福州国家森林公园绿量与生态效益

福州国家森林公园的森林绿量(叶面积)为847.6万m2,每天固定CO₂310t,放出氧气226t。可供福州市目前1/3,人口呼吸耗氧。       

濮阳市城市森林生态功能价值评估

在2006年濮阳市城市林业资源调查的基础上,借鉴有关评价森林生态效益的方法,选取对城市环境影响较大的6个方面,即吸收CO₂、释放O₂、净化环境、旅游休闲、野生动物保护和节能减排,初步估算出濮阳市城市森林生态功能效益年总价值约为29.51亿元。       

土壤与行道树的选择配置——以包头为例

土壤是影响行道树生长的重要环境因子。从土壤的物理化学特征如上层厚度、土壤容重和紧实度、土壤的水分供应、土壤有机质与养分含量、土壤酸碱度、土壤离子浓度等时论土壤对行道树成活及生长的影响,确定行道树的选择与配置。       

城市绿地综合生态效应场

本文以生态场理论为基础初步提出生物体与环境间相互作用产生空间综合生态效应场,这种生态效应场包括温度效应场、湿度效应场及CO₂效应场等。并选取哈尔滨市的两片典型绿地为研究对象,进行与人类舒适度密切相关的三种效应场(温度效应场、湿度效应场及CO₂效应场)的研究,指出了综合生态效应场存在的物质性及有限性。同时指出以产生场的主体绿地为中心的综合生态效应场为空间梯度场,场强由绿地中央至外围逐渐减弱,其减弱的程度各绿地间存在差异。       

广州地区“青山绿地”工程生态效益

研究了广州地区城市绿地系统森林植物-土壤系统生物同化、吸储、固定C,P,K,SO₂,Pb,Cd的生态效益,结果表明:研究区域内绿地系统土壤中有机C储量最高达184t/hm2,最低为24.6t/hm2;TN储量最高达16.7t/hm2,最低为2.0t/hm2;Pb,Cd储量最高分别达837.4kg/hm2、3.9kg/hm2,最低分别为577kg/hm2、1.2kg/hm2;植物叶对SO₂的积累量以高山榕最高,海芒果最低;小叶榕叶吸收固定Pb量最高为22.6g/hm2,尾叶桉叶和白玉兰叶吸收固定Cd量最高达0.15g/hm2。       

大夫山森林公园大气环境中污染物浓度变化及评价

利用长期定位观测方法对大夫山森林公园的大气质量进行监测,分析了大夫山森林公园大气污染源的种类、数量、分布规律,包括NO、NO₂、NO_x和SO₂浓度的日变化规律、季节变化规律进行了探讨。在此基础上,通过分析森林公园大气污染物超标率和分担率情况来评价大夫山森林公园大气质量的影响。结果表明,大夫山森林公园的大气质量非常良好,SO₂和NO_x秋冬季对大气环境有轻微污染,污染分担率最大的SO₂,其次是NO_x,而NO和NO₂对大夫山森林公园环境不产生影响。为进一步提高森林公园的大气环境质量,建议增加冬季常绿阔叶树种。       

西安城区植被净化大气污染物的时间变化

基于植被净化大气的机理,分析了净化量与污染物浓度、叶面指数等的关系,系统收集1991~2000年西安市TSP、SO₂、NO_X月均浓度,结合实验观察,得出:①西安市针叶林、阔叶林TSP、SO₂、NO_X净化量计算的经验公式。② TSP、SO₂、NO_X浓度在年内变化呈U字型,叶面指数年内变化呈倒U字型,二者变化不同步,植被对污染物净化量的年内变化整体也呈倒U字型。③ 1991~2000年TSP、SO₂、NO_X浓度的年际变化整体都是下降的,其中都有波动;10年来的植被覆盖率基本不变;植被对TSP、SO₂、NO_X的净化量与其浓度的年际变化同步,即成正比关系。       

