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Moody, J. L., J. W. Munger, A. H. Goldstein, D. J. Jacob e S. C. Wofsy. "Harvard Forest regional-scale air mass composition by Patterns in Atmospheric Transport History (PATH)". Journal of Geophysical Research: Atmospheres 103, n. D11 (1 giugno 1998): 13181–94. http://dx.doi.org/10.1029/98jd00526.
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Castro, Mark S., Jerry M. Melillo, Paul A. Steudler e Jon W. Chapman. "Soil moisture as a predictor of methane uptake by temperate forest soils". Canadian Journal of Forest Research 24, n. 9 (1 settembre 1994): 1805–10. http://dx.doi.org/10.1139/x94-233.
Testo completoAbstract (sommario):
We conducted soil moisture manipulation experiments in a red pine (Pinusresinosa Ait.) plantation at the Harvard Forest (Petersham, Mass.) in August 1992 and May 1993. To manipulate soil moisture, we added 10 cm of groundwater to 1-m2 plots and allowed the soils to dry down to their pretreatment moisture contents. We measured methane (CH4) flux, soil moisture, and temperature prior to and after the water addition. Soils in both the control and watered plots were usually sinks for atmospheric CH4. Average consumption rates by control soils ranged from 0.12 to 0.17 mg CH4-C•m−2•h−1. Methane consumption rates by watered soils ranged from 0 to 0.12 mg CH4-C•m−2•h−1 and were inversely related to the moisture content of the upper 10 cm of mineral soil. Linear regression between soil moisture and CH4 consumption explained 78% of the variability (CH4 consumption = 0.001 75 (percent water filled pore space)–0.1957). Using this empirical relationship, we predicted CH4 consumption by soils at three other locations in the Harvard Forest, which agreed closely (r2 = 0.7574) with rates measured in the spring, summer, and fall of 1988–1992. Results from our study suggest that soil moisture is a good predictor of methane uptake by these forest soils and may be used to predict how future changes in soil moisture resulting from alterations in regional precipitation patterns will affect the strength of this terrestrial CH4 sink.
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HARRINGTON, JOEL F. "THE FOREST FOR THE TREES: SOCIETY AND THE HOUSEHOLD IN EARLY MODERN EUROPE". Historical Journal 41, n. 4 (dicembre 1998): 1161–72. http://dx.doi.org/10.1017/s0018246x98008218.
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Gender relations in German history: power, agency, and experience from the sixteenth to the twentieth century. Edited by Lynn Abrams and Elizabeth Harvey. London: UCL, 1996. Pp. x+262. ISBN 1-85728-485-2. £12.95.Adultery and divorce in Calvin's Geneva. By Robert M. Kingdon. Cambridge, Mass., and London: Harvard UP, 1995. Pp. ix+214. ISBN 0-674-00520-1 (hb). £18.50.Housecraft and statecraft: domestic service in Renaissance Venice, 1400–1600. By Dennis Romano. Baltimore: Johns Hopkins University Press, 1996. Pp. xxvi+333. ISBN 0-8018-5288-9. £37.00.The European nobility, 1400–1800. By Jonathan Dewald. New approaches to European history, ix. Cambridge: Cambridge University Press, 1996. Pp. xvii+209. ISBN 0-521-42528-x (pb). £12.95.Garden and grove: the Italian Renaissance garden in the English imagination, 1600–1750. By John Dixon Hunt. Philadelphia: University of Pennsylvania, 1996. Pp. xix+268. ISBN 0-8122-1604-0 (pb). £23.50.Like an ancient woodsman or a guide through the Amazonian jungle, the ideal historian possesses at least two kinds of expertise: enough familiarity with the general terrain to plan successful expeditions and enough experience in the field to make inevitable adjustments to ‘the big picture’ when underway. Of course in the real world (of both geography and history) the tasks of exploration and cartography are often bifurcated, without necessarily disastrous results. The historian who is equally skilled at both close-up description and large-scale theorizing is consequently celebrated as a rare and valued anomaly. Meanwhile, for most of us stumbling scouts, the world beyond our familiar trails remains largely one of learned lore, with connections to our own limited forays often vague at best. Unless, of course, we are fortunate enough to come across something which provides an almost magical link between the narrow and the wide, the micro and the macro.
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Bartlett, Megan K., Scott V. Ollinger, David Y. Hollinger, Haley F. Wicklein e Andrew D. Richardson. "Canopy-scale relationships between foliar nitrogen and albedo are not observed in leaf reflectance and transmittance within temperate deciduous tree species". Botany 89, n. 7 (luglio 2011): 491–97. http://dx.doi.org/10.1139/b11-037.
Testo completoAbstract (sommario):
Strong positive correlations between the maximum rate of canopy photosynthesis, canopy-averaged foliar nitrogen concentration, and canopy albedo have been shown in previous studies. While leaf-level relationships between photosynthetic capacity and foliar nitrogen are well documented, it is not clear whether leaf-level relationships between solar-weighted reflectance and nitrogen underlie the canopy-scale patterns. Using an integrating sphere, we measured the reflectance and transmittance (350–2500 nm) of both individual leaves and multileaf stacks. Samples were collected from 12 broadleaf species at the Harvard Forest in central Massachusetts, USA. Across all species, foliar nitrogen (both mass-based nitrogen concentration and area-based nitrogen content) and leaf mass / area ratio were negatively, rather than positively, correlated with solar-weighted reflectance and transmittance in ultraviolet–visible and near-infrared wavelength bands (350–700 nm and 700–2500 nm, respectively). Leaf-level anatomy and biochemistry, therefore, do not appear to drive the canopy-level association between increasing foliar nitrogen content and increasing canopy albedo. This suggests that interactions between leaf optical properties and structural canopy-scale traits that correlate with nitrogen content (perhaps some combination of crown shape, leaf area index, leaf angular distribution, or other structural characteristics of the canopy), may instead underlie the previously observed relationship between nitrogen and canopy-level shortwave albedo.
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Stott, Philip. "Harvard Forest". Global Ecology and Biogeography Letters 1, n. 4 (luglio 1991): 99. http://dx.doi.org/10.2307/2997704.
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Dunn, Christopher P. "The Harvard Forest History". Ecology 86, n. 5 (maggio 2005): 1366–67. http://dx.doi.org/10.1890/0012-9658(2005)086[1366:thfh]2.0.co;2.
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Prudham, W. Scott. "Lloyd C. Irland. The Northeast’s Changing Forest. Cambridge, Mass.: Harvard University Press, 1999. xxiv + 401 pp. ISBN 0-674-62680-X, $50.00. - Richard A. Rajala. Clearcutting the Pacific Rain Forest: Production, Science, and Regulation. Vancouver: University of British Columbia Press, 1998. xxiii + 286 pp. ISBN 0-7748-0590-0, $75.00 (cloth); 0-7748-0591-9, $27.95 (paper)." Enterprise & Society 2, n. 1 (marzo 2001): 184–87. http://dx.doi.org/10.1017/s1467222700003323.
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Allen, A. "Soil Science and Survey at Harvard Forest". Soil Horizons 36, n. 4 (1995): 133. http://dx.doi.org/10.2136/sh1995.4.0133.
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Staebler, Ralf M., e David R. Fitzjarrald. "Measuring Canopy Structure and the Kinematics of Subcanopy Flows in Two Forests". Journal of Applied Meteorology 44, n. 8 (1 agosto 2005): 1161–79. http://dx.doi.org/10.1175/jam2265.1.
