• 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.

• Asian-Australasian Journal of Animal Sciences
• /
• v.12 no.5
• /
• pp.758-765
• /
• 1999

Comparative studies of the effects of rates and frequency of application of dairy slurry on herbage yield and stand persistence of alfalfa and various forage grasses have not previously been conducted. The results being reported here are part of a larger study having a primary objective of comparing the effectiveness of alfalfa (Medicago sativa L.), various grasses and alfalfa-grass mixtures for utilizing nutrients from applied dairy slurry. The objectives of this part of the study were to evaluate the effects of various rates and frequencies of application of slurry on herbage yield and stand persistence of orchardgrass (Dactylis glomerata L.), reed canarygrass (Phalaris arundinacea L.), and alfalfa-orchanrdgreass and alfalfa-reed canarygrass mixtures managed as a 4-cutting management system. A randomized complete block design with treatments in a split plot arrangement with four replicates was used. The main plots consisted of 9 fertility treatments: 7 slurry rate and time of application treatments, one inorganic fertilizer treatment, and an unfertilized control. The sub-plots consisted of the two grasses and two alfalfa-grass mixture mentioned above. Slurry was composed from stored solids scraped from the alleyways of a free-stall housing barn and water added to form a slurry having about 8% solids. Manure was pumped from a liquid spreader tank into 10.4 L garden water cans for manual application to the plots. Herbage yields within species were generally unaffected by various rates of application in the first production year. Herbage yields of grasses and alfalfa-grass mixtures the second year were generally not affected by frequency of application for the same rate of slurry applied. Slurry application resulted in greater herbage yield increases in grasses than alfalfa-grass mixtures in the 4-cutting management system. In general, herbage dry matter yields of grasses from the dairy slurry treatments equaled or exceeded yields from the inorganic fertilizer treatment. Stand ratings of grasses and alfalfa-grass mixtures were not changed by manure application rates. In this study, the highest rate of slurry ($967kg\;total\;N\;ha^{-1}$ in 1995 plus $2,014kg\;N\;ha^{-1}$ in 1996) was not detrimental to herbage yields or stand persistence of any of the species. It was concluded that applying dairy slurry to these cool-season grasses and alfalfa-grass mixtures managed in a 4-cutting system is an acceptable practice from the standpoint of herbage yield and satnd persistence and by doing so the utilization of inorganic fertilizers can be reduced.

• Journal of Korean Society of Forest Science
• /
• v.109 no.2
• /
• pp.202-210
• /
• 2020

This study investigated the optimal levels of stand density control considering the stability of Larix kaempferi stands. A stand density management diagram was developed from 259 sample plots. Based on these data, we determined an optimal level of the stand density control by identifying the relationship between the relative yield index (Ry) and height-to-diameter ratio. The estimated r-square (R²) of the stand density management diagram is 0.600. The analysis of the relationship between Ry and the slender tree incidence showed that when the stand density exceeded a certain threshold and the ratio of slender trees rapidly increased. The critical value of Ry was 0.63. The results of this study are expected to contribute to the establishment of stand management strategies that can reduce damage from natural causes, such as wind and snow, and to develop stand practice systems for the improved productivity of commercial forests.

• Journal of Korean Society of Forest Science
• /
• v.106 no.4
• /
• pp.457-464
• /
• 2017

This study has utilized the stand density management diagram to devise an efficient management standard for the stand density for Pinus densiflora that secures the health of the stands and predicted the harvest goals. The appropriate stand control level was estimated by modeling the relationship of the relative yield index (Ry) to the ratio of slender trees within the stand through an exponential function; the coefficient of determination ($R^2$) was found to be 0.424 according to the estimation. The ratio of slender trees within the stand showed a tendency of rapid increase at a certain relative yield index; with this relational function, the appropriate Ry value of 0.84 was obtained. By estimating the curve of the Ry value 0.84, which was the appropriate stand density management level, as well as the height of dominant trees in the central region of Korea, the production objective for each site index was set. Assuming that the final age by the site indices ranged from 10 to 16 for the P. densiflora in central region of Korea, the number of production was estimated to be between 426 to 1,311 trees per ha. It was predicted that the production of medium-diameter logs larger than 30 cm in diameter is possible for the target DBH at a site index of more than 16; small-diameter logs larger than 20 cm in diameter for site indices 12 and 14 enabled, and small-diameter logs of less than 20 cm for site index 10.

