Browsing by Author "Kara F."

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A Gingrich-style stocking chart for longleaf pine (Pinus palustris Mill.) forests
(2018-05-28) Kara F.; Loewenstein E.F.; Lhotka J.M.; Kush J.S.
Because of the dramatic decline in longleaf pine (Pinus palustris Mill.) acreage, concern about restoration and management of these ecosystems has increased in recent years and created a need for effective silvicultural management tools. Stocking charts are useful quantitative tools to allocate tree area to meet specific silvicultural objectives including restoration; however, there has not been one created specifically for longleaf pine forests. Because successful management of longleaf pine is often associated with density management at or near the onset of full site occupancy, which is readily determined on a stocking chart, the development of the chart for the species was needed. We developed a Gingrich-style stocking chart for longleaf pine forests using published approaches and models from the literature. Average maximum density (A-line stocking) was determined using forest inventory data whereas onset of full site occupancy (B-line stocking) was derived from an existing open-growth crown width equation. Reduced major axis regression was used to determine size-density relationships because it gives less biased and more efficient estimates than ordinary least squares regression. Previous studies, physiological data, and longleaf pine silvical traits all support the size-density characteristics depicted on this stocking chart. We found that percent stocking was better than basal area as a predictor of tree growth, although the difference between the two measures was not significant in understocked stands. The difference between percent stocking and stand density index as a predictor of tree growth was not statistically significant. With the stocking chart presented in this article, tree area relationships can be effectively and easily used to achieve specific silvicultural objectives.
A silvicultural management tool for the Oriental beech (Fagus orientalis Lipsky) forests
(2018-05-19) Kara F.; Kara, F
Stand density management tools help forest managers and landowners to more effectively allocate growing space so that specific silvicultural objectives can be met. Due to the economic importance of Oriental beech (Fagus orientalis Lipsky) forests in Turkey, a stand density management tool was developed for this species to optimize regeneration success rate and tree growth. For the development of this tool, named stand density management diagram (SDMD), we utilized forest inventory data from the Kastamonu Regional Forest Directorate in Turkey. Previously published forest management approaches and models were employed during the development of the tool. The SDMD illustrates the relation among four forest indexes: the basal area per hectare, number of trees per hectare, forest stand volume per hectare, and quadratic mean diameter of the beech stands. The stand stocking percent (SSP) can be determined based upon any two of these four measurements. The results suggest that SSP is a better predictor of tree growth than BA in Oriental beech forests. The newly developed SDMD allows for a more effective use of the growing space to achieve specific silvicultural objectives including tree regeneration, timber production, thinning planning, and wildlife protection in Oriental beech forests.
A silvicultural management tool for the Oriental beech (Fagus orientalis Lipsky) forests
(2018-05-19) Kara F.
Stand density management tools help forest managers and landowners to more effectively allocate growing space so that specific silvicultural objectives can be met. Due to the economic importance of Oriental beech (Fagus orientalis Lipsky) forests in Turkey, a stand density management tool was developed for this species to optimize regeneration success rate and tree growth. For the development of this tool, named stand density management diagram (SDMD), we utilized forest inventory data from the Kastamonu Regional Forest Directorate in Turkey. Previously published forest management approaches and models were employed during the development of the tool. The SDMD illustrates the relation among four forest indexes: the basal area per hectare, number of trees per hectare, forest stand volume per hectare, and quadratic mean diameter of the beech stands. The stand stocking percent (SSP) can be determined based upon any two of these four measurements. The results suggest that SSP is a better predictor of tree growth than BA in Oriental beech forests. The newly developed SDMD allows for a more effective use of the growing space to achieve specific silvicultural objectives including tree regeneration, timber production, thinning planning, and wildlife protection in Oriental beech forests.
Changes in stream morphology protected by best management practices under effects of upstream disturbances
(2019-08-01) Cavus I.; Kalin L.; Kara F.
