• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.15 no.6
• /
• pp.61-67
• /
• 2012

This study was conducted to evaluate the effects of soil covering and vegetation base materials implementation on the growth of Lespedeza cyrtobotrya Miq. in abandoned coal mine land. We compared the biomass of L. cyrtobotrya at the study plots of four different soil covering depth (control, 10cm, 20cm, and 30cm) and four different compounds of vegetation base materials composed of soil conditioner (S), erosion control (E), and peat moss (P) (control, S+P, E+P, and S+E+P). The result showed that the biomass of L. cyrtobotrya was higher in the study plots implemented with soil covering than control plot, although the increase in biomass was not constant with soil covering depth. In case of the vegetation base materials treatments, the biomass was highest in S+E+P plot, and S+P and E+P plots showed higher biomass than control plot.

• Journal of the Korean Wood Science and Technology
• /
• v.43 no.5
• /
• pp.682-690
• /
• 2015

The bonding performance of two types of wood adhesives, namely phenol-resorcinol-formaldehyde (PRF) resin and melamine-urea-formaldehyde (MUF) resin for glued laminated timber manufactured by high frequency (HF) heating was evaluated. The HF heating system consists of HF oscillator with dielectric heating system for curing adhesives, and hydraulic press system for clamping glued laminated timber. The designed frequency and output power of the HF system was as 5 MHz and 60 kW, respectively. To verify dielectric heating mechanism under HF oscillation, the heat loss factors of laminae and adhesives were measured. The results show that it is possible to selectively heat adhesives for their curing due to the remarkably higher loss factor of the adhesives than those of wood laminae. The temperature of adhesive in the bonding line reached up to the set temperature within a few seconds by high frequency oscillating, which advanced the curing of adhesive afterwards. The bonding performance, such as shear strength of bonding line, water soaking delamination, and boiling water soaking delamination of PRF resin met the requirement of Korean Standard (KS), however the MUF resin did not meet the KS requirement of boiling water soaking delamination. These results indicate that the HF heating system is successful to manufacture glued laminated timbers with PRF resins to meet the bonding requirements.

• Journal of Korean Society of Forest Science
• /
• v.96 no.3
• /
• pp.369-375
• /
• 2007

We examined two Populus species (Populus euramericana and Populus alba ${\times}$ Populus glandulosa) trees grown under livestock waste leachate treatment in the field. We investigated their physiological properties (photosynthetic rate, chlorophyll contents, transpiration rate and intercellular $CO_2$ concentration) and antioxidant enzyme activities. Ascorbate peroxidase and glutathione reductase were analyzed. According to our measurements, P. euramericana at control site showed a lower total chlorophyll contents, photosynthetic rate, intercellular $CO_2$ concentration, transpiration and stomatal conductance than those of trees at treatment site. P. alba ${\times}$ P. glandulosa showed low stomatal conductance and low photosynthetic rate.

• Journal of Korean Society of Forest Science
• /
• v.95 no.3
• /
• pp.274-281
• /
• 2006

In this study, I aimed to suggest political data on the plantation of chestnut trees given the local features by conducting an analysis on the economic efficiency of the plantation of chestnut trees aimed at chestnut tree plantation farmhouses (total 67 farmhouses) in Chungbuk, Chungnam, Jeonbuk, Jeonnam and Gyeongnam, which are the chief producing place in Korea. As a result, the central area (Chungbuk, Chungnam) was proven to post 2.7 times as many as the average total income, 3.9 times as many as income, and 12.1 times as many as net income per ha when compared with those in the southern area (Jeonnam, Gyeongnam). That is, the southern area demonstrated a very low economic efficiency on the plantation of chestnut trees compared with that of the central area, and this was caused by the reduction of chestnut production and the degradation of chestnut quality due to the aging of chestnut trees. Therefore, it is imperative to consistently renovate aged chestnut orchards and manage them in the southern area.

• Current Research on Agriculture and Life Sciences
• /
• v.2
• /
• pp.42-55
• /
• 1984

The direction of scientific researches on tree improvement and forest management in several universities and research institutes in Japan can be summarized as follows: They put a great emphasis on sugi, Cryptomeria japonica and cypress, Chamaecyparus oblusa which are two major conifer species largerly planted in the Japanese forestry. In the research of sugi, a great concern has been made in evaluating inheritance of forest tree, quantitative characters and genetic parameter of growth, and in breeding for resistance to diseases and insects and to all the natural calamities. Interaction between environmental conditions and genetic nature of tree can be concerned factors in relation with forest damage, together with silvicultural conditions and pest infestation. Selfing hybrids of $F_1$ made from crossing twisted-leaf sugi, defomity leaf type and midori sugi, normal leaf type segregated the normal needle, twisted needle, green leaf and albino leaf type. It seemed that separation of many defomity individuals can be governed by two dominant complementary genes and from the near loci of which it was detected lethal genes. 52% of Japanese forestry is occupied by the small forest landowners like Korean forestry. This made difficulty for forest improvement such as progressive afforestation and for capital accumulation form forestry. The Forest Corporation was established at first in 1959 to aming at productive forestry structure and forest management, and afforestation. For these purpose, 35 Forest Corporations are at moment operating throughout Japan. However, investment in forestry business becomes less attractive since the wage in forest production duction increased in higher trend. than timber price. Therefore, an artifical afforestation becomes yearly decreased. At present. the self-sufficient rate of timber production in Japan is about 35%, and so a great effort is being made to increase self-sufficient rate of timber production.

