maackii fine roots were severed by trenching than in untrenched areas (Fig.
maackii, established a trenched and an untrenched subplot within each plot, and measured the water content of the soil daily after periods of rain.
Although trenching was not a significant factor, there was a significant interaction between trenching and days: the soil in trenched subplots dried more quickly than that in untrenched subplots (Table 1, Fig.
maackii were drier than those without, and trenched subplots were wetter than untrenched subplots.
The test was designed to demonstrate the system's performance in both trenched and untrenched
mode and with different surface coupling solutions.
Hart and Sollins (1998), in contrast, did not find a close correspondence between laboratory and in situ determinations (using a resin-core method; Hart and Perry 1999) of soil N mineralisation in untrenched
and trenched plots in an old-growth conifer forest.
Nevertheless, Putz and Canham (1992) recommended compensating for the effects of decomposing roots (whether positive or negative) by adding severed roots to untrenched
Some investigators have compensated for root decomposition by adding severed roots to untrenched plots (Putz and Canham 1992), while others argue that nutrients released from severed roots are objects of past competition (Aarssen and Epp 1990), and that trenched plots mimic natural belowground gaps (Coomes 1995).
One trenched plot in the understory was abandoned because of a treefall, and three trenched plots in gaps were taken out of all analyses because incident light measurements were considerably higher than for any untrenched plots ([approximately]9% vs.
Although competition for water seemed improbable, we investigated water relations by monitoring soil moisture potential during the dry season and by measuring the midday stomatal resistance of trenched and untrenched plants during the driest part of the year.
Root competition treatments were untrenched
. No herbivory plants were sprayed with malathion (2.95 milliliters per liter) once each week for the duration of the experiment.