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Large wood (LW) recruitment, transport, and storage were evaluated over a century in Gregory and Riley creeks (Haida Gwaii, British Columbia) by modeling a reach-scale LW budget using two frameworks for output: LW loss through dec...
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Large wood (LW) recruitment, transport, and storage were evaluated over a century in Gregory and Riley creeks (Haida Gwaii, British Columbia) by modeling a reach-scale LW budget using two frameworks for output: LW loss through decay and downstream transport, and loss through depletion. At reach and at watershed scales, mass movement and bank erosion dominated inputs, and fluvial transport was an important flux term in several reaches. Large wood recruitment by mortality was relatively minor in comparison. Large proportions of the in channel LW were stored in jams with a mean age of 40-50 years. Overall, both modeling approaches yielded reasonable stored LW predictions in the study creeks, with the omission/inclusion of transport responsible for the largest differences between models. Modeled storage generally was within 30% of that measured in the field, and our results illustrate the large temporal variation in storage resulting from episodic inputs of LW from hillslopes. (C) 2016 Elsevier B.V. All rights reserved.
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The annual fluvial export of large wood (LW) was monitored by local reservoir management offices in Japan. LW export per unit watershed area was relatively high in small watersheds, peaked in intermediate watersheds, and decreased...
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The annual fluvial export of large wood (LW) was monitored by local reservoir management offices in Japan. LW export per unit watershed area was relatively high in small watersheds, peaked in intermediate watersheds, and decreased in large watersheds. To explain these variations, we surveyed the amount of LW with respect to channel morphology in 78 segments (26 segments in each size class) in the Nukabira River, northern Japan. We examined the differences in LW dynamics, including its recruitment, transport, storage, and fragmentation and decay along the spectrum of watershed sizes. We found that a large proportion of LW produced by forest dynamics and hillslope processes was retained because of the narrower valley floors and lower stream power in small watersheds. The retained LW pieces may eventually be exported during debris flows. In intermediate watersheds, the volume of LW derived from hillslopes decreased substantially with reductions in the proportion of channel length bordered by hillslope margins, which potentially deliver large quantities of LW. Because these channels have lower wood piece length to channel width ratios and higher stream power, LW pieces can be transported downstream. During transport, LW pieces are further fragmented and can be more easily transported. Therefore, the fluvial export of LW is maximized in intermediate watersheds. Rivers in large watersheds, where the recruitment of LW is limited by the decreasing hillslope margins, cannot transport LW pieces because of their low stream power, and thus LW pieces accumulate at various storage sites. Although these stored LW pieces can be refloated and transported by subsequent flood events, they may also become trapped by obstacles such as logjams and standing trees on floodplains and in secondary channels, remaining there for decades and eventually decaying into fine organic particles. Thus, the fluvial export of LW pieces is low in large watersheds.
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This work aimed to evaluate the effect of heat treatment on the physical properties of wood from Buchenavia sp. The heat treatments were carried out at temperatures of 180 °C and 200 °C for 2 h. Apparent density (AD), basic dens...
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This work aimed to evaluate the effect of heat treatment on the physical properties of wood from Buchenavia sp. The heat treatments were carried out at temperatures of 180 °C and 200 °C for 2 h. Apparent density (AD), basic density (BD), porosity (Ф), mass loss, longitudinal (LS), radial (RS), tangential (TS) and volumetric (VS) shrinkages and anisotropic factor (AF) were determined. The lowest values of basic density (0.67 g cm-3), apparent density (0.77 gcm-3), and porosity (43.3%) were observed for the wood treated at a temperature of 200 °C. Mass losses increased with increasing temperature and the highest values were observed under the condition of 200 °C (9.3%). The LS and AF was not affected by heat treatments. The mean values for RS (3.1%), TS (5.1%), and VS (9.1%) were reduced after the performance of heat treatments at temperatures of 180°C and 200°C, which did not differ from each other. The thermal treatments were able to reduce the dimensional instability of Buchenavia sp. Thermal treatments enhance the use of less prestigious Amazonian woods in the civil construction market.
