Effect of cultural practices on the development of arabica coffee berry disease,caused by <Emphasis Type="Italic">Colletotrichum kahawae</Emphasis>

In the high altitude regions of Africa, coffee berry disease (CBD), caused by Colletotrichum kahawae, is the main constraint for arabica coffee (Coffea arabica) production. However, certain agricultural practices can reduce losses caused by the disease and thereby promote optimum production. On small family farms in Cameroon, mixed cropping with fruit trees, intercropping with food crops and maintenance pruning of coffee trees are very widespread agricultural practices that can affect CBD epidemics. Consequently, an epidemiological study was conducted to assess how cultural practices affected the disease in an arabica coffee smallholding in Cameroon. The disease was monitored on a weekly basis over four successive years (2002–2005) on coffee trees in diverse cultural situations. Cultural practices likely to reduce losses due to CBD were identified. The infection rate was significantly lower on coffee trees grown intensively than on coffee trees grown in the traditional manner. Coffee trees located under the shade of fruit trees were significantly less attacked than those located in full sunlight. In addition, berries on the leafless parts of branches, near the main trunk of the coffee tree, were less infected than those on leafy sections. These results show that maintenance pruning, removal of mummified berries, and mixed cropping with shade plants are cultural practices which create environmental conditions that limit CBD development.     

Landscape labelling: A concept for next-generation payment for ecosystem service schemes

Current payment for environmental service (PES) schemes face challenges in the form of evaluation of opportunity costs and ecosystem service delivery, high transaction costs, and difficulties in ensuring conditionality. Even when these conditions are met, PES may be undermined by a lack of inclusivity, leading to societal conflicts over land use. We propose a new PES-type approach that we call Landscape Labelling that seeks to overcome these problems by combining PES and product certification principles applied at a landscape scale with local benefits realized at the community level.     

Water Quality in Laboratory Soil-Water Microcosms with Soils from Different Areas of Thailand

Forty-five soil samples were collected from aquaculture areas in 23 provinces of Thailand to include six soil orders and wide variation in physical and chemical properties. Soil-water microcosms were prepared containing 5 g of soil and 150 mL of distilled water. Microcosms were held on an oscillating table shaker (150 rpm) for 1 wk at 25 C in the dark. Water pH and concentrations of dissolved nutrients, total alkalinity, and total hardness were measured. Differences in properties within soil orders caused wide variation in composition of solutions and differences in concentrations of dissolved substances and pH were not related to soil order. Regression analyses revealed significant correlations between concentrations of soil nutrients extractable in dilute acid (0.05 N HCI plus O.025 N H₂SO₄) or in neutral, 1 N ammonium acetate and aqueous concentrations. Regression coefficients usually were higher for dilute-acid extractable nutrients than for ammonium acetate extractable ones. Regression coeficients based on dilute-acid extractable nutrients follow: soluble reactive phosphorus ( r = 0.816); calcium ( r = 0.685); magnesium ( r = 0.470); potassium ( r = 0.959); sodium ( r = 0.977); manganese ( r = 0.462); boron ( r = 0.399). The correlation between soil and solution iron was not significant and aqueous concentrations of copper and zinc were below detection limit. Hardness was correlated with soil carbon ( r = 0.710) and soil pH was a good predictor of alkalinity ( r = 0.877). Soil pH and aqueous pH were highly correlated (r = 0.939). Findings suggest that soil characteristics can be used to predict pH and concentrations of several dissolved substances in soil-water systems under aerobic conditions.     

A variance-covariance structure to take into account repeated measurements and heteroscedasticity in growth modeling

This study proposes a within-subject variance-covariance (VC) structure to take into account repeated measurements and heteroscedasticity in a context of growth modeling. The VC structure integrates a variance function and a continuous autoregressive covariance structure. It was tested on a nonlinear growth model parameterized with data from permanent sample plots. Using a stand-level approach, basal area growth was independently modeled for red spruce (Picea rubens Sarg.) and balsam fir [Abies balsamea (L.) Mill.] in mixed stands. For both species, the implementation of the VC structure significantly improved the maximum likelihood of the model. In both cases, it efficiently accounted for heteroscedasticity and autocorrelation, since the normalized residuals no longer exhibited departures from the assumptions of independent error terms with homogeneous variances. Moreover, compared with traditional nonlinear least squares (NLS) models, models parameterized with this VC structure may generate more accurate predictions when prior information is available. This case study demonstrates that the implementation of a VC structure may provide parameter estimates that are consistent with asymptotically unbiased variances in a context of nonlinear growth modeling using a stand-level approach. Since the variances are no longer biased, the hypothesis tests performed on the estimates are valid when the number of observations is large.     

The dehesa: an agrosilvopastoral system of the Mediterranean region with special reference to the Sierra Morena area of Spain

A multidisciplinary team undertook a six-year investigation on the agro-ecological and socio-economic aspects of the dehesa system in the Sierra Norte area, a part of the Sierra Morena of the Sevilla Province, Western Andalusia, Spain. This paper summarizes its findings on the various agro-ecological features of the system and evaluates the system's functional aspects vis-a-vis the trends and developments in land use in the region over the past few centuries. The synergistic effects of tree cover on understorey grassland vegetation is discussed in terms of soil fertility build-up and favourable micro-climatic and hydrological features, and the potential use of this information in future research and development programmes to improve the dehesa system in the Mediterranean region is outlined.     

