四个杨树无性系苗期能源林相关特性的研究

对1 a生杨树无性系能源林材性进行了比较分析.对4个无性系的生长量、生物量、木材基本密度、纤维素含量、C含量以及热值和灰分进行了测定.结果表明:杨树无性系的生长量年动态均符合"慢-快-慢"的S型生长规律.杨树无性系Y208的纤维素含量、C含量和热值较其他3个无性系高.     

5年生刺槐4个无性系的枝干生物量及热值对比分析

对河南省陕县5年生的3-I、豫刺槐1号、匈牙利四倍体、一般刺槐(CK)4个刺槐无性系的生物量、灰分含量、干质量热值和去灰分热值进行分析。结果表明:无性系间单位干质量热值和去灰分热值差异显著,分别在3750～3950kcal·kg-1与3800～4000kcal·kg-1之间,高低排序均为3-I>CK>豫刺槐1号>匈牙利四倍体;部位间单位干质量热值和去灰分热值差异显著,分别在3800～3960kcal·kg-1与3840～4000kcal·kg-1之间,高低排序均为树干中部>树枝>树干上部>树干下部;无性系间单株枝干干质量热值和去灰分热值差异显著,分别在10900～35000kcal与11000～35500kcal之间,无性系间单株枝干热值排序与枝干总生物量排序一致,均为豫刺槐1号>3-I>CK>匈牙利四倍体。综合热值、灰分含量和生物量分析,对刺槐进行能源林经营的品种选择是有效的,无性系豫刺槐1号选做能源刺槐树种栽培最为理想,3-I次之;树干中部为理想能量部位,树枝次之。     

不同光强对6个欧美杨无性系苗期生长及光合特性的影响

[目的]研究6个欧美杨无性系生长及光合特性对不同光强的响应差异,为欧美杨苗期快速选育高光效优良品种提供一定的理论依据。[方法]在大田用遮阴网设置CK(100%自然光强)、L1(55%自然光强)和L2(20%自然光强),测定欧美杨的苗高增长量、叶片形态、光合速率、叶绿素荧光特性、叶绿素含量及矿质元素含量。[结果]除11-26-9外,无性系的苗高总生长量随着光强的降低呈下降趋势;随着光强的降低,不同无性系的叶片形态变化趋势不一致,3个光强下无性系间的单叶面积、叶形指数和比叶面积存在差异;无性系在L2处理下的净光合速率(Pn)最低,胞间CO2浓度(Ci)最高;3个处理下,11-26-8的气孔导度均最大;在L1与L2下,11-26-9的F1/F0值均最大;无性系的叶绿素b含量与叶绿素总含量呈现相同的变化趋势;11-26-4、11-26-8和11-36-26的钾、钙、镁元素含量随着光强的降低而增加。[结论]不同无性系对光强变化的适应策略不同,部分无性系的高生长和净光合速率随着光强的降低而减小,降低光强没有破坏无性系的PSⅡ结构。多数无性系的总叶绿素含量、矿质元素含量随着光强的降低而升高。11-36-26无性系的生长势及抗弱光能力较弱。     

5个南方型杨树无性系苗木耐盐性盆栽试验

[目的]研究盐胁迫对杨树生长及生理指标的影响,开展不同杨树无性系耐盐性比较及评价。[方法]以895杨(Populus×euramericana‘Nanlin 895’)、1388杨(P.×euramericana‘Nanlin 1388’)、3804杨(P.deltoides‘Nanlin 3804’)、110杨(P.deltoides×P.cathayana cl.‘110’)和328杨(P.×euramericana cl.‘328’)5个杨树无性系为材料,采用室内盆栽方法,以无盐处理为对照,对其在不同盐(NaCl)浓度处理(1‰、2‰、3‰、4‰、5‰)土壤下的成活率、生长量、叶片细胞质膜透性、丙二醛含量、光合速率等13项指标进行测定和分析,采用隶属函数法对其耐盐性进行了综合评价。[结果]在土壤盐胁迫下5个杨树无性系的苗高、地径和生物量生长均受到了抑制;苗木成活率、叶片光合速率和叶绿素含量均随盐处理浓度的提高而降低;叶片细胞质膜透性和丙二醛含量随着盐处理浓度的提高而提高。[结论]5个杨树无性系耐盐性存在差异,其顺序为:110杨328杨3804杨895杨1388杨。110杨能耐受3‰左右的土壤含盐量,其它无性系只能耐受2‰左右。     

