Dissertations / Theses on the topic 'Caterpillars and tree damage'

Glaze damage to canopy trees, gap size and seedling regeneration was surveyed relating to site topographic features after a major glaze storm at Fishburn Forest in the central Appalachian mountain region. The survey sites were stratified according to aspect and landform, and sample plots were randomly assigned to each topographic category. The canopy trees in the plots were tallied and their damage was visually classified. The results demonstrated that different species had different susceptibilities to glaze damage and susceptibility of species varied as topography changed. Virginia pine was the most susceptible species. In general, trees had the greatest damage on steep slopes and eastern aspects, and least damage on toe-slopes. Some species varied greatly in their susceptibility to glaze damage across the topographic categories, such as red maple, while some species varied little, like blackgum. Basal area was reduced 6% and varied due to species and topography. Where glaze damage was severe, gaps in the forest canopy were created. Gap sizes and the effects of gap size and topography on seedling regeneration within gaps caused by glaze damage were assessed. Seedlings were tallied by species and height in microplots within each sample plot and in the nearest gap, where gap size was measured. Gap size varied from 14,000 m2 to less than 20 m2. Average gap size was 255 m2. Canopy tree damage, forest type and topography were the most important factors affecting gap size. Gaps tended to be larger on steep backslopes. Common seedling species in both gaps and understory were sassafras, serviceberry and red maple. Disturbance affected both seedling height and density, as did topography. However gap size had effect only on seedling height. The future forest in this area is unlikely to change significantly, as species composition of seedlings was largely unaffected by the glaze storm damage.
Master of Science

Experiments were conducted to determine the effects of applying fill soil around existing trees and mechanisms for species tolerance to soil compaction, both common site disturbances in urban forestry. Groups of 22-year-old white oak (Quercus alba) and 13-year-old sweetgum (Liquidambar styraciflua) were subjected to one of three treatments: a control, fill (20 cm of subsoil spread over the root zones), and compacted fill (same as fill soil, but compacted). Additionally, individual trees had tree wells (fill soil pulled away from trunks), or not. After three years, treatments had no consistent effect on tree growth, chlorophyll fluorescence, or soil respiration. However, soil treatments disrupted normal soil moisture patterns at both sites. Roots of white oak grew into fill layers, although overall root growth was not significantly affected by treatment. Sweetgum roots grew very little into fill soils. However, root distribution shifted upward in the original soil under uncompacted fill. Other factors associated with raising the soil grade, such as soil trafficking and root severance, may be largely responsible for the tree decline often attributed to construction fill. Another experiment investigated the relationship between tolerance of wet soils and the ability to grow in compacted soils. It was hypothesized that tree species tolerant of wet soils would have opportunities for root growth in compacted soil when high soil moisture reduced soil strength. Seedlings of flowering dogwood (Cornus florida), a species intolerant of inundation, and silver maple (Acer saccharinum), a bottomland species, were grown in a loam soil maintained at various combinations of soil strength and soil matric potential. In moderately compacted soil (1.5 g cm-3 bulk density), maple seedlings, but not dogwoods, had greater root growth rate, root length per plant, and ratio of root length to root dry weight in the wet soil (0.006 MPa soil matric potential) than in the moist and dry soils (0.026 and 0.06 MPa, respectively). No such effect was detected in highly compacted soil (1.7 g cm-3). It can be concluded that silver maple roots can grow in moderately compacted soil when high soil water content decreases soil strength, whereas dogwood is unable to take advantage of this opportunity.
Ph. D.

A survey of dipterocarp forest in four sites revealed that the incidence of stem canker was relatively low but high localized incidences were recorded. No consistent association was obtained between the presence of mechanical damage and cankers. Cankers occurred more frequently on dipterocarps and less frequently on euphorbs. Field studies and experimental manipulations were used to compare sapling resistance and responsiveness to wounding and stem breakage in relatively nutrient-rich, alluvial forest and relatively nutrient-poor, sandstone ridge forest. Species found on sandstone ridges showed greater resistance to damage (e.g., greater stem flexibility, narrower crowns) than those on alluvial soils. Species common on alluvial soils tended to be more responsive to damage (e.g., faster wound closure rates, more likely to re-sprout). Results from manipulation experiments conducted on pot-grown seedlings were consistent with results from the field studies, where conditions of greater nutrient availability, saplings closed wounds at faster rates, had less flexible stems, more narrow crowns, and lower levels of foliar total phenolics. Species showed differential rezones to resource availability which, in part, may relate to contrasting strategies for investment in passive defence (i.e., resins and phenolics) over investment in growth. Through their narrower crowns, greater whole stem flexibility, and lesser stem taper, tree species characteristic of sandstone ridges had greater resistance to mechanical damage from debris falling from above than congeneric species characteristic of alluvial soils. Tree species characteristic of alluvial soils were more responsive to damage than congeners on sandstone ridges, by producing earlier and longer sprouts following stem snapping and more rapid rates of wound closure following wounding.

The basis for the selection of trees to be used in the production of dendrochronologies has long been an issue (Douglass 1946; Fritts 1976). In humid regions the common practice has been to use trees that appear to be in good health. As a part of a larger study involving the impact of ice storms on tree-ring increments (Travis 1989), we show that trees stressed as a result of ice damage produced a stronger climatic signal than nondamaged trees.

