Definition
To topple is to to turn or cause to turn from a vertical or horizontal position.
Etymology. 1590, "tumble down," earlier "to tumble or roll about" (1542), from a verb derived from top (1) + freq. suffix -le.
Discussion
Toppling usually occurs where plant have compromised root systems due to any number of factors, including plant pathognes and insect parasites, poor soil conditions or poor drainage, and high winds.