林分密度对桉树幼龄能源林的影响

对0.5年生3种不同密度配置的幼龄尾巨桉优良无性系DH32-29各器官生物量、热值以及灰分进行了调查和测定,结果表明:所选3种密度间树高差异显著,基径差异达到极显著水平,随着密度的增加,树枝、叶片、树干的生物量分别呈现减少趋势,密度与树枝和树干生物量的相关性达到了0.01极显著水平;单株生物量随密度的增大而减小,林分生物量则相反;单株热值无显著差异,仅单株平均灰分含量高密度与中密度存在显著差异。综合分析,高密度0.25 m×2 m林分生物量最大,其灰分含量比低密度的林分低,适合作为能源林培育密度。     

尾细桉等5种桉树无性系生物量和能量的比较研究

对广东廉江石岭林场尾细桉等5种7.5年生桉树无性系的生物量和能量进行了研究。结果表明:不同无性系各组分生物量的分布规律均以干的最大、叶的最小,枝、根、皮介于中间;5种桉树无性系各组分的生物量排序为:赤桉、尾细桉、巨尾桉为干根枝皮叶,雷林1号桉为干根皮枝叶,尾叶桉为干枝根皮叶。人工林生物量现存量的排列顺序为尾细桉(161.60 t.hm-2)巨尾桉(127.96 t.hm-2)尾叶桉(112.60 t.hm-2)赤桉(83.81 t.hm-2)雷林1号桉(71.36 t.hm-2)。各组分的灰分含量各不相同,以叶最高(4.08%~6.88%),干最低(0.17%~0.43%)。不同组分的干质量热值介于17.94~21.06 kJ.g-1间,去灰分热值介于18.57~22.12 kJ.g-1间,均以叶的值最高。植株体的平均干质量热值和去灰分热值分别为19.02~19.32、19.49~19.85 kJ.g-1,平均干质量热值的排序为雷林1号桉尾叶桉尾细桉赤桉巨尾桉,平均去灰分热值的排序为雷林1号桉赤桉尾叶桉尾细桉巨尾桉。5种桉树无性系林的能量现存量为1 360.73~3 067.47G J.hm-2,大小顺序为尾细桉巨尾桉尾叶桉赤桉雷林1号桉。综合生物量和能量现存量分析,尾细桉选作能源树种最为理想,巨尾桉和尾叶桉次之,赤桉与雷林1号桉最差。     

厚壁毛竹的主要化学成分及热值研究

对厚壁毛竹(Phyllostachys eduliscv.pachyloen)不同部位的主要成分和热值进行分析,结果表明:不同部位对其化学成分的影响均达差异显著性水平。灰分含量叶片最高,竹竿3/4部位最低,不同部位与厚壁毛竹灰分含量呈现类似开口朝上的抛物线的变化趋势;从地面到顶部冷水抽出物含量总体上趋于增加,而纤维素含量出现相逆的现象;苯醇抽提物含量除基部较高之外,其它部位的抽提物含量相差不大;1%NaOH抽出物含量高,平均值约为33.36%;综纤维素含量约57.75%,不同部位对其含量影响不明显。灰分与热值以及灰分与纤维素含量和综纤维素含量之间呈负相关,纤维素和综纤维素与热值呈正相关且有相同变化趋势,但均未达到显著水平。厚壁毛竹的热值与灰分、纤维素和综纤维素含量的回归方程为:Y=-4060.956+200.560X1+247.674X2+5.929X3。     