A major challenge in agroecosystems is how to manage the systems so that it reduces crop pests and enhances natural pest control. This thesis investigates patterns of crop pests and top-down effects of birds and arthropod predators in relation to land-use composition across spatial scales. In paper (I) I examined the crop distribution and land-use types in relation to the crop raiding patterns in 15 transectsin sites close to and far from forests along with a questionnaire survey at household level. I found severe crop raiding close to forests, but it had no impact on crop composition growing between the two sites. In paper (II) I examined the effect of forest and tree cover, at local and landscape scales, on the abundance of arthropod predators by collecting specimens from 40 home gardens. My result showed higher abundance of arthropod predators when either the home garden or the surroundings had a high tree-cover, compared to when tree-cover at both scales was similarly either high or low. In paper (III) I investigated the effect of excluding birds and arthropod predators on leaf damage on rape seed in 26 home gardens. I found stronger top-down impacts from arthropod predators on crop pests in tree-poor gardens than in tree-rich gardens. There was no effect of birds. In paper (IV) I explored the effect of landscape complexity on bird and arthropod predation using plasticine caterpillars in 36 home gardens across landscapes. The rate of arthropod predation on caterpillars was higher in simple than in complex landscapes. The rate of bird predation did not vary between complex and simple landscapes. In simple landscapes, arthropod predation was higher than that of birds. The overall results suggest that simplified gardens/landscapes still have enough habitat heterogeneity to support arthropod predators for the significant top-down controlling effect on crop pests. However, I did not find clear effect of complexityon the top-down effect of birds.

At the time of the doctoral defence the following papers were unpublished and had a status as follows: Paper 1: Manuscript; Paper 3: Manuscript; Paper 4: Manuscript

High-wind generating extratropical cyclones routinely strike southwest British Columbia. Improved understanding of these storms could help mitigate damage to electrical and other infrastructure. All independent windstorms from 1964-2012 were determined using the Victoria, Vancouver and Abbotsford hourly surface observations. For all qualifying events 1994-2012, storm tracks and central pressure tendencies were determined using surface maps. Storms were classified by peak wind direction and track location. Detailed synoptic and mesoscale maps were made and analyzed for eight strong windstorms. BC Hydro Corporation distribution-system power outage data from October 2005 to August 2009 was used in an analysis of tree-related line faults within a 50 km radius of Vancouver. For events with peak speed >40 km h-¹, maximum wind, gust, wind direction, storm total precipitation and storm duration were used to predict line faults using linear and Poisson regression. Data from four strong windstorms was used in an hour-by-hour analysis of wind speed and line faults. There were two dominant categories of cyclonic windstorm in this region: westerly and southeasterly. Cyclone tracks had much variation. However, compared to westerly storms, southeasters tended to have a stronger northward component to their direction of motion and tended to pass closer to the study region. Most low-pressure centers weakened rapidly as they moved inland and, as a result, peak winds typically occurred at landfall. The exception is for westerly storms where the wind is dependent on an onshore pressure gradient behind the low. There was moderately strong linear relationship between peak two-min wind or five-s gust and the frequency of distribution line faults. Poisson regression models indicate the potential for widespread grid damage for wind speeds approaching the historic 12 Oct 1962 windstorm. On average, southeasters cause approximately 1.5-1.9 times more line faults than westerly windstorms. A few-hour lag in the occurrence of line faults relative to observed wind speed, perhaps due to reporting delays, was observed. This has not been reported before and could confound analyses that use daily data. The modeling done here could be expanded to forecast storm impacts to the power grid using numerical weather prediction model inputs.
Forestry, Faculty of
Graduate

Annual rings of Douglas-fir, Pseudotsuga menziesii (Mirb.) Franco, which sustained 1 year of defoliation by the western false hemlock looper, Nepytia freemanii Munroe (Lepidoptera: Geometridae), showed a period of decrease in breast height ring width starting in the year that followed the damage. The magnitude of the decrease was related to the degree of defoliation: there was no ring width decrease on trees that were 0-10% defoliated; the decrease became progressively more noticeable in trees which sustained increasingly higher defoliation; and it was maximum in trees which sustained 91-100% defoliation. This period of reduction lasted 1 to 5 years and was followed by a period of above-normal growth which was related to defoliation in a similar manner: it was absent in trees 0-10% defoliated and maximum in the 91-100% tree defoliation class. Increase in defoliation caused a significant increase in index standard deviation, autocorrelation and mean sensitivity.

