福建柏枝条扦插繁殖育苗技术研究

对福建柏枝条扦插繁殖育苗进行了技术研究,穗条采用2号ABT生根粉和吲哚丁酸不同植物激素溶液浸苗处理之后扦插。对穗条扦插生长的苗木进行了3年试验。结果显示:用2号ABT生根粉的植物激素浸种扦插的穗条生长状况,比用植物激素吲哚丁酸的植物激素浸种扦插的穗条生长状况好,成活率高6.1%,用2号ABT生根粉的植物激素浸种扦插的穗条根系生长伸展根系多、侧根长,苗木萌芽高度大、萌芽粗,分别比穗条用吲哚丁酸的植物激素浸种扦插的穗条生长的侧根长度增多20%、细根条数多27.3%、萌芽高度高5.8%、径粗大12.5%。     

青钱柳嫩枝扦插育苗技术研究

对青钱柳枝条采用ABT 1号生根粉和吲哚丁酸不同植物激素溶液处理。经过4年的扦插试验,枝条扦插之后,对苗木进行观察,采用不同的溶液对苗木进行浸种处理,其苗木生长状况不同。结果显示:用ABT1号生根粉处理的穗条比用植物激素吲哚丁酸处理的穗条,插穗成活率高11.2%,且根系生长伸展,侧根生长快、细根条数多、萌芽高又粗。研究表明,青钱柳嫩枝扦插,插穗宜采用ABT1号生根粉处理,效果较好。     

南洋杉侧枝扦插繁殖育苗技术试验

对南洋杉侧枝的穗条采用植物激素吲哚丁酸溶液和生根粉溶液浸苗扦插试验.论述了试验的相关材料选择和育苗技术方法,并对其进行调查分析.取得了重要试验数据:用吲哚丁酸溶液浸苗扦插繁殖的苗木平均成活率93%、苗木高33.5cm、地径粗0.28cm;用生根粉溶液浸苗扦插繁殖的苗木平均成活率95.5%、苗木高37cm、地径粗0.31cm.用生根粉溶液浸苗扦插繁殖培育的苗木成活率、苗木高,地径粗,比吲哚丁酸溶液浸苗扦插繁殖培育的苗木平均成活率高2.5%、苗木大10.5%、地径粗10.7%.     

红豆杉扦插育苗技术初探

通过对南方红豆杉、曼地亚红豆杉扦插苗和移床苗培育试验,探讨了插条来源、ABT生根粉、遮荫对红豆杉扦插苗成活和生长的影响。本试验的结论是:一年生苗干和多年生树冠外围枝条都能扦插成活,成活率达到70%~75%;扦插时用100 ppm浓度生根粉处理穗条效果较好;苗木移栽后采用30%透光率的遮荫可促进苗木生长。     

连香树种苗繁育和扦插培育试验研究

通过连香树种苗繁育和扦插培育试验,观察了连香树播种育苗当年生苗木生长情况,研究了不同时间扦插、不同部位枝条和不同粗度的穗条对连香树育苗成活率的影响。结果表明:7月~9月3个月为连香树苗一年中生长最为旺盛期;春夏季节扦插成活率好于秋冬季节;树木基部穗条扦插成活率明显好于树冠部位萌生的枝条;穗条粗度也是影响连香树扦插成活率的主要因素之一。     

提高马尾松扦插繁殖成活率研究

采用沙床和容器2种方法进行马尾松扦插繁育试验,选取珍珠岩、河沙及河沙+黄心土+草木灰混合进行不同基质扦插对比,在母树下部、中部及上部采集穗条扦插比较,生根剂不同浓度及处理方法进行扦插,研究表明:①以河沙、黄心土、草木灰混合或珍珠岩为基质进行容器扦插培育马尾松无性苗,其成活率和成苗率高,扦插苗生长快,起苗容易,苗木根系损伤小,造林成活率得到保证;②马尾松穗条扦插存在位置效应,母树中上部穗条与下部穗条扦插成活率差异显著,中上部穗条扦插成活率达90%以上;③用低浓度生根剂处理插条后蘸取含有相应浓度生根剂泥浆扦插,能大幅度提高马尾松穗条扦插成活率。     

铁观音茶叶不同育苗栽培技术实验

对铁观音茶叶苗木应用清水和植物激素吲哚丁酸溶液、生根粉溶液进行了不同处理,对扦插后的苗木和栽培的茶树生长状况进行了观察对比试验。试验结果表明:应用清水处理扦插生长的苗木高度25cm、地径粗0.23cm,栽培1年生长茶树高42cm;吲哚丁酸溶液处理扦插生长的苗木高度27cm、地径粗0.25cm,栽培1年生长茶树高48cm;生根粉溶液处理扦插生长的苗木高度29cm、地径粗0.26cm栽培1年生长茶树高52cm。应用生根粉溶液进行处理培育的苗木和栽培的茶树,比应用吲哚丁酸溶液和清水进行处理培育的苗木和栽培的茶树,分别苗高7.4%、苗粗4%、茶树大7.4%。径粗16%、13%、13%。     

