Forest follies

In an article on Chinadialogue, Xinzhou Song of GreenBeijing.net describes some of the dangers of monocropping:

In the late 1950s, problems arose with the [man-made] Feibo forest reserve in Sichuan, which consisted of Burma Pines. The forest floor was covered with a thick layer of pine needles, which produced no compost and supported no organisms in the soil. Animals and other plants found it hard to survive in such an environment, leaving the forest floor dry and prone to regular forest fires. The soil was also eroded by rain.

Another forest, this time in Heilongjiang and consisting of larches, fell victim to an infestation of pine caterpillars in 2002. A railway operated by the Qiqihar Railway Bureau ran through the forest, and on June 1, several kilometres of the track were covered by a layer of caterpillars two to three inches thick. Passing trains mashed the larvae into a pulp that covered the tracks and stopped the trains...

...Of the more than 400,000 Chinese pines planted in Qingjian County, northern Shaanxi, only about 100 trees remain. The locals call them the “bandits of the hills”. In 2000, the city of Wuhai in Inner Mongolia decided to plant cypresses on 270 square metres of sand dunes. The result? The cypress trees died, and the sand dunes, which had been confined to one area, started to spread.