Testo completoAbstract (sommario):
Abstract A better understanding of forest subcanopy flows is needed to evaluate their role in the horizontal movement of scalars, particularly in complex terrain. This paper describes detailed measurements of the canopy structure and its variability in both the horizontal and vertical directions at a deciduous forest in complex terrain (the Harvard Forest, Petersham, Massachusetts). The effects of the trunks and subcanopy shrubs on the flow field at each of six subcanopy array locations are quantified. The dynamics of the subcanopy flow are examined with pragmatic methods that can be implemented on a small scale with limited resources to estimate the stress divergence, buoyancy, and pressure gradient forces that drive the flow. The subcanopy flow at the Harvard Forest was driven by mechanisms other than vertical stress divergence 75% of the time. Nocturnal flows were driven predominantly by the negative buoyancy of a relatively cool layer near the forest floor. The direction of the resulting drainage flows followed the azimuth of the longest forest-floor slope. Similar results were found at a much flatter site at Borden, Ontario, Canada. There was no clear evidence of flow reversals in the subcanopy in the lee of ridges or hills at the Harvard Forest even in high wind conditions, contrary to some model predictions.
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Berliner, Ruhama, e John G. Torrey. "Studies on mycorrhizal associations in Harvard Forest, Massachusetts". Canadian Journal of Botany 67, n. 8 (1 agosto 1989): 2245–51. http://dx.doi.org/10.1139/b89-287.
Testo completoAbstract (sommario):
An estimate was made of the abundance of different types of mycorrhizal associations in two plant communities of conifers and hardwoods in the Harvard Forest. Lists of plant species, the coverage of their foliage in the canopy and understorey layers, and the types of mycorrhizal associations for 45 species common in these communities are presented. Of the species examined, 91 % were mycorrhizal, representing most of the known major types, viz. ectomycorrhiza, vesicular–arbuscular mycorrhiza (VAM), ericoid, and monotropoid mycorrhiza. Of the 45 species studied, 22% of the species showed ectomycorrhizal, and 71 % VAM associations. A direct spore count was a more reliable method than the most probable number method for determining VAM occurrence in the soil. Spore numbers ranged from 4.4 to 11.8 spores/g oven-dried soil. In conifer stands, ectomycorrhizae were most common, although VAM were also observed in the conifer species. In hardwood stands, VAM were more frequent than in conifer stands, but mycorrhizae were heterogeneous and included a good proportion of the ericoid type. Ectomycorrhizae were more common in communities of low diversity; VAM occurred more frequently in communities of high plant species diversity.
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Orwig, D. A., P. Boucher, I. Paynter, E. Saenz, Z. Li e C. Schaaf. "The potential to characterize ecological data with terrestrial laser scanning in Harvard Forest, MA". Interface Focus 8, n. 2 (16 febbraio 2018): 20170044. http://dx.doi.org/10.1098/rsfs.2017.0044.
Testo completoAbstract (sommario):
Contemporary terrestrial laser scanning (TLS) is being used widely in forest ecology applications to examine ecosystem properties at increasing spatial and temporal scales. Harvard Forest (HF) in Petersham, MA, USA, is a long-term ecological research (LTER) site, a National Ecological Observatory Network (NEON) location and contains a 35 ha plot which is part of Smithsonian Institution's Forest Global Earth Observatory (ForestGEO). The combination of long-term field plots, eddy flux towers and the detailed past historical records has made HF very appealing for a variety of remote sensing studies. Terrestrial laser scanners, including three pioneering research instruments: the Echidna Validation Instrument, the Dual-Wavelength Echidna Lidar and the Compact Biomass Lidar, have already been used both independently and in conjunction with airborne laser scanning data and forest census data to characterize forest dynamics. TLS approaches include three-dimensional reconstructions of a plot over time, establishing the impact of ice storm damage on forest canopy structure, and characterizing eastern hemlock ( Tsuga canadensis ) canopy health affected by an invasive insect, the hemlock woolly adelgid ( Adelges tsugae ). Efforts such as those deployed at HF are demonstrating the power of TLS as a tool for monitoring ecological dynamics, identifying emerging forest health issues, measuring forest biomass and capturing ecological data relevant to other disciplines. This paper highlights various aspects of the ForestGEO plot that are important to current TLS work, the potential for exchange between forest ecology and TLS, and emphasizes the strength of combining TLS data with long-term ecological field data to create emerging opportunities for scientific study.
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Miller, C. "Book Review: Recent Books on Forest History". Journal of Forestry 98, n. 11 (1 novembre 2000): 55–56. http://dx.doi.org/10.1093/jof/98.11.55.
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Abstract Reviews of Walt Perry: An Early-Day Forest Ranger in New Mexico and Oregon, edited by Les Joslin; “I'll Never Fight Fire with My Bare Hands Again”: Recollections of the First Forest Rangers of the Inland Northwest, edited by Hal K. Rothman; Co-Operative Dreams: A history of the Kaweah Colony by Jay O'Connell; and New England Forests through Time: Insights from the Harvard Forest Dioramas.
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Berliner, Ruhama, e John G. Torrey. "Erratum: Studies on mycorrhizal associations in Harvard Forest, Massachusetts". Canadian Journal of Botany 68, n. 1 (1 gennaio 1990): 223. http://dx.doi.org/10.1139/b90-030.
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Eshel, Gidon, Archana Dayalu, Steven C. Wofsy, J. William Munger e Eli Tziperman. "Listening to the Forest: An Artificial Neural Network‐Based Model of Carbon Uptake at Harvard Forest". Journal of Geophysical Research: Biogeosciences 124, n. 3 (marzo 2019): 461–78. http://dx.doi.org/10.1029/2018jg004791.
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Podrezov, J. V., e V. V. Abelmazov. "MODERN FEATURES OF MASS FOREST FIRES". Проблемы безопасности и чрезвычайных ситуаций, n. 4 (2022): 88–93. http://dx.doi.org/10.36535/0869-4176-2022-04-10.
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Abelmazov, V. V. "MODERN FEATURES OF MASS FOREST FIRES". Проблемы безопасности и чрезвычайных ситуаций, n. 4 (2022): 85–88. http://dx.doi.org/10.36535/0869-4176-2022-04-9.
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Min, Qilong, e Bing Lin. "Remote sensing of evapotranspiration and carbon uptake at Harvard Forest". Remote Sensing of Environment 100, n. 3 (febbraio 2006): 379–87. http://dx.doi.org/10.1016/j.rse.2005.10.020.
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Bowden, Richard D., Eric Davidson, Kathleen Savage, Chris Arabia e Paul Steudler. "Chronic nitrogen additions reduce total soil respiration and microbial respiration in temperate forest soils at the Harvard Forest". Forest Ecology and Management 196, n. 1 (luglio 2004): 43–56. http://dx.doi.org/10.1016/j.foreco.2004.03.011.
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Isaev, A. V., e Yu P. Demakov. "Forest Litter Features in Floodplain Forest of the “Bolshaya Kokshaga” Reserve". Лесоведение, n. 1 (1 gennaio 2023): 66–76. http://dx.doi.org/10.31857/s0024114823010072.
