印度紫檀等5树种在矿山迹地的生长表现

在矿山迹地上用印度紫檀、海南蒲桃、桃花心木、铁冬青、云南石梓等5种当地常用园林树种营造植被恢复试验林,研究各树种树高、地径、冠幅的生长情况及矿山迹地自然环境的变化.结果表明,海南蒲桃、桃花心木生长速度最快,而海南蒲桃、铁冬青景观效果最好,造林后林下植被种类丰富,生态状况改良效果明显.     

矿山迹地植被恢复树种选择技术研究

在矿山迹地上引种30多种阔叶树种,营造植被恢复试验林,通过生长比较,找出海南红豆、海南蒲桃等树种为适生树种。     

杉木林迹地不同树种更新的生态效应

根据杉木人工林连栽容易引起产量下降和地力衰退等问题,对杉木林采伐迹地采用火力楠、湿地松和马尾松进行更新对比试验,研究结果表明,以火力楠为更新树种形成的人工林生长快、蓄积量大,林下生物多样性丰富,土壤水分物理性质得到较大的改善,土壤肥力提高快。火力楠是杉木林采伐迹地更新较为理想的树种。     

6种阔叶树种在闽北的生长表现

文章以福建省建瓯市的6种阔叶人工纯林为研究对象,研究其不同时期的生长表现差异。结果表明:不同阔叶树种在早期(4 a)生长差异较大,其中,南酸枣早期生长最快,林分整体长势较好,枫香、闽粤栲、米槠和锥栗次之,而桤木的林木保存率较低,早期生长相对缓慢。而在造林17 a后,桤木和锥栗已经全部死亡,米槠和酸枣的林木死亡率接近1/3,而枫香和闽粤栲的林木保存率接近85%。同时,闽粤栲在4 a后的树高和胸径的年均生长量均显著高于其余树种,林分生长较好,枫香和米槠次之,相反的,南酸枣树高和胸径的年均生长量则最低,整体长势较差。     

茂名森林公园9种阔叶树种5年生长比较

通过引种9种阔叶树种种植比较试验,试验结果表明马占相思、大叶相思、海南红豆、海南蒲桃在该地方生长速度较大,是该地区营造生态林的优势树种。     

25种优良阔叶树种苗木生长节律研究

通过对吉安双江林场和南昌树木园3年来25个优良阔叶树种的育苗试验，充分表明了各树种育苗时在两地的物修及生长节律不尽相同，不同的树种在同一地点的生长节律有些树种的差异较大，有些树种的差异较小，对不同苗木的生长节律进行了初步的总结。     

忠县松材线虫采伐迹地生态恢复造林树种的选择研究

指出了忠县松材线虫除治和不断蔓延除治形成的采伐迹地的现状,探讨了在营造森林环境、恢复生态过程中,迹地条件下先锋树种的选择思路及办法。     

矿山迹地人工种植攀枝花苏铁试验简报

本文报道了在矿山迹地进行植被恢复特别是进行攀枝花苏铁恢复的技术操作.在矿山迹地进行大坑客土大苗造林,林草地表覆盖抗旱,优先恢复植被,再逐年恢复攀枝花苏铁,是矿山迹地攀枝花苏铁人工群落恢复的可行办法.     

红豆树等五种豆科珍稀树种种子及幼苗研究

我们在开展对珍稀树种的引种、栽培和推广应用时,就红豆树、软荚红豆、降香黄檀、格木、翅荚木等5种豆科珍稀树种培育出的幼苗进行观察、记载和绘制成图。并从种子(果实)到幼苗的整个发展过程,以及种子和苗木的生产技术做了细致的探索性地研究。以期为林业生产实践提供参考;为研究豆科植物系统发育和亲缘关系方面提供理论依据。     

Site influences herbicide efficiency and growth of planted hardwoods

Several herbicides (dalapon, 2,4-D, simazine, and diphenamid) were evaluated in response to their ability to promote height growth of black walnut, white ash, and yellow poplar through weed control when applied alone and in combinations on an upland and a bottomland site. Griwth benefits were highly dependent on the vegetation on the site. Dalapon and simazine were beneficial on the predominantly grassy upland for all three species whether applied alone or in combination. Simazine and 2,4-D alone or in mixture were beneficial on the bottomland, which contained mostly broadleaved weeds.     

