Structure and physiology of the world’s tallest trees, Part 1: Hierarchical sampling permits whole-tree analyses

Forty-five trees, selected from amongst the tallest known individuals of the tallest angiosperm (Eucalyptus regnans up to 92.4 m) and the two tallest conifers (Pseudotsuga menziesii up to 96.9 m and Sequoia sempervirens up to 112.9 m) were mapped for every trunk, limb, and branch.  For each species, five of the trees were among the tallest known, an additional five were 80% of maximum height, and another five were 60% of maximum height.  Structural mapping included all necessary information for reconstructing tree crowns in three dimensions.  Trunks and limbs were separated into segments, whose ends were each measured for diameter and XYZ coordinates.  Branch bases also received these measurements, as well as the XYZ coordinates of their distal tips.  Leaf biomass was quantified separately for every structural element on the tree.  Within the population of all branches (1065 Eucalyptus, 950 Pseudotsuga, and 3322 Sequoia), a subset that spanned the entire size and height range was removed for detailed measurements of leaf dry mass as well as axis path-length, bark thickness, and sapwood depth at every 1-cm-diameter interval.  A subset of limbs and trunks were also cored to estimate bark thickness and sapwood depth.  Through regression analysis we were able to quantify leaf biomass, projected leaf area, cambium surface area, bark volume, sapwood volume, and heartwood volume at the whole-tree level.  The complete, structural inventory followed by stratified random sampling permitted accurate calculation of these previously unobtainable quantities for the world's tallest trees, setting the stage for future whole-tree physiological analyses.