Learn More
Intra-annual radial growth rates and durations in trees are reported to differ greatly in relation to species, site and environmental conditions. However, very similar dynamics of cambial activity and wood formation are observed in temperate and boreal zones. Here, we compared weekly xylem cell production and variation in stem circumference in the main(More)
Temperature is the most important factor affecting growth at high altitudes. As trees use much of the allocated carbon gained from photosynthesis to produce branches and stems, information on the timing and dynamics of secondary wood growth is crucial to assessing temperature thresholds for xylogenesis. We have carried out histological analyses to determine(More)
The diameter of vascular conduits increases towards the stem base. It has been suggested that this profile is an efficient anatomical feature for reducing the hydraulic resistance when trees grow taller. However, the mechanism that controls the cell diameter along the plant is not fully understood. The timing of cell differentiation along the stem was(More)
Neither anatomical change nor physiological abnormalities have been observed in the cambia of older trees. However, different sensitivity and period of significant responses to climate suggest the existence of some age-related change in the patterns of cambial activity and/or wood cell formation. Here, weekly cambial activity and timing and duration of(More)
The authors compared 16 nondepressed obsessive-compulsive patients (OCS) with 8 normal controls (NC) of similar age for resting-state regional cerebral glucose metabolic rates (rCMRglu) using positron emission tomography with the fluorodeoxyglucose method. OCS were rated for clinical data, and a neuropsychological battery was administered to 14 patients on(More)
Xylogenesis was monitored during 2003 and 2004 in a timberline environment in southern Italy to assess links between temperature, cambial phenology and wood formation on a short-time scale. Wood microcores were collected weekly from May to October from 10 trees of Pinus leucodermis Ant., histological sections were cut with a rotary microtome and anatomical(More)
Variation in tree stem diameter results from reversible shrinking and swelling and irreversible radial growth, all processes that are influenced by tree water status. To assess the causal effects of water and temperature on stem radial variation (DeltaR) and maximum daily shrinkage (MDS), the diurnal cycle was divided into three phases: contraction,(More)
The Canadian forest industry is turning its attention towards the unmanaged areas at higher latitudes, where the forest resource is still poorly understood because of lack of accessibility. Despite a lower productivity in terms of volume, northern stands are expected to produce wood of higher quality, which may make these areas attractive for management and(More)
Because of global warming, high-latitude ecosystems are expected to experience increases in temperature and drought events. Wood formation will have to adjust to these new climatic constraints to maintain tree mechanical stability and long-distance water transport. The aim of this study is to understand the dynamic processes involved in wood formation under(More)
Cambial activity is influenced by many environmental and physiological factors and among them, carbon acts as a source of energy for the growing meristems. This work has focused on the intra-annual stem growth of poplar compared with the carbon available for xylogenesis processes in cambium and outer wood. The major stages of xylem production and(More)