The store of pollen paints a picture of the plains of 13,000 years ago,
花粉纷纷扬扬聚集，勾画出1300年前的大平原。
a picture that looks very different from the open prairie grassland of today.
同今日辽阔的草原相比，当时的景象则截然不同。
But why did this region look so different back then?
但为何差别如此之大?
The ice sheets to the north, although retreating 13,000 years ago, still dominated the climate here.
尽管1300年来冰层不断北移，但该区仍属冰原性气候。
It was much milder and wetter than today, ideal conditions for woodland to flourish.
气候甚至更为湿润，也更利于林木茂密生长。
This is how much of the northern plains must have looked when the first people arrived.
这也许是第一批来到此处的人类在北方草原看到的景象。
Not open prairies as it is now, but a parkland of trees and grassy meadows.
当时这里并不是平原，而是稀树高原和茂密的田野。
This is a relic of those times. The Osage orange.
这是桑橙树，是一种经历过以前那种气候，一直存活至今的树木。
Every autumn it produces these enormous fruits, huge numbers of them, more the size of great fruits than mere oranges.
每年秋季这种树就会结出大量果实，而且果实的个头比普通的橘子要大很多。
But there's no animal alive today that's big enough to pick and eat them, so this bump of crop just rots.
但现今生存的动物身躯不够庞大，无法采摘和食用这些果实，所以这些果实只能烂掉。
The Osage orange glory days are long gone.
桑橙树繁盛的时代已经过去。
But its harvest was once an annual feast for many ice age animals, including mammoths.
曾经每年桑橙树收获果实的季节，对冰河世纪许多动物来说是一场盛宴。
Fruit must have been a real treat for these grass eaters.
比如说猛犸象。对猛犸象这样的食草动物来说，水果无疑是美食。
