• Title/Summary/Keyword: Stand density

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Photosynthesis of ×Populus albaglandulosa in Relation to Leaf Age (×Populus albaglandulosa의 엽령별(葉齡別) 광합성(光合成))

  • Kim, Chung Suk;Lee, Suk Koo;Sun, Soon Wha
    • Journal of Korean Society of Forest Science
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    • v.34 no.1
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    • pp.63-71
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    • 1977
  • ${\times}$Populus albaglandulosa has been needed optimum stand density according to various site and its wood usage. It is assumed that optimum stand density can be estimated by investigating of response of ${\times}$P. albaglandulosa to the light factor of stand. For that reason, the photosynthesis of ${\times}$Populus albaglandulosa grown under the controlled planting density was studied in relation to its leaf age by the aid of the Infrared gas analyzer. Rate of net photosynthesis was smaller in matured leaves than young leaves below $8^{\circ}C$, while, it was larger than young leaves above $8^{\circ}C$. Temperature for the maximum net photosynthesis of young leaves and old leaves was about $30^{\circ}C$ and $25^{\circ}C$ respectively. Saturated light intensity varied slightly as leaf age from 28 Klux to 35 Klux, but net photosynthesis rate in the range of light intensity showed deep differences. Old leaves marked the lowest rate, $1.6\;CO_2\;mg/dm^2/hr$, young leaves marked the medium rate, 1.7 to $2.2\;CO_2\;mg/dm^2/hr$, and matured leaves marked the most efficient photosynthesis, 2.9 to $3.5\;CO_2\;mg/dm^2/hr$. Young leaves of 5 days old had the highest light compensation point, while matured leaves of 35 days-old had the lowest point. Rates of dark respiration in both young leaves and old leaves were higher than that of matured leaves. Trees which were planted at space $80cm{\times}80cm$ showed productive assimilation function over the one-third of height where relative light intensity is 35%.

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Biomass Production of Machilus thunbergii S. et Z. Stand at Bogil Island in Korea (후박나무림(林)의 물질생산량(物質生産量)에 관(關)하여)

  • Lee, Jyung Seok;Kim, Choon Sig
    • Journal of Korean Society of Forest Science
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    • v.77 no.1
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    • pp.10-16
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    • 1988
  • This study was carried out to estimate the aboveground-biomass of Machilus thunbergii, warm-temperature evergreen broad leaved tree, growing in the seashore near Bogil island located at the southern part of the Korean peninsula. The bark of M. thunbergii was used for medicine in the Korea. The results were summarized as follows : 1) The aboveground-biomass was 123.708 tons/ha and the biomass of branch bark greater than 3cm in branch diameter was 1/5 of total bark mass(8.095 tons/ha). Dry matter density was $1.77ha/m^3$ and leaf area index 8.08. 2) Net production of the stand was estimated as 16.051 tons/ha/yr and the leaf was the greatest, followed by stemwood, branchwood, stem-bark and branch-bark. 3) The net assimilation rate of the stand was 1.384 kg/kg/yr. The efficiency of leaves to produce stem was 0.451 kg/kg/yr and that of bark 0.051 kg/kg/yr. Biomass accumulation ratio was 7.707 kg/kg/yr.

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Whole Stand Survival Prediction Model in Slash Pine Plantations Infected with Fusiform Rust (수병(銹病)에 감염(感染)된 슬래쉬소나무 조림지(造林地)에 대한 임분단위(林分單位)의 생존 (生存) 예측모형(豫測模型))

  • Lee, Young-Jin;Hong, Sung-Cheon
    • Journal of Korean Society of Forest Science
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    • v.89 no.4
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    • pp.480-487
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    • 2000
  • Repeated measurement of 472 permanent subplots in slash pine (Pinus elliottii Engelm.) plantations were used to develop survival prediction equations for predicting future number of planted slash pine trees. On the average, about 40 percent of the slash pines in the experimental sites had a stem cankers due to fusiform rust (Cronartium quercuum [Berk.] Miyabe ex Shirai f. sp. fusiforme) incidence. A stand level survival prediction model was developed that incorporated the incidence of fusiform rust and allowed the transition paths of trees from an uninfected stage to an infected stage. Predicted total surviving number of trees is obtained by adding together the predicted number of infected and uninfected trees. The influence of natural hardwood density and site quality on slash pine survivals tended to show a negative effects on future survivals.