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Dissertacao (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

Increasing productivity, reducing cost, reducing soil damage, reducing the impact of harvesting on standing tree and regeneration are all very important objectives in ground skidding system in the management of the Hyrcanian forest. The research carried out to obtain these objectives included four logging methods, tree length method (TLM), long length method (LLM), short length method (SLM), and wood extraction by mule (mule) in northern Iran. In order to determine the cost per unit, time study techniques were used for each harvesting method, time study data are shifted to logarithmic data based on 10. On the basis of the developed models simulated, 11 skidding turns are simulated and the unit cost are estimated depending on the diameter of the log (DL), skidding distance (SD), and the winching distance (WD) for 11 different cycles with TLM, LLM and SLM. The results showed that on average, the net costs per extraction of one cubic meter of wood were 3.06, 5.69, 6.81 and 34.36 €/m3 in TLM, LLM, SLM and mule. The costs depending on diameter of log (DL), skidding distance (SD) and winching distance (WD) showed that the most economical alternative for Northern Iran is TLM. In the cut-to-length system, the costs of both alternatives LLM, SLM were significantly dependent on DL. , thus the result of this study suggests that as long as the diameter of the felled trees is less than 40 cm, the cut-to-length system is not an economical alternative, whilst the cut-to-length method can be applied for trees with a diameter more than 40 cm. Where diameters are more than 40 cm TLM it is more economical than SLM, however it was not significantly different. Depending on SD in short skidding distance SLM is preferable to LLM but in cases of long skidding distance LLM is more economical than SLM. The winching distance affect was not a factor on cost. To assess the damage on seedlings and standing trees a 100% inventory method was employed in pre-hauling and post-hauling, alongside of skidding trails, winching strips and mule hauling with a 12m width. To chose the best alternative depending on standing damage the Analysis of multiple criterial approval (MA) was applied. The amount of trees damaged by winching operation were 11.89% in TLM, 14.44% in LLM 27.59%, SLM and 0 stem and by skidding operation were 16.73%, 3.13% and 8.78% of total trees in TLM, LLM and SLM. In the winching area about 14%, 20%, 21% and 6 % of the total regeneration was damaged by TLM, LLM, SLM and mule and the skidding operation damaged 7.5% in TLM, 7.4 % LLM and 9.4% in SLM. The friendliest alternative to residual standing was mule but in manual method (where the wood extraction is done by skidder) MA showed that the best alternative depending on residual damage is LLM. To determine the degree of soil compaction a core sampling technique of bulk density was used. Soil samples collected from the horizontal face of a soil pit at 10 cm depth soil core, at 50m intervals on skid trials, in winching strips and control are (no vehicles pass) a soil sample was taken at 10m intervals in the hauling direction of the mule. In order to determine the post-harvesting extent of disturbance on skidding trails by skidding operations, the disturbed widths were measured at 50 m intervals along the skid trails. In the winching area, where the winched logs created a streak of displaced soil, the width of the displaced streak was measured at 5 m interval along the winching strip. In mule hauling operations the width of a streak created by a mule foot track was measured at 10 m intervals. To compare increased average bulk density between alternatives one way The ANOVA, Duncan test and Dunnett t-test with a 95 % confidence level were used. A General linear model was applied to relate the increasing bulk density and the slope gradient. To realize the correlation between the increment of soil bulk density and the slope gradient and the correlation between the soil compaction and soil moisture content (%) The Pearson correlation test was applied. To choose the best alternative (in manual method) a MA test was applied again. The bulk density on the skidding trail increased 51 % for 30 skidding turn, 35 % for 31 skidding turn (one unloaded and one loaded pass) and 46% for 41 skidding turn. Results of ANOVA (p < 0.05) show significant differences of bulk density between alternatives. Duncan test and the Dunnett t-test indicated that the increasing soil bulk density was not significant between control samples and winching strip of TLM and extraction by mule samples. The general linear modeling and Pearson correlation test results indicated that the slope gradient had an insignificant effect on soil compaction, whilst the Pearson test indicates a medium negative correlation between soil compaction and percentage of soil moisture. By ground-based winching operation 0.07%, 0.03%, 0.05% and 0.002% of the total area and by ground based skidding operation 1.21%, 1.67%, 0.81% and 0.00% of total area was disturbed and compacted in TLM, LLM, SLM and mule. The Pearson correlation results show that the width of disturbed area was significantly influenced by the diameter of logs and length of logs (p ˂ 0.05), but there is no significant correlation between soil disturbance width and slope. The results of analysis of MA showed that soil compaction was not related to logging method but sensitivity analysis of MA shows that LLM and TLM are both preferable to SLM.

An estimated 39 million m³ of timber was damaged across the Southeast Forest District of Mississippi due to Hurricane Katrina. Aggregated forest plot-level biometrics was coupled with wind, topographical, and soil attributes using a GIS. Data mining through Regression Tree Analysis (RTA) was used to determine factors contributing to shear damage of pines and wind-throw damage of hardwoods. Results depict Loreys Mean Height (LMH) and Quadratic Mean Diameter (QMD) are important variables in determining the percentage of trees and basal area damaged for both forest classes with sustained wind speed important for wind-throw and peak wind gusts for shear. Logistic regression based on stand damage classification compared to RTA revealed LMH, stand height to diameter ratio, and sustained wind variable concurrence. Reclassification of MIFI plot damage calls based on percentage of trees damaged increased predictability of wind-throw and shear classification. This research can potentially aid emergency and forest managers for better mitigation and recovery decisions following a hurricane.

An increment borer is the primary tool used to collect samples for dendrochronological analyses. These are precision instruments and users should be trained in their proper use, care, and maintenance. In this paper, I describe the various parts of an increment borer and how to keep these in working condition. I provide details on how to sharpen an increment borer, properly core a tree, check for core compression ("jamming"), extract the core, and store the core for transport. I provide tips on how to clear a jammed borer and remove a borer stuck in a tree. An important topic concerns the effects of boring on trees. The majority of studies indicate that conifers are minimally affected by both fungal decay and discoloration, whereas certain hardwood species can sustain major internal damage. Plugging the holes created by coring is unnecessary.

