肖郎平 貴州日報(bào)記者

對自然哲學(xué)感興趣的人，或許應(yīng)該細(xì)心品味一下貴陽的兩條環(huán)城林帶。在這里，人們能感受到道家自然無為的哲學(xué)，也能窺探到生態(tài)系統(tǒng)在人的有為和自然的無為之間實(shí)現(xiàn)演替的秘密。

在貴陽市環(huán)城林帶，你也能發(fā)現(xiàn)中國生態(tài)觀念發(fā)生了巨大的轉(zhuǎn)折。半個世紀(jì)以前，人們著力于解決增加樹木的數(shù)量關(guān)系，現(xiàn)在開始和大自然一起合作改善品種的質(zhì)量關(guān)系。

始于1958年的“大躍進(jìn)”是一場大自然的浩劫，放眼全國，無數(shù)森林在那一年迅速從地平線上消失。但在貴陽市，順海、都溪、長坡林等近百個大大小小的林場卻在這一年誕生，逆向前進(jìn)，承擔(dān)起了綠化城郊的使命。

那時候，誰也不會想到，這些林場會慢慢生長成一個綠色的環(huán)。上世紀(jì)七八十年代，人們坐飛機(jī)俯瞰發(fā)現(xiàn)，貴陽被一圈綠色的森林所環(huán)繞，“環(huán)城林帶”的概念由此而生。這個“環(huán)”從黔靈山公園開始，經(jīng)鹿沖關(guān)森林公園、省植物園、順海林場到湯巴關(guān)、鳳凰山林場、孟關(guān)林場，再到花溪公園、麥坪、石板附近的森林，連接小車河濕地公園、云貴大山，最后又銜接黔靈山公園。這個“環(huán)”構(gòu)成了貴陽第一環(huán)城林帶。

第一環(huán)城林帶長70公里、寬1至7公里，總面積近30萬畝。曾經(jīng)，它默立于城市邊際，就像是瘦弱的舊城市身上那搖搖晃晃的綠色裙擺，伴隨著貴陽城區(qū)面積擴(kuò)大了約 23倍，如今則更像是緊扣在膨脹的新城市頭上的碧玉發(fā)冠。

貴陽市林業(yè)高級工程師張德門說，2001年，貴陽市做出建成“林城”的決定，營造第二環(huán)城林帶。2006年，“二環(huán)林帶”建成，前來實(shí)地考察、檢查的中國林科院 7位專家表示，作為西部不發(fā)達(dá)地區(qū)，花費(fèi)幾億元植樹造林，讓人“沒想到”，實(shí)在“了不起”！

二十年前國家實(shí)施天然林資源保護(hù)工程，對天然林資源禁止商品性采伐，順海、長坡嶺等林場紛紛建設(shè)成為森林公園。2004年，貴陽成為全國首個“國家森林城市”。

截至 2015年，貴陽環(huán)城林帶林地面積為 239.05萬畝，占全市林地面積的43.37%，它讓貴陽市有了“城在林中、林在城中、四季常青、人居舒適”的城市面貌。人們在解釋森林這個詞的時候，總是說雙木為林、三木為森，但事實(shí)上，森林不只是數(shù)量上的樹木堆積，還應(yīng)該在品種上形成立體系統(tǒng)。由眾多胸徑40-50厘米樹木構(gòu)成的環(huán)城林帶，是城市的綠色氧吧，更是市民健身休閑的好去處，但不可否認(rèn)的是，它仍然有著大面積人工造林的缺點(diǎn)，那就是林相單一，生態(tài)效益差。

為了改變這一狀況，順海林場從上世紀(jì) 90年代開始對部分林地進(jìn)行改造，到2013年底共改造近萬畝，主要營造的是防護(hù)林和生態(tài)景觀林。如西眾環(huán)狀采伐更新和爛壩林區(qū)塊狀采伐更新，均采取針闊林混交的方式，調(diào)整林分結(jié)構(gòu)。

盡管如此，順海林場目前 90% 的樹種仍然是馬尾松。順海林場林政科科長賴文廣希望，在未來一二十年里，將逐漸從森林的中下部改造，適當(dāng)補(bǔ)種適生的本土闊葉樹種。因?yàn)樯值闹邢虏克翖l件更好，有利于闊葉樹的生長，同時可以避免從森林頂部改造帶來的水土流失問題。

除了人為干預(yù)之外，大自然的生態(tài)演化也正在發(fā)揮作用。環(huán)城林帶的變化，給貴州省政協(xié)經(jīng)濟(jì)委員會主任、原貴州省林業(yè)廳廳長金小麒留下了深刻的印象。他說，五十年代設(shè)立林場時，環(huán)境退化嚴(yán)重，裸露干旱，而大部分闊葉樹早期喜陰，在這樣的環(huán)境下難以成活，因此只能栽種喜光的馬尾松等樹種，伴隨著馬尾松等樹木的生長，闊葉樹的成活要求被滿足，此時闊葉樹開始生長，但成林后的闊葉樹遮住光線，反過來阻礙了喜光的馬尾松幼苗生長。金小麒預(yù)計(jì)，環(huán)城林帶以后都會變成闊葉林，他說，環(huán)城林帶的變化生動地詮釋了什么是生態(tài)系統(tǒng)，“先是環(huán)境改變?nèi)郝?，然后是群落改變環(huán)境，從而完成環(huán)境演變?！?/p>

有心造林，這些樹木順其自然成為環(huán)繞城市的森林，又在無意間成就了諸多森林公園；人為改造著森林，與此同時，生態(tài)又進(jìn)行著自動演替。在這里，相信你會對中國自然哲學(xué)更有一番體會。

One Forest Belt: Natural Philosophy of Forestation

Xiao Langping Guizhou Daily Reporter

Those who are interested natural philosophy, could pay some attention to savor the two forest belts in Guiyang city. Here, people will not only feel the natural inaction of Taoism, but also can take a glance at how ecosystem evolves between man’s activity and nature’s inactivity.

