淺山區(qū)的城市化

“淺山區(qū)”并非是嚴(yán)格意義上的一種地理單元或地貌類型，它是對位于深山與平原過渡地帶上的山地區(qū)域的一種寬泛性稱謂，可包括低山、丘陵、臺地和沖溝等多種地形特征。

二次世界大戰(zhàn)后，歐美發(fā)達國家和一些新興發(fā)展中國家進入快速城市化進程，人口聚集導(dǎo)致適宜建設(shè)的平地資源日益短缺，越來越多的淺山地帶被轉(zhuǎn)化為城市建設(shè)用地，成為都市化進程中的市民居住或休閑的空間。

中國在快速城市化過程中，淺山地帶也受到越來越多的關(guān)注。最近我看到一則房地產(chǎn)廣告，說縱觀全球，凡淺山地帶都擁有絕佳的居住環(huán)境，這里往往是房價最高的區(qū)域，對這一點我深信不疑。中國是一個山地國家，許多城市位于山前平原或山間盆地，如果交通方便，出城市不遠就到了背依群山、面朝田園和城市、風(fēng)景優(yōu)美的淺山地帶，受各種利益的驅(qū)動，城市發(fā)展必然會逐步深入到淺山區(qū)。實際上在世界各地的快速城市化過程中，人類的各種大規(guī)模建造都曾經(jīng)或已經(jīng)開始向城市周邊的淺山區(qū)擴張和蔓延。

過去30年來中國的城市化率平均每年增長約1%左右，在未來的一段時間內(nèi)仍將保持相近的增長率，而城市化率每增加1個百分點，中國至少要有2 000km2的各類土地轉(zhuǎn)變?yōu)槌鞘薪ㄔO(shè)用地，這其中就包括淺山區(qū)。

然而，淺山區(qū)的開發(fā)建設(shè)卻引起我深深的憂慮，因為其一，淺山是山地生態(tài)系統(tǒng)與平原生態(tài)系統(tǒng)相互交錯的區(qū)域，是山岳與平原之間重要的生態(tài)緩沖區(qū)，也是山前平原最重要的水源涵養(yǎng)地和地下水回補區(qū)，管理好淺山地帶的生態(tài)環(huán)境對于維護整個城市健康的生態(tài)系統(tǒng)至關(guān)重要。大規(guī)模的城市建設(shè)蔓延到淺山區(qū)，如果沒有深入的研究、合理的規(guī)劃、恰當(dāng)?shù)慕ㄔO(shè)，極有可能威脅到這一極為敏感地帶的生態(tài)環(huán)境，打破固有的深山——淺山——平原相互關(guān)聯(lián)的生態(tài)系統(tǒng)，進而引起城市生態(tài)環(huán)境的惡化，甚至引發(fā)一些地質(zhì)災(zāi)害。

另外，淺山區(qū)由于方便到達，自古以來就是山地中承受開發(fā)建設(shè)壓力最大的區(qū)域，歷史上的人類活動在此留下了豐富的文化遺產(chǎn)。風(fēng)景優(yōu)美、臨近城市的淺山區(qū)往往擁有多樣的人文風(fēng)景資源，如山村聚落、寺廟、園林、書院、摩崖與石刻，等等。人文風(fēng)景薈萃的淺山地帶都是城市重要的風(fēng)景地和觀光休閑地，如果大規(guī)模的城市建設(shè)侵入這里，處理不當(dāng)，必然會帶來風(fēng)景資源的破壞。

中國歷史上有大量山水畫描繪著中國人在淺山地帶的建造實踐，畫面上的山、水、聚落、田園都完美地融合在一起，形成獨特而恬靜的山水風(fēng)景。當(dāng)然，古代的建造技術(shù)較為簡單，山村聚落規(guī)模不大，人們對自然的干預(yù)能力也有限，建造行為總是順應(yīng)自然環(huán)境而為。那么今天，以現(xiàn)代工程技術(shù)為支撐，在淺山地帶建造規(guī)模龐大的城市新區(qū)，我們又如何能夠像古人一樣，實現(xiàn)人工建造與自然山水之間的和諧，建設(shè)具有詩意的家園？