Testo completoAbstract (sommario):
The studies, carried out in the floodplain ecotopes of the Bolshaya Kokshaga reserve (Russia, the Republic of Mari El) are relevant due to the need to understand the patterns of formation of the forest litter properties, which are a sensitive integral indicator of the biogeocenoses conditions. The work has been carried out on 20 test plots located in different parts of the floodplain in areas with a point bar type of river bed evolution, and, in addition to the main physicochemical parameters, the weight of the litter, its fractional composition and seasonal dynamics, as well as carbon reserves in it, were estimated. It was established that the weight of the litter on the studies sites decreased during the growing season from 20 to 33% of its value at the end of May. The main loss of its mass was observed in the first half of summer. The variability of the litter’s physicochemical parameters, especially its acidity, the degree of base saturation, the exchangeable calcium content, as well as the content of mobile phosphorus and potassium compounds, was found to be tied mainly to the features of the ecotopes, and their seasonal changes turned out to be statistically insignificant. It was determined that the greatest differences between the ecotopes were in the litter mass and the carbon stock in it. The mobile potassium and exchangeable calcium content were the highest in the litter of biotopes from the central part of the floodplain, and the content of ash and mobile phosphorus was the highest in the near-river zone. The ecotopes differed least of all in terms of the litter acidity and the degree of base saturation. It was shown that the carbon mass and stock in the litter of floodplain forests were significantly lower than in watershed stands, which was explained by its partial removal during floods, having the strongest effect in near-river ecotopes. The litter from the floodplain ecotopes, compared to the watershed ecotopes, also had significantly lower values of acidity, ash content, the sum of exchangeable bases, and the mobile potassium content. They surpassed the litter of lichen and mossy pine forests only in the mobile phosphorus content.
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Archibald, S. Bruce, William H. Bossert, David R. Greenwood e Brian D. Farrell. "Seasonality, the latitudinal gradient of diversity, and Eocene insects". Paleobiology 36, n. 3 (2010): 374–98. http://dx.doi.org/10.1666/09021.1.
Testo completoAbstract (sommario):
In the modern world, biotic diversity is typically higher in low-latitude tropical regions where there is abundant insolation (light and heat) and low thermal seasonality. Because these factors broadly covary with latitude, separating their possible effects on species diversity is difficult. The Eocene was a much more equable world, however, with low temperature seasonality extending into lower-insolation higher, cooler latitudes, allowing us to test these factors by comparing insect species diversity in (1) modern, temperate, low-insolation, highly seasonal Harvard Forest, Massachusetts, U.S.A., 42°29'N; (2) modern, tropical, high-insolation, low-seasonality La Selva, Costa Rica, 10°26'N, and; (3) Eocene, temperate, low-insolation, yet low-seasonality McAbee, British Columbia, Canada, above 50°N paleolatitude. We found insect diversity at McAbee to be more similar to La Selva than to Harvard Forest, with high species richness of most groups and decreased diversity of ichneumon wasps, indicating that seasonality is key to the latitudinal diversity gradient. Further, midlatitude Eocene woody dicot diversities at McAbee, Republic (Washington, U.S.A.), and Laguna del Hunco (Argentina) are also high, similar to modern tropical samples, higher than at the modern midlatitude Harvard Forest. Modern correlations between latitude, species diversity, and seasonal climates were established some time after the Eocene.
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Гниненко, Ю. И. "Rare forest pests". Лесохозяйственная информация, n. 3 (17 settembre 2021): 70–82. http://dx.doi.org/10.24419/lhi.2304-3083.2021.3.06.
Testo completoAbstract (sommario):
Рассмотрены примеры развития очагов массового размножения вредителей леса, которые на большей части своего ареала являются редкими. Некоторые из них внесены в красные книги России или ее регионов. Причины, приводящие к возникновению очагов таких насекомых, как и закономерности развития вспышек их численности, не известны. Некоторые из рассмотренных видов насекомых формировали очаги на небольших площадях один раз или в течение нескольких десятилетий, а другие фитофаги реализовывали вспышки массового размножения на обширных территориях и наносили существенные повреждения кормовым лесным породам. Трудности с определением видовой принадлежности редких фитофагов иногда приводят к тому, что против них проводят истребительные меры борьбы, в то время как эти насекомые занесены в красные книги. Указано, что редкое возникновение вспышек численности у некоторых видов вредителей леса на части их обширного ареала до настоящего времени научно не обосновано. Это не позволяет принимать взвешенные решения об организации мер защиты лесов от редких вредителей леса, так как нет мотивации для мониторинга выявления их очагов. The examples of the development of foci of mass reproduction of forest pests, which are rare in most of their range, are considered. Some of them are included in the red books of Russia or its regions. The reasons leading to the emergence of foci of such insects, as well as the patterns of development of outbreaks of their numbers, are not known. Some of the considered species of insects formed foci in small areas (once or over several decades), while other phytophages realized outbreaks of mass reproduction in vast territories and caused significant damage to forage forest species. Difficulties in determining the species of rare phytophages sometimes lead to the fact that that extermination measures are being carried out against them, while these insects are listed in the red books. It is indicated that the rare occurrence of outbreaks in some species of forest pests on a part of their vast range has not been scientifically substantiated to date. This does not allow making informed decisions on the organization of measures to protect forests from rare forest pests, since there is no motivation for organizing monitoring of identifying their foci.
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Hayati, Muktasam, R. H. Sayuti e N. Valentino. "Perspective in community forest management in Central Lombok Regency". IOP Conference Series: Earth and Environmental Science 1107, n. 1 (1 dicembre 2022): 012117. http://dx.doi.org/10.1088/1755-1315/1107/1/012117.
Testo completoAbstract (sommario):
Abstract The gender perspective in community forest management in Central Lombok Regency is focused on analyzing gender equality in domestic and productive activities, particularly access and control of forest resources. This research is conducted by using Framework Harvard Analysis through interviews with respondents, in-depth interviews and focus group discussions with certain informants. The unit of this research’s analysis is women whose household has the right to manage community forest. This study shows that there is a gender equality bias which is indicated by the low participation of women in controlling forest resources (planning, regulation, evaluation) due to the stereotypical view of gender roles in decision making which is dominated by men. However, the high participation of women is more involved in terms of access to forest resources (implementation, crop productivity, utilization) to improve household food security. Forest farmer households with a high level of gender equality through the active involvement of women in controlling forest resources will improve social and economic adaptation strategies with a high level of diversity.
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Yin, Xiwei, James A. Perry e Robert K. Dixon. "Influence of canopy removal on oak forest floor decomposition". Canadian Journal of Forest Research 19, n. 2 (1 febbraio 1989): 204–14. http://dx.doi.org/10.1139/x89-029.
Testo completoAbstract (sommario):
We compared leaf and forest floor mass loss rates over 2 years on undisturbed (NC), shelterwood-cut (SC0), and clear-cut (CC) sites in a Quercus forest at the Hardie's Creek Forest, Wisconsin, U.S.A. Litterbag techniques and a budgetary approach based on forest floor surveys and litterfall estimations were used. SC0 and NC variables did not differ until final harvest on SC0 (creating SC1). Over a 6-month period, 19% of initial cellulose (filter disk) mass was lost from litterbags placed on SC1 compared with 71% on NC. Leaf mass loss from litterbags was consistently slower on CC than on NC. Rates of mass loss to the upper (01) and lower (02) forest floor horizons in 1985 and total forest floor mass loss rate in both years did not differ among sites; mass loss rate for 01 was lower on CC than on NC, but higher for 02 in 1986. Differences in mass loss rates between CC and NC were attributed to changes in environment (ambient temperature and water content of the soil and forest floor) that were induced by clear-cutting. We suggest that the effects of canopy removal on mass loss from leaf litter appear to vary with regional climatic variables, while the effects on overall forest floor mass loss rate may be buffered by compensation among various forest floor horizons in most areas.
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Currie, William S., John D. Aber e Charles T. Driscoll. "Leaching of nutrient cations from the forest floor: effects of nitrogen saturation in two long-term manipulations". Canadian Journal of Forest Research 29, n. 5 (1 maggio 1999): 609–20. http://dx.doi.org/10.1139/x99-033.
