Kaempferi Plantations Research Articles

리기다소나무와 낙엽송 인공림의 지역 및 임령에 따른 토양 특성

본 연구는 우리나라 침엽수림 면적의 약 1/3을 차지하는 리기다소나무와 낙엽송 인공림을 대상으로 지역 및 임령에 따른 토양의 물리 화학적 특성을 파악하여, 이들 인공림의 벌채 후 진행되는 조림 사업에 필요한 기초 자료를 얻고자 수행하였다. 두 인공림에 대한 토양 특성은 기존 보고된 문헌자료와 2년(2010, 2011년) 동안 전국 국유림 내에서 조사 분석한 토양 특성 결과를 바탕으로 지역 및 임령별로 나누어 분석하였다. 리기다소나무 인공림 내 전라남도 지역과 낙엽송 인공림 내 경상북도 지역의 토양 특성이 동일 수종의 임분 내 다른 지역보다 양호하였다. 두 인공림의 토성은 대부분 양토 혹은 사질양토였고, 토양 pH 값은 리기다소나무와 낙엽송 인공림에서 각각 4.86, 4.87로 나타났으며, 토양 pH는 임령 증가에 따라 일정한 경향을 보이지 않았다. 리기다소나무와 낙엽송 인공림의 전질소 농도(%)는 각각 0.21, 0.28이었고, 유효인산 농도(<TEX>$mg{\</TEX><TEX>cdot}kg^{-1}$</TEX>)는 각각 11.00, 13.32로 나타났다. 낙엽송 인공림 내 전질소, 유효인산, 유기물 농도 및 양이온치환용량은 리기다소나무 인공림보다 높고, 은, 임령이 증가함에 따라 농도가 증가하는 경향을 보였으며, 치환성양이온(<TEX>$Ca^{2+}$</TEX>, <TEX>$Mg^{2+}$</TEX>, <TEX>$K^+$</TEX>)은 토양 pH와 정의 상관관계를 나타냈다. 두 인공림에 대한 토양 특성 분석 결과는 리기다소나무 벌채와 낙엽송 주벌 실시 후 요구되는 조림지 관리에 적용할 수 있으며, 토양 양분 특성 등을 고려한 맞춤형 조림 수종 선정과 조림지 관리에 활용하여 지속적인 산지 자원화에 기여할 수 있을 것으로 판단된다. This study was performed in Pinus rigida and Larix kaempferi plantations which occupy approximately 60% of artificial forest area in Korea. The objective of this study was to know the differences in soil physical and chemical properties between both plantations. Soil physical and chemical properties from published literature and analyzed soil data in national forest in 2010 and 2011 were analyzed by plantation regions and stand age of 5 years unit. Jeollanamdo in Pinus rigida plantations and Gyeongsangbuk-do in Larix kaempferi plantations showed higher soil chemical properties than those of other regions. Soil texture in both plantations was almost loam and sandy loam. Mean soil pH in Pinus rigida and Larix kaempferi plantations were 4.86 and 4.87, respectively and there was no relationship between soil pH and stand age. The mean concentrations of total nitrogen (%) and available phosphorus (mg <TEX>$kg^{-1}$</TEX>) were 0.21 and 11.00 for Pinus rigida plantation and 0.28 and 13.32 for Larix kaempferi plantation. In Larix kaempferi plantation, total nitrogen, available phosphorus and organic matter concentrations and C.E.C. were higher than those in Pinus rigida plantation and showed positive relationship with stand age. This positive relationship was also revealed between the exchangeable cations and soil pH. The results of this study provide an informative data in selecting tree species for planting and contribute to the establishing forest management plan for the maintenance of sustainable forests resources.

Community Structure of Soil Macrofauna of Larix kaempferi Plantation in Western Qinling Mountains

