Thursday, August 9, 2007 - 3:20 PM

COS 133-7: Summarizing the Pacific Northwest oceanic conifer forests: A brief phytosociological survey for conservation purposes

Daniel Sánchez-Mata and Salvador Rivas-Martínez. Universidad Complutense

In over more than 15 years of geobotanical research throughout Pacific landscapes of USA (Alaska, Washington, Oregon, California, Nevada, Idaho, Montana Wyoming) and Canada (Yukon, British Columbia) more than 3,000 phytosociological relevés were personally collected following the last approaches on Braun-Blanquet vegetational methods. Our vegetation database (now being studied with multivariate analysis procedures) concerns mainly to forest vegetation where broadly distributed and well-adapted conifers are the dominant tree species.
 
The proposed highest phytosociological units for the Pacific Northwest climactical oceanic conifer forests are:
 
Tsugetea mertensiano-heterophyllae: Boreal and Temperate Pacific Northwest oceanic conifer forests (Tsugetalia mertensiano-heterophyllae), and seral deciduous associated forests as secondary vegetation (Alno rubrae-Populetalia trichocarpae)
Tsugetalia mertensiano-heterophyllae (climactical oceanic conifer forests)
Tsugion heterophyllae: North Western Pacific territories. Mesoboreal, meso-supratemperate, and meso-supramediterranean forest types. Common tree species: Tsuga heterophylla, Abies grandis, Abies amabilis, Picea engelmannii s.l., Picea sitchensis, Sequoia sempervirens, Pseudotsuga menziesii s.l., Thuja plicata, and Tsuga heterophylla
Tsugion mertensianae: North Western Pacific territories. Supraboreal and orotemperate forest types. Common tree species: Abies lasiocarpa, Abies procera, Larix lyallii, Picea engelmannii s.l., Picea sitchensis, Pinus albicaulis, and Tsuga mertensiana
Pinion contortae: Boreal Oceanic Eastern Alaskan, Oregonian-Vancouverian, and Canadian Coastal Mountains territories reaching some Northern Californian coast areas. Thermo-mesoboreal, supratemperate, and mesomediterranean forest types. Common tree species: Pinus contorta s.str., Pinus muricata
 
The phytosociological units for all this forest vegetation have their corresponding units within the various standard American vegetation classification systems. Their relations with US National Vegetation Classification Standards will be discussed.