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Shinichi Tatsumi Toshiaki Owari Hisatomi Kasahara Yuji Nakagawa 《Journal of Forest Research》2014,19(4):369-378
Quantifying tree damage and mortality caused by single-tree selection harvesting is critical to understanding postharvest forest dynamics and management. In this study, we quantified the effects of tree size and species and the distance from residual trees to felled trees and skid trails on damage to residual trees and mortality in mixed coniferous–broadleaved stands of Hokkaido, northern Japan. Among the 4,961 trees that we studied, 373 (7.5 %) were damaged, and 148 of these trees (3.0 %) died during or immediately after logging. Hierarchical Bayesian modeling showed that the risk of damage to residual trees increased with increasing size of the felled trees and with increasing proximity to felled trees and skid trails. Smaller residual trees had the greatest risk of damage. Species differed in their susceptibility to damage; Abies sachalinensis (Fr. Schm.) Masters and Picea jezoensis (Sieb. et Zucc.) Carr. were the most susceptible species in our sample plots. Smaller damaged trees had the highest risk of mortality. The damaged trees that did not die at the time of logging had a higher risk of postharvest mortality than undamaged trees. Our results indicate that, to minimize logging-induced damage and mortality: (1) the spatial arrangement of skid trails should be optimized and fixed, (2) the risk of skidding damage should be considered before marking the trees to be harvested and choosing the felling direction, and (3) logging operators should be instructed to avoid damaging small trees, especially those of the species that are most susceptible to damage. 相似文献
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Effects of silviculture treatments in a hurricane-damaged forest on carbon storage and emissions in central Hokkaido,Japan 总被引：1，自引：0，他引：1
Hurricanes cause abrupt carbon reduction in forests, but silviculture treatment can be an effective means of quickly regenerating and restoring hurricane-damaged sites. This study assessed how silviculture treatments affect carbon balance after hurricane damage in central Hokkaido, Japan. We examined carbon storage in trees and underground vegetation as well as carbon emissions from silviculture operations in 25-year-old stands, where scarification and plantation occurred just after hurricane damage. The amount of carbon stored varied according to silviculture treatment. Among three scarification treatments, a scarified depth of 0 cm (understory vegetation removal) led to the largest amount of carbon stored (64.7 t·ha-1 C). Among four plantation treatments, the largest amount of carbon was stored in a Larix hybrid (L. gmelinii var. japonica × L. kaempferi) plantation (80.3 t·ha-1 C). The plantation of Abies sachalinensis was not successful at accumulating carbon (40.5·ha-1 C). The amount of carbon emitted from silviculture operations was 0.05-0.14 t·ha-1 C, and it marginally affected the net carbon balance of the silviculture project. Results indicate that silviculture treatments should beperformed in an appropriate way to effectively recover the ability of carbon sequestration in hurricane-damaged forests. 相似文献
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Determining forest structural complexity,i.e.,a measure of the number of different attributes of a forest and the relative abundance of each attribute,is important for forest management and conservation.In this study,we examined the structural complexity of mixed conifer–broadleaf forests by integrating multiple forest structural attributes derived from airborne Li DAR data and aerial photography.We sampled 76 plots from an unmanaged mixed conifer–broadleaf forest reserve in northern Japan.Plot-level metrics were computed for all plots using both field and remote sensing data to assess their ability to capture the vertical and horizontal variations of forest structure.A multivariate set of forest