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A Study on the Bamboo Shoot's Damage of Phyllostachys edulis Riv. by Field-mice -Especially on the Inhabitation Environment and Damaged Types of Field-mice- (야서(野鼠)의 맹종죽순(孟宗竹筍) 피해(被害)에 관(關)한 연구(硏究) -야서(野鼠)의 서식환경(棲息環境) 피해형태(被害形態)를 중심(中心)으로-)

  • Park, Kwang Woo
    • Journal of Korean Society of Forest Science
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    • v.70 no.1
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    • pp.55-62
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    • 1985
  • This study was made on bamboo shoot's damage of Phyllostachys edulis by field mice in Jinju, Gyeongsangnam-do, and grasped the inhabitation environment by the analysis of around and lower vegetation in damaged bamboo stands, and made clear the species of field mice in damaged bamboo stand, the damaged degree and rate, therefore, were put in practice for contribution with damage prevention and extermination. The results were summarized as follows; The damaged degree were influenced by inhabitation environment and stand density around damaged bamboo stands. The damaged degree were shown 4,359.1 g with 7.1 shoots per. ha and the rate 0.23%. The damage season were from the middle of April to the middle and end of May, the most damaged season was about April 23. The length of damaged bamboo shoot was mean 28.12 cm, the inside diameter 7.49 cm, the weight 613.96 g. The damaged type of parts was shown to more numerous overland and surface damaged type of three types; overland, surface and underground damaged type. The field mice to be captured in damaged bamboo stand were three species; Apodemus agrarius coreae, Mus molossinus and Crocidura lasiura, the species of main damage was Apodemus agrarius coreae of captured Rodentia's 2 species. Crocidura lasiura in order Insectivora was found to inhabitate for the first time at southern region in Korea.

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Effects of Hardwood Interspecific Competition on Stand Level Survival Prediction Model in Unthinned Loblolly Pine Plantations (테에다소나무 조림지(造林地)에서 활엽수(闊葉樹)와의 종간경쟁(種間競爭)이 임분수준(林分水準) 생존(生存) 예측모형(豫測模型)에 미치는 영향(影響))

  • Lee, Young-Jin;Hong, Sung-Cheon
    • Journal of Korean Society of Forest Science
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    • v.89 no.1
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    • pp.49-54
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    • 2000
  • Stand level survival prediction model was developed that incorporated the incidence of fusiform rust(Cronartium quercuum [Berk.] Miyabe ex Shirai f. sp. fusiforme) and allowed the transition of trees from an uninfected stage to an infected stage. The influence of hardwood interspecific competition on the survival of unthinned planted stands of loblolly pine (Pinus taeda L.) was analyzed by using of information from twelve years of tracking a set of permanent plots representing a broad range of plantation parameters. Significant interaction effects between site index and hardwood basal area per acre were revealed in the survival model. Survival of the planted pines decreased with increasing density of hardwood trees per acre and site index as the productivity rating of the forest land. The effects of hardwood trees interspecific competition on loblolly pine tended to show a negative effect on predicted future number of planted pine trees.

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Forest Stand Structure, Site Characteristics and Carbon Budget of the Kwangneung Natural Forest in Korea (광릉 활엽수천연림의 산림식생구조, 입지환경 및 탄소저장량)