Within Guiyang’s forest belts you can also discover the drastic change of eco concept in people’s mind. Half a century ago, people’s attention was focused on adding up the number of the trees whereas now, they have begun to work together with Nature to promote quality of the varieties.

The "Great Leap Forward" movement, which began in 1958, was a catastrophe of nature, and across the country, countless forests were rapidly disappearing from the horizon that year. But in Guiyang, Shunhai, Duxi, Changpolin and so on,nearly hundreds of large and small forest farms were born in this year, assuming the mission of greening the suburbs against the surge of havoc.

At that time, no one would have thought that these forest farms would slowly grow into a green ring. In the 1970s and 1980 s, people who were flying over discovered that Guiyang was surrounded by a circle of green forests, and the concept of "ring forest belt" was born. This "ring" starts from the Guizhou Qianling Mountain Park,through Lu Chong Guan Forest Park, Provincial Botanical Garden, Shun Hai Forest Farm to Tang Ba Guan, Phoenix Mountain Forest, Meng Guan Forest, and then to the forests nearby Huaxi Park, Maiping, Shiban, connecting Xiao Che River Wetland Park, the mountain crossing Yuannan and Guizhou, and finally converges to Guizhou Qianling Mountain Park. This "ring" constitutes the finest city forest belt in Guiyang.

The first ring belt is 70 km long and 1 to 7 km wide, with a total area of nearly 300,000 acres. Once, it stood silently on the edge of the city, as if a rickety green skirt on the scraggy old city. With the expansion of Guiyang's urban area by about 23 times, now it's more like a Jasper crown on the head of a new, bloated city.

Zhang Demen, senior forestry engineer in Guiyang, said that in 2001, Guiyang made the decision to create the second ring forest to build a "Forest City".In 2006, "the Second Ring forest" was completed, and upon site visiting, 7 experts of the Chinese Academy of Forestry said, a western underdeveloped area spending hundreds of millions of yuan afforestation was "unexpected", and really "astonishing"!

20 years ago, when the National Natural Forest Resources Protection Project was initiated , to prohibit the commercial logging of the natural forest resources,Shunhai, Changpoling and other forest farms were built into a forestry park. In the year 2004, Guiyang became the first "National Forest City" in China.

As of 2015, the city-ring forest felt area of Guiyang achieved 2.3905 million acres, accounting for 43.37% of the urban forest area, which let Guiyang possessed the appearance of "city in the forest, forest in the city, four-season evergreen, comfortable living environment".

When people come to the interpretation of the word “forest”, it is always said that “double trees for woods, three trees for forest”, but in fact, the forest is not only the accumulation of tree numbers, but it should also form a three-dimensional system on the species. Composed of a large number of trees with a trunk diameter of 40～50 cm, the Ring belt of the city is a green oxygen bar, as well as a good place for the public fitness and leisure. However,it is undeniable that it still has the disadvantage of large-scale artificial forestation: pine monoculture, and poor ecological benefits.

In order to change this situation, Shunhai Forest Farm began to transform some of the woodlands in 1990s, and till the end of 2013 a total of nearly ten thousand mu was finished, mainly in shelter forests and ecological landscape forests. The forest structure is adjusted by the way of mixing coniferous and broad-leaved forest, such as circular felling renewal in Xizhong and the block felling renewal in the Lanba forest area.

Still, 90% of the trees at Shunhai Farm are Masson pine. Lai Wenguang, forest section chief of Shunhai Forest Farm hopes that in the next 10 to 20 years,transformation should be made from the middle and lower parts of the forest,with appropriate native hardwood species replanted. The water and soil conditions in the middle and lower parts of the forest are conducive to the growth of broad-leaved trees, while avoiding the problem of soil erosion caused by the transformation from the top of the forest.

In addition to human intervention, the ecological evolution of nature is also playing a role. The change of the forest belt around the city has left a deep impression on Jin Xiaoqi, director of the Economic Committee of the Guizhou Provincial Political Consultative Conference and former director of the Guizhou Provincial Department of Forestry. He said that when setting up a forestry site in the 1950s, the environment was seriously degraded and there was an open drought. Most of the broad-leaved trees are shade demanding in early time, and it is difficult to survive in such an environment. Therefore, only species such as Masson pine which is pleasing to light can be planted. With the growth of trees such as Masson pine, the survival requirements of broad-leaved trees are met. At this time, broad-leaved trees begin to grow, but the broad-leaved trees in the forest cover the light, which in turn hinders the growth of Masson pine seedlings. Jin Xiaoqi expects that the forest belt around the city will become a broad-leaved forest. He said that the changes in the belt around the city vividly explain what an ecosystem is. "First the environment changes the community, then the community changes the environment, and thus completes the environmental evolution."

With the intention of afforestation, these trees naturally become forests that surround the city, and they have inadvertently created many forest parks;people transform the forests, and at the same time, the ecology is undergoing automatic succession. Here, I believe you will have a better understanding of Chinese natural philosophy.