We investigated the height and suppression status of planted trees in young sugi (Cryptomeria japonica) plantations that were weeded every year in Yame, Fukuoka, Japan, to develop a criterion to determine the need for weeding. Plantations with varying competing vegetation types were studied, and the height of competing vegetation that had recovered one year after weeding differed with variation in the dominate species. Miscanthus (Miscanthus sinensis) exhibited high recovery values, while the recovery heights of three major component species of the competing vegetation (M. sinensis, Rhus chinensis and Mallotus japonicus) were almost the same within each species irrespective of the number of times of weeding (i.e., years after planting). The planted sugi trees tended to be released from suppression according to their height. However, the degree of the release was different for the different vegetation types; generalized linear models demonstrated that sugi needed to be taller in the miscanthus-dominated type than other vegetation types to achieve the same degree of release from suppression. These results suggest that there is no depression of the recovery height for major weeds or trees caused by repeat weeding, and that the weeding criterion should vary with vegetation types, according to their respective post weeding recovery potential. With the assumption that weeding is needed when 90％ of planted sugi tree are taller than surrounding competing vegetation, the critical height of sugi trees is 2.2 m for the miscanthus-dominated type and 1.4 m for the other vegetation types.
The development of tourist industry has affected the livelihoods of local peoples' living around the scenic zones in China. However, only a limited studies exist concrete and detailed information on the impact of the development of tourist scenic spots on local people. This study aims to clarify the impact of scenic zone development to the livelihoods of local people in the surrounding area of scenic zones and it differentiation among local people. The study collected data by conducting interview survey to the scenic zone officers, household survey and practical observation in the Zhi Gong Village adjacent to Jian Men Guan scenic zone, Sichuan Province, China. The results of the study found out that the farmlands of some local people were expropriated for the development of the scenic zone; however, they reduced their reliance on agriculture and migrant work by having/taking the opportunity to enter the tourism business with their land compensation and preferential policies. In contrast, non-expropriated local people could not receive the benefit from tourism. And their main livelihood still has continued dependent on migrant work income, and the second livelihood has become less dependent on agriculture, but increased wage labor. The study concluded that the impact of the development of the scenic zone and local people livelihood have huge gap due to the differences between the location of farmland expropriation and the applied compensation policies of the Provinces.
The environment for the growth of seedlings and small- and medium-sized trees of Yanase-sugi was studied to understand necessary conditions for the natural regeneration of Yanase-sugi trees in Senbonyama Gene Preservation Forest in Kochi, Japan. We measured the height, basal diameter, canopy openness, soil water content of each seedling (less than 1 cm in diameter at breast height) and litter depth around it. We also measured the height, diameter at breast height, canopy openness, relative growth rate of the last 5 years, and soil water content of each small- or medium-sized tree (1 to 40 cm in diameter at breast height), and the total basal area of each of the neighboring trees surrounding it. Yanase-sugi seedlings were observed only on fallen trees and 98.6％ of the seedlings were growing under the relatively dark conditions of approximately less than 12％ canopy openness. On the other hand, 89.3％ of the small- and medium-sized trees grew under the conditions of more than 12％ canopy openness. The small- and medium-sized trees showed the significant relationship of the relative growth rate to canopy openness, and not to any other environmental factors. Therefore, the natural regeneration of Yanase-sugi in Senbonyama Gene Preservation Forest may need the light conditions of at least 12％ canopy openness. As a result, seedling growth can not be expected in the current situation of this forest unless drastic improvements in light conditions are made.
The objective of this research is to clarify the present situation of management and stand structure of Moso bamboo forests in China by questionnaire survey with 56 management entities and stand structure investigation in managed bamboo forests in Yixing City, Jiangsu. Our results revealed the existence of extensive management for the purpose of harvesting both bamboo culms and shoots, and the differences of management operations and stand structure of bamboo forests between management entities. The stand structure of managed bamboo forests were revealed: 4,348 culm/ha as mean density, 9.6cm as culm diameter, 30.38m2/ha as stand basal area, and the culm stand was close to regular distribution. Moreover, the relationship between the stand indices showed some trends: as spatial density increase, the mean DBH and percentage of new culm continuously decreases inversely and the culm stand gets closer to random or clustered distribution. In addition to the aging of the management entities, and rising of labor cost may cause the negligent of management particularly in the bamboo grove that are remote from the woodland path. When we formulate sustainable bamboo forest resource management and utilization,it is considered to be necessary to understand the different characteristics among bamboo forest management entities, and the relationship between management and stand structure.
To obtain the precise geographic coordinates and genetic line information of seedlings planted in the genetic test site for tree breeding, we developed a simple mapping method using an RKT-GNSS kit, C94-M8P application board, and individual seedling labels with a QR code. In the two test sites, we estimated the geographic coordinates of ca. 90 seedlings three times using a C94-M8P GNSS kit with post-processing kinematics analysis and real-time kinematic GNSS. The average standard deviations of replications were 2.6-6.0 cm for horizontal coordinates and 3.6-12.5 cm for vertical coordinates, indicating a high precision of measurements. To evaluate the accuracy of the method, we compared the geographic coordinates estimated using the C94-M8P and geographic coordinates measured as a true value using a dual-frequency GNSS receiver and a Total Station at one test site. The differences of the coordinates were 6.4 cm and 11.3 cm in horizontal and vertical coordinates, respectively. This suggests that the geographic coordinates estimated by the C94-M8P are very accurate. When we obtained individual identification codes of 90 seedlings from their QR code label using QR code reader and simultaneously obtained the geographical coordinates using the C94-M8P, the time required to obtain a measurement was 13-21 seconds per seedling. These results suggest that the new method is efficient and can be applied to real operations in forest tree breeding.
In this study, the authors focused on biodegradable nonwoven fabric pot and reveal the growth characteristics of Japanese cedar and hinoki cypress saplings with biodegradable nonwoven fabric pot, and evaluated their growth characteristics and the decomposability of the pot during 2 years after planting. As a result, there was little difference in the diameter growth of both tree species and there was a difference in tree height growth and underground weight in the first growing period. In the second growing period, there was no difference in relative growth rate between the saplings with pot and the control saplings for the cedar saplings, while there was a difference in underground weight. The relative growth rate and underground weight of the cypress saplings with pot were decreased. As a result of evaluating the decomposability of the pot, it was confirmed that the tensile strength was reduced by a maximum of 27％ two years after planting. We concluded that the pot was not completely decomposed in 2 years after planting, and cypress saplings showed a decrease in growth due to the pot.
In order to strengthen the system for increasing the production of male sterile cedar seedlings, we worked with people involved in paddy rice agriculture to hydroponically cultivate container seedlings using fallow fields. After constructing a nursery pool with a depth of about 5 cm in a fallow rice paddy with running irrigation water, we grew two-year-old container seedlings in the pool from May to October. We found the survival rate to be high, at about 98％, and the amount of growth was more than of seedlings grown using conventional greenhouse cultivation. We performed such seedling raising tests using fallow rice fields in both coastal and mountains area and found that plants grew well in both situations, leading us to believe that this cultivation method could be used in a wide range of areas where there are paddy fields. The survival rate and growth rate of seedlings cultivated hydroponically were no different from those of seedlings cultivated in conventional greenhouses when planted to the reforestation area. Based on these facts, we believe this cultivation technique, which consists simply of immersing container seedlings in flooded fallow rice fields, to be a labor-saving and low-cost method of raising seedlings because it does not require the use of a greenhouse or an automatic watering device.