Data on the effects of silvicultural thinning and prescribed fire on soil chemistry and foliar physiology of three coniferous species at the Teakettle Experimental Forest, California, USA

These data contain biochemical parameters as measured in foliage from three tree species and related soil chemistry as part of a full factorial experimental design crossing over- and understory silvicultural thinning and prescribed burning at the Teakettle Experimental Forest in the Sierra National Forest, California. Thinning treatments were applied in the fall of 2000 to the plots that were to be thinned and burned, and in the early spring of 2001 to the plots that were thinned only. The prescribed fire treatment was applied in the fall of 2001, after downed fuels had a year to dry. Treatments include: 1) Unburned + Not thinned; 2) Unburned + CASPO (Understory thinning); 3) Unburned + Shelterwood (Overstory thinning); 4) Burned + Not thinned; 5) Burned + CASPO (Understory thinning); and 6) Burned + Shelterwood (Overstory thinning). In early July of 2008 and July 2009, foliage was collected from 5 random Jeffrey pine, sugar pine and white fir trees in each of 3 replicate plots of these 6 treatments (in total, 270 foliar samples from 18 plots); soils were also collected in 2008 (9 cores [split into top/subsoil]) from the same 3 replicate plots and 6 treatments (in total 162 top- and subsoil samples from 18 plots). Foliar data includes free polyamines, free amino acids, soluble ions, total nitrogen (N), total carbon (C), chlorophyll, and soluble protein analyzed by HPLC, ICP-OES, CHNS Combustion Elemental Analyzer, and spectrophotometer. Soil data includes total N and C, extractable ammonium (NH4) and nitrate (NO3), Inorganic Ortho-Phosphate, and exchangeable ions by ICP-OES, ICP-AES, flash combustion quantified by thermal conductivity detection (TCD), and Flow Injection Analyzer (FIA).
The goal of this study was to evaluate the use of metabolic changes in foliage, relative to soil chemistry, as indicators for predicting the effects of thinning and burning treatments on species-specific growth and long-term productivity of Pinus jeffreyi, Pinus lambertiana, and Abies concolor. The overall goal of the experiment was to examine the implications of creating a shift in species composition to favor fire-resistant pines over fir.