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The entry of forestry carbon sequestration products into the carbon trading mechanism is conducive to giving full play to the emission reduction function of the forestry ecosystem. Value accounting of forestry carbon sequestration products can endow forestry carbon sequestration with economic value. We review the evolution of emission reduction mechanisms of forestry carbon trading in China and abroad and take forest carbon sequestration products as the research object to analyze the correlation between forestry carbon sequestration products and forestry carbon sequestration projects. Based on the dual benefits of wood and carbon sequestration, this study uses the net present value method to summarize the applicability of three carbon accounting models for forestry carbon sequestration products. We further compare the models on the aspects of carbon price fluctuation response, tree species applicability, and management characteristics of forestry carbon sequestration projects. This study finds that: (1) Forestry carbon sequestration can realize the dual value of climate emission reduction and economic benefits through voluntary carbon emission reduction and mandatory carbon trading mechanisms. However, China's forestry carbon sequestration faces problems such as unclear product definition and mismatch in accounting methodology. (2) The value accounting of forestry carbon sequestration products should be based on the optimal rotation period and 'carbon amount' of forestry carbon sequestration projects. Three types of forestry carbon sequestration products, tCER, lCER, and CCER, are identified based on the time period. tCER and lCER can be used to solve the non-persistence of forestry projects. Through permanent credit and a stable pricing mechanism, CCER can improve the effectiveness of emission reduction of forestry carbon sequestration products. (3) The core value of forestry carbon sequestration products lies in their carbon storage capacity and carbon level. Its value accounting should take ' carbon amount' as the basic premise. Combined with the calculation standards of carbon storage, the carbon accounting models of forestry carbon sequestration products are classified into total carbon model, carbon increment model, and carbon average model. (4) In terms of carbon price fluctuation response, the carbon average model can mitigate the impact of carbon price fluctuation through the whole project. In terms of carbon sink tree species, the total carbon model is suitable for slow-growing tree species, the carbon increment model is suitable for fast-growing tree species, and the carbon average model is more suitable for adjusting tree species selection schemes according to ecological value. In terms of project management characteristics, the carbon increment model is suitable for a long-term management scheme, while the carbon average model can be combined with the historical baseline of the project, making it easier to formulate a reasonable carbon reserve level. [ABSTRACT FROM AUTHOR]

This paper presents the results of the photometric CCD observations of the NEA (2100) Ra-Shalom carried out on August 24–29, 2019, at the 1-m telescope of the Sanglokh Observatory of the Institute of Astrophysics, National Academy of Sciences of the Republic of Tajikistan. The rotation period P = 19.8 ± 0.1 h was determined. Composite light curves were plotted in the photometric BVR bands; the brightness amplitude ΔV = 0.61m ± 0.05m and the average values of the color indices B–V = 0.75m ± 0.05m, V–R = 0.40m ± 0.02m were determined. Variations in the color indices with rotation period are within the measurement errors, which indicates that the reflectivity of Ra-Shalom's surface is uniform. The absolute stellar magnitude of the asteroid is 15.91m ± 0.10m. The ratio of the asteroid's axes a/b = 1.75. [ABSTRACT FROM AUTHOR]

The wear process of the wheel flange and the rolling circle diameter was described by the Gamma random process， and the method of calculating the reliability of the wheel flange degradation and the rolling circle diameter degradation was studied by using the Copula function and the fourth-order moment method， and the dynamic indexes of the train at different stages were obtained by dynamics software simulation. The reliability of the wheel degradation process with a rotation cycle of 200，000 km and the sensitivity of the wheel diameter degradation process were studied. The correctness of the method was verified by Monte Carlo simulation (MCS).The results showed that the reliability of wheels reaching the expected life is high when the rotation cycle is 200，000 km， and the reliability calculated based on the Copula function correlation failure degradation model is higher than that calculated by the independent failure model. The sensitivity study of the wheel diameter degradation reliability model indicates that the scheme with less reduction of wheel diameter should be selected during the rotation repair. [ABSTRACT FROM AUTHOR]

The asteroid (13553) Masaakikoyama was observed with the ZA-320M and MTM-500M telescopes of the Pulkovo observatory in August and September 2018. Its axial rotation period was estimated based on the observed sections of the light curve (and additional observational data provided by B.D. Warner) at 97.2 ± 0.3 h. This estimation was made difficult by the fact that the period is commensurable with a day. The light curve has certain features suggestive of tumbling rotation and a complex shape. The orbit of (13553) Masaakikoyama was improved using the obtained astrometric positions of the asteroid. [ABSTRACT FROM AUTHOR]