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Die steigende Nachfrage nach Holz und der damit verbundene, verstarkte Holzeinschlag in Europa sowie eine veranderte Waldwirtschaft hin zu laubholzreichen Mischbestanden fuhren zu einer Verknappung des Holzangebots. Ein Beispiel e...
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Die steigende Nachfrage nach Holz und der damit verbundene, verstarkte Holzeinschlag in Europa sowie eine veranderte Waldwirtschaft hin zu laubholzreichen Mischbestanden fuhren zu einer Verknappung des Holzangebots. Ein Beispiel einer bislang kaum genutzten Holzfraktion ist Altholz. Nach einer Einfuhrung in die allgemeine Holzversorgung in Europa wird auf die spezielle Situation der Altholznutzung in Deutschland eingegangen, deren rechtliche aber auch tatsachliche Situation. Hierbei werden besonders die moglichen Kontaminationen und Storstoffe des Altholzes und deren Herkunft behandelt.
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Understanding the macroscopic structure of wood and its formation is essential to identifying wood and evaluating its properties and quality. Depending on genetic background, environmental conditions, and tree developmental stage,...
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Understanding the macroscopic structure of wood and its formation is essential to identifying wood and evaluating its properties and quality. Depending on genetic background, environmental conditions, and tree developmental stage, the macroscopic structure of wood can vary greatly and produce specific macroscopic signatures. Here, a comprehensive outline of the wood’s macroscopic structure and the features that can be used to identify wood by macroscopic examination is presented. The planes of observations are first depicted, and the fundamental differences between softwoods and hardwoods are outlined. Then, all the different cell characteristics, arrangements, and distributions that can be macroscopically observed are illustrated with their influence on wood figure and texture and non-anatomical features.
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This study sought to develop a method to quantify tension wood areas in stem discs. It was suggested that the shiny appearance of beech (Fagus sylvatica L.) could provide an indication of tension wood. Each of 21 stem discs were d...
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This study sought to develop a method to quantify tension wood areas in stem discs. It was suggested that the shiny appearance of beech (Fagus sylvatica L.) could provide an indication of tension wood. Each of 21 stem discs were digitised and the images analysed. Small areas of the discs were selected, and from these areas, anatomical sections were stained with astra-blue and safranine and the stained sections were compared with the wood disc images. The analysis showed that the shape of shiny areas and tension wood were similar; moreover, the measured ratios of shiny wood and tension wood were in good agreement. This confirms the assumption that in Fagus sylvatica shiny wood corresponds to tension wood.
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Large wood (LW) abundance, longitudinal distribution and mobilization were studied in the Vuelta de la Zorra channel draining a third order catchment located in the Coastal mountain range of southern Chile. Seventy-five percent of...
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Large wood (LW) abundance, longitudinal distribution and mobilization were studied in the Vuelta de la Zorra channel draining a third order catchment located in the Coastal mountain range of southern Chile. Seventy-five percent of the 586.8 ha study catchment area is covered by evergreen native rainforests, 24% by Eucalyptus nitens plantations and the remaining 1% are different sites were native tree and shrub species are regenerating in areas that were prepared for forest replacement in the late 1980s but finally left unplanted. In a segment, 1557 m in length, surveyed between November 2008 and February 2009, a total of 484 pieces representing 181 m(3) of LW were measured. Using bankfull width and length this volume corresponds to 109 m(3) ha(-1) or 11.6 m(3) 100 m(-1). LW was distributed along the channel in correlation with bankfull width. The channel segment was re-surveyed in December 2009 and we found that after one winter season 12% of the LW were transported downstream the river channel and 9 new wood elements were recruited. The LW traveled distance and traveled distance/piece diameter ratio decreased with increasing piece length/mean bankfull ratio. These results contribute to understand the complexity of LW abundance, mobilization and recruitment processes, and their effects on channel morphology, sediment routing and ecology in Chilean catchments
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Large wood (LW) abundance, longitudinal distribution and mobilization were studied in the Vuelta de la Zorra channel draining a third order catchment located in the Coastal mountain range of southern Chile. Seventy-five percent of...