我国首次碳汇交易在沈开盘——中日防沙治沙试验林在沈阳市康平县建设情况

在京都协议书规定的框架内,中日地方政府与民间相结合的碳汇交易,属于生态补偿性质的生态效益产品交易,开创了生态效益作为特殊商品的国际贸易先河。它不仅对生态价值理论探讨与实践研究具有学术价值而且对促进区域生态安全具有现实意义。此次交易达到了双赢。即发达国家冲减了CO₂排放额度,发展中国家可得到一笔资金补助,用于生态建设和改善农民生活。1999年沈阳市林业局和庆应大学开始合作,以建设"百里绿色长城"为题,在康平县营造防风固沙试验林。       

上海林地和绿地碳汇发展困境与对策

上海林地和绿地的土壤碳含量较低,固碳能力约为7.5万t/年。通过植树造林增加碳汇的潜力有限。建议通过加强森林抚育提高森林碳储量和碳密度;探索多元化的城市林业建设方式;因地制宜发展立体绿化,提高城市绿量;实施节约型园林绿化管理模式等措施来提高碳存储能力。       

城市绿化树种环境净化功能研究

文章研究了广州城市绿化树种生物同化、吸储、固定C,P,K,SO₂,Pb,Cd的环境净化功能,结果表明:研究区域内森林土壤中有机C储量最高达184 t/hm2,最低为24.6t/hm2;TN储量最高达16.7t/hm2,最低为2.0t/hm2;Pb,Cd储量最高分别达837.4kg/hm2、3.9kg/hm2,最低分别为577kg/hm2、1.2kg/hm2;植物叶对SO 2的积累量以高山榕最高,海芒果最低;小叶榕叶吸收固定Pb量最高为22.6g/hm2,尾叶桉叶和白玉兰叶吸收固定C d量最高达0.15g/hm2。       

Soil aeration and growth of forest trees (review article)

Many forest trees exhibit reduced growth or are killed when the soil is low in oxygen. Anaerobic soil conditions are associated with flooding or compaction of soil but also occur commonly in soils of heavy texture. Reductions in height growth, leaf growth, cambial growth and reproductive growth of trees growing on poorly aerated soils are well documented. The amount of growth reduction varies widely among species and duration of anaerobic soil conditions during the growing season. Inhibition of growth is preceded by changes in physiological processes, including food, water, hormone, and mineral relations. Some species can adapt to soil anaerobiosis by (1) producing hypertrophied lenticels which assist in aeration of the stem and release of toxic compounds, and (2) growing new roots to replace loss of original roots under anaerobic conditions. The replacement roots assist in absorption of water and mineral nutrients and in oxidizing the rhizosphere and detoxifying soil toxins. Ethylene, together with other compounds, appears to play an important causal role in morphological adaptations to soil anaerobiosis. Some forest trees can also adapt metabolically to poor soil aeration.     

Allocation of mass in trees subject to nitrogen and magnesium limitation

It has previously been shown that lack of magnesium, potassium or manganese depresses allocation of new mass to roots in trees, and that these elements often occur in low amounts in declining forest stands. A model for tree growth and nutrient uptake was used to examine the effect of allocation pattern of new plant mass on growth and development in soils with low nutrient concentrations. Growth parameters and empirical allocation functions from steady-state experiments with birch (Betula pendula Roth.) and Norway spruce (Picea abies (L.) Karst.) limited by N or Mg were used in the simulations. The simulation results show that plant nutrient concentration is sensitive to decreases in soil Mg concentration and is not counteracted by an increased allocation of plant mass to roots. A 50% reduction in the optimal soil Mg concentration decreased the plant Mg concentration to the threshold of survival, whereas a 50% reduction of soil N had much less effect. Birch was more sensitive to low soil Mg concentration than Norway spruce. We conclude that, in the discussion of forest decline, it may be important to consider the decreased allocation of mass to roots when Mg (or K or Mn) is in short supply.     