Gas flow in hardwoods

Summary A model was developed for describing the axial gas flow through hardwood samples, and gas permeability variations with increasing specimen length. To that effect, the mean vessel length of the wood species () was taken into account, and the intervessel junction was modelled as a perforated plate. Mass and momentum conservation equations were then used to describe the fluid evolution through it. Outside the junction, wood was assumed to be a permeable material of Darcian behaviour. Thus, by combining Darcy's equations with the one derived for the junction zone, a system of equations was obtained modelling the overall fluid flow through the sample.The model was experimentally tested on ceibo (Erythrina crista-galli L.) samples of different lengths. Their gas permeabilities were measured, and the permeability of a zero-length sample (equivalent to that of an ideal specimen of infinitely long vessels) was calculated by means of an existing model. By introducing this last parameter into the above mentioned equation system, a theoretical value for the gas permeability was obtained. A fair agreement was observed between the model and experimental values, the differences between them being attributable to a number of simplifying assumptions that were made in order to render the system mathematically tractable.     

Silviculture of hardwoods in Great Britain

Many changes have occurred over the last 70 years: broadleavesno longer exceed conifers in area and coppice has declined markedly.While we see many neglected woods, especially on farms, thedepressingly poor quality of muchoak which Guillebaud lamentsis not now viewed so seriously. Today, broadleaves are grownfor a wider variety of objectives and not just for fine timber.While excellent stem form remains highly desirable, achievingit is notso critical where amenity, conservation or landscapeobjectives are uppermost. A major advance since Guillebaud's time is more rapid establishmentowing to herbicides and tree shelters though we still plantbroadleaves too far apart. Natural regeneration is again beingencouraged but we now have to add grey squirrels and muntjacdeer causing severe depredations besides the animals Guillebaudlisted. Broadleaves have a much more favourable press today becausethey are favoured for many more uses than simply timber production.This shift is the greatest contrast with 70 years ago and thegreatest influence on what silvicultural practices to adopt.     

Nursery and field establishment techniques to improve seedling growth of three Costa Rican hardwoods

Seedlings of three economically important and ecologicallydifferent native hardwoods, Cordia alliodora (Boraginaceae),Hyeronima alchorneoides (Euphorbiaceae), and Calophyllumbrasiliense (Clusiaceae), were grown in Rootrainers® (abook-type container), paper pots, and plastic bags filled witheither soil, soil with fertilizer, or compost substrates. Aftertransplanting in the field, treatments with and withoutfertilizer and herbicide were applied to all nursery stock types.In the nursery, species responded primarily to substrate type.Cordia grew better in bags of soil with NPK fertilizer andcompost than in unamended soil, probably responding to highernitrogen availability. Despite large treatment differences atplanting, there were no significant differences in plant sizeafter one year in the field between book containers and bags. Theexception were stump plants that were shorter and had highermortality. Hyeronima grew better in compost than in soil with orwithout fertilizer, probably responding to higher phosphorusavailability and lower bulk density of the compost. Plantsproduced in compost were also bigger after one year's fieldgrowth. Plants produced with soil or in paper pots had highermortality. Calophyllum grew less in compost compared to soil andgrew better when micronutrients were added to the compost andsoil. In the field, seedling produced in soil or withmicronutrients had higher survival or growth, respectively. Ingeneral, species grew better with herbicide and fertilizerapplication after transplanting. However, there were nointeractions with nursery treatments. Responses to fieldtreatments were independent and thus additive to the nurserytreatments. Differences in species response can be related tobiomass allocation patterns and ecology of the species.     

Studies on enzymatically liberated lignin in some Indian hardwoods

Summary Total effect of action of the wood-destroying fungusPolyporus palustris, belonging to the brown rot group, has been studied on mango (Mangifera indica) and chorapine (Hardwickia pinnata) woods, for various periods of attack at definite intervals and the lignin liberated was extracted. It was observed that the production of lignin was found to increase; if the fungus was allowed to attack for considerable periods and approximately 50 to 60% lignin was produced within two years.     

