A generalised hybrid process-empirical model for predicting plantation forest growth

A generic model of plantation growth was developed for Australia's National Carbon Accounting System to allow spatial estimation of carbon stocks over time. Unlike the primary goal of most forest growth models, which is to predict log volume at harvest age, the international guidelines for carbon accounting require estimation of current annual increments of total (above and belowground) biomass. In contrast to most commercial forestry systems that are concerned with rotations of many years, capturing the effects of annual climate variability is important, a feature that would otherwise be largely ameliorated over a forest rotation. While yield tables can provide the basis from which empirically based models can predict an 'averaged' performance over time, a process-based model can capture the effects of variability over short time periods. To utilise the valuable empirical data contained in yield tables, while also capturing the effects of process drivers, a hybrid model has been developed that integrates:•a spatially and temporally explicit site class index based on a process model,•a simple growth equation modified by the spatial and temporal site index,•known empirical constraints on growth (as an average) sourced from yield tables,•management effects. Management effects may either increase overall site productivity, and hence biomass accumulation, or accelerate the rate of approach toward site carrying capacity. The effects of management are important and need to be captured in the model. Some 5000 forest management regimes, representing different species, regions, site qualities and variants in management in Australia have been described for application within the model. A national program of identifying both forest areas and forest age classes, using a 30-year archive of Landsat satellite data has been undertaken to provide inputs to the model. Crow

Developing a carbon stocks and flows model for Australian wood products

This paper describes the development of a model for estimating Australia's stocks and flows of carbon in harvested wood products, including estimates of atmospheric emissions. The model estimates emissions in various forms, including those from wood products contained in Australia, encompassing both domestically produced (net of exports) and imported wood products. This estimate is the basis of Australia's National Greenhouse Gas Inventory report on wood products. The model can also estimate emissions from all (and only) wood products produced in Australia, and a third variant that presumes emissions from wood products at the time of harvest. The model represents a collaborative effort, involving relevant Commonwealth and state government agencies, industry groups and research bodies. The model uses available statistics on log flows from forest harvest and estimates of the carbon content of the various wood products processed (for example, sawn timber, plywood, pulp and paper and woodchips) to determine carbon inputs to wood products. The model uses estimates of the decay period of various classes of wood product to calculate the pool of carbon in wood products. Crosschecking with independent input data was done wherever possible to test the robustness of various input data used in the model development. The model is built in Microsoft Excel with all rate and age parameters easily accessed and varied for sensitivity testing using the @Risk software. Wood products in use are assigned to young-, medium- and old-age pools. Simulated losses of wood products from their service life occur from each of the young-, medium-and old-age pools. Material leaving service is either transferred to bioenergy, added to landfill, recycled or emitted to the atmosphere. Losses of carbon can also occur from the landfill pool. The recorded imports and exports of wood products are used to calculate emissions under two approaches. The first is from wood products produced in Australia (but not necessarily remaining within Australia), and the second from wood products stored in Australia (wherever they were produced). Further simulations, with and without consideration of storage and emissions from landfill, are then run for each approach. The results show that an accounting approach that presumes emissions from wood products at harvest over-estimates emissions to the atmosphere when compared with approaches that consider the service life of wood products. The storage of wood products in landfill is also significant

Effects of GnRH administration on ovulation and fertility in ewes subjected to estrous synchronization

