Search results for "basal area"
showing 10 items of 18 documents
Patterns of drought tolerance in major European temperate forest trees: climatic drivers and levels of variability
2013
The future performance of native tree species under climate change conditions is frequently discussed, since increasingly severe and more frequent drought events are expected to become a major risk for forest ecosystems. To improve our understanding of the drought tolerance of the three common European temperate forest tree species Norway spruce, silver fir and common beech, we tested the influence of climate and tree-specific traits on the inter and intrasite variability in drought responses of these species. Basal area increment data from a large tree-ring network in Southern Germany and Alpine Austria along a climatic cline from warm-dry to cool-wet conditions were used to calculate indi…
Environmental drivers interactively affect individual tree growth across temperate European forests
2019
Forecasting the growth of tree species to future environmental changes requires a better understanding of its determinants. Tree growth is known to respond to global-change drivers such as climate change or atmospheric deposition, as well as to local land-use drivers such as forest management. Yet, large geographical scale studies examining interactive growth responses to multiple global-change drivers are relatively scarce and rarely consider management effects. Here, we assessed the interactive effects of three global-change drivers (temperature, precipitation and nitrogen deposition) on individual tree growth of three study species (Quercus robur/petraea, Fagus sylvatica and Fraxinus exc…
Ectomycorrhizal fungi in wood-pastures : Communities are determined by trees and soil properties, not by grazing
2019
Traditional rural biotopes such as wood-pastures are species-rich environments that have been created by low-intensity agriculture. Their amount has decreased dramatically during the 20th century in whole Europe due to the intensification of agriculture. Wood-pastures host some fungal species that prefer warm areas and are adapted to semi-open conditions, but still very little is known about fungi in these habitats. We studied how management, historical land-use intensity, present grazing intensity, time since abandonment, and stand conditions affect the species richness and community composition of ectomycorrhizal fungi. We surveyed fruit bodies on three 10 m × 10 m study plots in 36 sites…
Evaluating structural and compositional canopy characteristics to predict the light-demand signature of the forest understorey in mixed, semi-natural…
2020
Questions: Light availability at the forest floor affects many forest ecosystem processes, and is often quantified indirectly through easy-to-measure stand characteristics. We investigated how three such characteristics, basal area, canopy cover and canopy closure, were related to each other in structurally complex mixed forests. We also asked how well they can predict the light-demand signature of the forest understorey (estimated as the mean Ellenberg indicator value for light [“EIVLIGHT”] and the proportion of “forest specialists” [“%FS”] within the plots). Furthermore, we asked whether accounting for the shade-casting ability of individual canopy species could improve predictions of EIV…
An assessment of the floristic composition, structure and possible origin of a liana forest in the Guayana Shield
2015
Liana is a life form that possess high importance in many neotropical forests. Density of climbers apparently increases with the intervention rate (eg. logging). The aim of this work is to characterize the structure, floristic composition and soils of a sector classified as Liana Forest (LF). We identified a LF sector in a not-logged area; three 1 ha square plots were measured (individuals ≥ 10 cm dbh, “diameter at breast height”). In each plot we evaluate four 100 m2 square understory sub-plots (all spermatophyta individuals < 10 cm dbh). LF has a low canopy (< 15 m) and is dominated by Alexa imperatricis and Pentaclethra macroloba. Basal area (20.4 m2ha-1) and diversity (H´= 2.6) ar…
Windthrow in streamside key habitats: Effects of buffer strip width and selective logging
2020
Abstract Streamside forests are preserved from clear-cut logging in production forests and protected with uncut buffer strips in many countries. However, buffer strips often remain narrow due to economic reasons and, therefore, provide weak protection against adverse edge effects of clear-cuts and are vulnerable to windthrow. Selective logging of buffer strips is sometimes allowed to reduce their costs, but the decreased tree density may expose the buffer to higher occurrence of windthrow. We used a replicated two-factor experiment to assess the effects of buffer width (15 m or 30 m) and selective logging (0% or 30% of the basal area removed) on the risk of windthrow in boreal streamside fo…
Living and Dead Aboveground Biomass in Mediterranean Forests: Evidence of Old-Growth Traits in a Quercus pubescens Willd. s.l. Stand
2017
For a long time, human impact has deeply simplified most of the forest ecosystems of the Mediterranean Basin. Here, forests have seldom had the chance to naturally develop a complex and multilayered structure, to host large and old trees and rich biological communities, approaching old-growth conditions. Also for this reason, limited information is currently available about Mediterranean old-growth forests, particularly with regard to deadwood. The main aim of this work is to help fill this critical knowledge gap. In Sicily (Italy), we identified a Quercus pubescens forest that seemed to show some typical old-growth features. Total living volume (360 m3 ha−1) and basal area (34 m2 ha−1) wer…
Soil properties and tree growth along an altitudinal transect in Ecuadorian tropical montane forest
2008
In tropical montane forests, soil properties change with increasing altitude, and tree-growth decreases. In a tropical montane forest in Ecuador, we determined soil and tree properties along an altitudinal transect between 1960 and 2450 m asl. In different vegetation units, all horizons of three replicate profiles at each of eight sites were sampled and height, basal area, and diameter growth of trees were recorded. We determined pH and total concentrations of Al, C, Ca, K, Mg, Mn, N, Na, P, S, Zn, polyphenols, and lignin in all soil horizons and in the mineral soil additionally the effective cation-exchange capacity (CEC). The soils were Cambisols, Planosols, and Histosols. The concentrati…
Managing conservation values of protected sites: How to maintain deciduous trees in white-backed woodpecker territories
2020
Successional and other temporal habitat changes may also affect conservation areas and reduce their conservation value. Active management to promote vulnerable habitat features may be an effective, but controversial, solution. Old deciduous trees and deciduous dead wood in boreal forest reserves are examples of habitat features that may be lost during succession, yet several threatened species, including the white-backed woodpecker (Dendrocopos leucotos), are dependent on them. Encroaching spruce have been removed from white-backed woodpecker territories to promote the regeneration of deciduous trees and to preserve habitat quality, although the efficiency of this treatment is unclear. In t…
Unmanned aerial system imagery and photogrammetric canopy height data in area-based estimation of forest variables
2015
In this paper we examine the feasibility of data from unmanned aerial vehicle (UAV)-borne aerial imagery in stand-level forest inventory. As airborne sensor platforms, UAVs offer advantages cost and flexibility over traditional manned aircraft in forest remote sensing applications in small areas, but they lack range and endurance in larger areas. On the other hand, advances in the processing of digital stereo photography make it possible to produce three-dimensional (3D) forest canopy data on the basis of images acquired using simple lightweight digital camera sensors. In this study, an aerial image orthomosaic and 3D photogrammetric canopy height data were derived from the images acquired …