Effects of residual trees on tree height of 18- and 19-year-old Cryptomeria japonica planted in group selection openings

This study examined the effects of residual trees on the height of 18- and 19-year-old Cryptomeria japonica planted in group selection openings of about 0.1 ha at Yufuin in Oita Prefecture in southern Japan. We first developed a general model expressing variation in the height for all of the planted trees within the openings from indices of both between-cohort competition (the effects of residual trees) and within-cohort competition (among the even-aged planted trees). The between-cohort competition index was calculated both with and without taking into account the direction that residual trees were positioned from subject trees. The two models suggested that residual trees located near the northern edge of the opening were not effective competitors for light for the planted trees within the opening. In addition, our results indicated that both between-cohort competition and within-cohort competition are important for explaining tree height in closed stands within group selection openings. Using the general model, we then estimated the potential loss of height growth for locally dominant trees within the openings that could be attributed only to the influence of residual trees. These results indicated that in addition to the effect of opening size, both the degree of crowding and the direction of residual trees from the planted trees are important factors affecting the height of individual trees planted in group selection openings.     

Evaluation of estimates of crown condition in forest monitoring: comparison between visual estimation and automated crown image analysis

• Context  

In long-term forest monitoring, tree crown condition has been visually rated to diagnose tree vigor and forest condition. However, visual estimates are subjective. A semiautomatic image analysis system, called CROCO, was developed to estimate crown condition quantitatively. CROCO calculates a DSO value which decrease with increasing crown transparency.     

Female infertility in grt mice is caused by thyroid hormone deficiency, not by insufficient TPST2 activity in the reproductive organs

The growth-retarded (grt) mouse has an autosomal recessive hypothyroidism and the female shows lifelong infertility. We previously reported that these mutant phenotypes are caused by a deficiency in the enzymatic activity of tyrosylprotein sulfotransferase-2 (TPST2), and severe thyroid hypogenesis and consequent dwarfism are mainly due to the impairment of the tyrosine sulfation of thyroid-stimulating hormone receptor (TSHR) by TPST2. Although TPST2 is ubiquitously expressed and many proteins are predicted to be tyrosine sulfated and involved in many biological processes, the functional roles of tyrosine sulfation in the reproductive organs remain unclear. These findings tempted us to hypothesize two possible mechanisms underlying the infertility; a deficiency in TPST2 activity in the reproductive organs might cause the infertility in grt mice, or a significant decrease in serum thyroid hormones might impair the normal development of reproductive organs. When mutant female mice were fed a diet supplemented with sufficient thyroid powder to correct their growth retardation, the rate of copulation, pregnancy, and parturition was completely restored. Therefore, we concluded that the infertility in grt female is due to a thyroid hormone deficiency.     

Comparative observation on the growth changes of the histochemical properties and collagen architecture of the Musculus puboischiofemoralis pars medialis from Silky, layer-type and meat-type cockerels

Growth‐related changes in the histochemical properties and collagen architecture of the Musculus puboischiofemoralis pars medialis were compared among Silky, layer‐type, and meat‐type cockerels. Histochemical and immunohistochemical methods were employed and collagen architecture was studied using scanning electron microscopy. Total intramuscular collagen was also determined. The myofibers were categorized as type I, type IIA and a transitional form, type I‐tr. The proportion of type I‐tr myofibers diminished and these myofibers were transformed entirely into type I myofibers in meat‐type but incompletely in the others. The largest diameter of type I myofiber was found in layer‐type at 30 weeks of age. At 30 weeks of age, layer‐type birds had attained well‐developed perimysial collagen bundles while meat‐type birds had less developed bundles. The endomysial collagen network had a large mesh size at 1 week and then accumulated many collagen fibrils to form a felt‐like fabric of fibrils by 30 weeks of age. Silky birds developed the thickest endomysial collagen plates of all the breeds. From these results it appears that growth‐related changes in the histological structure of M. puboischiofemoralis pars medialis are not necessarily causally affected by the different growth rates of chicken breeds.     

Estimating forest biomass increment based on permanent sample plots in relation to woodfuel consumption: a case study in Kampong Thom Province,Cambodia

To assess the sustainability of forest use for woodfuel, above ground biomass increment must be examined against woodfuel consumption. However, reliable data on the biomass increment of tropical forests are very limited. In this study, we estimated above ground forest biomass increment in Kampong Thom Province, Cambodia, using two consecutive measurements of 32 permanent sample plots in 1998 and 2000, and forest inventory data of 540 plots collected in 1997. The permanent sampling plot data were used to determine the relationship between initial biomass and subsequent biomass increment over a 2-year period. This relationship was applied to the inventory data to obtain a robust estimate of biomass increment across the major forest types for the entire province. The weighted average annual above ground biomass increment for the whole province was 4.77Mg/ha, or 2.3% of biomass. Woodfuel consumption was estimated to be about 2% of biomass increment for the province, suggesting that deficiency of woodfuel may not occur in this province. However, localized variation needs to be taken into account and there is a need to examine the effects of stand age and factors such as soil type, microtopography, and species composition on biomass increment and to consider woodfuel collection rate in specific forest areas with respect to accessibility for firewood collection.     

Development and application of West Nile virus subgenomic replicon RNA expressing secreted alkaline phosphatase

We have developed a West Nile virus (WNV) subgenomic replicon harboring the secreted alkaline phosphatase (SEAP) reporter gene instead of viral structural genes (designated repWNV/SEAP). The repWNV/SEAP allowed easy evaluation of viral replication efficiency by direct measurement of SEAP secretion in the cell culture medium in physical containment level 2 facilities. Furthermore, we validated the availability of this system using a known anti-flavivirus gene, mouse oligoadenylate synthetase 1b (Oas1b). The Oas1b-transfected cells were more resistant to repWNV/SEAP replication than the original cells. Thus, this system not only affords a useful tool for identification/evaluation of anti-flavivirus genes/drugs in terms of safety, ease of use and reliability, but should be able to reduce or replace the bioassay using laboratory animals.     

First report of Phytophthora palmivora as a causal pathogen of citrus brown rot in Japan

A fruit rot, similar to brown rot, occurred on extremely early ripening Satsumas in Saga Prefecture in the early autumn of 1999. A single species of Phytophthora was isolated from the affected fruit. After nonwounding inoculation of healthy fruits of Citrus spp. including Satsuma with the isolated fungus, the fungus was reisolated from fruit with symptoms similar to those in nature. On the basis of its morphology and molecular analysis of the rDNA-internal transcribed spacer regions, the pathogen was identified as P. palmivora. This is the first report of P. palmivora as a causal pathogen of citrus brown rot in Japan.