Nitrogen Transformations and Decomposition in Litter and Humus from beneath Closed-Canopy Sitka Spruce

Samples of litter and humus from beneath 10 m tall, closed-canopySitka spruce planted on a brown forest soil were incubated underboth field and laboratory conditions to measure mineral nitrogenproduction and carbon dioxide evolution. Mineral nitrogen productionin enclosed samples over 12 months was equivalent to 50 and17 kg N ha^–1 in litter and humus, respectively. Applicationsof fertilizer NPK (200 kg N ha^–1 as ammonium nitrate,100 kg P ha^–1 as unground rock phosphate and 150 kg Kha^–1 as potassium chloride), 18 months previously, decreasedthese values slightly, but stimulated the production of nitratein both litter and humus. Compared with samples kept under laboratoryconditions at 10°C, those incubated in the field at a similarmean temperature released less carbon dioxide and, in the caseof fertilized humus produced smaller amounts of mineral nitrogen.     

Some Effects of Afforestation with Lodgepole Pine on Rates of Nitrogen Mineralization in Peat

Rates of mineral nitrogen production and carbon dioxide evolutionin incubated samples from the upper 300mm of peat beneath lodgepolepine (Pinus contorta Dougl.) have been compared with those foradjacent unplanted areas at each of six sites in the North ofScotland. Under both aerobic (moist) and anaerobic (water logged)conditions, rates of mineral nitrogen production at 30°Care strongly influenced by peatland type, sampling depth andafforestation. During the early stages of the incubation underaerobic conditions, samples of planted peat showed a more rapidaccumulation of mineral nitrogen than did samples from unplantedareas, the amounts after 17 days being 170ppm and 46ppm mineralN, respectively; after 62 days however, the difference was nolonger significant. The mean rate of CO₂ production averaged446µg CO₂ g^–1 day^–1 in planted as against728µg in unplanted peat. Under anaerobic conditions, amountsof mineral nitrogen accumulated were similar in planted andunplanted sites but a difference in accumulation between the0–150 and 150–300mm horizons in unplanted peat wassignificantly reduced beneath the trees.     

Feeding in the Crowns of Scots Pine Trees by the Pine Weevil Hylobius abietis

Hylobius abietis (L.) (Coleoptera:Curculionidae) is the major insect pest of forest regeneration in Europe, where adult weevils kill conifer seedlings by feeding on the bark. This study demonstrates that pine weevils also feed extensively in the crowns of mature coniferous trees. Crown feeding primarily took place during a limited period immediately after the migration to new breeding sites (roots of freshly cut coniferous trees). The weevils reached the crowns mainly by flight and tended to concentrate on trees in freshly cut-over areas. The proportion of sexually mature females successively increased during the crown-feeding period, indicating that they require a certain period of maturation feeding. The pine weevils fed on twigs of 3-20 mm thickness, and they consumed about 0.2-0.3% (200 cm²) of the total bark surface in the crowns of mature Scots pine trees. Calculations suggested that the amount of food consumed in the trees surrounding a fresh clear-cutting should have met the nutrient requirements of the weevil population in the area during the maturation feeding period. In the crowns of shelterwood trees, about 50 cm² of the bark was consumed per tree (0.63 m² ha-1). This level of consumption is not believed to be high enough to relieve the feeding pressure on seedlings and thereby explain the low level of damage usually found under shelterwoods.     

杉木与固氮树种混交对土壤有机质及氮含量的影响

采用两室根箱混交栽培试验方法,以台湾桤木(Alnus formosana)、大叶相思(Acacia auriculaeformis)、杨梅(Myrica rubra)和刺槐(Robinia pseudoacacia)4种固氮树种作为伴生树种,以纯杉木(Cunninghamia lanceolata)作为对照,研究杉木与固氮树种的混交栽培对土壤有机质与氮含量及其空间分布的影响。结果表明,与纯杉木比较,混交模式有效地提高根际区和非根际区的土壤有机质含量、全氮含量以及有效氮含量。5种栽培模式的根际区土壤有机质含量、全氮含量和有效氮含量均显著地高于非根际区的;根际区内0~2、2~4 mm两个土层的土壤有效氮含量之间的差异不明显,非根际区内0.4~2、2~4、4~5 cm等3个土层的土壤有效氮含量之间具有显著差异,总体表现为距离根垫越远,土壤有效氮含量越低。     

