This is the tree line, the first place on our journey with sufficient warmth and liquid water to enable a tree to grow。

 

Surviving here is so crushingly difficult that it can take hundreds of years for a seedling to grow into a stunted shrub.

 

But even small trees can provide / cover for a predator

 

Wolves, these in northern Canada are the largest and most powerful in the world and they are setting out to hunt

 

The pack is 25 strong, a sign that the prey they are seeking is formidable

 

These bison/ are even bigger than their southern cousins and the largest land animals in North America

 

For generations, wolves and bison/ here have been shaped by their battles for the each other, making each the most impressive of its kind

 

The bison/ would not stay in long among the trees, they are not safe here

 

The wolves are closing in, but their chance of ambushing the bison/ in the woods has passed, their prey are now in the open and group together for safety.

 

The wolves will need to work as a team, exact to make a kill.

 

They circle the herd, try to unsettle it and split it up

 

But the bison/ are / armed and dangerous, they will be safe as long as they stick together.

 

The wolves, up their game, hurrying the herd, a ploy to trigger a stampede and split away one of the smaller ones