Model performance of tree height-diameter relationships in the central Congo Basin

Key message

Tree heights in the central Congo Basin are overestimated using best-available height-diameter models. These errors are propagated into the estimation of aboveground biomass and canopy height, causing significant bias when used for calibration of remote sensing products in this region.

Context

Tree height-diameter models are important components of estimating aboveground biomass (AGB) and calibrating remote sensing products in tropical forests.

Aims

For a data-poor area of the central Congo Basin, we quantified height-diameter model performance of local, regional and pan-tropical models for their use in estimating AGB and canopy height.

Methods

At three old-growth forest sites, we assessed the bias introduced in height estimation by regional and pan-tropical height-diameter models. We developed an optimal local model with site-level randomizations accounted for by using a mixed-effects modeling approach. We quantified the error propagation of modeled heights for estimating AGB and canopy height.

Results

Regional and pan-tropical height-diameter models produced a significant overestimation in tree height, propagating into significant overestimations of AGB and Lorey’s height. The pan-tropical model accounting for climatic drivers performed better than the regional models. We present a local height-diameter model which produced nonsignificant errors for AGB and canopy height estimations at our study area.

Conclusion

The application of general models at our study area introduced bias in tree height estimations and the derived stand-level variables. Improved delimitation of regions in tropical Africa with similar forest structure is needed to produce models fit for calibrating remote sensing products.

     

Dental wear in horses in relation to the microhardness of enamel and dentine.

The microhardness of enamel, primary dentine and secondary dentine was determined in the incisor teeth of 39 horses of three different breeds, trotter horses, Belgian draft horses and Arab horses. Using a microhardness tester fitted with a Knoop diamond indenter, the overall Knoop Hardness Number was determined for each tissue, and the influence of breed and age on the hardness were evaluated. Enamel and secondary dentine were significantly harder in Arab horses than in trotters and Belgian draft horses, but there were no significant differences between draft horses and trotter horses in the hardness of their enamel and dentine.     

Influence of agricultural adjuvants on droplet spectra

The formation of a spray is the result of interaction between the nozzle type and the spray liquid. When adjuvants lower the surface tension, a shift to a finer spray quality might be expected. Increases in viscosity might cause coarser sprays. The spray pressure, nozzle type and spray liquid determine spray performance. Adjuvants that cause droplets of oil in the spray mixture, for example crop oils, petroleum oils and even some water-insoluble emulsifiers and surfactants, may unexpectedly increase the spray droplet size. In cases where a finer spray is obtained, the volume fraction of drops smaller than 100 microm diameter, V(100), is expected to increase, but for some adjuvants a decrease in V(100) is observed. Finally, spray droplets may also differ when the concentration of the applied adjuvants changes. An overview based on reports in the literature is given of the effects of different classes of adjuvants used for agricultural cropping on spray droplet spectra. The effects of these adjuvants on spray formation depend on the type of nozzle in combination with the applied pressure.     

Some rheological properties of sodium caseinate-starch gels

The influence of sodium caseinate on the thermal and rheological properties of starch gels at different concentrations and from different botanical sources was evaluated. In sodium caseinate-starch gels, for all starches with the exception of potato starch, the sodium caseinate promoted an increase in the storage modulus and in the viscosity of the composite gel when compared with starch gels. The addition of sodium caseinate resulted in an increase in the onset temperature, the gelatinization temperature, and the end temperature, and there was a significant interaction between starch and sodium caseinate for the onset temperature, the peak temperature, and the end temperature. Microscopy results suggested that sodium caseinate promoted an increase in the homogeneity in the matrix of cereal starch gels.     

Variation of inflammatory dynamics and mediators in primiparous cows after intramammary challenge with Escherichia coli

ABSTRACT: The objective of the current study was to investigate (i) the outcome of experimentally induced Escherichia coli mastitis in primiparous cows during early lactation in relation with production of eicosanoids and inflammatory indicators, and (ii) the validity of thermography to evaluate temperature changes on udder skin surface after experimentally induced E. coli mastitis. Nine primiparous Holstein Friesian cows were inoculated 24 ± 6 days (d) after parturition in both left quarters with E. coli P4 serotype O32:H37. Blood and milk samples were collected before and after challenge with E. coli. The infrared images were taken from the caudal view of the udder following challenge with E. coli. No relationship was detected between severity of mastitis and changes of thromboxane B2 (TXB2), leukotriene B4 (LTB4) and lipoxin A4 (LXA4). However, prostaglandin E2 (PGE2) was related to systemic disease severity during E. coli mastitis. Moreover, reduced somatic cell count (SCC), fewer circulating basophils, increased concentration of tumor necrosis factor-α (TNF-α) and higher milk sodium and lower milk potassium concentrations were related to systemic disease severity. The thermal camera was capable of detecting 2-3°C temperature changes on udder skin surface of cows inoculated with E. coli. Peak of udder skin temperature occurred after peak of rectal temperature and appearance of local signs of induced E. coli mastitis. Although infrared thermography was a successful method for detecting the changes in udder skin surface temperature following intramammary challenge with E. coli, it did not show to be a promising tool for early detection of mastitis.     

