• Journal of Korean Society of Forest Science
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• v.103 no.4
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• pp.613-621
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• 2014

This study was conducted to estimate the changes of stand diversity before and after applying three different silvicultural treatments such as selection cutting system, two-storied system, and shelterwood system. Data were collected in the natural deciduous forests in Pyungchang of Gangwon Province, Korea. Nine permanent sampling plots of 0.09 ha were established in the forests and the each of silvicultural treatments was applied to three sampling plots, respectively. Some tree variables were measured in each stand before and after the silvicultural treatments were applied. With these data, stand attributes were estimated in each stand before and after the silvicultural treatments. In this study, two different indices related to each of stand diversity indices such as contagion, DBH-difference, height-difference, and mingling were estimated and compared to analyze the differences of stand diversity among the stands before and after silvicultural treatments. As a result, total eight stand diversity indices were used to analyze the differences among structures of stands managed by three different silvicultural treatments. Duncan's multiple range test and t-test were then employed to statistically analyze the difference of stand diversity among the stands. The results revealed that stand structures seem to be improved after applying the silvicultural treatments. There are significant differences in the stand diversity indices between before and after silvicultural treatments for each stand. According to the evaluation of stand diversity indices, it was confirmed that spatial structure of the stands was improved by applying the silvicultural treatments.

• Korean Journal of Environment and Ecology
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• v.29 no.5
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• pp.791-802
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• 2015

The study was carried out to analyze vegetation structure of Mt. Eungbok located in Jochimryeong to Shinbaeryeong of the Baekdudaegan mountain range. The survey for 25 plots was conducted from April 2012 to August 2013 in the permanent plots using phytosociological analysis. As a result, the vegetations were classified into four vegetation units. In species composition, they were classified into Quercus mongolica community group divided into 2 community such as Ulmus laciniata community and Corylus sieboldiana var. mandshurica community, U. laciniata community was subdivided Rhododendron schlippenbachii group and Rubus crataegifolius group(into Viola albida subgroup, Rubus oldhamii subgroup). In terms of Importance values according to layer-specific and altitude of ridge, Q. mongolica was the highest importance value of tree layer and Acer pseudosieboldianum was highest importance value of sub tree layer. Therefore Q. mongolica and A. pseudosieboldianum could likely remain in the future of tree layer and sub tree layer respectively. Analysis of dominance most value of vegetation are on about 0.3. In ridge area was a species diversity result, vegetation unit 3 showed the highest value 0.974 and vegetation unit 1 showed the lowest value 0.725. Based on the interspecific association showed four types which were coincident with differential species and character species on the constancy table. Specially type I plant species were mostly differential species and the characteristic species, which appeared in the Rhododendron schlippenbachii community classified phytosociologically, and type III plant species were mostly the species appearing in the Corylus sieboldiana var. mandshurica community growing in the relatively.

• Journal of Korean Society of Forest Science
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• v.104 no.3
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• pp.427-433
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• 2015

This study was conducted to provide a method of establishing two-storied forests by the adjustment of stand structures in natural deciduous forests of Pyeongchang area. Three permanent sampling plots of 0.09 ha were established in study site and some tree variables were measured in each sampling plot before the treatment of two-storied system. Stand attributes and stand structures before treatment were estimated based on the data measured in sampling plots. The results indicate that the current stand status is different from typical stand structures of two-storied forests. A simulation technique was applied to predict stand attributes and stand structures after the treatment of two-storied system. Results suggest that significant time is required to accomplish target stand structures even after applying the treatment of two-storied system. Number of trees in the upper canopy class after treatment was predicted to be 170 trees/ha, which adequately meets the target of two-storied forests. It was predicted, however, that the lower canopy class trees has much less trees compared with the typical stand structures of two-storied forests. This problem could be solved with ingrowth of infant trees over time or by under-planting of tolerant species. It is confirmed that the target growing stock volumes of the upper canopy class should be approximately $150m^3/ha$ considering stand status after treatment. It is predicted that twenty years of conversion period is required to accomplish this goal. The changes in stand structures over time should be assessed based on stand inventory carried out every five years, and additional treatments for inducing two-storied forests should be applied if necessary.