杨树优质壮苗培育试验

采取选用不同部位的种条、不同粗度的插穗及不同的浸泡时间、扦插密度、不同施肥量与施肥种类等方法进行对比试验,通过对杨树苗木扦插成活率及生长指标的比较情况开展了杨树优质壮苗培育试验。结果显示:培育杨树优质壮苗应选择粗度在1~1.5cm的条材,剪穗应选择条材的中间段,扦插前浸泡3~5d,扦插密度以16.5万~18万株·hm~(-2)为宜;在苗木生长季节,施用基肥的同时,根据苗木大小应追肥2次。     

柳杉扦插育苗试验

用1号ABT生根粉不同浓度的溶液对不同长度的柳杉穗条浸泡30min后,进行9个不同的处理试验,以查明穗条长度和ABT生根粉处理的浓度对培育柳杉扦插苗的影响。试验结果表明,长度20cm的1～2年生穗条用150×10-6的1号ABT生根粉溶液浸泡30min,3～4月份进行扦插育苗,苗木的苗高和成活率最佳,苗高可达46 7cm,苗木成活率可达86 7%。     

长叶罗汉松扦插育苗试验

利用穗条长度、穗条在母树中的生长部位、6号ABT生根粉浓度以及扦插时间等13个不同处理进行长叶罗汉松扦插育苗试验表明,长度4～5cm的母树下部穗条用75×10-6的6号ABT生根粉溶液浸泡40min,3月份进行扦插的苗木成活率和苗高都最佳.     

Growth of Phlebiopsis gigantea in wood of seven conifer species

Heterobasidion parviporum and Heterobasidion annosum are widely distributed root‐rot fungi that infect conifers throughout Europe. Infection of conifer stumps by spores of these pathogens can be controlled by treating fresh stumps with a competing non‐pathogenic fungus, Phlebiopsis gigantea. In this study, growth of three Latvian strains of P. gigantea and the biological control agent ‘Rotstop’ strain was evaluated in stem pieces of Norway spruce, Scots pine, lodgepole pine, Douglas‐fir, Weymouth pine, Siberian larch and Sitka spruce. The growth rates of one H. parviporum and one H. annosum isolate were also measured in the same stem pieces. The growth rate of P. gigantea varied greatly in wood of different conifer species. It was higher in the three pine species, lower in Norway spruce and lowest in Sitka spruce and Siberian larch, and in Douglas‐fir, this fungus did not grow. The largest area of wood occupied by P. gigantea was in lodgepole pine. Growth of Latvian isolates of P. gigantea in the wood of Pinus and Picea species was comparable to that of the Rotstop isolate. Consequently, stump treatment with local P. gigantea isolates should be recommended. However, our results suggest that Douglas‐fir stump treatment against Heterobasidion by P. gigantea may be ineffective and other stump treatment methods should be considered.     

Growth of Mixed Birch-Coniferous Stands in Relation to Pure Coniferous Stands at Similar Sites in South-eastern Norway

Mean age, mean and top heights and yield were studied in 20 mixed stands of birch ( Betula pubescens Ehrh. and B. pendula Roth) and Picea abies (L.) Karst. and nine mixed stands of birch and Pinus sylvestris L. in south-eastern Norway. Each mixed stand and the adjacent pure coniferous stand (control) were growing under the same site conditions and had not been commercially thinned. There were no significant differences in mean age at breast height or in top heights between birch and conifers in the mixed stands, while mean height was significantly higher for birch than for spruce. A growth index was calculated based on total volume and age at breast height. For the spruce sites the growth in young mixed stands (birch < 17 m) was superior to that of pure spruce, while the difference was insignificant in older stands. The growth index correlated positively with the ratio between generatively and vegetatively regenerated birch trees, and negatively with the age of the oldest species in the mixture and with site quality. For the pine sites there was no significant difference in the growth index between mixed birch-pine and pure pine stands. A mixture effect of birch on the volume yield of spruce or pine could not be demonstrated.     

Defoliation by the Needle-shortening Pine Gall Midge,Thecodiplosis brachyntera,on Pines in Central Sweden

An outbreak of the needle-shortening pine gall midge, Thecodiplosis brachyntera , occurred on Scots pine, Pinus sylvestris (L.) and lodgepole pine, P. contorta (Dougl.) in central Sweden during 1995-1998. The larval feeding of T. brachyntera kills current-year needles and heavy infestation causes severe defoliation. A pattern of fluctuating defoliation among years and sites was found on both pine species. Defoliation was evenly distributed in the crown of P. sylvestris during years of high as well as low infestation; apical whorls had as much defoliation as basal whorls. In P. contorta , however, there was a tendency for defoliation to be concentrated on branches in the most apical whorls. Growth ring increments on P. sylvestris with high levels of defoliation (71%) did not differ from trees with moderate levels (26%) of defoliation. Shoot lengths were significantly shorter, however, on heavily infested trees the year after defoliation.     

