Application of a self-organizing map (SOM) for grouping of oak ecosystems by different characteristics in Bulgaria

Абстракт

Neural networks (NNs) can use a lot of heterogeneous data that may lack  repeatability and confirmability, as well as analogues in the other systems involved in the analysis,  which is typical for the available ecosystem data. NN have hardly been used for the study of  plant communities in Bulgaria. In this article, xerothermic oak communities in Bulgaria from up  to 180 polygons were studied, and 122 characteristics of the ecotype and plant communities were  included in the analysis. After conducting self-training of the SOM, different groups of polygons  were obtained with respect to soils, exposure, altitude, climate and mixed characteristics. All the  obtained groups correspond to the ecological characteristics of communities, which confirm the  capabilities of SOM for grouping the plant communities for different purposes. 

References:

Angelov S. 1986. About some elements of water balans of conifers and oak forests. - Forest Institute 3: 63-66 (In Bulgarian).

Bondev I. 1998. Overground annual production and biomass of oak forests in the Balkan Mountains. - Ecologie, Grenoble 29 (1-2): 389-392.

Bondev I. 2002. Geobotanical zoning. - In: Kopralev I. (Ed.), Geography of Bulgaria: Physical and socio - economical geography. ForKom Press, Sofia, 336-352 (In Bulgarian).

Bondev I. & Bogoev V. 1981. Contamination of Turkhish forest with lead from motor transport in the Vakarel Heights region. –- In: Third National Botany Conference, Sofia, BAS, 37-42 (In Bulgarian).

Bondev I. & Georgiev N. 1987. Content and dynamics of N, P, K in phytomass of ass. Quercus pubescens + Q. frainetto-Cottinus coggigria–Brachipodium pinnatum in the region of v. P. Eftimovo, Plovdiv. - In: Conference papers of IV National conference of Botany, Sofia, BAS, vol. 3, 16-123 (In Bulgarian).

Bondev I. & Lyubenova M. 1992. Phytomass of tree layer of ass. Quercus frainetto+Quercus cerris-Festuca heterophylla in Vakarel Mountain. – Annuaire de l'Université de Sofia "St. Kl. Ohridski", Faculté de Biologie, Livre 2 - Botanique 82: 197-209 (In Bulgarian).

Bondev I. & Nikolov N. 1983. Overground primary production of bush and herb sinusium in ass. Quercus pubescens + Q. frainetto-Cottinus coggigria– Brachipodium pinnatum in Thracian lowland. – Ekologiya (BAS, Sofia) 12: 23-34 (In Bulgarian).

Bondev I., Georgiev N. & Ljubenova M. 1994. Primary production of the herb synusia in five xerotermic forest ecosystems in the northern regions of Strandza mountain. - Annuaire de l'Université de Sofia "St. Kl. Ohridski", Faculté de Biologie, Livre 2 - Botanique 85: 225-230.

Bondev I., Lyubenova M. & Nikolov N. 1998. Aboveground phytomass and production of the oak stand in two oak associations in the northern regions of Strandzha. - Phytologia Balcanica 3: 87-94 (In Bulgarian).

Bondev I., Nikolov N. & Lyubenova М. 1976. Vegetation cover in the area of stationary research in the Thracian lowland near the village of Patriarch Evtimovo, Plovdiv district. – In: Third National Botany Conference, BAS, Sofia, 367-376 (In Bulgarian).

Broshilova M. & Broshilov K. 2008. Growth and productivity of mixed cultures of oaks (Quercus sp.) and black pine (Pinus nigra Arn.) in the Burgas region. - Forest Science 3: 27-39 (In Bulgarian).

EAA - Executive Environment Agency 2000. Reports. Regions: 1, 4B, 8, 9, 10, 2-4A, 4A. University of Forestry.

Freeman J & Kohonen D. 1995. Neural Networks, Algorithms. Applications and Programming Techniques. Addison-Wesley Publishing Company Inc., 550 pp.

Gateva R. 1994. Studies on the accumulation of microelements from tree species in the Devnya industrial area. - Forest Science 1: 8-15 (In Bulgarian).

Goldberg D. E. 1989. Genetic algorithms in search, optimization and machine learning. Addison -Wesley Professional, 412 pp.

Grupce L. Melovski L. & Mulev M. 1993. Plant biomass and primary production of Quercetum frainetto-cerris macedonicum ecosystem in Galicica national park. - In: Proceeding "100 years since the birth of Acad. B. Stefanov/1894-1979/", Jubilee scientific conference, June 2-3, 1994, Sofia, Bulgarian Academy of Sciences, vol. 2, 85-92.

