• Journal of Korean Society of Forest Science
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• v.105 no.3
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• pp.330-335
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• 2016

This study was conducted to derive merchantable volume ratio for 5 major species such as Pinus Densiflora (Central Region). The data used for this study was from at least more than 1,300 trees of research data throughout the country. the study applied two estimation equations, which were the estimation equation for wood volume ratio representing total wood volume to total tree stem volume and the estimation equation for merchantability representing ratio of merchantable volume to total wood volume. The merchantable volume ratio was derived by multiplying those two estimation equations. In order to gain wood volume ratio(W) from DBH, $W=\frac{a_1}{1+a_2/D}+\frac{b_1}{1+b_2/D}$ model was used. Fitness index of it was more than 99% by species, and other test statistics also indicated the suitability of this equation enough. Merchantability (M) for wood volume applied $M=e^{a_1\(\frac{d}{D}\)^{a_2}}-(b_0+b_1D+b_2D^2+b_3D^3)$ model and fitness index was more than 96% by species. Merchantable volume ratio was assessed using those two estimation equations by each 5 species, and constructed a merchantable volume ratio table. In result, merchuntable volume ratio was little difference between stand types, but there was slightly different with the existing standard such as conifers of 85% and non-conifers of 70%.

• Journal of Forest and Environmental Science
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• v.40 no.1
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• pp.35-42
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• 2024

The Japanese larch (Larix kaempferi [Lamb.] Carriere) is a major timber species in Korea. However, studies on bucking rates and merchantable logs of this species are insufficient in South Korea. To bridge these gaps, in this study, the bucking rate of Japanese larch (Larix kaempferi [Lamb.] Carriere) was computed and the number of long logs and merchantable log volumes were analyzed. Sample trees were bucked according to the log grade for trading, and collected from a forest field in Gangwon Province. The bucking rate of all Japanese larch logs was >89%. The highly profitable 2-4 logs of 3.6 m length from trees with ≤30 cm diameter at breast height (DBH) and 5-6 logs with ≥34 cm DBH were produced. The bucking rate of long logs was >84%; thus, Japanese larch was found to be suitable for the supply of high-grade timber. Additionally, to follow reasonable wood supply plans, merchantable volume tables were offered based on 3.6 m-long number of logs and small-end diameter classes. Understanding the proportion of merchantable log volumes, bucking rates, and the number of long and short logs has large-scale applications in practical forestry.

• Journal of Korean Society of Forest Science
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• v.96 no.3
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• pp.362-368
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• 2007

This study was conducted to estimate merchantable volume and yield per diameter (DBH) class of Pinus koraiensis and Larix kaempferi. Stem volume of trees in each diameter class was calculated using the existing equations for taper and height curve. Saw logs and pulpwood volume were then estimated from the stem volume in each diameter class. The final step was to estimate merchantable volume and yield from saw logs, assuming saw logs were used for lumber (boards or dimension products) production only. The results showed that the stem volume of Larix kaempferi was 23~38% higher than that of Pinus koraiensis at the same diameter classes. Both species were able to produce saw logs from the diameter class of 18 cm. Saw logs and pulpwood yield for both species rapidly increased due to the size limitation on small end diameter. This yield reached a maximum of 90% and 88% at 26 cm and 38cm diameter class, respectively, for Pinus koraiensis and Larix kaempferi. Lumber yield estimated for board products ranged from 23% to 56%. In the case of dimension products, Lumber yield became significantly smaller as saw logs were used for larger dimension products. These results can be used for calculating merchantable volume and economic value of trees, as well as determining final lumber products.

• Journal of Korean Society of Forest Science
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• v.106 no.4
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• pp.480-486
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• 2017

This study was conducted to develop the merchantable stem volume models to predict the volume up to upper diameter or upper height out of the total stem volume, targeting on Pinus densiflora, Pinus koraiensis, and Larix kaempferi in South Korea. The 131 stemmed sample trees for stem analysis were used as the data for developing the models. The six kinds of merchantable volume equations including merchantable volume ratio form, ratio form, and exponential ratio form were examined to develop the best models. The two models were finally selected as the best models to predict the merchantable volume: $V_d=V_t\{{\exp}[{\alpha}_1(d^{{\alpha}_2}/D^{{\alpha}_3})]\}$ for upper diameter and $V_h=V_t\{1+{\beta}_1(P^{{\beta}_2}/H^{{\beta}_3})\}$ for upper height. By rearranging the best model equations, implicit taper functions were derived, and the estimation was performed for the upper height by upper diameter and upper diameter by upper height. Because of not only the high accuracy but also the convenience, the models developed in this study were considered to be easily applicable in the field of forestry.

• Journal of Korean Society of Forest Science
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• v.74 no.1
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• pp.82-87
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• 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 Forest and Environmental Science
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• v.33 no.3
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• pp.233-238
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• 2017

This study was carried out to figure out the number of logs for sawtimber by DBH and height class and to compare merchantable volume ratio by categorizing into sawtimber, lagging board and pulpwood, and others for Pinus densiflora, Pinus koraiensis, and Larix kaempferi. Logs for sawtimber were hardly produced in small DBH class of three species, but produced evidently from medium DBH class. In large DBH class, the number of logs for sawtimber were noticeably different among species: 4.3 logs for L. kaempferi, 2.6 logs for P. densiflora, and 1.0 logs for P. koraiensis on average. Similarly, merchantable volume ratio for sawtimber were largely different among species in large DBH class with higher than 15 m: 82% logs for L. kaempferi, 60% logs for P. densiflora, and 44% logs for P. koraiensis. When compared to the upper diameter and upper height by species with regard to the last log of a tree produced for sawtimber, upper diameter was smallest with 14.1 cm and upper height was highest with 12.2 m in L. kaempferi. Overall, L. kaempferi was considered as the more commercial species for sawtimber production than P. densiflora and P. koraiensis.

