Journal of Forest Science, 2019 (vol. 65), issue 8

Accelerated formation of Siberian pine (Pinus sibirica Du Tour) stands: a case study from SiberiaOriginal Paper

Nikita Debkov

J. For. Sci., 2019, 65(8):291-300 | DOI: 10.17221/48/2019-JFS  

Under natural conditions, Siberian pine Pinus sibirica begins to produce commercial cone yields of nuts relatively late (after more than 100 years). The aim of this study was to summarise the experience of the directed formation of Siberian pine forests in Siberia. Experimental objects included plots with traditional thinning of varying intensity and frequency as well as chemical treatment. We assessed the parameters of the stand and its seed production dynamics. Only stands with a minimum density (395-435 trees.ha-1) had a normal seed production energy (1.5 or more cones per shoot). Over-dense stands (830-930 trees.ha-1) were characterised by a low...

The effect of forest management on the frequency of dangerous trees in the Northern forests of IranOriginal Paper

Mehrdad Nikooy, Alireza Ghomi, Farzam Tavankar

J. For. Sci., 2019, 65(8):301-308 | DOI: 10.17221/51/2019-JFS  

A study of work accidents in forests has shown that dangerous trees play an important role in forest accidents. Despite the importance of safe working environments for forestry operations, the definition of these areas in natural forests is still unclear. Dangerous trees are considered those snagged with broken branches and a canopy or ones with dead trunks and stumps that have a hazard potential to the forest workers. This study investigates the frequency of these trees in the managed and unmanaged forests in the Caspian forests of Iran. In order to do the study, 15 circular plots with a total area of 1,000 square metres in two studied parcels were...

The effect of some commercial plant oils on the pine processionary moth Thaumetopoea pityocampa (Lepidoptera: Notodontidae)Original Paper

Şeyma Yigit, Islam Saruhan, Izzet Akça

J. For. Sci., 2019, 65(8):309-312 | DOI: 10.17221/63/2019-JFS  

Thaumetopoea pityocampa (Lepidoptera: Notodontidae) is one of the major forest pests and causes serious damage especially to pine trees. Mechanical and chemical methods are used in the control of this pest in Turkey's forests. In recent years, a chemical control has been the most preferred method against this pest. Due to the chemical control's harmful effects on the environment and the human health, alternative methods of control are being emphasised today. There are many studies on the use of plant oils against pests in agricultural areas. However, studies on the effect of plant oils against the pine processionary larvae are very limited....

Variations in the length of Scots pine (Pinus sylvestris L.) needles under the influence of climatic factors and solar activity in different conditions of northern taigaOriginal Paper

Olga N. Tyukavina, Nikolay A. Neverov, Alexander L. Mineev

J. For. Sci., 2019, 65(8):313-320 | DOI: 10.17221/47/2019-JFS  

The aim of the study was to assess the influence of climatic factors on the growth of pine needles in different conditions of the water regime of soil. Studies were conducted in lichen pine forests, cowberry pine forests, blueberry pine forests, shrub-sphagnum pine forest and pine on swamp in the Arkhangelsk forestry regions (northern taiga). The needle length is influenced by solar activity (the Wolf number). The effect of solar activity on increasing the needle length is greatest in optimal growing conditions. In northern taiga conditions, air temperature is the main climatic factor affecting the growth of needles. In the blueberry, cowberry and...

A smoke image segmentation algorithm based on rough set and region growingOriginal Paper

Haitao Wang, Yanli Chen

J. For. Sci., 2019, 65(8):321-329 | DOI: 10.17221/34/2019-JFS  

Because the image fire smoke segmentation algorithm can not extract white, gray and black smoke at the same time, a smoke image segmentation algorithm is proposed by combining rough set and region growth method. The R component of the image is extracted in the RGB colour space, the roughness histogram is constructed according to the statistical histogram of the R component, and the appropriate valley value in the roughness histogram is selected as the segmentation threshold, the image is roughly segmented. Relative to the background image, the smoke belongs to the motion information, and the motion region is extracted by the interframe difference method...