Long-term human disturbance in the secondary forest ecosystem would have profound impacts on belowground ecological processes,whereas the community structure and functional diversity of soil fauna would be sensitive to the changes of belowground ecological processes,thus being an indicator of the changes.In this study,the method of hand-sorting was adopted to investigate the density of the soil macrofaunal community across three forest types of 10-year-old,20-year-old and 32-year-old Japanese conifer(Larix kaempferi) plantation in the western Qinling Mountains.PCA and one-way ANOVA analysis were applied to analyze the community structure and trophic group composition of soil macrofauna in different developmental stages of Japanese conifer plantations.Our results demonstrated that the density of the soil macrofauna community in the 10-year-old Japanese conifer plantation was significantly higher than that in the 20-year-old and 32-year-old Japanese conifer plantations,and the density of the soil macrofauna community in the 32-year-old Japanese conifer plantation was significantly higher than that in the 20-year-old Japanese conifer plantation.However,the diversity index and evenness index in the 20-year-old Japanese conifer plantation was significantly higher than that in the 10-year-old and 32-year-old Japanese conifer plantations.We also found a similar pattern in the abundance and group richness of ‘detritivores+ominivores' in different developmental stages of Japanese conifer plantations.There were significant changes of Diplopoda,Carabidae,Diptera larvae and Formicidae across the three development stages of Japanese conifer plantation,which can be used as indicators of the change in soil environments.

Ecological Changes of the Larix kaempferi Plantations and the Restoration Effects Confirmed from the Results.

Ecological Changes of the Larix kaempferi Plantations and the Restoration Effects Confirmed from the Results.

Health Evaluation of Larix Kaempferi Plantation Ecosystem Based on BP Neural Network Model

Based on the basic theory of the forest ecosystem, we build the index system to evaluate forest ecosystem health from the stand-scale and take advantage of improved BP neural network to evaluate the ecosystem health of Larix Kaempferi plantation in the Liaodong area quantitatively. And then we analyze the stand-scale health grade status according to different slope aspect, forest age, average tree height and altitude. The results indicate that we make the satisfactory process to research the complex forest ecosystem using the improved BP neural network. The improved BP neural network which uses the momentum-adaptive learning rate adjustment algorithm and L-M learning rules decreases iteration times, makes the convergence speed very fast and improve the precision.

Differences in soil aggregate, microbial biomass carbon concentration, and soil carbon between Pinus rigida and Larix kaempferi plantations in Yangpyeong, central Korea

This study was conducted to examine the soil aggregate distributions and their relationship with microbial biomass carbon (C) concentration and soil C in Pinus rigida and Larix kaempferi plantations. Soil samples of 0–10 cm, 10–20 cm, and 20–30 cm depth were collected and the microbial biomass C concentration was measured. The soils were then classified into four aggregate size classes by wet-sieving procedure [large macroaggregate (>2000 μm), small macroaggregate (250–2000 μm), microaggregate (53–250 μm), and silt-plus-clay (<53 μm)] and the C content of each aggregate size class was analyzed. The L. kaempferi plantation contained more macroaggregate over 250 μm than the P. rigida plantation did. The mean weight diameter (MWD) of the soil aggregate up to 30 cm depth was 1.26 mm and 1.45 mm in the P. rigida and L. kaempferi plantations, respectively, and it decreased with soil depth. The microbial biomass C concentration up to 30 cm depth was 510 μg C g soil−1 for the P. rigida plantation and 764μg C g soil−1 for the L. kaempferi plantation, and it was greatest in the surface soil in both plantations. The mean soil C concentration up to 30 cm depth was 2.00% for the P. rigida plantation and 2.88% for the L. kaempferi plantation. In both plantations, the soil C concentration was higher in the surface soil than in the deep soil. However, there was no significant difference of C concentration among the soil aggregate size classes. The soil C content up to 30 cm depth in the P. rigida and L. kaempferi plantations were 47.69 Mg ha−1 and 61.49 Mg ha−1, respectively, and were also higher in the surface soil than in the deep soil. In both plantations, macroaggregate contained more Ccontent than microaggregate did. The microbial biomass C and soil C concentrations were significantly higher (P < 0.05) in the L. kaempferi plantation than in the P. rigida plantation due to the effect of species difference. The MWD and C content tended to be greater in the L. kaempferi plantation than in the P. rigida plantation, but the differences were not significant. In this study, the soil aggregate size, microbial biomass C and soil C concentrations were positively correlated with one another.