  • Jong-Hwan Lim;Joon Hwan Shin;Guang Ze Jin;Jung Hwa Chun;Jeong Soo Oh
    • Korean Journal of Agricultural and Forest Meteorology
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    • v.5 no.2
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    • pp.101-109
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    • 2003
  • The study area, Kwangneung Experiment Forest (KEF) is located on the west-central portion of Korean peninsula and belongs to a cool-temperate broadleaved forest Bone. At the old-growth deciduous forest near Soribong-peak (533.1 m) in KEF, we have established a 1 ha permanent plot ($100m{\times}100m$) and a flux tower, and the site was registered as a KLTER(Korean long-term ecological research network) and DK site of KoFlux. In this site, we made a stemmap of trees and analyzed forest stand structure and physical and chemical soil characteristics, and estimated carbon budgets by forest components (tree biomass, soils, litter and so on). Dominant tree species were Quercus serrata and Carpinus laxiflora, and accompanied by Q. aliena, Carpinus cordata, and so on. As a result of a field survey of the plot, density of the trees larger than 2 cm in DBH was 1,473 trees per ha, total biomass 261.2 tons/ha, and basal area $28.0m^2$/ha. Parent rock type is granite gneiss. Soil type is brown forest soil (alfisols in USDA system), and the depth is from 38 to 66 cm. Soil texture is loam or sandy loam, and its pH was f개m 4.2 to 5.0 in the surface layer, and from 4.8 to 5.2 in the subsurface layer. Seasonal changes in LAI were measured by hemispherical photography at the 1.2 m height, and the maximum was 3.65. And the spatial distributions of volumetric soil moisture contents and LAIs of the plot were measured. The carbon pool in living tree biomass including below ground biomass was 136 tons C/ha, and 5.6 tons C/ha is stored in the litter layer, and about 92.0 tons C/ha in the soil to the 30 cm in depth. Totally more than about 233.6 tons C/ha was stored in DK site. These ground survey and monitoring data will give some important parameters and validation data for the forest dynamics models or biogeochemical dynamics models to predict or interpolate spatially the changes in forest ecosystem structure and function.

Development of Prediction Model of Fuel Moisture Changes After Precipitation in the Spring for the Pine Forest Located the Yeongdong Region (Focused on the Down Wood Material Diameter) (영동지역 봄철 소나무림에서 강우후 연료습도변화 예측모델 개발 (지표연료 직경두께를 중심으로))

  • Lee, Si-Young;Kwon, Chun-Geun;Lee, Myung-Woog;Lee, Hae-Pyeong
    • Fire Science and Engineering
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    • v.24 no.4
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    • pp.18-26
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    • 2010
  • The change of fuel moisture according to the passed days after a raindrop is very important to forecast risk of forest fire and to make a good use of forest fire watchmen. For that reason, in the Spring of 2007, we researched pine forest that were widespread growing in Yeongdong region to find out the condition of forest fire risk. We developed the forecast model of fuel moisture change on dead tree branches which were dropped on the ground and less than 0.6 cm, 0.6~3.0 cm, 3.0~6.0 cm, and more than 6.0 cm in diameter after more than 5.0 mm in precipitation. The result showed that the less diameter of ground fuel and small stand of pines the faster diminishing of fuel moisture, and the days of reaching to a forest fire danger fuel moisture level were represented by two (2) days for less than 0.6 cm diameter of small stand of pine and three (3) days for 0.6~3.0 cm diameter one, respectively. By those results, we developed the forecast model($R^2=0.76{\sim}0.92$) of fuel moisture change on different diameter of small stand of pine, and found that the model had statistical significant of 1% level after we applied it to the data of 2008 after the same period of raindrop by actual meteorological measurement.

Analysis of Optimal Thinning Prescriptions for a Cryptomeria japonica Stand Using Dynamic Programming (동적계획법 적용에 의한 삼나무 임분의 간벌시업체계 분석)

  • Han, Hee;Kwon, Kibeom;Chung, Hyejean;Seol, Ara;Chung, Joosang
    • Journal of Korean Society of Forest Science
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    • v.104 no.4
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    • pp.649-656
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    • 2015
  • The objective of this study was to analyze the optimal thinning regimes for timber or carbon managements in Cryptomeria japonica stands of Hannam Experimental Forest, Korea Forest Research Institute. In solving the problem, PATH algorithm, developed by Paderes and Brodie, was used as the decision-making tool and the individual-tree/distance-free stand growth simulator for the species, developed by Kwon et al., was used to predict the stand growth associated with density control by thinning regimes and mortality. The results of this study indicate that the timber management for maximum net present value (NPV) needs less number of but higher intensity thinnings than the carbon management for maximum carbon absorption does. In case of carbon management, the amount of carbon absorption is bigger than that of timber management by about 6% but NPV is reduced by about 3.2%. On the other hand, intensive forest managements with thinning regimes promotes net income and carbon absorption by about 60% compared with those of the do-nothing option.

