Eurasian Journal of Forest Science

60-67

Authors: Masashi Konoshima1*, Hiroyuki Hattori1, Atsushi Yoshimoto2

In this study we evaluate and compare different invasive species management scenarios in order to investigate a cost-effective management strategy over space and time. Cost effectiveness matters because budget constraints limit the area that can be treated to mitigate the risk of invasion in any given year. The spatial nature of invasive species spread makes it important to effectively allocate budget resources to control spread over space and time. We develop and use a simulation model to examine and compare the affect of various management strategies on the pattern and extent of invasive species spread, as well as management costs. Our model is based on a biological model that captures the dynamic and spatial aspect of invasion, integrated with a spatially explicit dynamic decision tool. Our model explicitly integrates the tradeoff between management intensity and management cost, and quantifies this tradeoff, which is important information for allocating management efforts efficiently and effectively over space and time.

77-89

Authors: Osman Yalçın Yılmaz1, Orhan Sevgi2, Hüseyin Barış Tecimen2, Serdar Carus3, Ali Kavgacı4, Huseyin Yurtseven1, Ramazan Erdem5

Black pine is very widely distributed in Turkey, with most stands managed by periodic harvesting to meet domestic wood demand. However, scientific knowledge about the spatial structure of stands after thinning is lacking. To correct this deficiency, 12 pure black pine stands in the Alaçam Mountains between 61 and 95 years of age were investigated. The stands were mapped according to spatial tree distribution and thinning grades were determined by both number of trees per hectare and basal area. The numbers of trees in the stands were between 590 and 2163 (before thinning) and between 269 and 1422 (after thinning). Spatial-structure analyses were carried out before and after thinning using a pair correlation function. Graphical illustrations were extracted and visually assessed. In addition, the total areas below and above the theoretical line (g=1) of the pair correlation functions were calculated, and the effects of thinning on these were determined. No change was observed in the slightly thinned sample stands (17, 35, 38, and 56) and only slight changes in the moderately thinned stands (18, 21, 49. and 53). The most striking differences were detected in the intensively thinned stands (59, 68, 76, and 78). Regular areas have increased in parallel with increased thinning applications. In other respects; clustered areas did not decrease along with the increased thinning. The pair correlation function provides a comprehensive explanation of the effects of thinning on stand spatial structure.

1-19

Authors: İsmail Şafak1*, Altay Uğur Gül2, Mehmet Emin Akkaş1, S. Ümit Portakal3, Mustafa Gediklili4, Ş.Mümtaz Kanat5

In this research, efficiency covering the years 2007-2009 of the forest sub-districts in the Izmir Forestry Regional Directorate was evaluated using 15 variables by fuzzy data envelopment analysis. Fuzzy data envelopment analysis solutions were carried out using the data range. Fuzzy data was established by defining the lower, central and upper limits on the basis of the triangular membership function. These data are converted into interval data considering the approach of Zimmermann (1991) α cutting set. Thus, the upper and lower limits of efficiency values were obtained at five different α (0; 0.25; 0.50; 0.75 and 1.00) using fuzzy data envelopment analysis. Then inefficient forest sub-districts were listed from best to worst using the Minimax Regret-Based Approach. As a conclusion, Göçbeyli, Sarıgöl, Kınık, YeniŞakran and Kemalpaşa forest sub-districts have the best efficiency. On the other hand, Salihli, Gördes, Akhisar, Manisa, Ödemiş and Tire forest sub-districts have the worst efficiency.

38-50

Authors: Ali KAVGACI1*, Orhan SEVGİ2, Hüseyin Barış TECİMEN, Osman Yalçın YILMAZ3, Serdar CARUS4, Türker DÜNDAR5

Pinus nigra dominated forests at Alaçam Mountains at the northwest of Anatolia were sampled, elaborated and classified since those forests represents one of the most typical distiribution of Pinus nigra in Turkey and were not subjected to any phytosociological study. Additionally, pure Fagus orientalis stands at the upland of the mountains were added to the analysis. The ecological conditions were assessed by topographical and environmental (latitude and longitude) factors. Forest vegetation at Alaçam Mountains can be divided into four groups. Three of these communities represent the P. nigra forests whereas the last is formed by pure F. orientalis forest. It was established that the most important ecological factor is altitude, while the other factors do not correlate with the floristic differentiation of the communities. The names of the communities along the altitudinal gradient are as follow: Cistus laurifolius-Pinus nigra dominated forest, Pteridium aquilinum-Pinus nigra dominated forest, Fagus orientalis-Pinus nigra dominated forest, and Galium odoratum-Fagus orientalis dominated forest. These results indicate the rich diversity and differentiation at short distances at the study area, and altitude is the determining ecological factor on this richness. They also explore the need of a broad scale phytosociological study on Pinus nigra forests along whole Anatolia to define their floristic and ecological diversities.