Mature quiver trees flower and disperse seeds every year. However, climatic conditions are not always conducive to germination so a crop of youngsters may only appear and survive every few years when the conditions are ideal. Conservation biologist Wendy Foden found a strong correlation between leaf-dropping and the mortality rate throughout the quiver tree communities in the desert region of the Knersvlakte.
Both factors followed latitudinal gradients that indicated greater die-back was occurring the further north the team went in the aloe's distribution. When the trees started shedding leaves, it meant they were on their way out. It also showed that long-term stress was the likely cause of death.
Sometimes an amputated branch would send out a shoot below the stump and begin growing again - but this only happened when a rare time of abundance saved the tree from drought. It appeared that neither disease nor predation could explain the damage and death of this iconic desert aloe.