Stream channels are usually more stable in forested watersheds. However, intensive land disturbances in forested watersheds may disrupt the balance between flow and sediment supply, and result in variations in stream morphology even in the presence of well-designed best management practices (BMPs). This study evaluated the impacts of upstream land disturbances on downstream stream morphology where streamside management zones (SMZs) were present in two small adjacent watersheds in Auburn, Alabama, USA. Field surveys including the measurements of channel cross sections at bankfull stage were conducted at 12 survey sites over an 18-month period. Both in-stream sediment deposition and erosion were observed downstream of the disturbed areas in the study watersheds. As a result, channel cross sections exhibited very dynamic patterns changing frequently over short time periods. Overall, the dominant process was in-stream deposition in both watersheds due to large amount of sediment delivered from upstream-disturbed areas. In spite of the dynamic patterns of the channel cross sections in response to upstream disturbances, the commonly used parameters of Rosgen stream classification remained stable, suggesting that the upstream disturbances did not lead to changes in stream classification. In general, bank erosion was not observed. Therefore, it is likely that SMZs in each watershed were sufficient to stabilize streambanks by hindering in-stream bank erosion. Moreover, the poorly designed BMPs such as silt fences and straw bales near the disturbed area seemed insufficient to balance the variations in sediment supply under the impacts of upstream disturbances. This study emphasized that proper installation and continuous monitoring of BMPs should play a critical role on watershed management. It also indicated that watershed management should be handled using a holistic approach with well-distributed BMP applications within the entire watershed.
CLIMATE AND SILVICULTURAL IMPLICATIONS IN MODIFYING STAND COMPOSITION IN MIXED FIR-PINE STANDS
(2020-07-03) Kara F.; Lhotka J.M.
A growing concern exists over the decreasing proportion of Scots pine (Pinus sylvestris L.) trees in mixed Trojan fir (Abies nordmanniana subsp. equi-trojani [Asch. & Sint. Ex Boiss] Coode & Cullen)-Scots pine forests in northern Turkey. Given the changes in mean annual temperature and annual precipitation for the last 40 years in the region, understanding of the sensitivity of Trojan fir and Scots pine trees to changing climate seems to be critical so that better management strategies can be developed against the potential climate extremes of the future in the region. Moreover, our knowledge on the influence of current silvicultural methods on seedling density and growth in these forests is limited. Therefore, in this study, the growth response (i.e., radial growth) of Trojan fir and Scots pine trees to the changing climate were examined. In addition, the influence of current silvicultural practices on seedling growth and density in these forests was also monitored. Trojan fir appeared more sensitive to the climatic variables (i.e., temperature and precipitation) than Scots pine in the region. It was also found that the current silvicultural practices might favor Trojan fir over Scots pine in these forests. Natural dynamics and current silvicultural implications would benefit Trojan fir, however, given the species’ potential sensitivity to the changing climate, current silvicultural approaches can be modified to favor Scots pine, and to increase the resilience of these forests against climate extremes expected in the region’s future.
Climate-Growth Relationships in Managed and Unmanaged Kazdağı Fir Forests
(2022-01-01) Kara F.
Climate change can affect tree growth, stand productivity, and tree mortality. The sensitivity of tree species to the changing climate may vary in managed and unmanaged forests. Thus, the main objective of this study was to examine whether the effects of climate vary in managed and unmanaged Kazdağı fir (Abies nordmanniana subsp. equi-trojani) forests in northern Turkey. Individual tree-ring chronologies from the managed and unmanaged forests of the species were used. Results indicated significant effects of climate (i.e., the standardized precipitation-evapotranspiration index (SPEI)), and forest type (i.e., managed and unmanaged) on radial growth of Kazdağı fir trees (p < .05). Trees in the unmanaged forest exhibited a lower radial growth rate and a higher sensitivity to climatic conditions compared to the managed forest. This can be associated with the reduced tree density following silvicultural treatments, which result in increased resource availability to the remaining trees in the managed forest. Initial findings would create a basis for future decisions that aim to enhance the resistance of Kazdağı fir forests against the future climate extremes of the region. Long-term monitoring is needed to observe the effects of forest type on the response of Kazdağı fir trees to the climate over time.
Climate-Growth Relationships in Managed and Unmanaged Kazdağı Fir Forests
(2022-01-01) Kara F.; Kara, F
Climate change can affect tree growth, stand productivity, and tree mortality. The sensitivity of tree species to the changing climate may vary in managed and unmanaged forests. Thus, the main objective of this study was to examine whether the effects of climate vary in managed and unmanaged Kazdağı fir (Abies nordmanniana subsp. equi-trojani) forests in northern Turkey. Individual tree-ring chronologies from the managed and unmanaged forests of the species were used. Results indicated significant effects of climate (i.e., the standardized precipitation-evapotranspiration index (SPEI)), and forest type (i.e., managed and unmanaged) on radial growth of Kazdağı fir trees (p < .05). Trees in the unmanaged forest exhibited a lower radial growth rate and a higher sensitivity to climatic conditions compared to the managed forest. This can be associated with the reduced tree density following silvicultural treatments, which result in increased resource availability to the remaining trees in the managed forest. Initial findings would create a basis for future decisions that aim to enhance the resistance of Kazdağı fir forests against the future climate extremes of the region. Long-term monitoring is needed to observe the effects of forest type on the response of Kazdağı fir trees to the climate over time.
