杉木与米老排等阔叶树混交林的水源涵养功能

对福建省尤溪县西城镇玉池至音头村之间公路沿线一重山营造的杉木分别与米老排、木荷、火力楠、闽粤栲行间混交林分水源涵养能力进行研究。结果表明:各林分地上部分持水量主要集中在林冠层,占林分地上部分持水量的71.2%~85.7%;林分总持水量主要集中在土壤层,0~40 cm土层持水量占林分总持水量的99%以上。依据林分总贮水量的大小,4种类型林分的水源涵养功能大小依次为杉木-闽粤栲>杉木-米老排>杉木-木荷>杉木-火力楠。     

漳州市主要速生树种林分生物多样性及碳汇能力比较

应用"模式森林经营体系研究"的调查资料,分析了巨尾桉、杉木、马尾松纯林以及杉木与巨尾桉、火力楠、米老排、马尾松混交等几种闽南地区常见的速生林分类型生物多样性和碳汇能力,结果表明:巨尾桉纯林、杉木×巨尾桉混交林林下植被丰富,碳汇能力强,年净吸收CO2量分别达33.51和27.59 t.hm-2,是很好的有利于生物多样性保护的工业原料林和碳汇林;杉木与火力楠、米老排、马尾松等混交林及集约经营杉木林碳汇能力也较强,是较好的速生用材林和碳汇林;杉木×马尾松混交林生物多样性低的问题可以通过营林措施改善。     

桉树人工林的水源涵养功能

以不同林分类型各层次的持水能力及林地土壤持水能力为依据,评价各林分水源涵养能力。结果表明:不同林分类型的水源涵养能力存在差异,其中地上部分持水能力以次生林最佳,为30.6t·hm-2;林分最大持水量和林分持水量以马尾松林最佳,分别为2166.5和2290.9t·hm-2,尾巨桉林均居中等水平,说明尾巨桉林与乡土树种林的持水能力都比较强。据此可以推测,随尾巨桉林龄的增加,其地上部分的持水能力会逐步增强。     

马尾松混交林土壤持水性和肥力特征

通过马尾松与格氏栲、青栲、火力楠及杉木等树种混交试验,13年生时测定不同混交林土壤的持水性、土壤结构和养分。结果表明,马尾松格氏栲和马尾松青栲混交林土壤饱和持水量大于马尾松火力楠和马尾松杉木混交林,土壤结构破坏率以马尾松格氏栲和马尾松青栲混交林较低,而马尾松格氏栲混交林土壤孔隙度最大,且马尾松格氏栲和马尾松青栲混交林土壤有机质、全量养分和速效性养分含量高于其他2种混交组合。格氏栲和青栲为马尾松伴生树种可以促进林分涵养水源,提高土壤肥力。     

马尾松火力楠混交林生物量及水源特征研究

对马尾松火力楠行状混交林、马尾松纯林及火力楠纯林乔木层生物量、地上部分持水量、土壤渗透性能及贮水能力对比研究,结果表明,马尾松火力楠混交林生物量大于马尾松纯林和火力楠纯林,混交林地上部分持水量大,土壤渗透性和贮水能力强,其综合水源涵养力强于马尾松纯林和火力楠纯林。     

尾巨桉与杉木林地土壤物理性质对比研究

对成熟期的11年生尾巨桉林和23年生杉木林的土壤物理性质进行分析比较,结果表明,相对于杉木,种植尾巨桉后,尾巨桉林地0~60cm各层次土壤容重、自然含水量均较小,0~60cm各层次土壤总孔隙度、非毛管孔隙度、最大持水量、毛管持水量及田间持水量均较大,林地土壤变得较为疏松,改善了土壤的透气状况和透水性,但土壤变得较为干燥,土壤表层沙化,粘粒下移。经方差分析,尾巨桉林和杉木林间土壤非毛管孔隙度、最大持水量差异显著。     

马尾松混交林持水性能的研究

通过对南方陡坡山地开展马尾松不同混交林林分类型持水能力研究,结果表明,马尾松与阔叶树木荷、火力楠混交,林分持水能力比马尾松与杉木混交及马尾松纯林强,针阔混交林能较大提高土壤涵养水源和保持水土的能力,使土壤得到较好改良,而营造针叶林则土壤持水能力低,易发生水土流失。建议南方陡坡山地采用针阔混交造林,尽量避免针叶纯林。     

马尾松多树种混交林水文效应和土壤性质研究

采用马尾松木荷台湾相思按2∶7∶1和4∶5∶1混交及马尾松火力楠杉木按1∶5∶4和5∶4∶1造林,19年生时研究其水文特征和土壤肥力状况。结果表明,马尾松木荷相思混交林持水能力高于马尾松火力楠杉木混交林,其中按2∶7∶1配比的马尾松木荷相思混交林其持水量最大,比按1∶5∶4配比的马尾松火力楠杉木混交林大19.43%,比...     

杉木与不同阔叶树种混交生长效应分析

为研究杉木阔叶混交林的生长效应,以33年生纯杉木林、7杉木3火力楠混交林和7杉木3米老排混交林3种林分为研究对象,比较分析杉木与不同阔叶树种混交的生长效果。结果表明：火力楠和米老排分别与杉木混交造林能够提升杉木生长量与蓄积量,与纯杉木造林比较,平均胸径分别提高了7.07%和12.44%。杉阔混交造林对杉木大径材培育具有促进作用,其中米老排的效果更佳。     

马尾松多树种混交林水文效应和土壤性质研究

采用马尾松、木荷、台湾相思按2∶7∶1和4∶5∶1两种比例混交及马尾松、火力楠、杉木按1∶5∶4和5∶4∶1两种比例造林,19年生时研究其水文特征和土壤肥力状况。结果表明:马尾松、木荷、相思混交林持水能力高于马尾松、火力楠、杉木混交林,其中按2∶7∶1配比的马尾松、木荷、相思混交林其持水量最大,比按1∶5∶4配比的马尾松、火力楠、杉木混交林大19.43%,比按5∶4∶1配比的马尾松、火力楠、杉木混交林大24.43%;马尾松、木荷、相思混交林土壤肥力状况优于马尾松、火力楠、杉木混交林;马尾松、木荷、相思混交林具有更强的持水固土改土能力。     

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。     

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.     

Key Habitats in the Norwegian Production Forest: A Case Study

This study investigated the forest history, structural characteristics, the presence of fungal species suggested to indicate ecological continuity in old-growth forest, and the species composition of saproxylic beetles in 30 old forest ''woodland key habitats'' (WKHs), and compared them with production forest in the same age-class in south-eastern Norway. No statistically significant differences in forest characteristics, community of saproxylic beetles or number of red-listed beetles were found between the WKHs and the production forest, probably owing to a combination of profound long-term logging and a lack of will to delineate sufficiently large WKHs in the one area with significantly less forestry impact. The study indicates the advantage of including forest history information in WKH selection where such data exist, and the importance of restoring habitats in heavily exploited forest landscapes.