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Syrah is an important wine grape in California but is potentially difficult to manage in the vineyard due to its excessive vigor. Vigorous grapevines require more labor for canopy management and tend to create excess shade, decreasing fruit quality. Winter pruning level, shoot thinning and leaf removal influence the overall density of the canopy and the subsequent degree of shade in the fruit zone. An experiment was conducted to assess the effects of two pruning levels with three degrees of labor-intensive canopy management techniques on berry maturation rate and harvest berry parameters for two growing seasons. In 2008, repeated measures analysis showed no significant effects of severe pruning, shoot thinning or both sides leaf removal on maturation rate of performance indicators. At harvest 2008, severe pruning caused a decrease in yield/meter trellis and Ravaz index. In 2009, repeated measures analysis showed significant effects of severe pruning increasing brix, pH and sugar to acid ratio while shoot thinning and both sides leaf removal had no significant effects on maturation rate of performance indicators. At harvest 2009, severe pruning increased brix, pH, tannin, anthocyanins, phenolics, color density, potassium, amino acid % of yeast assimilable nitrogen (YAN), and the following ratios: sugar/acid, amino acid/ammonium, tannin/anthocyanins and malic/tartaric acid. Additionally, severe pruning decreased tartaric acid, yield/meter trellis, ammonium % of YAN and Ravaz index. The findings presented in this thesis suggest that severe pruning could be used as a tool in viticultural areas with short growing seasons because of the increased ripening speed observed. However, because severe pruning generally increases berry size which is negative for vinification, it should be studied further with irrigation and management practices that decrease berry size.

‘MidSouth’, a relatively low maintenance interspecific hybrid bunch grape currently grown in South Mississippi, has low sugar and high acid levels for red wine use. Two studies, conducted at the Mississippi State University McNeill Research Unit in 2020 and 2021, determined the effects of pruning timing, leaf removal, and shoot thinning on ‘MidSouth’ development and fruit and wine quality. Treatments in the first study included early versus normal pruning timing, both with and without leaf removal, and treatments in the second study included leaf removal, shoot thinning, and control vines. Cluster temperatures, leaf chlorophyll, berries per cluster, berry and cluster weights, crop yield, Ravaz index, total soluble solids, titratable acidity, juice pH, monomeric anthocyanin pigment, and total phenolic content data were collected. It was determined that ‘MidSouth’ fruit quality can be altered through canopy manipulation, but not enough of a desired effect was achieved for these practices to be recommended.

Sanding and pruning are two practices used in the cranberry industry for vine management and yield stimulation. This study compared the effects of varying levels of sanding and pruning in April 2006 on vine canopy characteristics and yield over the course of two growing seasons. Each practice was applied at four levels: sanding at four depths: control (0 cm), light (1.5 cm), moderate (3.0 cm), or heavy (4.5 cm) of sand; pruning at four numbers of passes with a commercial pruner: control (0 passes), light (1 pass), moderate (2 passes), and heavy (3 passes). Pruning levels had no affect on upright density over the two seasons whereas heavy sanding treatment decreased the number of uprights per unit area significantly. A linear increase in light penetration was observed for the first season only as intensities increased for both pruning and sanding. Number of fruiting uprights relative to total uprights decreased in the first year as intensity increased for sanding and pruning. This effect continued in the second year for sanding treatments. Yield and net returns averaged over the two years were greatest in lightly pruned plots, followed by lightly sanded plots. Moderate and heavy treatments were associated with lower yields and net returns than those for the controls.