structural attributes that included three Li DAR metrics(95 th percentile canopy height,canopy density and surface area ratio) and one image metric(proportion of broadleaf cover),was used to classify forest structure into structural complexity classes.Our results revealed significant correlation between field and remote sensing metrics,indicating that these two sets of measurements captured similar patterns of structure in mixed conifer–broadleaf forests.Further,cluster analysis identified six forest structural complexity classes includingtwo low-complexity classes and four high-complexity classes that were distributed in different elevation ranges.In this study,we could reliably analyze the structural complexity of mixed conifer–broadleaf forests using a simple and easy to calculate set of forest structural attributes derived from airborne Li DAR data and high-resolution aerial photography.This study provides a good example of the use of airborne Li DAR data sets for wider purposes in forest ecology as well as in forest management. 相似文献
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Fan Zhou Wenxin Song Qingjun Shao Xiang Peng Jinxing Xiao Ying Hua Bergo Ngandzali Owari Tingzhou Zhang Wing‐Keong Ng 《Journal of the World Aquaculture Society》2011,42(2):184-197
The effect of fish meal (FM) substitution with fermented soybean meal (FSBM) in the diets of the carnivorous marine fish, black sea bream, Acanthopagrus schlegelii, was investigated. An 8‐wk feeding trial was conducted with black sea bream (11.82 ± 0.32 g; mean initial weight) in indoor flow‐through fiberglass tanks (25 fish per tank). Six isonitrogenous and isoenergetic diets were formulated, in which FM was replaced by FSBM at 0% (control diet), 10% (FSBM10), 20% (FSBM20), 30% (FSBM30), 40% (FSBM40), or 50% (FSBM50), respectively. Each diet was fed to triplicate groups of fish twice daily to apparent satiation. The results showed that there was no difference in survival of black sea bream during the feeding trial. Fish fed the FSBM10 or FSBM20 diet showed comparable growth performance compared with fish fed the control diet (P > 0.05), whereas more than 30% replacement of FM adversely affected weight gain and specific growth rate (P < 0.05). Feed intake was significantly lower for fish fed the FSBM50 diet compared with fish fed the control diet. Feed conversion ratio (FCR) tended to increase with increasing dietary FSBM with the poorest FCR observed for fish fed the FSBM50 diet. Protein efficiency ratio and protein productive values showed similar patterns. Apparent digestibility of nutrients significantly decreased with increasing dietary FSBM level. With the exception of protein content, no significant differences in whole body and dorsal muscle composition were observed in fish fed the various diets. Fish fed the FSBM50 diet had significantly lower intraperitoneal ratio than fish fed the control or FSBM10 diet. Hepatosomatic index and condition factor were unaffected by dietary treatments. This study showed that up to 20% of dietary FM protein could be replaced by FSBM protein in the diets of juvenile black sea bream. 相似文献
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Fan Zhou Wen Xiong Jin‐Xing Xiao Qing‐Jun Shao Owari Ngandzali Bergo Ying Hua Xuejun Chai 《Aquaculture Research》2010,41(10):e418-e430
An 8‐week feeding trial was conducted to determine the dietary arginine requirement of juvenile black sea bream Sparus macrocephalus in 18 350 L indoors flow‐through circular fibreglass tanks. Six isonitrogenous and isoenergetic diets were formulated to contain graded levels of l ‐arginine (1.85%, 2.23%, 2.51%, 2.86%, 3.20% and 3.46% dry diet) from dietary ingredients and crystalline arginine. Each diet was randomly assigned to triplicate groups of 25 juvenile fish (10.51±0.15 g) twice daily (08:00 and 16:00 hours) to apparent satiation. Results showed that the specific growth rate (SGR) increased with increasing dietary arginine levels up to 2.51% and remained nearly the same thereafter. Feed