一条林带：造林的自然哲学

肖郎平 贵州日报记者

对自然哲学感兴趣的人，或许应该细心品味一下贵阳的两条环城林带。在这里，人们能感受到道家自然无为的哲学，也能窥探到生态系统在人的有为和自然的无为之间实现演替的秘密。

在贵阳市环城林带，你也能发现中国生态观念发生了巨大的转折。半个世纪以前，人们着力于解决增加树木的数量关系，现在开始和大自然一起合作改善品种的质量关系。

始于1958年的“大跃进”是一场大自然的浩劫，放眼全国，无数森林在那一年迅速从地平线上消失。但在贵阳市，顺海、都溪、长坡林等近百个大大小小的林场却在这一年诞生，逆向前进，承担起了绿化城郊的使命。

那时候，谁也不会想到，这些林场会慢慢生长成一个绿色的环。上世纪七八十年代，人们坐飞机俯瞰发现，贵阳被一圈绿色的森林所环绕，“环城林带”的概念由此而生。这个“环”从黔灵山公园开始，经鹿冲关森林公园、省植物园、顺海林场到汤巴关、凤凰山林场、孟关林场，再到花溪公园、麦坪、石板附近的森林，连接小车河湿地公园、云贵大山，最后又衔接黔灵山公园。这个“环”构成了贵阳第一环城林带。

第一环城林带长70公里、宽1至7公里，总面积近30万亩。曾经，它默立于城市边际，就像是瘦弱的旧城市身上那摇摇晃晃的绿色裙摆，伴随着贵阳城区面积扩大了约 23倍，如今则更像是紧扣在膨胀的新城市头上的碧玉发冠。

贵阳市林业高级工程师张德门说，2001年，贵阳市做出建成“林城”的决定，营造第二环城林带。2006年，“二环林带”建成，前来实地考察、检查的中国林科院 7位专家表示，作为西部不发达地区，花费几亿元植树造林，让人“没想到”，实在“了不起”！

二十年前国家实施天然林资源保护工程，对天然林资源禁止商品性采伐，顺海、长坡岭等林场纷纷建设成为森林公园。2004年，贵阳成为全国首个“国家森林城市”。

截至 2015年，贵阳环城林带林地面积为 239.05万亩，占全市林地面积的43.37%，它让贵阳市有了“城在林中、林在城中、四季常青、人居舒适”的城市面貌。人们在解释森林这个词的时候，总是说双木为林、三木为森，但事实上，森林不只是数量上的树木堆积，还应该在品种上形成立体系统。由众多胸径40-50厘米树木构成的环城林带，是城市的绿色氧吧，更是市民健身休闲的好去处，但不可否认的是，它仍然有着大面积人工造林的缺点，那就是林相单一，生态效益差。

为了改变这一状况，顺海林场从上世纪 90年代开始对部分林地进行改造，到2013年底共改造近万亩，主要营造的是防护林和生态景观林。如西众环状采伐更新和烂坝林区块状采伐更新，均采取针阔林混交的方式，调整林分结构。

尽管如此，顺海林场目前 90% 的树种仍然是马尾松。顺海林场林政科科长赖文广希望，在未来一二十年里，将逐渐从森林的中下部改造，适当补种适生的本土阔叶树种。因为森林的中下部水土条件更好，有利于阔叶树的生长，同时可以避免从森林顶部改造带来的水土流失问题。

除了人为干预之外，大自然的生态演化也正在发挥作用。环城林带的变化，给贵州省政协经济委员会主任、原贵州省林业厅厅长金小麒留下了深刻的印象。他说，五十年代设立林场时，环境退化严重，裸露干旱，而大部分阔叶树早期喜阴，在这样的环境下难以成活，因此只能栽种喜光的马尾松等树种，伴随着马尾松等树木的生长，阔叶树的成活要求被满足，此时阔叶树开始生长，但成林后的阔叶树遮住光线，反过来阻碍了喜光的马尾松幼苗生长。金小麒预计，环城林带以后都会变成阔叶林，他说，环城林带的变化生动地诠释了什么是生态系统，“先是环境改变群落，然后是群落改变环境，从而完成环境演变。”

有心造林，这些树木顺其自然成为环绕城市的森林，又在无意间成就了诸多森林公园；人为改造着森林，与此同时，生态又进行着自动演替。在这里，相信你会对中国自然哲学更有一番体会。

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.