scholarly journals Projected decrease in wintertime bearing capacity on different forest and soil types in Finland under a warming climate

2018 ◽  
Author(s):  
Ilari Lehtonen ◽  
Ari Venäläinen ◽  
Matti Kämäräinen ◽  
Antti Asikainen ◽  
Juha Laitila ◽  
...  
Keyword(s):  
Bearing Capacity ◽  
21St Century ◽  
Climate Model ◽  
Thick Layer ◽  
Timber Harvesting ◽  
Forest Harvesting ◽  
Frozen Soil ◽  
Soil Types ◽  
Soil Frost ◽  
Wood Harvesting

Abstract. Trafficability in forest terrain is largely determined by ground-bearing capacity and it is thus one of the most important issues in timber harvesting. In winter, the bearing capacity is mainly determined by soil frost. Particularly on peatland forests bearing capacity is poor under unfrozen conditions. The bearing capacity of forest truck roads is similarly affected by ground frost. Already 20 cm thick layer of frozen soil or 40 cm layer of snow on the ground can carry in Finnish forest conditions heavy machines in forest harvesting. In this work, we studied the impacts of climate change on soil frost conditions, and consequently on ground-bearing capacity of soils from the timber harvesting point of view. The number of days with good wintertime bearing capacity was modelled by using a soil temperature model and wide set of downscaled climate model data until the end of the 21st century. The model was optimized for different forest and soil types. The results show that by the mid-21st century, the wintertime bearing season length decreases in Finland most likely by about one month. The decrease in soil frost and wintertime bearing capacity will be more pronounced during the latter half of the century when drained peatlands may virtually lack soil frost in most of winters in southern and western Finland. The projected decrease in the bearing capacity, accompanied with increasing demand for wood harvesting from drained peatlands, induces a clear need for the development of new sustainable and efficient logging practices for drained peatlands.

scholarly journals Projected decrease in wintertime bearing capacity on different forest and soil types in Finland under a warming climate

2019 ◽  
Vol 23 (3) ◽  
pp. 1611-1631 ◽  
Author(s):  
Ilari Lehtonen ◽  
Ari Venäläinen ◽  
Matti Kämäräinen ◽  
Antti Asikainen ◽  
Juha Laitila ◽  
...  
Keyword(s):  
Bearing Capacity ◽  
21St Century ◽  
Climate Model ◽  
Thick Layer ◽  
Timber Harvesting ◽  
Snow Accumulation ◽  
Point Of View ◽  
Frozen Soil ◽  
Soil Types ◽  
Soil Frost

Abstract. Trafficability in forest terrain is controlled by ground-bearing capacity, which is crucial from the timber harvesting point of view. In winter, soil frost affects the most the bearing capacity, especially on peatland soils which have in general low bearing capacity. Ground frost similarly affects the bearing capacity of forest truck roads. A 20 cm thick layer of frozen soil or 40 cm thick layer of snow on the ground may already be sufficient for heavy forest harvesters. In this work, we studied the impacts of climate change on soil frost conditions and, consequently, on ground-bearing capacity from the timber harvesting point of view. The number of days with good wintertime bearing capacity was modelled by using a soil temperature model with a snow accumulation model and wide set of downscaled climate model data until the end of the 21st century. The model was calibrated for different forest and soil types. The results show that by the mid-21st century, the conditions with good bearing capacity will decrease in wintertime in Finland, most likely by about 1 month. The decrease in soil frost and wintertime bearing capacity will be more pronounced during the latter half of the century, when drained peatlands may virtually lack soil frost in most of winters in southern and western Finland. The projected decrease in the bearing capacity, accompanied with increasing demand for wood harvesting from drained peatlands, induces a clear need for the development of sustainable and resource-efficient logging practices for drained peatlands. This is also needed to avoid unnecessary harvesting damages, like rut formation on soils and damage to tree roots and stems.

scholarly journals Pemanenan Kayu Hutan Rakyat (Studi Kasus di Ciamis, Jawa Barat) Timber