Effects of thinning and excluding deer browsing on sapling establishment and growth in larch plantations

Monoculture plantations with rapidly growing trees are often used for reforestation schemes on abandoned land. There is evidence that in some cases, reforestation facilitates forest succession toward natural species composition. However, the success of a scheme varies according to site conditions, and systematic investigations are required for adaptive management. Monoculture plantations were used to reforest abandoned pastures at the study site in Hokkaido, northern Japan. At the study site—a 40-year-old nonnative larch (Larix kaempferi) plantation—the effects of thinning and deer-browsing exclusion treatments on the demography of understory saplings were analyzed to achieve appropriate management planning for reforestation. After deer-browsing exclusion, saplings of various species became established, and species composition corresponded closely to that of a natural conifer–broadleaved mixed stand. Saplings of shade-tolerant species, such as Abies sachalinensis and Acer mono, were abundant. Thinning influenced the demography of saplings over an 8-year period and significantly affected the height growth rate of A. sachalinensis saplings, which show strong variations in response to varying light conditions. There were also negative effects of thinning, such as increased mortality and decreased height growth rate of broadleaved saplings, the growth of which was suppressed by facilitated growth of A. sachalinensis. Thus, treatments used for reforestation must take into account differences in demographic traits of tree species by including long-term monitoring.

A weeding-duration model for Larix kaempferi plantations in Hokkaido, northern Japan

In this study, a weeding-duration model for Larix kaempferi plantations was developed that employs a generalized linear model. The number of years that weeding is necessary is the response variable, and elevation, slope, maximum snow depth, annual precipitation, geological type, soil type, site index, slope aspect, and vegetation type are explanatory variables. Among the explanatory variables, geological type, soil type, slope aspect, and vegetation type are categorical data. We assumed a Poisson distribution for the response variable. The link function was log. Among the models that could be developed from these variables, we chose the model with the smallest Akaike's information criterion (AIC). The weeding-duration model can be written as follows: years that weeding is necessary = Exp (−0.0172833 × site index + 0.0014053 × maximum snow depth (cm) + 1.7417731). The results of this study imply that weeding of Larix kaempferi plantations is needed for more years as the maximum snow depth increases and fewer years as the site index increases. This model is useful for cost–benefit analyses of afforestation or reforestation with Larix kaempferi.

Relationship among soil aggregate, microbial biomass and soil carbon contents in Pinus rigida and Larix kaempferi plantations in Yangpyeong, central Korea

Relationship among soil aggregate, microbial biomass and soil carbon contents in Pinus rigida and Larix kaempferi plantations in Yangpyeong, central Korea

Influence of thinning on carbon storage in a Japanese larch (larix kaempferi) plantation in Yangpyeong, central Korea

This study was conducted to determine the carbon (C) contents in a Japanese larch (Larix kaempferi) plantation with four different thinning intensities over 12 years in Yangpyeong, central Korea. Thinning was applied in April of 1997 [control, no thinning (2250 trees/ha)], light thinning (T10, 10% thinning, 2000 trees/ha after thinning), moderate thinning (T20, 20%thinning, 1750 trees/ha after thinning), and heavy thinning (T40, 40% thinning, 1200 trees/ha after thinning)]. We measured individual tree DBH (cm) in November, 2009 and calculated biomass using the allometric regression equation. Forest floor (litter and coarse woody debris (CWD)) and soils, litter and soils up to 30 cm were collected and analyzed. Even though tree survival rate during 12 years was highest in the heavy thinning plot (T40), vegetation C content (Mg C/ha) was significantly higher in the light thinning plot (T10) than the other plots: 58.5 for control, 64.9 for T10, 60.4 for T20, and 55.8 for T40, respectively. Moreover, total soil C content (Mg C/ha) was higher in the moderate thinning plot (T20), however, there was no significant difference among the other plots; 56.2 for control, 57.8 for T10, 63.7 for T20, and 62.3 for T40. C contents of forest floor (litter plus CWD) were largest in the control plot, which might be influenced by the individual tree species competition; 11.9 for control, 10.2 for T10, 10.1 for T20, and 6.6 for T40, respectively. Total ecosystem C content was higher in the moderate thinning plot (T20) than those in other thinned and unthinned plots: 125.2 for control, 131.2 for T10, 132.4 for T20, and 125.9 for T40, respectively. Moderate thinning treatment (T20) seemed more effective to conserve total ecosystem C content while the individual tree growth (mean DBH and height) was higher in the heavy thinning plot (T40).

