Soil properties under a Pinus radiata – ryegrass silvopastoral system in New Zealand. Part II. C and N of soil microbial biomass, and soil N dynamics

At present, our understanding of the dynamics of microbial biomass and soil N in silvopastoral systems is very limited. In this paper, the effects of understorey management on soil microbial C and N, net N mineralization, and net nitrification were studied in two seven-year-old radiata pine (Pinus radiata D. Don) – pasture systems, consisting of plots with and without ryegrass (Lolium perenne) as an understorey. Mini-plots (1 × 1 m) with animals excluded and herbage repeatedly clipped and removed were used for soil sampling. Three mini-plots formed a transect at each of two positions: 0.9 and 3.5 m north of the tree rows. Measurements were taken from July 1997 to June 1998 about once every 40 days. One composite sample was collected from each of two sampling depths (0–10 and 10–20 cm) at each transect position on each sampling date. Temporal and spatial variability of N mineralization rates and microbial biomass C and N was large. Net mineralization and nitrification rates were higher in the bare ground than in the ryegrass plots for a major part of the year, particularly from late spring to early fall. Net N mineralization and nitrification rates were higher in the 0–10 than in the 10–20 cm soil layers in both the ryegrass and bare ground treatments; however, the depth effect on microbial biomass C and N was only significant in the ryegrass treatment. In the surface soil layer, microbial biomass C and N were substantially greater in the ryegrass than in the bare ground plots. Soil microbial properties and activities were closely linked to pasture root activities, soil depth, and site biophysical conditions. This revised version was published online in June 2006 with corrections to the Cover Date.     

Cucubalugenin A, a new triterpenoid from Cucubalus baccifer.

A new triterpenoid, cucubalugenin A (1), has been isolated from the whole plant of Cucubalus baccifer. Its structure was elucidated by spectral methods.     

Application of modal analysis by transfer function to nondestructive testing of wood II: modulus of elasticity evaluation of sections of differing quality in a wooden beam by the curvature of the flexural vibration wave

 The shape of the flexural vibration wave of wooden beams at the first mode was detected using the transfer function. The dynamic modulus of elasticity (MOE) of beam sections of differing quality was estimated from the ratio of the curvature of the wave shape in this section to that of a clear beam. The results were as follows: (1) If a section with a lower dynamic MOE was introduced into a clear wooden beam, the curvature of the wave shape in that section became higher. (2) The ratio of the MOE and the reciprocal of the curvature ratio were highly correlated. (3) The MOE of a defect could be estimated, and the position of the defect could be determined accurately by examining the curvature of the flexural vibration wave shapes. Received: March 22, 2002 / Accepted: May 15, 2002 Part of this report was presented at the 50th Annual Meeting of the Japan Wood Research Society, Kyoto, April 2000. This article is translated from the Japanese version, which was published in Mokuzai Gakkaishi 47(5), 2001 Correspondence to:Y. Ishimaru     

Root carbohydrate reserves, mineral nutrient concentrations and biomass in a healthy and a declining sugar maple (Acer saccharum) stand

Soil and root characteristics were contrasted between a "declining" and a "healthy" sugar maple (Acer saccharum Marsh.) stand in Vermont, USA. The declining stand had lower basal area increment and more crown dieback than the healthy stand. Soil pH and base cation content were lower and soil water content was higher at the site of the declining stand than at the site of the healthy stand, whereas soil temperature did not differ significantly between the sites. In live fine roots, concentrations of K and Ca were marginally (P < 0.07) lower in the declining than in the healthy stand, whereas concentrations of N, P, Mg, and Al were not significantly different (P = 0.13 to 0.87) between stands. Starch and soluble sugar concentrations of fine and coarse roots did not differ significantly between stands, indicating that crown dieback did not affect carbohydrate supply to the roots in the declining stand. Throughout the growing season, the standing live and dead root biomass were significantly higher in the declining stand than in the healthy stand, indicating that more carbon was allocated to roots and that root turnover was higher in the declining stand than in the healthy stand.     

Consumer willingness to pay price premiums for environmentally certified wood products in the U.S.