efficiency ratio, protein efficiency ratio (PER) and protein productive value all showed an increasing tendency and then levelled off. Apparent digestibility coefficients of dry matter, crude protein and gross energy significantly improved up to 2.86% arginine diet and decreased at different extents thereafter. Fish fed 1.85% arginine diet had significantly lower protein content in the whole body and dorsal muscle than those fed diets supplemented with or >2.86% of arginine. Lipid content decreased and lower value occurred at 3.46% of dietary arginine. The dietary essential amino acid composition in the whole body of the black sea bream was significantly influenced by dietary arginine. Arginine retention increased with an increasing dietary arginine level from 1.85% to 3.20%, then declined slightly at 3.46% arginine diet. Serum biochemical parameters were significantly affected by the dietary arginine level except for the cholesterol content. Broken‐line regression based on SGR and second‐order polynomial regression based on PER indicated that the optimum dietary arginine requirements for juvenile black sea bream were 2.79% and 3.09% diet, corresponding to 7.74% and 8.13% of the dietary protein respectively. 相似文献
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C. Nebbia M. Dacasto L. Ceppa M. Gennaro Soffietti P. Spinelli V. Bergo P. Di Simplicio 《Veterinary research communications》1997,21(2):117-125
Nebbia, C., Dacasto, M., Ceppa, L., Gennaro Soffietti, M., Spinelli, P., Bergo, V. and Di Simplicio, P., 1997. The comparative effects of subchronic administration of triphenyltin acetate (TPTA) on the hepatic and renal drug-metabolizing enzymes in rabbits and lambs. Veterinary Research Communications, 21 (2), 117-125The purpose of this study was to determine whether subchronic (70 days) oral exposure to moderate to high levels of triphenyltin acetate (TPTA), an organotin derivative used worldwide, would affect the microsomal hepatic and renal drug-metabolizing enzymes in rabbits and lambs. Rabbits were offered a diet containing 0, 15, 75 or 150 ppm TPTA, while lambs were daily given 0, 1.5 or 7.5 mg TPTA per kg bw. The tin content in the liver and kidneys was measured by atomic absorption spectrophotometry. In the rabbits' livers, TPTA failed to affect the cytochrome P450 content, or the oxidative, hydrolytic (carboxylesterase) or conjugative (UDPG-transferase) enzyme activities studied. In contrast, a striking dose-related increase in both P450 content and carboxylesterase activity (up to 280%) was detected in the rabbits' kidneys, but the ECOD and EROD activities were respectively unchanged or moderately depressed. None of the enzymes studied showed statistically significant changes in the ovine hepatic or renal subfractions. The results suggest that repeated exposure to TPTA could lead to the induction of a particular P450-isoenzyme in rabbit kidneys which is concerned with the metabolism of endogenous compounds (e.g. steroids, prostaglandins, thromboxanes). The lack of significant tissue- and species-related differences in the concentration of tin supports the hypothesis that the changes observed in the rabbits' kidneys may not have been caused solely by the accumulation of the metal in the tissues. 相似文献
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n-3高不饱和脂肪酸对黑鲷幼鱼生长及脂肪代谢的影响 总被引：1，自引：1，他引：0
研究了饲料中不同水平n-3 HUFA(0.79%,0.83%,0.85%,0.88%,0.92%,0.94%;DHA/EPA=2.8/1)对黑鲷幼鱼生长及脂肪代谢的影响.结果显示:(1)黑鲷幼鱼肝体指数(HSI)及腹脂率(IPF ratio)随饲料中n-3 HUFA含量的增加而减小,且于0.92%和0.94%组时显著低于其他各组;脂肪细胞直径呈减小趋势,其中0.94%组显著小于0.85%组;肌肉脂肪含量受n-3 HUFA的影响显著,于0.88%组时达到最低.各组全鱼水份和脂肪含量差异不显著(P＞0.05).肝脏、肌肉及腹腔脂肪组织饱和脂肪酸(∑SFA)和C16:0含量均随饲料n-3HUFA水平增加呈下降趋势,而∑n-3 HUFA呈显著上升趋势.各组织中DHA/EPA不受饲料脂肪酸组成的影响.以增重率为参考指标,二次回归分析结果表明,黑鲷幼鱼[(8.08±0.09)g]获得最佳增重时对饲料中n-3 HUFA的需要量为0.87%DM;(2)黑鲷幼鱼肝脏脂肪酸合成酶(FAS)活性及基因表达水平均在n-3 HUFA＞0.92%时有显著下降(P＜0.05);腹腔脂肪激素敏感脂肪酶(HSL)活性及基因表达水平均随饲料中n-3 HUFA的添加呈升高趋势(P＜0.05),且高含量n-3 HUFA(0.94%)可使HSL活性增加近一倍.结果表明,饲料中n-3HUFA通过同步调控脂肪合成与分解两个过程影响黑鲷幼鱼脂肪代谢. 相似文献
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