Quantification of grape glycosides has been suggested as an objective index of grape quality. Two studies were undertaken to observe the influence of vineyard management on grape glycosides. In the first study, three crop levels from mature Cabernet Sauvignon (<i>Vitis vinifera</i> L.) vines grown in eastern Virginia were evaluated for their influence on grape glycosides, expressed as red-free glycosyl glucose (GG). Crop levels averaged 3.2, 5.1, and 6.4 kg/vine resulting in leaf area to fruit weight ratios (cm²/g) of 34.4, 27.0 and 19.2, respectively. Red-free GG was greatest in juice from fruit of the low treatment at four of seven sampling dates, including harvest. Phenolic glycosides were found to comprise as much as half of the total GG value. In a second study, shoot thinning, mechanical and hand fruit zone leaf removal of mature Cabernet Sauvignon grapevines were evaluated for their influence on red-free GG. Two shoot densities were examined, each with no leaf removal (No LR), mechanical leaf removal (M LR) or mechanical plus hand leaf removal (M+H LR) imposed five weeks post-bloom. Red-free GG was increased by leaf removal of shoot thinned vines and was greatest with mechanical plus hand leaf removal. / Master of Science

Current fruit-zone management recommendation in the eastern US aims for 1-2 basal shoot leaf layers after fruit set to limit fungal disease and sunburn incidence, and prevent extreme heating of grapes. The goal of this work was to assess if fruit-zone leaf removal to an uncommonly greater extent, and/or at an earlier phenological stage, would favorably alter yield components or fruit composition in three popularly grown, red-fruited, Bordeaux varieties – Cabernet franc, Petit Verdot, and Cabernet Sauvignon. Pre-bloom leaf removal to various extents reduced crop yield by 41-78% when compared to no leaf removal across seasons and varieties. Pre-bloom leaf removal implementation in consecutive seasons tended to further reduce crop yield components compared to implementation in the first year. Pre-bloom leaf removal tended to reduce cluster compactness and bunch rot incidence when compared to post-fruit set and no leaf removal. Basal leaf removal to the greatest extents inconsistently reduced soluble solids and titratable acidity across varieties and seasons. Pre-bloom and post-fruit set leaf removal to the greatest extent consistently increased total grape phenolics and anthocyanins compared to no leaf removal in Cabernet Sauvignon, but inconsistently increased total grape phenolics compared to no leaf removal in Cabernet franc and Petit Verdot. Basal leaf removal to the greatest extents tended to increase the synthesis and degradation of carotenoids more consistently than no leaf removal, and this was particularly true for zeaxanthin. Petit Verdot and Cabernet franc wine color and aroma were inconsistently distinguishable between leaf removal treatments, and color intensity was rated higher in wines made with fruit from pre-bloom leaf removal compared to modest post fruit-set leaf removal plots. Waiting until after fruit set to remove fruit-zone leaves maintained crop yield and offered comparable improvements in fruit composition to pre-bloom leaf removal. Pre-bloom leaf removal of no more than four leaves is recommended to limit crop yield reduction, and modestly improve fruit composition. This work showed that fruit-zone leaf removal does not need to be conservative in the eastern US, particularly because the climate does not appear to be detrimental to fruit composition, and open fruit-zones reduce grape fungal disease incidence. / Ph. D.

Thesis (MScAgric)--Stellenbosch University, 2014 / ENGLISH ABSTRACT: The objective of the study was to determine combined effects of irrigation and canopy management practices on grapevine water status, growth, yield and juice characteristics. The field study was carried out with Shiraz/110R grapevines in the Breede River Valley. Grapevines were drip irrigated at 30%, 60% and 90% plant available water (PAW) depletion, respectively. For each PAW level, grapevines had (i) suckered, vertical shoot positioned (VSP), (ii) non-suckered, VSP and (iii) sprawling canopies. Treatments were replicated three times in a randomised block design and applied during the 2011/12 and 2012/13 seasons. Irrigation applied at low PAW depletion levels, i.e. high frequency irrigation, required substantially higher irrigation volumes compared to high depletion levels, i.e. low