Testo completoAbstract (sommario):
Nitrogen saturation results in greater mobility of nitrate, which in turn is often correlated with concentrations of nutrient cations in soil solution and streamwater. At the Harvard Forest, U.S.A., under long-term NH4NO3 inputs, a Pinus resinosa Ait. forest has exhibited signs of N saturation more rapidly than a mixed-Quercus forest. We test the hypothesis that increased nitrate leaching causes increased concentrations of nutrient cations in soil solution. Over 2 years (years 6 and 7 of treatment) we measured SO42-, NO3-, Cl-, Ca2+, K+, Mg2+, Na+, H+, and NH4+ in throughfall solution and in forest-floor (Oa) leachate. Concentrations of NO3- in forest-floor leachate increased with rates of N amendment and correlated positively with cation concentrations, with stronger overall correlations in the pine forest: r2 values were 0.51 (pine forest) and 0.39 (oak forest) for Ca2+, 0.45 (pine) and 0.16 (oak) for K+, and 0.62 (pine) and 0.50 (oak) for Mg2+. In summer and fall, the oak forest showed some negative relationships between nutrient cation leaching and rate of N amendment. These contrasts showed retention of cations and N to occur together in an N-limited system, whereas increased nitrate mobility occurred with increased cation losses in an N-saturated system.
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Lang, Gerald E. "Forest turnover and the dynamics of bole wood litter in subalpine balsam fir forest". Canadian Journal of Forest Research 15, n. 1 (1 febbraio 1985): 262–68. http://dx.doi.org/10.1139/x85-044.
Testo completoAbstract (sommario):
A chronosequence of three stands of balsam fir was sampled in 1974 and 1982; during these 8 years, recruitment was absent so mortality alone accounted for an 18–30% decrease in live tree density. In a mature 78-year-old stand, the mass of bole wood on the forest floor was 1.4 kg•m−2 compared with an estimated aboveground live and dead bole biomass of 17.2 kg•m−2. During 5 years of repetitive sampling, annual bole input to the forest floor was episodic and variable in time and space, ranging from 3 to 365 g•m−2•year−1. A mass balance model was used to characterize the changes in wood litter on the forest floor. If most of the live trees die within a short period of time, bole input would occur in a pulse event and cause a peak in wood litter mass, which would then decline over time (and with stand maturation) as decomposition prevails. The assumption of steady-state conditions for wood litter is not valid; rather the mass of wood litter will wax and wane through time. Over a landscape, spatial patterns in the abundance of wood litter reflect a stand's history; old mature stands would have little wood litter while young regenerating stands would have large amounts. A maximum value for wood litter would be found in a stand located immediately behind a fir wave. Natural disturbances from wind and avalanches lead to contrasting patterns with high and low wood litter values, respectively. About 41% of forest turnover in the balsam fir zone is initiated from natural disturbance and fir waves.
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NISHIMURA, TAKASHI B., e EIZI SUZUKI. "Allometric differentiation among tropical tree seedlings in heath and peat-swamp forests". Journal of Tropical Ecology 17, n. 5 (settembre 2001): 667–81. http://dx.doi.org/10.1017/s0266467401001493.
Testo completoAbstract (sommario):
Above- and below-ground morphology of seedlings (up to 98 cm in height) were compared by allometric analyses in tropical heath forest and peat-swamp forest in Central Kalimantan. Thirteen abundant species were selected, including two species found in both forests. In above-ground morphology, heath forest seedlings invested more in leaf mass, while peat-swamp forest seedlings invested more in stem mass, stem height, crown area and leaf area. In below-ground morphology, heath forest seedlings invested more in root mass and depth, while peat-swamp forest seedlings invested more in lateral development of the root system. Both specific leaf area and area per leaf of heath forest seedlings were lower than those of peat-swamp forest seedlings. This differentiation in seedling morphology between forest types was evident as a plastic response in the two shared species. Heath forest seedlings on coarse-textured bleached sand with low water retention suffer occasional drought whereas peat-swamp forest seedlings on waterlogged peat rarely experience drought. We concluded that seasonal water limitation brought about the convergence in seedling morphology within heath forest because average understorey irradiances and soil nutrient concentration were assumed to be similarly low in both forests.
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Mogotsi, Immaculate, Selma Lendelvo, Margaret Angula e Jesaya Nakanyala. "Forest Resource Management and Utilisation through a Gendered Lens in Namibia". Environment and Natural Resources Research 6, n. 4 (11 novembre 2016): 79. http://dx.doi.org/10.5539/enrr.v6n4p79.
Testo completoAbstract (sommario):
The shift in forestry policy towards resource management and access rights from state control to local community control has been a welcome step towards sustainable forest management in Namibia. The policy acknowledges the direct dependence on natural environmental resources by the proportional majority of the population that live in the rural areas of Namibia. This study was aimed at performing gender analysis by identifying relationships of various groups to natural resources. The study further assessed the influence these relationships have on control, access and use of forest resources, as well as on natural resource management and the implications thereof on various forest management efforts in the country. Data were collected from seven community forest institutions in Namibia and analysed using the Harvard Gender Analytical Framework. The findings show a gendered differentiated knowledge, control and access to forest resources and unequal participation in leadership and governance. Furthermore, the results suggest that unequal power relations among minority and vulnerable groups affect access to and control of forest resources. This study proposes participation of both men and women in the management, protection, access and utilisation of forest resources, as this will contribute to sustainable forest management and economic development of all members of society.
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Waggoner, P. E. "Using the Forest Identity to grasp and comprehend the swelling mass of forest statistics". International Forestry Review 10, n. 4 (dicembre 2008): 689–94. http://dx.doi.org/10.1505/ifor.10.4.689.
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Sprugel, Douglas G. "Changes in biomass components through stand development in wave-regenerated balsam fir forests". Canadian Journal of Forest Research 15, n. 1 (1 febbraio 1985): 269–78. http://dx.doi.org/10.1139/x85-045.
Testo completoAbstract (sommario):
Available data on the wave-regenerated Abiesbalsamea forests of the northeastern United States are synthesized into a model (BALSAM) which predicts changes in total and component biomass through the disturbance–regeneration cycle. Measured decay rates seem to imply a higher mean forest floor mass than is actually observed, so several alterations were made in the initial model to make it predict forest floor mass correctly. With or without these changes, forest floor mass decreases for about 12 years after disturbance, largely owing to low levels of litterfall in the early stages of stand development. Because changes in living biomass and dead bole mass through the disturbance cycle roughly cancel each other out, net ecosystem productivity closely parallels these litterfall-driven changes in the forest floor. Throughout the disturbance–regeneration cycle, the forest floor is derived primarily from woody tissue and its decay products, with foliage-derived material making up less than 25% of the total forest floor mass.
30
Ma, M., D. Wang, H. Du, T. Sun, Z. Zhao, Y. Wang e S. Wei. "Mercury dynamics and mass balance in a subtropical forest, southwestern China". Atmospheric Chemistry and Physics Discussions 15, n. 24 (21 dicembre 2015): 35857–80. http://dx.doi.org/10.5194/acpd-15-35857-2015.