Rhinoscopic diagnosis of Eucoleus boehmi infection in a dog

A dog presenting for chronic purulent nasal discharge was diagnosed with an Eucoleus boehmi infection based upon rhinoscopic appearance of the nasal worms in situ, identification of the adult parasites in rhinoscopic nasal biopsies, and ova in the feces. The dog was successfully treated with a 2 wk course of fenbendazole and measures preventing reinfection through coprophagia. Patients with chronic nasal discharge should have a fecal examination performed to rule out infection with E. boehmi.     

Replication characteristics of porcine reproductive and respiratory syndrome virus (PRRSV) European subtype 1 (Lelystad) and subtype 3 (Lena) strains in nasal mucosa and cells of the monocytic lineage: indications for the use of new receptors of PRRSV (Lena)

Recently, it has been demonstrated that subtype 3 strains of European type porcine reproductive and respiratory syndrome virus (PRRSV) are more virulent/pathogenic than subtype 1 strains. This points to differences in the pathogenesis. In the present study, a new polarized nasal mucosa explant system was used to study the invasion of the low virulent subtype 1 PRRSV strain Lelystad (LV) and the highly virulent subtype 3 PRRSV strain Lena at the portal of entry. Different cell types of the monocytic lineage (alveolar macrophages (PAM), cultured blood monocytes and monocyte-derived dendritic cells (moDC)) were enclosed to examine replication kinetics of both strains in their putative target cells. At 0, 12, 24, 48 and 72 hours post inoculation (hpi), virus production was analyzed and the infected cells were quantified and identified. Lena replicated much more efficiently than LV in the nasal mucosa explants and to a lesser extent in PAM. Differences in replication were not found in monocytes and moDC. Confocal microscopy demonstrated that for LV, almost all viral antigen positive cells were CD163⁺Sialoadhesin (Sn)⁺, which were mainly located in the lamina propria of the respiratory mucosa. In Lena-infected nasal mucosa, CD163⁺Sn⁺, CD163⁺Sn^- and to a lesser extent CD163^-Sn^- monocytic subtypes were involved in infection. CD163⁺Sn^- cells were mostly located within or in the proximity of the epithelium. Our results show that, whereas LV replicates in a restricted subpopulation of CD163⁺Sn⁺ monocytic cells in the upper respiratory tract, Lena hijacks a broader range of subpopulations to spread within the mucosa. Replication in CD163⁺Sn^- cells suggests that an alternative entry receptor may contribute to the wider tropism of Lena.     

Stored water use and transpiration in Scots pine: a modeling analysis with ANAFORE

We estimated daily use of stored water by Scots pine (Pinus sylvestris L.) trees growing in a temperate climate with the ANAFORE model (ANAlysis of FORest Ecosystems) and compared the simulation results with sap flow measurements. The original model was expanded with a dynamic water flow and storage model that simulates sap flow dynamics in an individual tree. ANAFORE was able to accurately simulate diurnal patterns of measured sap flow under microclimatic conditions that differ from those of the calibration period. Strong relationships were found between stored water use and several tree characteristics (diameter at breast height, sapwood area, leaf area), but not with tree height. Relative to transpiration, stored water use varied over time (between < 1% and 44% of daily transpiration). On days when transpiration was high, trees were more dependent on stored water, indicating that the contribution of internal water to transpiration is not a constant in the water budget of trees.     

The ossification of cartilages of the distal phalanx in the horse: An anatomical, experimental, radiographic and clinical study

This paper describes some anatomical findings relatedto ossification of the distal phalanx cartilages by anatomical and computerized tomographic sections. Radiographic findings of ossification were analyzed and correlated to age and breed. Ossification was found in 10% of warmblood horses and in 80% of draft horses and was much more severe in draft horses than in warmblood horses. The expansion of the hoof was measured in the laboratory in several feet of warmblood and draft horses and was found to be minimal with no differences whether ossification was present or not. Computerized tomography was performed on a foot of a slaughtered horse before and after up to 7000N loading in the laboratory in order to study the eventual changes of the cartilages and the hoof. These structures seemed quite unaffected by the load and expansion of the horny capsule was minimal. Minor expansion seems an inevitable structural behavior of the hoof and the classical hoof mechanism is questioned. The clinical significance of ossification in its relation to lameness was individually determined during clinical examination and by comparison of groups of horses with and without ossification with groups of horses with lameness from the foot and proximal to the foot. The severity of the ossification was related to the onset of lameness and no correlation was found. It is concluded that the clinical significance of ossification is almost nil. Ossification is not painful when developing and not thereafter. There is no correlation between navicular disease and ossification of the cartilages either. Orthopedic shoeing is of no significance at all. An unfavorable advice in purchase examinations in sporting horses due to cartilage ossification is not justified in the author's opinion.