• Title/Summary/Keyword: Forest stand

Search Result 760, Processing Time 0.033 seconds

Application of Finite Mixture to Characterise Degraded Gmelina arborea Roxb Plantation in Omo Forest Reserve, Nigeria

  • Ogana, Friday Nwabueze
    • Journal of Forest and Environmental Science
    • /
    • v.34 no.6
    • /
    • pp.451-456
    • /
    • 2018
  • The use of single component distribution to describe the irregular stand structure of degraded forest often lead to bias. Such biasness can be overcome by the application of finite mixture distribution. Therefore, in this study, finite mixture distribution was used to characterise the irregular stand structure of the Gmelina arborea plantation in Omo forest reserve. Thirty plots, ten each from the three stands established in 1984, 1990 and 2005 were used. The data were pooled per stand and fitted. Four finite mixture distributions including normal mixture, lognormal mixture, gamma mixture and Weibull mixture were considered. The method of maximum likelihood was used to fit the finite mixture distributions to the data. Model assessment was based on negative loglikelihood value ($-{\Lambda}{\Lambda}$), Akaike information criterion (AIC), Bayesian information criterion (BIC) and root mean square error (RMSE). The results showed that the mixture distributions provide accurate and precise characterisation of the irregular diameter distribution of the degraded Gmelina arborea stands. The $-{\Lambda}{\Lambda}$, AIC, BIC and RMSE values ranged from -715.233 to -348.375, 703.926 to 1433.588, 718.598 to 1451.334 and 3.003 to 7.492, respectively. Their performances were relatively the same. This approach can be used to describe other irregular forest stand structures, especially the multi-species forest.

Development of Stand Yield Table Based on Current Growth Characteristics of Chamaecyparis obtusa Stands (현실임분 생장특성에 의한 편백 임분수확표 개발)

  • Jung, Su Young;Lee, Kwang Soo;Lee, Ho Sang;Ji Bae, Eun;Park, Jun Hyung;Ko, Chi-Ung
    • Journal of Korean Society of Forest Science
    • /
    • v.109 no.4
    • /
    • pp.477-483
    • /
    • 2020
  • We constructed a stand yield table for Chamaecyparis obtusa based on data from an actual forest. The previous stand yield table had a number of disadvantages because it was based on actual forest information. In the present study we used data from more than 200 sampling plots in a stand of Chamaecyparis obtusa. The analysis included theestimation, recovery and prediction of the distribution of values for diameter at breast height (DBH), and the result is a valuable process for the preparation ofstand yield tables. The DBH distribution model uses a Weibull function, and the site index (base age: 30 years), the standard for assessing forest productivity, was derived using the Chapman-Richards formula. Several estimation formulas for the preparation of the stand yield table were considered for the fitness index, and the optimal formula was chosen. The analysis shows that the site index is in the range of 10 to 18 in the Chamaecyparis obtusa stand. The estimated stand volume of each sample plot was found to have an accuracy of 62%. According to the residuals analysis, the stands showed even distribution around zero, which indicates that the results are useful in the field. Comparing the table constructed in this study to the existing stand yield table, we found that our table yielded comparatively higher values for growth. This is probably because the existing analysis data used a small amount of research data that did not properly reflect. We hope that the stand yield table of Chamaecyparis obtusa, a representative species of southern regions, will be widely used for forest management. As these forests stabilize and growth progresses, we plan to construct an additional yield table applicable to the production of developed stands.

Preliminary Study on Naturalness of Korean Fir (Abies holophylla) Stand in Mt. Sorak (설악산 전나무 고목림의 자연성 판단을 위한 기초연구)

  • 윤영일
    • Korean Journal of Environmental Biology
    • /
    • v.20 no.4
    • /
    • pp.287-293
    • /
    • 2002
  • Natural forest stand plays a very important role to understand the forest ecosystem in Korea, in which there is no ancient forests aye left. Several old growth Korean fir stands were studied to determine their naturalness. Internationally accept-ed criteria for virgin or natural forests were used and the changes in several stages by stand dynamics were applied. Although the areas survey is limited in size, it was discovered that they clearly represent certain characteristics of naturalness. This study and collected data will hopefully be the starting point for the further studies for naturalness of forest in Korea in the future.

