Japan is one of the world’s leading holders of chain of custody (CoC) certificates. Paper products companies have constituted the majority of certificate holders. In this study, we examined the current status and prospect of the Certified Forest Products (CFPs) markets in the construction industry which is the major wood-consuming industry along with the paper industry. A questionnaire survey was conducted in June 2009, and 203 non-certified construction companies located in Tokyo, Osaka, or Aichi Prefecture and 39 CoC-certified companies nationwide responded. Although introduction of environment-friendly wood products (EWPs) was becoming common even among non-certified companies, most of them were interested in recycled or thinned wood as EWPs. In addition, they weren’t familiar with either forest certification or related schemes. Thus, it was unlikely the growing markets of EWPs in the construction industry would lead expansion of CFPs markets immediately. Compared to non-certified companies, certified ones had the following features: they appreciative more of importance of EWPs, they put much emphasis on environmental aspects when they selected wood materials, they had the sole discretion over wood procurement, and had kept track of supply chain of wood products even before they were certified. Improvement of information service system and establishment of supply system were indispensable to expand CFPs markets in the industry.

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To evaluate the possibility of conversion to broadleaf forests from conifer plantations, we searched the literature that was published in Japanese during 1978∼2006 using Japanese Forestry Literature Information System (FOLIS). The literature was searched by the main term broad leaf tree and several sub-words, thinning , cleaning , plantation , etc. The total number of bibliographies and studies were 185 and 648, respectively. Studies were evaluated as S-, A-, B-, and C-ranks according to the level of importance about broadleaf tree regeneration. S-rank studies numbered 14 and A-rank literatures were 59. A regional abundance of studies and historical changes of keywords were discussed with the change of forest management policy in Japan. Studies were abundant on Gifu (16 studies) and Miyazaki (15) Prefectures. The number of studies using the keywords broadleaf tree regeneration or natural regeneration decreased, but studies related to diversity have been increasing recently. The keywords plantation failures and thinning have continued from the 1980s through several peaks. Leading from coniferous forests to broadleaf forests is a new type of operation for most foresters. Such a new operation should be developed carefully.

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By using a predicting model for pollen dispersal of Cryptomeria japonica, which was developed by the present authors, we estimated the Cryptpmeria pollen source areas which have the high contributions to the Japanese metropolitan region. For the evaluation criteria, we used two indices; the average pollen concentration during pollen dispersal period, and the pollen exposure index (pollen concentration multiplied by the population in that area). For the smaller target region which did not contain any pollen source (the region within the 10 km-circle around Tokyo Station, with the population of more than five million people), the similar results were obtained when using both indices. However, for the greater Metropolitan region (90 km from east to west and 80 km from north to south, including Tokyo and Yokohama city, with the population of 30 million people), the pollen sources within this region were estimated to have the extremely high contributions to this region when using the pollen concentration as the evaluation criterion. Moreover, the results of different sample years differed from each other, for both indices for evaluation criteria.

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Cryptomeria japonica D. Don is one of the most commercially important conifers in Japan. However, the allergic disease caused by its pollen is a severe public health problem in Japan. A recent nationwide epidemiological survey found that at least 25% of the Japanese population suffers from pollinosis due to pollen of C. japonica. The primordia of male strobili of C. japonica develop from June to August and first become visible from July to September under natural conditions. The development of strobili can also be initiated by treatment with gibberellic acid (GA3). The promotion of flower formation by exogenous GA3 occurs even in one-year-old seedlings in spite of the fact that formation of strobili usually requires around 20 years after germination under natural conditions. However, development of male strobili and pollen has not been clarified. The Forestry and Forest Products Research Institute has succeeded in the large-scale collection of 10,463 nonredundant full-length enriched cDNA clones of C. japonica male strobili. The cDNA resources contain homologs of stamen- and pollen-specific transcripts of Arabidopsis, and provide new information about potential allergens, putative transcription factors including MADS-box genes and floral meristem identity genes, and male sterility genes in C. japonica. These genes are valuable tools to clarify the development of male reproductive organs. I here introduce a direction of studies on the formation of male strobili, the suppression of formation of male strobili by inhibitors of gibberellin biosynthesis, and flowering control and introduction of male sterility by genetic engineering.

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I reviewed studies relating to sugi (Cryptomeria japonica) pollen and drafted a guideline for foresters on how to reduce sugi pollen through forest management based on the long-term predictions. Since the prevalence of sugi-pollinosis is proportional to the production of sugi pollen per unit of land area at the prefectural level in Japan, reducing sugi trees that produce high levels of pollen is a reasonable target of forest management to mitigate sugi-pollinosis. Thinning and pruning sugi trees are considered a limited means to reduce sugi pollen. According to predictions using a model that simulates sugi pollen production, reducing the cutting period and conversion to sugi pollen-free forests will markedly reduce sugi pollen. An increase in summer temperatures in the 21st century as simulated using a climate change scenario and the influence of thinning practiced as a national policy throughout Japan for mitigating climate change can increase sugi pollen by up to about 10% compared to the baseline scenario. Offsetting this increase may be a target for adapting to the impacts of climate change. Clear-felling sugi forests would be an effective way to curb the increase and would allow the increase to be offset at an earlier date than that of the baseline scenario. Focusing on felling plantations that produce high levels of sugi pollen and avoiding reforestation with such pollen-heavy sugi would also allow the increase in sugi pollen to be offset earlier.

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Japanese cedar (Cryptomeria japonica D. Don) pollinosis has become a serious allergic disease. Therefore, an important issue is to reduce the amount of airborne pollen by breeding method. There was a great difference in male flower setting among plus tree clones. From the investigation in clonal test plantations, 135 clones were selected with few male flowers. The heritability of male flower setting was high at 0.34. Cry j 1 content of 420 plus tree clones showed variation from 0.38 to 10.23 pg per pollen grain and the heritability of Cry j 1 estimated by parent-offspring regression was very high at 1.0. From these results, it was suggested that a large number of seedling with low allergens could be created by crossing the clones selected low pollen allergen. Male sterility of C. japonica is controlled by a recessive allele at a single locus and is expressed only in homozygotes (aa). We selected that 4 plus tree clones that are heterozygous for a male-sterility gene. It is possible to create superior male-sterile trees by crossing with plus trees possessing the male-sterility gene. The use of these pollinosis preventive cultivars would reduce C. japonica pollen production while maintaining the yield of high quality timber.

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