Since its inception nearly 15 years ago, environmental certification has become an important issue in the wood products industry. One research question that has been examined is the potential willingness for supply chain participants to pay a premium for certified products or raw materials to offset certification costs. This study examines stated willingness to pay for four wood products from the perspective of U.S. consumers. Data was collected in 1995 and 2005 from the population of U.S. residential consumers to detect changes in willingness to pay for certified wood products along time and increase the statistical strength of the model. Results of an ordered probit model suggest that higher probabilities of paying a premium are associated to consumers who seek out certified products and who believe certification can lessen environmental impacts such as tropical deforestation. There is also a strong relationship between respondent income and willingness-to-pay. Despite the current industry structure in the U.S. that has adopted a mass-certification strategy that does not place price premiums on certified products, results suggest that such premiums may exist for imported certified tropical wood products. Analysis of marginal effects suggests consumers' willingness to pay a 10% premium for three of the four certified items studied. Niche markets may potentially be exploited in the U.S. and price premiums captured by wood products manufacturers in tropical regions and/or American importers.     

Efficiency of early selection for rotation-aged wood quality traits in radiata pine

A total of 360 bark-to-bark-through-pith wood strips were sampled at breast height from 180 trees in 30 open-pollinated families from two rotation-aged genetic trials to study inheritance, age-age genetic correlation, and early selection efficiency for wood quality traits in radiata pine. Wood strips were evaluated by SilviScan® and annual pattern and genetic parameters for growth, wood density, microfibril angle (MFA), and stiffness (modulus of elasticity: MOE) for early to rotation ages were estimated. Annual ring growth was the largest between ages 2–5 years from pith, and decreased linearly to ages 9–10. Annual growth was similar and consistent at later ages. Wood density was the lowest near the pith, increased steadily to age 11–15 years, then was relatively stable after these ages. MFA was highest (35°) near the pith and reduced to about 10° at age 10–15 years. MFA was almost unchanged at later ages. MOE increased from about 2.5 GPa near the pith to about 20 GPa at ages 11–15 years. MOE was relatively unchanged at later ages. Wood density and MOE were inversely related to MFA. Heritability increased from zero near the pith and stabilised at ages 4 or 5 for all four growth and wood quality traits (DBH, density, MFA and MOE). Across age classes, heritability was the highest for area-weighted density and MFA, lowest for DBH, and intermediate for MOE. Age-age genetic correlations were high for the four traits studied. The genetic correlation reached 0.8 after age 7 for most traits. Early selection for density, MFA and MOE were very effective. Selection at age 7–8 has similar effectiveness as selection conducted at rotation age for MFA and MOE and at least 80% effective for wood density.     

Expansion of the aphid Myzocallis (Lineomyzocallis) walshii (Monell) on the red oak Quercus rubra, and adaptation of local parasitoids in the northeastern Iberian Peninsula (Hom., Aphididae, Calaphidinae; Hym., Braconidae, Aphidiinae)

An ongoing expansion of Myzocallis (L.) walshii (Monell) in the NE Iberian Peninsula was detected. The aphid species was recorded in Catalonia, Andorra and Navarra. Adaptation of local native parasitoids (at least Trioxys pallidus Haliday and T. tenuicaudus Stary) to the new immigrant was documented, together with background information on their host range in the native environments. The detection of parasitoids of M. walshii is the first published evidence in Europe. The new evidence for M. walshii in the NE Iberian Peninsula also supports the warning of the expansion of the aphid as a pest of Quercus rubra over Europe.     

Dosage assessment of valnemulin in pigs based on population pharmacokinetic and Monte Carlo simulation

To estimate the valnemulin pharmacokinetic profile in a swine population and to assess a dosage regimen for increasing the likelihood of optimization. This study was, respectively, performed in 22 sows culled by p.o. administration and in 80 growing‐finishing pigs by i.v. administration at a single dose of 10 mg/kg to develop a population pharmacokinetic model and Monte Carlo simulation. The relationships among the plasma concentration, dose, and time of valnemulin in pigs were illustrated as C_i,v = X₀(8.4191 × 10^‐4 × e^?0.2371t + 1.2788 × 10^?5 × e^?0.0069t) after i.v. and C_p.o = X₀(?8.4964 × 10^?4 × e^?0.5840t + 8.4195 × e^?0.2371t + 7.6869 × 10^?6 × e^?0.0069t) after p.o. Monte Carlo simulation showed that T_>MIC was more than 24 h when a single daily dosage at 13.5 mg/kg BW in pigs was administrated by p.o., and MIC was 0.031 mg/L. It was concluded that the current dosage regimen at 10–12 mg/kg BW led to valnemulin underexposure if the MIC was more than 0.031 mg/L and could increase the risk of treatment failure and/or drug resistance.