Herbaceous Response to Canopy Cover, Light Intensity, and Throughfall Precipitation in Coniferous Forests

Abstract

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Managing succession in conifer plantations: converting young red pine (Pinus resinosa Ait.) plantations to native forest types by thinning and underplanting

“…Forest canopies have a substantial influence on the understory environment, buffering temperature changes, reducing light intensity, changing the spectral quality of solar radiation, and intercepting a significant proportion of precipitation (Anderson et al 1969, Aussenac 2000. The growth and abundance of understory vegetation beneath intact forest canopies are strongly limited by heavy shade, reduced precipitation inputs, and root competition for moisture with overstory trees (Anderson et al 1969, Canham et al 1990, Bazzaz and Wayne 1994.…”

“…The growth and abundance of understory vegetation beneath intact forest canopies are strongly limited by heavy shade, reduced precipitation inputs, and root competition for moisture with overstory trees (Anderson et al 1969, Canham et al 1990, Bazzaz and Wayne 1994. Increased light, soil moisture, and nutrient availability and creation of microsites for colonization associated with canopy disturbance promote understory succession, dependent on the inten- For personal use only.…”

“…These species are favoured by the improved light and soil moisture conditions of canopy gaps, but they decrease in frequency with time after disturbance as woody species begin to dominate the understory (Anderson et al 1969, Moore and Vankat 1986, Thomas et al 1999. Conversely, cryptogam richness was higher in the sheltered understory microenvironments of the CN plots.…”

Plant Assemblages Along an Altitudinal Gradient in Northwest Himalaya

“…Also, trees alter microclimate under them by way of through fall (Anderson et al 1968), release of allelochemicals that inhibit germination of seeds (Gupta et al 2007), decrease in pH of soil (Yadav 1999), temperature change (Hazra and Patil 1986), reduction in LAI of herbage (Sharma and Gupta 2005a&b) and enhancement in spatial heterogeneity of soil fertility (Muller 2003;Neufeld and Young 2003), which regulates the behaviour of plants. In khair forest the decrease in solar influx under trees was least amongst forests because the crown of khair trees is sparse and the solar interception by trees is low (Table 1).…”

Overstory Community Composition and Elevated Atmospheric CO2 and O3 Modify Understory Biomass Production and Nitrogen Acquisition

“…Total understory biomass, individual species biomass, and species composition of the understory vegetation are known to be affected by the amount of light reaching the forest floor, which is driven by overstory species composition, as well as stand and crown structure (Alaback, 1982;Berger and Puettmann, 2000;Hunt et al, 2005;Legare et al, 2002;Peek et al, 2001). Understory species composition and biomass are also affected by leaf litter (Harrington et al, 2003), productivity (Adkison and Gleeson, 2004), soil nutrient concentrations (Hunt et al, 2005), nitrogen deposition rate (Rainey et al, 1999), throughfall precipitation (Anderson et al, 1969), above and below ground competition with overstory vegetation (Harrington et al, 2003;Riegel et al, 1992), disturbance (Moser et al, 1996), and successional dynamics (Gleeson and Tilman, 1990).…”