EFFECTS OF MECHANICALLY GENERATED SLASH PARTICLE SIZE ON PRESCRIBED FIRE BEHAVIOR AND SUBSEQUENT VEGETATION EFFECTS

Forest managers have begun to restore ecosystem structure and function in fire-prone ecosystems that have experienced fire exclusion, commodity based resource extraction, and extensive grazing during much of the 20th century. Mechanical thinning and prescribed burning are the primary tools for thinning dense stands and restoring pre-settlement forest structure, reducing the likelihood of devastating crown fires. Mechanical thinning can be costly when trees are nonmerchantable and prescribed burning can be risky unless fuel loadings are first reduced. Furthermore, stands that remain dense after commercial thinning can produce undesirable wildland fire- or even prescribed fire- effects on vegetation and soils. Land managers are interested in using mastication equipment (Fig. 1) for thinning nonmerchantable trees as a means of restoring structure and function to dry forest ecosystems. However, it is unknown how the addition of mechanically derived slash influences potential fire behavior and fire effects. The objectives of this project were to test the effectiveness of mastication effort (defined as time needed to break fuels into smaller pieces) to 1) thin dense stands of dry coniferous forest within historically frequent, low-severity fire regimes (Fig. 1) and 2) create surface fuel beds that produce prescribed fire behavior with positive effects on residual trees, understory vegetation, and soils. Specifically, we asked the following questions: (1) How does slash particle size and fuel bed depth affect fire intensity and severity? (2) How do different mastication efforts and subsequent prescribed fire affect overstory vegetation? (3) Does soil heating change from burning different types of masticated slash? and (4) What are the differences in production costs among levels of mastication effort

Digital encoding of black and white facsimile signals

As the costs of digital signal processing and memory hardware are decreasing each year compared to those of transmission, it is increasingly economical to apply sophisticated source encoding techniques to reduce the transmission time for facsimile documents. With this intent, information lossy encoding schemes have been investigated in which the encoder is divided into two stages. Firstly, preprocessing, which removes redundant information from the original documents, and secondly, actual encoding of the preprocessed documents. [Continues.

Natural regeneration of broadleaved tree species in southern Sweden

The objective of the present thesis was to examine the effects of silvicultural treatments and seed dispersal from surrounding stands on the establishment of natural regeneration of broadleaved tree species in southern Sweden. Most of the broadleaved tree species that occur naturally in forests in southern Sweden were studied but birch (Betulapendula Ehrh.1 B. pi~besceizs Roth) was the most common species and present in equal numbers in all studies. The wind dispe.rsa1 of see.ds of se.ven species was studied and great variations were found. This could mainly be explained by differences in seed morphology. The effect of soil scarification was examined in all five studies and was generally found to be positive for the establishment of the studied broadleaved species. However, in some cases the scarification was not positive for the establishment. The reason for t l i s was hypothesised to be that the seed supply was limited, or an effect of large and/or animal-dispersed seeds. The effect of shelterwood w a s examined in three studies and was found to be positive for animal-dispersed species but negative for shade-intolerant species, although a sparse shelterwood can be used to rcgcncratc birch. Slash removal was included in onc study and found to be positive for thc cstnblishrncnt of birch. This thcsis showccl that regeneration trcatmcnts can be used to incrcasc the e.stablishnent of naturally regene.rated broadleaved tree seedlings, but the stand structure and species composition must be regulated with pre-commercial thinning. However, the effect of variations in seed production and seed dispersal must be closely examined from a time and a space perspective prior to any forecasts regarding the effects of regeneration trcatrn

Print-Scan Resilient Text Image Watermarking Based on Stroke Direction Modulation for Chinese Document Authentication

