Basal Area Increment (basal + area_increment)

Distribution by Scientific Domains

Selected Abstracts

Tree Basal Growth Response to Flooding in a Bottomland Hardwood Forest in Central Ohio,

Christopher J. Anderson
Abstract:, Tree basal growth in response to flooding regime was evaluated at a 5.2-ha bottomland forest along the Olentangy River in central Ohio. Tree-ring analysis was used to develop a 14-year basal area increment (BAI) (cm2/year) series for 42 canopy trees (representing 10 species) throughout the bottomland. Mean annual BAI was evaluated relative to the frequency and duration of bankfull (>70 m3/s) and high-flood (>154 m3/s) river discharge for a given water year (October 1-September 30) and growing season (April 1-September 30). A significant polynomial relationship was detected between the number of days of high-flood river discharge over a combined two-year period (Year i + Year i , 1) and mean annual BAI. No significant relationships were detected when only the concurrent-year or previous-year flood regimes were considered or when growing season was considered. A similar relationship was detected when duration of high-flood discharge days and BAI were both evaluated in two-year increments (Year i + Year i , 1). Mean annual BAI was most influenced by boxelder (Acer negundo) which was the dominant species and exhibited strong agreement with the overall BAI series. In each case, the resulting parabolic curve of tree basal growth in response to flooding suggests an optimal number of flooding days, a response to perturbation consistent with the subsidy-stress model. Dendrochronology may be a useful tool for managers looking to restore environmental flows to regulated rivers. [source]

Tree mortality and effects of release from competition in an old-growth Fagus-Abies-Picea stand

Jerzy Szwagrzyk
Abstract. In a montane mixed Fagus-Abies-Picea forest in Babia Gora National Park (southern Poland), the dynamics of an old-growth stand were studied by combining an 8-yr annual census of trees in a 1-ha permanent sample plot with radial increments of Abies and Picea growing in the central part of the plot. The mortality among the canopy trees was relatively high (10% in 8 yr), but the basal area increment of surviving trees slightly exceeded the losses caused by tree death. DBH increment was positively correlated with initial diameter in Abies and Picea, but not in Fagus. For individual trees smaller than the median height, basal area increment was positively related to the basal area of old snags and the basal area of recently deceased trees in their neighbourhood, but negatively related to the basal area of live trees. Dendrochronological analysis of the past growth patterns revealed numerous periods of release and suppression, which were usually not synchronized among the trees within a 0.3 ha plot. The almost normal distribution of canopy tree DBH and the small number of young individuals in the plot indicated that stand dynamics were synchronized over a relatively large area and, hence, were consistent with the developmental phase concept. On the other hand, the lack of synchronization among periods of growth acceleration in individual mature Abies and Picea trees conforms more closely to the gap-dynamics paradigm. [source]

Growth,mortality relationships as indicators of life-history strategies: a comparison of nine tree species in unmanaged European forests

OIKOS, Issue 6 2008
Jan Wunder
Forest succession depends strongly on the life history strategies of individual trees. An important strategic element is the ability to survive unfavourable environmental conditions that result in strongly reduced tree growth. In this study, we investigated whether the relationship between growth and mortality differs among tree species and site conditions. We analysed 10 329 trees of nine tree species (Picea abies, Taxus baccata, Fagus sylvatica, Tilia cordata, Carpinus betulus, Fraxinus excelsior, Quercus robur, Betula spp. and Alnus glutinosa) from unmanaged forests of Europe: the continental Bia,owie,a forest (Poland) and several oceanically influenced Swiss forest reserves. For each species, we calculated a set of flexible logistic regression models with the explanatory variables growth (as measured by relative basal area increment), tree size and site. We selected the species-specific model with the highest goodness-of-fit and calculated its discriminatory power (area under the receiver operating characteristic curve, AUC) and calibration measures. Most models achieved at least a good discriminatory power (AUC>0.7) and the AUC ranged from 0.62 to 0.87; calibration curves did not indicate any overfitting. Almost all growth,mortality relationships differed among species and sites, i.e. there is no universal growth,mortality relationship. Some species such as F. excelsior showed reduced survival probabilities for both unfavourable and very good growth conditions. We conclude that the growth,mortality relationships presented here can contribute to the life-history classification of trees and that they should also help to improve projections of forest succession models. [source]

Tree Diversity, Forest Structure and Productivity along Altitudinal and Topographical Gradients in a Species-Rich Ecuadorian Montane Rain Forest

BIOTROPICA, Issue 2 2010
Jürgen Homeier
ABSTRACT We studied the spatial heterogeneity of tree diversity, and of forest structure and productivity in a highly diverse tropical mountain area in southern Ecuador with the aim of understanding the causes of the large variation in these parameters. Two major environmental gradients, elevation and topography, representing a broad range of climatic and edaphic site conditions, were analyzed. We found the highest species richness of trees in valleys <2100 m. Valleys showed highest values of basal area, leaf area index and tree basal area increment as well. Tree diversity also increased from ridges to valleys, while canopy openness decreased. Significant relationships existed between tree diversity and soil parameters (pH, total contents of Mg, K, Ca, N and P), and between diversity and the spatial variability of pH and Ca and Mg contents suggesting a dependence of tree diversity on both absolute levels and on the small-scale heterogeneity of soil nutrient availability. Tree diversity and basal area increment were positively correlated, partly because both are similarly affected by soil conditions. We conclude that the extraordinarily high tree species richness in the area is primarily caused by three factors: (1) the existence of steep altitudinal and topographic gradients in a rather limited area creating a small-scale mosaic of edaphically different habitats; (2) the intermingling of Amazonian lowland plant species, that reach their upper distribution limits, and of montane forest species; and (3) the geographical position of the study area between the humid eastern Andean slope and the dry interandean forests of South Ecuador. [source]

Effects of Season, Rainfall, and Hydrogeomorphic Setting on Mangrove Tree Growth in Micronesia

BIOTROPICA, Issue 2 2007
Ken W. Krauss
ABSTRACT Seasonal patterns of tree growth are often related to rainfall, temperature, and relative moisture regimes. We asked whether diameter growth of mangrove trees in Micronesia, where seasonal changes are minimal, is continuous throughout a year or conforms to an annual cycle. We installed dendrometer bands on Sonneratia alba and Bruguiera gymnorrhiza trees growing naturally within mangrove swamps on the islands of Kosrae, Federated States of Micronesia (FSM), Pohnpei, FSM, and Butaritari, Republic of Kiribati, in the eastern Caroline Islands of the western Pacific Ocean. Trees were remeasured monthly or quarterly for as long as 6 yr. Annual mean individual tree basal area increments ranged from 7.0 to 79.6 cm2/yr for all S. alba trees and from 4.8 to 27.4 cm2/yr for all B. gymnorrhiza trees from Micronesian high islands. Diameter increment for S. alba on Butaritari Atoll was lower at 7.8 cm2/yr for the one year measured. Growth rates differed significantly by hydrogeomorphic zone. Riverine and interior zones maintained up to seven times the annual diameter growth rate of fringe forests, though not on Pohnpei, where basal area increments for both S. alba and B. gymnorrhiza were approximately 1.5 times greater in the fringe zone than in the interior zone. Time-series modeling indicated that there were no consistent and statistically significant annual diameter growth patterns. Although rainfall has some seasonality in some years on Kosrae and Pohnpei and overall growth of mangroves was sometimes related positively to quarterly rainfall depths, seasonal diameter growth patterns were not distinctive. A reduced chance of moisture-related stress in high-rainfall, wetland environments may serve to buffer growth of Micronesian mangroves from climatic extremes. [source]