Canopy Structure and Light Interception as Related to Forage Growth and Dry Matter Production in Pure and Mixture Stands. (목초 단, 혼파군락에서의 초형구조와 광이용성 및 건물수량생산성)

  • 이호진;윤진일;이광회;임근발
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.28 no.2
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    • pp.272-279
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    • 1983
  • Canopy structure and light interception were investigated as related to forage growth and dry matter production in four swards; pure orchardgrass, pure ladino clover, orchard-ladino mixture, and multi-mixture that was consisted of four grasses and three legumes. In spring, multi-mixture stand had the highest LAI, while ladino clover pure stand had low LAI but the highest leaf volume density(L$_{v}$ ). In fall, both pure orchardgrass and orchard-ladino mixture had higher LAI and L$_{v}$ than others. Orchard pure stand was an electophile canopy with K, light extinction coefficient, of 0.29-0.43, pure ladino clover a planophile canopy with K of 0.72, and both mixtures a plagiophile canopy with K of 0.43-0.58. Dry matter yields had highly significant correlation with LAI in all stands. Optimum LAI for pure orchardgrass was estimated above 6.0 and for pure ladino clover, orchard-ladino mixture and multi-mixture were about 3.8,5.0 and 8.0, respectively. Conclusion was made that multi-mixture and orchard-ladino mixture had better canopy structure to improve light penetration and forage yield than pure stands.

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The Effect of Hounsfield Unit Value with Conventional Computed Tomography and Intraoperative Distraction on Postoperative Intervertebral Height Reduction in Patients Following Stand-Alone Anterior Cervical Discectomy and Fusion

  • Lee, Jun Seok;Son, Dong Wuk;Lee, Su Hun;Ki, Sung Soon;Lee, Sang Weon;Song, Geun Sung;Woo, Joon Bum;Kim, Young Ha
    • Journal of Korean Neurosurgical Society
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    • v.65 no.1
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    • pp.96-106
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    • 2022
  • Objective : The most common complication of anterior cervical discectomy and fusion (ACDF) is cage subsidence and maintenance of disc height affects postoperative clinical outcomes. We considered cage subsidence as an inappropriate indicator for evaluating preservation of disc height. Thus, this study aimed to consider patients with complications such as reduced total disc height compared to that before surgery and evaluate the relevance of several factors before ACDF. Methods : We retrospectively reviewed the medical records of 40 patients who underwent stand-alone single-level ACDF using a polyetheretherketone (PEEK) cage at our institution between January 2012 and December 2018. Our study population comprised 19 male and 21 female patients aged 24-70 years. The minimum follow-up period was 1 year. Twenty-seven patients had preoperative bone mineral density (BMD) data on dual-energy X-ray absorptiometry. Clinical parameters included sex, age, body mass index, smoking history, and prior medical history. Radiologic parameters included the C2-7 cobb angle, segmental angle, sagittal vertical axis, disc height, and total intervertebral height (TIH) at the preoperative and postoperative periods. Cage decrement was defined as the reduction in TIH at the 6-month follow-up compared to preoperative TIH. To evaluate the bone quality, Hounsfield unit (HU) value was calculated in the axial and sagittal images of conventional computed tomography. Results : Lumbar BMD values and cervical HU values were significantly correlated (r=0.733, p<0.001). We divided the patients into two groups based on cage decrement, and 47.5% of the total patients were regarded as cage decrement. There were statistically significant differences in the parameters of measuring the HU value of the vertebra and intraoperative distraction between the two groups. Using these identified factors, we performed a receiver operating characteristic (ROC) curve analysis. Based on the ROC curve, the cut-off point was 530 at the HU value of the upper cortical and cancellous vertebrae (p=0.014; area under the curve [AUC], 0.727; sensitivity, 94.7%; specificity, 42.9%) and 22.41 at intraoperative distraction (p=0.017; AUC, 0.722; sensitivity, 85.7%; specificity, 57.9%). Using this value, we converted these parameters into a bifurcated variable and assessed the multinomial regression analysis to evaluate the risk factors for cage decrement in ACDF. Intraoperative distraction and HU value of the upper vertebral body were independent factors of postoperative subsidence. Conclusion : Insufficient intraoperative distraction and low HU value showed a strong relationship with postoperative intervertebral height reduction following single stand-alone PEEK cage ACDF.