Comparison of unmanaged and managed trojan fir–scots pine forests for structural complexity
(2020-01-01) Kara F.; Lhotka J.M.
Unmanaged forests may exhibit a higher degree of biodiversity compared to managed forests. We examined and compared the stand structure, density, and volume of deadwood components of managed and unmanaged mixed forests of Trojan fir (Abies nordmanniana subsp. equi-trojani [Asch. & Sint. ex Boiss] Coode & Cullen)–Scots pine (Pinus sylvestris L.) in northern Turkey. The single-tree selection method has been employed in the managed forests. Density of large live trees ha–1, density of standing deadwood (SDW) ha–1, and volume of lying deadwood (LDW) (m3 ha–1) were calculated for both treatments (i.e. managed or unmanaged). Results showed that unmanaged forests had significantly higher density of large live trees and SDW compared to managed forests (P < 0.005). In addition, a lower amount of LDW was observed in the managed forests (P < 0.005). Our data suggest that the managed forests’ lack of Scots pine trees in small-and middle-sized diameter classes indicates the potential risk of conversion of these mixed stands into pure Trojan fir forests. Initial results highlight the importance of large tree retention in managed stands to enhance biological diversity.
Determination of deadwood volume & the affecting factors in Trojan fir forests
(2017-01-01) Topacoǧlu O.; Kara F.; Yer E.N.; Savci M.
Deadwood is one of the important components of forest ecosystems since it is considered as an indicator of resource availability and biodiversity, an important carbon stock, and habitat for insect and fungal species. Removal of dead trees from forests may result in the elimination of many species, and also reduce the number and density of species. Trojan fir (Abies nordmanniana subsp. equi-trojani) is known to be rich in species composition; however, our knowledge on the amount and type of deadwood (i.e. standing or lying) in these forests is limited. Thus, in this study, deadwood quantity and type in Trojan fir forests were determined. In addition, less is known about the factors that influence the amount of deadwood volume; therefore, the effects of stand type, elevation (m), aspect, quadratic mean diameter (QMD) (cm), basal area (BA) (m2 ha-1) and stand volume (m3 ha-1) on deadwood volume were also observed. Stand type, QMD and BA significantly affected the volume of deadwood in Trojan fir forests while stand volume, elevation and aspect had no influence on the deadwood volume. In comparison to the values in the literature, the amount of deadwood observed seems to be acceptable across all stand types. Given the initial results from this study, it can be recommended that large scale deadwood assessments are needed in Turkey, and it can be combined with the current inventory system.
Development and anatomical traits of black pine on an abandoned agricultural land compared to forested areas
(2021-09-01) Kara F.; Keleş S.Ö.; Loewenstein E.F.
Global acreage of forested lands has increased in some countries. At least some of this increase is due to the natural conversion of abandoned agricultural lands into forests. However, little is known about how these new stands develop on abandoned agricultural lands in comparison with natural regeneration of existing forests. Specifically, knowledge of how black pine (Pinus nigra Arnold) naturally establishes and develops on abandoned agricultural lands is limited. In this study, we examined the density and growth of black pine saplings as well as some morphological and anatomical characteristics on an abandoned agricultural land (AAS). These data were compared with those observed in a naturally regenerated stand (NRS), and in a forest opening (FOS). The greatest sapling density was observed in the NRS site, while sapling growth and stem biomass were higher in AAS followed by NRS and FOS. Moreover, each study site exhibited site-specific morphological and anatomical traits in their saplings. Our findings showed that site treatments and overstory openness would both play crucial role for establishment and development of black pine.
Effects of basal area on survival and growth of longleaf pine when practicing selection silviculture
(2017-01-01) Kara F.; Loewenstein E.F.; Brockway D.G.
