Kenya, the world's biggest exporter of black tea, has lost a significant part of its tea production for this month due to severe frost in key growing areas, which could cut its foreign exchange earnings, a major industry group said on Thursday.

In this week alone, about 20 million kg of green leaf was damaged by frost, which occurs when temperatures plunge at night after hot days, said Alfred Njagi, general manager of operations at the Kenya Tea Development Agency (KTDA).

The agency earlier had projected green tea production for January at 85 million kg.

KTDA groups most of the country's small-scale tea farmers, jointly produce an estimated 60 percent of Kenya's tea exports.

"We are looking at about 20 million kg of green leaf we have lost, whose value is in the region of Sh1 billion ($11.4 million)," Njagi said, adding that this was the worst ever case of frost to hit the country.

"There is frost bite across all the tea growing areas ... we expect that severe weather may continue having an effect."

The rest of the country's tea exports are produced by privately owned plantations. Officials at several plantations could not be immediately reached for comment.

The Tea Board of Kenya could also not immediately give a figure for the loss in output countrywide.

Tea is the highest foreign exchange earner in east Africa's leading economy, and exports of the commodity are expected to rake in an estimated record 106 billion shillings in 2011, up from Sh97 billion in 2010. ID:

Njagi said the frost damage is expected to extend into the future, following adverse effects of climate change.

"The conditions that precipitate frost bite have not been eroded, which are very high day temperatures and very low night temperatures. The drop in temperature from day to night is very rapid, so young shoots tend to freeze," Njagi said.

Following the frost, KTDA has downscaled its estimate of January production to 65 million bags of unprocessed tea. The worst hit areas are mostly in the Rift Valley.

It takes about two to three months for tea bushes to recover from such a frost, Njagi said.

Total national exports of the commodity stood at 247.3 million kg last year down from 259 million in 2010. ($1 = 87.9000 Kenyan shillings).

(Reuters)