Ground Vegetation Biomass, Production, and Efficiency of Energy Utilization in Some Northern Wisconsin Forest Ecosystems

Abstract

The aboveground biomass of the herb stratum, including woody species up to 30 cm tall, was determined by harvesting annually over a 4—yr period (1969—72) in aspen, maple—aspen—birch, birch, northern hardwood, and logging road communities. Average aboveground biomass in the respective community types was 117.5, 63.0, 51.0, 37.6, and 80.6 g/m2. Root biomass was determined by harvesting the belowground part on selected plots in 1971. Cumulative solar energy received at the sample points was measured with a chemical integrating light meter (petroleum ether chlorophyll extracts). Phenological observations indicated that net annual production in the four forest types was essentially equal to their end—of—season standing crop biomass. Average root:top ratios ranged from 2.98 to 4.79 and were higher in the dry communities (birch and northern hardwood) than in the other more mesic forest. Except for the logging road, two to five species accounted for most of the biomass in each community. Significant positive correlations were found between incident solar energy and aboveground biomass. Efficiency ranged from 0.82% to 2.19% based on May—October cumulative energy in the visible spectrum and cover adjusted aboveground biomass.

Aboveground Biomass Estimation of Individual Trees in a Coastal Planted Forest Using Full-Waveform Airborne Laser Scanning Data

“…This is likely due to: (1) the crown shape of the coniferous trees in the study site tends to be conical and relatively isolated, which are likely to be detected by the local maxima algorithm used in this study, whereas trees in other studies may have more rounded crowns (e.g., broadleaved tree species) that are likely to overlap, or suppressed under the dominant canopies that may not be successfully detected; (2) the local maxima algorithm was applied on a CHM created from a relatively high density point clouds (approximate 9.2 pts·m −2 in the study site) extracted from full-waveform data by decomposition algorithms; and (3) the size of the search window was determined by a model fitted by the locally collected field measurements, which may enhance the performances of tree top identification. In this study, as most of the dominant trees were correctly detected by the tree detection algorithm, the ITC approach can be effective because dominant trees are usually the main contributors to AGB in forest stands [73]. However, it should be noted that the errors in tree identification will be transferred into the AGB summaries at plot or stand level, and can result in the estimation of AGB with considerable systematic errors.…”

Relationship between biomass and percentage cover in understorey vegetation of boreal coniferous forests

“…In any season, the biomass of the belowground parts of the vegetation is substantially higher than that of the aboveground parts (Zavitkovski 1976, Kubícek and Simonovic 1982, Kubícek et al 1994. The amount of belowground biomass of grasses, herbs and dwarf shrubs in coniferous forests was estimated to be twice as large as the maximum biomass of the aboveground parts during the growing season (Mälkönen 1974, Perina and Kvet 1975, Kubícek and Simonovic 1982, Havas and Kubin 1983, Kubícek et al 1994.…”

“…However, it may play an important role in many ecosystem processes, e.g. in the nutrient and carbon cycle (Yarie 1980, Van Cleve andAlexander 1981), due to rapid turnover at the biomass level and the presence of easily decomposable litter (Tappeiner and Alm 1975, Zavitkovski 1976, Chapin 1983. In upland soils, the annual litter production of understorey vegetation may represent a considerable proportion of the total litter production, varying from 4% to 30% (Hughes 1970).…”

Predicting and managing light in the understory of boreal forests

“…In a relatively stable forest system, the biomass of the understory is inversely correlated with the density of the overstory (Zavitkovski 1976;Cannell and Grace 1993;Brown and Parker 1994;Lieffers and Stadt 1994;Ricard and Messier 1996). A long-term strategy for controlling shrub and herb competition during the regeneration phase is to develop dense overstory canopies at the end of the rotation.…”