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

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.

Thank you Chris and Harry, both answers useful.

kate

I know it's widely believed that a range of trees and other plants put toxins into the soil to reduce competition. But I'd love to see a scientific reference to this. Googling gives me references to the toxic effects of walnut but not much else.

I suspect the lack of growth in a conifer forest could be explained by deep shade and drying out of soil. Even in deciduous woods there isn't much growing in the summer - most of the understorey growth is in the spring when there is no leaf cover.

My own experience of 4 25ft leylandiis is that a bay tree, ivy and a Vibunum bodnantense are growing perfectly well amongst them, and that corydalis and daffodils managed for about 10 years. In other words, whay I am experiencing is much more like the effects of dryness and shade rather than soil toxicity.

On Jul 16, 2:14*pm, kay wrote:
Kate Morgan;930267 Wrote:

Thank you Chris and Harry, both answers useful.

I know it's widely believed that a range of trees and other plants put
toxins into the soil to reduce competition. But I'd love to see a
scientific reference to this. Googling gives me references to the toxic
effects of walnut but not much else.

I suspect the lack of growth in a conifer forest could be explained by
deep shade and drying out of soil. Even in deciduous woods there isn't
much growing in the summer - most of the understorey growth is in the
spring when there is no leaf cover.

My own experience of 4 25ft leylandiis is that a bay tree, ivy and a
Vibunum bodnantense are growing perfectly well amongst them, and that
corydalis and daffodils managed for about 10 years. In other words, whay
I am experiencing is much more like the effects of dryness and shade
rather than soil toxicity.

--
kay

Bit here on the topic. HEAVY..........
http://idosi.org/aejsr/5(4)10/5.pdf