• Korean Journal of Breeding Science
• /
• v.41 no.4
• /
• pp.377-384
• /
• 2009

Three-year-old seedlings of susceptible Pinus densiflora and resistant Pinus x rigitaeda were each inoculated with the pinewood nematode, Bursaphelenchus xylophilus, to compare disease development. Needle dehydration was evident on seedlings of P. densiflora by 20 days after inoculation, 10 days earlier than this symptom was observed on P. ${\times}$ rigitaeda. Xylem drying was more frequent in seedlings of P. densiflora than in that of P. ${\times}$ rigitaeda between 20 and 60 days after inoculation. No significant differences were found between P. densiflora and P. ${\times}$ rigitaeda for stem water content or for stem and leaf relative water content in current-year branches after nematode inoculation, but the average number of B. xylophilus recovered from stems differed significantly between the two groups. The number of B. xylophilus recovered from stems was negatively correlated with the stem water content and with stem and leaf relative water content. By the time the experiment was terminated at 60 days after inoculation, all 3 of the last group of P. densiflora seedlings had died, but 2 of the 3 remaining P. ${\times}$ rigitaeda hybrid seedlings were still alive. Additional studies are needed to further explore the specific mechanisms preventing nematode multiplication in the seedlings of resistant P. ${\times}$ rigitaeda.

• Korean Journal of Plant Taxonomy
• /
• v.51 no.4
• /
• pp.372-377
• /
• 2021

We report a previously unrecorded woody species, Stachyurus praecox Siebold & Zucc. (Stachyuraceae), in Korea. This species is considered to be endemic to Japan. Stachyurus praecox was collected for the first time in an evergreen forest on an uninhabited island of Bongsun-ri, Saengil-myeon, Wando-gun, Jeollanam-do in Korea. The inflorescence of the species was racemose and pendulous on the axils of the previous year's branches. Flowers bloomed from March to April. They were functionally dioecy but morphologically hermaphrodite. This woody species was named 'Wan-do-sul-kkot-na-mu' in Korean based on the shape of its inflorescence. Morphological characteristics and illustrations of this woody species have been provided with a distribution map and photographs of the natural habitat.

• Journal of Korean Society of Forest Science
• /
• v.113 no.2
• /
• pp.164-169
• /
• 2024

In South Korea, most felling operations involve the use of chainsaws due to steep and rough terrains. This felling technique is responsible for approximately 80% of all fatalities mainly due to unpredictable felling directions. Therefore, readjust monitorised felling is imperative to improve safety in different working conditions. This study examined the effect of wedging on felling direction error and productivity during felling operations. When wedging was applied, a felling direction error within 22° and a productivity of 0.63 m³/min were obtained. These results show a decrease in mean directional error and a dimish in productivity. Thus, although wedging reduces productivity, it is a necessary strategy to improve safety.

• Weed & Turfgrass Science
• /
• v.4 no.3
• /
• pp.262-267
• /
• 2015

In order to establish the efficient sod production and soil management, there is a need to perform research on the growing condition of zoysiagrass on soil environments. With an attempt to identify the growth of zoysiagrass and the chemical characteristics of soil according to different growing seasons, this study was carried out in separate areas where zoysiagrass has been grown for 1 year, 10 years, 20 years, and 30 years. As the growing season became longer, bulk density of the soil was increased, porosity and gaseous phase were decreased. The level of pH was highest in the area where zoysiagrass has been produced for 30 years, whereas total nitrogen and organic matters were found to be the greatest in where zoysiagrass has been produced for 1 year. Accordingly, the chemical properties of soil were deteriorated more in the area with continuous cropping than in the area with 1 year of cropping. As the time period of producing zoysiagrass became longer, growth of shoot and root were decreased. In this study, it is required to produce zoysiagrass through soil improvement in areas that have been used for production for over 10 years.

• Korean Journal of Plant Resources
• /
• v.19 no.5
• /
• pp.640-648
• /
• 2006

The distribution and status of naturalized plants in Jeju Island were investigated in this study. As results, the naturalized plants in Jeju Island were total of 254 taxa including 47 families, 161 genera, 248 species and 6 varieties. By the growth habits, annuals held the most percentage including 107 taxa (42.13%). Seventy nine taxa (31.1%) were appeared to have erect type in growth forms and 203 taxa (79.9%) are non-clonal growth form in disseminule forms by radicoid. The most of dormancy form in life form were therophytes as 150 taxa (59%), and following as 53 taxa (20.9%) for hemicryptophytes, and 26 taxa(10.2%) for geophytes. Among the naturalized plants, 115 taxa (36.7%) were originated from Europe, 69 taxa (22%) from Asia and 59 taxa (18.8%) from North America. Twenty eight percent of them were introduced as feeds or mixed seeds of imported cereals.