• Journal of Korean Society of Forest Science
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• v.90 no.5
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• pp.650-662
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• 2001

The growth and yield models for five different kinds of natural forest types were systemically developed in the natural Broadleaved-Korean pine Forests in Northeast China. The data were collected from 359 temporary plots and 58 permanent plots with area ranged from 0.06 ha to 1.0 ha, ranging in stand age from 43 to 364 years. The Site Class Index (SCI) was introduced to evaluate site quality and the Crown Competition Factor (CCF) was selected as a measure of stand density for the mixed natural forest. The Chapman-Richards function was adopted to develop SCI equation and height-diameter curve. The Schumacher growth function was selected as base model to develop the DBH, basal area, and stand volume growth models by using re-parameterized method. In modeling mean DBH and basal area growth, it was found that the asymptotic parameter A of Schumacher function was exponentially related to site quality (SCI) and stand density (CCF). The rate parameter k was related to stand density and it was independent of SCI. Several validation measures for predicted stand variables were evaluated in the growth and yield models using independent data sets. The results indicated that relative mean errors (RME) in predicted stand attributes were less than ${\pm}5%$ and the estimated precision values of the stand variables were all greater than 95%.

• Korean Journal of Environment and Ecology
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• v.22 no.5
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• pp.514-520
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• 2008

The permanent monitoring plots were installed in 2001 for long-term monitoring the structure of forest communities at the Piagol(Valley) and Daeseonggol(Valley) in the Jirisan National Park, and monitored the forest structure in the studied sites in 2001 and 2006. Dominant species at Piagol and Daeseonggol was Carpinuslaxiflora and Quercus mongolica respectively. Based on the distribution of major species' stem diameter, the species diversity index was higher in Piagol than that of Daeseonggol. The distribution of diameter in major tree species in the studied sites showed a stable plant community structure. The forest of Piagol, which is positioned in the valley, showed a quite a different composition of species from that of Daeseonggol, which is positioned on the slope. In the last five years, the overall grows rate of Piagol Forest decreased by $6.4m^2$ per hectare, while Daeseonggol Forest increased by about $8.27m^2$ per hectare. I think that this is because of the fact that a lot of large old trees have died.

• Journal of Ecology and Environment
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• v.30 no.4
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• pp.325-330
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• 2007

Recognizing the ecological importance of forest gap formation for forest community structure, we examined the differences in species diversity between forest gaps and closed canopy areas for trees and shrubs in three developmental stages (seedling, sapling I, and sapling II) in a typical mixed broadleaved-Korean pine forest. We randomly placed 100 sample plots ($2{\times}2m$ for seedling and sapling I, and $5{\times}5m$ for sapling II) in forest gap and closed canopy areas of a 9 ha permanent sample plot for vegetation surveys of plants of each developmental stage in each habitat type. Even though the formation of forest gaps encouraged the occurrence of gap-dependent species and increased overall species diversity, there were no significant differences in species richness among the three developmental stages for both tree and shrub species (p>0.05). Comparing the two types of sites, statistical tests revealed no difference in species richness for trees, but highly significant differences (p<0.01) between forest types for shrubs for seedlings and sapling I, but not sapling II. Analysis of variance test indicated that there were no significant differences in species diversity among the three developmental stages of tree species (p>0.05) for both Simpson and Shannon indices. The variance for shrub seedlings was significantly different between forest gaps and closed canopy areas, but not for sapling I and sapling II. The analysis showed that the species diversity in forest gaps was significantly different from that of closed canopy areas for seedling and sapling I (p<0.01), but not for sapling II (p>0.05).