Testo completoAbstract (sommario):
Abstract. The mid-subtropical forest area in southwest China was affected by anthropogenic mercury (Hg) emissions over the past three decades. We quantified mercury dynamics on the forest field and measured fluxes and pools of Hg in litterfall, throughfall, stream water and forest soil in an evergreen broad-leaf forest field in southwestern China. Total Hg (THg) input by the throughfall and litterfall were assessed at 32.2 and 42.9 μg m−2 yr−1, respectively, which were obviously higher than those formerly observed from other forest fields in the background of North America and Europe. Hg fluxes across the soil/air interface (18.6 μg m−2 yr−1) and runoff/stream flow (7.2 μg m−2 yr−1) were regarded as the dominant ways for THg export from the forest field. The forest field hosts an enormous amount of atmospheric Hg, and its reserves were estimated to 25 341 μg m2. The ratio of output to input Hg fluxes (0.34) is higher comparing with other study sites. The higher output/input ratio may represent an important ecological risk for the downstream aquatic ecosystems, even if~the forest field could be an effective sink of Hg.
31
Ma, Ming, Dingyong Wang, Hongxia Du, Tao Sun, Zheng Zhao, Yongmin Wang e Shiqiang Wei. "Mercury dynamics and mass balance in a subtropical forest, southwestern China". Atmospheric Chemistry and Physics 16, n. 7 (13 aprile 2016): 4529–37. http://dx.doi.org/10.5194/acp-16-4529-2016.
Testo completoAbstract (sommario):
Abstract. The mid-subtropical forest area in southwest China was affected by anthropogenic mercury (Hg) emissions over the past 3 decades. We quantified mercury dynamics on the forest field and measured fluxes and pools of Hg in litterfall, throughfall, stream water and forest soil in an evergreen broadleaved forest field in southwestern China. Total Hg (THg) input by the throughfall and litterfall was assessed at 32.2 and 42.9 µg m−2 yr−1, respectively, which was remarkably higher than those observed from other forest fields in the background of North America and Europe. Hg fluxes across the soil–air interface (18.6 mg m−2 yr−1) and runoff and/or stream flow (7.2 µg m−2 yr−1) were regarded as the dominant ways for THg export from the forest field. The forest field hosts an enormous amount of atmospheric Hg, and its reserves is estimated to be 25 341 µg m2. The ratio of output to input Hg fluxes (0.34) is higher compared with other study sites. The higher output / input ratio may represent an important ecological risk for the downstream aquatic ecosystems, even if the forest field could be an effective sink of Hg.
32
Fang, Yiran, Xiaojun Zou, Zhiyang Lie e Li Xue. "Variation in Organ Biomass with Changing Climate and Forest Characteristics across Chinese Forests". Forests 9, n. 9 (29 agosto 2018): 521. http://dx.doi.org/10.3390/f9090521.
Testo completoAbstract (sommario):
Forest biomass allocation patterns are important for understanding global carbon cycling and climate change, which might change with environmental conditions and forest characteristics. However, the effects of climate and forest characteristics on biomass allocation fractions (the fraction of total forest biomass distributed in organs) remains unknown. The authors use a large Chinese biomass dataset (1081 forests encompassing 10 forest types) to analyse the responses of biomass allocation fractions to biogeography, climate, and forest characteristics. The authors found that the stem mass fraction significantly increased with age and precipitation and significantly decreased with latitude and temperature. The branch mass fraction significantly decreased with age and density, but significantly increased with temperature and latitude. The leaf mass fraction significantly decreased with age and precipitation and significantly increased with temperature. The root mass fraction significantly increased with latitude and density, and significantly decreased with precipitation. The results suggest that latitude, temperature, precipitation, stand age and density are good predictors of biomass partitioning. These findings support the hypotheses that variation in resource availability constrains organ allocation and provides biogeographically explicit relationships between biomass allocation and both environmental and forest characteristics, which might be used for assessing the impact of changing environmental and forest characteristics on forest carbon dynamics and fixation.
33
Bautista, Nahuel, Bruno D. V. Marino e J. William Munger. "Science to Commerce: A Commercial-Scale Protocol for Carbon Trading Applied to a 28-Year Record of Forest Carbon Monitoring at the Harvard Forest". Land 10, n. 2 (6 febbraio 2021): 163. http://dx.doi.org/10.3390/land10020163.
Testo completoAbstract (sommario):
Forest carbon sequestration offset protocols have been employed for more than 20 years with limited success in slowing deforestation and increasing forest carbon trading volume. Direct measurement of forest carbon flux improves quantification for trading but has not been applied to forest carbon research projects with more than 600 site installations worldwide. In this study, we apply carbon accounting methods, scaling hours to decades to 28-years of scientific CO2 eddy covariance data for the Harvard Forest (US-Ha1), located in central Massachusetts, USA and establishing commercial carbon trading protocols and applications for similar sites. We illustrate and explain transactions of high-frequency direct measurement for CO2 net ecosystem exchange (NEE, gC m−2 year−1) that track and monetize ecosystem carbon dynamics in contrast to approaches that rely on forest mensuration and growth models. NEE, based on eddy covariance methodology, quantifies loss of CO2 by ecosystem respiration accounted for as an unavoidable debit to net carbon sequestration. Retrospective analysis of the US-Ha1 NEE times series including carbon pricing, interval analysis, and ton-year exit accounting and revenue scenarios inform entrepreneur, investor, and landowner forest carbon commercialization strategies. CO2 efflux accounts for ~45% of the US-Ha1 NEE, an error of ~466% if excluded; however, the decades-old coupled human and natural system remains a financially viable net carbon sink. We introduce isoflux NEE for t13C16O2 and t12C18O16O to directly partition and quantify daytime ecosystem respiration and photosynthesis, creating new soil carbon commerce applications and derivative products in contrast to undifferentiated bulk soil carbon pool approaches. Eddy covariance NEE methods harmonize and standardize carbon commerce across diverse forest applications including, a New England, USA regional eddy covariance network, the Paris Agreement, and related climate mitigation platforms.
34
Yang, Choi e Lim. "Effects of Forest Thinning on the Long-Term Runoff Changes of Coniferous Forest Plantation". Water 11, n. 11 (3 novembre 2019): 2301. http://dx.doi.org/10.3390/w11112301.
Testo completoAbstract (sommario):
Forests and water are closely related to each other. Thus, forest management is crucial for the sustainable clean water supply. Forest thinning is one of the fundamental forest management practices, as it can change runoff by controlling the density of trees. In this study, the effect of forest thinning on long-term runoff changes was evaluated, based on the long-term rainfall-runoff data of a coniferous plantation forest catchment in Korea. From the double mass curve and Pettitt’s test, a statistically significant increase in runoff rates was identified. A simple linear regression model of the double mass curve can successfully quantify the net effect of forest thinning on the runoff increase. Furthermore, it was also confirmed that forest thinning does not significantly increase the risk of flooding. About ten years after forest thinning, crown closure rates of the coniferous plantation forest reached a level similar to the pre-thinning period, and runoff rates returned to the pre-thinning level, due to forest growth. As a result of this study, a proposed direction for Korea’s forest policy for water resource management is presented for the future.
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ABRAMS, MARC D. "FROM LAND AND LAKE AND AIR: THE ECOLOGICAL BREADTH OF HARVARD FOREST". BioScience 54, n. 10 (2004): 961. http://dx.doi.org/10.1641/0006-3568(2004)054[0961:flalaa]2.0.co;2.
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36
Parsons, Scott A., e Robert A. Congdon. "Plant litter decomposition and nutrient cycling in north Queensland tropical rain-forest communities of differing successional status". Journal of Tropical Ecology 24, n. 3 (maggio 2008): 317–27. http://dx.doi.org/10.1017/s0266467408004963.