Variation in Stemwood Nutrient Concentrations in Scots Pine Growing on Peatland

Radial and longitudinal variation in the nutrient concentrations of Scots pine (Pinus sylvestris L.) stemwood and the effect of fertilization (PK and NPK) were studied on three peatland sites in eastern Finland. The results showed distinctive patterns in longitudinal and radial nutrient concentrations in stemwood. The N, P and K concentrations were highest in the youngest tissues both in the radial and longitudinal directions independent of the site type or fertilization. Ca and Mn accumulated in the older parts of stemwood. Increased N, P, K and Ca concentrations were found 9 yrs after fertilization in the annual rings formed during the first-5-yr period after fertilization. Decreased Mn concentrations were found in the annual rings formed during the 5-and-9-yr periods after fertilization. The results indicate that in the intensive utilization of Scots pine stemwood, e.g. whole stem harvesting instead of stem harvesting to a fixed diameter (7-8 cm in Finland), nutrient loss increases proportionally more than the amount of harvested biomass. The results also imply that this wood contains more undesirable elements, such as K, which may cause problems in wood combustion in power plants, and that fertilization raises these concentrations in wood. However, the concentrations in unfertilized trees were generally at about the same level as in Scots pine stemwood grown on infertile mineral soil sites.     

Canopy Structure and Leaf Area Index in a Mature Scots Pine Forest

The projected leaf area index (LAI) of a mature stand of Scotspine (Pinus sylvestris L.) at Thetford Forest, south-east Englandwas measured by sampling the needle populations on harvestedand wind-thrown trees covering the range of girth sizes. Thevertical distribution of leaf area for individual trees waspolymodal while that for the canopy as a whole was adequatelydescribed by the curve for a normal distribution with the inclusionof a term for positive skewness. The fitted curve defined themidpoint of the canopy at a height of 14.3 m and the standarddeviation of leaf area with respect to height as 13% of thecanopy depth. The fitted curve explained 90 per cent of thevariation and the estimates of the parameters were close tothe measured values. Using previous measurements showing that needle production andfall could be described by linear regression equations, a modelwas developed to predict the annual changes of current and oldneedles in a closed canopy. The maximum LAI at Thetford was2.73 on 12th August of which 36 per cent was new (current) needles.Leaf area index varied by only 7 per cent between November toMay inclusive; higher values occurred between June and Octoberat times of potentially high photosynthetic and transpirationrates. The leaf characteristics of the stand were similar to thoseof a stand of Scots pine of similar age at Roseisle in north-eastScotland.     

山西太岳山典型森林群落土壤有机质及氮素研究

分析了太岳山7种典型森林群落土壤有机质和氮素的基本状况,结果表明:不同林型,土壤腐殖质层和淀积层有机质含量均是油松辽东栎混交林最高,分别为4.908g/kg和3.528g/kg;土壤腐殖质层有机质含量油松林最低,为3.959g/kg,淀积层有机质含量山杨林最低,为1.779g/kg;土壤腐殖质层全氮含量,白桦林最高,为0.368%,辽东栎林最低,为0.176%。;土壤腐殖质层速效氮含量华北落叶松林最高,为292.191mg/kg,油松林最低,为167.725mg/kg;土壤淀积层全氮含量油松林最高,为0.277%,油松辽东栎混交林最低,为0.094%;土壤淀积层速效氮含量山杨林最高为200.183mg/kg,油松辽东栎混交林最低,为49.151mg/kg;土壤有机质、全氮及速效氮含量均是上层土壤高于下层。腐殖质层和淀积层土壤有机质含量在各林型间差异均不显著(P>0.05),而全氮和速效氮含量在各林型间的差异均达到极显著水平(P<0.01)。     

A Study of Losses in Scots Pine caused by Fomes annosus

Data are presented from unreplicated Scots pine {Pinus sylvestrisL.) sample plots in Thetford Forest which have been differentiallyattacked by Fomes annosus (Fr.) Cooke. Volume production ofseverely infested crops differs markedly from that forecastby management tables. The volume of dead trees may not representthe total loss of volume in these plots as there appears alsoto be a reduction in the growth of the remaining live trees.These observations may have considerable significance in forecastingfuture volume production from stands attacked by F. annosusand also in deciding the optimum time for their replacement.     

The Internal Transfer of Nutrients in a Scots Pine Stand 2. The Patterns of Transfer and the Effects of Nitrogen Availability

The fall of fine litter was 4.5 tonnes ha^–1 y^–1,(78% needles) returning to the ground 36.6 kg N, 2.2 kg P, 7.6kg K, 12.1 kg Ca and 2.0 kg Mg. Nutrient input in rainfall (880mm in 1978) was 2.6 kg N, 0.4 kg P, 4.3 kg K, 7.6 kg Ca and1.4 kg Mg. Throughfall was 534 mm. The method of Miller, Cooperand Miller (1976) was used to estimate aerosol contributions,leaching and absorption. Retranslocation estimates were 59.6kg N ha^–1 y^–1 (55% of Requirement), 8.5 kg P (64%R), 42.0 kg K (56% R) and 1.2 kg Mg (14% R). Retranslocationwas unchanged, but uptake increased with added N % P and decreasedwith added sawdust and glucose. Other typical effects of nutrientamendment were observed: with added N % P growth increased,current tissues had higher concentrations of N and P and litterfalldecreased in the first year but was heavier in the second year:with added sawdust and glucose, growth declined but concentrationsof N and P remained substantially the same.     

