The causes of the UK's current position are complex and range from outdated perceptions of productive forestry to the decimation of trees by grey squirrels.

英国目前处于这种状况的原因复杂，范围从对生产性林业的过时看法到灰松鼠对树木的大量破坏。

The grey squirrel was introduced into Britain from North America.

【introduce】灰松鼠是由北美引入英国的。

Good idea. Some for little grey squirrel and little redwood fox and daughter and little white Ah, there.

好主意 一些给小灰松鼠 小红木狐狸 女儿和小白种人啊 在那儿。

Traditionally, red squirrels lived in the UK, but then grey squirrels came from America, and because of them most red squirrels have died out.

传统上，红松鼠生活在英国，但后来灰松鼠来自美国，因此大多数红松鼠已经灭绝。

From American grey squirrels displacing European red ones, to Japanese knotweed displacing just about everything everywhere, their purported negative effects on nature are there for all to see.

从美州灰松鼠取代欧洲红松鼠，到日本虎杖取代英国几乎所有本土植物，外来物种对自然造成的负面影响是有目共睹的。