Testo completoAbstract (sommario):
Abstract:Soil processes are essential in enabling forest regeneration in disturbed landscapes. Little is known about whether litterfall from dominating pioneer species in secondary rain forest is functionally equivalent to that of mixed rain-forest litter in terms of contribution to soil processes. This study used the litterbag technique to quantify the decomposition and nutrient dynamics of leaf litter characteristic of three wet tropical forest communities in the Paluma Range National Park, Queensland, Australia over 511 d. These were: undisturbed primary rain forest (mixed rain-forest species), selectively logged secondary rain forest (pioneer Alphitonia petriei) and tall open eucalypt forest (Eucalyptus grandis). Mass loss, total N, total P, K, Ca and Mg dynamics of the decaying leaves were determined, and different mathematical models were used to explain the mass loss data. Rainfall and temperature data were also collected from each site. The leaves of A. petriei and E. grandis both decomposed significantly slower in situ than the mixed rain-forest species (39%, 38% and 29% ash-free dry mass remaining respectively). Nitrogen and phosphorus were immobilized, with 182% N and 134% P remaining in E. grandis, 127% N and 132% P remaining in A. petriei and 168% N and 121% P remaining in the mixed rain-forest species. The initial lignin:P ratio and initial lignin:N ratio exerted significant controls on decomposition rates. The exceptionally slow decomposition of the pioneer species is likely to limit soil processes at disturbed tropical rain-forest sites in Australia.
37
Ziadé, Rouba, Chadi Abdallah e Nicolas Baghdadi. "The effect of forest fire on mass movement in Lebanese mountainous areas". International Journal of Wildland Fire 23, n. 6 (2014): 845. http://dx.doi.org/10.1071/wf13077.
Testo completoAbstract (sommario):
Mass movements are major hazards that threaten natural and human environments. In Lebanon, the occurrence of mass movements increased by almost 60% between 1956 and 2008. Forest fire has emerged as an additional hazard: it destroyed over 25% of Lebanon’s forests in a period less than 40 years. This paper investigates the potential effect of forest fire on the occurrence of mass movements in the Damour and Nahr Ibrahim watersheds of Lebanon. Mass movement and forest fire inventory maps were produced through remote sensing using aerial and satellite images. Forest fire was included as an additional factor in mass movement induction, and its effect was quantified from Landsat images through the normalised burn ratio (NBR) index. A field study was conducted to substantiate the mass movement inventory and NBR maps. Following the standardisation of the effect factors into layers using geographic information systems, the weight factor of each layer for inducing mass movements was evaluated using the modified InfoVal method, and a mass movement susceptibility map was generated. Exceeded only by changes in land cover, the NBR produced the highest weights, making forest fire burn severity the second highest factor influencing mass movement occurrence in the study areas.
38
Bhattarai, Krishna Prasad, e Tej Narayan Mandal. "Variation in litter mass and its turnover in Tarai Sal forest and Hill Sal forest of eastern Nepal". Nepalese Journal of Biosciences 6, n. 1 (1 dicembre 2016): 13–18. http://dx.doi.org/10.3126/njbs.v6i1.41787.
Testo completoAbstract (sommario):
Litter on the forest floor is an important source of nutrient cycling which helps to improve the soil fertility in forest ecosystem. Comparative study was conducted to investigate the amount of annual litter mass, seasonal variation and its turnover in Tarai Sal forest (TSF) and Hill Sal forest (HSF) of eastern Nepal. Litter mass was collected in each season from 1m × 1m quadrat placed randomly on the forest floor. The total annual litter mass in TSF (6.73 Mg ha-1) was significantly (p < 0.001) higher than in HSF (5.63Mg ha-1). The seasonal pattern of litter mass was higher in summer (9.04 Mg ha-1 and 7.44 Mg ha-1) followed by rainy (6.29 Mg ha-1 and 5.11 Mg ha-1) and winter season (4.9 Mg ha-1 and 4.35 Mg ha-1) in TSF and HSF, respectively. The turnover rate for litter mass on the forest floor was higher (79%) in TSF than HSF (70%). However, turnover time was higher in HSF than TSF. Standing state nutrient in the litter layer was higher in TSF (56.21 kg N ha-1 yr-1, 6.19 kg P ha-1 yr-1 and 17.15 kg K ha-1 yr-1) than HSF (45.16 kg N ha-1 yr-1, 4.7 kg P ha-1 yr-1 and 14.19 kg K ha-1 yr-1). The difference in litter mass between these two forests may be due to differences in micro climate, soil properties and species composition.
39
Baranovskiy, Nikolay Viktorovich, e Viktoriya Andreevna Kirienko. "Mathematical Simulation of Forest Fuel Pyrolysis and Crown Forest Fire Impact for Forest Fire Danger and Risk Assessment". Processes 10, n. 3 (27 febbraio 2022): 483. http://dx.doi.org/10.3390/pr10030483.
Testo completoAbstract (sommario):
In order to predict and assess the danger from crown forest fires, it is necessary to study the thermal degradation of different forest fuels in a high-temperature environment. In this paper, the main characteristics of pyrolysis accompanied by moisture evaporation in a foliage sample of angiosperms (birch) were investigated within conditions typical for a crown forest fire. The heat and mass transfer in the forest fuel element is described by the system of non-stationary non-linear heat conduction equations with corresponding initial and boundary conditions. The considered problem is solved within the framework of the three-dimensional statement by the finite difference method. The locally one-dimensional method was used to solve three-dimensional equations for heat conduction. The simple iteration method was applied to solve nonlinear effects caused by the forest fuel pyrolysis and moisture evaporation. The fourth kind of boundary conditions are applicable at the interface between the sub-areas. Software implementation of the mathematical model is performed in the high-level programming language Delphi in the RAD Studio software. The characteristic changes in the sample temperature field and the phase composition under high-temperature exposure from a forest fire are presented. The induction period of the thermal decomposition of dry organic matter in the sample was determined. Recommendations are made about key features of accounting for the pyrolysis and evaporation processes when predicting forest fire danger. The research results can be used in the development and improvement of systems for predicting forest fire danger and environmental consequences of the forest fires.
40
Takahashi, Masamichi. "Nutrient Storage and Stoichiometry of the Forest Floor Organic Matter in Japanese Forests". Soil Systems 5, n. 3 (29 agosto 2021): 51. http://dx.doi.org/10.3390/soilsystems5030051.
Testo completoAbstract (sommario):
Nutrient storage in the forest floor is regulated through litter decomposition and nutrient cycling. Stoichiometry of nutrients can provide characterization of the forest floor. To quantify nutrient storage in the forest floor and to determine stoichiometry among different forest types, available data on nutrients were meta-analyzed. The data on nutrients—nitrogen, phosphorus, potassium, calcium, and magnesium—were collected from published reports and original data on Japanese forests. The relationship between nutrient storage and forest floor mass was also examined. Japanese cypress and cedar plantations had small N and P storage in the forest floor with high C:N and C:P ratios, whereas subalpine conifers had large N and P storage in the forest floor with low C:N and C:P ratios; cedar plantations showed large Ca-specific storage in the forest floor. The stoichiometry of the forest floor varied between different forest types, namely C:N:P ratios were 942:19:1 for cedar and cypress plantations, 625:19:1 for broad-leaved forests, and 412:13:1 for subalpine conifers and fir plantations. N storage was closely correlated; however, P and other mineral storages were weakly correlated with the forest floor mass. Nutrient storage and stoichiometry can provide a better perspective for the management of forest ecosystem.