Print-scan resilient watermarking has emerged as an attractive way for document security. This paper proposes an stroke direction modulation technique for watermarking in Chinese text images. The watermark produced by the idea offers robustness to print-photocopy-scan, yet provides relatively high embedding capacity without losing the transparency. During the embedding phase, the angle of rotatable strokes are quantized to embed the bits. This requires several stages of preprocessing, including stroke generation, junction searching, rotatable stroke decision and character partition. Moreover, shuffling is applied to equalize the uneven embedding capacity. For the data detection, denoising and deskewing mechanisms are used to compensate for the distortions induced by hardcopy. Experimental results show that our technique attains high detection accuracy against distortions resulting from print-scan operations, good quality photocopies and benign attacks in accord with the future goal of soft authentication

Techniques for document image processing in compressed domain

The main objective for image compression is usually considered the minimization of storage space. However, as the need to frequently access images increases, it is becoming more important for people to process the compressed representation directly. In this work, the techniques that can be applied directly and efficiently to digital information encoded by a given compression algorithm are investigated. Lossless compression schemes and information processing algorithms for binary document images and text data are two closely related areas bridged together by the fast processing of coded data. The compressed domains, which have been addressed in this work, i.e., the ITU fax standards and JBIG standard, are two major schemes used for document compression. Based on ITU Group IV, a modified coding scheme, MG4, which explores the 2-dimensional correlation between scan lines, is developed. From the viewpoints of compression efficiency and processing flexibility of image operations, the MG4 coding principle and its feature-preserving behavior in the compressed domain are investigated and examined. Two popular coding schemes in the area of bi-level image compression, run-length and Group IV, are studied and compared with MG4 in the three aspects of compression complexity, compression ratio, and feasibility of compressed-domain algorithms. In particular, for the operations of connected component extraction, skew detection, and rotation, MG4 shows a significant speed advantage over conventional algorithms. Some useful techniques for processing the JBIG encoded images directly in the compressed domain, or concurrently while they are being decoded, are proposed and generalized; In the second part of this work, the possibility of facilitating image processing in the wavelet transform domain is investigated. The textured images can be distinguished from each other by examining their wavelet transforms. The basic idea is that highly textured regions can be segmented using feature vectors extracted from high frequency bands based on the observation that textured images have large energies in both high and middle frequencies while images in which the grey level varies smoothly are heavily dominated by the low-frequency channels in the wavelet transform domain. As a result, a new method is developed and implemented to detect textures and abnormalities existing in document images by using polynomial wavelets. Segmentation experiments indicate that this approach is superior to other traditional methods in terms of memory space and processing time

Remote sensing applications in forestry - The development of an earth resources information system using aerial photographs and digital computers Annual progress report

Earth resources information system using aerial photographs and digital computer

Distortions to Global Agricultural Markets: What Next?

A decline in governmental distortions to agricultural and other trade since the 1980s has contributed to economic growth and poverty alleviation globally. But new modeling results suggest that has taken the world only three-fifths of the way towards freeing merchandise trade, and that farm policies are responsible for 70 percent of the global welfare cost of remaining distortions to goods markets as of 2004. Meanwhile, new drivers are affecting the mean and variance of world prices of farm products, including biofuel mandates and subsidies, climate change mitigation policies and adaptation, water institution and policy developments, difficulties in concluding a multilateral Doha Round agricultural agreement at the WTO, and policies relating to transgenic foods. This paper reviews trends and fluctuations in past distortions to agricultural incentives, speculates on how they might evolve in coming decades alongside other market developments, and draws out implications for Australia.Distorted incentives, agricultural and trade policy reforms, Asia-Pacific region

Urban Public Transport Delivery in Australia: Issues and Challenges in Retaining and Growing Patronage

Urban public transport continues to be a high priority social obligation of governments throughout the world. In some jurisdictions it is the prime responsibility of national governments, while in other localities it is a state or local responsibility. To varying degrees, public and private organizations deliver the services within a regulatory framework that has responsibility for the performance of suppliers in a wide range of market settings. Increasingly government subsidy support is being aligned to the patronage levels and market share of public transport. This paper focuses on the challenges involved in retaining and growing patronage in the presence of the dominant automobile. We focus primarily on bus and rail services but recognise the valuable role of ferries and taxis in the delivery of public transport

POORMAN LICK WEST SFA 2008

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