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from surface and ground water sources combined (minero- <br />trophic /fens). All Colorado peatlands are minerotrophic; with <br />most receiving the majority of their water from ground sources. <br />Normally, the ground water table remains at or very near the <br />surface for most of the growing season, but this may fluctuate in <br />response to periods of precipitation and evaporation (depending <br />on the degree of surface water influence). Seasonal variations <br />in the moisture relations of the peatland will occur if surface <br />water is important in the peatland. Springs and ground water <br />flows are also variable, but less so than surface waters which in <br />the short term are more reliant on precipitation. In any event, <br />the water supply must be consistent enough to allow the upper <br />layer of peat to survive the driest part of the year without <br />irreversible desiccation (Richardson 1989). Cooper (personal <br />communication 1989) has suggested that this may not be as <br />important for Rocky Mountain peatlands. <br />Peatlands develop through the accretion of organic residues. <br />The rate of accretion is very slow, and is variable from place to <br />place. For example, in Ireland and Finland accretion rates of <br />1.0 mm per year are common, a Massachusetts bog was estimated to <br />accrete at 0.53 mm per year, and in the pocosins of North <br />Carolina (extensive peatland deposits on the coastal plain), <br />which are among the fastest accreting, the rate is 1.0 cm per <br />year (Richardson 1989). Pennak (1963), however, noted average <br />accretion rates for several Boulder County peatlands of between <br />0 3 <br />