24种竹材炭化热值与工业分析

【目的】探究相同炭化工艺下不同竹种、竹龄和竹材不同部位等因素与竹炭热值之间的关系,分析竹炭热值与灰分、挥发分和固定碳含量之间的相关性,推导热值计算的经验公式,为竹材工业化和资源化利用提供参考和借鉴。【方法】选取浙江省杭州市临安区24种竹材以及安吉县2～13年生毛竹,在相同炭化工艺条件下烧制成炭,采用控制变量法测试24种竹材中部炭化料、2～13年生毛竹中部炭化料以及毛竹材不同竹龄(4、5、6年)和不同部位(梢部、中部和基部)炭化料的热值和工业分析参数,分析不同竹种、竹龄和竹材不同部位炭化料热值与固定碳、挥发分和灰分含量之间的关系。通过SPSS软件对热值与固定碳、挥发分和灰分含量之间的相关性进行鉴定和分析,根据竹炭热值与竹材炭化料固定碳含量和炭化温度之间的关系推导热值计算的经验公式。【结果】24种竹材竹炭热值为27.94～32.98 kJ·g~(-1),平均值为31.10 kJ·g~(-1),标准差为1.11,固定碳含量为75.35%～92.59%,平均值为85.87%,标准差为3.65,灰分含量为3.34%～15.98%,平均值为7.21%,挥发分含量平均值为6.91%; 2～13年生毛竹竹炭热值为30.93～33.81 kJ·g~(-1),固定碳、灰分和挥发分含量的标准差均在5以下; 4、5、6年竹龄毛竹炭化料各部位热值绝对差异在1.38 kJ·g~(-1)以内,相对差异在3%以内。竹炭的高位热值与固定碳含量呈正相关、与灰分含量呈负相关,通过试验以及整理归纳大量竹炭炭化温度与热值、理化性能的测试数据,推导出竹炭热值(Q)与其炭化温度(T)和相应的固定碳含量(C)之间换算的经验公式。【结论】1)不同竹种炭化料热值和工业分析参数存在显著差异,取决于不同竹种各自的结构特性,相同竹种炭化料,木质素含量较高的基部热值高于中部和梢部,竹龄和生长部位对热值和工业分析参数变化无明显影响; 2)竹材炭化料热值与固定碳、灰分含量之间呈线性关系,其中热值与固定碳含量呈显著正相关、与灰分含量呈显著负相关,热值(Q)与固定碳含量(C)的经验公式以及固定碳含量与其相对应炭化温度(T)的经验公式为Q=0.001 8C2-0.111C+28.099 (R~2=0.72)、C=26.934ln T-93.122(R~2=0.88)。     

金白杨6个无性系的抗寒性分析

为研究杨树抗寒性,以6个金白杨无性系为材料,测定了其半致死温度、丙二醛、可溶性蛋白、脯氨酸和超氧化物歧化酶含量,并对测定结果进行单因素方差分析与多重比较,建立了各无性系低温-电导率回归模型。结果显示,各无性系组织半致死温度在-23.8℃～-45.1℃之间;无性系间抗寒性差异极显著,C4抗寒性最好;各无性系抗寒性由大到小依次为C4A20K7C38C52C15.     

2种桉树不同林龄生物量与能量的研究

对广东廉江市石岭林场2种桉树不同林龄的生物量和能量进行了研究。结果表明:2种桉树各器官生物量及林分生物量都随林龄的增大而增大,各器官生物量都以干的最大,叶的最小。4.5年生雷林1号桉和尾巨桉林分生物量分别为77.13、80.03 t·hm^-2。不同器官间灰分含量、干质量热值、去灰分热值差异很大,排序分别为:皮>叶>根>枝>干,叶>枝或干>根>皮,叶>枝或根>干>皮。叶、枝、根、干的灰分含量随林龄的增大有减小的趋势,而干质量热值则相反;皮的灰分含量和干质量热值随林龄的变化与前者相反。植     

Browsing Damage on Pine (Pinus sylvestris and P. contorta) by a migrating moose (Alces alces) Population in Winter: Relation to Habitat Composition and Road Barriers

In Scandinavia, moose (Alces alces L.) sometimes cause severe browsing damage to economically-important pine. Moose-vehicle accidents have spurred construction of fences along roads, and these may interfere with moose migration between summer and winter ranges, or the road alone may be a barrier. If this happens and moose build up along roads, landowners may suffer economically. Therefore, this study investigated whether roads, fences or other factors influence the use of young pine stands by moose. Eighty stands along roads in northern Sweden were evaluated in which individually-browsed branches were counted on 9972 pines. Moose browsing was not significantly related to birch (Betula pendula Roth, B. pubescens Ehrh.) density, nor did it differ between pines (Pinus contorta Douglas or P. sylvestris L.). However, increased pine density, site productivity and proximity to a highway were associated with increased browsing. Further large-scale studies are needed to understand moose habitat selection and the effects of roads.     