2018 ◽  
Vol 12 (2) ◽  
pp. 142 ◽  
Author(s):  
Sukadaryati Sukadaryati ◽  
Yuniawati Yuniawati ◽  
Dulsalam Dulsalam
Keyword(s):  
Timber Harvesting ◽  
Forest Edge ◽  
Forest Harvesting ◽  
Utilization Efficiency ◽  
Community Forest ◽  
West Java ◽  
Community Forests ◽  
Wood Harvesting ◽  
Financial Benefits ◽  
Harvesting Techniques

Pemanenan kayu di hutan rakyat yang tepat guna dapat memberikan efisiensi pemanfaatan sumber daya hutan dan memberikan keuntungan finansial bagi pengelola hutan rakyat. Tulisan ini bertujuan untuk memberikan informasi kegiatan pemanenan kayu hutan rakyat studi kasus di daerah Ciamis (Jawa Barat) aspek penebangan, pengeluaran kayu dan efisiensi pemanfaatan kayu. Hasil penelitian kegiatan pemanenan kayu di areal hutan rakyat di Desa Kertabumi dan Bojonggedang, Kabupaten Ciamis menunjukkan bahwa: 1). Kegiatan penebangan pohon di hutan rakyat dilakukan menggunakan alat tebang chainsaw dengan kisaran produktivitas penebangan 4,880 m/jam-8,578 m/jam; 2). Kegiatan pengeluaran kayu di hutan rakyat dilakukan menggunakan sepeda motor yang dimodifikasi dengan kisaran produktivitas 0,753 m/jam-0,506 m/jam, dengan kisaran jarak pengeluaran kayu ke pinggir hutan 115 m-161 m; 3). Efisiensi pemanfaatan kayu di hutan rakyat berkisar 98,72%-99,14%; 4). Teknik pemanenan kayu di hutan rakyat masih meninggalkan tunggak yang cukup tinggi dan belum memperhatikan keselamatan kerja. Teknik pemanenan kayu di hutan rakyat masih memerlukan perbaikan terhadap tinggi tunggak penebangan. Sebaiknya pemilik hutan rakyat tidak menjual kayu kepada bandar dalam bentuk pohon yang masih berdiri. Pengeluaran kayu dengan sepeda motor masih memerlukan perbaikan desain khususnya terkait dengan konstruksi penyangga beban di bagian kiri dan kanan sepeda motor untuk mengurangi kecelakaan kerjaTimber Harvesting in Community Forest (Case Study in Ciamis, West Java)AbstractEfficient timber harvesting in community forests can provide efficient use of Naskah masuk (received): 30 Nopember 2017 forest resources and provide financial benefits for community forest Diterima (accepted): 27 Maret 2018 managers. This paper aims to provide information on forest harvesting activities in the Ciamis area (West Java), such as aspects of tree felling, timber extraction, and timber utilization efficiency. The results of research on timber KEYWORDS harvesting in community forest areas in Kertabumi and Bojonggedang community forests Villages, Ciamis District shows that: 1). Tree felling in community forest is timber harvesting conducted using chainsaw cutting tool with a logging productivity range of productivity efficiency 4.880 -8.578 m/hour; 2). Timber expenditures in community forests are work safety carried out using modified motorcycles with a productivity range of 0.7530.506 m/hr, with a range of wood clearance to forest edge 115 -161 m; 3). The efficiency of timber utilization in community forest is 98.72-99.14%; 4). Wood harvesting techniques in community forests still leave a fairly high stump and have not paid attention to safety. Timber harvesting techniques in community forests still require improvements to the high log stumps. It is recommended that owners of the community forest do not sell wood in the form of trees that still stands to "the bandar”. The expenditure of wood using motorcycles still requires the improvement ofits design especially related to the construction of load buffers on the left and right side of the motorcycle to reduce work accident.

