Sugi Forests Research Articles

Development of cultivation method for Leucopaxillus giganteus fruiting bodies in Cryptomeria japonica artificial forests

ABSTRACT Sugi (Cryptomeria japonica) forests are devastated and abandoned in Japan. Although mushroom products are profitable, with the marketable ones expected to originate from Japanese forests, a few fungi mainly develop fruiting bodies in sugi forests in nature. With white mushrooms (Sugi-take) being popularly eaten by local residents in Mie prefecture, it is thus important that the mode of occurrence of white mushrooms found in the forests is investigated to determine the possibility of marketable forest products in sugi forests. In the phylogenetic tree constructed based on the internal transcribed region of rDNA, white mushrooms were divided into two groups; Leucopaxillus giganteus (a synonym of Aspropaxillus giganteus) and Aspropaxillus, and Clitocybe sp. and L. tricolor. The cultivation method of L. giganteus, which is the most functional mushroom among the three species, was examined. L. giganteus fruiting bodies formed a fairy ring at a distance of 1 m from the point of burial of 40 kg media in the sugi forest. L. giganteus fruiting body formation was observed until 5 years post-inoculation. The yield was 3.8–13.4 kg/year and the total yield for 5 years was 43.2 kg. The fruiting body yield buried in spring was higher than that buried in autumn. The highest yield was obtained when 40 kg of media was buried in the forest soil. This study established a method for cultivating L. giganteus in the sugi forest of Japan.

Developing a Method for Interconversion between Omnidirectional Images and Poind Cloud Data in a Sugi Forest

Developing a Method for Interconversion between Omnidirectional Images and Poind Cloud Data in a Sugi Forest

Long observation period improves growth prediction in old Sugi (Cryptomeria japonica) forest plantations

ABSTRACT It is important to predict the growth of Sugi forest plantations in old age. When predictions about the growth of Sugi forest plantations are made and there is a lack of growth data from older trees, it is possible that the accuracy of these predictions becomes worse. For example, it is known that the growth of Sugi does not get slower at older ages as expected from past growth predictions based on growth data from young to middle-aged trees. This study investigated the changes in extrapolated values of diameter at breast height (DBH) in old Sugi forest plantations with changes in the observation period of training data for model calibration. The study sites were long-term growth observation sites of Sugi forest plantations in the University of Tokyo Chiba Forest and Chichibu Forest. In this study, both DBH of individual trees and mean DBH of stands were analyzed by fitting Richards growth functions. The results showed that the accuracy of growth predictions in old ages was improved by including growth data from a sufficient number of older trees. From another point of view, growth prediction in old ages tended to underestimate actual growth if growth data did not include enough older trees.

Dynamic state of the floor vegetation in a fire-damaged sugi forest in Tottori-shi─Will a forest regenerate promptly after fire ?─.

Dynamic state of the floor vegetation in a fire-damaged sugi forest in Tottori-shi─Will a forest regenerate promptly after fire ?─.

Radiocesium distribution in sugi (Cryptomeria japonica) in Eastern Japan: translocation from needles to pollen

We assessed the radiocesium contamination of sugi (Cryptomeria japonica) forests in eastern Japan from November 2012 to February 2013, including 80 sites in Fukushima and 35 sites in other regions (Tohoku and Kanto-Koshinetsu), by measuring the 137Cs concentrations in needles of different ages, male flowers, and pollen. Over a wide geographic area, needles that were present at the time of the Fukushima Dai-ichi Nuclear Power Plant accident contained much higher 137Cs concentrations than needles that emerged after the accident. This result, together with visual analysis of 137Cs distribution using autoradiography, indicated that some of the 137Cs derived from direct fallout remained on the surface of the older needles. Since we also detected 137Cs in younger needles and male flowers, we concluded that 137Cs was translocated toward the tips of sugi needles. The 137Cs concentration in male flowers was higher than and positively correlated with that in the currently growing (2012) needles. Also, a positive relationship was observed between the 137Cs concentration of male flowers and pollen, and they were found to be nearly identical 137Cs concentration. These results indicate the occurrence of acropetal translocation of 137Cs from old needles to young needles, male flowers and pollen. However, the results as related to 137Cs concentration in the needles of three different ages differed from the results of similar studies conducted more than 4 y after the Chernobyl accident. This suggests that, 2 y after the Fukushima Dai-ichi NPP accident, the distribution of 137Cs in the sugi forests has not yet reached a steady state.