Kochev H. & Tsanova D. 1978. Study of the primary biological production of ground synusia of two oak associations in Vitosha Mountain. – Fitologiya (Sofia) 10: 19-32 (In Bulgarian).

Kohonen T. 2001. Self-Organizing Maps. 3th Edition. Springer, Berlin, 501 pp.

Kurteva M., Boneva D. & Mashiah E. 2002. Changes in some morphological parameters and accumulation of microelements in tree species from the Pirdop region. - Forest Science 3: 47-63 (In Bulgarian).

Lalova Y. 1994a. Primary productivity of representative forest associations in Northwestern Bulgaria. - Forest Science 2: 10-20 (In Bulgarian). Lalova Y. 1994b.

Studies on the circulation of the main macrobiogens in the oak hornbeam and beech association, Vidin region. - Forest Science 4: 8-16 (In Bulgarian).

Ljubenova M. I. 1995a. Above-ground energy reserves and annual accumulation of energy in shrub and herb layers in ass. Quercus frainetto + Quercus cerris Festuca heterophylla + Poa nemoralis in the Vakarel montains. - Ecology and Protection of the Environment, Skopje 2 (1): 29-35.

Ljubenova M. I. 1995b. Investigations on some functional parameters of tree layer in association Quercus frainetto + Quercus cerris-Crataegus monogyna Brachypodium pinnatum in the Western Balkan mountain. - Annuaire de l'Université de Sofia "St. Kl. Ohridski", Faculté de Biologie, Livre 2 - Botanique 88: 11-18.

Ljubenova, M. I. 1995c. Solar energy utilization and efficiency of an oak forest in the Vakarel mountains. - Ecology and Protection of the Environment, Skopje, 2 (12): 31-35.

Ljubenova M. I. 1997. Utilization and accumulation of Zn and Mn in Quercus frainetto phytomass in different regions of Bulgaria. - Ecology and Protection of the Environment, Skopje 5 (1): 21-28.

Ljubenova M. 1999. Content of Zn, Mn and Fe in leaves, annual branches and bark of Quercus frainetto Ten. from different regions of Bulgaria. – In: Proceedings of the "1st congress of Macedonian ecologists", Ohrid, 20-24.09.1998, vol. 2, 629-643.

Lyubenova M. & Bondev I. 1998a. Aboveground phytomass in a linden-oak forest from Ludogorie (Northeastern Bulgaria). Ecological Protection of Living Environment, Skopje 1 (1): 3-10.

Ljubenova M. & Mirchev St. 1998. Dynamics of Zn, Mn and Fe content in Fagus sylvatica L. phytomass from two beech communities in the Western Balkan mountains. - Journal of Balkan Ecology 1(4): 71 -77.

Lyubenova M. 1992. Energy reserves in the underground phytomass of the association Quercus frainetto + Q. cerris - Festuca heterophylla + Poanemoralis in the Vakarel Mountain. - Annuaire de l'Université de Sofia "St. Kl. Ohridski", Faculté de Biologie, Livre 2 - Botanique 82: 187-196 (in (In Bulgarian).

Lyubenova M. 1995a. Assimilation of solar energy and efficiency coefficient of tree layer in the oak-hornbeam ecosystem in the Western Balkan region. - In: Proceeding "100 years since the birth of Acad. B. Stefanov /1894-1979/",

Jubilee scientific conference, June 2-3, 1994, Sofia, Bulgarian Academy of Sciences, vol. 2., 100-104 (In Bulgarian).

Lyubenova M. 1995b. Investigation of some functional parameters of oak forests in the Central Balkan. - In: Proceeding "70 years of forestry education in Bulgaria", Jubilee scientific session, April 7-9 1995, Sofia, VLT, Sofia, vol. 3, 218-228 (In Bulgarian).

Lyubenova M. 1995c. Study of the energy flow in oak forests of the Zemen Mountain. - In: Proceeding "70 years of forestry education in Bulgaria", Jubilee scientific session, April 7-9, 1995, VLT, Sofia, vol. 3, 228-236 (In Bulgarian).

Lyubenova M. 1996a. Aboveground phytomass and annual production as functional indicators in oak-hornbeam phytocenoses from the Kamchiya Mountain. - In: Proceeding "Second Balkan scientific conference on the study, conservation, and use of forest resources, June 3-5, 1996, Sofia, vol. I, 307- 313 (In Bulgarian).

