Effects of prescribed burning on leaves and flowering of Quercus garryana |
| |
Authors: | David H Peter James K Agee Douglas G Sprugel |
| |
Institution: | (1) Pacific Northwest Research Station, 3625 93rd Avenue SW, Olympia, WA 98512-9191, USA;(2) School of Forest Resources, University of Washington, Box 352100, Seattle, WA 98195, USA |
| |
Abstract: | Many woodland understories are managed with prescribed fire. While prescribed burns intended to manipulate understory vegetation
and fuels usually do not cause excessive tree mortality, sublethal canopy damage may occur and can affect tree vigor and reproductive
output. We monitored Quercus garryana trees in western Washington, USA with multiple canopy thermocouples during three prescribed burns. Peak temperatures recorded
in tree canopies ranged from 36 to 649°C. We assessed leaf damage immediately after burning, and flower, leaf and acorn production
in the following year in the vicinity of each thermocouple. Leaf scorch first occurred with peak thermocouple temperatures
around 45°C, was variable up to 75°C, but above 75°C all leaves were killed. Buds, including their reproductive and leaf organs
were more resistant to heat damage than leaves, but leaf scorch had predictive value in forecasting bud organ damage. Staminate
and pistillate inflorescences and acorn production per bud decreased and bud mortality increased with maximum thermocouple
temperature. In two burns where the highest peak temperatures reached 137°C, there was no difference in leaf production between
burned and control plots in the spring following burning. However, no staminate or pistillate inflorescences were produced
when thermocouple peak temperatures went above 55 or 68°C, respectively. While heat damage to bud organs was detected, production
of reproductive organs was also curtailed at temperatures lower than could reasonably be attributed to heat damage. Thus,
it is probable that some other fire-related factor, possibly smoke, was also involved. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|