41
de Sousa-Neto, Eráclito Rodrigues, Sílvia Rafaela Machado Lins, Susian Christian Martins, Marisa de Cássia Piccolo, Maurício Lamano Ferreira, Plínio Barbosa de Camargo, Janaina Braga do Carmo, Edmar Antonio Mazzi, Benjamin Z. Houlton e Luiz Antonio Martinelli. "Litterfall mass and nutrient fluxes over an altitudinal gradient in the coastal Atlantic Forest, Brazil". Journal of Tropical Ecology 33, n. 4 (luglio 2017): 261–69. http://dx.doi.org/10.1017/s0266467417000207.
Testo completoAbstract (sommario):
Abstract:Litterfall is one of the most important pathways through which nutrients are recycled in the terrestrial biosphere. In tropical soils, which are generally low in essential nutrients such as phosphorus and cations, the flux of nutrients through litterfall is particularly important to sustaining CO2-uptake capacity; however, questions remain over the role of altitude in altering litter nutrient cycling rates among tropical forest ecosystems. Here we examine litterfall, carbon (C), nitrogen (N) and phosphorus (P) fluxes through litterfall over an altitudinal gradient in the coastal Atlantic Forest located on the northern coast of the State of São Paulo, Brazil. Litterfall was collected twice a month for 1 y (April 2007–March 2008) using 30 litter traps placed in four different forest types arrayed by altitude – coastal forest (sea level), lowland forest (50–200 m asl), submontane forest (300–500 m asl) and montane forest (1000 m asl). Litterfall mass-fluxes decreased with increasing altitude, from ~9 Mg ha−1 in lowland forests to 7 Mg ha−1 in higher-altitude ecosystems. Contribution of reproductive organs to litterfall was significantly greater in lower than in higher altitudes. Litterfall N and P fluxes were higher in the lowland forest vs. other forest types, pointing to strong altitudinal controls over nutrient cycling. Furthermore, nitrogen-use efficiency (NUE) was lower and litter δ15N was higher in the lowland site providing additional evidence for lack of N constraints to productivity in lowland of the south-eastern Atlantic Forest.
42
Blaj, Robert. "Forest, Hunting Grounds and Hunting Lodges". Annals ”Valahia” University of Targoviste - Agriculture 12, n. 2 (1 ottobre 2018): 43–47. http://dx.doi.org/10.2478/agr-2018-0016.
Testo completo
43
Nepal, Prakash, Craig M. T. Johnston e Indroneil Ganguly. "Effects on Global Forests and Wood Product Markets of Increased Demand for Mass Timber". Sustainability 13, n. 24 (17 dicembre 2021): 13943. http://dx.doi.org/10.3390/su132413943.
Testo completoAbstract (sommario):
This study evaluated the effects on forest resources and forest product markets of three contrasting mass timber demand scenarios (Conservative, Optimistic, and Extreme), up to 2060, in twelve selected countries in Asia, Europe, North America, and South America. Analyses were carried out by utilizing the FOrest Resource Outlook Model, a partial market equilibrium model of the global forest sector. The findings suggest increases in global softwood lumber production of 8, 23, and 53 million m3 per year by 2060, under the Conservative, Optimistic, and Extreme scenarios, respectively, leading to world price increases of 2%, 7%, and 23%, respectively. This projected price increase is relative to the projected price in the reference scenario, altering prices, production, consumption, trade of forest products, timber harvest, forest growth, and forest stock in individual countries. An increase in softwood lumber prices due to increased mass timber demand would lead to the reduced consumption of softwood lumber for traditional end-use (e.g., light-frame construction), suggesting a likely strong market competition for softwood lumber between the mass timber and traditional construction industries. In contrast, the projected effect on global forest stock was relatively small based on the relatively fast projected biomass growth in stands assumed to be regenerated after harvest.
44
Krause, Helmut. "Forest floor mass and nutrients in two chronosequences of plantations: Jack pine vs. black spruce". Canadian Journal of Soil Science 78, n. 1 (1 febbraio 1998): 77–83. http://dx.doi.org/10.4141/s97-029.
Testo completoAbstract (sommario):
The purpose of this study was to determine whether change of forest cover had an effect on the development of the organic surface horizons, particularly on those variables that influence nutrient cycling and forest productivity. Jack pine (Pinus banksiana Lamb.) and black spruce (Picea mariana [Mill.] B.S.P.) plantations were selected from among the youngest to oldest (2–16 yr) within a 100 km2 area in southeastern New Brunswick. Natural forests were also included as benchmark sites. The forest floor and tree foliage was sampled and trees measured on 0.05-ha plots. The forest floor samples were used to determine organic mass, nutrient contents and pH. In pine plantations, organic matter accumulated rapidly during the period of exponential tree growth, but leveled off at about 45 Mg ha–1. This was within the range of benchmark sites with mixed conifer-hardwood cover. In spruce plantations, the forest floor mass ranged upward to 77 Mg ha–1. Development was strongly influenced by the nature of the previous forest. Spruce forest floors were on average more acid and had lower nutrient concentrations, particularly N and Ca. The observed differences suggest that nutrients are recycled more rapidly in the pine plantations, partly explaining the superior growth of the latter. Key words: Forest floor, Kalmia angustifolia L., Picea mariana (Mill.) B.S.P., Pinus banksiana Lamb., nutrient cycling, plantation forest
45
Matangaran, J. R., S. M. Barokah, M. Mujahid, S. Trison e E. I. Putra. "Change of carbon mass after timber harvesting in a natural forest, West Sumatra Indonesia". IOP Conference Series: Earth and Environmental Science 1315, n. 1 (1 marzo 2024): 012040. http://dx.doi.org/10.1088/1755-1315/1315/1/012040.
Testo completoAbstract (sommario):
Abstract Forests have an important role in the carbon cycle and in the dynamics of storing and releasing carbon in growth, decay, and disturbance processes. Timber harvesting initially reduces the amount of carbon in the forest. This study aims to analyze the magnitude of changes in carbon mass due to timber harvesting. It was conducted in a forest concessionaire located at Siberut of West Sumatra on a natural forest covering about 48,000 hectares. Selective cutting was implemented for logging where the harvestable trees were over 50 cm in diameter. The amount of carbon mass was obtained based on laboratory tests on tree parts, including trunk, branches, twigs, and bark. The average carbon content in each part of the tree is different. The trunk contains 53.86% of carbon mass, the branches are 51.98%, the twigs are 31.58%, the leaves are 27.91%, and the bark is 32.01%. Timber harvesting was conducted at the forest compartment with an average forest stand density of 71.5 trees ha−1 and a felling intensity of 8.8 trees ha−1, causing damage to 16.17 trees ha−1 stands. Timber harvesting causes a decrease in carbon mass reserves of 43.26% from forest carbon mass of 141.89 tons C ha−1 before harvesting to 80.00 tons C ha−1 after harvesting.
46
Kettunen, J. "The Forest Cluster and Society". Water Science and Technology 40, n. 11-12 (1 dicembre 1999): 1–3. http://dx.doi.org/10.2166/wst.1999.0687.
Testo completoAbstract (sommario):
The forest industry uses renewable raw materials to produce means necessary for the material and non-material well-being of mankind. Societies set different priorities within the framework of their overall structures. Future scenarios have brought up two major alternatives, namely agreement/political control and technology/enlightened consumer, the latter approach probably having better prospects for global success, but also stronger opposition of traditional structures. Mass production obviously remains dominant in fiber production while other parts of processing approach consumption. For improved productivity, the target of availability should replace ‘bottleneck thinking’. Principles of lean resources and simplicity should be emphasized.