frequency irrigation. Low frequency irrigation increased grapevine water constraints compared to high frequency irrigation. Sprawling canopy grapevines experienced more water constraints than VSP grapevines. Grapevines irrigated at 90% PAW depletion experienced strong water constraints. Low frequency irrigation seemed to accelerate berry ripening compared to high frequencies, probably due to smaller berries and lower yields. Sprawling canopies consistently enhanced berry ripening due to more sunlight interception by the leaves. Berry ripening of VSP grapevines was slower, but inconsistent between seasons. Level of PAW depletion and canopy management practice did not affect number of leaves per primary shoot. Low frequency irrigation reduced number of leaves per secondary shoot. Leaf number per shoot contributed more to total leaf area than leaf size. Level of PAW depletion did not affect number of shoots per grapevine. Suckering reduced number of shoots per grapevine. Low frequency irrigation reduced total leaf area per grapevine compared to high frequency irrigation. Effects of canopy management practice were more pronounced in the case of high frequency irrigation compared to low frequency irrigation. At pruning, primary cane length was not affected by level of PAW depletion or canopy management practice. Secondary cane mass and diameter were not affected by canopy management practice. Multiple linear regression showed that cane mass was a function of cane length and diameter. Low frequency irrigation reduced berry mass compared to high frequency irrigation, irrespective of canopy management practice. However, at harvest there was no difference in berry mass between 30% and 60% PAW depletion. Low irrigation The objective of the study was to determine combined effects of irrigation and canopy management practices on grapevine water status, growth, yield and juice characteristics. The field study was carried out with Shiraz/110R grapevines in the Breede River Valley. Grapevines were drip irrigated at 30%, 60% and 90% plant available water (PAW) depletion, respectively. For each PAW level, grapevines had (i) suckered, vertical shoot positioned (VSP), (ii) non-suckered, VSP and (iii) sprawling canopies. Treatments were replicated three times in a randomised block design and applied during the 2011/12 and 2012/13 seasons. Irrigation applied at low PAW depletion levels, i.e. high frequency irrigation, required substantially higher irrigation volumes compared to high depletion levels, i.e. low frequency irrigation. Low frequency irrigation increased grapevine water constraints compared to high frequency irrigation. Sprawling canopy grapevines experienced more water constraints than VSP grapevines. Grapevines irrigated at 90% PAW depletion experienced strong water constraints. Low frequency irrigation seemed to accelerate berry ripening compared to high frequencies, probably due to smaller berries and lower yields. Sprawling canopies consistently enhanced berry ripening due to more sunlight interception by the leaves. Berry ripening of VSP grapevines was slower, but inconsistent between seasons. Level of PAW depletion and canopy management practice did not affect number of leaves per primary shoot. Low frequency irrigation reduced number of leaves per secondary shoot. Leaf number per shoot contributed more to total leaf area than leaf size. Level of PAW depletion did not affect number of shoots per grapevine. Suckering reduced number of shoots per grapevine. Low frequency irrigation reduced total leaf area per grapevine compared to high frequency irrigation. Effects of canopy management practice were more pronounced in the case of high frequency irrigation compared to low frequency irrigation. At pruning, primary cane length was not affected by level of PAW depletion or canopy management practice. Secondary cane mass and diameter were not affected by canopy management practice. Multiple linear regression showed that cane mass was a function of cane length and diameter. Low frequency irrigation reduced berry mass compared to high frequency irrigation, irrespective of canopy management practice. However, at harvest there was no difference in berry mass between 30% and 60% PAW depletion. Low irrigation. / AFRIKAANSE OPSOMMING: Die doelwit van hierdie studie was om die gekombineerde effek van besproeiing en lowerbestuurspraktyke op wingerd waterstatus, groei, opbrengs en druiwesap eienskappe te bepaal. Die veld studie is uitgevoer