NCCN Monitoring Forest Vegetation

Cole, Carla; Fallon, Beth; Boetsch, John; Copass, Catharine

Monitor trend in the processes of tree recruitment, growth, and mortality, and forest structure and composition. The data set consists principally of observations concerning the suitability of potential monitoring locations, and repeated observations of individual trees at locations selected for monitoring. Purpose: Late-successional, coniferous forest is critical for ecosystem function and biological conservation in the Pacific Northwest. As part of Vital Signs Monitoring for the NCCN, the following items are tracked: trends in tree recruitment, growth, and mortality in forests representing the range of environments in the NCCN parks. Monitoring changes in unmanipulated forests in national parks helps managers of harvested lands to practice sustainable management in the face of increasing environmental threats. Monitoring can also provide early warning of the types and severity of future changes in the parks themselves, so that management options can be developed and evaluated in time to be effective. Objectives are to monitor trend in the processes of tree recruitment, growth, and mortality, and forest structure and composition. The data set consists principally of observations concerning the suitability of potential monitoring locations, and repeated observations of individual trees at locations selected for monitoring. As of fall 2010, we had evaluated over 1700 potential monitoring locations in the office, recording the assessment of those points with respect to safety of access routes and proximity to trails and roads and other factors, as evaluated using GIS. For the nearly 600 points evaluated in the field, the data set contains information on plant species composition, forest age, safety of access, and physical attributes of the points. At the locations selected for monitoring, we record species, status (living or dead), diameter, and crown attributes of trees. For living trees, status is recorded annually. For trees which are observed to have died since the previous assessment, the data set contains information on signs and symptoms which may allow us to assign a cause of death. REGARDING what species and communities examined: Late-successional, coniferous forest: western hemlock, Sitka spruce, Subalpine fir. The general approach is to focus on coniferous forest zones that represent the range of climatic regimes and elevation in the NCCN. We sample relatively warm and wet conditions in the Picea sitchensis zone, cold and dry conditions in the Abies lasiocarpa zone, plus the intermediate Tsuga heterophylla zone, which is represented in all three large parks (Mount Rainier, North Cascades, and Olympic). Limited resources and the need for sample replication require that we further focus on particular vegetation associations within forest zones. REGARDING items excluded from data collection: GRTS-based sampling points were excluded from consideration due to site steepness (greater than or equal to 35 degrees slope), unsafe access routes (e.g., major river crossings), proximity to trails and roads ( 1500 m), and other factors including site disturbance, presence of a non-target vegetative type, or presence of unsafe local conditions. Site evaluations were conducted using a combination of GIS elevation data, remotely-sensed imagery, and on-site reconnaissance. For live trees, stems less than 2.5 cm dbh are excluded from measurement in the entire plot. Stems less than 12.7 cm dbh are measured within nine, 10 x 10 m subplots, but are otherwise excluded from measurement. Stems less than 76.2 cm are measured within the 50 x 50 m area comprising the center of the plot, but are otherwise excluded from measurement. For snags (standing dead trees), stems less than 12.7 cm are excluded from measurement in the entire plot. Snags less than 76.2 cm are measured within the 50 x 50 m area comprising the center of the plot, but are otherwise excluded from measurement. REGARDING advice/ca

NCCN Monitoring Forest Vegetation

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