本期的專題為“淺山·都市化中的保護”，收錄的論文分別從不同的角度探究了城市發(fā)展與淺山生態(tài)環(huán)境之間的復(fù)雜動態(tài)關(guān)系，包括政治、經(jīng)濟和文化過程對于淺山景觀變化的影響，淺山景觀變遷的模式和機制，世界主要都市區(qū)的山地開發(fā)管控模式等，希冀能充實和豐富對淺山區(qū)的生態(tài)保護及規(guī)劃建設(shè)的研究。

主編：王向榮教授

2018年12月10日

PREFACE

Urbanization of Low Mountain Area

“Low mountain area” as neither geographical unit nor geomorphological type in strict sense, refers basically to the transitional area from high mountains to plains so inclusive of the terrains of low elevation mountains, hills, terraced tablelands and eroded gullies etc.

With rapid urbanization and population concentration of the developed countries of Europe, the United States and the emerging market countries after the Second World War, there have been increasing shortage of suitable flat land resources for construction.Consequently, more and more low mountain areas were converted into urban construction lands as residential or recreation spaces for citizens.

Low mountain areas are attracting growing attention in course of the rapid urbanization of China. I recently noticed a real estate ad declaring that the low mountain areas of the world all have magnificent residential conditions so real estate prices are often of the highest, and I would approve it. As a mountainous country, China has many cities located at piedmont plains or mountainous basins.With improved traffic condition, one need not travel far from from the city to reach the low mountain areas with beautiful scenery of farmlands and views of mountain and also urban landscape. Driven by various interests, urban development will inevitably extend into low mountain areas. In fact, in the rapid urbanization process around the world, some large-scale constructions have already spread to the low mountain areas around the city.

The urbanization rate of China grew by about 1% annually over the past 30 years and would be predicted to continue growing at a similar rate in the near future. That is to say, with one percentage point of urbanization, a land area about 2,000 square kilometers of non-construction land in China shall be converted into construction land. Such non-construction land include low mountain areas.

Nevertheless, I am deeply concerned about the development construction of the low mountain areas. Firstly, the low mountain areas as intersects of mountain ecosystems and plains are important ecological buffer zones between mountains and plains. They are also the most important water conservation area and groundwater recharge area of the piedmont plains. To these ends, appropriate management of the ecological condition of the low mountain areas is crucial for maintaining the health of the ecosystem of the entire city. With large-scale urban construction spread to low mountain areas without in-depth feasibility study, rational planning and proper construction, the ecological condition of the much sensitive areas would be threatened by the broken inherent ecological linkage among sequence of high-elevation mountain——low-elevation mountain——plains, resulting in deterioration of urban environment even geological disasters.

In addition, due to the easy access of low mountain areas, it have been the areas under the greatest development construction pressure since ancient times, therefore containing abundant historical cultural heritages of humans. The low mountain areas with beautiful scenery, easier traffic to neighboring cities often have abundant cultural and scenic resources, such as rural settlements,temples, gardens, academies, cliff or stone carvings, etc., which are popular for sightseeing, leisure, recreation of the city. Large-scale urban construction invasion into low mountain areas will inevitably jeopardize such cultural or scenic resources.

Chinese history has also witnessed numerous landscape paintings depicting the local people’s construction practices in low mountain areas. In these paintings, the mountains and hills,water network, settlements and farmlands integrate to form unique peaceful landscape. Due to the relatively simple construction technology, the scale of settlement on mountainous is restricted thus the intervention to the nature is limited, so that we can find that the ancient construction behavior are always conformed to its natural environment. Then, with the support of modern facilities and engineering technology, how can we achieve the harmony between artificial construction and natural landscape to build poetic homelands in a similar way of our ancestors when facing the largescale development of low mountain areas?

The theme of this issue is “Hillside: Preservation in Urbanization”. The adopted essays explored the complex dynamic relationship between urban development and ecological condition of low mountain areas from different perspectives, covering the impact of political, economic and cultural processes on landscape change of low mountain areas, the pattern and mechanism of landscape change of low mountain areas, the mountainous development governance model of major metropolitans of the world etc. which I think will enrich the research context on the ecological conservation, planning and construction in the low mountain areas.