Nonpoint-source nitrogen and phosphorus behavior and modeling in cold climate: a review

2010 ◽  
Vol 62 (10) ◽  
pp. 2277-2285 ◽  
Author(s):  
Cheng-Wei Han ◽  
Shi-Guo Xu ◽  
Jian-Wei Liu ◽  
Jian-Jun Lian
Keyword(s):  
Nonpoint Source Pollution ◽  
Climate Model ◽  
Soil Aggregates ◽  
Nonpoint Source ◽  
Frozen Soil ◽  
Cold Climate ◽  
Watershed Scale ◽  
Nitrogen And Phosphorus ◽  
Soil Frost ◽  
Freezing Soil

Pollution from nonpoint-source (NPS) nitrogen (N) and phosphorus (P) are the main causes of eutrophication in lotic, lentic and coastal systems. The climate of cold regions might play an important role in disturbing environmental behavior of NPS N and P, influencing simulation of watershed scale hydrologic and nonpoint-source pollution models. The losses of NPS N and P increase in regions of cold climate. In cold seasons, accumulations of N and P are accelerated in soil with increasing fine root and aboveground biomass mortality, decreasing plant nutrient uptake, as well as freezing soil. N and P transformation is disturbed by soil frost and snow. Moreover, factors such as physical disruption of soil aggregates, pollutant accumulation in snowpack, and snow melting can all increase the NPS N and P losses to the waterbody. Therefore, NPS N and P in first flush are more serious in cold climate. All these effects, especially frozen soil and snowpack, make great challenges to watershed scale hydrologic and nonpoint-source pollution models simulation in cold climate. Model improvements of snowmelt runoff, nutrient losses in frozen soil, as well as N and P behavior have been initiated and will be continued to evaluate in terms of their performances and suitability with different scale, hydrologic and geologic conditions in the future.

scholarly journals Trial performance of the zero waste harvesting method in three forest concession companies, Central Kalimantan Province, Indonesia

2021 ◽  
Vol 914 (1) ◽  
pp. 012061
Author(s):  
Dulsalam ◽  
Soenarno ◽  
Sukadaryati
Keyword(s):  
Conventional Method ◽  
Forest Products ◽  
Timber Harvesting ◽  
Forest Harvesting ◽  
Natural Forest ◽  
Central Kalimantan ◽  
Zero Waste ◽  
Wood Harvesting ◽  
Natural Production ◽  
Tree Length

Abstract Currently, natural forest management companies (concession permit of timber forest products utilization-natural forest/IUPHHK-HA) have implemented Reduced Impact Logging (RIL) technology but timber harvesting is still carried out using the conventional method. Tree length logging is an alternative method of harvesting wood in an effort to reduced waste and increases the efficiency of the utilization of timber forest products and the preservation of natural production forests. The potential for wood harvesting waste is estimated at 2.21 million m3year−1 and has remained left in the cutting compartment for decades. The purpose of this paper is to obtain technical and financial information about forest harvesting on a zero waste basis. Data collection was carried out by experimental methods. Productivity, efficiency, cost, and stand damage data were collected. The results of the research in three IUPHHK-HA in Central Kalimantan show that the zero waste logging method can reduced harvesting waste by 5.1% and increase the efficiency of wood utilization from 87.7-92.8%. Another advantage of the zero waste logging method is that the additional waste from the trunk above the first branch is about 5.8%. The productivity of the conventional method averaged 26.333 m3hour−1 at a cost of IDR 33,941 m−3 while the tree length logging method was 27.320 m3hour−1 at a cost of IDR 35,251 m−3. It is suggested that the tree length logging method be implemented in natural production forest harvesting.

scholarly journals Projected changes in haze pollution potential in China: an ensemble of regional climate model simulations

2017 ◽  
Vol 17 (16) ◽  
pp. 10109-10123 ◽  
Author(s):  
Zhenyu Han ◽  
Botao Zhou ◽  
Ying Xu ◽  
Jia Wu ◽  
Ying Shi
Keyword(s):  
Regional Climate Model ◽  
21St Century ◽  
Climate Model ◽  
Regional Climate ◽  
River Delta ◽  
Central China ◽  
Future Climate Change ◽  
Pollution Potential ◽  
Pollution Risk ◽  
Haze Pollution

