Fine root dynamics of shaded cacao plantations in Costa Rica

Root turnover may contribute a significant proportion of recycled nutrients in agroforestry systems and competition between trees and crops for nutrients and water may depend on temporal fine root regrowth patterns. Fine root biomass ( 2 mm) and fine root productivity were measured during one year in plantations of cacao (Theobroma cacao) shaded by Erythrina poeppigiana or Cordia alliodora planted on a deep alluvial soil in Turrialba, Costa Rica. Fine root biomass of approximately 1.0 Mg ha^–1 varied little during the year with maximum values at the beginning of the rainy season of 1.85 Mg ha^–1 in the cacao-C. alliodora system compared to 1.20 Mg ha^–1 for cacao-E. poeppigiana. Fine root productivity of C. alliodora and E. poeppigiana (maximum of 205 and 120 kg ha^–1 4 week^–1, respectively) was greatest at the end of the rainy season, while for cacao it was greatest at the beginning of the rainy season (34–68 kg ha^–1 4 week^–1), which suggests that if nutrient competition occurs between the shade trees and the cacao, it could be minimized by early fertilization during the beginning of the rains immediately after pruning the shade trees. Annual fine root turnover was close to 1.0 in both systems. Assuming that fine root biomass in these mature plantations was constant on an annual basis, nutrient inputs from fine root turnover were estimated as 23–24 (N), 2 (P), 14–16 (K), 7–11 (Ca) and 3–10 (Mg) kg ha^–1 year^–1, representing 6–13% and 3–6% of total nutrient input in organic matter in the C. alliodora and E. poeppigiana systems, respectively.     

隆回县候鸟种类与迁徙路线调查报告

对湖南省隆回县候鸟种类及迁徙路线的调查结果表明,隆回县候鸟资源较为丰富,共记录鸟类26科95种,其中国家Ⅱ级保护鸟类18种。同时确定了该地区主要候鸟类迁徙停歇地及春秋两季迁徙路线,为该地区鸟类资源的有效保护和管理提供了科学依据。     

Productivity of Southern Brazilian coffee plantations shaded by different stockings of Grevillea robusta

A field experiment was conducted from 1984 to 1994 in the North of Paraná State, Brazil (23°45′ S, 52°30′ W), to evaluate the effect of Grevillea robusta (grevillea) on interplanted coffee. Grevillea was planted in five densities (26, 34, 48, 71, and 119 trees per ha). Compared with open grown coffee, there was no decline in the yield of coffee under grevillea at densities of 26, 34, and 48 trees per ha; however, total economic productivity (including the value of both coffee and grevillea) was higher for combinations of coffee and grevillea at 34, 48, and 71 trees per ha. The severe radiative frost of June 1994 that damaged most coffee plants did not damage coffee plants interplanted under grevillea trees at densities of 71 and 119 trees per hectare. This revised version was published online in June 2006 with corrections to the Cover Date.     

Towards standardised crown condition assessment in poplar plantations

? This work aims at developing new tools for rapid assessment of forest health indicators in poplar plantations.

? Crown transparency and discoloration were visually evaluated in all trees of four 15 m-radius sub-plots in 32 poplar clonal plantations, which were chosen according to a factorial scheme with three factors: tree age, site quality and understorey vegetation management. A subset of trees was assessed using digital photos processed with a semi-automatic image analysis system (the CROCO software) in order to compare visual and digital crown transparency estimates.

? Poplar crown conditions were better in young stands and rich sites. Harrowing understorey vegetation improved tree health in poor sites. Samples of 20 trees per stand provided the same information about crown transparency and discoloration as 60 trees. Calibration curves of digital crown transparency estimates were successfully fitted against visual crown transparency estimates. The same effects of stand age and site quality could be detected with digital crown transparency as response variable.

? The use of digital photos processed with CROCO in ca. twenty trees per stand is therefore recommended to accurately and objectively monitor crown condition in clonal poplar plantations.