47
Baranovskiy, Nikolay Viktorovich, Viktoriya Andreevna Vyatkina e Aleksey Mikhailovich Chernyshov. "Deterministic–Probabilistic Prediction of Forest Fires from Lightning Activity Taking into Account Aerosol Emissions". Atmosphere 14, n. 1 (24 dicembre 2022): 29. http://dx.doi.org/10.3390/atmos14010029.
Testo completoAbstract (sommario):
Forest fires arise from anthropogenic load and lightning activity. The formation of a thunderstorm front is due to the influence of a number of factors, including the emission of aerosol particles from forest fires. The purpose of this study is mathematical modeling of heat and mass transfer in vegetation firebrand carried out from a forest fire front, taking into account the formation of soot particles to predict forest fire danger from thunderstorm activity. Research objectives: (1) development of a deterministic mathematical model of heat and mass transfer in a pyrolyzed firebrand of vegetation, taking into account soot formation; (2) development of a probabilistic criterion for assessing forest fire danger from thunderstorms, taking into account aerosol emissions; (3) scenario modeling of heat and mass transfer and the formation of a thunderstorm front; (4) and the formulation of conclusions and proposals for the practical application of the developed deterministic–probabilistic approach to the prediction of forest fires from thunderstorms, taking into account aerosol emissions. The novelty of this study lies in the development of a new model of heat and mass transfer in a pyrolyzed vegetation firebrand and a new probabilistic criterion for forest fire danger due to thunderstorm activity, taking into account aerosol emission. The distributions of temperature and volume fractions of phases in a firebrand are obtained for various scenarios. Scenarios of surface fires, crown forest fires, and a fire storm are considered for typical types of coniferous vegetation. Cubic firebrands are considered in the approximation of a two-dimensional mathematical model. To describe the heat and mass transfer in the firebrand structure, a differential heat conduction equation is used with the corresponding initial and boundary conditions, taking into account the kinetic scheme of pyrolysis and soot formation. Variants of using the developed mathematical model and probabilistic criterion in the practice of protecting forests from fires are proposed. Key findings: (1) linear deterministic–probabilistic mathematical model to assess forest fire occurrence probability taking into account aerosol emission and lightning activity; (2) results of mathematical modeling of heat and mass transfer in firebrand taking into account soot formation; (3) and results of scenario modeling of forest fire occurrence probability for different conditions of lightning activity and aerosol emission.
48
Yokelson, R. J., S. P. Urbanski, E. L. Atlas, D. W. Toohey, E. C. Alvarado, J. D. Crounse, P. O. Wennberg et al. "Emissions from forest fires near Mexico City". Atmospheric Chemistry and Physics 7, n. 21 (9 novembre 2007): 5569–84. http://dx.doi.org/10.5194/acp-7-5569-2007.
Testo completoAbstract (sommario):
Abstract. The emissions of NOx (defined as NO (nitric oxide) + NO2 (nitrogen dioxide)) and hydrogen cyanide (HCN), per unit amount of fuel burned, from fires in the pine forests that dominate the mountains surrounding Mexico City (MC) are about 2 times higher than normally observed for forest burning. The ammonia (NH3) emissions are about average for forest burning. The upper limit for the mass ratio of NOx to volatile organic compounds (VOC) for these MC-area mountain fires was ~0.38, which is similar to the NOx/VOC ratio in the MC urban area emissions inventory of 0.34, but much larger than the NOx/VOC ratio for tropical forest fires in Brazil (~0.068). The nitrogen enrichment in the fire emissions may be due to deposition of nitrogen-containing pollutants in the outflow from the MC urban area. This effect may occur worldwide wherever biomass burning coexists with large urban areas (e.g. the tropics, southeastern US, Los Angeles Basin). The molar emission ratio of HCN to carbon monoxide (CO) for the mountain fires was 0.012±0.007, which is 2–9 times higher than widely used literature values for biomass burning. The ambient molar ratio HCN/CO in the MC-area outflow is about 0.003±0.0003. Thus, if only mountain fires emit significant amounts of HCN, these fires may be contributing about 25% of the CO production in the MC-area (~98–100 W and 19–20 N). Comparing the PM10/CO and PM2.5/CO mass ratios in the MC Metropolitan Area emission inventory (0.0115 and 0.0037) to the PM1/CO mass ratio for the mountain fires (0.133) then suggests that these fires could produce as much as ~79–92% of the primary fine particle mass generated in the MC-area. Considering both the uncertainty in the HCN/CO ratios and secondary aerosol formation in the urban and fire emissions implies that about 50±30% of the "aged" fine particle mass in the March 2006 MC-area outflow could be from these fires.
49
Yokelson, R., S. Urbanski, E. Atlas, D. Toohey, E. Alvarado, J. Crounse, P. Wennberg et al. "Emissions from forest fires near Mexico City". Atmospheric Chemistry and Physics Discussions 7, n. 3 (16 maggio 2007): 6687–718. http://dx.doi.org/10.5194/acpd-7-6687-2007.
Testo completoAbstract (sommario):
Abstract. The emissions of NOx and HCN (per unit amount of fuel burned) from fires in the pine-savannas that dominate the mountains surrounding Mexico City (MC) are about 2 times higher than normally observed for forest burning. The NH3 emissions are about average for forest burning. The NOx/VOC mass ratio for the MC-area mountain fires was ~0.38, which is similar to the NOx/VOC ratio in the MC urban area emissions inventory of 0.43, but much larger than the NOx/VOC ratio for tropical forest fires in Brazil (~0.068). The nitrogen enrichment in the fire emissions may be due to deposition of nitrogen-containing pollutants in the outflow from the MC urban area. This effect may occur worldwide wherever biomass burning coexists with large urban areas (e.g. the tropics, southeastern US, Los Angeles Basin). The molar emission ratio HCN/CO for the mountain fires was ~0.0128±0.0096: 2–9 times higher than widely used literature values for biomass burning. The MC-area/downwind molar ratio of HCN/CO is about 0.003±0.0003. Thus, if other types of biomass burning are relatively insignificant, the mountain fires may be contributing about 23% of the CO production in the MC-area (~98–100 W and 19–20 N). Comparing the PM10/CO mass ratio in the MC Metropolitan Area emission inventory (0.011) to the PM1/CO mass ratio for the mountain fires (0.133) then suggests that these fires could produce as much as ~78% of the fine particle mass generated in the MC-area.
50
Metcalfe, D. J., e P. J. Grubb. "Seed mass and light requirements for regeneration in Southeast Asian rain forest". Canadian Journal of Botany 73, n. 6 (1 giugno 1995): 817–26. http://dx.doi.org/10.1139/b95-090.
Testo completoAbstract (sommario):
Seed mass values are given for 140 species of primary lowland rain forest and associated secondary forests in Singapore. Among shade-tolerant species of primary forest there is a trend for a decrease in mean seed mass with tall trees > woody climbers > small trees > shrubs > herbs; the differences between tall trees and small trees or shrubs or herbs, and between herbs and small trees or woody climbers are significant. There are a few light-demanding herbs or shrubs in the primary forest; among small trees, light demanders have significantly lower seed mass values than shade tolerators. In 9 out of 13 comparisons within taxa including both shade tolerants and light demanders the former had appreciably larger seeds than the latter. Two out of 13 comparisons involved very small seeded shade tolerators, and one a notably large-seed light demander. Many shade-tolerant herbs, shrubs, and trees have seed mass values much smaller than those of trees of secondary forest conventionally regarded as small seeded, and exploit moist, litter-free sites, e.g., steep microslopes. The trees of secondary forests on degraded soils do not differ significantly in seed mass from those on nondegraded soils. Key words: seed mass, light requirement, regeneration, tropical rain forest, phylogenetic analysis.