昆明树木园观赏植物资源及园林应用评价

采用实地调查与分析相结合的方法,对昆明树木园的观赏植物及其应用情况进行了调研,在整理出昆明树木园观赏树种名录的基础上,分析了其生长习性、观赏特性和园林用途等,并对其观赏价值进行了综合评价。     

Use of the management-oriented silvopastoral model ALWAYS: Calibration and evaluation

The ALWAYS model simulates the biophysical functioning of a silvopastoral plot – here the broad-leaved tree — pasture — sheep association — and its management, according to the interactions between the different components of the system. The model was calibrated for two silvopastoral plots with contrasting soil and climate: at Lamartine in central France (wet upland climate), and at Cessous in southern France (a moderate hot and dry Mediterranean climate). The actual plot management recorded in the field was used in the model (and particularly date and number of grazing animals) and the model was run for different time series (from 2 to 100 years) depending on the process we wanted to evaluate, grass and animal production or tree growth. Models outputs were consistent with recorded data on the field and we concluded that the model can correctly simulate the behaviour of a silvopastoral plot in terms of tree growth, grass production, animal grazing and interactions between the different components. It permitted also to make consistent choices and compare different strategies of silvopastoral plots management. The improvement of some biophysical processes that are very simplified in the model is required to produce better accurate predictive values of sward or tree production. But a much more complex model will require more data for its parametrization and more time to run, precluding its use in many situations.This revised version was published online in November 2005 with corrections to the Cover Date.     

植物构筑型研究综述

植物构筑型作为一门新兴的学科日益受到相关工作者的重视, 系统地分析植物构筑要素为更深入地研究植物的形态结构提供了可靠的依据。介绍了研究植物构筑型的意义、植物构筑型的研究历史, 归纳总结了植物构筑型的有关概念, 讨论了当前的研究状况、存在的问题及发展趋势。     

Understanding forest transition in the Philippines: main farm-level factors influencing smallholder’s capacity and intention to plant native timber trees

The ‘when, where and how’ of decisions by smallholder upland farmers to plant trees as part of their use of natural, human and capital resources needs to be understood if policy support is to result in actual recovery of tree cover as part of a ‘forest transition’ trajectory. In large parts of the Philippines the turning point may be close. Data on resource access and tree planting decisions were gathered from a household survey, with a total of 148 respondents in four rural communities in Leyte Province in Central Philippines. Data were analysed using logistic regression analysis. Household-level results reveal that the outcomes of the decision-making processes primarily depend on the availability of land and access to remaining forest resources rather than socio-cultural or economic factors. The total area of land and number of parcels managed by the household plus security of land tenure through ownership was found to have a statistically significant effect on farmers’ decision to plant native timber trees. Access to surrounding natural forest is negatively associated with farmer tree planting.     

Stochastic modelling of tree annual shoot dynamics

• Context  

Modelling annual shoot development processes is a key step towards functional–structural modelling of trees. Various patterns of meristem activity can be distinguished in tree shoots, with active periods of phytomer production followed by rest periods. This approach has seldom been integrated in functional–structural tree models.     

Simulating effects of fire on northern Rocky Mountain landscapes with the ecological process model FIRE-BGC

A mechanistic, biogeochemical succession model, FIRE-BGC, was used to investigate the role of fire on long-term landscape dynamics in northern Rocky Mountain coniferous forests of Glacier National Park, Montana, USA. FIRE-BGC is an individual-tree model-created by merging the gap-phase process-based model FIRESUM with the mechanistic ecosystem biogeochemical model FOREST-BGC-that has mixed spatial and temporal resolution in its simulation architecture. Ecological processes that act at a landscape level, such as fire and seed dispersal, are simulated annually from stand and topographic information. Stand-level processes, such as tree establishment, growth and mortality, organic matter accumulation and decomposition, and undergrowth plant dynamics are simulated both daily and annually. Tree growth is mechanistically modeled based on the ecosystem process approach of FOREST-BGC where carbon is fixed daily by forest canopy photosynthesis at the stand level. Carbon allocated to the tree stem at the end of the year generates the corresponding diameter and height growth. The model also explicitly simulates fire behavior and effects on landscape characteristics. We simulated the effects of fire on ecosystem characteristics of net primary productivity, evapotranspiration, standing crop biomass, nitrogen cycling and leaf area index over 200 years for the 50,000-ha McDonald Drainage in Glacier National Park. Results show increases in net primary productivity and available nitrogen when fires are included in the simulation. Standing crop biomass and evapotranspiration decrease under a fire regime. Shade-intolerant species dominate the landscape when fires are excluded. Model tree increment predictions compared well with field data.     

