In 1901 British planters introduced rubber trees into the Malay Peninsula, where the soils and climatic conditions were highly suited to rubber cultivation. In Thailand early government restrictions on foreign investment led to development of the industry by local smallholders, usually subsistence rice farmers who were able to start rubber tree stands on the relatively abundant free land in the area. Land under rubber cultivation expanded rapidly in the 1930s, consisting mainly of smallholdings controlled by Chinese, Thai, and Thai Malays rather than large, European-owned plantations, as in other Asian countries. Thailand had about 1.6 million hectares in rubber in the mid-1970s, of which about 10 percent were located in an area along the Gulf of Thailand southeast of Bangkok. Of the 500,000 holdings in the early 1980s, about 150,000 were under 2.5 hectares in size, and another 300,000 were under 10 hectares. The remaining larger holdings were operated more as expanded smallholdings than as plantations. Production was increasing in the early 1980s and had reached about 830,000 tons in 1987. An extensive replanting program, in which old tree stock was replaced with new high-yield varieties, had reportedly been carried out in about half the planted area by the mid-1980s, significantly increasing the potential for expanded production.