Aim of study: Uneven-aged (UEA) management systems can achieve multiple-use objectives, however, use of UEA techniques to manage longleaf pine (Pinus palustris Mill.) forests are still open to question, because of the species’ intolerance of competition. It was our aim to examine the influence of different levels (9.2, 13.8 and 18.4 m2 ha-1) of residual basal area (RBA) on longleaf pine seedling survival and growth following three growing seasons. Area of study: This study was conducted at the Escambia Experimental Forest, located on the Southern Coastal Plain of Alabama, in the southeastern United States. Material and Methods: Selection silviculture was implemented with the Proportional-Basal Area (Pro-B) method. Prescribed burning was conducted before seed dispersal and in the second year after germination. Photosynthetically active radiation (PAR) was measured under the canopy in the study plots. Survival and growth of longleaf pine seedlings were observed for three growing seasons. Main results: An inverse relationship was found between the number of germinants and RBA, but the mortality of germinants and planted seedlings was not affected by RBA. At age three, an inverse relationship was observed between root-collar diameter (RCD) growth of the germinants and RBA, but RCD growth of planted seedlings was not affected by RBA. Most of the study plots contained more than the projected number of seedlings needed to sustain the target diameter structure. Research highlights: Long-term continuous monitoring of seedling development and recruitment into canopy is required to determine the efficacy of UEA management. However, current data suggest that UEA methods may be a viable alternative to the use of even-aged (EA) methods in longleaf ecosystems.
Effects of canopy structure on growth and belowground/ aboveground biomass of seedlings in uneven-aged trojan fir stands
(2018-10-01) Kara F.; Topaçoğlul O.
Growth and survival of understory seedlings are infl uenced by their interactions with the environmental variables. The understanding of the relationships between stand density, canopy structure, and understory seedlings’ growth help forest managers conduct successful establishment through natural regeneration. In this study, the infl uence of stand basal area (BA) (m2.ha-1), photosynthetically active radiation transmitted through canopy (PART), leaf area index (LAI), height-to-crown base (HCB) and aspect on the root-collar diameter (RCD) (mm) growth, height growth (cm) and belowground/aboveground biomass (g) of seedlings is observed in uneven-aged Trojan fi r stands. Seedling growth and belowground/aboveground biomass models were developed for fi ve growing seasons after germination. PART, aspect and HCB were found to be the most strongly related to RCD and height growth of Trojan fi r seedlings. PART and aspect explained the most variance in belowground/aboveground biomass of the seedlings. The data also showed that the light transmitted through the canopy was the most signifi cant predictor of understory seedlings growth; thus, PART reaching understory can accelerate the development of sub-canopy layers in uneven-aged Trojan fi r stands. Although survival of Trojan fi r seedlings is usually high under canopy, results suggest that complete canopy closure should be avoided even in stands of shade-tolerant species such as Trojan fi r to increase a seedling’s vigor for its successful recruitment into middle and overstory. The fi ndings of this study will be helpful for forest managers to enhance the establishment and recruitment of Trojan fi r seedlings in uneven-aged stands.
Effects of light transmittance on growth and biomass of understory seedlings in mixed pine-beech forests
(2022-12-01) Kara F.
Seedling growth as well as aboveground and belowground biomass allocation is mostly influenced by Light Transmittance (LT) (%) through the canopy. The knowledge of how understory light conditions affect seedling growth and biomass of different species in mixed forests is not well documented. Thus, it is essential to quantify the effects of light on the growth and biomass of understory seedlings. Given their advantages over pure forests, these quantitative understandings are especially crucial in mixed forests with species whose light demand and shade tolerance vary. This research examined the growth responses of natural-origin Scots pine (Pinus sylvestris L.), black pine (Pinus nigra Arnold.) and Oriental beech (Fagus orientalis L.) seedlings to LT (%) through the canopy in their mixed stands. Linear mixed-effect models were utilized to examine the influence of LT (%) on the seedlings. Moreover, allometric equations for estimating the aboveground biomass and belowground biomass of seedlings were developed for each species. Seedling height, and aboveground and belowground biomass after five years of germination were most significantly affected by LT (%) and tree species in the mixed pine-beech stand (p < 0.001). Biomass models for each species included different variable combinations of seedling height, root-collar diameter, LT (%), and their interactions. This study demonstrates the importance of canopy structure and overstory disturbances for the maintenance of mixed pine-beech forests since canopy structure significantly contributes to the understory light environment.
