Martha Creek - Thousand year chronosequence

This dataset is the age 99 Martha Creek Site of the 1KCS study. We examined stand-level and within-tree structural diversity along a 1000-year chronosequence of temperate coniferous forests. Eight stands were established in the southern Washington Cascades Range in 2000, spanning ages of 50 to 950 years old. Within each stand, randomly located transects were laid out in proportion to the dominant tree height for the stand. Tree heights and diameters ranged up to 90 m and 309 cm. A total of 5,737 trees among the 32 transects were mapped and measured for height, diameter, crown height, and four crown radii. The structure of the canopy develops from a simple, fairly even monolayer in the youngest stands to a very complex, highly diffuse canopy with extreme variability in both horizontal and vertical dimensions. The stands with the highest component of structural complexity were aged between 500 and 650 years and retained from 17 to 76 Pseudotsuga/ha. Mean diameter of just the Pseudotsuga trees was less than 55 cm for stands less than 200 years, rising to means over 180 cm for the most complex old-growth stands. One measure of stand structural diversity used was the standard deviation of dbh, which ranged from values less than 25 for stands less than 200 years to values in excess of 50 for the most complex old-growth sites. A similar, but slightly weaker relationship was also present when using the standard deviation of height. Large snags and logs important for wildlife were only abundant in the old-growth, with abundance highest in the most complex stands.