ABT生根粉在杨树扦插育苗及落叶松移植育苗的试验报告

ＡＢＴ生根粉在杨树扦插育苗及落叶松移植育苗的试验报告关宝文（辽阳市灯塔县林业局）为提高苗木的产量与质量进行了应用生根粉试验。得知，杨树插穗用ＡＢＴＺ号５０ＰＰｍ处理３０ｍｉｎ扦插，成活率可提高到９４．５％；苗高、地径、根数、最长根生长量较对照高１６·...     

杨树黑膜覆盖扦插育苗试验初报

采用黑膜覆盖进行杨树扦插育苗试验,结果表明,黑膜覆盖能够明显提高苗木质量,显著降低育苗成本.与常规育苗对照相比,黑膜覆盖苗高平均高出46 cm,成活率提高8%,育苗成本节省53%.     

杨树地膜覆盖扦插育苗技术

对杨树采用覆膜育苗 ,能够增加苗床温度 ,提高苗木质量 ,使扦插育苗成活率达 98.3 % ,苗木生长好于未覆膜 ,每 667m2 可产合格苗 93 89株 , 级苗比率提高 1 5 .6% ;采用该技术育苗每 667m2 每年可比未覆膜育苗增加纯收入 3 83 .1元。     

杨树地膜覆盖扦撤育苗技术

对杨树采用覆膜育苗，能够增加苗床温度，提高苗木质量，使扦插育苗成活率达98.3%，苗木生长好于未覆膜，每667m^2可产合格苗9389株，Ⅰ级苗比率提高15.6%；采用该技术育苗每667m^2每年可比未覆膜育苗增加纯收入383.1元。     

美洲黑杨引种苗期试验初报

为了丰富当地杨树种质资源,从南京林业大学引种4个美洲黑杨无性系进行扦插育苗试验,结果表明：4个无性系中,895杨、797杨、95杨在当地均有良好的生长适宜性,其苗高分别为对照加拿大杨的124．3％、116．8％和114．2％,地径分别为对照加拿大杨的159．3％、136．5％和133．9％。关键词：美洲黑杨;引种;苗期试验;成活率;生长量     

杨树地膜覆盖法育苗技术试验

地膜覆盖育苗法有效提高了杨树育苗扦插成活率,延长了苗木生长周期,增加了生长量,提高了苗木质量,做到了当年育苗当年出圃,降低了育苗成本。     

杨树不同方法造林对比试验初报

通过对杨树不同方法造林试验，适当的造林方法不但可以提高造林成活率，而且可提高其生长量，用一年生扦插苗造林成活率比对照提高１２．２％；苗高和地径均比对照和其他造林方法有极显著的提高。     

思茅松扦插育苗技术研究

采用嵌套设计,设置扦插育苗环境、激素浓度和穗条木质化程度等3因素、2~5水平试验,对思茅松扦插育苗技术进行研究。结果表明:在野外小棚环境下,当ABT1生根粉浓度为1.0 g/L,以及利用半木质化穗条扦插时,扦插苗成活率均显著高于其他处理。当激素浓度为1.0 g/L时,思茅松扦插苗地径生长量较其他处理均极显著提高;利用半木质化穗条进行扦插能够极显著提高扦插苗苗高生长量,显著提高扦插苗地径生长量。野外小棚扦插苗表现为"粗壮",温室大棚表现为"细高"。     

良种沙棘嫩枝扦插容器育苗及造林试验研究

在全光雾嫩枝扦插育苗试验的基础上，采用网袋状轻型基质育苗容器进行容器育苗试验，结果表明，容器扦插平均生根率可达95％以上，较普通全光雾沙床扦插对照(CK)提高5．75％，主根数、虚根数均较对照(CK)增加1．02条，5．86条，平均苗高、地径分别增加4．33cm，0．07cm；容器扦插苗用于造林，其成活率较对照(CK)增加25．0％，当年株高、地径生长量较对照(CK)增加18．70cm，0．30cm；而且容器苗便于运输，可在整个生长季节随时移栽。     

滨海盐碱地柽柳扦插育苗试验报告

为选择合理的柽柳扦插育苗技术，在东营市中部和北部沿海地区进行了扦插育苗正交试验和对比试验。结果表明：插穗长度和粗度是影响扦插成活率和苗木生长量的主要因素，插穗长１５～２０ｃｍ、粗≥０．５０ｃｍ育苗效果较好。覆盖地膜可明显提高扦插育苗成活率和苗木生长量，且随土壤含盐量增加，效果越显著。同时，该文总结了用１年生扦插苗培养柽柳大苗的关键技术     

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.