Results of astrometric and BVRI photometric observations of the active asteroid (596) Scheila are presented. The observations were carried out at the Zeiss-1000 telescope of the Sanglokh International Astronomical Observatory of the Institute of Astrophysics of the Academy of Sciences of the Republic of Tajikistan on June 16−17 and from July 30 to August 1, 2017. The coordinates of the object and its orbit were determined; and the apparent brightness in four filters, the absolute brightness in the V and R filters, and the color indices were obtained. The light curves suggest that no substantial changes in the asteroid’s brightness occurred during the observations. The absolute brightness of the asteroid in the V and R filters was (9.1 ± 0.05)m and (8.8 ± 0.03)m, respectively. The mean value of the asteroid diameter was (119 ± 2) km. The mean values of the color indices (B−V = (0.72 ± 0.05)m, V−R = (0.29 ± 0.03)m, and R−I = (0.31 ± 0.03)m) agree well with the values for asteroids of the P- and D-types and its averages. The rotation period of the asteroid estimated from photometric observations was 16.1 ± 0.2 h. The analysis of the data has shown that the asteroid continues to exhibit the same values of absolute brightness and other characteristics as those before the collision with a small body in December 2010, though the latter resulted in the outburst event and cometary activity of the asteroid. Most likely, the collision of asteroid (596) Scheila with a small body did not lead to catastrophic changes in the surface of the asteroid or to its compete break-up. [ABSTRACT FROM AUTHOR]

We investigate the influence of the rotation period (Prot) on the mean climate of an aquaplanet, with a focus on the role of sea-ice albedo. We perform aquaplanet simulations with the atmospheric general circulation model ECHAM6 for various rotation periods from one Earth-day to 365 Earth-days in which case the planet is synchronously rotating. The global-mean surface temperature decreases with increasing Prot and sea ice expands equatorwards. The cooling of the mean climate with increasing Prot is caused partly by the high surface albedo of sea ice on the dayside and partly by the high albedo of the deep convective clouds over the substellar region. The cooling caused by these deep convective clouds is weak for non-synchronous rotations compared to synchronous rotation. Sensitivity simulations with the sea-ice model switched off show that the global-mean surface temperature is up to 27 K higher than in our main simulations with sea ice and thus highlight the large influence of sea ice on the climate. We present the first estimates of the influence of the rotation period on the transition of an Earth-like climate to global glaciation. Our results suggest that global glaciation of planets with synchronous rotation occurs at substantially lower incoming solar irradiation than for planets with slow but non-synchronous rotation. [ABSTRACT FROM AUTHOR]

During 2013–2015 the photometric observations of the EnviSat satellite, which became space debris after the failure in April 2012 in low Earth orbit, were performed. The rotation pole position and slow change in sidereal rotation period were updated on the basis of analysis of specular glints observed in 222 light curves using reduction of synodic periods. Apparently, there are minor oscillations of the rotation pole near the normal to the orbital plane. The sense of the EnviSat’s spinning is opposite to the sense of its orbital rotation. The sidereal period is best approximated by the second-order polynomial: P sid ( sec ) = 0.000021534 · T 2 + 0.04936003 · T + 121.18195 where T is measured in days from the beginning of 2013. This method being applied to another representative of space debris, namely the Cbers-2B satellite, has shown a similar result: there is not precise solution for the rotation pole either as it undergoes oscillations with various time scale from several hours to several months. In 2014, the spin axis made the 10 ° angle with the normal to the orbital plane while the sense of spinning is direct in this case, i.e. coincides with the sense of orbital rotation. The sidereal period is best approximated by the following expression: P sid ( sec ) = 0.000029543 · T 2 + 0.08094931 · T + 81.31775 where T is measured in days starting from March 10, 2014. This method allows of controlling slow changes in the spatial orientation of the rotation axis of the satellites in which specular reflection of light from flat faces of the surface is inherent. [ABSTRACT FROM AUTHOR]

Silver birch is widely used both in forest regeneration and afforestation of abandoned agricultural lands, since it has high productivity and phenotypic plasticity and is relatively seldom damaged by biotic or abiotic factors. In Baltic States significant browsing damage of this tree species had not been noted in contrast to other countries with notably higher ungulate population densities. Therefore the aim of our study was to evaluate the impact of browsing damages on tree and stand parameters as a basis for further recommendations for stand protection. Data for the analysis were collected in central Latvia (56°22´N, 23°7´E) in a large plantation with areas of different browsing intensity. At the age of 16 years, tree height and diameter was measured and traits characterising damages were assessed. Browsing had caused a significant decrease in survival: from 87% survival in areas with light browsing to 56% survival in areas with heavy browsing. Browsing had caused a reduction of tree growth: mean tree height in areas with slight browsing was 13 ± 0.4 m, but only 2 ± 0.3 m (i.e. reaching height of red deer and moose) in areas with heavy browsing. Heavy browsing had created irreversible loss of productivity: even if browsing would not continue, it would take double as much time for the birches in these areas to reach target diameter for cutting (27 cm) than in slightly browsed areas. Frequency of spike knots and crooked stems was statistically significantly higher for trees with browsing damage. [ABSTRACT FROM AUTHOR]

