• Journal of Korean Society of Forest Science
• /
• v.21 no.1
• /
• pp.39-45
• /
• 1974

The objects of this study are to induce the experimental equation suitable to estimate the height growing process, and to get some information that could be to reduce the error percent on determining the site index. The height growing process per sample plot were made up from the height age curve getted through the stem-analysis of the dominant tree. The 11 equations were calculated in the functional formulas between the age and the dominant height of Alnus hirsuta, Larix leptolepsis, L. Gmelini, P. koraiensis, Abies holophylla, P. rigida, Q. acutissima and Q. aliena. The suitable equation for estimating the guide curve were selected with the highest correlation and the low standard error with comparision on the age-height distributed map as Fig. 2. The suitable equation is different between the species as their calculated results as follows; The growing process of tree height are occasionally found to be polymorphous in the growth pattern as Fig. 3. By this result, the site index are practically found to be always not constant but shows variation to age in same plot as example 5. So, that the site index are estimated from the height-growth curve to age drawing by the stem-analysis or the polymorphic-curve, are concluded to be suitable on the study of site evaluation.

• Journal of Korea Foresty Energy
• /
• v.25 no.1
• /
• pp.31-38
• /
• 2006

Quercus mongolica is the most common hardwood species distributed in Korea. This study was conducted to investigate the biomass and energy content of the belowground biomass of Q. mongolica and to obtain the regression equation for estimating root biomass using the tree height and diameter at breast height (DBH). A total of 18 sample trees ranging 20 to 60 year-old were selected in the study sites. Tree height, DBH, age, and weight of stemwood, sapwood, heartwood, stembark, branch, leaf, and root were measured for total biomass. The highly positive correlation was shown between the biomass of most of variables of aboveground components and root biomass. The regression equation of the aboveground total biomass was $log\;W_A\;=\;1.469\;+\;0.992\;log\;D^2H\;(R^2 =0.99)$. The regression equation of the belowground biomass was $log\;W_R\;=\;1.527\;+\;0.808\;log\;D^2H\;(R^2\;=\;0.97)$. The mean energy contents of sapwood, heartwood, bark, leaf, and root were 19,594 J/g DW, 19,571 J/g DW, 19,999 J/g DW, 20,664 J/g DW, and 19,273 J/g DW, respectively. The results obtained from this study can be used to estimate biomass and energy content of belowground using easily measurable variables such as DBH and tree height ranging from 20 to 60-year-old Q. mongolica stands.

• Journal of Korean Society of Forest Science
• /
• v.98 no.2
• /
• pp.178-182
• /
• 2009

A new mixed-effects model was developed that predicts individual-tree total height for Pinus densiflora trees in Gangwon province as a function of individual-tree diameter (cm). The mixed-effects model contains two random-effects parameters. Maximum likelihood estimation was used to fit the model to 560 height-diameter observations of individual trees measured throughout Gwangwon province in 2007 as part of the National Forest Inventory Program in Korea. The new model is an improvement over fixed-effects models because it can be calibrated to a local area, such as an inventory plot or individual stand. The new model also appears to be an improvement over the Forest Resources Evaluation and Prediction Program for the ten calibration trees used in this study. An example is provided that describes how to estimate the random-effects parameters using ten calibration trees.

• Safety and Health at Work
• /
• v.6 no.4
• /
• pp.279-288
• /
• 2015

Background: In this study, the measurement of job stress of electric overhead traveling crane operators and quantification of the effects of operator and workplace characteristics on job stress were assessed. Methods: Job stress was measured on five subscales: employee empowerment, role overload, role ambiguity, rule violation, and job hazard. The characteristics of the operators that were studied were age, experience, body weight, and body height. The workplace characteristics considered were hours of exposure, cabin type, cabin feature, and crane height. The proposed methodology included administration of a questionnaire survey to 76 electric overhead traveling crane operators followed by analysis using analysis of variance and a classification and regression tree. Results: The key findings were: (1) the five subscales can be used to measure job stress; (2) employee empowerment was the most significant factor followed by the role overload; (3) workplace characteristics contributed more towards job stress than operator's characteristics; and (4) of the workplace characteristics, crane height was the major contributor. Conclusion: The issues related to crane height and cabin feature can be fixed by providing engineering or foolproof solutions than relying on interventions related to the demographic factors.

• Journal of Korean Society of Forest Science
• /
• v.110 no.4
• /
• pp.678-688
• /
• 2021

This study was conducted to provide growth characteristics and stand information in preparation for natural regeneration method and silvicultural treatment of seed tree method in Korean red pine stands by using the field inventoried data 18 years after the seed tree regeneration method in 2001 and analyzing the stand and sapling characteristics. The study area was located in the Research Forest of Kangwon National University, Chuncheon-si, Gangwon-do. In November 2018, we collected tree measurement factors, such as diameter at breast height (DBH), height, crown class, stem quality, tree age, and annual height increment on the established plots. We calculated the basal area, volume, height-diameter ratio (HD ratio), and additional stand density variables such as the relative density and %stocking to analyze the managed stands. The number of mother trees was 58 trees/ha, with a 17.7% stocking level, whereas the number of saplings was 2,330 trees/ha, with a 79.0% stocking level. In germination, the age distribution of saplings ranged from 2001 to 2007, with most belonging to 15-16 years. The development condition of saplings was 10 cm in DBH and 8 m in height. DBH and height were higher as the crown class is more dominant, and this difference was statistically significant in the analysis of variance and Duncan's multiple comparison test (p<0.0001). HD ratio ranged mostly between 80% and 90%, and more than 95% of sapling stems were of high quality, with a straight, unbroken top, non-sweep, and non-diseased stem. On average, the annual height increment of saplings was 21.9 cm at 1 year, 43.3 cm at 5 years, 54.3 cm at 10 years, and 64.3 cm at 15 years. The overall height growth with age increased smoothly. According to the analysis of covariance, the annual height growth by crown class differed significantly. The regression analysis parameters revealed that annual height growth increased with age and dominant crown class.

