京津风沙源治理和退耕还林工程区农户支出分析

2007年项目区农户总消费支出中,京津风沙源治理工程项目区农户,在生活消费方面比退耕还林工程项目区农户少支出1080.54元,医疗消费方面多支出241.89元,教育消费方面多支出1412.02元,总计多支出717.20元。2008年,京津风沙源治理工程项目区农户,在生活消费方面比退耕还林工程项目区农户少支出1249.88元,医疗消费方面多支出374.14元,教育消费方面多支出1469.13元,总计多支出1079.31元。结果表明,京津风沙源治理工程项目区农民生活水平高于退耕还林工程项目区的农民。     

保松灵防治松墨天牛的林间试验

松材线虫病 [Bursaphelenchus xylophilus (Steiner et Buhrer) Nickle]严重威胁我国的森林资源。浙江等地每年因该病造成大量松树枯死 ,防治松材线虫病刻不容缓。当前 ,我国防治该病主要措施是清理枯死松树 ,降低媒介昆虫松墨天牛 (Monochamus alternatus Hope)密度 ,减缓病害扩散蔓延。但在风景名胜区的松林和古树名木等 ,一旦发生该病 ,仅清理死树是不够的 ,必须采取保护性措施 ,防止因病害导致大量宝贵松树枯死。在日本 ,长期以来主要措施是在松树树冠进行空中或地面喷洒杀螟松、倍硫磷、西维因等农药 ,杀灭松墨天牛成虫 ,从而防治松…     

树叶中重金属含量及其指示大气污染的研究

通过对南京市区交通流量大的区域和相时清洁区(江苏省林科院)不同植物叶片重金属元素(Pb、Cd、Cu)含量的分析,研究了大气污染指数,初步探讨了植物重金属含量与城市大气污染之间的关系.研究表明.植物叶片中重金属Pb、Cd和Cu的累积量与大气中Pb、Cd和Cu的相对含量呈显著正相关;所调查绿化树种叶片的重金属含量因重金属种类、采样区和树种的不同具有明显差异,悬铃木叶片累积Pb的能力最强,而杨树叶片对Cd和Cu的累积能力最强.市区大气重金属质量状况为:交通枢纽区中央门、南京化工厂和沪宁高速属于重污染,生活区新庄属于中轻度污染,远郊林科院属于无污染区.     

Comparative study of the stoichiometric characteristics of karst and non-karst forests in Guizhou,China

Carbon (C), nitrogen (N), and phosphorous (P) levels and their stoichiometry in plant components (leaves, branch trunks, roots) of trees in a karst forest and non-karst forest are compared. The results show that the C contents, C:N and C:P ratios of dominant species in the karst forest were lower than those in the non-karst forest, but the N and P and the N:P ratio were higher;C:N:P ratios in plant organs of trees in the karst forest were in the order of trunks>roots>branches>leaves. However, C:N:P ratio in the non-karst forest trees were trunks>branches>roots>leaves. Moreover, ratio of C:N:P in trunks was highest and lowest in leaves in both forests. In non-karst forest trees, N:P was in the order of leaves> roots>branches>trunks. There were no significant differences in the ratio of N:P in different plant components of trees in the karst forest. However, in karst and non-karst forest trees, the ratio of N:P in leaves was highest;positive correlations between N and P contents, and N and N:P ratios were observed in both karst and non-karst forests (p<0.001). Negative correlations between P and N:P ratios (p<0.05) were observed in karst forest trees, while positive correlations were observed in non-karst forest trees.     

Calcium addition at the Hubbard Brook Experimental Forest increases sugar storage, antioxidant activity and cold tolerance in native red spruce (Picea rubens)

In fall (November 2005) and winter (February 2006), we collected current-year foliage of native red spruce (Picea rubens Sarg.) growing in a reference watershed and in a watershed treated in 1999 with wollastonite (CaSiO(3), a slow-release calcium source) to simulate preindustrial soil calcium concentrations (Ca-addition watershed) at the Hubbard Brook Experimental Forest (Thornton, NH). We analyzed nutrition, soluble sugar concentrations, ascorbate peroxidase (APX) activity and cold tolerance, to evaluate the basis of recent (2003) differences between watersheds in red spruce foliar winter injury. Foliar Ca and total sugar concentrations were significantly higher in trees in the Ca-addition watershed than in trees in the reference watershed during both fall (P=0.037 and 0.035, respectively) and winter (P=0.055 and 0.036, respectively). The Ca-addition treatment significantly increased foliar fructose and glucose concentrations in November (P=0.013 and 0.007, respectively) and foliar sucrose concentrations in winter (P=0.040). Foliar APX activity was similar in trees in both watersheds during fall (P=0.28), but higher in trees in the Ca-addition watershed during winter (P=0.063). Cold tolerance of foliage was significantly greater in trees in the Ca-addition watershed than in trees in the reference watershed (P<0.001). Our results suggest that low foliar sugar concentrations and APX activity, and reduced cold tolerance in trees in the reference watershed contributed to their high vulnerability to winter injury in 2003. Because the reference watershed reflects forest conditions in the region, the consequences of impaired physiological function caused by soil Ca depletion may have widespread implications for forest health.     

