Effects of potential PAR on shoot extension in juveniles of the main tree species in a Japanese temperate forest

Abstract

We studied the relationship between potential photosynthetically active radiation (PAR), estimated from hemispherical photographs, and shoot extension rates of juveniles of 12 seral tree species. We distinguished between direct light site factor (DIR), diffuse light site factor (DIF), and gap light index (GLI). We used a log‐linear model to relate growth to DIR, DIF and GLI. Potential PAR explained shoot growth rates significantly in 33 cases out of 36 (12 species × 3 PAR). DIF explained the shoot extension rates better than DIR and GLI for 10 of the 12 species. The mean values of maximum shoot extension rates of the tolerant, the intermediate and the intolerant species were 52.4 cm year–1, 64.3 cm year–1 and 87.7 cm year–1, respectively. The maximum shoot extension rates of the tolerant and the intolerant species were recorded in about 50% DIF and more than 70% DIF, respectively. The minimum light level for seedling establishment of the intermediate and intolerant species was more than 20% DIF. We explained distribution characteristics and shoot extension of the species in relation to light in terms of shade tolerance. Predictions based on light‐growth curves and maximum growth curves were similar to field observations made elsewhere, suggesting that these models may be useful to predict extension growth of juvenile trees in mixed species stands.

Why do lower order branches show greater shoot growth than higher order branches? Considering space availability as a factor affecting shoot growth

“…As numerous studies have shown, light environment is one of the most important external factors influencing tree growth (e.g., Canham 1988;Tolvanen 1995;Ishida and Peters 1998;Kawamura and Takeda 2002;Dalling et al 2004). However, for Cleyera japonica, a broad-leaved evergreen woody species, the hierarchical shoot growth according to the branching orders could not be explained only by local light environments (Suzuki 2003): annual shoot length of C. japonica was greater for the lower-order branches when light environments were comparable, although annual shoot length and light environment were positively correlated within same-order branches.…”

Morfologia e estabelecimento de plântulas de Cryptocarya moschata Nees, Ocotea catharinensis Mez e Endlicheria paniculata (Spreng.) MacBride - Lauraceae

“…Observações semelhantes foram relatadas por Chandrashekara & Ramakrishnan (1993), em estudo sobre a germinação, estabelecimento e crescimento de plântulas de espécies arbóreas indianas de diferentes estágios sucessionais, dentre elas Actinodaphne malabarica Balakr., classificada como secundária tardia. Similarmente, Ishida & Peters (1998) mostraram haver relação significativa entre a radiação fotossinteticamente ativa (RFA), estimada através de fotografias hemisféricas, e as taxas de crescimento caulinar de 12 espécies arbóreas japonesas, dentre as quais Neolitsea aciculata (Blume) Koidz., tolerante ao sombrea-mento. Adicionalmente, Pinto et al (1993) encontraram que plântulas de Licaria canella (Meissn.)…”

Height growth, diameter-height relationships and branching architecture of Pinus massoniana and Cunninghamia lanceolata in early regeneration stages in Anhui Province, eastern China: effects of light intensity and regeneration mode

“…King, 1994;Pacala et al, 1994;Ishida and Peters, 1998;Popma and Bongers, 1998) and for trees in environments with relatively high water and nutrient availability (e.g. disturbed forest stands in regions with suffi cient precipitation, including the study site; see below for details), light is often limited due to strong competition among neighboring trees, our fi rst objective is to clarify strategies of P. massoniana and C. lanceolata to cope with low light availability.…”