• Journal of IKEEE
• /
• v.22 no.3
• /
• pp.850-853
• /
• 2018

In this paper, we propose a decoding method using a balanced binary tree and a canonical Huffman tree for efficient decoding of Huffman codes. The balanced binary tree scheme reduces the number of searches by lowering the height of the tree and binary search. However, constructing a tree based on the value of the code instead of frequency of symbol is a drawback of the balanced binary tree. In order to overcome these drawbacks, a balanced binary tree is reconstructed according to the occurrence probability of symbols at each level of the tree and binary search is performed for each level. We minimize the number of searches using a canonical Huffman tree to find level of code to avoid searching sequentially from the top level to bottom level.

• Journal of Korean Society of Forest Science
• /
• v.74 no.1
• /
• pp.82-87
• /
• 1986

Noticed that large number of the Korean white pine (Pinus koraiensis S. et Z.) has lost its typical excurrent tree from by removal of apical shoot in the process of cone harvesting, the investigation and analysis for the species were made on the basis of the relationship among DBH, total height, merchantable height, and merchantable volume, compared with normally grown Japanese larch (Larix leptolepis Gordon). One hundred sample trees for each species were selected in the same aged stands for the study. Results have indicated that the pine has shown abnormal height growth pattern mainly by the disturbance of external artificial force. The pine's forked and/or crooked stems by the reason lave led the result of less merchantable volume in the same DBH classes. Consequently, the pine would have undesirable tree form in terms of timber production, unless free from apical shoot disturbances. Considered to the merit of the Korean white pine that can produce timber and pine nuts, management alternatives for the pine stand were suggested to achieve maximum rate of return for the silvicultural investment.

• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.16 no.3
• /
• pp.83-95
• /
• 2013

To understand natural regeneration and stand development after fire in mixed broadleaved-coniferous forests of Sikhote-Alin Mountains, ten sample plots of $50m{\times}50m$ size were established in 1975 and 1983 at the stands burned by wildfires in 1973 and 1982, respectively. And, the number of naturally regenerated seedlings were monitored in two $50m{\times}4m$ subplots in each plot. The most fire-sensitive conifer species is Abies nephrolepis, while Betula costata is the most fire-sensitive broadleaved tree species. The most fire-resistant species were Q. mongolica, T. taquetii and A. mono. The results of 20 and 30 years after the fire showed that pioneer tree species, e.g. Populus, Salix, and Betula, were regenerated immediately at the early stage of stand development and grew where there is a mono canopy layer with high density. On the other hand, the densities of successors, e.g. Pinus koraiensis, Picea jezoensis, Abies nephrolepis, Acer mono and Tilia taquetii, which were present in the study plots before the fire, increased gradually. Naturally regenerated tree species after forest fire by the growth rate were divided into three groups according to their annual height growth. The seral tree species (Betula costata, Betula platyphylla, Padus maackii, Populus tremula and Sarix caprea) belong to the first group and have the highest growth rate (from 40 to 96 cm per year). The late successional broad-leaved trees (Tilia taquetii, Acer mono and Quercus mongolica) belong to the second group and have intermediate annual height growth (from 3.7 to 13.5 cm per year). The late successional coniferous species (Picea jezoensis, Pinus koraiensis and Abies nephrolepis) form the third group and have the least annual height growth (from 1.4 to 3.5 cm per year).

• Korean Journal of Plant Resources
• /
• v.20 no.5
• /
• pp.442-445
• /
• 2007

Seedlings height of hybrids varied depending on mating combinations. Among the progenies from the mating combination, P. thunbergii(CN4)$\times$P. densiflora(KW29) showed the best plant growth. The mean height of this combination was 521 cm at the age of 8 years(yrs), which was 9% higher than rest of the crosses. Seedlings height of progenies using P. thunbergii(JN37) as mother tree showed 28%, 33%, and 29% higher than those of open-pollinated progenies of the mother tree at the ages of 4yrs, 6yrs, and 8yrs, respectively. On the other hand, using P. densiflora (KB5) as father tree showed 45%, 48%, and 32% higher than those of open-pollinated progenies of the father tree. This result may be caused by hybrid vigor.

• Journal of Climate Change Research
• /
• v.6 no.4
• /
• pp.379-388
• /
• 2015

The purpose of the this study was to provide basic data on reasonable management for Abies koreana in Mt. Jiri through analysis the ecological characteristics of Abies koreana forests on Seseok. Due to low soil pH (4.26), high organic matter (10.5%) and total N (0.32%), the soil properties of A. koreana forest on Seseok are different from those of other forest soil in Korea. According to the result of importance value analysis, A. koreana (70.5) for tree layer, A. koreana (37.6) and Rhododendron schlippenbachii (20.8) for subtree layer and A. koreana (12.6), Sasa borealis (11.5) and Acer pseudosieboldianum (11.2) for shrub layer were high, respectively. The species diversity of Shannon was 0.425 for tree layer, 0.869 for subtree layer and 1.320 for shrub layer. Evenness and dominance for all layers ranged from 0.365 to 0.894 and 0.187 to 0.635, respectively. Height growth according to DBH of A. koreana on Seseok was relative high. Annual mean tree ring growth of A. koreana showed up 1.372, 1.557 and 1.483 mm/yr for small, middle and large diameter tree, respectively. Considering the importance value, distribution of seedling, height growth and ring growth, A. koreana forest on Seseok in Mt. Jiri will be maintained as the major population from now on.