The Estimation of Foliage Area from Sapwood Basal Area in Scots Pine

A linear relationship between the cross sectional area of sapwoodat 1·3 m above ground level and the foliage area on eleventrees was determined in a Scots pine (Pinus sylvestris L.) spacingexperiment. The relationship was independent of tree spacing.With increasing tree numbers per unit ground area tree heightremained constant, mean tree diameter was less, basal area andvolume were greater but leaf area index varied little. A model was used to predict the vertical distribution of foliagearea with height for one of the plots from the measurementsmade on the other three.     

Ground Vegetation and Humus Nitrogen Levels as Indicators of Nitrogen Status in an Established Sand-Dune Forest

Association-analyses of the ground vegetation in two nitrogen-fertilizerexperiments in pole-stage pine growing on wind blown sand suggestedthat the appearance, in order, of Agrostis tenuis, Rumex acetosella,Chamaenerion angustifolium, and Holcus lanatus was associatedwith increasing rates of nitrogen. In the forest as a whole,the progressive appearance of these species was found to beindicative of both increasing tree growth and increasing concentrationof nitrogen in the humus. In particular, the level of nitrogenin the humus is suggested to be a good, and possibly useful,measure of the nitrogen status of the site.     

Genotypic Variation among Native Scots Pine Populations in Scotland based on Monoterpene Analysis

The monoterpene composition of the shoot cortical resin of 6705native Scots pine trees from 41 sites in Scotland was determinedby gas chromatography. Each tree was allocated to one of a numberof biochemical genotypes. Variation between sites allowed thenatural range to be divided into several areas of biochemicalsimilarity, the most distinct being a north-western group ofsites with Shieldaig as its most distinctive site. Other areasincluded a northern group, a south-western group centred onthe Great Glen, a central north-south region, central Speyside,and outer Speyside/eastern Deeside. Variation was detected atseveral levels within some woodlands. Relationships betweensites and between regions, as shown by mathematical analysesof the biochemical parameters, can be used as a guide in planningreplanting programmes.     

基于GIS海岛土壤有机质和全氮空间变异特征的初步研究

利用统计分析和GIS空间分析模块初步分析了舟山市岱山本岛土壤pH、有机质含量、全氮含量3个土壤性质指标的空间变异特征,揭示这些指标空间变异的主要影响因素,并利用克立格插值法生成三者含量的空间分布图.结果表明:土壤表层pH、有机质、全氮含量变异系数分别为0.11、0.13和0.54,存在中等程度的变异性,且三者空间分布条带状或斑块状分布明显.土壤有机质和全氮含量相关系数达到极显著水平(P＜0.01),两者空间分布格局具有相似性;研究区土壤表层pH、有机质、全氮空间变异性主要受到植被分布、土壤类型、地形等因素的影响,土壤有机质含量空间变异性受植被因素影响明显.     

An Analysis of Peridermium Stem Rust of Scots Pine in Thetford Forest in 1984 and 1985

The status of stem rust (Peridermium pini or (Pers.) Lev.) inScots pine (Pinus sylvestris L.) in the central block of Thetfordforest, East Anglia was determined by means of detailed analysisof freshly felled trees. A total of 935 trees was examined,these comprising c. 100 from each of nine compartments plantedbetween 1922 and 1933. Lesions in all stages of development were found; from thosein their first year of sporulation on young twigs to those whichhad been established for many years on the trunk and main branches.Death of cambium occurred typically on lesions on shoots thatwere more than five years of age. Downward growth of the funguswas estimated to average between 4.7 and 5.6 cm per year, whenbased on the length of sporulating tissue on young twigs, and6.3 cm per year when based on cambial killing in trunk lesions.The average rate of circumferential killing of trunk lesionsaveraged 4.3 crn per year (i.e. 2.2 cm in each direction). Therewas no evidence that wounds provided a significant infectioncourt. A strong association was found between the presence of the ‘purplemould’ (Tuberculina maxima) and an absence of sporulationby the rust fungus. However, there was no evidence for lesioninactivation by T. maxima. Data are presented on the distribution of disease between sitesand between trees. Five per cent of the total sample of treeswere dead and an additional 12 per cent had crown symptoms associatedwith girdling trunk lesions. Among the 775 trees with predominantlyhealthy crowns, it is estimated that 9 per cent would have diedwithin 5 years, 15 per cent within 10 years and 22 per centwithin 20 years. By contrast 66 per cent had no disease at all,probably for genetic reasons. It is concluded that, althoughthe disease situation is serious, there is no requirement fora major change to be made in the felling programme for the pre-warScots pine in Thetford.     

