,29332107.h/d + 0,37822636.EXPOS - 0,11519372.Ir + 5,80418708.BALcor 0,06858050.Lc, com coeficiente de determinação ajustado igual a 0,9979 e coeficiente de variação de 1,73%, bem como as diferenças entre níveis das curvas pela equação b0 = 2,62465943 13,37023979.id5 + 22,08329412.h/d 1,33160878.EXPOS + 0,34688547.Ir 23,88899208.BALcor + 0,25692291.Lc, com coeficiente de determinação ajustado de 0,9907 e coeficiente de variação igual a 2,71%.