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Directional Variation in Little-leaf Linden (Tilia cordata Mill.) Crown Development


3.57575
Article
1992
Leaves on the north side of little-leaf linden‡ (Tilia Cordata Mill.) trees are well adapted to the relatively moderate environment resulting from the southern position of the sun in the northern hemisphere sky. Because the sun rises north of east, the maximum sunlight level on the north side of the tree occurs in the morning, at approximately 0800 hrs Central Standard Time. On the north side, peak assimilation rate per unit leaf area (A) was higher, occurred earlier in the day, and at lower light levels than on the south side. Total assimilation per unit leaf area (Ata) was similar on both sides, but there was 15 percent greater leaf surface area on the north side, resulting in higher calculated total daily assimilation (Atd) on the north side of the crown for sunny days. In the lower third of the crown, which is the most highly shaded portion of the north side, the Atd was 58 percent greater on the north side. Under cloudy skies, low light reduced A on the south side, but not on the north side. On hot days (maximum temperature ⩾32°C) Ata was decreased on the south side and increased on the more shaded north side. Greater assimilate production on the north side over the entire growing season, particularly on cloudy or partly cloudy days (62 percent of all days in the growing season in the Midwest) and hot days, may be at least partially responsible for previously reported greater growth on the north side of trees.

16, 243-252
Arboricultural Journal (published by)
This object is either not yet digitized or not digitally available. To learn how to gain access, please contact the Sterling Morton Library at library@mortonarb.org or (630) 719-2429.
Copyright statement:

Copyright restrictions applying to use or reproduction of this image are available from the Sterling Morton Library, The Morton Arboretum. For more information, please visit our ABOUT section or complete and submit this form.