     

向海湿地迁徙鸟类的调查分析与保护对策

连续4 a对向海湿地迁徙鸟类进行调查与分析,结果表明:湿地整体生境呈缓慢恢复态势;以2005年为调查基准年,2006年2、007年、2008年迁徙鸟类的种类分别增加了8.6%、11.4%、10.0%,种群数量分别增加了87.8%、75.5%、59.8%,迁徙鸟类的种类和种群数量呈增加趋势。自然力作用的湿地缺水旱化和人畜活动仍是影响迁徙鸟类生境的2个主要原因。加强湿地生境保护、开展湿地功能恢复与提高技术的研究、开展迁徙伤病鸟救治、建立多方合作保护体系等是有效对策。     

Hybrid poplar plantations in a floodplain have balanced impacts on farmland and woodland birds

Hybrid poplar plantations are increasing worldwide and are often accused of impoverishing bird communities. We conducted 124 bird point counts in a landscape where plantations, semi-natural forests and farmland occupied similar surface areas. As expected, birds occurred at higher densities in areas dominated by forests than dominated by plantations, mostly due to the scarcity of late-successional forest birds in plantations. Contrary to expectations, bird communities were the poorest in farmland dominated areas and the most specialised in areas dominated by young plantations. Indeed, many grassland species, including some of conservation concern in Europe, frequently used young plantations. However, plantations have probably depleted grassland bird communities by fragmenting open areas, while playing a limited positive role on forest species. Total length of unpaved roads had a positive effect on community specialisation index, while total length of paved roads and mean forest/plantation patch size played no role. Bird density increased with the development of the understory vegetation in mature poplar plantations. We conclude that poplar should not be planted at the expense of areas of high conservation value; in other cases, they may increase the overall diversity of bird communities. At the plantation scale, we advocate stopping understory removal as soon as possible and maintaining old trees and hedgerows alongside or within plantations to provide suitable breeding habitats for bird species that may be foraging in the plantations.     

Ecological distribution and seasonal change of soil microorganisms in pure and mixed plantations

lntroductionSoiImicroorganismsareimportantingredientsinsoilandobviouslyaff6ctsoiIf6rtiIity,andtheycanchangethephysicochemicaIpropertiesofthesoilsbythejrmetabolicactivities.The'reproductionofmi-croorganismscanintensiveIyinffuencegrowthanddeveIopmentofpIants.Therootsoffensecretevari-OuskindsofexosmosemateriaIsuchassaccharide,aminoacidandvitamins,whichcanalsostimuIatethereproductionofthesoilmicroorganisms.Thenumberandspeciesofthesoilmicroorgaoismsaredifferentwiththechangeofthesoiltype,environ…     

Financial analysis of shaded cocoa in Ghana

The cultivation of cocoa has been an important driver of tropical deforestation globally. Efforts to reverse this trend are focusing on the reintroduction of shade trees to cocoa plantations. Shade trees are valuable in enhancing biophysical conditions on cocoa (Theobroma cacao) fields and contribute to biodiversity and product diversification for smallholder producers. Participatory trials of cocoa agroforests planted with indigenous shade tree species were undertaken with farmers in the Atwima District of the Ashanti Region of Ghana, to increase tree volume on cocoa fields while improving rural livelihoods and enhancing environmental sustainability. An ex ante financial analysis of the technology was undertaken to assess its economic viability. Input–output data were collected from farmer experiments over three seasons and supplemented with data from traditional cocoa fields of varying rotation ages, and secondary data on production in later years of an eighty-year cocoa rotation. A discounted cash flow analysis was carried out to estimate the benefit-cost (B/C) ratio, net present value (NPV), internal rate of return (IRR) and land expectation value (LEV) as well as the sensitivity to a 20% decline in cocoa prices and additional chemical costs for various shade scenarios at a 10% discount rate. It was observed that cocoa production is, in general, profitable. The change from the traditional system to one with hybrid cocoa raised the IRR from 31% to 57% with planted shade and 67% without, although extra agrochemical costs would tend to reduce the profitability of unshaded hybrid cocoa in particular. The age of maximum LEV for the various scenarios suggests that the optimum economic rotation for the hybrid cocoa is between 18 and 29 years, much less than the traditional system.     

Modeling the effects of climate change and management on the dead wood dynamics in boreal forest plantations

The present research examines the joint effects of climate change and management on the dead wood dynamics of the main tree species of the Finnish boreal forests via a forest ecosystem simulator. Tree processes are analyzed in stands subject to multiple biotic and abiotic environmental factors. A special focus is on the implications for biodiversity conservation thereof. Our results predict that in boreal forests, climate change will speed up tree growth and accumulation ending up in a higher stock of dead wood available as habitat for forest-dwelling species, but the accumulation processes will be much smaller in the working landscape than in set-asides. Increased decomposition rates driven by climate change for silver birch and Norway spruce will likely reduce the time the dead wood stock is available for dead wood-associated species. While for silver birch, the decomposition rate will be further increased in set-aside in relation to stands under ordinary management, for Norway spruce, set-asides can counterbalance the enhanced decomposition rate due to climate change thereby permitting a longer persistence of different decay stages of dead wood.     