Effects of Root Freezing on the Physiology and Growth of Picea glauca,Picea mariana and Pinus banksiana Seedlings Under Different Soil Moisture Regimes

The root systems of 2-yr-old Picea glauca, Picea mariana and Pinus banksiana seedlings were submitted to various frost temperatures during an artificial frost to induce different levels of root damage. Frost-damaged and control seedlings were placed in a greenhouse under high and low soil moisture regimes. Seedling growth and physiology were evaluated periodically. Seedling survival was reduced when root damage reached levels of 60-80%. Root systems of all three species showed partial to total recovery by the end of the experiment. In general, root freezing damage caused reductions in seedling growth, with these reductions becoming less significant over time. Root damage had little to no effect on black spruce and jack pine seedling physiology, while white spruce CO 2 uptake decreased with increasing root damage. Shoot nitrogen content of all three species decreased slightly with increasing root damage.     

Stand Structure in Pine,Spruce and Deciduous Forests: A Comparison Between Finnish and Russian Karelia

This study investigated the stand structure in pine, spruce and deciduous forests in the border district of Finland and Russia. A total of 46 mature forest stands was selected as pairs, the members of each pair being as similar as possible with respect to their forest site type, age, moisture and topography. The stands were then compared between the two countries by means of basal areas and number of stems. The proportions of dominating tree species were 2-12% lower, and correspondingly the proportions of secondary tree species higher, in Russian forests. The density of the forest stock was also higher in each forest type in Russia. The forests in the two countries differed most radically in terms of the abundance of dead trees. The amount was two to four times higher in Russian deciduous and spruce forests, and in pine forests the difference was 10-fold. The stand structures indicated that Russian coniferous stands, in particular, were more heterogeneous than intensively managed pine and spruce stands in Finland.     

Growth and Terminal Bud Formation in Picea abies Seedlings Grown with Alternating Diurnal Temperature and Different Light Qualities

The root collar diameter and the height:diameter ratio are of particular importance in container-grown seedlings where a high density in the containers may produce spindly seedlings. Temperature regimes and light quality are known to affect plant growth. The aim of this study was to identify responses in Picea abies (L.) Karst. seedlings grown with light providing different red:far-red ratios and under temperature regimes with alternating day (DT) and night temperature (NT) from negative (DT < NT) to positive (DT > NT) difference (DIF) between DT and NT. Experiments were conducted in controlled environment chambers and in a daylight phytotron. Only limited thermoperiodic responses appeared in P . abies seedlings with respect to seedling height and dry weight accumulation. The formation of terminal buds, however, was clearly delayed in seedlings grown at negative DIF. The results indicate a requirement for day extension light that is high in far-red, to prevent terminal bud formation under natural short-day conditions. An extended study should be conducted to clarify the minimum level of light intensity and the optimal light quality needed to prevent terminal bud formation under natural short-day conditions.     

CAD与建筑设计的关系

本文分析了CAD在设计中引起的正面和负面影响,并进行了系统的阐述,从而使设计者在应用中能够保持客观的态度。     

Natural Regeneration in Clear-cuts: Effects of Scarification,Slash Removal and Clear-cut Age

The effects of soil scarification (mounding), slash removal and clear-cut age on the natural regeneration in clear-cuts was evaluated using data from four sites in southern Sweden. The treatments were carried out during a good seed and establishment year for birch ( Betula pubescens Ehrh. and B. pendula Roth). Scarification had the strongest positive effect on the density of naturally regenerated seedlings, especially in birch, but also in pine ( Pinus sylvestris L.) and spruce [ Picea abies (L.) Karst]. Slash removal had a positive effect on birch density. No statistically significant effect of clear-cut age was found. In addition, no statistically significant interactions between clear-cut age and scarification or slash removal were found. The ingrowth of field vegetation was the fastest in areas that were not scarified, less rapid in areas scarified on old clear-cuts, and the slowest after scarification in fresh clear-cuts. In conclusion, it may be possible to control the density of birch during a good establishment year for birch. If birch is desired, the best combination of treatments is to remove the slash and scarify; otherwise, these treatments should be avoided.     