Penetration of hardwoods by liquids

Summary Oven dry highly evacuated sticks of the sapwood of various hardwoods, 40 cm long by 1.0 to 1.2 cm in the radial and tangential directions, took up water to the extent of 44 to 82% of saturation by capillary flow in one minute. Heartwood sticks took up 15 to 38% of saturation in one minute. The initial rapid penetration was followed by a penetration in which the take up increase directly with the square root of elapsed time. In this range, the slope of toluene take up plots was about twice that of the water take up. This is close to the theoratical value on the basis of viscous flow control. The linear portion of the plots is followed by a curvilinear decrease in rate of take up to a final equilibrium value. Water take ups approached 100% of the theoretical values.Times to 0.99 of theoretical filling with water varied from 9 minutes for tupelo gum sapwood to 14.6 to 17.3 days for white oak heartwood. Complete filling with toluene was never attained. Diffuse porous hardwoods filled to the extent of 93.5 to 96.5% of saturation. Ring porous oaks filled to the extent of 88 to 92%, the lower values being for heartwood. Edge coating of the sapwood of yellow poplar and yellow birch with epoxy glue reduced the rate of penetration only slightly. End coating reduced the rate to a higher degree. Moisture gradients in the fiber direction for tyloses-free hardwoods were negligible at various stages of penetration, indicating that filling of the vessels was practically instantaneous. White oak heartwood gave an initial longitudinal gradient followed by a negligible gradient, indicating that longitudinal penetration is primarily through the lumen of the fibers rather than continously through the vessels. Longitudinal penetration was calculated to be 31.5 times as deep as transverse penetration in 100 minutes and 33.3 times as deep in 25 minutes for white oak heartwood. The ratios are of the same order of magnitude as for Loblolly pine. In both cases the ratios are smaller than values calculated from the fiber dimensions alone as ray cell penetration and cross grain effects tend to lower the ratios.Paper No. 3947 of the Journal Series of North Carolina State University Agricultural Experiment Station, Raleigh, N. C.     

The marketing of British hardwoods

This paper considers the paper of the same name written by J.H. Newnham70 years ago, and then outlines the current situationand trends. The management of woodlands is a long-term process,but it is nevertheless disturbing to note that much of the broadleavedwoodland in Britain today is still suffering the same haphazardmanagement Newnham complained of, with high levels of under-managementand a poor growing stock. Newnham also regarded theforest industrywhich utilizes timber from British woodlands as not keepingupto date with new ideas and methods, and not giving consumersthe goods they actually require. There have been many significantadvances in softwood processing during the last 70 years, butthis level of innovation is not evident in the hardwood sector.The importance that we now place on the amenity and environmentalvalue of broadleaved woodland should not prevent managers fromgrowing at least some high-quality trees with a view to theirproviding a contribution towards the costs of management. Thiswill not happen unless there is a robust and concerted effortto manage deer and squirrels in broadleaved woodlands. New marketsfor some traditional products, developments in technology andthe willingness of people to network information may offer awider range of outlets to woodland owners in the future. Thefuture is viewed with some optimism; but so it was by Newnham.     

Observations of trabeculae in New Zealand hardwoods

Summary During a survey on the anatomy of New Zealand native woods, trabeculae were observed in the xylem cells of 6 hardwood species endemic to New Zealand. They were not found in a further 216 species. In some species they were observed only in the vessel members while in others they occurred in the vessel members, fibres and axial parenchyma cells. Their diameter is proportional to the thickness of the host cell wall. The similarites and differences between these trabeculae and those described as occurring in softwoods and other hardwoods are discussed. No explanation is proposed for their origin.We are indebted to the Conservators of Forests for Nelson and Westland, and to the Egmont, Abel Tasman, Urewera and Arthur's Pass National Park Boards for permission to collect wood samples; and also to Mr R. R. Exley, Physics and Engineering Laboratory D.S.I.R. for technical assistance.     

Maximum effective vessel diameters of hardwoods

Summary Measurements of the gas pressure required to displace water and allow gas bubbles to start continuously passing through the void structure of hardwood cross sections varying in thickness from 0.1 ... 10.0 cm have been used to calculate the maximum effective opening diameters. These diameters decrease with an increase in the thickness of the cross sections, as is the case for softwoods. Extrapolation of diameter—thickness plots to zero thickness gives the maximum vessel diameters, which agree well with microscopically determined values. The relatively small decrease in the maximum effective opening diameters with increasing thickness of the cross sections for most of the sapwood samples tested is due to irregularities in the vessel diameters and presence of perforation plates at the ends of the vessel segments. The decrease in the maximum effective opening diameter with an increase in the thickness of the cross sections is greater for the heartwood than for the sapwood. The ratio of the sapwood to the heartwood values tends to become constant between cross section thicknesses of 2.5 and 5.0 cm. This ratio was small for tyloses free northern red oak but appreciable for the hardwoods containing tyloses in the heartwood. Air drying followed by oven drying and resaturating of the specimens with water caused only small variable changes in the maximum effective opening diameters that were within the range of experimental accuracy of the measurements (approximately 5%).Paper No. 3616 of the Journal Series of North Carolina State University Agricultural Experiment Station, Raleigh, N. C.