• Journal of Korean Society of Forest Science
• /
• v.101 no.4
• /
• pp.592-598
• /
• 2012

Forest stand yield and its changes along with 10 thinning scenarios were estimated using a forest stand yield model for six major tree species in Korea, such as Pinus densiflora in Gangwon province, Pinus densiflora in other regions, Pinus koraiensis, Larix leptolepis, Quercus acutissima Carruth, Quercus mongolica. The 10 thinning scenarios were generated based on a number of constraints and assumptions. For instance, it was assumed that thinning is implemented between 15 years and 40 years with 5 year period and its duration should be at least 10 years. Also, the overall removal rate from the thinning treatments was assumed to be not greater than 60%. Under the 10 scenarios, the overall stand yield volumes from thinning and final harvesting were estimated for each species and site index. The results showed that highest yield volumes were obtained for Pinus densiflora in Gangwon province, Pinus koraiensis and Quercus mongolica when 30% of basal areas were thinned at 20 and 40 years, while highest yield volumes were obtained for Pinus densiflora in other regions and Larix leptolepis when 20% of basal areas were thinned at 20, 30 and 40 years. Those two scenarios gave the same amount of highest yield volume for Quercus acutissima Carruth. Also the results indicated that thinning treatment is effective to increase overall stand yield volume and its effects are larger with a higher site index. The largest thinning effects were found in Pinus densiflora in Gangwon province (28%) and Larix leptolepis (25%), while limited in Pinus koraiensis (12%). The forest stand yield model, used in this research, could be an effective tool for estimating the stand dynamics with various thinning treatments, but it could be improved in a further research that validates its applicability in the field.

• Journal of Animal Science and Technology
• /
• v.63 no.4
• /
• pp.799-814
• /
• 2021

Information is lacking about the effect of date of a fall cut of alfalfa (Medicago sativa L.) on dry matter yield (DMY), forage nutritive value, and stands persistence. The objective of this study was to determine the effect of timing of a fall cut on DMY, forage nutritive value and stand persistence of three alfalfa varieties: low-lignin Hi-Gest 360, Roundup Ready Tonica, and conventional Gunner in Northeastern Kansas in the United States. The field study was carried out by splitting plot in randomized complete block design with four replications. The harvesting data of different maturity stages were collected in each year from 2015 to 2018. Three cuts were harvested based on the stage of maturity, and the last (fourth) cut was done on September 15, September 30, October 15, and October 30 of each year. The persistence of the alfalfa stands was determined each fall after the last cut, and each spring after the first cut, by counting the number of live plants in a randomly placed quadrat in each plot. Alfalfa cut on September 15 and September 30 had a higher stand persistence compared to alfalfa cut on October 15 and October 30. The DMY of the first cut in 2016 was significantly higher in roundup ready than the low-lignin alfalfa variety. In the second cut, DMY was significantly higher in conventional alfalfa than the roundup ready. There were no significant differences in DMY between alfalfa varieties in the rest of seasonal cuttings in 2016 and 2017 and annual total yield in both years. In general, low lignin alfalfa variety had higher crude protein and relative feed value and lower acid detergent fiber and neutral detergent fiber contents than those in roundup ready and conventional alfalfa varieties. On average, nutritive value of alfalfa was generally affected by last cutting dates in 2017. Based on 3-year data the last cutting of alfalfa in the fall could be done by September 30-October 15 without harmful effect on DMY.

• Journal of Korean Society of Forest Science
• /
• v.90 no.5
• /
• pp.650-662
• /
• 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 CROP SCIENCE
• /
• v.49 no.3
• /
• pp.184-187
• /
• 2004

In case of a semi-forcing culture for vegetable perilla, the following research results on the effect of black polyethylene mulching, the optimum sowing season, and the seedling stand improvement method were drawn. Soil temperature was higher and the emergence was faster in a black polyethylene mulching culture than in a non-mulching culture. However, the mature was late, the main stem were larger, and the seed yield, as well as the leaf yield, was greater in a mulching culture than in a non-mulching culture. Considering growth and chilling injury, the stable sowing season of vegetable perilla was judged to be the early in January. The covering materials for improvement of the seedling stand can be a non-woven fabric and hyaline polyethylene. However, the non-woven fabric seemed to be quite suitable in view of the stability and convenience of control after the emergence of perilla.