Competitive Interactions between Norway Spruce and Scots Pine at Gisburn Forest, NW England

Species mixtures, although promising for improving the growthof spruce on nitrogendeficient sites, carry a risk of competitionfrom the admixed nurse species. The mixture of Scots pine (Pinussylvestris) and Norway spruce (Picea abies) planted at GisburnForest in 1955, in which nutritional benefits have been observed,provided a unique opportunity to study competition between thesespecies. Pure plots of both species as well as the mixture werereplicated in three blocks, allowing the effects of interplantingon the survival and mean diameter of each species to be testedstatistically. Further, the grouped arrangement of the speciesin mixed plots presented a variety of competitive configurationsbetween the two species. Instead of demonstrating the nursing benefit of pine to spruce,comparisons of mean diameters in pure and mixed stands indicatedthat spruce suffered and pine benefited from their interplantingat this site. Frequency distributions of tree diameters confirmedthat spruce tended to be suppressed in mixture and pine dominant.Neighbour analysis revealed that spruce were significantly smallerwhen adjacent to pine and that this effect was mainly due tothe larger size of pines. The increased height of spruce atthis site, previously attributed to a nutritional benefit conferredby pine, was probably due to competition for light from an overtoppingnurse. Nurse varieties must be carefully selected if they areto promote rather than suppress the growth of crop trees.     

Soil Physical Factors Affecting Root Morphology and Stability of Scots Pine on Upland Heaths

Forty trees, on five heathland soil types, were pulled overand their resistance compared with described profile and physicalfeatures. Root morphology was found to be important for stabilityas was stem weight and soil strength. Ironpans reduce permeabilityto vertical drainage and delay but do not bar limited root penetrationto the lower horizons. Root extension ceases at soil densitiesof about 1·5 g./cc. On freely rooted profiles root systems may continue to expandbut on ironpan soils have occupied available space (at 30 years)and further increases in tree size will result in increasedinstability.     

樟子松人工林树冠结构模型及三维图形可视化模拟

以东北林业大学帽儿山实验林场樟子松人工林为研究对象,采用树干解析、枝解析的方法,分别于2002和2003年在老山施业区选择不同年龄、不同立地和不同密度的樟子松人工林有代表性的林分设置固定标准地15块(2002年设置7块,2003年设置8块),共获取解析样木53株,实测2298个一级枝活枝条变量因子(包括总着枝深度、方位角、着枝角度、基径、枝长、弦长、弓高)数据资料.基于理论或经验生长方程,建立樟子松人工林树冠结构静态模型及树冠动态生长模型.采用VC++6.0语言为开发平台,结合OpenGL开放式图形库,将生长模型与形态结构模型结合,建立樟子松人工林树冠动态三维图形可视化模拟系统,实现基于实测数据和生长模型的静态、动态单木和林分的可视化模拟.     

Prevention of Blue-stain in Unpeeled Scots Pine Logs: (With 2 Plates)

Blue-stain causes degrade of saw logs during the inevitabledelays between felling and conversion. Chemicals of potentialvalue in blue-stain control have been tested in the laboratoryand trials have been made of their use on unpeeled logs storedin the forest. End treatments with fungicides were not very effective duringsummer storage of logs. Whole log treatments with a combinedfungicide and insecticide containing 2 per cent. Santobrite,2 per cent. borax, and 0?75 per cent. BHC gave very good protectionfor 3 months. End treatment with fungicides followed by whole-logtreatment with insecticides was also effective. Protection byeither method of treatment was lessened during longer storageperiods especially in the warmer months of the year. Whole-logtreatment with insecticide alone gave a good measure of controlof stain. Short delays after felling before the application of whole-logtreatments may be acceptable especially on logs which have previouslyreceived end treatments. Attack by bark-boring insects must be controlled if effectiveall-the-year protection against blue-stain is required. Insectattack appears to be secondary only to time of felling in relationto incidence of blue-stain. The value of winter felling hasbeen confirmed.     

生物制剂对沙地樟子松造林成活率及根系生长影响的研究

采用Pt菌剂、ABT生根粉、HRC吸水剂、丰产素等生物制剂处理2年生樟子松苗木，在内蒙古加格达齐进行了田问造林试验。并对樟子松造林成活及地下根系生长效应进行了研究，观测苗木成活率、根系生长等因子。结果表明：Pt菌剂3号ABT生根粉制剂显著地提高了樟子松成活率，它分别比对照高29．3％和23．6％，也促进了根系的生长，特别是细根的增加。回归分析表明苗木细根长度与苗木成活率呈显著正相关，说明生物制剂提高成活率是通过增加细根量来实现的。表3参10。     

杨木和樟子松单板的光变色规律

以杨木和樟子松单板为试材,利用氙光衰减仪进行光辐射试验,分析其光变色规律,并进行耐光性能评价.结果表明:木材受光辐射易发生变色,主要表现为明