Diversity of naturally regenerating tree species in the overstorey layer of Larix kaempferi plantations and abandoned broadleaf coppice stands in central Japan

Forestry, Vol. 83, No. 3, 2010. doi:10.1093/forestry/cpq011 For Permissions, please email: journals.permissions@oxfordjournals.org Advance Access publication date 12 May 2010 Introduction One-quarter of Japan’s land area is occupied by plantations (10.4 million ha in 2001). In many plantations, active management or ‘tending’ (weeding and thinning) of the forests has been abandoned due to declining timber prices and an aging workforce. Consequently, the extension of plantation rotation periods has become an increasingly common means of producing more valuable timber in maturing stands and of maintaining biological diversity. Species diversity in forests is strongly affected by the kinds of forest management interventions employed, and the impacts of these interventions can have a marked and variable effect on the structure and functioning of different forest ecosystems (e.g. plantations, coppice forests). Studying the effects of forest management is considered an important aspect of sustainable ecological forest management because it promotes an understanding of the relationship between stand structure and species composition (Kerr, 1999; Cummings and Reid, 2008). Since stand age can also influence the species composition of forest stands, a chronosequence approach is increasingly being applied to studies of how stand age and stand management practices influence stand composition (Hunt et al., 2003; Nagaike et al., 2006a). Plantations would be designated for ecological restoration when it is recognized that they were established on sites that are unsuitable for timber production and where there is a need for conserving biological diversity (Zerbe, 2002; Masaki et al., 2004; Cummings and Reid, 2008). The change in species composition associated with stand age in plantations differs with that in naturally regenerated stands since different regeneration processes (i.e. planting vs natural regeneration) and tending procedures (e.g. weeding and thinning) are employed. Stand age of plantations is important because it is directly related to the amount of timber produced and the cutting rotation employed in a landscape. When considering the requirements of ecological restoration initiatives, it is important to set the end points of either natural or historical conditions as a target for the restored forests (Stanturf, 2005) and establish baseline data for the composition of naturally regenerated tree species in the subject plantations. In addition, as another end point, the plantations should also be compared with natural forests as the end points, which represent the natural condition of forests in a region. Forest management (e.g. directly removing trees and shrubs by thinning and weeding) is known to affect each stratum of the forest differently (Nagaike et al., 2003; Diversity of naturally regenerating tree species in the overstorey layer of Larix kaempferi plantations and abandoned broadleaf coppice stands in central Japan

Effects of altitudinal gradient on species composition of naturally regenerated trees in Larix kaempferi plantations in central Japan

Species composition and community structure of naturally regenerated trees in Larix kaempferi plantations and natural forests were compared in relation to altitudinal gradient. Fifty-nine L. kaempferi plantations and 26 natural forest stands including old-growth and secondary forests were selected from 1300 to 2000 m a.s.l. in Mt Kushigata of central Japan. Vegetation plots (10 × 10 m) were established in each stand (85 plots in total). Species composition differed significantly between forest types, particularly on high altitude plots. Some species were significantly biased to natural forests, while no species were biased to plantations. Although some species that responded significantly to altitude were common to both forest types (e.g., Acer ukurunduese, Castanea crenata, and Fraxinus lanuginose f. serrata), some differed between forest types (e.g., Fagus japonica, Prunus maximowiczii, and P. nipponica). Thus, plantation management altered species responses to altitude. Altitude should be considered when planning and carrying out forest ecological restoration in plantations, because species composition of naturally regenerated trees has already been changed by past plantation management. In particular, attention should be paid to ecological restoration at high altitude.

Snag abundance and species composition in a managed forest landscape in central Japan composed of Larix kaempferi plantations and secondary broadleaf forests

Larix kaempferi is the main plantation species in the low-snow, cool-temperate zone of Japan. I studied L. kaempferi plantations of various stand ages in central Japan to examine and compare the effect of stand age on the abundance, size, and species composition of snags (standing dead trees) compared to those in secondary broadleaf forests. Plantations that were older than the standard rotation age had more and larger snags than young plantations, and the species diversity of snags was positively correlated with stand age. Because the density of living planted L. kaempferi showed little correlation with snag variables, whereas that of naturally regenerated tree species was positively correlated with snag variables, the density dependence of snag occurrence was stronger in naturally regenerated trees than in planted L. kaempferi. Snag species that were positively correlated with stand age were the main species in secondary broadleaf forests in this area. Basal area, density, and number of species of snags in standard-rotation plantations were significantly lower than in long-rotation plantations and secondary broadleaf forests. Long-rotation plantations are useful for retaining snags compared to standard-rotation plantations.

