Info

-1.35(33)

-0.948'

aWhere the annual exponential loss rate (k) is estimated from a semilogarithmic regression (base e) of monthly weight loss of litterbags.

From Cromack, 1973.

aWhere the annual exponential loss rate (k) is estimated from a semilogarithmic regression (base e) of monthly weight loss of litterbags.

From Cromack, 1973.

usefulness for comparative studies and for nutrient measurements makes them important tools, nevertheless.

Alternatives to litterbags and modifications of the standard approach have been reported. For example, individual leaves tied together by their petioles on a string ("trot-lines") were used by Crossley (unpublished data). Loss of weight (and area) by individual leaves measured through time yields estimates of litter breakdown rates. When biological activity increases in late spring and summer, rapid rates of loss are found. It is not clear whether these rapid losses are due to the separation of large fragments from the leaf, or if the unbagged rates allow for larger fauna to attack the decomposing leaf, or both. The simultaneous use of both techniques yields estimates of breakdown rates that doubtless bracket the true values. Blair and Crossley (1991) used "litter baskets," which confine an entire block of mineral soil, along with the L, F, and H layers, within wire mesh to study litter decomposition and nutrient transport down the soil profile. A further recent modification of the technique is that of "litter sandwiches" (Binkley, 2002), in which fiberglass mesh is placed each year on the annual accumulation of litterfall on a defined area of forest floor. Each subsequent year of decomposition can then be measured over an extended period of time. Binkley (2002) found that 80% of litter organic matter decomposed over 10 years in a loblolly pine forest, yielding k = 0.1655; the data predicted the steady state forest floor mass within 10% of the actual value.

0 0

Post a comment