• Journal of Ginseng Research
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• 제32권4호
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• pp.347-356
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• 2008

Forest-grown American ginseng (Panax quinquefolius L.) is exposed to daily and seasonal light variations. Our goal was to determine the effect of understory light changes on the maximum quantum yield of photosystem II, expressed as $F_v/F_m$, and photosynthetic pigment composition of two-year-old plants. Understory light photon flux density and sunfleck durations were characterized using hemispherical canopy photography. Our results showed that understory light significantly affected the $F_v/F_m$ of American ginseng, especially during the initial development of the plants when light levels were the highest, averaging 28 mol $m^{-2}d^{-1}$. Associated with low $F_v/F_m$ during its initial development, American ginseng had the lowest levels of epoxidation state of the xanthophyll cycle of the season, suggesting an active dissipation of excess light energy absorbed by the chlorophyll pigments. As photon flux density decreased after the deployment of the forest canopy to less than 10 mol $m^{-2}d^{-1}$, chlorophyll a/b decreased suggesting a greater investment in light harvesting pigments to reaction centers in order to absorb the fleeting light energy.

• Journal of Ecology and Environment
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• 제32권2호
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• pp.87-96
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• 2009

Pinus thunbergii plantations in Pohang-si, Gyeongsangbuk-do, Korea, are of low ecological quality, with arrested succession and a high proportion of ruderal species. To improve the quality of the habitat, we created canopy gaps ($\sim42\;m^2$) and monitored changes in abiotic (light availability, canopy openness) and biotic (survival and growth of seedlings and understory communities) variables in 2007 and 2008 in plots that had received one of five types of treatment: cutting of canopy trees and removal of the understory (CU), cutting of canopy trees only (C), girdling of canopy trees and removal of the understory (GU), girdling of canopy trees (G) or control. Each treatment was applied to three replicate plots. Abiotic variables did not significantly differ among treatments. Survival rates of target species were slightly lower in the CU, G and control conditions. Based on logistic regression analysis, the only significant growth factor affecting survival was height growth. Positive effects of seedling height and leaf area growth on survival were also detected, but did not reach statistical significance. In treatment G, gradual improvement of overstory conditions and mitigation of competition by limitation of disturbance to the understory community were likely to have promoted seedling growth. There were no significant effects of gap treatments on changes in species abundance (cover and richness) and composition of understory between the study years. This result implies that the small gaps created in our study may be below the threshold size to affect understory growth. However, the results of this study are based on a short-term investigation of only two years. Long-term research is strongly recommended to clarify the effects of gap treatment on plant communities in afforested areas.

• 한국산림과학회지
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• 제112권3호
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• pp.363-373
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• 2023

산림 바이오매스 조사는 탄소흡수원으로서의 산림을 평가하고 관리하기 위해 주기적으로 수행된다. 원격탐사의 한 종류인 라이다는 적은 노동력으로 객관적인 산림 구조 정보를 획득할 수 있어, 최근 라이다(LiDAR, Light Detection and Ranging)를 이용한 산림 조사가 주목받고 있다. 본 연구에서는 임분 상하층 바이오매스 추정에 백팩형 라이다(Backpack Laser Scanning, BPLS)와 드론 라이다(Unmanned Aerial Vehicle Laser Scanning, UAV-LS)를 이용하는 방법을 제시하고 그 정확도를 평가하였다. 상층의 경우 BPLS와 UAV-LS의 흉고직경과 수고 추정 정확도를 분석하였고, 하층의 경우 BPLS 데이터에서 추출한 수직구조 변수 중 최상의 변수 조합으로 하층 바이오매스를 추정하는 다중회귀모델을 개발하였다. 그 결과, BPLS는 흉고직경을 높은 정확도로 추정하였지만(R² =0.92) 수고는 과소 추정하였다(R² =0.63, Bias=-5.56 m). UAV-LS는 BPLS보다 더 높은 수고 추정 정확도를 보였다(R² =0.91). 하층의 경우 점들의 평균 높이와 라이다 데이터를 같은 높이를 가진 10개의 층으로 나누었을 때 아래에서 네 번째 층의 점 밀도를 의미하는 변수가 선택되어 모델이 개발되었으며, 교차검증 결과 결정계수 값은 0.68로 나타났다. 본 연구의 결과는 BPLS와 UAV-LS를 이용한 임분의 상하층 바이오매스 조사 방법이 기존의 조사 방식을 효과적으로 대체할 수 있음을 시사한다.