• Journal of Korean Society of Forest Science
• /
• v.99 no.1
• /
• pp.9-15
• /
• 2010

This study was conducted to develop a stand growth model and a stand yield table for Eucalyptus pellita and Acacia mangium plantations in Kalimantan, Indonesia. To develop a stand growth model, Weibull robability density function, a diameter class model, was applied in this study. In the development of stand growth model by site index and stand age, a hierarchy is generally required - estimation, recovery and prediction of the diameter class model. A number of grow equations were also involved in each process to estimate diameter, height, basal area, minimum or maximum diameter. To examine whether the grow equations are adequate for Eucalyptus pellita or Acacia mangium plantations, a fitness index was analyzed for each equation. The results showed that fitness indices were ranged from 65 to 89% for Eucalyptus pellita plantations and from 72 to 95% for Acacia mangium plantations. As being highly adequate for the plantations, a stand yield table was developed based on the resulted growth model, and applied to estimate the stand growth with midium site index for 10-year period. The highest annual stand growth of Eucalyptus pellita plantations was estimated to be 21.25 $m^3$/ha, while that of Acacia mangium plantations was 27.5 $m^3$/ha. In terms of annual stand growth, Acacia mangium plantations appeared to be more beneficial than Eucalyptus pellita plantations. Also, to estimate commercial timber volume available from the plantations, an assumption that a log would be cut by 2.7 m in length and the rest of the log would be cut by 1.5m was involved. The commercial timber volume available from Eucalyptus pellita plantations was 68.0 $m^3$/ha, 33% from the total stand volume, 203.2 $m^3$/ha. Also 96.7 $m^3$/ha of commercial timbers were available from Acacia mangium plantations, which was 42% from the 232.9 $m^3$/ha in total. Presenting a good information about the stand growth in Eucalyptus pellita and Acacia mangium plantations, this study might be useful for whom proceeds or considers an abroad plantation for merchantable timber production or carbon credit in tropical regions.

• Asian-Australasian Journal of Animal Sciences
• /
• v.12 no.5
• /
• pp.766-771
• /
• 1999

The first paper of this series compared the effects of rates and frequencies of application of dairy slurry on herbage yields and stand persistence of orchardgrass (Dactylis glomerata L.), reed canarygrass (Phalaris arundinacea L.), and alfalfa (Medicago sativa L.)-grass mixtures managed as a 4-cutting system. This paper compares the effects of rates and frequencies of application of dairy slurry on herbage yield and stand persistence of alfalfa, orchardgrass, tall fescue (Festuca arundinacea Schreb.), and alfalfa-orchardgrass mixture managed as a 5-cutting system. The results presented here are part of a larger study having a primary objective of comparing alfalfa, various grasses, and alfalfa-grass mixtures for utilizing nutrients from dairy slurry applied to established stands. A randomized complete block design with treatments in a split plot arrangement with four replicates was used. The main plots consisted of 9 fertility treatments: 7 slurry rate and frequency of application treatments, one inorganic fertilizer treatment, and an unfertilized control. The sub-plots were the forage species. Manure used for the study was composed from stored solids scraped from the alleyways of a free-stall dairy barn. Water was added to from a slurry having about 8 % solids. Slurry was pumped from the liquid spreader tank into 10.4 L garden watering cans for manual application to the plots. Herbage yields of alfalfa, tall fescue, and alfalfa-orchardgrass were generally not affected by slurry application rates and were not significantly different from the inorganic fertilizer treatment. Tall fescue significantly outyielded all other forage species at all manure and the inorganic fertilizer treatments in the second year when rainfall during the growing season was unusually high. Grasses generally had a greater response to manure applications than alfalfa and alfalfa-orchardgrass. Increasing rates of manure did not increase herbage yields of alfalfa and alfalfa-orchardgrass. Herbage yields within each species were not affected by frequency of application of the same total rate. Stand ratings of alfalfa, orcahrdgrass and alfalfa-orchardgrass were significantly lower for the very high manure application rate compared to the control treatment. Based upon the results of this study, multiple annual applications of slurry manure can be made onto these species at rates up to $1,700kg\;total\;N\;ha^{-1}\;yr^{-1}$ without detrimental effects on herbage yield and stand persistence.