met Shiraz/110R wingerdstokke in die Breede Rivier Vallei. Wingerdstokke was d.m.v. drupbesproeiing teen 30%, 60% en 90% plant beskikbare water (PBW) ontrekking, onderskeidelik besproei. Vir elke PBW ontrekkingspeil, was wingerdstokke (i) gesuier en vertikale lootposisionering toegepas, (ii) ongesuier en vertikale lootposisionering toegepas en (iii) geen lowerbestuur toegepas nie (lowers wat oophang). Behandelings is drie keer in ‘n ewekansige blokontwerp herhaal en tydens die 2011/12 en 2012/13 seisoene toegepas. Besproeiing wat teen ‘n lae PBW ontrekkingspeil toegedien is, d.w.s. hoë frekwensie besproeiing, vereis aansienlik hoër besproeiings volumes i.v.m. hoë besproeiing ontrekkingspeile, d.w.s. lae frekwensie besproeiing. Wingerdstokke wat oopgehang het meer watertekorte as vertikaal lootgeposisioneerde wingerdstokke ervaar. Wingerdstokke wat teen 90% PBW ontrekking besproei was, het sterk watertekorte ervaar. Dit het voorgekom of lae frekwensie besproeiing korrelrypwording versnel het i.v.m. hoë frekwensie besproeiing. Dit was heelwaarskynlik a.g.v. kleiner korrels en laer opbrengste. Wingerdstokke wat oophang het, het konsekwent korrelrypwording versnel a.g.v. meer sonligonderskepping deur die blare. Korrelrypwording van vertikaal lootgeposisioneerde wingerdstokke was stadiger, maar teenstrydig tussen die seisoene. Plant beskikbare water ontrekkingspeil en lowerbestuurspraktyke het geen invoeld gehad op die aantal blare per primêre loot nie. Lae frekwensie besproeiing het die aantal blare per sekondêre loot verminder. Die hoeveelheid blare per loot het ‘n groter bygedra gemaak i.v.m. blaar grootte. Plant beskikbare water ontrekkingspeil het geen invloed gehad op die aantal lote per wingerdstok nie. Suier verminder die aantal lote per wingerdstok. Lae frekwensie besproeiing verminder die totale blaar oppervlak i.v.m. hoë frekwensie besproeiing. Die effek van lowerebestuurspraktyke is duideliker sigbaar by hoë frekwensie besproeiing i.v.m. lae frekwensie besproeiing. Primêre lootlengte was nie deur PBW ontrekkingspeil of lowerbestuurspraktyke beïnvloed nie. Sekondêre lootmassa en -deursnit is nie deur lowerbestuurspraktyk beïnvloed nie. Meervoudige lineêre regressie het getoon dat lootmassa ‘n funksie van lootlengte en -deursnit was. Lae frekwensie besproeiing het korrelmassa verminder ongeag die lowerbestuurspraktyk i.v.m. hoë frekwensie besproeiing. Daar was egter geen verskil in korrelmassa by oes tussen 30% en 60% PBW ontrekking nie. Lae frekwensie besproeiing was geneig om suiker akkumulasie te versnel i.v.m. hoë frekwensie besproeiing. Wingerdstokke wat oopgehang het, het veral by lae frekwensie besproeiing korrelrypwording versnel i.v.m. vertikaal lootgeposisioneeide wingerdstokke. Suikerinhoud per korrel het geneig om toe te neem totdat dit ‘n plato bereik het. Hierdie plato was meer prominent by hoë frekwensie besproeiing i.v.m. lae frekwensie besproeiing. Wingerdstokke wat oopgehang het, het ook hierdie plato vroeër bereik i.v.m. vertikaal lootgeposisioneerde wingerdstokke. By oes was die totale titreerbare suur (TTS) hoër vir wingerdstokke wat vroeër geoes was. As gevolg van versnelde rypwording was TTS van wingerdstokke wat teen lae frekwensie besproei is hoër i.v.m. hoë frekwensie besproeiing. ‘n Ligter oeslading in verhouding tot ‘n hoër blaaroppervlak het ook gelei tot hoër TTS by oes. Plant beskikbare water ontrekkingspeil en lowerbestuurspraktyke het geen invloed op die pH gehad met oes nie. Die hoeveelheid trosse per wingerdstok het nie duidelike tendense gewys wat verbind kon word met watertekorte wat deur die stokke ervaar is nie. Gesuierde vertikaal lootgeposisioneerde wingerdstokke het die hoeveelheid trosse per stok verminder i.v.m. die ongesuierde vertikaal lootgeposisioneerde wingerdstokke en wingerstokke wat oopgehang het. Trosmassa het dieselfde tendense as korrels per tros gevolg. Lae frekwensie besproeiing het opbrengs aansienlik verminder i.v.m. hoë frekwensie besproeiing. Gesuierde vertikaal lootgeposisioneerde wingerdstokke het geneig om opbrengste te verminder i.v.m. ongesuierde vertikaal lootgeposisioneerde wingerdstokke. Hierdie effek het egter verdwyn waar wingerdstokke teen 90% PBW ontrekking besproei was. Druif skade a.g.v. suurvrot was meer prominent by hoë frekwensie besproeiing, veral vir ongesuierde vertikaal lootgeposisioneerde wingerdstokke. Total opbrengs verlies, uitgedruk as ‘n persentasie, was hoofsaaklik ‘n funksie van sonbrand eerder as ‘n funksie van suurvrot.