• 한국산림과학회지
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• 제96권5호
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• pp.520-527
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• 2007

Biomass and species diversity of understory vegetation after fertilization were studied for 28-year-old Quercus acutissima plantation (MQA), 29-year-old Pinus densiflora plantation (MPD), 8-year-old Betula platyphylla var. japonica plantation after coal reclamation (YBP), and 4-year-old Pinus densiflora plantation after forest fire (YPD) in central Korea. Nitrogen + phosphorus + potassium (6:4:1) fertilizer was applied for 3 years from 2004. Thereafter photosynthetically active radiation (PAR) and understory species richness and diversity were measured in late July-early August 2006. PAR (${\mu}mol\;m^{-2}S^{-1}$) was higher at the fertilization treatment (100.9) than at the control (67.0) for MQA while was lower at the fertilization treatment (156.5) than at the control (268.7) for MPD. Total understory biomass (t $ha^{-1}$) was lower at the fertilization plot (1.8) than at the control plot (3.0) for YPD, however, there were no differences in biomass between fertilization and control plots for MQA, MPD and YBP. Total species number of understory vegetation was higher for fertilization than for control at MPD (47 vs. 45) and YPD (21 vs. 13), and was higher for mature plantations (33 vs. 37 for MQA and 47 vs. 45 for MPD) than for young plantations (16 vs. 16 for YBP and 21 vs. 13 for YPD). Species richness and diversity were higher at the fertilization treatment than at the control for MQA, YBP, and YPD while were lower at the fertilization treatment than at the control for MPD, however, the differences were not statistically significant. Our results indicate that there were no consistent patterns in light conditions, biomass and species richness and diversity of understory vegetation following fertilization. More detailed long-term studies with different fertilizer applications would be necessary to conclude the influence of fertilization on understory vegetation in the region.

• 한국산림과학회지
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• 제97권2호
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• pp.156-164
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• 2008

Recognizing the importance of the multi-purpose management of natural deciduous forest, this study was carried out to implement the partial cutting for stand regulation to examine agroforestry practice as well as other concurrent forest resource production, and to investigate the changes in stand characteristics and understory vegetation in a silvopasture practiced natural deciduous stand in the Research Forest of Kangwon National University, Korea. Three different partial cutting intensities (68.1%, 48.6%, and control) were performed in the unmanaged natural deciduous stand in order to improve the growing condition, especially light condition, for introducing some commercial herbaceous plants on the forest floor to establish agroforestry and/or silvopastoral system. Dominated by Quercus varibilis Blume (50.5%) and Quercus dentata Thum. ex Murray (42.6%), eight tree species were composed of the study forest, including poles of Pinus desiflora Siebold & Zucc and sapling of Pinus Koraiensis Siebold & Zucc. The total of 87 (13 tree species, 12 shrub species, 58 herbaceous species, and 4 woody climbers) vascular plant species were observed in study site after partial cutting treatments, while that of before partial cutting was 53 species (14 tree species, 8 shrubs species, 30 herbaceous species, and 1 woody climbers). The proportion of life form spectra in plot B was Mi (28.4%)-Na (23.0%)-Ge (17.5%)-Ch (10.8%)-He (9.5%)-MM (6.7%)-Th (4.1%). No statistically significant differences were observed in changes of life form spectra from before to after partial cutting treatment and among partial cutting gradients in this study. Partial cutting and scratching for forage sowing made plants invade easily on the forest floor, and light partial cutting (LPC) plot (500 stems/ha) had much higher number of undersory species than those of heavy partial cutting (HPC) plot (310 stems/ha) and control plot (1,270 stems/ha).