Bendrą šalies miškų sanitarinę būklę ženkliai veikia paprastosios pušies ir paprastosios eglės formuojamų grynų arba mišrių medynų sveikatingumas, kadangi šios dvi spygliuočių rūšys užima daugiau nei pusę (56,1 %) šalies medynų ploto. Nors per paskutinį dešimtmetį pušynų plotas padidėjo 9,7 tūkst. ha, tačiau šalies eglynų plotas per tą patį laikotarpį sumažėjo 16,2 tūkst. ha. Kaip viena iš galimų paprastosios eglės formuojamų medynų mažėjimą sukeliančių priežasčių gali būti įvardytas gamtinių veiksnių sukeliamų pažeidimų eglynuose skaičiaus didėjimas. Šių veiksnių įtaka Lietuvos spygliuočių būklei bei kaitos tendencijos įgyja nemažai svarbos besikeičiančio klimato sąlygomis. Šio baigiamojo magistro darbo tikslas – pagal miškų monitoringo duomenis nustatyti biotinių ir abiotinių medžių pažeidimų kaitos pokyčių tendencijas šalies eglynuose ir pušynuose bei įvertinti galimą klimato kaitos įtaką spygliuočių pažeidžiamumui. Pagal miškų monitoringo duomenis nustatytas gamtinių veiksnių pažeidimų skaičius paprastosios eglės ir paprastosios pušies formuojamuose medynuose leido įvertinti šių medžių rūšių pažeidžiamumo kaitą 1989-2013 metų laikotarpiu. Pažeidimų gausos kitimo vertinimui naudota koreliacinė analizė, o vizualiai identifikuojamų pažeidimų poveikis medžio būklei įvertintas paskaičiavus skirtumus tarp pažeidimo požymius turinčių ir jų neturinčių medžių vidutinės lajos defoliacijos. Taip pat analizuotas ir medžių pažeidimų pasiskirstymas pagal tam tikras klimato sąlygas... [toliau žr. visą tekstą]
The condition of coniferous tree species is the main cause of all country forest health because of high proportion of coniferous stands in a country forests. These species cover more than half (56,1 %) of forest land. The area of Scots pine stands expanded by 9700 ha over the last ten years while the area of Norway spruce reduced by 16200 ha during the same period. Damages of biotic and abiotic factors may be called as the one of main cause of this reduction in spruce stands. Moreover the influence of the state of coniferous tree species by these factors increases under the climate change. The aim of this Master thesis is to establish the extent of biotic and abiotic damages and its changes in coniferous stands in Lithuania according to the forest monitoring data and to evaluate the possible influence of climate change to vulnerability of these tree species. According to forest monitoring data the number of biotic and abiotic damages in Norway spruce and Scots pine stands helped to evaluate the tendency of vulnerability of these tree species during the 1989-2013. Moreover, the correlation analysis revealed the changes in the extent of trees’ damages and the influence of visually identifiable damages on the condition of tree has been determined by subtracting the average overgrowth’s defoliation of undamaged trees from damaged trees. Also the distribution of tree damages in different climatic regions in a country was analysed to evaluate the impact of climate change in... [to full text]

Fuels management in eucalyptus plantations is essential to minimise the impact of wildfire. Prescribed burning has the potential to reduce the fuel hazard in plantations, but is not routinely conducted due to concerns relating to tree damage. Through a series of experimental burns, the issues of tree damage are addressed and minimum tree sizes are recommended that are capable of withstanding the effects of low to moderate intensity fires. Data was collected between 2005 and 2007 over six sites, two species, and three age classes. Tree response results came from multiple measurements of over 1700 individual trees. The fuel characteristics commonly found in sub-tropical eucalypt plantations from age four to eleven are described and quantified. These fuel characteristics are related to fire behaviour and new fire behaviour models, specific to young eucalypt plantations, are presented. The fuel characteristics that most influence fire behaviour in young eucalypt plantations are fuel load, fuel height, and fuel moisture content. These characteristics can be used to predict the rate of spread of a plantation fire under benign wind conditions. A novel technique for assessing the extent of stem damage in eucalypts is developed and described. This technique enables immediate assessment of stem damage following fire; previous assessment techniques recommend waiting a considerable period of time (up to 2 years) until dead bark dropped off and fire scars were evident. This new assessment technique is likely to be suitable for post-fire assessment of any eucalypt species and will provide forest managers with the capability of deciding whether to leave a stand to ???grow-on??? or commence recovery operations. Minimum stem sizes recommended to ensure no long-term damage are between 5 ??? 8 cm DBH (diameter at breast height, i.e. 1.3m above ground level) for Eucalyptus dunnii (Dunn???s white gum) and 5 ??? 13 cm DBH for Corymbia spp. (spotted gum) depending on the quantity of fuel around the stem. Stem sizes vary between species because of the variation in bark thickness between species. This thesis provides all the necessary information to conduct prescribed burning operations in young eucalypt plantations.