树体结构研究的历史发展和现状──兼论树体三态结构划分及其意义

文中综述了有关树体结构的研究历史，着重分析了树体结构的研究现状，并在此基础上，详细论述了树体结构的三态（形态结构、质态结构和动态结构）划分及其意义。     

关于C-D效果和3/2乘则与单位面积产量相互关系的研究

本文以白榆密度试验的观测数据为基础,探讨了1nW与1nN直线方程斜率的变化与单位面积产量间的关系。以斜率的数值与产量关系为标准,把斜率的变化分成3个区域,以表示竞争强度对个体生长和单位面积产量的不同作用。斜率B为C时,竞争未影响到个体生长,产量随密度增加而增加,是无竞争区域;斜率B为0>E>-1时,竞争虽有抑制个体生长的作用,但单位面积产量却随着密度的增大、竞争的增强而增加,是增产竞争区域;当斜率B为-1>B≥-1.5时,竞争强度达到了既抑制个体生长又影响单位面积产量的程度,所以叫减产竞争区域。B=-1时,是增产竞争和减产竞争的分界点,叫做稳产竞争状态。指出斜率B=-1可以作为密度管理合理性的标准。斜率B=-1.5时,各密度间存在着异质性,不宜作为密度管理的基础。     

Climate signal age effects—Evidence from young and old trees in the Swiss Engadin

A potential limitation of tree-ring based climate reconstructions is related to climate signal age effects (CSAE). CSAE may arise if the climatic response of young tree-rings differs from that of old tree-rings. This could mean that climatic signals become stronger (or weaker) with tree aging, or that the seasonality of signals or the sensitivity to a specific element (e.g., temperature, precipitation) changes over time. Such changes would affect the interpretation of dendroclimatic reconstructions, as the tree-rings included in these records are generally oldest at the end of a record (e.g., 21st century)—which is the time period generally used for calibration with instrumental data.We here addressed this concern by analyzing young and old Pinus cembra trees from three high elevation sites in the central European Alps. Core and disc samples were collected in pre-defined plots to allow for a representative analysis of tree ages with tree-ring width (TRW) measurement series categorized into age classes (i) >1880, (ii) 1880–1939, and (iii) 1940–2002. Notably we report on the signal of the very young category (iii) not yet described in literature, and thus allow estimation of climate response and signal strength characteristics during the first years of the trees’ lifespans.Comparison of age classes (i)–(iii) revealed differences in TRW coherence and size, but little change in climatic signal. CSAE are in the order of the differences recorded among high elevation sites—a conclusion that holds for inter-annual to decadal scale TRW variations at near-treeline Swiss stone pine. Such data are typically included in regional and larger-scale temperature reconstructions; thus, our results add confidence to long-term climate estimates integrating a range of tree-ring age classes. Other findings, such as the reaction wood in juvenile tree-rings, and sensitivity of the climate signal to sample replication, suggest that comparisons of young and old age classes, and separate calibration of these categories against instrumental climate data might further the estimation of long-term uncertainty changes in tree-ring based climate reconstructions.     

Fertilizers in agroforestry systems

This review encompasses results of fertilization experiments on several agroforestry systems—alley cropping, perennial shade systems, home gardens—in which fertilizer use is a likely management alternative. Fertilizer response was found to be most common in alley cropping, variable in perennial shade systems, and rarely reported in home gardens. Level of nutrient removal in harvested products is probably the overriding factor in determining fertilizer response; greater accumulation of organic residues, slower growth under shade, and longer periods of nutrient uptake probably also contribute to the relatively smaller fertilizer response of the perennial shade systems and home gardens. Considerable knowledge gaps exist regarding the breakdown of organic residues, and interactions between mineral and organic amendments. Systems based on annual crops (e.g., alley cropping) are likely to be less nutrient-efficient and sustainable than systems based on perennial crops, due to reduced fixation and transfer of N to the crops, the tendency of the trees to compete for and sequester nutrients, relatively high P requirements of the crops, and the high labor cost of tree management. The possible benefits of fertilization of specific components in home gardens, and relative advantages of including low-value tree legumes, high-value shade trees, and fertilization in shaded perennial systems are only beginning to receive research attention.     