• 한국환경과학회지
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• 제15권12호
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• pp.1119-1124
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• 2006

Height-growth analysis was used to examine forest structure and compare Pterocarya rhoifolia and Fraxinus spaethiana growth characteristics within and between each species in two P. rhoifolia-dominant and two F. spaethiana established contemporaneously in the sere, species vertical stratification 25 years after stand initiation was such that P. rhoifolia dominated the overstory but F. spaethiana the understory, including that P. rhoifolia grew about 4 times more rapidly Similarly, F. spaethiana dominated the overstory but not the understory, in a stand where it established mainly by itself, 25 years after Initiation. However, comparing the two different stands, P. rhoifolia overstory heights were about two times greater than F. spaethiana. This suggests that in a disturbance regime, forest regeneration is affected by height-growth patterns such that P. rhoifolia's ability to achieverapid height growth allows it to dominate where lights growth allows it to dominate where light resources are continuously abundant.

• The Korean Journal of Ecology
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• 제27권6호
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• pp.363-367
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• 2004

Photosynthetically active radiation (PAR) beneath the forest canopy, understory species richness and diversity, and biomass were measured in a Larix leptolepis plantation seven years after thinning in Yangpyeong. Four different thinning intensities (control, $10\%,\;20\%\;and\;40\%$ stocking reduction) were applied in 1997. The current PAR values were lower than those measured four years after thinning, and PAR at the heavy thinning plots was significantly higher than that of other thinning intensities. A total of 23 species including 9 tall-trees and 14 shrubs were found for the high layer while a total of 82 species including 10 tall-trees, 29 shrubs, and 43 herbs for the low layer. Species richness and diversity generally increased with thinning intensities, and the trends were more evident for the low layer. Aboveground biomass significantly differed among thinning intensities for both shrubs and herbs. Also there was a negative correlation between biomass and the current number of stems per hectare. The current study suggested that the effects of thinning on light conditions at the forest floor, species richness and diversity and production of understory vegetation continued seven years after the treatment.

• 한국산림과학회지
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• 제98권1호
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• pp.94-105
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• 2009

아까시나무 임분은 우리나라 저지대에 주로 조성되어 있는 도입종 조림지로서, 인위적 또는 자연적 교란, 그리고 입지조건에 의해 온전한 숲의 종조성을 나타내지 못하고 있으며, 천이가 느리거나 정체되어 있다. 또한 그것의 개체들이 인접 자연림으로 침투하고 있는 문제점이 있다. 따라서, 아까시나무 임분에서의 천이를 촉진시켜 자연 식생을 회복시킬 필요가 있다. 복원 실험은 경상북도 포항시 용흥동의 아까시나무 임분에서 작은 숲틈(${\sim}57m^2$)을 조성하여 실시하였고, $5 m{\times}5m$ 방형구 내에서, 벌채 및 하층 식생 제거(CU), 벌채(C), 환상박피 및 하층 식생 제거(GU), 환상박피 (G) 및 대조구(Control)의 5개 실험구를 3반복으로 설치하였다. 각 처리구 별 수관 열림도(%), 빛(total estimated transmitted light, $mol{\cdot}m^{-1}{\cdot}day^{-1}$), 목표 종(졸참나무)의 생장(직경, 높이 및 엽면적)을 측정하였다. 하층식생의 반응(종조성 및 종다양성)은 각 처리구에 영구 소방형구를 설치하여 측정하였고, 피도변화, Multiresponse Permutation Procedures (MRPP) 및 Detrended Correspondence Analysis(DCA)를 통하여 분석하였다. 숲틈 조성 후, 광환경은 처리구 별로 뚜렷한 차이를 나타내지 않았고, 수관 열림도는 CU, C, GU, G, Control의 순으로 높았다. 졸참나무 유묘의 생존은 수고 및 엽면적 생장과 유의한 상관을 나타내었다. 목표 종의 생장은 대조구와 비교하여 처리 후 증가하였다. 하층식생의 종조성 및 종다양성은 유의한 변화를 나타내지 않았지만, 후자의 경우 약간 감소하였고, 각 소방형구의 총 피도는 약간 증가하였다. 아까시나무림에 대한 생태적 복원의 한 방법으로서 작은 규모의 숲틈을 조성한 결과, 급격한 환경 변화를 발생시키지 않았고, 수고 생장을 촉진할 수 있는 가능성을 나타내었다. 복원 교란에 대한 하층식생의 반응은 연구지역의 특성을 반영하는 것으로 생각된다. 본 연구의 결과는 장기적인 관찰이 필요하며, 최소한의 교란을 통한 삼림 관리 및 복원 기법으로 발전할 수 있는 가능성을 보였다.