Regeneration of broad-leaved trees in abandoned forests after clear-cutting of Larix kaempferi plantations in Hokkaido

Regeneration of broad-leaved trees in abandoned forests after clear-cutting of Larix kaempferi plantations in Hokkaido

Changes in plant species diversity over 5 years in Larix kaempferi plantations and abandoned coppice forests in central Japan

We studied the forest layers (understory and overstory) of two forest types ( Larix kaempferi plantation and secondary, broad-leaved, abandoned coppice forest) according to stand development in order to examine differences in the changes in plant species diversity over the 5 years from 1999 to 2004. Increased stem density in the plantations had decreased the species diversity in the overstory, whereas species diversity in the understory was stable. However, species replacement was greater in the understory than in the overstory for both forest types. In the understory of both forest types, more small-animal-dispersed species and tall tree species had colonized, and the frequency of occurrence of some bird-dispersed tall tree species had increased. These results support our previous studies, which used a chronosequence approach and found that older plantations contained more animal-dispersed tall tree species than young plantations.

질소와 인 시비가 리기다소나무와 낙엽송의 낙엽 생산량 및 양분 동태에 미치는 영향

본 연구는 경기도 양평지역 내 서로 인접하여 있고 동일한 입지 환경 위에 생육하고 있는 41년생 리기다소나무와 낙엽송 조림지를 대상으로 질소와 인 시비처리가 리기다소나무와 낙 엽송의 낙엽 생산량 및 양분 동태에 미치는 영향을 구명하기 위하여 수행되었다. 낙엽 생산량은 시료채취 시기와 수종간에 통계적으로 유의성이 인정된 반면, 시비 처리간에는 유의적인 차이가 없었던 것으로 나타났다. 연간 낙엽 생산량은 리기다소나무가 6,377 kg/ha 그리고 낙엽송이 4,778 kg/ha이었다. 낙엽 내 양분농도는 낙엽송이 리기다소나무에 비해 높았으며, 두 수종 모두 처리구간에 유의적인 차이가 있는 것으로 나타났다. 또한 낙엽 내 양분 농도는 낙엽송에서의 Ca 함량을 제외하고 두 수종 모두 연중 낙엽 생산량이 가장 많았던 늦가을에서 가장 낮았으며, 연중 낙엽 생산량이 가장 적었던 여름에 가장 높았던 것으로 나타났다. 또한 리기다소나무와 낙엽송 임분 임상의 총 유기물 함량은 24,296 kg/ha, 그리고 10,763 kg/ha였으며, 임상 내질소와 인의 함량은 리기다소나무가 126, 10 kg/ha, 그리고 102, 8 kg/ha로 각각 나타났다. Effects of nitrogen and phosphorus fertilization on nutrient dynamics and litterfall production were determined in adjacent 41-year-old plantations of Pinus rigida Miller and Larix kaempferi Gordon on a similar soil in Yangpyeong, Gyeongggi Province. Litterfall production were significantly different among sampling dates and between the tree species, whereas it was not significantly different among the treatments. Total annual litterfall production was 6,377 kg/ha for P. rigida and 4,778 kg/ha for L. kaempferi, respectively. Litterfall nutrient concentrations of L. kaempferi were higher than those of P. rigida. For both tree species, litterfall nutrient concentrations were highest in summer when the least litterfall production occurred, and lowest in late-autumn when the greatest litterfall production occurred, except for Ca in the L. kaempferi stand. The amount of total organic matter in the forest floor of P. rigida and L. kaempferi plantations were 24,296 kg/ha and 10,763 kg/ha, respectively. Forest floor N and P contents were 126, 10 kg/ha for P. rigida and 102, 8 kg/ha for L. kaempferi, respectively.

Plant Species Diversity in a Managed Forest Landscape Composed of Larix kaempferi Plantations and Abandoned Coppice Forests in Central Japan

Abstract To evaluate the role of each forest type and stand in an intensively managed forest landscape in terms of vascular plant species diversity, we studied a landscape composed mainly of Larix kaempferi plantations with different stand ages and secondary broad-leaved abandoned coppice forests in central Japan, which were both codominant in the study landscape. All species diversity indices were significantly higher in plantations than in secondary forests. In the detrended correspondence analysis diagram, the younger plantations were distributed far from the older plantations, and the older plantations were located close to broad-leaved secondary forests. The relative frequency of occurrence and number of weed species were both negatively correlated with stand age for plantations, while the number of species with bird-dispersed seeds was positively correlated. Therefore, these changes along the stand-age gradient for specific ecological attributes of species created the similarity in community composition found between older plantations and secondary forests. Because the relative frequency of occurrence and number of tall-tree species and the relative frequency of species with bird-dispersed seeds were significantly higher in secondary forests than in plantations, restoring these species in plantations would likely be a long process.

