• Sebastian Thornton posted an update 3 days, 14 hours ago

    ?6). Light availability and leaf area index are measured throughout the entire 90?��?90?m plot on a 15-m grid (25 points per plot) every April and September, when deciduous trees are leafless and leafed-out, respectively. Hemispherical canopy photographs are taken with a Nikon 8-mm ��fisheye�� lens and a Nikon F-3 film camera (prior to 2008) or (since 2008) D-3 digital camera in full-frame (fx) mode (Nikon Inc., Melville, NY, USA). The camera is placed on a self-leveling mount atop a tripod and positioned 1�C2?m above-ground. Hemispherical photographs are analysed for canopy openness and diffuse radiation (��direct site factor�� and ��indirect site factor��, respectively; Rich 1989; Rich et?al. 1993) and leaf area index using HemiView software version 2��1 (Delta-T Devices, Cambridge, UK). As the ecological functioning of a forest stand is often related to the spatial organization of the canopy, we have also used portable canopy laser detection and ranging (LiDAR; Parker, Harding, & Berger 2004) to measure volumetric canopy structure the season after the girdling and logging treatments were completed. LiDAR measures will be repeated at 5- and 15-year intervals to develop an understanding of early structural dynamics and micrometeorological consequences associated with the canopy removal treatments. Forecast changes in nitrogen availability and changes in rates of nutrient fluxes are assessed with resin bags and soil incubations (Roberston et?al. 1999). Changes in carbon efflux (soil respiration) are measured manually every 2?weeks during the growing season between 09:00 and 15:00?hours in permanently embedded 30-cm diameter plastic (PVC) collars using a portable infrared gas analyser (Savage & Davidson 2003). Collars were installed in 2003 and are embedded 10?cm into the soil. Soil moisture within the collars is measured with permanently installed time-domain reflectometry (TDR) probes, at the same time that soil respiration is measured. Net primary productivity (both as litterfall into five randomly located litter baskets and as diameter growth, in-growth and mortality of all trees) and decomposition and turnover of coarse woody debris are assessed throughout the entire 90?��?90-m plot using the line-intercept method of Harmon & Sexton (1996). Re-organization of biotic assemblages is measured as annual changes in species composition and abundance of understorey vegetation and key arthropod groups (ants, carabid beetles and spiders). Understorey vegetation is sampled in five 1-m2 quadrats spaced evenly along each of two transects running north-south or east-west through the core of each plot (Fig.?5). We estimate percent cover of herbs, shrubs and tree seedlings (individuals <1��3?m tall) to the nearest 1% and count the number of seedlings of each tree species. Arthropods are sampled using grids of 25 pitfall traps in the core area of each plot (full methods in Ellison et?al. 2005b).

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