• 한국환경과학회지
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• 제20권12호
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• pp.1599-1605
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• 2011

To evaluate heat environment surrounding plants diurnal change of leaf temperature in the broad-leaved deciduous and evergreen trees was measured with microclimatic environmental factors including global solar radiation, and upward and downward long wave radiation. Maximum daily solar radiation was 961.2 and 976.3 w/$m^2$ in August 9 and 23, respectively. Upward long wave radiation was slightly higher than downward long wave radiation, showing 404.2 w/$m^2$ in August 9 and 394.5 w/$m^2$ in August 23. In addition, daily maximum vapor pressure deficit was 5.42 and 6.84 kPa in August 9 and 23, respectively, indicating high evaporative demand. Quercus glauca and Acer mono was differently responded to changing light regimes. On August 9, leaf temperature at the top-positioned leaves of Acer plants was higher than air temperature as well as those of Quercus plants in the morning. This indicates that stomata in Acer plants were closed by heat stress or water stress in the morning, while Quercus plant maintained active transpiration by opening stomata. These results indicated that improved light regimes such as gap opening in the closed forest may not always affect positively in the physiology of understory plants.

• Journal of Forest and Environmental Science
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• 제32권1호
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• pp.74-81
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• 2016

Classified into sub-tree of the growth-form, Acer pseudosieboldianum and Carpinus cordata hardly reach the uppermost canopy with limited height growth potentiality in the natural deciduous forest. However, the two species usually dominate lower stories of the forest, playing an important role in overall ecological characteristics in the forest. Based on the vegetation data of 106 $20m{\times}20m$ sample plots in Mt. Jumbong area, this study was carried out to evaluate ecological constitution by several quantitative analysis so as to understand the mechanism of the natural deciduous forest. The results indicated that individuals of A. pseudosieboldianum and C. cordata were absent or few in overstory, but emerged the most dominant species in midstory and understory, providing adequate proof of the ecological importance. The comparison of indices of succession between presented and predicted values in midstory did not make much difference, suggesting that the species composition would not change much and come close to steady state in midstory and understory. The pair combination of species association noted that A. pseudosieboldianum had significant positive association with C. cordata, Quercus mongolica, and Tilia amurensis had significant positive association with A. pseudosieboldianum, A. pictum subsp. mono and Fraxinus mandshurica but negative association with F. rhynchophylla. Being compared with other major canopy tree species in the study forest, the target species of A. pseudosieboldianum and C. cordata had strong regeneration strategies, partially characterized by large number of saplings and pole sized trees and high ratio of live crown, which indicated high shade tolerance to survive in the limited amount of light under the canopy. Even though A. pseudosieboldianum and C. cordata do not reach and occupy the canopy layer mainly due to the inherent growth form, they would have highest competitive potentiality to prosper and dominate in the midstory of the natural deciduous forest.