Abstract. Based on the dynamic downscaling by the regional climate model RegCM4 from three CMIP5 global models under the historical and the RCP4.5 simulations, this article evaluated the performance of the RegCM4 downscaling simulations on the air environment carrying capacity (AEC) and weak ventilation days (WVDs) in China, which are applied to measure haze pollution potential. Their changes during the middle and the end of the 21st century were also projected. The evaluations show that the RegCM4 downscaling simulations can generally capture the observed features of the AEC and WVD distributions over the period 1986–2005. The projections indicate that the annual AEC tends to decrease and the annual WVDs tend to increase over almost the whole country except central China, concurrent with greater change by the late 21st century than by the middle of the 21st century. It suggests that annual haze pollution potential would be enlarged under the RCP4.5 scenario compared to the present. For seasonal change in the four main economic zones of China, it is projected consistently that there would be a higher probability of haze pollution risk over the Beijing–Tianjin–Hebei (BTH) region and the Yangtze River Delta (YRD) region in winter and over the Pearl River Delta (PRD) region in spring and summer in the context of the warming scenario. Over Northeast China (NEC), future climate change might reduce the AEC or increase the WVDs throughout the whole year, which favours the occurrence of haze pollution and thus the haze pollution risk would be aggravated. The relative contribution of different components related to the AEC change further indicates that changes in the boundary layer depth and the wind speed play leading roles in the AEC change over the BTH and NEC regions. In addition to those two factors, the precipitation change also exerts important impacts on the AEC change over the YRD and PRD zones.

North Atlantic jet stream projections in the context of the past 1,250 years

2021 ◽  
Vol 118 (38) ◽  
pp. e2104105118
Author(s):  
Matthew B. Osman ◽  
Sloan Coats ◽  
Sarah B. Das ◽  
Joseph R. McConnell ◽  
Nathan Chellman
Keyword(s):  
21St Century ◽  
North Atlantic ◽  
Climate Model ◽  
Ice Cores ◽  
Natural Variability ◽  
Jet Stream ◽  
Early 21St Century ◽  
The North ◽  
North Atlantic Jet ◽  
Water Isotope

Reconstruction of the North Atlantic jet stream (NAJ) presents a critical, albeit largely unconstrained, paleoclimatic target. Models suggest northward migration and changing variance of the NAJ under 21st-century warming scenarios, but assessing the significance of such projections is hindered by a lack of long-term observations. Here, we incorporate insights from an ensemble of last-millennium water isotope–enabled climate model simulations and a wide array of mean annual water isotope (δ18O) and annually accumulated snowfall records from Greenland ice cores to reconstruct North Atlantic zonal-mean zonal winds back to the 8th century CE. Using this reconstruction we provide preobservational constraints on both annual mean NAJ position and intensity to show that late 20th- and early 21st-century NAJ variations were likely not unique relative to natural variability. Rather, insights from our 1,250 year reconstruction highlight the overwhelming role of natural variability in thus far masking the response of midlatitude atmospheric dynamics to anthropogenic forcing, consistent with recent large-ensemble transient modeling experiments. This masking is not projected to persist under high greenhouse gas emissions scenarios, however, with model projected annual mean NAJ position emerging as distinct from the range of reconstructed natural variability by as early as 2060 CE.

scholarly journals Evolution of Antarctic ozone in September–December predicted by CCMVal-2 model simulations for the 21st century

2013 ◽  
Vol 13 (8) ◽  
pp. 4413-4427 ◽  
Author(s):  
J. M. Siddaway ◽  
S. V. Petelina ◽  
D. J. Karoly ◽  
A. R. Klekociuk ◽  
R. J. Dargaville
Keyword(s):  
21St Century ◽  
Climate Model ◽  
Polar Vortex ◽  
Early Summer ◽  
Slow Increase ◽  
Large Variability ◽  
Model Simulations ◽  
Antarctic Ozone ◽  
Decadal Rate ◽  
The Antarctic

