楠木优树子代苗期性状遗传变异研究

利用60株楠木优树单系种子在政和国有林场开展楠木优树子代苗期遗传变异研究,对1年生苗木苗高的调查分析表明,苗高在不同家系间存在极显著差异,这种差异主要由遗传因素决定;1年生楠木优树子代苗木平均苗高为0.39 m,变幅为0.11~0.56 m;从参试家系中初步选择出14个优良家系,其平均苗高为0.51 m,平均遗传增益为30.39%,选择效果明显。     

江南油杉优树子代家系苗期遗传变异与早期选择

2013~2015年对38个江南油杉(Keteleeria cyclolepis)优树子代球果性状和苗期生长性状进行了调查和遗传变异分析,结果表明:1年生优树子代家系之间的生长性状的差异均达到了极显著水平,不同家系苗高为7.22~16.35 cm,地径为0.11~0.19 cm,苗木成活率为24.44%~85.87%,苗高和地径的家系遗传力均在0.80以上,其苗期的生长受遗传因素的影响较大;种子千粒重与子代苗木的成活率有着显著的正相关,果长和果径均与种子千粒重有着显著或极显著的正的相关性。通过综合分析,初步选出了6个苗期表现较好的家系,入选率为15.8%,其苗高、地径和成活率的平均值分别为13.96 cm、0.18 cm和59.50%,苗高遗传增益和地径遗传增益均值分别为16.54%和14.76%。     

桢楠优树半同胞家系苗期测定及优良家系选择

以30个桢楠优树的半同胞子代家系1.5 a生苗木为研究对象,测定苗高、地径和当年生新梢长度等生长量,分析各家系苗期的生长状况,初步筛选适宜四川复杂立地环境及气候条件的优良桢楠家系,为桢楠遗传改良及后期的良种选育提供参考。结果表明:苗高、地径、当年生新梢长等3个性状在家系间存在极显著差异,3个性状均受到强遗传控制,且3个性状间呈极显著正相关。综合考虑苗高、地径生长量,筛选出6个苗期生长较快的优良家系,其中崇州古寺2号家系表现最好。     

陈山红心杉优树自由授粉子代苗木生长特性研究

在四川省洪雅林场对陈山红心杉二代种子园的32个自由授粉优树子代进行苗期生长测定,结果表明:不同家系陈山红心杉的平均苗高为14.08 cm,平均变异系数为17.58%;平均地径为3.10 mm,平均变异系数为16.65%,家系间苗高和地径的差异均达到显著水平。苗高、地径的遗传力分别为0.866和0.889,表明其受到较强的遗传控制。通过综合评价,选出了3个优良家系,其平均苗高为16.31 cm,平均遗传增益为13.72%;平均地径为3.49 mm,平均遗传增益为11.18%,经选择的优良家系可进一步测定和评价。     

木麻黄抗风沙优树子代苗期生长遗传变异研究

通过对1年生木麻黄抗风沙优树子代苗的苗高统计分析,认为不同家系间苗高生长存在极显著差异,并通过分析发现这种差异主要受遗传因素控制,在遗传变异分析的基础上,选择出了在表型水平和遗传水平上表现优良的木麻黄家系66号和60号为优良家系,入选率为33%,入选家系平均苗高25.26 cm,遗传增益19.91%,选择效果明显。     

杉木第3代种子园半同胞家系子代苗期测定与优良家系选择

在四川省洪雅林场对来自福建省邵武市杉木第3代种子园的20个优树半同胞家系子代苗进行苗期生长测定,结果表明:2 a生杉木的平均苗高为14.72 cm,平均变异系数为20.30%,平均地径为3.11 mm,平均变异系数为20.91%,家系间苗高和地径的差异均达到显著水平。苗高、地径的遗传力分别为0.886和0.874,表明其受到较强的遗传控制。通过综合评价,选出了4个优良家系,其平均苗高为16.81 cm,平均遗传增益为11.00%;平均地径为3.47 mm,平均遗传增益为9.05%,可对入选的优良家系做进一步测定和评价。     

闽南红锥优树子代苗期遗传变异测定

对来自闽南的红锥24个初选优树子代和1个母树林子代进行苗期生长测定与遗传变异分析。结果表明:参试优树子代的苗高、地径遗传变异均较大,遗传力均较高。从种源变异看,来源华安金山林场和安溪的优树子代苗木生长量和遗传增益较高,1年生苗高、地径平均可达31.5~33.1cm和0.30~0.31 cm,苗高、地径遗传增益分别达8.16%~11.84%和9.24%~11.52%;从参试的优树子代中初步选出优良家系有华安2号、华安3号、华安4号、华安5号、华安6号、华安7号、池塘底A326和安溪A311、安溪A316和安溪A320,其中尤以来自华安的优良家系遗传增益最高,苗高、地径的遗传增益分别达17.30%~28.53%、13.56%~26.00%。初选出的10个优良家系苗木生长的增产效果较好,1年生平均苗高、地径分别可达32.0~40.0 cm和0.31~0.37 cm。     

米老排优树单亲子代苗期生长变异分析及选择

以福建上杭白砂国有林场选出12个米老排优树所培育的苗木为材料,研究其子代苗期生长表现,结果表明:12个米老排优树单亲子代苗木生长表现优良,优树胸径、树高、材积三者间和地径与苗高之间相关系数呈极显著正相关;子代苗期各性状遗传变异较大,地径、苗高、主根长、大于5cm侧根数差异均达显著和极显著水平,家系遗传力较高;以地径显著大于优树混合种为主要依据,采用多重比较初选9、7、3、6、8、5、4等7个优良家系,其平均地径、苗高分别达0.87cm、1.21m,遗传增益达4.9%、12.8%,比母树林良种提高了33.8%、101.6%。所选的7个优树可作为优良家系加以保护和利用。     

半枫荷12个优树家系子代苗期生长差异分析

对半枫荷Semiliquidambar cathayensis江西种源的12个优树家系1年生实生苗的苗高和地径生长量进行调查分析,从子代苗期测定方面进行半枫荷优树评价研究.结果表明:(1)半枫荷不同优树家系苗期的苗高、地径生长量差异均达极显著水平(P<0.01),其中,5号优树家系的苗高最大,为72.04 cm,高出苗...     

26个苦槠优树子代苗高生长量差异分析

分别从江西崇义、江西上犹、湖南汝城3个不同种源共采集26株苦槠（Castanopsis sclerophylla(Lindl.)Schott.）优树种子测定其千粒重,并进行子代苗期苗高生长调查试验,同时分析两者性状之间的相关性。结果表明：26个不同苦槠1a生优树子代苗高间生长表现出极显著差异水平,苗高总均值为29.53 cm,江西崇义14号优树子代苗高最大,达到51.10 cm,极显著大于其余各优树子代苗,其次是苗高为46.20 cm的江西上犹10号优树子代苗,江西崇义13号优树子代苗苗高最小,仅为12.50 cm,各优树子代苗高表型变异系数高达52.46%;不同种源苗高生长都有较好的反映,都呈逐步生长的趋势,并表现出明显的阶段性;种子千粒重与子代苗高之间无显著相关性,两性状间保持一定的独立性。     

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.