Actual conditions of the selection cutting system for Sugi forest before World War II in Akita National Forest

Actual conditions of the selection cutting system for Sugi forest before World War II in Akita National Forest

Analysis of Grouped Growth Patterns in Even-Aged Sugi Forest Stand within the Framework of Mixture Model

Analysis of Grouped Growth Patterns in Even-Aged Sugi Forest Stand within the Framework of Mixture Model

複数の成長パターンを持つスギ単純同齢林における炭素固定量予測

複数の成長パターンを持つスギ単純同齢林における炭素固定量予測

Carbon stock estimates for sugi and hinoki forests in Japan

Forest inventory data are widely used for broad-scale quantification of forest carbon budgets. Such data usually represent forest wood volume (m 3 ha −1), which needs to be converted to biomass carbon value (Mg C ha −1) for carbon stock estimates. Our main objective is to estimate the carbon stock for all sugi ( Cryptomeria japonica D. Don) and hinoki ( Chamaecyparis obtusa Endl.) plantations in Japan on the basis of age-class-based forestry statistics. To achieve this purpose, we estimated regional wood volume accumulation and biomass allocation over time for sugi and hinoki forests to calculate and map the carbon stock in all sugi and hinoki plantations in Japan on the basis of forestry statistics. Hinoki forests showed smaller accumulation of volume than sugi forests from ca. 25 years old to maturity; the accumulation of wood volume per hectare at 80 years old was <600 m 3 ha −1 for hinoki and >600 m 3 ha −1 for sugi. Patterns of biomass allocation to forest components varied by forest type; the proportion of branch biomass in 0–20-year-old hinoki forests is 5–10% larger than that of sugi; the proportion of stem biomass in the same age range is 5–10% smaller than that of sugi; the ratio of roots was approximately constant as its average value, 20.4% for sugi and 22.7% for hinoki. The ratios of total biomass to bole biomass (i.e., expansion factor (EF), Mg total biomass Mg −1 bole biomass) decreased with increasing age, and became nearly constant after 30 years old for sugi and hinoki. The mean EFs were the same for the two forest types, with a value of 1.72 Mg Mg −1. Our results suggest that sugi and hinoki plantations in Japan, respectively, store 346.4×10 6 and 139.2×10 6 Mg of carbon, with an area-weighted mean of 76.81 and 58.01 Mg C ha −1. High amounts of carbon stock in both sugi and hinoki are located in the southwestern part of Japan.

Effects of Stand Density on the Productivity of Cryptomeria japonica Male Flowers

We have studied male flower production and relative illumination in clonal sugi (Cryptomeria japonica) forests planted at densities of 1,500/ha, 3,000/ha, and 5,000/ha, to clarify the effects of forest management on male flower production. Both the relative illumination and male flower production decrease as the stand density increases. The lowest position at which male flowers are formed decreases as the density of the stand decreases. High thinning intensity promotes male flower production and light pruning is ineffective to reduce male flower production. Therefore, traditional management methods used in sugi forests (i.e. planting at high density, frequent light thinning, intensive pruning and short rotation) are ideal strategies for limiting male flower production.

Forecast of total pollen counts of sugi (Cryptomeria japonica) from the amount of male flower development and the revised total pollen counts

We have successfully forecast the total pollen counts of sugi (Cryptomeria japonica) since 1996 by the amount of male flower development. The amount of male flower development was observed at 11 forests in the Tanba Mountains and 10 forests in the Chugoku Mountains depending on both in Hyogo Prefecture. The amount of male flower development on each tree was assigned to one of five classes by the number of male flowers per spring. After a large harvest of male flowers, the production of male flowers declined in the following years, especially at high altitudes. It was also followed by a decrease in the number of airborne pollen grains in the later pollen season. According to an analysis of weather conditions, total pollen counts were correlated with the high temperature between July 6 and 20 and the total pollen counts of the previous season. However, the amount of male flower development was the most significant indicator for forecasting total pollen counts. Decrease in total pollen counts due to abnormal weather during the pollen season was correlated with discrepancies in forest flowering time according to observations made in the Rokko Mountains. Increase in total pollen counts was connected by a development of the sugi forest areas. Twenty percent of mature sugi forests from 1992 which showed an annual increase were associated with an increase in total pollen counts. The accuracy of the forecast was improved by revising the total pollen counts for weather conditions during the dispersion stage, a decrease in the production of male flowers at high altitude, and an increase in the production of male flowers connected by a developing forest areas.

Logging operation in the thinning of Sugi forests using Tower Yarder (II) : A correlation between improvement of carriage and skillfulness of operation with the operation-time

Logging operation in the thinning of Sugi forests using Tower Yarder (II) : A correlation between improvement of carriage and skillfulness of operation with the operation-time

Logging Operation in the Thinning of Sugi Forests using a Tower Yarder (I) : An Outline of model

Logging Operation in the Thinning of Sugi Forests using a Tower Yarder (I) : An Outline of model

On the crowned snow damage of Sugi forest in Kumamoto Prefecture which occurred in January 1984

On the crowned snow damage of Sugi forest in Kumamoto Prefecture which occurred in January 1984