A garden on the sea

A visit to the man-made Beiji Island in northeast China brings to mind an ancient saying that states that time has the power to transform seas into farms. But what turned the coastal region into a sea of flowers was not the vicissitudes of time, but the power of human technology.

Although reclamation is not a cutting-edge technology, turning salinized land into a garden is difficult, particularly for Beiji, which was designated as the site for the 13th World Landscape Art Exposition.

A day prior to the expo's opening on Friday, the tiny island is blooming with millions of flowers thanks to the application of new technologies that resist sea water erosion and coastal winds.

In one garden, thousands of tulips imported from Holland are in half or full bloom, forming scarlet, yellow and white belts that wind halfway across the island.

A total of 130,000 trees and 30 million flowers have been planted in the park to complement garden designs created by artists from across the world, the expo's organizers said.

Previously made up of foreshores and disused shrimp farms, the expo park came out of a massive reclamation project that has poured 20 million cubic meters of sand and soil into the sea since 2011.

"The expo required a large piece of land, but we decided not to occupy any farmlands. That's why we chose the barren saline-alkali foreshores," said Yi Xinyang, an official in charge of the construction and design of the expo.

But filling in the sea resulted in one problem: despite copious marine elements and a balmy oceanic climate, trees and flowers can barely survive on the island, as its foundation is full of seawater.

"If you dig 1.7 meters down, you' ll find the island's foundation is filled with seawater, which salinizes the upper layers of soil and causes the plants to wither," said Liu Yulan, a gardening expert who worked to green the island.

To solve the salinization problem, Liu and her colleagues introduced desalting technologies, including paving a layer of gravel and non-woven fabric beneath the soil to stop the upward movement of underground saline water.

Other technologies include "breathing" concrete ground, the loose structure of which allows rainwater to be absorbed quickly, thus helping to wash out the salt and desalinate the underground water.

The measures have ensured the survival of 95 percent of the 130,000 trees that became the first "settlers" on the island one year ago, Liu said.

Delicate flowers were the last to settle down. Horticulturists planted them mostly in low-lying inland areas, with surrounding hills hemmed by tougher trees to deflect strong gales.

Human labor still plays a big part in maintaining the fragile ecosystem. On windy days and during typhoon season, staff need to patrol the island to reinforce trees with support pillars while keeping an eye on the potential backflow of seawater.

Some of the island's rarer trees are even given "IV drips" that provide them with nutrients to sustain their growth, Liu said.

"When tourists appreciate the island's natural beauty, we hope they will also keep in mind that the scenery would not be there without the immense effort and devotion of many technicians and horticulturists," Liu said.