曾在“树木可以为人类做什么?”一文中介绍过树木对人类的多种好处， 也提出了一个问题，为什么保育人士要谴责在亚马逊森林砍伐热带雨林，改种棕榈树的人？ 两者都是树。应该都能或多或少地做出大多数树木为人类做的好事，对吧？为什么我们不爱为我们生产生物燃油的棕榈树？
常听到我们的自然环境需要“物种多样化”。但是，我们必须明白“物种多样化”并不意味着我们尽可能有多少物种便要多少物种。我们应该说，我们只需要属于该地区的原生物种多样化， 不需要外来的物种！因为，不同地方的自然生态是完全不一样的，是独一无二的。经过了千百万年的发展， 磨合，所有在那里的生物已经 达到了一种非常微妙的， 脆弱的平衡，一种很容易被破坏，很难修复的平衡。在该生态系统中任何物种的 灭绝，都可能导致另一种物种的消失，甚至可能产生骨牌效应， 导致整个生态系统的崩溃。这就是我们必须保护原生物种的原因。
你可知道许多植物是会通过本身制造的化学品或其他防御武装来保护自己？有听过毛利人使用卡瓦卡瓦（kawakawa） 叶来治疗伤口感染，喉咙痛等吗？在树林里的我们看到的卡瓦卡瓦叶，很多都有虫口。毛利人就特别爱选这些有虫口的叶子作药用，因为毛利人知道，那棵植物在被许多毛毛虫攻击之后，已经在叶子里分泌了一些特殊的抗体，用来治病会更有功效。叶子的抗体可以阻止毛毛虫进一步的袭击，该毛毛虫是该地区的原生昆虫， 它能适应改变，能与装备了的树木和谐共存。经过漫长岁月，在特定地区里，所有的生物都适应了周围环境。如果这些原生树木被砍伐并用一些外来树木替代，原生的昆虫从未遇过外来的树木， 适应不了，许多便会死亡，会灭绝。还有依靠原生树木生活的其他动物， 附在原生树木上的真菌，细菌，地衣等， 也会因原生树木的消失，可能也 一并丧亡。
当然，昆虫是许多雀鸟的主食， 鸟类需要昆虫， 传播花粉需要昆虫， 土壤需要细菌和真菌等帮助本地植物生长，该地的自然生态需要原生动物去保持生态平衡， 所有原生生物， 都在本土生态系统中发挥非常重要的作用。因此，当原生树木消失时，连锁反应， 整个生态系统将会陷入大混乱。
新西兰贝壳杉是新西兰的原生树木，不少贝壳杉正 因贝壳杉枯死病而死亡。在贝壳杉周围有它一种非常特殊的生态系统。正如上面所说，贝壳杉的消失，可能导致该生态系统的崩溃， 进而可能导致另一个生态系统的扰乱或另一个生态系统的崩溃。最终会发生什么 ？没人知道。当我们发现问题的时候，可能为时已晚。所以，现在就让我们来帮忙吧！只要在进，出贝壳杉森林时清洁我们的鞋子，走在指定的山径上， 把消息传播给亲友让大家一起来帮忙， 就是这样简单！
Why do we need to Protect our native trees? Estella Lee
In my article “What trees can do for human being?” I have mentioned what good things trees can do to human beings. I also raised the question why conservationist condemned those who cut down rainforest in the Amazon jungle to plant palm trees. Both are trees. Both should be able to do more or less the same good things most tree can do for us, right? Why shouldn’t we have palm trees that produce biofuel for us as well ?
Often, we heard that we need biodiversity in our natural environment. However, we must understand “biodiversity” does not mean we need as many species as possible. We should say, we only need the biodiversity of the living creatures which belong to that particular area. Not anything outside that area. We must understand that the natural eco system of different places are different and unique to that area. It has evolved for millions of years and has come up to some kind of very subtle and fragile balance amount all the living creatures there. It is easy to upset and hard to restore. Extinction of any kind of species may lead to extinction of another. Like the poker cards falling on one another. It can lead to a collapse of the whole eco system. This is why we have to protect indigenous species.
We may not know that plants can protect themselves by arming themselves with chemicals and other defences. We may have heard that Maori use Kawakawa leaves for medicinal use, for infection, for sore throat, etc. When we see the kawakawa leaves in the forest, many have insect holes in them. Maori will purposely pick the leaves with many holes because the maori understand, that plant, after been attacked by many caterpillars, has secreted some kind of special chemicals in its leaves. That chemical can stop further caterpillar attack and the leaves are better for medicinal use. Native insects also has adapted to it and allow them to cope and survive with the native trees’ chemicals and other defences that those trees equip themselves with. Eco balance came upon particular area after many, many years, all living creatures have got the adaptation to their surroundings. If these native trees are cut down and replaces with some exotic trees, the native insects may not have evolved to feed on these trees that they have never encountered before. They may die. So are the animals that rely on the native trees for their living. The fungus, bacteria, lichen that live with the native trees. So, they may all die and/or extinct.
UK Survey has found that their native Oaks harbour 284 insect species and 324 Lichens species in the UK. . But horse chestnut, introduced from the Balkans, hosts only four kind of insects.
Of course, many birds live on insects. When the insects disappear, birds will disappear too. Many native plants need the insects for pollination. Soil need the native bacteria and fugus to help other native plants grow. The eco system needs the native animals to keep the balance. They all play a very important role in the eco system. When the native trees disappear, the whole eco system will be upset.
NZ Kauri is NZ’s native tree. Many are dying of Kauri Die Back. We also know that there is a very special eco system around the kauris. As mentioned above, the disappearance of native trees, in this case is kauri may lead to the collapse of that eco system. This upset may lead to upset of another eco system and/or collapse of another eco system, on and on. What eventually will happen? Nobody knows. By the time we find out what is wrong, it may be too late. So, let’s do it now ! Just to clean our shoes when going in and out of the kauri forest, stick to the track and spread the news. It’s just this simple !!!
Some of the information in the article are sourced from the website underneath