NITROGEN NUTRIENT MECHANISM IN SECONDARY SUCCESSION PROCESS OF THE MIXED BROAD-LEAVED/ KOREAN PINE (PINUS KORAIENSIS) FOREST

INTRODUCTlONThemixcdbroad-leaved/Pinuskor`IiensiSforestwhichisoneofthemainforestsofNortheastChina,isintlleCllangbaiMountail1s(JilinProvince)a11dtheXiaoxing'anMotu1-tains(inHeilonroIangProvince).Thisistl1empicalmixcddeciduous/co11iferforestvegcta-tionofthcarca.But,duetocuttingandanunbalancebctWeenharvesti11gandanntlalin-crement,themixedbroad-leaved/PinuSko-raiensIjforestsha1,ebeenreplacedwithsec-ondaryforests(includingthelargearPaofsecondaryforestleftfrol11thepast)sinceltsclearcutti…     

Nitrogen nutrient mechanism in secondary succession process of the mixed broad-leaved/Korean pine (Pinus koraiensis) forest

Chemical and biochemical analysis methods were used to monitor the variations of nitrogen nutrient among the dominance trees species in secondary succession process of the mixed broad -leaved/Korean pine forest on Changbai Mountains, Northeast China. Amounts of total nitrogen, ammonium and NRA in soils of virgin broad-leaved/Korean pine forest which is in climax were higher than those ofsecondary birch forests those are in succession stage. The amount of nitrate was in the other hand. In climax, dominance trees species are tolerant mesophytic trees such asPinus Koraiensis, Tilia amurensis, Acer mono and alsoFraxinus mandshurica, they are all ammonium + nitrate adapted species, but they show a preference for the ammonium rather than those of the pioneer trees species in secondary birch forest, such asPopulus davidiava andBetula platyphylla. Because they have more ammonium in their leaves and roots, especiallyPinus koraiensis. Populus davidvana andBetula platyphlla are intolerant trees, amounts of nitrate and total nitrogen is higher in their leaves and roots and also NRA in their leaves, so they preference for the nitrate rather than the others. In secondary birch forest, the regeneration trees species adapt their nitrogen nutrient to the variation of nitrogen nutrient situation in soil, finally they could survival well and the secondary birch forest would succession to climax. In climax, dominance trees species adapt their Nitrogen nutrient to the situation in soil and there are not strong competition in nitrogen nutrient among them, so they can coexist well and keep the climax as stable vegetation.     

Increased nitrogen-use efficiency of a short-rotation poplar plantation in elevated CO(2) concentration

We estimated nitrogen (N) use by trees of three poplar species exposed for 3 years to free air CO(2) enrichment (FACE) and determined whether the CO(2) treatment affected the future N availability of the plantation. Trees were harvested at the end of the first 3-year rotation and N concentration and content of woody tissues determined. Nitrogen uptake of fine roots and litter was measured throughout the first crop rotation. The results were related to previously published variations in soil N content during the same period. We estimated retranslocation from green leaves and processes determining N mobilization and immobilization, such as mineralization and nitrification, and N immobilization in litter and microbial biomass. In all species, elevated CO(2) concentration ([CO(2)]) significantly increased nitrogen-use efficiency (NUE; net primary productivity per unit of annual N uptake), decreased N concentration in most plant tissues, but did not significantly change cumulative N uptake by trees over the rotation. Total soil N was depleted more in elevated [CO(2)] than in ambient [CO(2)], although not significantly for all soil layers. The effect of elevated [CO(2)] was usually similar for all species, although differences among species were sometimes significant. During the first 3-year rotation, productivity of the plantation remained high in the elevated [CO(2)] treatment. However, we observed a potential reduction in N availability in response to elevated [CO(2)].     

