On Jul 14, 9:13*pm, "Kate Morgan" wrote:
I am aware that these trees are poison to horses etc but I also heard that
the roots can contaminate the ground and grass around them, *also poison are
the bits falling from the trees. Any thoughts anyone?

kate

Many non-deciduous trees keep the forest floor clear by use of toxins
in fallen leaves and by excluding all light. It's all part of nature's
chemical warfare. Their own seedlings are immune to the toxins. If
a tree should fall, letting in the light, the seedlings spring to life
in an incredible fashion. Normally the toxins break down. in a few
months if not replenished.
Rhodedenron is one of the most toxic.
Coniferous trees are one of the oldest on earth, their chemical
warfare
factories are very advanced.

Horses originated in the steppe (open grassland) and have poor
resistance to the forest toxins. Pigs have always been forest
dwellers and are more resistant to these toxins. Totally resistant to
some.