Parameter name  Description 

Beam Fraction of Global Radiation  The fraction of total solar radiation that is direct beam radiation (as opposed to diffuse). Expressed as a value between 0 and 1. See more on GLI calculations. 
Clear Sky Transmission Coefficient  Used to determine the amount of solar radiation seen at the plot location. See more on GLI calculations. 
First Day of Growing Season for GLI Light Calculations  The first day of the growing season, as a Julian day (number between 1 and 365). Seeds only get light during the growing season. See more on GLI calculations. 
GLI of Optimum Establishment, 0100  The GLI value of optimum survival for seeds, as a value between 0 and 100. 
Height in m At Which to Calculate GLI  The height, in meters, at which to calculate GLI at the center of each grid cell. 
Last Day of Growing Season for GLI Light Calculations  The last day of the growing season, as a Julian day (number between 1 and 365). Seeds only get light during the growing season. See more on GLI calculations. 
Light Extinction Coeff of Complete Damage Trees (01)  The fraction of light transmitted by the crowns of trees with complete Storm damage. Not required if storms are not used. Expressed as a value between 0 and 1. If storms are used, a value must be supplied for every species. See more on GLI calculations. 
Light Extinction Coeff of Medium Damage Trees (01)  The fraction of light transmitted by the crowns of trees with medium Storm damage. Not required if storms are not used. Expressed as a value between 0 and 1. If storms are used, a value must be supplied for every species. See more on GLI calculations. 
Light Extinction Coeff of Undamaged Trees (01)  The fraction of light transmitted by the crowns of regular live trees (and if storms are being used, trees with no Storm damage). Expressed as a value between 0 and 1. A value must be supplied for every species. See more on GLI calculations. 
Minimum Solar Angle for GLI Calculations, in rad  This is the minimum angle at which sunlight is seen, in radians. Below this value the sky is assumed to be dark due to shading neighbors. See more on GLI calculations. 

Number of Altitude Sky Divisions for GLI Light Calculations  Number of grid cells into which the sky is divided from horizon to zenith, for the purpose of calculating light direction. See more on GLI calculations. 
Number of Azimuth Sky Divisions for GLI Light Calculations  Number of grid cells into which the sky is divided around the horizon, for the purpose of calculating light direction. See more on GLI calculations. 
Slope of Dropoff Above the Optimum GLI  The slope of the line describing the drop off in seedling survival as a function of GLI above the optimum GLI. 
Slope of Dropoff Below Optimum GLI  The slope of the line describing the dropoff in seedling survival as a function of GLI below the optimum GLI. 
Snag Age Class 1 Light Extinction Coefficient (01)  Fraction of light transmitted through the snag tree crown for each species. Applies to those snags whose age is less than or equal to Upper age (yrs) of snag light extinction class 1. Expressed as a fraction between 0 and 1. If your run does not work with snags, you can ignore this. Otherwise, a value must be provided for all species. 
Snag Age Class 2 Light Extinction Coefficient (01)  Fraction of light transmitted through the snag tree crown for each species. Applies to those snags whose age is greater than Upper age (yrs) of snag light extinction class 1, but is less than or equal to Upper age (yrs) of snag light extinction class 2. Expressed as a fraction between 0 and 1. If your run does not work with snags, you can ignore this. Otherwise, a value must be provided for all species. 
Snag Age Class 3 Light Extinction Coefficient (01)  Fraction of light transmitted through the snag tree crown for each species. Applies to those snags whose age is greater than Upper age (yrs) of snag light extinction class 2. Expressed as a fraction between 0 and 1. If your run does not work with snags, you can ignore this. Otherwise, a value must be provided for all species. 
Upper Age (Yrs) of Snag Light Extinction Class 1  The upper age limit, in years, defining the first age class of snag light extinction. Snags with an age less than or equal to this age have a light extinction coefficient matching Snag age class 1 light extinction coefficient. If your run does not work with snags, you can ignore this. 
Upper Age (Yrs) of Snag Light Extinction Class 2  The upper age limit, in years, defining the second age class of snag light extinction. Snags with an age greater than the upper limit for size class 1, but less than or equal to this age, have a light extinction coefficient matching Snag age class 2 light extinction coefficient. Snags with an age greater than this value are in age class three. If your run does not work with snags, you can ignore this. 