Land-use system modeling and analysis of shaded cacao production in Belize

Shaded cacao (Theobroma cacao) cultivation is a tropical land-use that has potential to reduce pressure on the forest and provide additional income to smallholder growers. A land-use system (LUS) model was formulated to represent the economic returns derived from shaded cacao production practiced by smallholders in the Toledo district of Belize. Sixty scenarios were tested to elicit response of net-present-value (NPV), returns to labor, and annual returns to land (ARTL) to individual changes in 10 system parameters. Further scenarios tested the combined interactions between hardwood shade tree type, planting density, time to harvest hardwoods, cacao cultivation practice, and expected output. As a modeling exercise, LUS analysis highlights system components that government agencies, donors, NGOs, extension agents, and smallholders should target with policies, agri-silvi- culture projects, and further research. Results identify more favorable credit, labor-saving technology, better shade-management practices, grafting, and incorporating non-hardwood shade trees and laurel (Cordia alliadora) as interventions that could improve cacao financial performance and encourage adoption. At present, the model cannot predict whether smallholders would respond to recommendations and invest in shaded cacao cultivation in lieu of alternative agricultural land-uses or off-farm employment.     

A comparison of several indices for assessing body condition of Mongolian gazelle

Introduction7Riney(1982)statedthatbodyphysicalconditionofanimalsrespondquicklytoenvironmentalchangesandprovideagoodindextoapopulation'sresponsetothesechangesafterminimaltime-lag,thusfacilitatingamorepreciseunderstandingofcause-effectinterrelationsbetweenanimalsandtheirenvironment.Inthisregard,ameasurementoffatreservesprovidesthebestindextothephysicalconditionofawiderangeofmammal(Riney1955).Formeasuringcarcassfat,variousmethodshavebeendevisedandproposed.Thesemethodsincludekidneyfatindex,bonema…     

Variations in condition and body constitution in a tropical estuarine fish with year-round recruitment

Fish condition (Fulton's K) and the abundance of biochemical constituents (water, protein, lipid and carbohydrate) of juveniles of the tropical estuarine fish, Ambassis vachelli, were monitored over a 15 month period. Fulton's K and biochemical constituents of juveniles recruiting into the adult habitat varied significantly throughout the study. Correlations between Fulton's K and all biochemical measures were weak, with a maximum correlation of 0.1379 (with protein abundance). Significant differences in condition and body constitution of individuals suggest that juveniles recruiting into the adult habitat are not in equal condition and therefore survivorship and success may vary within and among cohorts. Temperature (and salinity) display greater variation in tropical estuarine waters than in other tropical waters and are likely to play a role in determining recruit condition and body constitution. However, the exact role of physical parameters in determining condition and body constitution of fishes is still unknown.     

Integration of animals in rubber plantations

This paper describes a rather unique agroforestry approach of integrating animals (sheep, poultry and bees) in smallholder rubber plantations. The approach is based on the existence of surplus family labour, utilization of interspaces between the rows of rubber, availability of cheap and nutritious animal feed and presence of favourable microclimate for animal growth under rubber. Results of trials carried out by the Rubber Research Institute of Malaysia since the 1970's are presented.Rotational system of broiler production under rubber was found to be technically, socially and economically feasible, providing a net return on family labour of M$370–M$825 per consignment of rearing 500 birds. Sheep rearing under rubber also appeared to be very attractive and practical; apart from producing meat for sale it also served as a biological weed control measure. Cost of controlling the weeds commonly found under rubber plantations could be reduced by about 21% over the usual method by using sheep grazing for weed control. The Internal Rate of Return (IRR) from sheep rearing can be as high as 44%. Details of operation and management aspects of sheep integration under rubber are given.Bees kept under rubber feed on nectar produced by inflorescence and tips of young rubber shoots and also on flowers of intercrops and weeds. TheApis cerana species was found to be suitable producing about 3 kg of honey per colony per harvest.     

