عنوان مقاله [English]
Background and objectives: Aims and background: Regeneration success in the most plant species, especially oaks, depends on the acorn distribution and their establishment on proper location for germination and producing vigorous seedling. The most important process that relate spatial pattern of seeding plants to the next generation is seed dispersal. Due to lack of information on acorns distribution in different locations of coppice oak forest in the fragmented middle Zagros, this research aimed to investigate Persian oak acorns distribution pattern in fragmented coppice stands and in different distances from sprouts sprout-clumps and also determining the relation between acorn distribution location (interior and edge of sprout-clumpss, deforested matrix around sprout-clumpss, and abandoned field) and susceptibility to diseases.
Material and methods: The study area located on Kakareza forest catchment, 45 km far from north east of Khoramabad. The Persian oak is the dominant tree species in this forest. In order to sample dispersed acorns, a 1,000-m transect was drawn at the boundary zone between the forests and the abandoned field and 40 perpendicular lines with random lengths, spaced 25 m from each other on this transect were extended. The acorns were sampled at plots of interior, edge and deforested matrix around the nearest patch to the end of perpendicular lines. The acorns also were sampled at the end of perpendicular lines in the plots of abandoned field. The collected acorns were classified to three categories (viable, aborted, and Infested by fungi). The infested acorns by fungi were sent to the laboratory to reconnaissance fungi taxa.
Results: Results and conclusion: Based on the results nearly 85% of collected acorns in forest area were viable. Laboratory results showed that, the most important fungi species that infested acorns, belong to the Penicilium, Rhizopus, Alternaria, and Trichoderma genera. Although, no significant difference were seen in the weight, length, and diameter of acorns in the interior, edge and deforested matrix around sprout-clumpss locations, but there were significant differences in aborted and viable acorns in the three locations. The interior and the edge of sprout-clumpss comprise more acorns and viable acorns than the matrix around sprout-clumpss. There was no significant difference in infested acorns in the above mentioned locations. The interior and the edge of sprout-clumpss comprise more acorns and viable acorns than the matrix around sprout-clumpss. There was no significant difference in infested acorns in the above mentioned locations. Conclusion: These results reveal that forest fragmentation, has major effects on the presence and the pattern of acorn dispersers and consumer's distribution and resulted to limitation of dispersers’ activity. Therefore acorns were trans located to the distances from sprout sprout-clumpss. Due to reduction in the dispersers’ population size and activity, distribution of heavy acorns of the Persian oak near the sprout sprout-clumpss is expected. It is concluded that the anthropogenic disturbances that lead to deterioration of forest oak ecosystems is the most effective factor on acorn dispersion and the probability of successful regeneration decrease with the distance from sprout-clumpss owning to reduction in viable acorns.