The objective of this study was to verify the effects of GnRH on ovulation and pregnancy of ewes subjected to a short-term synchronization of estrus. Santa Inês and crossbred Santa Inês/Dorper ewes received 60 mg MAP sponges during 6 days plus 300 IU eCG and 30 µg d-cloprostenol 24 h prior to sponge withdrawal (SW). Ewes were assigned to receive 0.9% NaCl solution (Tcontrol; n = 32) or 25 µg GnRH (licerelin, T GnRH; n = 34) 24 hours after SW. Each group was assigned to intrauterine insemination by laparoscopy (n = 25) or to natural mating (n = 41). Artificial insemination was performed with a single dose of fresh semen. For controlled mating, females were exposed to males 12, 24, 36 and 48 hours after SW. Ten females per treatment were subjected to transrectal ultrasound examination at 12-hour intervals (SW to 60 hours after). Estrous response (100.0% vs 95.2%), interval from SW to estrus (32.9±7.4 vs 29.8±6.9 hours), estrous length (37.4±9.0 vs 31.5±10.4 hours), pregnancy rates (57.0% vs 41.0%), ovulation rate (100.0% vs 90.0%), number of ovulations/ewe (1.1±0.3 vs 1.2±0.4), maximum follicular diameter (6.4±0.7 vs 6.1±0.6 mm), interval from SW to ovulation (59.1±3.5 vs 58.4±3.5 hours) did not differ between Tcontrol and T GnRH, respectively. Administration of GnRH 24 hours after SW does not improve ovulation or pregnancy rate in estrous synchronization in ewes

Microbiological and functional evaluation of an alternative device (OB®) for estrous synchronization in ewes Avaliação microbiológica e funcional de um dispositivo vaginal alternativo (OB®) para sincronização de cio em ovelhas

The use of synthetic progestagens released by vaginal devices is an important tool to overcome the reproductive seasonality in sheep, but cost and/or subsequent vaginitis are limiting factors for their use. To identify economic, simple and innocuous alternative vaginal devices for estrous synchronization/induction protocols in sheep, this study aimed to evaluate the microbiological and functional viability of the human vaginal tampons (OB®) impregnated with medroxyprogesterone acetate (MAP) on reproductive performance of ewes. The study compared them with commercial vaginal inserts (CIDR®) and polyurethane sponges impregnated with MAP. In Experiment 1, the device loss rate, the degree of vaginitis during the device removal, the count and identification of bacterial colonies at the device insertion and removal, and efficiency in estrous synchronization and estrus temporal distribution were evaluated. Pubertal ewes at the beginning of the breeding season were randomly allocated to three experimental groups: CIDR®, PSP (polyurethane sponge) and OB®. No device losses occurred in any group, but the use of OB® caused milder signs of vaginitis than polyurethane sponges, with a similar vaginal bacterial growth and microbiota than the CIDR group. The estrus distribution was more disperse in the CIDR than PSP or OB groups. In Experiment 2, pregnancy rates using CIDR® or OB® devices were compared, with estrus manifestation (85.4% and 89.8%) and pregnancy rates (58.3% and 49.0%) being similar between groups (P>0.05), respectively. In conclusion, the use of human intra-vaginal tampons (OB®) impregnated with MAP was proven highly hygienic, practical and effective as a low-cost alternative for estrous synchronization and AI in sheep.<br>O uso de progestágeno sintético liberado por pessários vaginais é uma importante ferramenta para suplantar a sazonalidade reprodutiva em ovelhas. Todavia, seu uso é limitado pelo custo ou pelas subsequentes vaginites. Na busca de uma alternativa simples e de baixo custo para sincronizar estro em ovelhas, este estudo avaliou o tampão vaginal humano (OB®) impregnado com MAP, na performance reprodutiva de ovelhas, comparando com o CIDR® e as esponjas de poliuretano, estas também impregnadas com MAP. No experimento 1 foram avaliados a taxa de perdas; o grau das vaginites no momento da remoção do pessário; a contagem e identificação das colônias bacterianas; bem como a eficiência da sincronização e a distribuição temporal dos cios. As ovelhas foram aleatoriamente distribuídas em um de três grupos experimentais: CIDR, Esponjas e OB, no inicio da estação reprodutiva. Não ocorreram perdas de pessários em qualquer grupo, porém o OB causou menor grau de vaginite em relação às esponjas, com um crescimento bacteriano e microbiota similares ao grupo CIDR. A distribuição dos cios foi mais dispersa no grupo CIDR do que nos grupos Esponja ou OB. No experimento 2, foram comparados o CIDR e OB em relação à manifestação de cio (85,4% e 89,8%) e taxa de prenhez (58,3% e 49,0%), que foram similares (P<0,05). Conclui-se que o pessário OB impregnado com MAP é higiênico, de baixo custo, prático e efetivo como para a sincronização de cios e IA em ovelhas