Use of hydrogels in the planting of industrial wood plantations

The quantity of available water in soil is crucial for plant growth, especially after transplanting as this water will enable the growth of new roots to facilitate nutrient and water uptake. Water absorbed by a hydrogel (superabsorbent polymer) has the potential to reduce drought stress after planting and to improve seedling survival. This article provides an overview of the concepts of post-plant water stress, a review of trials that tested application of hydrogels to forest tree species, and discussion on probable reasons for failure or success in the use of hydrogels. Hydrogels applied in pot trials, under controlled conditions, tended to have a higher frequency of positive survival responses compared with field trials (14 studies of the 17 (82%) in pot trials vs 15 of the 25 (60%) in field trials). In field trials, the application of hydrogels at planting had no effect on survival in seven of the 25 (28%) trials and had a negative effect in three of the 25 (12%) field trials included in this review. In the trials showing a positive response a hydrogel and water application improved survival by 18% and across all trials by 8%. The efficiency of hydrogels was probably influenced by the (1) chemicals present in the soil, (2) hydrogel quantity applied, (3) type of polymer, (4) hydrogel particle size distribution, (5) soil texture, (6) physical restrictions to hydrogel expansion, (7) hydrophilic nature of hydrogels, (8) unsaturated hydraulic conductivity between the substrate and the hydrogel particles, (9) application method and (10) planting conditions and rewatering. Due to this complexity and interactions between these factors it is difficult to provide site-specific recommendations for successful application of hydrogels in a forestry field setting. In general, application of hydrogels has been found to be more beneficial in sand or clay soils and to be of limited benefit in loam soils. Use of a hydrogel is not a replacement for good silviculture and has limited use as insurance against short periods of low rainfall. All efforts should be made to plant when environmental conditions are favourable for tree growth (i.e. wet soil and high probability of rainfall).     

Preliminary trials of the BioBaler working in Brazilian eucalypt plantations

The increasing demand for renewable energy feedstock has raised interest in growing eucalypts for fuel wood production, which is achieved by establishing very dense plantations cut every 18–24 months. The high moisture content of fresh Eucalyptus may handicap cut-and-chip operations, and offers a unique opportunity for supply chains based on baling. Therefore, the Canadian-made BioBaler was tested in Brazil on a eucalypt energy plantation, as well as on the resprouts generated by a conventional pulpwood plantation after severe frost damage. The BioBaler coped well with both crops, achieving high productivity levels: 7.1 and 3.3 t h^?1 in the energy plantation and the failed crop treatments, respectively. Harvesting cost was estimated at €13 t^?1 and €26 t^?1 for the energy plantation and the failed crop, respectively. Productivity and harvesting cost were comparable with those reported in previous studies conducted in other countries on similar crops. Productivity was directly proportional to field stocking. Future studies should test the machine on a wider range of work conditions and include bale extraction, storage, processing and transportation, in order to estimate an overall supply chain cost and allow direct comparison with alternative options.     

桉树人工林的防火措施探讨

分析了广西桉树人工林的火险特点,简述桉树人工林的防火措施,重点介绍造林过程中采取化学除草,既可抚育又可防火的措施。     

Identification of the Armillaria root rot pathogen in Ethiopian plantations

Armillaria root rot is a well‐known disease on a wide range of plants, world‐wide. In Ethiopia, the disease has previously been reported on Pinus spp., Coffea arabica and on various native hardwoods. The causal agent of the disease has been attributed to Armillaria mellea, a species now known to represent a complex of many different taxa. The aim of this study was to determine the extent of Armillaria root rot and the identity of the Armillaria sp. in Ethiopian plantations. As part of a plantation disease survey in 2000 and 2001, samples were collected in plantations at and around Munessa Shashemene, Wondo Genet, Jima, Mizan and Bedele, in south and south‐western Ethiopia. Basidiocarps were collected and their morphology studied. Morphological identification was confirmed by sequencing the intergenic spacer (IGS‐1) region of the ribosomal rRNA operon and comparing data with published sequences of Armillaria spp. Armillaria isolates were collected from Acacia abyssinica, Pinus patula, Cedrela odorata and Cordia alliodora trees. Sporocarps were found on stumps of native Juniperus excelsa. Basidiocarp morphology and sequence data suggested that the fungus in Ethiopia is similar to that causing disease of Pinus spp. in South Africa and previously identified as A. fuscipes. This identification was confirmed for all isolates, based on sequence data. Armillaria fuscipes is known to be common in southern Africa. Its widespread occurrence in Ethiopia suggests that it is also the major cause of Armillaria root rot in that country.