The aim of this thesis is to determine the amount of indemnity for total damage caused by a falling tree during the gale on a cottage in Roudné near Nové Hrady. The theoretical part deals with basic insurance terminology and basic terminology and methods used in property evaluation. The practical part describes the original condition of the property and its evaluation before the insured event using a cost method and complying with the evaluation regulation. Furthermore, this thesis deals with determination of the costs through the itemized budget for bringing the property to its original state. The conclusion deals with the impact of reconstruction on the extent of indemnity.

Etude du role des termites dans 3 sites: une foret secondaire et 2 plantations. Les populations de termites sont plus importantes en foret. Le defrichement provoque une chute des effectifs qui se reconstituent ensuite rapidement. En saison seche, les termites s'enfoncent dans le sol. La recolte de bois mort par les termites varie selon la saison. Les termites sont inoffensifs pour les arbres eb bon etat. Par contre, l'action des termites constitue un reel danger pour les jeunes arbres, surtout chez les sujets fletris. Il existe une correlation positive entre le degre de fletrissement et le taux d'attaque. C'est apres 2 ans que les termites attaquent et fragmentent la litiere d'eucalyptus

碩士
淡江大學
土木工程學系碩士班
97
Trees in the city can supply oxygen, clean air and keep out radiations from the burning sun. In addition, these can adjust climate by absorbing radiations. Therefore, using the street trees to make city green has become the populace the hot topic of discussion.. The issue that the street trees roots destroyed the hardscape in the sidewalk (frame, pavement, curb) is everywhere in Taiwan. This kind of roots damage issue was constantly waste a lot of repairing budget. This article formulated an evaluation on the damage of sidewalk by street tree roots by looking back the investigating research by former people all over the world. Besides, it made up some ways which can prevent and cure this issue. Finally, hope the ways can provide you with the reference to the street trees planting and maintaining management. According to the research, it can generalize some results as follow: (1) In Taiwan: There are six factors have the positive relations with the sidewalk hardscape destruction degree, that is, tree height, diameter at breast height (dbh), bare roots, the ways of planting, the varieties of pavement, the destruction degree of hardscape. (2) The evaluation gives grades depend on the importance of the six effective degrees. With the great grades comes the great damage to the sidewalk hardscape. Among which, grade rules are made by the classified distance and the weight of the six evaluations which depend on the references (3) The point of the management of the street tree is preventing the roots destroy the hardscape around plant cave. It can start from the two aspects “prevent” and “cure”: “Prevent” is the most important and positive way, while “cure” is the negative way to redeem. (4) The first step:to score the damages (from first to fifth); and the scores cant let us know the effect of the sidewalk hardscape. It’s means the scores are more high, the damages are more serious. (5) In every step,the cores have two standards to score:the first step,if it lower than the fifty points, and we just make the prevent methods to drop the possibility of damage of the plants cave in the future; if it higher than the points, we should take the measure to cure and become the second of cores.The second step , if it more than twenty points, it suggests moving out the street trees.If it lower the points, we advise you that you trim the street tree roots.

碩士
國立臺灣大學
森林學系研究所
86
The object of this study is to observe the physiological influences and damages by salt stress to four native broad-leaved species, namely Palaquium formosanum, Pongamia pingamia, Garcinia spicata and Planchonella pinnata. This study were discussed (1)flooding salt water and salt spray effects in four native broad-leaved species. (2) flooding salt water, salt spray and machine hurt in Palaquium formosanum. The results show that in the parts of flooding salt water and salt spray, most damage came from flooding salt water treatment. The damage increased with increasing accumulation of Na+ and Cl-. When Na+ and Cl- content increased, proline accumulation induced, Na+/Ca2+ and Na+/K+ ratio was increased, but chloroplast content was decreased in four species. Parameters of T/R ratio, stem ground diameter and tree height growth are different in some species, like T/R ratio are significance difference by salt flooding treatment in Planchonella pinnata, both stem ground diameter and tree height growth were decreased by salt flooding treatment in Palaquium formosanum, stem ground diameter were decreased by salt flooding treatment in Pongamia pingamia. In correction analysis, there are height correction coefficient between Na+ and Cl- was more than 0.90, between Na+,Cl- and proline was more than 0.90 in all species. In salt flooding, salt spray and machine hurt treatment, we take Palaquium formosanum species as an example, the results show that machine hurt may inhibit diameter growth. salt spray and machine hurt can increased Na+ and Cl- into leaves. The findings will provide basic information for plant response to salt stress.