Effects of light transmittance on growth and biomass of understory seedlings in mixed pine-beech forests
(2022-12-01) Kara F.; Kara, F
Seedling growth as well as aboveground and belowground biomass allocation is mostly influenced by Light Transmittance (LT) (%) through the canopy. The knowledge of how understory light conditions affect seedling growth and biomass of different species in mixed forests is not well documented. Thus, it is essential to quantify the effects of light on the growth and biomass of understory seedlings. Given their advantages over pure forests, these quantitative understandings are especially crucial in mixed forests with species whose light demand and shade tolerance vary. This research examined the growth responses of natural-origin Scots pine (Pinus sylvestris L.), black pine (Pinus nigra Arnold.) and Oriental beech (Fagus orientalis L.) seedlings to LT (%) through the canopy in their mixed stands. Linear mixed-effect models were utilized to examine the influence of LT (%) on the seedlings. Moreover, allometric equations for estimating the aboveground biomass and belowground biomass of seedlings were developed for each species. Seedling height, and aboveground and belowground biomass after five years of germination were most significantly affected by LT (%) and tree species in the mixed pine-beech stand (p < 0.001). Biomass models for each species included different variable combinations of seedling height, root-collar diameter, LT (%), and their interactions. This study demonstrates the importance of canopy structure and overstory disturbances for the maintenance of mixed pine-beech forests since canopy structure significantly contributes to the understory light environment.
Effects of stand types on recreational preferences of society in the Sub-Alpine Zone, northern Turkey
(2022-11-01) Varol T.; Özel H.B.; Kara F.; Çavuş Kara İ.; Ayan S.
The main objective of this study was to examine how different stand types influenced the tendency of visitors for varying recreational activities (i.e., hiking, trekking, camping and hunting) from 1993 to 2018 in the surrounding areas of Uluyayla Natural Recreation Site in Bartin, northern Turkey. A total of 627 visitors were selected on a voluntary basis, and questioned in the form of questionnaire. Most of the participants were in the age of 21–40 years old, and they were mostly (62.4%) male. Most of the participants (82.7%) lived in cities, while 62.8% of them were tourists when visiting the site. In determining the preferences of the visitors regarding the stand types for different recreational activities, several images of each stand were shared with them, and they were asked which stand type they would prefer for a given recreation activity (i.e., hiking, tracking, camping and hunting). A range of options from 1 to 5 in Likert’s scale was used in evaluating the given responses. The degree of positive and negative effects was examined via trend analysis. It was found that stand type had influence on the preferences of visitors regarding the recreational activities. In general, unmanaged and moderately treated stands were more preferred by visitors for the recreational purposes, compared to the previously managed stands. On the other hand, visitors’ preference for the activities were different during two periods (i.e., 1993–2005 and 2006–2018). For each recreational activity, there was an increasing trend from 1993 to 2018. There had been a continuous increase for hunting since 1996, and for trekking and camping after 1999. The increases between 1993–1996 and 1996–1999 were likely due to the increasing awareness of the society as a result of the training and consciousness raising activities for nature conservation. The demand on the recreational activities continuously increased in unmanaged and moderately treated stands, while no significant changes were examined in the previously managed stands. The study points out that forest planning and management should consider different needs of visitors for recreational infrastructure.
Impacts of urban headwater disturbances on downstream sediment loading where streamside management zones for forest harvesting activities are present downstream
(2017-12-01) Cavus I.; Kalin L.; Kara F.
Watershed disturbances caused by land use/land cover (LU/LC) change, intensive forestry practices, and other forms of watershed disturbance are known to negatively affect water quality, if best management practices (BMPs) are not present. Disturbances near or around headwaters where BMPs are absent or are inadequate may impact downstream water quality and stream ecology regardless of the presence of downstream BMPs. In this study, the recovery of two small forest-dominated watersheds (WW and EW) in Auburn, Alabama, USA, was monitored 6-years after a partial clearcut was done. The streamside management zone (SMZ) in WW was also partially harvested shortly after the partial clearcut to improve its sediment trapping effectiveness over the long-term. The hydrology and sediment transport in these watersheds were expected to stabilize over this period, however, new disturbances in the headwaters of both watersheds changed the watershed dynamics. Streamflow and sediment load were examined over a 15-month period from February 2014 to May 2015. The clearcut in WW and EW, and the partially harvested SMZ in WW seemed to have recovered; however, substantial amount of sediment load were measured across all monitoring sites in both watersheds as a result of upstream disturbances. This study emphasizes the necessity of watershed management as a whole, and the importance of BMP applications within the entire watershed. It also highlights the fact that watershed management and BMP implementation is a dynamic process, thus, strategies and techniques need to be continuously adapted in response to environmental changes.
