Fig. 1. Diurnal change in mean solar irradiance ( 0.35–2.5 µm) in control (unshaded), and loblolly and shortleaf pine microsites. Data were collected from 0500 to 1930 h (CST) on 1 to 15 June 2000 and 2001. Prediction equations for solar reception were Y = –0.045T – 0.013T² + 6.60 x 10^–3T³ – 5.57 x 10^–4T⁴ + 1.33 x 10^–5T⁵, R² = 0.99; Y = 0.024T – 0.028T² + 6.38 x 10^–3T³ – 4.58 x 10^–4T⁴ + 1.03 x 10^–5T⁵, R² = 0.96; Y = 0.018T – 0.034T² + 8.61 x 10^–3T³ – 6.47 x 10^–4T⁴ + 1.50 x 10^–5T⁵, R² = 0.97 for control, loblolly pine, and shortleaf pine, respectively. T = time (h), CST. Vertical bar indicates LSD (P = 0.05).