Rates of litter decomposition, nutrient release, and total forest floor turnover were measured on two replicates of three ecosystem types in the Coastal Western Hemlock Zone of British Columbia, in an attempt to establish whether or not ecosystem types could be differentiated on the basis of functional parameters. Litter bags of two mesh sizes and leaf tethering were used to compare weight losses and nutrient dynamics of specific litter components. The dry weight losses of conifer needles confined in 1 mm mesh bags ranged from 30 to 40 % after one year. There was no significant difference between sites, Weight loss of salal leaves on xeric sites ranged from 20 % after one year for samples confined in 1 mm mesh bags to 45 % for tethered leaf samples. Big-leaf maple weight loss ranged from 15% for samples confined in 1 mm mesh bags to 60 % for tethered samples. Twig samples lost 7 to 21 % of their weight on all sites after six months, with slightly higher values occurring on the hygric sites, Cellulose strips in 4 mm mesh bags lost an average of 23 % of their weight on the-xeric, 21 % on the mesic, and 40 % on the hygric sites. Nutrient mass and concentration changes over one year varied somewhat between different types of foliage litter. The total mass of K, Mg, and Ca decreased in all litter types on all sites, N and P mass changes were more variable, The relative mobility of nutrients released from decomposing conifer litter was Ca> Mg?P>K>N, and from broad-leaf litter was Ca>Mg>K>P>N. The low mobility of K was concluded to be due to leaching of this element from the litter prior to its collection for the study. Numbers of fauna in the forest floor were compared on one replicate of each of the ecosystem types at six week intervals throughout the year. Micro-fauna were more abundant on the xeric and mesic sites, while macro- and meso-fauna were more numerous on the hygric sites. Numbers were lowest on all sites when forest floor moisture was lowest in August. At other times of the year population fluctuations were different for different fauna groups. Forest floor biomass was also measured on one replicate of each ecosystem type. It averaged 45,05 tonnes • ha⁻¹ on the xeric sites, 45.68 tonnes • ha⁻¹ on the mesic sites, and 25,20 tonnes • ha⁻¹ on the hygric site. Annual forest floor turnover rates were calculated to be .015 for the xeric, ,017 for the-mesic, and ,040 for the hygric sates, Differences in turnover rates between sites were attributed more to differences in the quantities- of wood and herbaceous foliage on the three sites than to differences in the decomposition rates of individual substrates. / Forestry, Faculty of / Unknown

Cheng Suet Ha. / Bibliography: leaves 179-195. / Thesis (M.Phil.)--Chinese University of Hong Kong.

published_or_final_version / Botany / Master / Master of Philosophy

published_or_final_version / Zoology / Master / Master of Philosophy

Sugar maple foliage litters from fertilized and unfertilized plots on a base-poor site and from a naturally base-rich site were incubated in litterbags of 1 and 3 mm mesh on fertilized and unfertilized plots at the base-poor site. Mass loss of unfertilized litter was slower in fertilized than unfertilized plots, suggesting a negative effect of fertilization on decomposers. Mass loss of fertilized litter was faster than unfertilized litter in the same plots, indicating that changes in litter quality due to fertilization enhanced microbial decomposition. Mass loss was higher in large mesh than in small mesh size bags, suggesting that larger soil fauna played a significant role in litter decomposition. / Potassium appeared to be rapidly leached, whereas Ca and Mg were released at rates more closely related to litter mass loss. Nitrogen was mineralized from N-rich Arboretum litter only; all other litters immobilized N. Release of Ca and Mg was reduced significantly on fertilized plots. Large soil fauna enhanced Ca release, while they delayed N-mineralization in Arboretum litter.

No description available.

Includes bibliographical references

The microbial Population of stream leaf litter was examined during the fall and winter of 1976 in Bell Creek, Delaware County, Indiana. Nylon-mesh bags containing leaves were placed in the creek and allowed to become colonized by bacteria and fungi. Of special interest was the enumeration and identification of cellulolytic anaerobic bacteria. This study revealed the presence of these bacteria in all sample cases. These bacteria were generally identified as belonging to the genus Clostridium. Two species of cellulolytic pseudomonads were also isolated. Non-cellulolytic bacteria belonging to the genera Flavobacterium and Beijerinckia were isolated. These aerobic organisms may function indirectly in cellulose degradation by removing toxic byproducts or growth limiting factors.

published_or_final_version / Geography and Geology / Master / Master of Philosophy

No description available.