Cashmere Forest is currently a production forest comprised of mostly radiata pine (c.85%), Douglas fir (c.5%) and some non plantation areas. The Port Hills Park Trust Board (PHPTB) is interested in purchasing Cashmere Forest for the purpose of creating a public forest park environment where forestry, indigenous biodiversity, recreation and the environment are goals of sustainable management. For this purpose this draft forest management (DFM) plan has been prepared. The preparation of the Cashmere DFM plan comprised three main components: 1. An economic analysis of the current plantation component of Cashmere Forest. 2. Preparation of a draft forest management plan which encompasses the management of plantation and non plantation areas. 3. Preparation of a geographic information system (GIS) for Cashmere Forest. Economic analysis evaluated clearfell, coupe (2 to 5 ha), and a mixture of coupe and continuous canopy management (CCM) as harvesting scenarios. The coupe CCM mix was recommended for implementation primarily as it best suited long term management goals for Cashmere Forest Park while also returning modest value (NPV $561, 966). Normal cashflow analysis was also used to analyse cashflow over the first thirty years of operation from 2007. Under coupe/CCM, accrued profit does not become permanently positive until around 2019 due to initial infrastructure costs. Accrued revenue culminates at around 4 million after 30 years. This figure may drop following implementation of high pruning, alternative growth models and indigenous restoration. The Cashmere DFM plan begins with the 200 year vision which sees a Forest Park ecosystem that achieves production, environmental, ecological and recreational goals appropriate to its Port Hills location. Production forestry is practiced through the selective harvesting of a range of naturally regenerated exotic and restored indigenous species. Landscape, soil and water resources are sustainably managed through the retention of a mixed forest canopy. The forest park has been significantly augmented with indigenous flora and fauna typical of the Port Hills and ecologically significant areas are managed specifically for their indigenous biodiversity. Park recreational users are enjoying ongoing utilisation of a unique Canterbury landscape. Plantation forest management involves coupes of between 2 to 5 ha which will be harvested with cable or ground based systems with areas split approximately 50:50 between the two. Cable harvesting will be carried out with a swing yarder system with ground based operations carried out with track skidders. CCM will be carried out on a trial basis in three compartments. Re-establishment of plantation areas will aim towards occupying around 58% of Cashmere Forest, comprised of areas of radiate pine 65%, radiata pine/eucalypt 24%, Douglas fir/eucalypt 5% and Alternative species 6%. Non plantation areas are identified as either bluff, track or clearing. Within each area there may be one or more vegetation type including tussock grassland, mixed shrubland, rock association and any mixture of the three. It is proposed that the non plantation area will eventually increase to include riparian buffers 31%, restored native 55%, bluff 10% and track 4% areas, reflecting the long term vision of increased native areas in Cashmere Forest. Monitoring of forest operations, restoration, recreation and management progress will be integral to the successful implementation of the Cashmere DFM plan. A database of information will be created to allow periodical reviews of processes and predictions and reconciliation of costs and revenues associated with the management of Cashmere Forest. Periodical reviews will also be undertaken by an independent management advisory group who can liaise with the project manager of Cashmere Forest Park to discuss issues and aid planning and ensure the successful establishment of this unique park resource.