闽南麻竹人工林地上部分现存生物量的研究

对闽南地区麻竹人工林地上部分生物量模型及现存生物量结构进行了研究。结果表明:以模型m=a·(D2H)b对麻竹地上部分总生物量和秆生物量进行估计较为可靠,而对枝、叶生物量的估计需引进枝下高因子h及模型m=a·Db·(H-h)C或m=a·Db·[(H-h)/h]C.闽南地区麻竹人工林地上部分平均现存生物量为39.518t·hm-2,按年龄分配为:3年生生物量最高,占59.17%,其次为2年生、4年生、5年生;按器官分配为:秆生物量最高,占62.81%,其次为枝、叶。地上部分总生物量与秆生物量随竹秆高度增加而递减,枝、叶生物量自6～8m区分段分别向秆基及秆梢递减。     

优良经济竹种红竹生物量的研究

对设置在安吉竹种园的红竹林试验样地进行了生物量测定。红竹1～5年生秆、枝和叶的平均含水率分别为50.4％、44.1％和53.8％。秆、枝和叶均以基部含水率最高,向上逐渐减小。其各自的生物量占地上部分总生物量以秆为最高(达70.3％～79.3％),叶最小(仅占6.5％～12.1％)。竹秆的生物量分布中心集中在秆基部,向梢部锐减,而枝和叶集中在分枝中部。地下部分生物量和竹林凋落物生物量占竹林总生物量分别为16.7％和8.9％。红竹林生物量地上和地下部分分配格式和疏林与灌丛生态系统相吻合。     

闽南麻竹人工林地上部分现存生物量的研究

对闽南地区麻竹人工林地上部分生物量模型及现存生物量结构进行了研究。结果表明:以模型m=a·(D²H)^b对麻竹地上部分总生物量和秆生物量进行估计较为可靠,而对枝、叶生物量的估计需引进枝下高因子h及模型m=a·D^b·(H-h)^C或m=a·D^b·[(H-h)/h]^C.闽南地区麻竹人工林地上部分平均现存生物量为39.518t·hm^-2,按年龄分配为:3年生生物量最高,占59.17%,其次为2年生、4年生、5年生;按器官分配为:秆生物量最高,占62.81%,其次为枝、叶。地上部分总生物量与秆生物量随竹秆高度增加而递减,枝、叶生物量自6～8m区分段分别向秆基及秆梢递减。     

长宁苦竹种群结构和地上生物量研究

本文研究了长宁苦竹的种群结构和地上部分生物量。结果表明：（1）人工经营和未经营的苦竹种群都为增长型种群，但人工经营苦竹种群落结构简单；（2）人工经营苦竹种群径级结构偏大；地上部分生物量较大；（3）在种群水平，长宁苦竹地上部分生物量为37．58t／hm^2，随径级增大而增大；（4）在构件水平，1a生苦竹的地上生物量为1074．20g／株，2a生的为2041．86g／株；（5）1a生苦竹竿、枝和叶的含水率普遍高于2a生。     

实心狭叶方竹种群的生物量结构与地下茎生长规律研究

依据Harper的构件生物结构理论和种群生态学方法,对实心狭叶方竹种群的生物量结构和地下茎生长规律进行了研究.结果表明:(1)实心狭叶方竹种群各构件单位的生物量配置为:秆(36.30%)>叶(21.13%)>枝(17.82%)>篼(13.43%)>鞭(10.18%)>根(1.14%).其中地上部分生物量占75.25%,主要集中在1～3龄;不同年龄地上部分各构件单位的生物量分配有较大差异.秆、枝、叶的含水率均以1年生新竹最高,并随年龄的增长而逐渐减小.(2)实心狭叶方竹秆基、秆柄和竹鞭等地下茎各构件较小;秆基和竹鞭上萌芽转化为壮芽的成功率较低;竹鞭主要生长在0～15 cm的土层,幼壮龄鞭有趋浅的动态,不利于其无性系种群的克隆生长,可能是导致其种源稀少的原因之一.     

海子坪天然毛竹无性系种群地上部分生物量结构研究

采用回归模型对海子坪天然毛竹无性系种群地上部分各构件单位生物量进行拟合为:W秆=2.867 7+0.007 3D2H、W枝=0.001 0D2H、W叶=-0.591 5+0.102 8D和地上部分总量W总=2.661 5+0.008 8D2H;秆、枝、叶的生物量分别占地上部分总生物量的88.48%、8.59%和2.93%;整个种群的生物量积累是随着年龄的增大含水率逐渐减小和生物量积累逐渐增多的过程.     