Influence of stand density and canopy structure on the germination and growth of Scots pine (Pinus sylvestris L.) seedlings
(2018-12-01) Kara F.; Topaçoğlu O.
Since the natural regeneration of Scots pine forests is known to be difficult, the effects of canopy structure and environmental variables such as light on germination, seedling growth, and mortality need to be well understood. The knowledge on the relationships between canopy structure, environmental variables, and seedling growth have been helpful for forest managers to formulate silvicultural prescriptions that enhance seedling recruitment. In this study, the influences of stand basal area (BA) (m2 ha−1), leaf area index (LAI), light transmittance (LT), and height-to-crown base (HCB) on germination and seedling growth were explored in a naturally regenerated Scots pine forest in Kastamonu, Turkey. The number of germinants was observed following germination, and total root-collar diameter (RCD) and height of seedlings were monitored after five growing seasons following germination. BA, LAI, LT, and HCB were also examined to determine which variable has more influence on Scots pine seedlings. All variables (i.e., BA, LAI, LT, and HCB) had significant influence on the total seedling growth over a 5-year period. LT was the most significant predictor for total RCD growth and height growth of Scots pine seedlings. The data support the importance of light transmittance through the canopy, along with vertical canopy structure (i.e., HCB) when considering seedling development under a stand canopy.
Initial responses of containerized black pine (Pinus nigra arnold) seedlings to leaf removal prior to out-planting
(2018-01-01) Kara F.; Topacoglu O.
The initial survival and growth of seedlings following out-planting affect the success of plantation activities. Due to transplanting shock, mortality is usually higher and the growth rate is lower in the first growing season following out-planting. In this study, the influence of leaf removal on the initial survival and growth of containerized black pine (Pinus nigra Arnold) seedlings was observed. Thirty seedlings were randomly assigned to one of four treatments: 0%, 25%, 50%, and 75% removal of the existing needles. Height growth, root-collar diameter (RCD) growth, increase in dry stem mass and dry root mass, and mortality were observed during the first growing season following out-planting. All seedlings survived the first growing season. Removal of needles did not affect the height growth, RCD growth, or dry stem mass of the seedlings. However, there was a statistically significant relationship between the removal of needles and the dry root mass; the dry root mass increased with increasing removal of needles. The initial results show that better root development is associated with needle defoliation. However, long-term observations of the seedling responses are recommended.
Onset of canopy closure for black pine, Turkish red pine and Scots pine forests
(2018-01-01) Kara F.; Topaçočlu O.
Canopy closure plays an important role in regeneration and management activities in forestry. Thus, determining the density at which canopy closure occurs is important for the success of silvicultural treatments. Turkish red pine (Pinus brutia Tenore), black pine (Pinus nigra J.F. Arnold) and Scots pine (Pinus sylvestris Linnaeus) forests are usually managed at a density that is near or below the canopy closure. Residual stand density during the management of these species is commonly described by stand basal area - BA (m2 ha-1), however, the BA levels for the canopy closure have not been clearly indicated for these species. The minimum density for the onset of canopy closure (DOCC) was determined for Turkish red pine, black pine and Scots pine forests in this study. DOCC values were compared across the species. For the DOCC, the maximum tree area that a tree can occupy under open-grown conditions was used. The DOCC curves of black pine and Scots pine seem to be similar, but the canopy closure in Turkish red pine forests occurs with fewer trees per hectare for a given mean tree diameter. According to the DOCC curves, regeneration and tending activities will be more practical and effective in these forests.
Sixth grade students’ skills of using multiple representations in addition and subtraction operations in fractions
(2018-03-01) Kara F.; Incikabi L.
The current study aims to show the transition skills of sixth grade students between the representations (numerical, model, number line and verbal) given in addition-subtraction operations in fractions and to analyse the ability of the students to construct each representation type. In this research, case study method was used in terms of the subject and process followed. The study group of the research is the sixth grade students of three middle schools in Kastamonu province placed in the northern part of Turkey. The research participants consisted of 59 students, 31 of which are male and 28 of which are female. Data collected through “Multiple Representations in Fraction Operations Test”. According to research findings, it has been determined that the achievement of students in using different representations in operations with fractions is higher in addition operation compared to subtraction operation. In addition, it turns out that students are more successful in numerical-numerical, model-model, model-numerical, and numerical-model transitions compared to other transitions in both operation types. It was also found out that students fail in other representation types such as number line and verbal representation transition situations.