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.     

Boron in forest trees and forest ecosystems

This review critically examines the role of boron (B) in forests in view of recent findings on B nutrition and the continuing occurrence of B deficiency. Many perceptions about the role of B in plants and its uptake and mobility have been altered since the last review on B in forest trees in 1990. Now there is evidence for a fundamental role of B in the formation of the pectic structure in primary cell walls in plants, and further roles in membrane function are being explored. In plants, channel-mediated B uptake, active B uptake and B uptake by mycorrhizas have been shown, B transporters have been identified, and B retranslocation has been shown. We explore these findings and their consequences on forest trees and on ecosystems that they dominate. Particular emphasis is placed on B retranslocation and B in mycorrhizal symbiosis, given their importance in trees.     

Development of Pinus sylvestris Main Stems Following Three Different Precommercial Thinning Methods in a Mixed Stand

Reducing competition by point cleaning may be an attractive alternative to conventional precommercial thinning in forestry. In this study, survival and development of main stems of Scots pine (Pinus sylvestris L.) following point cleaning were examined in a mixed stand of mainly Scots pine and birch (Betula pendula Roth and Betula pubescens Ehrh.) in northern Sweden. Treatments studied were: no precommercial thinning, conventional precommercial thinning, point cleaning of all secondary stems, and point cleaning of only the secondary stems that were higher than the main stem, within a radius of 0.8 m from the main stem, respectively. A randomised complete block design with three replicates was used. Measurements taken 13 growing seasons after these treatments showed that conventional precommercial thinning was the best treatment for retaining Scots pines as main stems. However, conventional precommercial thinning resulted in the poorest timber quality of the remaining Scots pines in terms of stem taper, thickest branch diameter and relative live crown height. In conclusion, point cleaning has to be followed by a complementary cleaning operation if the objective is to retain Scots pines as main stems in such mixed stands.     

Survival and Growth of Picea abies Regeneration after Shelterwood Removal with Single- and Double-grip Harvester Systems

Three stands in Sweden were followed for 7 yrs to study the survival and growth of Norway spruce [Picea abies (L.) Karst.] regeneration after shelterwood removal with single- and double-grip harvester systems. The height of all seedlings within circular plots was recorded before and after final cutting. The tallest seedling and one randomly selected seedling on each circular plot were permanently marked and their annual height growth was measured each year during the period 1993-1999. No significant differences between single- and double-grip harvester systems were found with respect to their effects on regeneration density, survival or annual height growth. The annual height growth of the individual seedlings after shelterwood removal was significantly correlated with seedling height before shelterwood removal. Significant differences were found in annual height growth between seedlings with high and low vitality. Logging damage did not affect the annual height growth. Several practical conclusions were drawn. First, the choice of harvester system does not affect seedling height growth or survival after shelterwood removal. Secondly, the removal of a 200 m³ shelterwood with 200 stems ha^-1 does not seem to constitute a serious problem for seedling survival and growth. Finally, estimated vitality and seedling height both seem to be fairly good predictors of postrelease survival and growth.     

Tree planting for dryland salinity control in Australia

Dryland salinity is emerging as a major form of land and water degradation in southern Australia, particularly in Western Australia, South Australia and Victoria, and to a lesser extent in New South Wales, Tasmania and Queensland.Tree planting, in combination with other vegetation treatments, is regarded as a leading solution to dryland salinity. Research has now shown that planting trees can significantly lower groundwater tables, and thereby reverse the causal process of salinisation. Substantial progress has been made towards answering the basic questions of which species to grow, how to plant, where to plant, at what density and configuration to plant, and how much area to plant. The economic potential for commercial tree planting has given impetus to partial reforestation in higher rainfall (> 600 mm yr^–1) areas. Even so, serious constraints are apparent, relating primarily to cost, uncertainty and attitude. The future should bring increasing community input and control, technical refinement and gradual adoption, provided all aspects of the issue are well researched, relevant information is well communicated and programmes are well administered. Some specific requirements for future research are identified in this review.     

Effect of Cuttings on the Scenic Beauty of a Tree Stand

The opinions of 207 respondents on the visual effects of seven different cutting types were asked using a nine-point verbal scale ranging from ''worsens very much'' to ''improves very much''. Other estimates were obtained by letting the same respondents evaluate photographs of stands which had been treated with different cuttings. The direct questions gave results quite similar to the evaluations of photographs for all but young respondents, indicating that most respondents were able to imagine the effect of the treatment correctly. The results based on the evaluation of photographs indicated that the effect of regenerative cuttings is negative while the impact of thinnings is positive. After a few years of cutting the stand is already regarded as clearly more pleasant than immediately after the cutting. Natural regeneration with seed trees seems to be a way to avoid the very negative immediate impact of clear-felling, especially in the case of Scots pine. Women, young, urban people and those who do not own forest or have work related to forests tended to experience thinnings less positively and saw regenerative cuttings as more harmful than the other test groups did.