碩士
國立屏東科技大學
森林系
93
Wind is one of important physical factor in a forest ecosystem. It can affect morphology, growth and distribution of trees. In this study, tolerances to mechanical damages in leaves of 14 tree species were compared by monitoring leaf damage characteristics under wind speed of 3 m s-1. Results showed that light or brown lesions, deformities, tearing and shredding occurred when leaves of some wind-intolerant species were exposed to wind stress. Leaves of Bischofia javanica, Melanolepis multiglandulosa, Diospyros maritime, Machilus japonica, Schefflera octophylla and Ardisia sieboldii became lesions as the duration of wind stress increased. Percentages of mechanical damage in leaves of both B. javanica and M. multiglandulos were 54% and 45%, respectively. On the other hand, P. costalis, G. axillaries, Beilschmiedia tsangii and Myrica adenophora had compacted leaf structure, which might increase their ability to resist the mechanical damages by wind stress. The dehydration tolerances of the 14 species were also compared in this study. Results showed that there was a significant relationship between leaf mass per area (LMA) and dehydration tolerances of these species. The LMA values of P. costalis, L. akoensis and N. nagi were between 12.0-22.4 mg cm-2, and their injury indices of leaf water potential at -4.0 MPa were only 21-34%. In comparison, the LMA values of B. javanica and M. multiglandulosa were between 4.1-6.1 mg cm-2 with injury indices of 77-79%. These findings revealed that with higher LMA, leaves may have higher dehydration tolerance ability. In addition, there were significant relationship between the ability of mechanical damage tolerance and leaf structure, LMA, single leaf area, leaves dehydration tolerance and leaf morphology index (LMA/leaf area). Those species with leaves of higher LMA and larger leaf morphology index could better tolerant mechanical damages caused by strong winds.

碩士
中華大學
土木工程學系碩士班
100
Whether the water is polluted or not, it can be identified by its salinity or alkalinity. For the salt damage, the electrical conductivity represents the dissoluble inorganic salts in water. For the alkali damage, the Sodium Adsorption Ratio (SAR) is used to identify the classification of irrigation water quality and to know the harm and range of the pollution using the graphical classification of relation between electrical conductivity and SAR in the irrigation water quality management guide. This study adopted the historical water examination data provided by Hsinchu Irrigation Association, and used water temperature (T), pH, electrical conductivity (EC), Ca2+ and Na+ as input factors. The regression analysis and the genetic algorithm combined with operation tree (GAOT) were used and compared. The data were divided into 25 data of training simulation and 13 data of test simulation, and the relation scheme was built. The linearly correlation coefficient (CC) value, Root Mean Squared Error (RMSE) and the relevance between the actual value of SAR and the predicted value of SAR were used to check the quality of analytic methods. Finally, according to the scatter diagram result, the predictability of GAOT analysis is better than that of regression analysis, and it is feasible to use it and real-time monitoring data of water quality to estimate the salt and alkali damage. It can replace traditional manual on-site sampling for examination, which is labor and time consuming.

