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Today I'm going to talk about the eucalyptus tree.
今天我要讲的是桉树。
This is a very common tree here in Australia, where it's also sometimes called the gum tree.
这是一种在澳大利亚非常常见的树，在那里它有时也被称为橡胶树。
First I'm going to talk about why it's important, then I'm going to describe some problems it faces at present.
首先，我要谈一谈它很重要的原因，然后我要描述它目前所面临的一些问题。
Right, well the eucalyptus tree is an important tree for lots of reasons.
没错，桉树是一种重要的树木，原因有很多。
For example, it gives shelter to creatures like birds and bats, and these and other species also depend on it for food, particularly the nectar from its flowers.
例如，它为鸟类和蝙蝠等生物提供庇护，这些物种和其他物种也从它身上获取食物，尤其是它的花蜜。
So it supports biodiversity.
因此，它支持生物多样性。
It's useful to us humans too, because we can kill germs with a disinfectant made from oil extracted from eucalyptus leaves.
它对我们人类也很有用，因为我们可以用从桉树叶中提取的油制成的消毒剂杀死细菌。
The eucalyptus grows all over Australia and the trees can live for up to four hundred years.
桉树生长在澳大利亚各地，这些树可以存活长达四百年。
So it's alarming that all across the country, numbers of eucalyptus are falling because the trees are dying off prematurely.
但令人担忧的是，由于树木过早死亡，澳大利亚各地的桉树数量都在下降。
So what are the reasons for this?
那么，造成这种情况的原因是什么？
One possible reason is disease.
一个可能的原因是疾病。
As far back as the 1970s the trees started getting a disease called Mundulla Yellows.
早在20世纪70年代，桉树就开始患上一种名为蒙杜拉黄化的疾病。
The trees' leaves would gradually turn yellow, then the tree would die.
树的叶子会逐渐变黄，然后树就会死亡。
It wasn't until 2004 that they found the cause of the problem was lime, or calcium hydroxide to give it its proper chemical name, which was being used in the construction of roads.
直到2004年，他们才发现问题的原因是石灰，它的化学名称是氢氧化钙，当时人们用石灰铺设道路。
The lime was being washed away into the ground and affecting the roots of the eucalyptus trees nearby.
石灰被冲进了地下，影响了附近桉树的根部。
What it was doing was preventing the trees from sucking up the iron they needed for healthy growth.
它阻止了桉树吸收它们健康生长所需的铁。
When this was injected back into the affected trees, they immediately recovered.
当给受影响的桉树注射铁时，它们立即恢复了健康。
But this problem only affected a relatively small number of trees.
但这个问题只影响了相对较少的树木。
By 2000, huge numbers of eucalyptus were dying along Australia's East Coast, of a disease known as Bell-miner Associated Die-back.
到2000年，澳大利亚东海岸有大量桉树死于矿吸蜜鸟枯梢病。
The bell-miner is a bird, and the disease seems to be common where there are high populations of bell-miners.
矿吸蜜鸟是一种鸟，这种疾病似乎在矿吸蜜鸟数量较多的地方很常见。
Again it's the leaves of the trees that are affected.
同样，受影响的是桉树的叶子。
What happens is that insects settle on the leaves and eat their way round them, destroying them as they go, and at the same time they secrete a solution which has sugar in it.
昆虫停留在树叶上，在树叶周围觅食，它们边移动边破坏树叶，同时它们分泌一种含有糖的溶液。
The bell miner birds really like this solution, and in order to get as much as possible, they keep away other creatures that might try to get it.
矿吸蜜鸟很喜欢这种溶液，为了尽可能多地获得它，它们会阻止其他可能试图获得它的生物靠近桉树。
So these birds and insects flourish at the expense of other species, and eventually so much damage is done to the leaves that the tree dies.
因此，这种鸟类和昆虫以牺牲其他物种为代价茁壮成长，最终对桉树叶造成巨大的损害，导致树木死亡。