Abstract. Chemistry-Climate Model Validation phase 2 (CCMVal-2) model simulations are used to analyze Antarctic ozone increases in 2000–2100 during local spring and early summer, both vertically integrated and at several pressure levels in the lower stratosphere. Multi-model median trends of monthly zonal mean total ozone column (TOC), ozone volume mixing ratio (VMR), wind speed and temperature poleward of 60° S are investigated. Median values are used to account for large variability in models, and the associated uncertainty is calculated using a bootstrapping technique. According to the trend derived from the twelve CCMVal-2 models selected, Antarctic TOC will not return to a 1965 baseline, an average of 1960–1969 values, by the end of the 21st century in September–November, but will return in ~2080 in December. The speed of December ozone depletion before 2000 was slower compared to spring months, and thus the decadal rate of December TOC increase after 2000 is also slower. Projected trends in December ozone VMR at 20–100 hPa show a much slower rate of ozone recovery, particularly at 50–70 hPa, than for spring months. Trends in temperature and winds at 20–150 hPa are also analyzed in order to attribute the projected slow increase of December ozone and to investigate future changes in the Antarctic atmosphere in general, including some aspects of the polar vortex breakup.

scholarly journals Extreme Rainfall Projections for Malaysia at the End of 21st Century Using the High Resolution Non-Hydrostatic Regional Climate Model (NHRCM)

SOLA ◽  
2020 ◽  
Vol 16 (0) ◽  
pp. 132-139
Author(s):  
Sheau Tieh Ngai ◽  
Hidetaka Sasaki ◽  
Akihiko Murata ◽  
Masaya Nosaka ◽  
Jing Xiang Chung ◽  
...  
Keyword(s):  
High Resolution ◽  
Regional Climate Model ◽  
21St Century ◽  
Climate Model ◽  
Regional Climate ◽  
Extreme Rainfall

scholarly journals Technical-Economic Analysis of Grapple Saw

2020 ◽  
Vol 41 (2) ◽  
pp. 219-229 ◽  
Author(s):  
Ricardo Hideaki Miyajima ◽  
Paulo Torres Fenner ◽  
Gislaine Cristina Batistela ◽  
Danilo Simões
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Monte Carlo Method ◽  
Probability Distributions ◽  
Simulation Method ◽  
Forest Harvesting ◽  
Production Costs ◽  
Wood Harvesting ◽  
Food And Agriculture ◽  
The Monte Carlo Method

The processing of Eucalyptus logs is a stage that follows the full tree system in mechanized forest harvesting, commonly performed by grapple saw. Therefore, this activity presents some associated uncertainties, especially regarding technical and silvicultural factors that can affect productivity and production costs. To get around this problem, Monte Carlo simulation can be applied, or rather a technique that allows to measure the probabilities of values from factors that are under conditions of uncertainties, to which probability distributions are attributed. The objective of this study was to apply the Monte Carlo method for determining the probabilistic technical-economical coefficients of log processing using two different grapple saw models. Field data were obtained from an area of forest planted with Eucalyptus, located in the State of São Paulo, Brazil. For the technical analysis, the time study protocol was applied by the method of continuous reading of the operational cycle elements, which resulted in production. As for the estimated cost of programmed hour, the applied methods were recommended by the Food and Agriculture Organization of the United Nations. The incorporation of the uncertainties was carried out by applying the Monte Carlo simulation method, by which 100,000 random values were generated. The results showed that the crane empty movement is the operational element that most impacts the total time for processing the logs; the variables that most influence the productivity are specific to each grapple saw model; the difference of USD 0.04 m3 in production costs was observed between processors with gripping area of 0.58 m2 and 0.85 m2. The Monte Carlo method proved to be an applicable tool for mechanized wood harvesting for presenting a range of probability of occurrences for the operational elements and for the production cost.

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