碩士
國立臺灣大學
園藝學研究所
99
The study investigate the application of color-leaf plants in green land of parks, the layout model of common-used street trees, and the improvement of root-damage from street trees in Kaohsiung city to understand the miss-layout of park plants and street-trees and the improvement methods. Further, to provide a guideline of greening-plants selection and management / maintenance improvement to Kaohsiung city for layout of parks. We surveyed the layout of color-leaf plants of 20 parks in Kaohsiung city and indicated a top 10 color-leaf plants which were frequently used: Duranta repens cv. Golden Leaves, Ficus microcarpa. Cv.’Golden leaves, Cordyline fruticosa , Codiaeum variegatum, Sansevieria trifasciata cv. Laurentii, Ligustrum sinense cv. ‘Variegatum’, Alpinia speciosa cv ‘Variegata’, Acalypha wilkesiana, Breynia nivosa cv. ‘Roseo-picat’, and Crossostephium chinense. The using frequency of color-leaf plants in each park is equal to 4.75. The parks planted with less than 3 kinds of color-leaf plants were accounted for about 55% (11 of 20 parks), which with 4 to 5 species were about 20 % (4 of 20 parks), and which with more than 6 species were about 25 % (5 of 20 parks). The top 3 parks which used the most color-leaf plants were entirely the currently-established park, like “Tropical Botanical Garden” possessing of 17 species, “Labour Park” with 12 species, and “Aozihdi Urban Forest Park” with 10 species. Otherwise, “Gangshan Park” planted without the color-leaf plants. According to classification by plant species, the Duranta repens cv. Golden Leaves has the most planting-area about 412,245 m2 than the second species Ficus microcarpa. Cv.’Golden leaves’with 64,650 m2 and the third species Cordyline fruticosa with 29,325 m2. As a whole, totally only 23 kinds of color-leaf plants were planted in 20 parks of Kaohsiung city we were sampled. So, to enhance the application of color-leaf plants in park design is indeed necessary. The ornamental quality of color-leaf plants was categorized into 5 levels by growth index. Their quality were scored and presented sequentially in accordance with the overall growth performance: Sansevieria trifasciata cv. Laurentii.as 3.5 scores, Duranta repens cv. Golden Leaves as 2.88 scores, Codiaeum variegatum as 2.78 scores, Ficus microcarpa. Cv.’Golden leaves’ as 2.6 scores, and Cordyline fruticosa as 1.65 scores. Furthermore, all the color-leaf plants planted in park of Kaohsiung city were never to be up to the standard of watch according to their lower growth index 2.69. The soil hardness of 20 parks in Kaohsiung city were calculated and averaged into 18.93㎏/cm2 which was belonging to normal hardness range from 10 to 22㎏/cm2. Of 20 parks surveyed in Kaohsiung city, only 1 park yielded a soil hardness value under 15㎏/cm2, 8 parks yielded value 15 to 18㎏/cm2, 4 parks yielded value 18 to 20㎏/cm2, 5 parks yielded value 20 to 22㎏/cm2, and 2 parks yielded value higher than 22 ㎏/cm2that exceed standards. With regard to the soil pH, the average pH of 20 parks was 7.49. Of 20 parks, “Mincyuan Park” and “Tropical Botanical Garden” has mild-acidic soil with pH 6.39 and 6.4, separately; northern and southern part of“Aozihdi Urban Forest Park” has alkaline soil with pH 8.26 and 8.2, separately. All of these 4 parks which without reasonable pH were unfavorable to the growth of plants. Generally, soil is mild acidic, but soils in park of Kaohsiung city were alkaline. We suggested that the waste cement from civil constructions mixed into soil lead to the alkalization of soils. About EC (electrical conductivity) value of soil, average EC value of 20 parks was 498.3 μS/㎝ which was poor in nutrition. Among 20 parks, soil EC of southern part of“Aozihdi Urban Forest Park” and northern part of “Aozihdi Urban Forest Park” were the highest with value of 1296 μS/㎝ and 1296 μS/㎝, separately, which were beneficial to plant growth. Moreover, soil EC of“忠孝 Park”(274.5 μS/㎝), “Siaogang Park” (281.6 μS/㎝) , and“Labour Park” (292.2 μS/㎝) were relative lower than others, which were disadvantageous to plant growth. Therefore, soil EC value is highly correlated to constructive times that the newer park with the higher EC values. About soil water content (SWC), the average water content of soil in 20 parks of Kaohsiung city was 15.98%. Of 20 parks, “Sing Ren Park”has the highest SWC with 31.1%, and“Birthday Park” and northern part of“Aozihdi Urban Forest Park” were the second and third with 22.5% and 20.6%, separately. Conversely, “Mincyuan Park” and“Siaogang Park”were under lower SWC which with 6.28% and 9.36%, separately. Both these two parks with insufficient water content were resulted in low growth quality to plants, like serious leaf-drop and chlorosis on lower-leaf of shrubs and critical withered of turfs. Hence, it is recommended to improve the management of water and fertilizers to enhance ornamental qualities. With regard to the street trees, the maintenance and management of growth were generally well. The questionnaire results about favorite plant layouts indicated that the No.1 layout is the parterre design under the street trees in Speed separation strip in Sihwei 3nd Rd, the No.2 is the green-belt design with colorful seasonal flowers under street trees in Jiouru 1st Rd, and the No.3 is the planting of perennial green plants under boulevard in Minzu 2nd Rd. The tree species applied in street-tree layouts in Kaohsiung city were mainly use of Alstonia scholaris and Pterocarpus indicus, others included the Cinnamomum camphora, Swietenia macrophylla, and Sterculia foetuda. These above tree species were have identical characters which were obtained easily, grew rapidly, with strong adaptation ability, and maintain/manage simply. Recent years, Kaohsiung city government promoted the “multi-layer planting” to layout the street-tree in ten major roadway in Kaohsiung city. For example, open space under street-trees were planted with almost 90% of Duranta repens cv. Golden Leaves and/or perennial Ixora williamsii, two extremities of traffic island were reinforced in layout of seasonal flowers to increase the color and bio-diversity of roadways to promote the sense of urban beauty. In part of root-damage (RD) improvement in Kaohsiung city, the RD of Cinnamomum camphora in Sihwei Rd, Mincyuan Rd, and Minsheng Rd was improved by replacement of RD trees with plants the belt; RD Fious mircocarpa in Jhongiheng Rd, RD Bombax ceiba in Lin SenRd, ChenggongRd, and Zhongxiao Rd were improved by transplanting the RD trees to the nursery of Kaohsiung city government or enlarging the original plant-hole or designing into plants the belt. After inquire about and investigate to the maintenance office of bureau of public works of Kaohsiung city government, the results indicated that the street development, like improvement of street tree and pedestrian space, will continually conducted to decrease the root damage of street from street trees.

碩士
東海大學
景觀學系
89
This study surveys total 2,079 street trees, which are including 10 species, in Taipei city. There are several primary purposes of this study. They are─first, to understand the root damage of street trees in urban area; second, to induct the reasons which cause the situation of root damage; third, to investigate the difference of root damage by different street-tree species in frame, pavement and curbs of sidewalk. Utilizing those discoveries from above researches, this study intends to provide some advice for species-selection, planting techniques and maintenance standard of street trees. There are five conclusions below, which are drawn by summarizing the discoveries of this study: 1. There are significant differences of root damage from different species of street trees. 2. The level of root damage of sidewalk is corresponding to DBH . 3. If the percentage of surface root of a tree species is higher, the root damage is more serious. Frames and curbs damage correlates closely with the percentage of surface root. 4. As the planting position is farer from the pavement, the damage degree of sidewalk will be decreased. 5. If the distance from planter to curbs was further, the influence of root damage is lower. There are several suggestions drawn from this study for species-selection, planter and maintenance standard of street trees. 1. Species-selection The identified tree species with higher degree of sidewalk damage should avoid. Unless those species are under a strict size control; for example, they are trimmed frequently, they might still have the threats of pavement damage. 2. Planter For the planter size, it should be enlarged separately, or combines separate one to become a planter-belt. The soil type should be have high capacity of air and water. For those street trees, which have wide elegant crowns, with shallow roots, which cause the frame, pavement and curb damage; the planters should install root-barrier as preservation of surrounding structure. 3. Maintenance It is necessary to have a regular investigation of the air capacity and drainage situation of the soil in the planter; therefore, we can prevent that the roots grow upward and cause root damage due to the dense and hard soil, which make the root hard to grow downward. After the tree is planted, avoid to change the level of soil because it might stimulate roots growing upward and outward from planter. For further research, try to investigate other tree species and items, such as soil, in different location or characteristic space to have a better understanding of the root damage of street trees. Keywords: street tree, root damage, sidewalk, frame, pavement, curbs