Estimation of Stand Yield and Carbon Stock for Robinia pseudoacacia Stands in Korea (아까시나무 임분의 임목수확량 및 탄소저장량 추정)

  • Son, Yeong Mo;Kim, So Won;Lee, Sun Jeoung;Kim, Jeong Soo
    • Journal of Korean Society of Forest Science
    • /
    • v.103 no.2
    • /
    • pp.264-269
    • /
    • 2014
  • The aim of this study was to determine the current distribution area of Robinia pseudoacacia habitat and to estimate its stand yield as well as its carbon stocks. In order to do so, the area of R. pseudoacacia distribution is obtained based on the large-scaled forest type map (1:5,000). Also, Weibull diameter distribution model is used to predict the yield of R. pseudoacacia stands. In addition, carbon emission factor is applied to calculate carbon stocks and removals. To obtain the stand yield of R. pseudoacacia, we developed estimation equation considering growth factors of the stand, e.g. mean diameter, the basal area, maximum and minimun diameter and etc. and tested it to ensure accuracy. Consequently, estimation equation derived from all growth factors have shown significance that could also be used for analysis. Site index was also established to determine the productivity of the forestland that later turned out to be ranging from 16 to 22. Based on these results, stand yield tables were drawn up. R. pseudoacacia is widely distributed in inland areas of Gyeongsang, Chungcheong and Gyeonggi provinces which covers total area of 26,770 ha. And when it is converted into carbon stocks, it amounts to 2,517,598tC with annual carbon uptake of 3.76tC/ha which is comparable to Querqus species that is known to storer large amounts of carbon. Therefore, R. pseudoacacia is also expected to serve as a viable carbon pool that would contribute to the mitigation of climate change. Furthermore, stand yield tables, an outcome of this survey would assist not only in proper management but also in sustainable management policy of R. pseudoacacia.

Estimating Dense Forest Canopy Structure Using Airborne Laser Scanner Data

  • Park J. H.;Jang K. C.;Ma J. L.;Lee K. S.
    • Proceedings of the KSRS Conference
    • /
    • 2004.10a
    • /
    • pp.638-641
    • /
    • 2004
  • Returned laser pulse has certain relationship with vegetation canopy structure (canopy closure, height, LAI, biomass). This study attempts to analyze the characteristics of airborne laser scanner data over very dense forest canopy. Discrete pulse laser scanner data were obtained on April 25, 2004 along with digital aerial color imagery. Using forest stand maps, 14 sample stands of 7 species groups were selected and the elevations from the first and last laser return were compared. From the preliminary analysis, we found that the difference between the first and last return was higher with deciduous forest stand than in coniferous stand. Although difference between the first and the last laser returns often corresponds to tree height, it would not be the case for the forest site having very dense canopy structure.

  • PDF

Studies on Biomass for Young Abies koreana Wilson

  • Lee, Do-Hyung;Yoon, Jun-Hyuck;Woo, Kwan-Soo
    • Journal of Korean Society of Forest Science
    • /
    • v.96 no.2
    • /
    • pp.138-144
    • /
    • 2007
  • This study was undertaken to compare the biomass of Abies koreana growing at two sites. A $10{\times}10m$ plot was established in each site of a natural stand in Mt. Jiri and a plantation in Gyeongsan nursery. Five trees of A. koreana were randomly selected in each site. The following traits were investigated from each tree : height, basal diameter, age, weight of stem, branches, and needles as above-ground traits and weight of total roots, horizontal roots, and vertical roots as below-ground traits. In Gyeongsan nursery, age of sample trees was negatively correlated with both height and weight of total stem, while height was highly correlated with weight of horizontal roots. There was high correlation between the basal diameter and weight of total stem, and between the basal diameter and weight of roots. In Mt. Jiri stand, most of the above-ground traits except age were significantly correlated with the below-ground traits. The linear regression equation between the cross section area of base (X) and the weight of total stem (Y) in Gyeongsan nursery was Y=12.66X-12.92, and correlation was significant ($R^2=0.89$). The linear regression equation between the cross section area of base(X) and the weight of total branches (Y) in Mt. Jiri stand was Y=25.51X+6.00, and correlation was highly significant ($R^2=1.0$).