• Journal of Ecology and Environment
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• v.34 no.2
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• pp.157-165
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• 2011

This study was conducted to determine the characteristics of gaps and natural regeneration of trees on Mt. Makiling, the Philippines. Canopy gaps in or around two 1-ha permanent plots and on 3-km line transects were investigated. Most of the gaps studied were formed or affected by Typhoon Milenyo, which hit the study site in September 2006. The most frequent mode of gap maker death was snap-off, whereas uprooting was relatively less important. The most frequent gap maker was balobo (Diplodiscus paniculatus) followed by magabuyo (Celtis luzonica) and katmon (Dillenia philippinensis). In contrast, the most frequent gap filler was magabuyo (C. luzonica). At the sapling layer, the most important species was magabuyo (C. luzonica), but there was a high proportion of lianas and palms. Most of the gaps had leaf area index (LAI) values between 3 and 5. A clear trend of a decrease in gap size and an increase in LAI was observed for 2 years from 2007 to 2009. New seedlings emerged very abundantly during the same time period. The rapid changes in the gaps were partially due to the excellent capability of tropical trees to resprout after the crown or stem was damaged by the typhoon. This study on gap dynamics may contribute to a better understanding of the natural regeneration process of trees in tropical rainforests.

• Journal of Korean Society of Forest Science
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• v.89 no.4
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• pp.463-469
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• 2000

Douglas-fir (Pseudotsuga menziesd Mirb. Franco) is highly regarded as a commercial timber species throughout the world in part due to its fast growth relative to many other species. In this study, basal area per hectare equation for Douglas-fir plantations in Southland of New Zealand has been developed based on medium measurement cycles of permanent sample plots data set. The function was developed using the algebraic difference equation method, and various sigmoid-shaped projection equations were used. Parameter estimation was obtained by non-linear routine of the SAS. As a result, of the functions tested a variant of the Schumacher polymorphic function including site index and thinning term as predictor variables showed the higher precision of the fitting. The results indicate that site index is positively correlated with basal area growth. And the thinning term was found to be useful to increase precision of the model.

• Journal of Ecology and Environment
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• v.33 no.1
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• pp.67-77
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• 2010

Stand structure and spatial associations of the dominant tree species in Quercus mongolica stands were investigated to understand interspecific relationships and the persistent dominance of Q. mongolica. We examined the species composition, DBH (diameter at breast height) distribution, and spatial distribution of trees (${\geq}\;2.5\;cm$ DBH) in two permanent $100\;m\;{\times}\;100\;m$ plots in Q. mongolica-dominant stands on the western part of Mt. Jiri. Ripley's K-function was used to characterize the spatial patterns and associations of dominant tree species. Q. mongolica showed a continuous and reverse-J shaped DBH distribution with clumped spatial distribution in both study sites. Q. mongolica and Abies koreana exhibited a negative association implying potential interspecific competition. The positive spatial association between Q. mongolica and Alnus hirsuta var. sibirica and Fraxinus sieboldiana were affected by site characteristics: limited habitat conditions with a large proportion of rock surface. Our results suggest that interactions among species were complex and ranged from positive to negative. Differences in stand and site characteristics and regeneration mechanisms among the species play an important role in regulating their spatial distribution patterns, while competition between individuals also contributes to spatial patterning of these communities. The high density and the early developmental stage of spatial distribution and structural characteristics of Q. mongolica and the relatively low importance values of other species in the stands imply that Q. mongolica will remain dominant in the study sites in the near future.

• Journal of Korean Society of Forest Science
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• v.88 no.2
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• pp.142-148
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• 1999

This research describes the construction of a site index equation and curves for Douglas-fir plantation (Pseudotsuga menziesii Mirb. Franco) in Nelson, New Zealand. The data sets of 146 Permanent Sample Plots (PSP) were used to build the model, and it was developed using the difference equation method. Parameter estimates were obtained using the non-linear routine of the SAS, PROC NLIN procedure. Of the models tested, a variant of the Schumacher polymorphic yield function showed the higher precision of fitting. About 95% of the observations used to fit the model could be predicted within ${\pm}1.2m$ of the actual values. Therefore, polymorphic family of site index curves, which reflect different shapes for the different site index classes, were derived from the Schumacher equation. It was found that the polymorphic site index equation was more accurate than the anamorphic equation in this study.