环境因子对树木细根生物量、生产与周转的影响

细根在森林生态系统 C平衡和养分循环中的重要作用已为大量研究所证实。树木有赖于细根吸收水分和养分,而细根对环境胁迫比较敏感,因此细根动态可指示环境变化,还可反映树木的健康状态。影响树木细根生产和周转的因子很多,本文在收集大量研究文献基础上,讨论了土壤养分、水分、p H值、温度等环境因子以及大气 CO2 增长对树木细根分布、生物量、生产和周转的影响,以期为我国开展细根生态学研究提供参考。     

The North American long-term soil productivity experiment: Findings from the first decade of research

First decade findings on the impacts of organic matter removal and soil compaction are reported for the 26 oldest installations in the nation-wide network of long-term soil productivity sites. Complete removal of surface organic matter led to declines in soil C concentration to 20 cm depth and to reduced nutrient availability. The effect is attributed mainly to the loss of the forest floor. Soil C storage seemed undiminished, but could be explained by bulk density changes following disturbance and to decomposition inputs of organic C from roots remaining from the harvested forest. Biomass removal during harvesting had no influence on forest growth through 10 years. Soil compaction effects depended upon initial bulk density. Soils with densities greater than 1.4 Mg m⁻³ resisted compaction. Density recovery was slow, particularly on soils with frigid temperature regimes. Forest productivity response to soil compaction depended both on soil texture and the degree of understory competition. Production declined on compacted clay soils, increased on sands, and generally was unaffected if an understory was absent.     

森林细根生产和周转的影响因素

细根在森林生态系统碳平衡和养分循环中具有重要作用。随着全球碳循环研究的开展, 作为森林生态系统中土壤碳的主要来源, 对细根的研究受到了广泛关注。在系统分析国内外大量研究报道的基础上, 文中对影响细根生产和周转的非生物因素(土壤养分、温度、土壤水分及CO₂浓度)和生物因素(土壤生物、细根形态及林分特征)进行总结和评述, 分析根系研究中存在的问题, 对今后的研究方向提出展望。     

The Incidence of Root-Surface Fungi on Naturally Regenerated Picea sitchensis Seedlings in Southeast Alaska

The root-surface fungi were examined from naturally regeneratedSitka spruce obtained from recently exposed glacial outwashand mature upland soils where spruce had grown alone and inmixture with alder. Roots from the poorest trees on least fertilesoil had a high incidence of Mortierella and few other fungibut as growth and soils improved the numbers and genera of otherfungi increased The same genera occurred on roots from glacialdrift and upland soils and were the same as those found on intensivelygrown seedlings from acid heathland soil at Wareham forest nurseryin Dorest, England.     

Carbon budget of Pinus sylvestris saplings after four years of exposure to elevated atmospheric carbon dioxide concentration

To study the responses of Scots pine (Pinus sylvestris L.), a commercially important tree species in Europe, to future increases in atmospheric CO2 concentration ([CO2]), we grew saplings for 4 years in the ground in open-top chambers in ambient or ambient + 400 micromol mol(-1) CO2, without supplemental addition of nutrients and water. Carbon (C) budgets were developed for trees in both CO2 treatments based on productivity and biomass data obtained from destructive harvests at the end of the third and fourth years of treatment, and simulations of annual gross photosynthesis (P(tot)) and maintenance respiration by the model MAESTRA. Simulated P(tot) was enhanced by elevated [CO2], despite significant down-regulation of photosynthetic capacity. The subsequent increase in C uptake was allocated primarily to tissues with limited longevity (needles and fine roots), which explains why the measured annual increment in woody biomass did not differ between CO2 treatments. Thus, our results suggest that accelerated stem growth only occurs in the first 2 years in the presence of elevated [CO2] and that forest rotations will not be shortened significantly in response to increasing [CO2]. In elevated [CO2], a higher proportion of available C was allocated below ground, resulting in altered biomass distribution patterns. In trees of equal size, measured ratios of fine root/needle biomass and belowground/aboveground biomass were almost twice as large in the elevated [CO2] treatment. Although there are uncertainties in scaling from saplings to mature canopies, the data indicate that, in nutrient-limited Scots pine forests, elevated [CO2] is unlikely to accelerate tree growth significantly, but is likely to increase C inputs to soil.