Stand structure and composition of a 60-year-old larch (Larix kaempferi) plantation with retained hardwoods

Tree retention is understood as a key practice in creating complexity, leading to heterogeneity in resources and habitats in managed stands. In this article, we clarify the long-term effects of tree retention on stand structure and tree-species composition in a 60-year-old Larix kaempferi plantation in central Japan. In our study plot (1.5ha) there were 18 stems/ha of retained trees (determined by tree-ring analysis), mostly Quercus crispula. We conducted spatial analyses and tested the hypothesis that tree abundance, size structure, and species composition and diversity change with distance from the retained trees. Near the retained trees, L. kaempferi showed a reduction of 40%–60% in basal area, due presumably to the shading effect. In contrast, the nearby area showed greater species diversity in the canopy layer. The retained trees created patches of different species composition in the understory. The spatial gradient of shade and colonization opportunity provided by retained trees greatly affect the distribution of the colonized species, according to their shade tolerance and seed-dispersal ability, which resulted in the stand structure with a heterogeneous shrub-layer vegetation. Retention proved particularly important for the enhancement and long-term maintenance of structural and compositional complexity in L. kaempferi plantations.

Effects of extending rotation period on plant species diversity in Larix kaempferi plantations in central Japan

Nous avons compare la diversite en especes vegetales du sous bois entre des plantations de Larix kaempferi menees en rotations longues par rapport a des rotations classiques courtes ou des taillis abandonnes. La diversite et la richesse en especes vegetales ne different pas entre les plantations classiques et les plantations a longue rotation. Cependant, la diversite de la strate arboree, avec des strategies de dispersion des graines differentes, differe entre les plantations a longue duree par rapport aux plantations classiques mais est semblable aux taillis abandonnes. Les resultats indiquent en particulier que les plantations avec de longues rotations contiennent plus d'especes arborees avec une strategie de dissemination des graines par zoochorie ce qui suggere egalement que ce type de plantation longue soit favorable aux arbres avec ce type de dissemination. La longue periode apres la derniere intervention en foret dans les plantations a longue rotation semble donc jouer un role important dans la croissance, la reproduction et la dispersion des graines par zoochorie pour les arbres se regenerant naturellement. Par consequent, les plantations a longue rotation pourraient maintenir et restaurer la composition en especes vegetales par retablissement de la fonction ecologique.

Differences in plant species diversity in Larix kaempferi plantations of different ages in central Japan

To clarify the relationships among stand age and species diversity, richness, and composition, we studied the effects of stand age on plant species diversity in Larix kaempferi plantations in central Japan. We also identified which species group, classified by seed-dispersal type and life form, was most affected by stand age. Young plantations (about 15-year-old) had the highest species diversity and richness and included many species not found in older plantations (about 60-year-old). Forty-year-old plantations contained fewer species with animal-dispersed seeds than did younger and older plantations. In older stands, we found both more woody species and more species with animal-dispersed seeds. Although certain species traits (i.e. woody species and species with animal-dispersed seeds) were positively affected, extending the rotation age of plantations did not contribute to meaningfully increased species richness or diversity. These results show some of the contributions of long-rotation plantations to the maintenance of ecological processes and function.

Bark-stripping by Sika deer ( Cervus nippon) in Larix kaempferi plantations in central Japan

We studied bark-stripping by Sika deer ( Cervus nippon) in three types of Larix kaempferi plantations (old, not recently managed mid-aged, and mid-aged just after thinning) in central Japan. Most trees that had been stripped of bark were naturally regenerated, deciduous broad-leaved species, not planted L. kaempferi. Stands that had been recently thinned and consequently had relatively few naturally regenerated stems suffered the least bark-stripping. The species composition of naturally regenerated trees and the stem density of species that were frequently stripped did not differ between the old plantation and the mid-aged plantation that had not recently been managed. However, the proportion of stripped stems was higher in the mid-aged plantation than in the old plantation. This may have been because the average stem diameter of the species that were frequently stripped was smaller in the mid-aged plantation than in the old plantation, while the sizes of stems that were stripped did not differ. Therefore, stands that had many small stems of preferred species were more damaged.