The aim of this article is to present research on the relationship between forest stand age and its functional effect. Forest ecosystem (forest stand) age together with its stocking and health condition is specified as criterion characterizing forest stand (with simplified structure) actual stage, dynamics and functional effect on a base of realized analysis of wide spatial and time forest stand parameters data set. The criterion "forest ecosystem development phases" is used for forest age structure expression. It represents the percentage of forest stand age from a predicated period of its existence - rotation period. There were realized development dynamics analyses of particular forest functions and actual functional effects; forest stand age weight development as a reducing criterion for different forest stand conditions and model real effect of the forest functions development for chosen stand types. Research was carried out at the state enterprise Lesy ČR, s.p., organization unit Židlochovice. The results present a synergistic effect of functional reduction criterion on the real effect of forest stand functions. Simultaneously, the higher the forest stand age, the higher the importance of the forest stand condition and stocking. [ABSTRACT FROM AUTHOR]

Knowledge of the physical properties of asteroids is required in order to calculate the evolution of their orbits under the influence of nongravitational effects. Photometric observations of the potentially hazardous asteroid 275677 were conducted at the Sayan Solar Observatory of the Institute of Solar-Terrestrial Physics from March 25, 2014, through April 4, 2014 (at the time when this asteroid approached Earth). The period of rotation of the asteroid about its center of mass and the light curve, which defines the phase dependence of its brightness in a single rotation period, were determined based on the results of measurements performed by the Lafler-Kinman method. A model was constructed based on the obtained light curve. When this model was rotated, the variable component of the reflected radiation in a single revolution matched the variable component of the light curve of the asteroid. The range of possible directions of the axis of rotation of the asteroid was determined in the process of modeling. [ABSTRACT FROM AUTHOR]

Litter fall and its decomposition rate play an important role in nutrient recycling, carbon budgeting and in sustaining soil productivity. Litter production and the decomposition rate were studied on commonly planted broad-leaved Eucalyptus (Eucalyptus globulus, Eucalyptus camaldulensis, Eucalyptus saligna) and coniferous (Juniperus procera, Cupressus lusitanica, Pinus patula) plantation species and compared with the adjacent broad-leaved natural forest. The production of litter was recorded by litter traps and the decomposition rate was studied by nylon net bag technique. Litter production under broad-leaved plantation species and natural forest (that varied from 9.7 to 12.6 Mg ha−1 y−1) was significantly higher (p<0.05) than that under coniferous species (that varied from 4.9 to 6.6 Mg ha−1 y−1). The average concentration of C and N in fresh mature leaves was higher than in leaf-litter fall, implying that both C and N were either sorbed in the plant system or lost through decomposition, leaching or erosion during the leaf-litter fall period. The amount of N, which potentially returned to the soil through the leaf-litter fall, tended to be higher in natural forest than in Eucalyptus plantations. The residual litter mass in the litter bag declined with time for all species. The annual dry matter decay constant (k) varied from 0.07 m−1 in Pinus patula to 0.12 m−1 in Eucalyptus saligna. The half-time (t0.5) decay varied from 6.0 for Eucalyptus saligna to 9.7 months for Pinus patula. The results suggest that the decomposition rate in Pinus patula was relatively lower than the other species and the litter production under broad-leaved Eucalyptus was comparatively higher than that in coniferous species. Overall the litter decomposition was fast for all species. The higher litter production and its relative faster rate of decomposition is a positive aspect to be considered during species selection for the restoration of degraded habitats given other judicious management practices such as prolonging the rotation period are adhered to. [ABSTRACT FROM PUBLISHER]

Extensive observations of comet C/2004 Q2 (Machholz) were carried out between August 2004 and May 2005. The images obtained were used to investigate the comet's inner coma features at resolutions between 350 and 1500 km/pixel. A photometric analysis of the dust outflowing from the comet's nucleus and the study of the motion of the morphological structures in the inner coma indicated that the rotation period of the nucleus was most likely around 0.74 days. A thorough investigation of the inner coma morphology allowed us to observe two main active sources on the comet's nucleus, at a latitude of +85±5 and +45±5, respectively. Further sources have been observed, but their activity ran out quite rapidly over time; the most relevant was at lat=25±5. Graphic simulations of the geometrical conditions of observation of the inner coma were compared with the images and used to determine a pole orientation at RA=95±5, Dec=+35±5. The comet's spin axis was lying nearly on the plane of the sky during the first decade of December 2004. [ABSTRACT FROM AUTHOR]