Insect pest problems in tropical agroforestry systems: Contributory factors and strategies for management

Agroforestry trees are attacked by a wide spectrum of insects at all stages of their growth just like other annual and perennial crops. Pest management in agroforestry has not received much attention so far, but recent emphasis on producing high value tree products in agroforestry and using improved germplasm in traditional systems, and emergence of serious pest problems in some promising agroforestry systems have increased awareness on risks posed by pests. Insects may attack one or more species within a system and across systems in the landscape, so pest management strategies should depend on the nature of the insect and magnitude of its damage. Although greater plant diversity in agroforestry is expected to increase beneficial arthropods, diversity by itself may not reduce pests. Introduction of tree germplasm from a narrow genetic base and intensive use of trees may lead to pest outbreaks. In simultaneous agroforestry systems, a number of factors governing tree—crop—environment interactions, such as diversity of plant species, host range of the pests, microclimate, spatial arrangement and tree management modify pest infestations by affecting populations of both herbivores and natural enemies. Trees also affect pest infestations by acting as barriers to movement of insects, masking the odours emitted by other components of the system and sheltering herbivores and natural enemies. In sequential agroforestry systems, it is mostly the soil-borne and diapausing insects that cause and perpetuate damage to the common hosts in tree—crop rotations over seasons or years. An integrated approach combining host-plant resistance to pests, exploiting alternative tree species, measures that prevent pest build up but favour natural enemies and biological control is suggested for managing pests in agroforestry. Species substitution to avoid pests is feasible only if trees are grown for ecological services such as soil conservation and low value products such as fuelwood, but not for trees yielding specific and high value products. For exploiting biological control as a potent, low cost and environmentally safe tool for pest management in agroforestry, research should focus on understanding the influence of ecological and management factors on the dynamics of insect pest-natural enemy populations. Scientists and policy makers in national and international institutions, and donors are urged to pay more attention to pest problems in agroforestry to harness the potential benefits of agroforestry.This revised version was published online in November 2005 with corrections to the Cover Date.     

The effect of whole-tree harvesting on the growth of second rotation Sitka spruce

Stem analysis has been used to examine the effects of two harvestingtechniques upon growth of second rotation Sitka spruce plantedin 1981 on a peaty gley site of low fertility in Kielder Forest,Northumberland. The effect of NPK fertilizer upon tree growthon conventionally harvested plots was also determined. Weedcompetition was reduced by hand weeding and the applicationof herbicides. Repeated measures analysis was used to identifythe time at which significant growth responses occurred. Whole-tree harvesting reduced mean tree volume from 1986 onwardswhile the addition of fertilizer to conventionally harvestedplots increased volume growth from 1990. By 1993, whole-treeharvesting had decreased mean tree volume by 32 per cent andthe addition of fertilizer to conventionally harvested plotshad increased mean tree volume by 13 per cent. Observed treatment effects are most likely due to the increasedremoval of nutrients during hole-tree harvesting. The releaseof nutrients from decomposing residues is expected to meet uptakerequirements for approximately 7–9 years following replanting.Effects of shelter and weed competition should also be consideredon sites where herbicides have not been used to control groundvegetation. Repeated measures analysis and the use of suitablegrowth functions provide powerful analytical tools to examinehistorical treatment effects derived from stem analysis.     

植物激素对黄檗幼树生长性状的影响及生物量模型的构建

以黄檗5 a生幼树为材料,对叶面喷施不同组合的植物激素,利用正交设计,研究其对生长性状的影响,并建立生物量模型,结果表明:栽植当年和翌年秋季幼树的成活率与保存率分别为97%和95%,平茬与未平茬在定植2年后未发现生长性状有显著差异;植物激素不同组合处理对幼树树高、地径生长量影响较为明显,3种植物激素对树高和地径生长量影响大小依次为NAA6-BAGA3;有效促进树高生长的最佳植物激素配比为NAA200 mg·L-1+6-BA400 mg·L-1+GA3400 mg·L-1,有效促进地径生长的最佳植物激素配比为NAA200 mg·L-1+6-BA400 mg·L-1+GA3200 mg·L-1。地径是影响生物量的主因子,拟合程度最高的一元生物量方程为Y=0.061-0.083X+0.047X2。     

Relationships between nursery practices and field performance for Eucalyptus plantations in Brazil

The 3.5 million ha of Eucalyptus plantations in Brazil support many domestic and industrial activities. In the pulpwood sector, forest productivity has increased from 12 to 40 m³ ha^–1 year^–1 through breeding and silviculturalpractices. Nurseries have fostered thisevolution with changes in container/substratetypes, propagation methods and specificinfrastructure for each plant growth phase.Eucalyptus plants are mainly produced bycuttings, using rigid tube containers filledwith vermiculite-organic compound substrates.Stock quality is based on morphologicalcharacteristics of the plants, andenvironmental conditions are highly significantfor plant performance. Performance is dependenton physiological short-term effects related tosurvival and long-term effects of genotype/rootmorphology related to tree development. Currentsilvicultural trends are reducing establishmentcosts but increasing the risk of using lowquality plants. The development of fieldperformance models and nursery physiologicaltests is recommended for Eucalyptusplantations in Brazil. Improved experimentaldesigns are needed to capture the interactionbetween plant quality and field performance.     