Distribution of Carabid Beetles(Coleoptera: Carabidae) in different forests of Central Kangwon-do (강원 중부지역 산림내의 딱정벌레과(科) 분포에 관한 연구)

  • Chang, Suk-Jun;Kim, Jong-Kuk
    • Journal of Forest and Environmental Science
    • /
    • v.16 no.1
    • /
    • pp.42-49
    • /
    • 2000
  • This study deals with the structure of Carabid beetle community surveyed in different stands. Species richness and abundance of Carabid beetles were 1,162 individuals, 23 species, 10 genera in the Pinus densiflora stand, 418 individuals, 23 species, 11 genera in the Pinus koraiensis stand, 782 individuals, 25 species, 11 genera in the Larix leptolepis stand, 1,383 individuals 25 species, 12 genera in the Quercus variabilis stand. Dominant species were Synuchus cycloderus(19.8%), Synuchus nitidus(16.6%), Pterostichus pertirax(16.2%) in the Pinus densiflora stand. Pterostichus sp.1(27.9%), Synuchus nitidus(24.4%), Synuchus cycloderus(10.2%) in the Pinus koraiensis stand, Synuchus sp.1(40.0%), Synuchus nitidus(9.3), Pterostichus sp.1(7.4%) in the Larix leptoepis stand. Pterostichus sp.2(17.4%), Synuchus cycloderus(14.4%). Pterostichus pertirax(14.1%) in the Quercus variabili stand. Shannon species diversity index(H') in the Pinus densiflora, Pinus koraiensis, Larix leptolepis and Quercus variabilis stand were 2.11, 2.25, 2.23 and 2.32 respectively and Evenness index(J') were 0.64, 0.72, 0.69 and 0.72, respectively. Community similarity index showed the lowest value (0.66) between Quercus variabilis stand and Pinus koraiensis stand and the highest value (0.83) between Pinus densiflora stand and Larix leptolepis stand.

  • PDF

Studies on the Estimation of Stand Volume Increment in the Jack Pine (Pinus banksiana Lamb.) in Artificial Forest (방크스소나무 인공림(人工林) 임분(林分)의 재적생장(材積生長) 추정(推定)에 관(關)한 연구(硏究))

  • Lee, Jong-Lak
    • Journal of Korean Society of Forest Science
    • /
    • v.89 no.3
    • /
    • pp.414-421
    • /
    • 2000
  • This study was carried out for the artificial forest stand of 23 years old jack pine(Pinus banksiana Lamb.) in Soheul-myun, Pochun-kun, Kyunggi province of Korea. The objectives of this study were to investigate the stand volume increment and the rate of stand volume, and were to investigate present stand volume to determine annual cutting volume for keeping stand volume to an ideal level for investigated jack pine stand. For a reasonable calculation of stand volume increment, diameter of breast height(DBH), tree height, bark width, and core length for the last 10 years for respective sampling plots were measured. By using these measurements annual diameter increment in DBH class, stand volume increment of 95% confidence interval and tree height curve equation were calculated. The tree height value was derived from the tree height curve equation. Calculation of tree volume by using the tree volume table was made by conferring the tree height value. The summarized results for investigated jack pine trees were having 7.7% annual stand volume increment with 6.1% estimated error. The total stand volume per ha was $79.58m^3$, accordingly the annual stand volume increment was $6.13m^3$ per ha, and the 95% confidence intervals range from 5.77 to $6.51m^3$.

  • PDF

Stand Structure and Growth Characteristics at Different Elevations of the Korean Pine(Pinus koraiensis) Natural Forest on Mt. Seorak (설악산 잣나무(Pinus koraiensis) 천연림의 해발고별 임분구조 및 생장특성)

  • Kim, Hyun-Seop;Bae, Sang-Won;Jang, Seok-Chang;Jeong, Jun-Mo
    • Journal of Forest and Environmental Science
    • /
    • v.27 no.3
    • /
    • pp.157-167
    • /
    • 2011
  • This study was conducted to analyze the stand structure and growth characteristics along different elevations of Pinus koraiensis natural forests located at mean elevation 1,300 m (site1), 900 m (site2) and 600 m (site3) on Mt. Seorak. Mean DBH and height of P. koraiensis were 25.4 cm and 12.3 m in site1, while that of site2 and 3 were over 40 cm and 20 m, respectively. For this reason, there was 5 times difference of single tree volume between site1 and other sites(p<0.05). Mean ringwidth increment of P. koraiensis was 1.1 mm/yr in site1, 1.5 mm/yr in site2 and 2.6 mm/yr in site3. However, recent growth of ringwidth has increased by 8.6% in site1, whereas site2 and 3 have fallen by approximately 50% over the last 10 years. These results signify that the growth and distribution of natural P. koraiensis are effected by different climatic environment along elevations.