Growth allocation between height and stem diameter in nonsuppressed reproducing Abies mariesii trees

Abstract

To understand the growth patterns with respect to competition and leaf-mass increase in reproducing trees, growth allocation between height and stem diameter was examined for nonsuppressed reproducing Abies mariesii trees in a subalpine forest in northern Honshu, Japan. The growth allocation was analyzed by dividing the relative growth rate of the stem volume into the relative contributions of height and stem-diameter growth. During a 9-yr period, height growth and seed-cone production showed obvious annual variation, while stem-diameter growth recorded moderate variation. For two of three years of seed-cone production during the 9-yr period, trees with larger seed-cone production were associated with less height growth in the following year of seed-cone production; however, there was no trend of height growth in the year of seed-cone production. In the following year of mast seeding, trees with larger stem-volume growth were associated with less height growth. This trend was also shown for the relationship between the cumulative stem-volume growth during the 9-yr period and growth allocation to height, suggesting that trees with a larger biomass increase depress the allocation of photosynthate to competition with a large expenditure for reproduction. In contrast to this, trees with a smaller biomass increase might allocate photosynthate to competition with surrounding trees. The results of this study suggest that an increase in reproductive organs during life history and annual variation in reproduction are closely associated with the growth patterns of the stem in A. mariesii trees.

Competition and disturbance affect elevational distribution of two congeneric conifers

“…The number of recruitment trees into ≥DBH 5 cm during two successive censuses was counted for each 10 × 10 m quadrat. It is expected that the recruitment rate is proportional to the amount of parent trees (Uriarte et al, 2005) and that larger trees produce more seeds (Kohyama, 1982; Seki et al, 2013). Seeds possibly come from the outside of the 10 × 10 m quadrat.…”