筇竹与黄皮树人工混交林中筇竹地上部分生物量模型构建

本研究以筇竹与黄皮树人工混交林中筇竹地上部分为研究对象,测定分析了1~4年生分株地上部分各构件生物量及含水率,建立人工筇竹分株地上部分各构件的生物量及总生物量模型,以期为人工筇竹林的经营管理及其碳汇项目的开发提供科学依据。结果表明：随着筇竹分株年龄的增加,各构件含水率和生物量均逐渐减少,筇竹1~4年生分株地上部分平均含水率分别为57.62%、53.40%、50.01%、42.66%,平均生物量分别为133.99、123.31、109.76、85.39 g/m²;各年龄分株地上部分生物量的分配均呈现出秆＞枝＞叶的变化规律。不同年龄分株的胸径与秆、枝、叶生物量及地上部分总生物量均有极显著相关性(P＜0.01)。以胸径为自变量建立的各年龄筇竹分株地上部分总生物量模型的决定系数(R²)均在0.93以上,具有较高的可信度,也有着较强的适用性,可用于类似立地条件下的筇竹分株生物量估测。     

毛竹人工林生物量结构变化研究

对会同县经营10年的毛竹人工林林分生物量结构变化进行研究,结果表明:人工竹林不同龄级、径级、枝下高级和不同密度的生物量分配,81.2%生物量分配于1~7年生幼龄、壮龄、中龄竹;83.4%生物量分配于胸径11~15 cm之内;90.7%的生物量分配于枝下高7~11 m之内;86.2%生物量分配于立竹4 500~9 000株/hm2的林分之内,其中立竹4 500~6 750株/hm2的中密度林分,群体和个体生物量都表现出较高的水平。试验竹林垂直总生物量和地上、地下生物量比对照竹林分别增多1.81倍和1.97倍、1.56倍,地上与地下生物量之比为1.774∶1,经济系数为0.501,生物量从大到小的排序,地上部分为秆﹥枝﹥叶﹥凋落物﹥竹箨﹥退笋,地下部分为鞕根﹥竹鞕﹥竹蔸﹥竹根﹥死鞕。     

巴郎山川滇高山栎灌丛地上生物量及其对海拔梯度的响应

采用标准地和样方收获法,对卧龙自然保护区5个海拔高度上18个样地的川滇高山栎灌丛生物量进行调查.结果表明:1)用地径(D)、树高(H)估测单株木各器官生物量的适合模型为指数模型和幂函数模型,指数模型最佳,相关系数0.941～0.998;而用D2H估测单株木各器官生物量的适合模型为直线和指数模型,直线模型最佳,相关系数0.982～0.996;2)川滇高山栎灌丛群落地上部分总生物量为25.22 t·hm-2,各层生物量排序为川滇高山栎灌木层＞枯枝落叶层＞伴生灌木＞苔藓层＞草本层,其生物量占总生物量的百分率分别为72.20%、23.71%、1.80%、1.66%和0.63%;3)川滇高山栎灌木种群平均总生物量为18.21 t·hm-2,各器官生物量大小为干＞枝＞叶＞皮,分别占总生物量的43.28%、26.88%、19.82%和10.02%.海拔2 720～2 920 m地带川滇高山栎灌木干、枝、叶、皮的生物量比例约为4:3:2:1;海拔3 020～3 120 m地带川滇高山栎灌木干、枝、叶、皮的生物量比例约为4:2:2:1.4)随着海拔升高,川滇高山栎优势单株地径、高度及生物量呈减小趋势.海拔2 720～2 920 m处,川滇高山栎灌木地上部分各器官生物量呈纺锤形分布,集中分布在株干高2.0～3.0 m处,约占总量的60%～70%;在海拔3 020～3120 m处或低海拔的干旱生境,川滇高山栎种群地上部分器官生物量呈金字塔形分布,个体地上部分生物量分布随树干的升高而降低,集中分布在0～1.0 m处,占总生物量的60%以上,0.0～2.0 m处的生物量占总生物量的94%～99%.     

苦竹在炼山后生长恢复情况调查研究

研究杉木林下的苦竹,在杉木采伐、炼山后的恢复生长情况.研究表明苦竹具有很强的生长能力,在无人工促进情况下,前两年新竹的平均直径分别为0.47 cm、0.58 cm,平均高度为54.7 cm、109.3cm,新竹数量16.7株·m-2、9.4株·m-2,郁闭度为0.33、1.0;地上部生物量为965 g·m-2、1 071g·m-2,其中叶片的生长量较秆、茎大,约占地上部生物量的一半.前两年间的生物量无显著差异.     

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.