Opperman Jeff J
Department of Environmental Science, Policy, and Management, University of California, Berkeley, Berkeley, California 94720, USA.
Environ Manage. 2005 Mar;35(3):266-77. doi: 10.1007/s00267-004-0068-z.
Although large woody debris (LWD) has been studied extensively in conifer-dominated watersheds, relatively little is known about LWD in hardwood-dominated watersheds. Field surveys of 32 hardwood-dominated stream reaches in northern coastal California revealed that levels of LWD varied with land ownership and that living trees strongly influenced debris jam formation. Almost half of the channel-spanning debris jams, which stored the most wood and were most likely to form a pool, were formed behind a key piece that was still living. These living key pieces might provide greater longevity and stability than would otherwise be expected from hardwood LWD. Compared to streams on private land, streams on public land had significantly greater LWD loading and debris-jam frequency. Land management practices that remove wood from streams might be contributing to the degradation of salmonid habitat in California's hardwood-dominated watersheds.
尽管大型木质残体（LWD）在针叶树为主的流域已得到广泛研究，但对于阔叶树为主的流域中的大型木质残体却知之甚少。对加利福尼亚州北部沿海32条以阔叶树为主的溪流河段进行的实地调查显示，大型木质残体的水平随土地所有权而变化，且活树对碎屑堰塞体的形成有强烈影响。几乎一半横跨河道的碎屑堰塞体储存了最多的木材且最有可能形成水潭，这些堰塞体是在一棵仍存活的关键树木后面形成的。这些活的关键树木可能比阔叶树大型木质残体原本预期的具有更长的寿命和更高的稳定性。与私人土地上的溪流相比，公共土地上的溪流具有显著更高的大型木质残体负载量和碎屑堰塞体频率。从溪流中移除木材的土地管理做法可能正在导致加利福尼亚州阔叶树为主的流域中鲑鱼栖息地的退化。
