Some Estonian sawmills may need to close by year end, at least temporarily, as a fall in demand has hit timber producers at a time of soaring energy prices. Sawmills are also facing competition from energy firms making the switch to burning wood and wood-derived products instead of natural gas, while even the hot summer has had its effect.     A fall in demand from the Estonian construction sector in particular has seen the market contract by around 50 percent since early on this year,, and sawmills are also being undercut by energy ...