• Journal of Korean Society of Forest Science
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• v.90 no.3
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• pp.331-337
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• 2001

This study was performed to develope stem analysis program(Stemwin1.0) which can be used in PC with MS-Windows operating system. Stemwin1.0 uses width of annual tree ring measured with 1/100mm unit, and calculate increments of several growth factors such as DBH, height and volume with various methods. Mean DBH can be calculated by arithmetic and quadratic mean methods. Height can be estimated by parallel line, line extending and height curve methods. Volume can be estimated by Huber, Smalian, and Spline functions. Not only Total growth, Mean Annual Increment(MAI) and Current Annual Increment(CAI) of growth factors, but also merchantable volume and height, form factor, growth rate, and merchantable volume rate are automatically calculated. Stemwin1.0 can also output accurate stem taper curve with various scale, and prepare stem taper data(diameter at different disk heights) for statistical analysis for deriving stem taper model. Stemwin1.0 can export output data and graph to Excel for more compatible use of it.

• Journal of Korean Society of Forest Science
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• v.102 no.4
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• pp.484-490
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• 2013

This study was conducted to develop a simulation model for estimating the amount of such products as round wood, dimension lumber and the residual wood biomass produced by processing the individual trees of Larix kaempferi. In the model, the stem volume is assessed using the taper equations of the species to estimate the stem forms. Then, the model simulates the conversion processes of logs to round wood or lumber and assesses the maximum amount of the wood products by the lumber dimensions or round wood size. Also the model provides information on the amount of residuals for kerf and slabs produced on the conversion processes for sawn timber or round wood. According to the results of an application of the model to a L. kaempferi process, the trees greater than 12 cm of DBH can be converted to logs for lumber or round wood production. For the trees, of which DBH is available for log conversion, the maximum amount of final products by dimensions were analyzed. In this analysis, production of the bigger dimension lumber was assumed to be preferred to that of the smaller or round wood. This model can be used for assesment of forest economic value through estimation of merchantable volume for the trees, and assessment of mill residues which has the potential to provide significant amount of feedstock for bioenergy production as well.

• Journal of Korean Society of Forest Science
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• v.107 no.2
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• pp.184-192
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• 2018

In this study was implemented to develop tree stem weight prediction equation of Larix kaempferi in central region by selecting a standard site, taking into account of diameter and position of the local trees. Fifty five sample trees were selected in total. By utilizing actual data of the sample trees, 11 models were compared and analyzed in order to estimate four different kinds of weights which include fresh weight, ovendry outside bark weight, ovendry inside bark weight and merchantable weight. As to estimate its weight, the study has classified its model according to three parameters: DBH, DBH and height, and volume. The optimal model was chosen by comparing the performance of model using the fit index and standard error of estimate and residual distribution. As a result, the formula utilizing DBH (Variable 1) is $W=a+bD+cD^2$ (3) and its fit index was 90~92%. The formula for DBH and height (Variable 2) is $W=aD^bH^C$ (8) and its fit index was 97~98%. In summation, Variable 2 model showed higher fitness than Variable 1 model. Moreover, fit index of formula for total volume and merchantable volume (W=aV) showed high rate of 98~99%, as well as resulting 7.7-17.5 with SEE and 8.0-10.0 with CV(%) which lead to predominately high fitness in conclusion. This study is expected to provide information on weights for single trees and furthermore, to be used as a basic study for weight of stand unit and biomass estimation equations.

• Journal of Forest and Environmental Science
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• v.24 no.1
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• pp.1-14
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• 2008

Clearcutting has been the dominant harvesting method in British Columbia (representing 95% of the total area harvested annually). However forest managers are increasingly recommending the use of alternative silvicultural systems and harvest methods, including various types of partial cutting, to meet ecological and social objectives. In this study we compared harvesting productivity and harvesting costs between treatments through detailed and shift level time studies in 300-350 year-old Interior Cedar-Hemlock stands in British Columbia, Canada. Recommendations for improving operational planning/layout and the implementation of clearcut and partial cutting silvicultural systems were made. Harvesting costs varied in the ground-based clearcut treatments from $10.95/$m^3$ - $15.96/$m^3$ and $16.09/$m^3$ - $16.93/$m^3$ in the group selection treatments. The ground-based group retention treatment had a cost of $13.39/$m^3$, while the cable clearcut had a cost of $15.70/$m^3$. An understanding of the traditional and alternative wood products that could be derived from the harvested timber was imperative to increasing the amount of merchantable volume and reducing the corresponding harvesting costs. Stand damage was greatest in the group selection treatments; however, mechanized felling showed an increase in stand damage over manual felling while grapple skidding showed a decrease in skidding damage compared to line skidding.