Risk Perception Among Non-industrial Private Forest Owners

Based on an enquiry, risk perception among non-industrial private forest owners is described in relation to climate change and forestry hazards. Of the respondents, 11% took action to remedy the effects of climate change. Out of a given set, hazards were ranked according to each respondent's experience of recent substantial financial loss to the estate and in relation to his or her willingness to make investments aimed at risk reduction. For each hazard, the respondent assessed the risk in four classes ranging from very high to negligible risk. Six hazards were considered most problematic in all three aspects: browsing damage, falling timber prices, damage by wind, spruce bark beetle, root rot and pine weevil. A majority of the respondents claimed to take action to reduce the risk associated with at least one hazard, while 35% did not know whether they did. Excluding climate change, the need for decision support was the largest in relation to damage by wind owing to a combination of perceived high risk and a high level of ignorance in relation to whether risk-reducing measures were taken.     

Interactions in decomposition and N mineralization between tropical legume residue components

In situ produced plant residues contain a mixture of different plant components of varying quality. To assess synergistic or antagonistic interactions occurring during the decomposition and mineralization of such mixtures, individual plant parts (stems, leaves, leaf litter and roots) or the mixture of stems, leaves and leaf litter of the agroforestry species pigeonpea (Cajanus cajan) or of crop residues of peanut (Arachis hypogaea) or of the weed hairy indigo (Indigofera hirsuta) were incubated in pots for 19 weeks. Periodically, remaining plant residues were sieved out (>2 mm), weighed and N content as well as soil mineral N determined. Above- and below-ground residues of peanut decomposed fastest and showed the largest N release in agreement with their high N concentration and low-acid detergent fibre (ADF) : N ratio. Hairy indigo was hypothesized to be of lower quality than pigeonpea because of its high-polyphenol content. However, it decomposed faster than pigeonpea, largely because of the higher N and lower lignin concentration of its components. Ranking of individual plant components for N mineralization resulted in the following pattern, leaves > leaf litter > roots > stems. In mixtures of the different plant components a similar species order in decomposition was obtained, e.g. peanut > hairy indigo > pigeonpea. The amount of N released from the mixture was dominated by stem material that comprised 46–61% of the mixture. The interactions in mixtures were relatively small for peanut (generally high-quality components) as well as for pigeonpea (low proportion of high-quality components, i.e. N rich leaf material). However, a positive interaction occurred during later stages of N mineralization in the mixture of hairy indigo as it had a significant proportion of N rich components and absence of highly reactive polyphenols. Thus, for plants with low to intermediate chemical quality attributes, manipulating plant composition (e.g. by varying harvest age, affecting stem and leaf proportions) will be important to obtain significant interactions during decomposition when its components are mixed.     

Pasture production and tree growth in a young pine plantation fertilized with inorganic fertilizers and milk sewage in northwestern Spain

The use of organic waste materials such as milk sewage as an organic fertilizer could have the dual advantages of organic-waste disposal and reduced dependence on inorganic fertilizers. The effects of fertilization with (1) conventional mineral fertilization, (2) milk sewage sludge at 40 kg N ha⁻¹ target rate and (3) no fertilization on pasture production and tree growth were examined in an experiment consisting of two pasture mixtures under a one-year-old Pinus radiata plantation with a density of 2500 trees ha⁻¹. The two pasture mixtures were: (1) Dactylis glomerata L. var. saborto (25 kg ha⁻¹) + Trifolium repens L. group Ladino (4 kg ha⁻¹) + Trifolium pratense L. var. Marino (1 kg ha⁻¹); (2) Lolium perenne L. var. Tove (25 kg ha⁻¹) + Trifolium repens L. group Ladino (4 kg ha⁻¹) + Trifolium pratense L. var. Marino (1 kg ha⁻¹). The experiment began in the spring of 1995 using a randomized block design with three replicates in Castro Riberas de Lea (Lugo, Galicia, north-western Spain). Plot size was 12 × 8 m², with a 1 m buffer strip between plots. Two-year data showed that fertilization with either material had a positive effect on pasture production, with no significant difference between the two fertilization treatments. Tree growth in the milk sewage sludge plot was significantly higher than in the control plots. Inorganic fertilization increased pasture production, but affected tree growth negatively. The results show that milk sewage sludge could be used as a fertilizer in silvo-pastoral systems. This revised version was published online in June 2006 with corrections to the Cover Date.