Abstract: Anderson and Schubert [2007. Saturn''s Gravitational field, internal rotation, and interior structure. Science 317, 1384–1387 (paper I)] proposed that Saturn''s rotation period can be ascertained by minimizing the dynamic heights of the 100mbar isosurface with respect to the geoid; they derived a rotation period of 10h 32m 35s. We investigate the same approach for Jupiter to see if the Jovian rotation period is predicted by minimizing the dynamical heights of its isobaric (1bar pressure level) surface using zonal wind data. A rotation period of 9h 54m 29.7s is found. Further, we investigate the minimization method by fitting Pioneer and Voyager occultation radii for both Jupiter and Saturn. Rotation periods of 9h 55m 30s and 10h 32m 35s are found to minimize the dynamical heights for Jupiter and Saturn, respectively. Though there is no dynamical principle requiring the minimization of the dynamical heights of an isobaric surface, the successful application of the method to Jupiter lends support to its relevance for Saturn. We derive Jupiter and Saturn rotation periods using equilibrium theory to explain the difference between equatorial and polar radii. Rotation periods of 9h 55m 20s and 10h 31m 49s are found for Jupiter and Saturn, respectively. We show that both Jupiter''s and Saturn''s shapes can be derived using solid-body rotation, suggesting that zonal winds have a minor effect on the planetary shape for both planets. The agreement in the values of Saturn''s rotation period predicted by the different approaches supports the conclusion that the planet''s period of rotation is about 10h 32m. [Copyright &y& Elsevier]

Abstract: The long time photometric observations were carried out for eight asteroids: (122) Gerda, (153) Hilda, (190) Ismene, (221) Eos, (411) Xanthe, (679) Pax, (700) Auravictrix, (787) Moskva. New rotation periods have been determined for the asteroids (153) Hilda (5.959h) and (411) Xanthe (11.408h), and known rotation periods for some of the others have been confirmed. Using our data and others data we have estimated new pole coordinates for the observed asteroids. [Copyright &y& Elsevier]

Achieving the carbon neutral targets before year 2060 is one of the important commitments for mitigating global climate change by Chinese government. However, the manner in which one would maximize the carbon sequestration of the planted forests is still unclear. Estimating accurately the carbon balance in forestry depends highly on the dynamics of numerous delay-released carbon pools (e.g., harvest residues, wood products), thus the strategies used to account for the carbon emissions of these components may have great influences on the decision-making and profitability associated with planted forests. This study developed a tool that allows forest managers and policy makers to analyze the effects of alternative accounting strategies for recognizing carbon emissions on the optimal rotation lengths and profitability of planted forests. The considered carbon balance not only refers to the within-forest pools, e.g., living biomass, harvest residues, annually generated litters and dead trees, but also refers to the outside-forest pools that include wood products, biofuel, operating process and substitution effect. The obtained results indicated that the lengths of optimal forest rotation decreased significantly with increases in site index, planting density and discount rate, while they increased dramatically with increases of carbon price. The gaps in rotation lengths were as large as 13.5 years, 6.9 years, 27.6 years and 11.0 years, respectively for the ranges of site index (10–18 m), planting density (2500–4444 trees per hectare), discount rate (1%–5%), and carbon prices (0–880 CNY/ton CO 2) assumed. The effects of delay-released carbon pools on the optimal rotation lengths were not significant, when the substitution effects of wood products and biofuels were considered under the current carbon trading markets; however, some exceptions were observed when a very high carbon price (880 CNY/ton CO 2) was assumed. [Display omitted] • A management tool that considers carbon balance and wood production was developed. • The optimal rotations are sensitive to forest- and economic-based variables. • The delayed effects of carbon emissions on optimal rotations were offset by substitution effects. • Pricing CO 2 sequestrated in forests can increase optimal rotations and profitability. [ABSTRACT FROM AUTHOR]

A number of studies have suggested that incentives for carbon sequestration could lead to longer rotation periods for even-aged managed forests. In this article we examine the potential costs and quantity of sequestered carbon from extending rotation ages in softwood forests of the southern and western USA. A model of optimal rotations when carbon is a valued asset was developed to show how optimal rotations adjust when carbon is priced. Data on 324 types and site classes of softwood forests in southern and western states of the USA were used to examine the costs of extending rotations. The results were then aggregated by applying the marginal cost curves to inventory data within each county in these states. The results indicate that in these 12 states, about 15 million tCO2 could be sequestered for less than $7/ tCO2 (1 tCO2 = 1,000 kg CO2), although for substantially higher carbon prices of $55/tCO2, up to 209 million tCO2 could be sequestered. Timber prices were found to have an important influence on the marginal costs of carbon sequestration, with site quality being of secondary importance. The results also showed that at $55/tCO2 potentially 1 million ha of softwood forests could be set aside, mostly in the western states. [ABSTRACT FROM AUTHOR]