Aquatic insect secondary production, emergence, and export of adults to the adjacent terrestrial ecosystem were assessed in Sycamore Creek, Arizona, by means of benthic sampling, emergence traps, and catch-nets that passively sampled adults falling into the stream. Annual secondary production was 120.9 ? 18.0 g-m-2 yr-t and emergence was 23.1 g.m-2 yr-t (in dry mass units). The ratio of annual ...

dieback of trees is a serious problem in many different regions of the world and city authorities are concern about conserving and maintaining the green spaces in the big cites. this study was conducted to evaluate the early dieback and yellowing of sycamore trees (platanus sp.) by using a completely randomized block design (split split plot) in 15 replications (sites) in 2009. the main plot wa...

Secondary production (measured as dry mass) of collector macroinvertebrates of Sycamore Creek, Arizona, estimated by the size-frequency method, is 135 g m-2. yr-'. This high rate of production is attributed to a long growing season, continuous reproduction, rapid life cycles of major taxa, and small size at maturity. Assimilation efficiency for selected collector taxa is estimated to be 7-14% a...

A continuous-speed felling and bunching prototype machine was evaluated in harvesting a three-year-old, short-rotation sycamore plantation. A small tractor, grapple skidder, and large chipper were evaluated along with the prototype machine as complete harvesting systems. Prediction equations, production rates, and costs were developed for each component of the systems. Production of the feller ...