Seasonal biochemical changes in coniferous forest canopies and their response to fertilization

Seasonal changes in concentrations of total nitrogen, free amino acids, chlorophyll, starch and sugar were measured in foliage from fertilized and unfertilized conifer forests in New Mexico and Oregon. In the New Mexico Douglas-fir (Pseudotsuga menziesii var glauca (Beissn.) Franco) forest, fertilization resulted in elevated foliar nitrogen concentrations on all dates, from an average of 9 mg g(-1) in unfertilized trees to 14 mg g(-1) in fertilized trees. In the Oregon western hemlock (Tsuga heterophylla (Raf.) Sarg.) forest, fertilization increased total N by only 15%, from 13 mg g(-1) in unfertilized trees to 15 mg g(-1) in fertilized trees. Foliar nitrogen concentrations on a weight basis were lowest in winter and spring, but did not vary seasonally when expressed on a leaf area basis. Chlorophyll concentrations increased with fertilization and had greater seasonal variation than did total nitrogen concentrations. Chlorophyll concentrations were significantly higher during the growing season than in the winter and spring months. Fertilization did not result in major changes in the proportion of total nitrogen in chlorophyll at either the Oregon or the New Mexico site. Concentrations of free amino acids varied with date and fertilization treatment; in New Mexico, amino acids were highest in the winter sample, whereas in Oregon, they were lowest in winter and spring. At both sites, amino acid concentrations were significantly higher in fertilized trees than in control trees on most dates and the ratios of amino acid-N to total N were also significantly higher in fertilized trees. For both sites, starch concentrations were nearly zero for most of the year, but increased sharply just before bud break and initiation of new growth in the spring. Although fertilization resulted in increased nitrogen concentrations in foliage at both sites, the response in New Mexico was much greater than in Oregon. These results are in agreement with forest productivity data that suggest that growth in the New Mexico site is limited by nitrogen, whereas in the Oregon site it is not.     

Effects of nutrition spatial heterogeneity on root traits and carbon usage by roots of Cercis chinensis seedlings in split root rooms

In natural ecosystems, nutrition available for plants shows great spatial heterogeneity. Much is known about plant root responses to the spatial heterogeneity of nutrition, but little is known about carbon usage in roots in nutrition-deficient patches and its effect on root longevity. In this study, split-room boxes were used for culture of Cercis chinensis seedlings, and the small rooms were supplied with different nutrition levels. The number of the first-order roots in the rooms with nutrition supply was significantly higher than that in the rooms with deficient nutrition. Specific root length (SRL) of the first-order roots in the rooms with deficient nutrition reached its peak at day 64 after nutrition treatment. There was no significant SRL differences between the two order roots during the experiment. Biomass of the first-order roots in the rooms without nutrition supply was significantly less than that of the first-order roots in the rooms with nutrition supply from day 64 to 96. The total biomass of the lateral roots in the rooms without nu-trition supply decreased from day 64 to 96. The activities of the enzymes in roots in the rooms without nutrition supply increased and the activities of alkaline invertases in roots in the two sides of split box did not change significantly. The activities of the enzymes in roots in the rooms without nutrition supply increased gradually. These results suggest that nutrition spatial heterogeneity induced the changes in root traits and plants actively controlled carbon usage in roots in nutrition-deficient patches by regulating the activities of invertases and sucrose synthases, resulting in the reduction in carbon usage in the roots in nutrition-deficient patches.     

Vertebrate predation on Holm Oak,Quercus ilex,acorns in a fragmented habitat: effects on seedling recruitment

Rodent and avian consumption of Holm Oak, Quercus ilex, acorns were examined in central Spain during two high-production seasons, 1990–1991 and 1993–1994, in 1 and 3 large stands and in 6 and 10 small stands (0.2–12 ha) respectively, to study the effects of vertebrate predation on seedling recruitment. Previous data indicate that wood mouse abundance is much higher in small stands. Tree size, frequency of acorn-bearing oaks and acorn abundance were similar in the two sizes of forest stands. Overall acorn consumption was 33.7 times higher in the small stands compared to that in the large stands in 1991, and 3.1 times larger in 1994. Consumption of acorns by mice in the small stands was 49 and 95 times greater than that by birds in the first and second year, respectively. Seedling recruitment was significantly higher in the large stands in both study seasons. Regeneration by ramets was roughly similar in small and large stands in both seasons. Thus, predation by mice was apparently responsible for the failure of sexual reproduction in the small stands. The results suggest that vegetative regeneration might be the prevalent reproductive method of Holm Oaks in small forest tracts.     

桤木人工林细根与土壤养分含量季节动态变化

对桤木人工林细根、土壤养分含量的季节变化及其两者之间的关系进行了研究.结果表明:(1)桤木细根中大量元素N、Ca、K、Mg、P含量冬季高,春季最低;微量元素Fe、Mn、Zn、Cu、Pb、Ni、Cd含量冬季最低,春夏季较高.(2)土壤各层中大量元素N、Ca、K、Mg、P含量冬季最低,夏季最高;微量元素Mn、Zn含量在冬季最低,秋季最高;Fe、Ni、Pb、Cu、Cd含量在冬季最高,春秋较低.(3)细根和土壤中大量元素含量在冬季存在负相关关系,微量元素Fe、Ni、Cd含量在一年四季均存在显著负相关关系,Mn、Cu含量在春季、夏季和秋季存在负相关关系,Zn、Pb含量在春季、夏季和秋季存在正相关关系.     

澳大利亚辐射松遗传育种及其借鉴

澳大利亚辐射松遗传改良在过去的几十年中取得了较大的成绩, 其育种计划与育种策略在一定程度上反应了当前世界林木育种水平。较详细地介绍与分析了澳大利亚辐射松遗传改良的历程与成就, 供我国林木育种工作者参考。