« Green China Rose | Main | Sunflower center »
July 04, 2006
The Sycamore(s) Falling!
Sycamore leaf and fruit
L.A. Street Service teams were working the holiday, chopping up fallen sycamore limbs all around our neighborhood.
Why so many limbs down? An internet search produced the following theories:
Two common summer-time branch fractures are “fruit weight failure” and “summer branch drop.”
1. Fruit weight failure can be due to weight of the fruit. Some pine trees will break due to the weight of cones and foliage.
2. Abundant seasonal moisture may cause the weight of water in the tree to overcome the strength and number of medulary rays. In this case, the problem is lack of rays in the cellulose/lignin/hemicellulose structure.
3. Branch wood looses elasticity as it looses moisture and that lack of elasticity can lead to fracture, or delamination and then fracture. Stress moves to strain moves to failure.
4. Irrigation when the temperatures are above 90F after a dry spell in the mid to late growing season will cause the tree to absorb water then close down stomates as the temperature rises to conserve moisture. The result is high water weight (bloated trees?) and limb fracture. This is most common after a dry period, in which wood shrinks and fibers pop, causing microfissures and loss of strength.
Sycamore is fairly strong wood, so we the non-expert armchair tree surgeons at Downtown Tomatoes, who have been whining the last month about high temperatures and lack of H20, and irrigating lavishly -- DRY + HOT + WATER -- vote for theory number 4.
Posted by Sue at July 4, 2006 09:28 PM
Trackback Pings
TrackBack URL for this entry:
http://www.downtowntomatoes.com/mt/mt-tb.cgi/133