Increasing productivity, reducing cost, reducing soil damage, reducing the impact of harvesting on standing tree and regeneration are all very important objectives in ground skidding system in the management of the Hyrcanian forest. The research carried out to obtain these objectives included four logging methods, tree length method (TLM), long length method (LLM), short length method (SLM), and wood extraction by mule (mule) in northern Iran. In order to determine the cost per unit, time study techniques were used for each harvesting method, time study data are shifted to logarithmic data based on 10. On the basis of the developed models simulated, 11 skidding turns are simulated and the unit cost are estimated depending on the diameter of the log (DL), skidding distance (SD), and the winching distance (WD) for 11 different cycles with TLM, LLM and SLM. The results showed that on average, the net costs per extraction of one cubic meter of wood were 3.06, 5.69, 6.81 and 34.36 €/m3 in TLM, LLM, SLM and mule. The costs depending on diameter of log (DL), skidding distance (SD) and winching distance (WD) showed that the most economical alternative for Northern Iran is TLM. In the cut-to-length system, the costs of both alternatives LLM, SLM were significantly dependent on DL. , thus the result of this study suggests that as long as the diameter of the felled trees is less than 40 cm, the cut-to-length system is not an economical alternative, whilst the cut-to-length method can be applied for trees with a diameter more than 40 cm. Where diameters are more than 40 cm TLM it is more economical than SLM, however it was not significantly different. Depending on SD in short skidding distance SLM is preferable to LLM but in cases of long skidding distance LLM is more economical than SLM. The winching distance affect was not a factor on cost. To assess the damage on seedlings and standing trees a 100% inventory method was employed in pre-hauling and post-hauling, alongside of skidding trails, winching strips and mule hauling with a 12m width. To chose the best alternative depending on standing damage the Analysis of multiple criterial approval (MA) was applied. The amount of trees damaged by winching operation were 11.89% in TLM, 14.44% in LLM 27.59%, SLM and 0 stem and by skidding operation were 16.73%, 3.13% and 8.78% of total trees in TLM, LLM and SLM. In the winching area about 14%, 20%, 21% and 6 % of the total regeneration was damaged by TLM, LLM, SLM and mule and the skidding operation damaged 7.5% in TLM, 7.4 % LLM and 9.4% in SLM. The friendliest alternative to residual standing was mule but in manual method (where the wood extraction is done by skidder) MA showed that the best alternative depending on residual damage is LLM. To determine the degree of soil compaction a core sampling technique of bulk density was used. Soil samples collected from the horizontal face of a soil pit at 10 cm depth soil core, at 50m intervals on skid trials, in winching strips and control are (no vehicles pass) a soil sample was taken at 10m intervals in the hauling direction of the mule. In order to determine the post-harvesting extent of disturbance on skidding trails by skidding operations, the disturbed widths were measured at 50 m intervals along the skid trails. In the winching area, where the winched logs created a streak of displaced soil, the width of the displaced streak was measured at 5 m interval along the winching strip. In mule hauling operations the width of a streak created by a mule foot track was measured at 10 m intervals. To compare increased average bulk density between alternatives one way The ANOVA, Duncan test and Dunnett t-test with a 95 % confidence level were used. A General linear model was applied to relate the increasing bulk density and the slope gradient. To realize the correlation between the increment of soil bulk density and the slope gradient and the correlation between the soil compaction and soil moisture content (%) The Pearson correlation test was applied. To choose the best alternative (in manual method) a MA test was applied again. The bulk density on the skidding trail increased 51 % for 30 skidding turn, 35 % for 31 skidding turn (one unloaded and one loaded pass) and 46% for 41 skidding turn. Results of ANOVA (p < 0.05) show significant differences of bulk density between alternatives. Duncan test and the Dunnett t-test indicated that the increasing soil bulk density was not significant between control samples and winching strip of TLM and extraction by mule samples. The general linear modeling and Pearson correlation test results indicated that the slope gradient had an insignificant effect on soil compaction, whilst the Pearson test indicates a medium negative correlation between soil compaction and percentage of soil moisture. By ground-based winching operation 0.07%, 0.03%, 0.05% and 0.002% of the total area and by ground based skidding operation 1.21%, 1.67%, 0.81% and 0.00% of total area was disturbed and compacted in TLM, LLM, SLM and mule. The Pearson correlation results show that the width of disturbed area was significantly influenced by the diameter of logs and length of logs (p ˂ 0.05), but there is no significant correlation between soil disturbance width and slope. The results of analysis of MA showed that soil compaction was not related to logging method but sensitivity analysis of MA shows that LLM and TLM are both preferable to SLM.