Lyubenova M. 1996b. Investigations of some structural and functional parameters of an oak forest from the north-eastern Rhodope mountains. - Ecology and protection of the environment, Skopje 4 (1): 3-11.

Lyubenova M. 2004. Phytoecology. Marin Drinov State Publishing House, Sofia, 574 pp. (In Bulgarian).

Lyubenova M. & Bondev I. 1987. Underground phytomass of tree layer of the association Quercus frainetto + Quercus cerris - Festuca heterophylla + Poa nemoralis in the area of village Gabra, Sofia region. - In: Proceedings of the IV National Conference of Botany, Bulgarian Academy of Sciences, Sofia, 3: 72-76 (In Bulgarian).

Lyubenova M. I. & Bondev I. A. 1998. Overground annual production and biomass of oak forests in the Balkan mountains. – Ecologie, Grenoble 29 (1-2): 389- 392.

Lyubenova M. & Dimova R. 2000. Contents of heavy elements in some dendromass fractions from the forest ecosystems in the region of Etropole. - Annual of Sofia University "St. Kliment Ohridski", Faculty of Biology, Book 2-Botany 91: 129-138.

Lyubenova M. & Sazdov Y. 1995. Study on the role of tree layer in the cycle of chemical elements in a xerothermic oak ecosystem of the Western Balkan. - In: Proceeding "100 years since the birth of Acad. B. Stefanov/1894-1979/", Jubilee scientific conference, June 2-3, 1994, Sofia, Bulgarian Academy of Sciences, vol. 2, 93-100 (In Bulgarian).

Lyubenova M., Bondev I. & Atanasova B. 1996. Study of the structural and functional state of the oak-hornbeam forest in the Western Sredna Gora. – Gorska Misul [=Forestry Thoughts] 3 (8): 1-11 (In Bulgarian).

Lyubenova M., Sokolovska M. & Bratanova–Doncheva Sv. 2008. Primary production of the herb synusia in five xerotermic forest ecosystems in the northern regions of Strandza mountain. - Silva Balkanica 9 (1): 41-58.

Melovski L., Mulev M. & Derlieva L. 1994. Above-ground phytomass in Quercetum frainetto - cerris - macedonicum forest ecosystem in the Veles foothill area (central Macedonia). - Ecology and Protection of the Environment 47: 107-125.

Meshinev T. & Nikolov V. 1986. Biological productivity of an association from the region of the Elensky Fore-Balkan. – Ecologiya (Sofia) 19: 3-18 (In Bulgarian).

Meshinev T. & Nikolov V. 1987. Leaf surface index and intensity of the production process in two oak communities from the Elensky Fore-Balkan. - In: Proceedings of the IV National Conference on Botany, BAS, 59-64.

Mouton C., Myburgh J. C. & Davel M. H. 2020. Stride and Translation Invariance in CNNs. - In: Gerber A. (Ed.), Artificial Intelligence Research. SACAIR 2021. Communications in Computer and Information Science. Springer, Cham, 1342: 267–281.

Ninov N. 1995. Primary productivity and functioning of xerothermic oak ecosystems in Bulgaria. - Forestry Science 3: 3-15 ((In Bulgarian). Ninov N. 2002.

Soil – geographical zoning. - In: Kopralev I. (Ed.), Geography of Bulgaria: Physical and socio - economical geography. ForKom Press, Sofia, 300-303 (In Bulgarian).

Popov E. 1999. Genetic resources of the common oak. - Forestry Science 1: 11-21 (In Bulgarian).

Varbanov S., Chipev N. & Bratanova–Doncheva Sv. 2005. Neuron sets and genetic algorithms using for chestnut forests state assessment in Belasitza mountain. - In: First National Scientific Conference of Ecology “Biodeversity, Ecosystems, Global changes”, Sofia, Bulgaria. Petekston Publishing House, Sofia, 131-139 (In Bulgarian with English summ.).

Velev St. 2002. Climatic zoning. - In: Kopralev I. (Ed.), Geography of Bulgaria: Physical and socio - economical geography. ForKom Press, Sofia, 155-157 (In Bulgarian).

Wehrens R., Lutgarde M. & Buydens C. 2007. Self- and Super-organizing Maps in R: The Kohonen Package. - Journal of Statistical Software 21 (5): 1-19. https://doi.org/10.18637/jss.v021.i05

Yurukova L. & Bondev I. 1990. Content of macro and microelements in the main tree species of nine xerothermic oak coenoses in Burgas region. – Forestry Science 2: 31-37 (In Bulgarian).