Stand structure and dynamics during a 16-year period in a sub-boreal conifer–hardwood mixed forest, northern Japan

Abstract

The stand structure and regeneration dynamics of trees > 2.0 m in trunk height were studied during 1982-1998 in a 1-ha plot in a sub-boreal conifer-hardwood mixed forest, northern Japan, with a dense dwarf bamboo in the understory. Total density was low in 1982 (651 trees/ha), as compared with other forests in Japan. Quercus crispula was dominant in the upper canopy layer but their saplings were rare, while Acer mono, Acer japonicum and Abies sachalinensis were dominant in the sub-canopy and understory layers with many saplings. Mortality of each species was quite low during the census period (average 0.57%/yr), and there was no clear difference among the four species. The age structure of Quercus crispula was bell-shaped with a peak at ca. 200 years, while that of the other three species was weakly reverse-J shaped or a rough plateau. In addition, no recruits growing over a height of 2 m were observed during the census period in Quercus crispula, but many recruits of the other species were observed. These suggest that Quercus crispula depended on episodic disturbances for the persistence of its population. Recruits of the three species except for Quercus crispula did not concentrate in canopy gaps probably because of the dense dwarf bamboo cover there. They showed a negative spatial association with their own canopy trees, but a positive association with canopy trees of Quercus crispula. Most of the crowns of the three species (Abies sachalinensis and the two Acer spp.) were lower than that of overtopping Quercus crispula. These spatial associations between recruits and canopy trees brought about the competitive effect of Quercus crispula on the growth rates of other species and that of itself. However, the low mortality of trees taller than 2 m indicates that intra-and interspecific competition was not strong as a structuring force of the tree community. Our long-term study suggests that factors affecting recruitment (disturbances and dwarf bamboo in the forest floor) are more important for species coexistence than intra-and interspecific competition between trees taller than 2 m.

Oxygen and carbon isotopic ratios of tree-ring cellulose in a conifer-hardwood mixed forest in northern Japan

“…In 1982 and 1998, the stand structure and regeneration dynamics were studied in detail in a 1 ha plot in this forest (Takahashi et al, 2003). Total density of trees (height >2 m) was 752 trees/ha in 1998.…”

Effects of Temperature and Light Conditions on Growth of Current-Year Seedlings of Warm-Temperate Evergreen Tree Species and Cool-Temperate Deciduous Tree Species

“…japonica at the two temperature conditions (T2 and T3) warmer than the current distribution range suggests that the natural distribution ranges of the two species are not determined by optimal temperature conditions alone (i.e., the concept of ecological niche). Although Q. crispula is a common species in oldgrowth deciduous broad-leaved forests (Masaki et al, 1992;Takahashi et al, 2003b), Q. crispula is recognized as a gap-dependent species (Yamamoto, 1989). It is reported that saplings of deciduous broad-leaved species distributed mainly in canopy gaps in an evergreen broad-leaved forest (Miura et al, 2001).…”

Multi-Species Stand Classification: Definition and Perspectives

“…A frequent stand classification criterion used in research studies is often based on the number of species [22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37] with no reference to the species proportion in the mixture and their spatial arrangement. Few references are found with the proportion of the number of trees and basal area [38][39].…”