Growth and survival of termite-piped Eucalyptus tetrodonta and E. miniata in northern Australia: Implications for harvest of trees for didgeridoos

The most common canopy trees in the savannas of northern Australia, Eucalyptus tetrodonta and E. miniata are also two of the most common species harvested to make didgeridoos, the traditional musical instrument of northern Australian Aboriginal peoples now experiencing high demand from international markets. Most of the trees of the area naturally have hollow cores, or pipes, due to termite activity, but little is known of the relationships of the cores to size of tree, tree growth or survival. In a wooded savanna of northern Australia, 267 individual trees with known growth and survival rates were cored to determine degree of termite-piping. Generalized linear modelling and multi-model inference showed that frequency of piping increased with diameter (dbh) tree for E. tetrodonta, but >85% of E. miniata trees were piped regardless of dbh. Growth (dbh increment) and survival (4-year) were size-dependent. Survival of both species decreased strongly with degree of piping (pipe ratio). For any given diameter, the growth rate of E. miniata trees was independent of pipe ratio, but for E. tetrodonta trees decreased strongly with pipe ratio. From modelled data, a 10-cm tree with pipe ratio of 0.60 was very vulnerable, growing at 0.0 cm year⁻¹ with 46% survival rate, whereas a 40-cm tree, even with large pipe ratios (0.80), grew 0.05 cm year⁻¹ with 98% survival rate. Traditional methods of tree harvesting remove only those smaller hollow trees that are already suffering low growth rates and are likely to die before reaching maturity, whereas current large-scale commercial methods also remove trees with higher growth and survival rates—those trees most likely to contribute to sustainable tree populations. Incorporating traditional selection and harvest methods into current commercial operations would help ensure longevity of this source of livelihood for indigenous peoples of the region.     

Biochemical and molecular genetic markers in biosystematic studies of forest trees

Biochemical and molecular markers have proven to be powerful tools for discerning biosystematic, biogeographic, and phylogenetic relationships. Biosystematic information can be important for guiding traditional breeding programs, gene transfer, interspecific hybridization, and gene conservation. A phylogenetic framework is usually necessary, but frequently ignored, for making valid statistical tests in studies of adaptive evolution. Several studies have indicated a strong correlation between biochemical races and traits important to growth and adaptation, suggesting that evolutionary legacy may affect genetic architecture of fitness traits — with consequences for seed transfer, breeding strategies, and tolerance of climate change. A number of methods for phylogenetic analysis exist, but differ in their assumptions. Use of an inappropriate method — such as a method that assumes constant rates of evolution when rates in fact vary — can lead to incorrect phylogenies. Because of their complexity, phylogenetic topologies are often difficult to determine unambiguously; estimates of statistical confidence should therefore accompany phylogenetic trees if they are to be regarded as providing new knowledge, or strong confirmation, of relationships. Molecular genetic markers are more expensive than biochemical markers such as allozymes and terpenes, but they provide increased accuracy and expanded scope of biosystematic inference, and facilitate statistical analyses of phylogenetic trees.Abbreviations BMGMs biochemical and molecular genetic markers - cpDNA chloroplast DNA - OTU operational taxonomic unit - rbcL chloroplast gene encoding ribulose 1,5-bisphosphate carboxylase large subunit - rbcS nuclear gene encoding ribulose 1,5-bisphosphate carboxylase small subunit - rDNA ribosomal DNA - RFLP restriction fragment length polymorphism - UPGMA unweighted pair group method of clustering using averages This is paper 2708 of the Forest Research Laboratory, Oregon State University.     

