Effects of cutting on community structure of a Quercus mongolica var. grosseserrata: Secondary stand along topographical gradient

Community structure and stem growth patterns of individual species in a Quercus mongolica var. grosseserrata secondary forest in the Tohoku Region of northern Japan have been investigated. 1 ) There were 35 species/1.05ha in terms of tree species with a diameter at breast height (DBH) of 5 cm or larger, and the stand basal area was 38.6 square m /ha. 2 ) The relationships between DBH and top height for each species were analyzed using an expanded allometric equation. Shade-intolerant species such as Q. mongolica, Q. serrata, and Cornus controversa represented a steep initial slope with respect to the DBH-height allometry. In contrast, shade-tolerant species such as Acer japonicum, Fagus crenata, and Ilex macropoda represented a gentle initial slope for the DBH-height allometry. These results appear to reflect the differences in assimilate partitioning between height growth and stem diameter growth in relation to the shade tolerance of species. 3 ) For almost all species except F. crenata, species dominance patterns along the topographic gradient in this forest were approximately consistent with those in other forests. 4 ) Since DBH distributions of Q. mongolica, Q. serrata, and Magnolia obovata indicated a unimodal shape, many trees in this forest should be aggregated into a single cohort. However, a 3800 square m patch, in which large trees with a DBH of 50 cm or larger were not located, was found in this forest. Furthermore, multi-stem clumps of Q. mongolica as well as Carpinus laxiflora, Q. serrata, and F. crenata trees have aggregated in this patch. Therefore, this patch appears to have been created by cutting, and the large trees present have remained after cutting. Regeneration of F. crenata trees might be affected by sensitivity to light rather than moisture and nutrient in this forest. 5 ) The number of single stem trees was greater than that of multi-stem clumps for Q. mongolica. Since three-fourths of the large trees were Q. mongolica trees, seed supply from remaining Q. mongolica trees may promote seedling regeneration and subsequently increase the Q. mongolica's dominance.