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Large wood (LW) abundance, longitudinal distribution and mobilization were studied in the Vuelta de la Zorra channel draining a third order catchment located in the Coastal mountain range of southern Chile. Seventy-five percent of the 586.8 ha study catchment area is covered by evergreen native rainforests, 24% by Eucalyptus nitens plantations and the remaining 1% are different sites were native tree and shrub species are regenerating in areas that were prepared for forest replacement in the late 1980s but finally left unplanted. In a segment, 1557 m in length, surveyed between November 2008 and February 2009, a total of 484 pieces representing 181 m(3) of LW were measured. Using bankfull width and length this volume corresponds to 109 m(3) ha(-1) or 11.6 m(3) 100 m(-1). LW was distributed along the channel in correlation with bankfull width. The channel segment was re-surveyed in December 2009 and we found that after one winter season 12% of the LW were transported downstream the river channel and 9 new wood elements were recruited. The LW traveled distance and traveled distance/piece diameter ratio decreased with increasing piece length/mean bankfull ratio. These results contribute to understand the complexity of LW abundance, mobilization and recruitment processes, and their effects on channel morphology, sediment routing and ecology in Chilean catchments
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Wood deposited in streams provides a wide variety of ecosystem functions, including enhancing habitat for key species in
stream food webs, increasing geomorphic and hydraulic heterogeneity and retaining organic matter. Given the s...
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Wood deposited in streams provides a wide variety of ecosystem functions, including enhancing habitat for key species in
stream food webs, increasing geomorphic and hydraulic heterogeneity and retaining organic matter. Given the strong role
that wood plays in streams, factors that influence wood inputs, retention and transport are critical to stream ecology. Wood
entrapment, the process of wood coming to rest after being swept downstream at least 10 m, is poorly understood, yet importan
for predicting stream function and success of restoration efforts. Data on entrapment were collected for a wide range of natura
wood pieces (n D 344), stream geomorphology and hydraulic conditions in nine streams along the north shore of Lake Superio
in Minnesota. Locations of pieces were determined in summer 2007 and again following an overbank stormflow event in fal
2007. The ratio of piece length to effective stream width (length ratio) and the weight of the piece were important in a multiple
logistic regression model that explained 25% of the variance in wood entrapment. Entrapment remains difficult to predict in
natural streams, and often may simply occur wherever wood pieces are located when high water recedes. However, this study
can inform stream modifications to discourage entrapment at road crossings or other infrastructure by applying the mode
formula to estimate the effective width required to pass particular wood pieces. Conversely, these results could also be used
to determine conditions (e.g. pre-existing large, stable pieces) that encourage entrapment where wood is valued for ecologica
functions. Copyright 2010 John Wiley & Sons, Ltd.
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Information on the potential wood supply is important for the wood industry. In this study, the future development of growing stock, cutting potential and wood properties corresponding to the regional scenario of North Karelian Fo...
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Information on the potential wood supply is important for the wood industry. In this study, the future development of growing stock, cutting potential and wood properties corresponding to the regional scenario of North Karelian Forest Programme 2006-2010 was analysed. The simulations were performed by employing the Finnish MELA system together with the sample plot and tree data of the 9(th) Finnish National Forest Inventory (NF19) as initial data for the simulations. Disc-based models for basic wood density, proportion of latewood and fibre length of Norway spruce and Scots pine in Sweden were calibrated and integrated into the MELA system. The wood properties at breast height of both harvested and standing trees were analysed in different strata (age, site type and cutting method) during the scenario period of 50 years (2002-2052). The average wood properties within the same strata varied only slightly over time. However, the results for different strata differed considerably. In general, wood density, fibre length and proportion of latewood increased, on average, as it function of tree age and along with a decrease in site fertility (excl. wood density and proportion of latewood in harvested Norway spruce in the first case and fibre length in the latter case for both species). For trees less than 80 years, properties in harvested trees were equal to or slightly greater than those of standing trees. The values for clear-cuttings were greater or equal to those of thinnings (excl. wood density and proportion of latewood in Norway spruce). The study demonstrates the value of model-based analyses utilising NFI tree measurements in regions that are considered to be Sources of raw material.
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