Direct impacts of sheep upon Douglas-fir trees in two agrosilvopastoral systems

Livestock may provide important service and production functions in agroforestry systems. However, use of livestock in conifer/improved pasture agrosilvopastoral systems is currently limited by concerns about potential damage to trees by livestock. Effects of sheep grazing on Douglas-fir (Pseudotsuga menziesii) trees in two patterns of sheep/pasture/conifer agroforest (cluster and grid plantations) were studied from 4 years after planting (1983) until the first precommercial thinning at age 10 years (1988). Trees averaged over 1 m in height when grazing began in summer 1983. Some browsing of tree lateral branches by sheep occurred regardless of grazing season in 1983–1985. However, the 2 to 10% of current year's lateral branch growth removed by grazing sheep was too low to impact tree growth. Sheep removed the terminal leaders from only 3 to 9% of trees each year during 1983–1985. Most browsing of terminals occurred in the summer when other forages had become mature and were relatively unpalatable to sheep. Less than 13% of agroforest trees were debarked by sheep each year during 1983–1987. By the end of grazing in 1987, less than 8% of agroforest trees had sustained a level of debarking likely to impact future growth (>50% of tree circumference debarked). Grazing had no discernible effect upon tree diameter or height in any year (P > 0.05). Total tree mortality attributable to sheep grazing during 1983–1987 was only 0.9%, including three trees girdled by sheep and two debarked trees which were subsequently attacked by insects. Overall, grazing had no detrimental impact on timber stand growth or mortality.Submitted as Oregon Agricultural Experiment Station Technical Paper No. 9628.     

基于固定样地的林分乔木层年净生产力参数结构化估算

为更准确估算林分乔木层年净生产力,解析林分乔木层生产力的构成,本研究提出了基于固定样地数据的林分乔木层年净生产力参数结构化估算方法。利用天台县2009-2014,2014-2016,2016-2017年3个阶段固定样地数据,同时考虑森林类别、树种组、龄组等因子,结构化估算4组参数,第1组是保留木生物量年均生长率,第2组是生物量年均保留率,第3组是进界木生物量年均生长率,第4组是单位面积年均进界株数。第1组参数结果表明,各树种组保留木生物量年生长率随着龄组增大而减小;商品林保留木生物量年均生长率普遍比公益林高。第2组参数结果表明,公益林内所有树种组的生物量年保留率都低于其在商品林内的保留率。第3组参数结果表明,除硬阔Ⅰ类外,公益林中其他树种进界木生物量年均生长率都高于商品林。第4组参数结果表明,随着龄组的增大,单位面积年进界木株数减少;任一龄组下,公益林中的单位面积年进界木株数均高于商品林。研究结果表明,本方法能够解析乔木层生产力的构成情况,是一种结构化估算方法,其计算结果与其他相关研究相比更具优点。     

Silvopastoral systems in northwestern Patagonia. I: growth and photosynthesis of Stipa speciosa under different levels of Pinus ponderosa cover

Combination of native pastures with fast-growing tree species (mainly Pinus spp.), may be an interesting economic and environmental alternative for small and medium land-owners in Patagonia,Argentina. Pasture productivity is usually the single most important factor affecting livestock carrying capacity. Therefore the prediction of the effects of tree cover on understory herbaceous production is of great importance for management. This paper reports the growth response of Stipa speciosa Trin. et Rupr. (tillering, tiller height, number of green leaves per tiller, and relative growth) to Pinus ponderosa Doug. (Laws) canopy cover (0 to 100%). Grasses did not grow when crown cover was >70%. Tiller production and relative growth were negatively correlated with tree cover; tiller height was larger under high tree cover. There was no relationship between leaf production and tree canopy cover. Grass leaves maintained net photosynthetic rates, at similar light levels, at a wide range of plant water potentials (from saturation to at least –2.4 MPa). Decrease in photosynthesis occurred at very low plant water potentials (–4.3 MPa). No differences in photosynthetic rate at similar radiation levels were foundbe tween plants growing in different light environments (determined by tree cover) in the field. Stipa speciosa can maintain positivenet CO₂ assimilation and growth under moderate shading and severewater stress conditions. For this reason, it can be used in silvopastoral systems, with a proper light management.This revised version was published online in November 2005 with corrections to the Cover Date.     

Faidherbia albida and its effects on Ethiopian highland Vertisols

On a Vertisol under 850 mm rainfall, at an altitude of 1850 m, Faidherbia albida trees that occurred at 6.52 trees ha^–1, with a canopy cover that range from 97 m² ha^–1 to 229 m² ha^–1 were recorded. Studies on the lateral and vertical influence of the tree canopy on some physical and chemical properties of the soil, show apparent higher organic matter on the West side of the tree than the East due to accumulated wind blown litter by prevalent wind direction, and organic matter, N, P and K levels were higher under the tree canopy than outside for all directions and depths studied. Soil pH, exchangeable Na, Ca and Mg under the canopy and outside were similar. Available water capacity was 1.5 to 2 times more under than outside the tree. Noticeable increases in the silt fraction under the tree was recorded and discussed in relation to soil condition improvement and plant growth.