Impact of fertilization on tree-ring delta15N and delta13C in beech stands: a retrospective analysis

We studied the effects of two fertilization treatments (N and NPKCa) on wood nitrogen (N) isotope composition (delta(15)N), water-use efficiency (WUE) estimated by carbon isotope composition (delta(13)C) analyses, and ring width of trees in 80-year-old beech (Fagus sylvatica L.) stands in the forest of Fougères, western France. Four replicates were fertilized in two successive years (1973 and 1974), 20 years before core sampling. Unfertilized control trees displayed a decreasing delta(15)N trend with time. The N and NPKCa treatments both increased delta(15)N compared with the control treatment. Wood extraction by organic solvents enhanced the delta(15)N signal. Thus, N addition to the beech ecosystem, even in moderate amounts, could be traced back in tree-ring delta(15)N, suggesting that wood N isotope analysis is a promising tool for studying the long-term effects of N deposition on forests. Although WUE decreased for about 6 years after N fertilization, WUE in NPKCa-treated trees did not differ significantly from that in control trees. Results were similar whether based on cellulose or total wood delta(13)C analysis, suggesting that extraction of cellulose is not necessary when studying fertilization impacts on WUE. The NPKCa treatment had a large impact on radial growth, causing a significant long-lasting increase of 29% compared with the control treatment. Nitrogen alone did not change radial growth significantly.     

Do trees use reserve or newly assimilated carbon for their defense reactions? A 13C labeling approach with young Scots pines inoculated with a bark-beetle-associated fungus (Ophiostoma brunneo ciliatum)

Three-year-old saplings of Pinus sylvestris L. were labeled with ¹³CO₂ prior to inoculating the trunk with Ophiostoma brunneo ciliatum, a blue-staining fungus usually associated to Ips sexdentatus. During incubation, half the trees were submitted to a severe drought that decreased photosynthesis and natural ¹³C content in non-labeled saplings. A large ¹³C-excess was obtained in wood and phloem, especially in the fractions of soluble proteins, starch and soluble sugars of labeled saplings. Drought increased ¹³C-excess, due to reduced photosynthesis and smaller dilution of ¹³C by the addition of newly assimilated ¹²C. The induced-reaction zones in inoculated saplings displayed large total C (58 g 100 g^?1) because of the accumulation of secondary metabolites. They also showed much larger ¹³C-excess than any other compartment: the contribution of stored C to the reaction zones was much higher than that of currently assimilated C. Moreover, drought lowered the contribution of the latter, as shown by the increase of ¹³C in the reaction zones. We conclude that stored C was readily mobilized for the construction of reaction tissues, and that the contribution of currently assimilated C was only minor.     

Estimates of stem wood increments in forest resources: comparison of different approaches in forest inventory: consequences for international reporting: case studyof European forests

Key message

Quality and reliability of forest resource assessments depend on the ability of national forest inventories (NFIs) to supply necessary and high-quality data. Over the last decades and especially since the 1990s, the NFIs in European countries have been rapidly developing. Possibilities for obtaining reliable and accurate data on annual increment from different inventory types were evaluated, and sample-based inventories have been found to be superior to standwise inventories in providing reliable data. Simplified methods may be employed when increment cannot be directly estimated from inventory data.

Context

An increasing intensity of forest resource use requires more accurate, detailed and reliable information, not only on forest area and growing stock but also on forest stand productivity, wood increment and its components.

Aims

The main objectives were to assess the capacities of forest inventories, the methods used for estimation of gross increment and its components and their accuracy and to demonstrate an effective method for estimation of increment when direct inventory methods are not available.

Methods

Data about national forest inventory methods were obtained from 30 responses to a questionnaire, distributed amongst national correspondents of all European countries; reports of COST Actions E43 and FP 1001, databases of Temperate and Boreal Forest Resource Assessment (TBFRA) 2000 and State of Europe’s Forests (SoEF) 2011 were used as well. Analysis and comparison of results from different forest inventories were used for evaluation of data reliability. Relationships between growing stock and gross increment in European forests were also analysed, and corresponding models were proposed.

Results

Seventy-nine percent of European forest area is covered by national forest inventories (NFIs) based on sampling methods and the rest on stand-level inventory and other inventory methods. Data obtained by aggregating standwise data usually underestimate growing stock by 15–20 % and gross increment even more. Almost half of the European forest area (47 %) is monitored using permanent plots, measured twice or more, allowing the estimation of gross increment and its components to be made directly.

Conclusion

Implementation of NFIs based on sampling methods, especially with permanent plots, resulted in an improvement of data quality and in most cases an increase of growing stock and gross increment. The estimation of natural losses is the weakest link in today’s NFIs and in the current assessment of European forest resources. The proposed default values for gross increment and its components is an option to be used in countries not having NFI at all or those which have started it only recently.

     

Antibacterial and antioxidant activities of Artemisia annua essential oil

The essential oil of Artemisia annua aerial parts, consisting of camphor (44%), germacrene D (16%), trans-pinocarveol (11%), beta-selinene (9%), beta-caryophyllene (9%) and artemisia ketone (3%), was screened for its antimicrobial activity. The essential oil remarkably inhibited the growth of tested Gram-positive bacteria Enterococcus hirae and both tested fungi. This oil has shown an antioxidant activity equivalent to 18% of the reference compound (alpha-tocopherol).